WO2001094893A1

WO2001094893A1 - Fluid flow meter system

Info

Publication number: WO2001094893A1
Application number: PCT/CA2001/000801
Authority: WO
Inventors: Howard R. Harrison; Jeffrey R. Brown
Original assignee: Hb Innovation Ltd.
Priority date: 2000-06-05
Filing date: 2001-06-05
Publication date: 2001-12-13
Also published as: AU2001263691A1

Abstract

An electronic flow meter has conductive fluid flow sensors located inside a conduit, said sensors in communication with said power source, and said sensors adapted to allow an electrical current from said power source to flow between said sensors when a fluid is between said sensors. A signal processor increments a flow value temporally corresponding to a communication of the electrical current flow between the sensors and an installed time value corresponding to the elapsed time since the installation of a capacity rated element, and an indicator is activated when the flow volume or installed time exceeds set values. Also taught is an assembly to automatically shut off fluid flow when the set value is reached. Also taught is a replaceable integrated capacity rated element assembly containing sensors, power source and connections.

Description

Fluid Flow Meter System

Field of the Invention

This invention relates to an electronic flow meter for measuring the flow of any liquid that can act as a conductor of electricity, such as the flow of water through a water filter, and alerting the user regarding the status of a capacity rated element, such as a water filter

Acknowledgement of Prior Art

Recent certification requirements from the National Sanitation Foundation (NSF) have made it very desirable for water filter manufacturers to install a flow meter with their water filters. The ability to alert users when filter capacity has been reached means that manufacturers can publish a filter capacity that is within 20% of the theoretical capacity. The absence of a monitor / alert mechanism means that a 50% margin must be maintained.

There has been a tremendous amount of inventive activity in this field in response to NSF certification requirements and increased consumer demand. This is clearly indicated by the numerous flow meter designs that have been disclosed over the last several years including US patent 6,024,867 issued 2/15, 2000 to Parise (assigned to Water Safety Corp.), US patent 5,976,362 issued 11/2, 1999 to Wadsworth et al (assigned to The Clorox Company (Brita)), US patent 5,928,504 issued 7/27, 1999 to Hembre et al (assigned to Recovery Engineering (P&G)), US patent 5,888,381 issued 3/30, 1999 to Primdahl et al (assigned to United States Filter Corporation), US patent 5,858,215 issued 1/12, 1999 to Burchard et al (assigned to Moen Incorporated), US patent 5,458,766 issued 9/8, 1993 to Ehara, et al (assigned to Yuasa Corporation), US patent 5,328,597 issued 7/12, 1994 to Boldt Jr. et al (assigned to The Clorox Company (Brita)), US patent 5,236,578 issued 7/7, 1992 to Oleskow, et al (assigned to American Home Water Products), US patent 5,125,276 issued 9/12, 1990 to Wada (assigned to Kabushiki Kaisha Toshiba), US patent 5,121 ,639 issued 3/5, 1990 to McShane et al (assigned to Westinghouse Electric Corp), US patent 5,089,144 issued 2/18, 1992 to Ozkahyaoglu et al (assigned to Nartron Corporation), US patent 4,623,451 issued 11/18, 1986 to Oliver, US patent 4,484,582 issued 11/27, 1984 to Rottenberg, et al (assigned to Memorial Hospital for Cancer), US patent 4,436,223 issued 3/13, 1984 to Wilson, US patent 4,431 ,533 issued 9/15, 1981 to Rottenberg, et al (assigned to Standard Messgeratefabrik GmbH), US patent 4,363,244 issued 11/ 7, 1980 to Riadh et al, and US patent 3,885,244 issued 9/ 17, 1973 to Keller et al (assigned to Dr. Ing. Rudolf, Germany).

Three of the four most recent patents, US patent no. 5,888,381 assigned to United States Filter Corporation, US patent no. 5,928,504 assigned to Recovery Engineering (PUR, Proctor & Gamble), and US patent no. 5,976,362 assigned to The Clorox Company (Brita), represent the vast majority of installed units on the market today. The common element in all of these patents, and therefore the problem shared by all of them, is that they use mechanical sensors to measure the flow of water through the filter. US patent no. 5,888,381 uses water pressure to move a membrane which in turn moves a microswitch to activate an accumulating timer. US patent no. 5,928,504 and US patent no. 5,976,362 both use a water wheel mechanism to sense the water flow. All of these devices require moving parts that are difficult and costly to manufacture, and are subject to wear and possible failure. From a functional standpoint, they all provide a means to alert the user regarding the status of the filter, and one US patent no. 5,928,504 provides a means to shut down the filter when its capacity has been reached.

Other patents, including US patent 4,623,451 to Oliver, US patent no. 5,236,578 to Oleskow et al, US patent 5,858,215 to Burchard, and US patent 6,024,867 to Parise, also teach a flow meter in which an electrical current is activated by a mechanical or other means, in combination with a time accumulator and an indicator which is activated when the time accumulator reaches a preset point.

In contrast to the above, US Patent no. 5,458,766 issued to Ehara et al teaches a non- mechanical approach where a circuit is closed by the presence of flowing water via the electrical current which flows through the water. When the circuit is thus closed, a light emitting diode emits light. A battery is thus consumed while the light emitting diode is emitting light. The life of the filter cartridge corresponds to the life of the battery. The service life of the filter is considered to be exhausted when the battery has been consumed. The absence of an indicator showing activity of the battery while the water is flowing is apparently noticed by the user, indicating that the filter cartridge must be changed. Other patents, including US patent no. 4,436,223 to Wilson, also teach that the presence of a fluid is determined by the fluid providing an electrical path across a gap between two sensing electrodes. However in this case the objective is to monitor the number of times a pre-determined measured unit of conductive fluid is poured from a container. This patent does not disclose a time accumulator to measure the time during which the electrical path is across the gap, and it does not disclose an indicator which is activated when the time accumulator reaches a certain point.

US patent no. 5,328,597 to Bolt, Jr. et al also teaches contacts which, when immersed in water, close a circuit. However Bolt, Jr. et al do not teach a circuit linked to a time accumulator, nor do they teach a time accumulator linked to an indicator which is activated when the time accumulator reaches a preset point. As with '223 above, Bolt Jr, et al teach a system which records the number of uses, as opposed to the total duration of use.

Summary Of The Invention

In contrast to the above, the current invention discloses a low cost, compact, and completely electronic means to monitor a fluid flow using no mechanical or other moving parts, and requiring no special channels or intrusions into the fluid flow.

This electronic flow monitor is linked to a flow time accumulator which is then further linked to a user indicator that is activated when the time accumulator is substantially below, almost at, reaches or exceeds a preset point corresponding to the capacity of the capacity rated element. A second installed time accumulator monitors total installed time and is linked to the same user indicator which is activated when the total installed time reaches a preset point that may relate to the useful life span of the capacity rated element, regardless of the status of the flow time accumulator. The user indicator is only activated, based on the above algorithm, while the capacity rated element is in use and for a short time thereafter, thereby saving power.

The current invention also discloses a means to automatically sense capacity rated elements of different capacities, set the flow and installed time preset values accordingly, and then automatically reset both time accumulators when the capacity rated element is removed. The electronic flow meter may shut down the operation of the capacity rated element, when either the flow time accumulator or the installed time accumulator has reached a certain present limit, and do so in a manner that precludes the future use of the same capacity rated element.

Further, the current invention discloses a means to provide power for the electronic flow meter and user indicator from a battery that is imbedded in the capacity rated element and replaced as each new capacity rated element is installed.

Finally, the current invention discloses a means to provide logic level outputs so that the electronic flow meter may be installed in and easily integrated with the control system of appliances that may require a flow meter.

Accordingly this invention relates to an electronic flow meter which can be used, in an embodiment, to monitor the flow of water through a water filter and alert the user regarding the status of the filter relative to its rated capacity. The invention comprises (a) a circuit in a fluid conduit, which circuit is completed by the presence of a fluid, via a small current flowing through the fluid; (b) a flow time accumulator which accumulates time when the circuit is completed; (c) a second installed time accumulator which accumulates time since the first occurrence of the fluid flow; (d) an indicator which is activated when the time accumulators reach certain preset points (e) a means to automatically shut off fluid flow when a preset point has been reached; (f) a means to determine these preset points based on a feature of the capacity rated element, and to reset the timers when a new capacity rated element is installed; and (g) a means to temporarily de-activate the indicator when the fluid filter is not in use in order to save power.

This invention teaches an electronic flow meter consisting of a) a fluid conduit having a capacity rated element end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on the electrically insulated inner side, these sensors being in communication with the power source and adapted to allow an electrical current from the power source to flow between the sensors when a fluid is between the sensors; d) a signal processor in communication with the sensors and adapted to increment a flow value temporally corresponding to a communication of an electrical current flow between the sensors; and e) an indicator in communication with the power source and the signal processor; wherein the signal processor is configured to activate the indicator according to the status of the flow value relative to a set value.

The electronic flow meter may further include a pressure sensor located in the conduit and in communication with the signal processor. The pressure sensor is adapted to determine a quantity of pressure and to communicate a flow rate signal corresponding to this quantity of pressure to the signal processor. The signal processor is adapted to combine the flow rate signal with the signal produced by the electric current flow between the sensors to determine the adjusted flow value.

The electronic flow meter may further include a valve in communication with the power source and the signal processor, wherein the signal processor is configured to signal the valve to close when the flow value exceeds a set value.

The electronic flow meter may further include a real time accumulator adapted to accumulate time since a first installation of a capacity rated element. This real time accumulator is in communication with the signal processor, and the signal processor is adapted to activate the indicator when the accumulated real time exceeds a set value.

The electronic flow meter may further include a reset sensor in communication with the signal processor, and positioned such that inserting a capacity rated element into the conduit actuates the reset sensor. The reset sensor is adapted to reset the real time accumulator when the reset sensor is actuated. Also, the reset sensor is adapted to reset the flow value when the reset sensor is actuated.

The electronic flow meter may further include a signal amplifier communicating between at least one of the sensors and the signal processor. At least one of the fluid flow sensors may be located proximal to the output aperture end. The electronic flow meter may further include a constricted portion of the conduit located between the capacity rated element end and the fluid flow sensors, and wherein the pressure sensor, if used, is located in the conduit between the constricted portion and the capacity rated element end.

The signal processor within the electronic flow meter is adapted to detect the presence of different capacity rated elements and to detect various characteristics of the capacity rated element by detecting at least one of physical, magnetic, or other properties (such as capacitance or resistance) of the capacity rated element. The signal processor is configured to activate the indicator at two or more set values, and the indicator is configured to indicate two or more indications corresponding to the two or more set values. The signal processor is configured to activate the indicator for a set period of time after flow between the sensors has stopped. The signal processor may be further configured to detect a low power status of the power source and to signal the indicator, and the indicator is configured to indicate low power.

This invention also teaches an electronic flow meter consisting of a) a fluid conduit having a capacity rated element end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on the electrically insulated inner side, in communication with the power source, and adapted to allow an electrical current from the power source to flow between the sensors when a fluid is between the sensors; d) a signal processor in communication with the sensors and adapted to increment a flow value in response to a communication of the electrical current flow between the sensors; and e) a valve in communication with the power source and in communication with the signal processor; wherein the signal processor is configured to signal the valve to close when the flow value exceeds a set value.

This invention also teaches an electronic flow meter further including a flag actuated on the first use of the capacity rated element to prevent reuse of the capacity rated element.

This invention also teaches a capacity rated element assembly for use with an electronic flow meter apparatus and consisting of a) a power source located in the capacity rated element; and b) connections in communication with the power source and configured to communicate with the electronic flow meter apparatus to supply power to the apparatus. The capacity rated element assembly may further include an actuator adapted to reset the flow value when the capacity rated element is installed to the electronic flow meter apparatus.

The capacity rated element assembly may be further adapted to communicate various characteristics of the capacity rated element assembly to the electronic flow meter apparatus through at least one of physical, magnetic or other (such as capacitance or resistance) properties of the capacity rated element assembly.

The capacity rated element assembly may further contain a valve in communication with the power source and in communication the signal processor, wherein the signal processor is configured to signal the valve to substantially close when the flow value exceeds a set value, and the valve, once closed, provides a visible signal indicating its closure.

This invention also teaches an electronic flow meter wherein the signal processor is configured such that, upon activating the reset sensor, the signal processor sends the indicator a flush signal, and the indicator is configured to display a flush indicator. The signal processor is configured such that the flush indicator is displayed for an amount of time " corresponding to a set amount of flow.

The electronic flow meter may further include a real time accumulator adapted to accumulate time since an occurrence of the fluid flow. The real time accumulator is in communication with the signal processor, and the signal processor is adapted to activate a flush signal on the indicator when the time since an occurrence of the fluid flow exceeds a set value.

This invention also teaches an integrated capacity rated element assembly consisting of a housing containing: a) a fluid conduit having a connection end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on the electrically insulated inner side, in communication with the power source, and adapted to allow an electrical current from the power source to flow between the sensors when a fluid is between the sensors; d) a capacity rated element located in the conduit between the connection end and the fluid flow sensors; and e) a signal processor connection located proximal to the connection end and in communication with the power source and with the fluid flow sensors.

The integrated capacity rated element assembly may further include a dry conduit for communication from the power source and the fluid flow sensors to the signal processor connection, and a fastener proximal to the connection end and adapted for releasably securing the integrated capacity rated element assembly to a connection.

The integrated capacity rated element assembly may further include a lever and a valve actuated by the lever. The valve has a first position for directing the flow of fluid through the capacity rated element and a second position for directing the flow of fluid away from the capacity rated element. Alternatively the lever rotates the integrated capacity rated element assembly to actuate a valve proximal to the connection end and having a first position for directing the flow of fluid through the capacity rated element and a second position for directing the flow of fluid away from the capacity rated element. In the latter instance the fastener is adapted for releasably securing the integrated capacity rated element assembly to the valve while allowing the assembly to rotate to actuate the valve.

The integrated capacity rated element assembly may further include an air vent in flow communication with the fluid flow sensors and wherein a rotation of the integrated capacity rated element assembly opens and closes the air vent.

The integrated capacity rated element assembly may further include a fluid conduit that has a constricted portion.

The integrated capacity rated element assembly may further include a dry conduit that contains multiple subsets of connectors, each of the subsets corresponding to multiple integrated capacity rated elements of different capacities. The integrated capacity rated element assembly is configured to connect a unique subset of connectors to a corresponding set of signal processor connectors. The integrated capacity rated element assembly may be configured such that at least one of the connectors extends into the fluid conduit to form one of the sensors.

The integrated capacity rated element assembly may be configured such that the power source is intentionally drained by the signal processor when a set value for the capacity rated element has been exceeded.

In an alternative embodiment the conductive fluid flow sensors are located external to the integrated capacity rated element assembly, and the connections to the signal processor and the power source are re-configured accordingly.

In an alternative embodiment the signal processor within the electronic flow meter is adapted to communicate with the control processor(s) of an appliance in which the electronic flow meter is installed.

The capacity rated element within the electronic flow meter, the capacity rated element assembly, or the integrated capacity rated element assembly may be a filter or any other type of capacity rated element such as a purifier, a controlled volume fluid dispenser or mixer, a disposable component or fluid which has a useful life dependent upon total flow, or a fluid moving device, such as a pump, which must be serviced after a certain throughput.

The power source within the capacity rated element assembly or the integrated capacity rated element assembly may be electrical or mechanical. Further, the power source used by an integrated capacity rated element assembly may be external to the integrated capacity rated element assembly.

This invention teaches a method for indicating the status of a capacity rated element, including the steps of: (a) registering the installation of a capacity rated element; (b) resetting an accumulator upon the registering of installation of a capacity rated element; (c) detecting a flow of fluid in association with the capacity rated element; (d) incrementing a time value of the accumulator while detecting a flow of fluid; (e) determining whether the used time value is greater than a set value; and (f) actuating an indicator when the used time value is greater than a set value.

This invention also teaches a method including, after step (d), incrementing a real time value of a real time accumulator; determining whether the real time value is greater than a real time set value; and actuating an indicator when the real time value is greater than a real time set value.

This invention also teaches a method including several set values and at least one indicator.

This invention also teaches a method including, after step (e), closing a valve when one of the time values is greater than a corresponding set value.

This invention also teaches a method including, after step (a), determining whether the power level of a power source is below a set power value; and actuating an indicator when the power level is below the set power value.

This invention also teaches a method including, after a cessation of flow, accumulating a flush time value; and determining whether the flush time value is greater than a set flush value; and actuating an indicator when the flush time value is greater than a set flush value.

This invention also teaches a method including, during step (c), sensing a pressure of the fluid; and during step (d) modulating the incrementing by a factor related to the pressure to correspond the incrementing to an actual flow rate.

This invention also teaches a method including, after step (a), resetting the set values to correspond to a specific capacity rated element.

Finally, this invention teaches a pitcher apparatus which combines a pitcher and an electronic flow meter. The pitcher apparatus includes high level detectors for detecting a high level of fluid in the pitcher, low level detectors for detecting a low level of fluid in the pitcher, and fluid flow sensors at the pitcher outlet for detecting a fluid flow. The level detectors are in communication with the signal processor, and the signal processor is adapted to combine the communications from the level detectors with the electric current flow between the fluid flow sensors to determine the flow value.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described by way of example with reference to the drawings in which:

Figure 1 is a functional diagram of the electronic flow meter showing the fundamental components, Figure 2 is a pictorial view of a vertically oriented faucet mount water filter with a cutaway showing the electronic flow meter components in context,

Figure 3 is a pictorial view of a horizontally oriented faucet mount water filter with a cutaway showing the electronic flow meter components in context, Figure 4 is a detailed view of the electronic flow meter sensors showing a pressure sensor, Figure 5 is a block diagram of the electronic flow meter control circuit, Figure 6 is a schematic diagram of the electronic flow meter control circuit, Figure 7 is a flow chart for the electronic flow meter control software, Figure 8 is a cross sectional view of an imbedded power faucet mount water filter with a replaceable filter element. Figure 9 is a cross sectional view of an imbedded power faucet mount water filter with an integrated filter element / housing assembly,

Figure 10 is a detailed view of the integrated filter element / imbedded power interconnect with automatic sensors for different filter sizes, Figure 11 is a side view of a faucet mount water filter with an automatic dispenser mechanism, Figure 12 is a pictorial view of an electronic flow meter in a refrigerator application with water dispense interconnect, Figure 13 is a pictorial view of the electronic flow meter in an under sink application with audible user indicator, Figure 14 is a pictorial view of an electronic flow meter in a filter water dispenser with head sensitive flow adjusters.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The electronic flow meter can be used to measure the flow of any liquid that can act as a conductor of electricity. Two conductive fluid flow sensors are located in an electrically insulated inside surface of a fluid conduit. These sensors sense the flow of fluid through the conduit by passing a very low current through the fluid when the fluid is present. The sensors are located proximal to an opening in the conduit such that the fluid only contacts the sensors when the fluid is flowing through the conduit. The absence of fluid removes this conductor, and the flow of electricity between the sensors is interrupted.

The electronic flow meter is generally for use in association with capacity rated elements such as a fluid filter. The sensors are connected to an accumulating timer that will only increment when water is flowing. This information can be used to calculate the total amount of fluid that has passed through the filter because of the simple relationship between time, flow rate, and total flow - i.e. (Total flow through filter) = (Flow rate) x (Total flow time).

The output of the flow time accumulator can be constantly compared with certain preset values that relate to the fluid filter. A user indicator is then activated according to the results of this operation, thereby keeping the user informed regarding the status of the fluid filter relative to the preset values. The user indicator may be a single LED indicator that changes color and / or mode when the filter is well under capacity (say less than 90% utilization), close to capacity (90% to 100% utilization) and at capacity (100% utilization).

The logic signal associated with the "at capacity" state may also be used as a signal to shut down the filter by closing a valve in the filter element or in the filter housing, and/or locking out the filter control mechanism. In a faucet mount water filter, this control mechanism is generally a "toggle" switch or rotating fluid filter element housing which the user moves to select either (1 ) normal mode where the water flows from the tap or (2) filter mode where the water is diverted through the fluid filter.

The energy required to close a valve in the filter element may be stored in a spring that is integral to the filter element and comes preloaded with each new filter element. The energy stored in this spring may also be used to move a physical barrier into place that would prevent the re-installation of the same expired filter element once it has been removed, although closing an internal valve which prevents the flow of water through the filter element may be sufficient to prevent it's re-use. The release of this energy may be triggered by a small solenoid that is actuated by the "at capacity" logic signal from the electronic flow meter.

The energy required to close a valve located in the filter housing, or lock out the filter control mechanism, may be stored in a spring that becomes loaded as each new filter is installed, or it may be obtained from the battery that generally powers the electronic flow meter. The former method only relies on the internal battery to trigger the shut down operation rather than using it to complete the task, thereby saving power and increasing battery life. In the latter case a bi-stable (latching) solenoid valve / actuator may be used to limit power requirements.

It should be noted that the accuracy of the total flow calculation as outlined above is based on an assumed constant flow rate. This is a reasonable assumption in the case of a faucet mount water filter since (1) the geometry of the filter housing is designed to provide a constant flow rate through the filter itself by directing the filtered water under relatively constant pressure through a fixed exit orifice and (2) the current NSF certification requirements allow a reasonably wide flow measurement tolerance of - 20% to + 10%. If this assumption does not provide the required accuracy in certain applications, then an electronic pressure sensor is placed inside the filter housing such that the pressure drop across the fixed exit orifice, as the fluid flows out to a zero pressure area, may be determined. This information can then be combined with the output from the flow sensors to more accurately calculate water flow.

A second installed time accumulator tracks the total fluid filter installed time, independent of fluid flow through the filter. This is required since some fluid filters may have a predetermined shelf life once installed and activated, much like a "best before date" for opened food items. The installed time accumulator may also be used to track the time between uses of the fluid filter since it may become inactive prior to the end of shelf life due to very infrequent use. The output of the installed time accumulator may be used to activate the same user indicator that is linked to the flow time accumulator, or it may be linked to an independent user indicator. The output signal may also be used to prevent further use of the filter as described above.

Both timers should be reset when the filter is replaced. This can be accomplished by sensing the presence or absence of a feature integral to the filter element, or by sensing the removal / replacement of the cap that must be removed to replace the filter. The feature integral to the filter element may be a permanent magnet that is imbedded in the filter body at a location dependent upon filter capacity, a protrusion or other feature dependent upon filter capacity, or some other type of physical or electronic identifier.

When an imbedded magnetic sensor is used, removing the filter will also remove the magnet. A sensor built into the filter housing senses this change and resets the timers accordingly. The installation of a new filter again places a new permanent magnet close to the appropriate sensor for the filter's rated capacity. This information is used to start the installed time accumulator, enable the flow time accumulator, and set the preset values accordingly. The second timer will not begin to increment until fluid starts to flow through the filter.

Operation is similar with a mechanical sensor, except that a protrusion or other feature on the filter may be used to activate a microswitch that is connected to the electronic flow meter controller. Further, some characteristic of the protrusion, e.g. location, may be dependent upon the rated filter capacity. In this case multiple microswitches, or multiple position microswitches, may be used to detect the presence of filters with varying capacities.

In many cases access to the filter (for replacement) is accomplished by removing a cover or "cap". In these cases the timer reset function can be accomplished by having a sensor that is only activated when the cap is "closed". This approach may be best suited to those cases where filters of only one capacity will be used.

It is possible that the user may accidentally re-install an old filter, unless a valve internal to the filter element had been activated to prevent the further flow of water through the filter element as described above, and this would go undetected by the reset mechanisms which would inadvertently reset the timers and prepare the flow meter for another cycle. This can be prevented by blocking the second installation of the filter element with a mechanical feature, such as a protrusion, that is only activated upon the first installation of said filter. Alternatively, the provision of a unique electronic signature for each individual filter element would allow the electronic flow meter to determine if a pre-used fllter element had accidentally been re-installed since the signature could be compared with those of previously installed filter elements upon each new installation.

The present inventors have also developed a means to automatically dispense the water through the filter. Current products on the market require two steps - one to turn on the main supply tap, and another to divert the flow of water through the filter. The automatic dispense mechanism will reduce this to one step by using a mechanical actuator under the filter to detect and respond to the presence of a glass, thereby diverting the flow of water through the filter as soon as the main supply tap has been turned on. A manual bypass will allow the filter to be turned to "constant on" when filling pots or other large containers. Further, a venting mechanism may be integrated with the automatic dispense mechanism so that the water flow sensors will be automatically "cleared" when water is no longer flowing through the filter, thereby preventing any extraneous signals from the water flow sensors. The new water filter system, including the automatic dispense mechanism, may be configured such that a removable "one piece" filter element and housing assembly may be attached to the main body of the water filter system with a single water connection.

The description of the invention, to this point, has focused on applications where power for the electronic flow meter comes from a battery located in the filter housing. The present invention also teaches that this power may be conveniently provided by a battery imbedded in the filter element. As a result of this development, henceforth referred to as imbedded power, a new battery is installed with each new filter element. This substantially reduces the probability of the battery becoming exhausted part way through the life of a filter element, a situation that is currently dealt with by relying on the user to (1 ) notice that the indicator light does not function as it should and then (2) replace both battery and filter to "be on the safe side". It also means that the user will never need to (consciously) change a battery. Since imbedded power provides a new battery with each new filter, there will be more power available for the electronic flow meter as well as other components within the filter housing.

Imbedded power water filters may be used in several different configurations including a traditional canister style filter housing with a removable element or a completely removable "one piece" filter element and housing assembly. In the former case, electrical contacts may be placed in the filter housing that will line up with the battery contacts on the imbedded power filter element assembly once the cap is placed on the canister. In the latter case the battery contacts may be integral to the water supply tube that connects the one-piece element / housing assembly to the plumbing adapter. In both cases the battery and the contacts need to be in "non wetted" areas to prevent corrosion of the contacts, and more importantly to prevent contamination of the filtered drinking water.

The availability of power in the filter housing simplifies all of the required operations to a substantial degree. First, the removal of power that is now coincident with the removal of the filter element can be used to reset the accumulating timers. The restoration of power that now accompanies the installation of a new filter can be used to enable the flow time accumulator and initiate the installed time accumulator. Multiple power contacts corresponding to multiple filter element capacities may be used to determine the rated capacity of the new filter element, and to set the preset values accordingly. This precludes the requirement for an imbedded permanent magnet and a corresponding sensor, or some type of capacity sensitive mechanical device as described above.

Second, the imbedded power battery may provide more power than is required for the electronic flow meter, and this may be used to accomplish flow control. Mechanical toggle switches can be replaced by simple electric push buttons that will activate the required toggle valves. A momentary push button or a lever activated momentary contact may be used to sense the presence of a glass and therefore direct the flow of water through the filter element. A dual position slide switch could be used to implement the "constant on" mode required to fill pots and other large containers. It should be noted that electronic flow control is actually a safety feature since the user cannot mistakenly run water through the filter housing when no filter element is installed. This is because the power required to activate the control valves is removed with the filter. No filter results in no power, and the valves will not operate.

Third, the end of filter life shut down may be accomplished quite easily since the control circuit can simply disable the flow control switches. As a further measure, the remaining power in the imbedded power battery can be intentionally drained to ensure that the filter can't be re-activated even if the same filter element were to be accidentally re-installed as a new one. This precludes the requirement for mechanical features or electronic signatures as outlined above to prevent the accidental re-use of a filter element.

One of the commonalities between both types of filters - traditional or imbedded power - is the requirement for a user interface to provide information about the status of the filter element. The electronic flow meter provides tremendous flexibility to provide for a variety of user interfaces since the unit is based on software driven microprocessor technology. The user interface could be as simple as one or two LEDs (e.g. faucet mount filter) or an audible signal (e.g. under counter filter), or as complex as an LCD panel or even a communication channel to another appliance or PC.

In the simplest cases the user interface may be comprised of one green LED and one red LED, or perhaps one LED with a green and red filaments. The green LED or filament can be used to communicate that the unit is functioning properly - i.e. that the filter element is operating at substantially below its rated capacity and substantially within its shelf life limits. Both LEDs, or in the case of one LED, both filaments, may be used to communicate that the filter element is approaching its rated capacity or shelf life limit. Finally, the red LED or filament can be used to communicate that the filter element has reached its rated capacity or shelf life limit. The red LED or filament may be further programmed to display a distinct pattern when the rated capacity or shelf life has been exceeded by an unsafe margin, especially in configurations where a positive shut-off at end of filter life cannot be offered.

The electronic flow meter can be programmed to save power by using a low power display mode such as flashing when the filter is in use, and further by automatically shutting down the user interface when the user has left the area - perhaps determined by a preset number of minutes after the filter has been used. The user interface would then be re-activated as soon as the filter is used again. This ability to save power is extremely important for any battery operated device.

The electronic flow meter has logic level outputs which can communicate with other electronic devices, and therefore it is ideally suited for use in water use appliances such as coffee makers or refrigerators with icemakers and / or drinking water dispensers. The electronic flow meter can interoperate with the appliance's control system to alert the user, shut down the water use feature, etc. Since power is readily available in appliances, it is unlikely that imbedded power filters will be required for these applications.

FIG. 1 provides a functional overview of the electronic flow meter and shows two stainless steel or other electrically conductive and non-corrosive water flow sensors 10 imbedded in the electrically insulating material of filtered water outlet 12. The presence of filtered water flow 14 through filter water outlet 12 provides an electrical path between water flow sensors 10, allowing current to flow between the sensors in response to a small voltage applied across the sensors by control circuit 16. It follows that the absence of filtered water flow 14 will prevent the current from flowing. Control circuit 16 is designed to sense the presence or absence of this current, indicating the presence or absence of filtered water flow 14.

Control circuit 16 contains a timer 18 which increments as filtered water flow 14 is present. Timer 18 has the facility to store the accumulated value when filtered water flow 14 is absent. This stored accumulated value is then used as the starting point when timer 18 begins to increment in response to a second presence of filtered water flow 14. In this manner the accumulated output of timer 18 will reflect the total accumulated time during which flltered water flow 14 has been present.

The accumulated output of timer 18 may be used to calculate the total filtered water flow 14 since it can be assumed the water is flowing at a constant rate as determined by the average filtered water flow 14 flow rate over the life of filter element 24. This assumption is reasonably accurate since the rate of filtered water flow 14 is controlled by a fixed orifice 20 which has a reasonably constant input pressure and a constant zero output pressure as it releases filtered water flow 14 into the open air. The pressure on the input side of fixed orifice 20 is reasonably constant as determined by the pressure behind tap water input flow 22.

The relationship between the accumulated output of time 18 and the total filtered water flow 14 can therefore be determined by using the following formula;

Accumulated output X Assumed constant Total flltered of timer 18 flow rate water flow 14 This same formula can be used to determine the maximum accumulated output of timer 18 that will be associated with a certain maximum total flltered water flow 14. This maximum total filtered water flow 14 will be equal to the rated capacity of filter element 24.

Rated capacity of filter element 24

Maximum accumulated output of timer 18

Assumed constant flow rate

This vastly simplifies the logic required in control circuit 16 since time values can be used directly rather than calculated flows. The accumulated output of timer 18 can be constantly compared to the maximum output of timer 18, as defined above, to determine the status of filter element 24 relative to its rated capacity.

The status of filter element 24 may be communicated to the user through indicator light 26. The user may be advised of normal operating conditions while filter element 24 remains well under rated capacity. Then the user may receive various degrees of warning as the filter approaches, reaches, and then exceeds rated capacity. Indicator light 26 may be configured to provide a variety of colors or modes of warning, such as steady, single pulse or flashing, through one or more LEDs. Alternatively the indicator may incorporate an audible signal to compliment the LEDs or provide a useful warning in applications where an LED would not be visible.

The further use of filter element 24, after it reaches or exceeds rated capacity, may be prevented by substantially stopping the further flow of water through filter element 24. At the appropriate time control circuit 16 energizes solenoid actuator 21 which then sends plunger 23 briefly through a small access hole in the wall of filter element 24. (The small access hole prevents the user from accidentally activating the shut down mechanism.) This in turn moves valve barrier 25 sideways to the extent that barrier hole or penetrable membrane 27 is positioned directly above shut-off valve plunger 29, releasing the energy in valve spring 31 as it pushes shut-off valve plunger 29 up through barrier hole or penetrable membrane 27 as well as through seal and penetrable membrane 33. Once this occurs, shut-off plunger 29 blocks the water entry point to filter element 24 and stops substantially all of tap water input flow 22. The visible side of shut-off plunger 29, as seen by the user through the water entry point to filter element 24 after it has been removed, may be colored red to provide a visible and enduring indicator that the filter has been used and has expired.

It should be noted that this mechanism utilizes the potential energy stored in valve spring 31 to close the valve rather than energy from the battery that powers the electronic flow meter. Only a minimal amount of battery power is used as a trigger to release the energy stored in valve spring 31 , thus minimizing any negative impact on battery life.

Seal and penetrable membrane 33, and possibly barrier hole or penetrable membrane 27, once pierced, will seal around shut-off valve plunger 29 to prevent the back flow of water out through the hole in filter element 24 which allows plunger 23 to access valve barrier 25. Alternatively, plunger 23 could access valve barrier 25 through a flexible membrane. However it is still important that seal and penetrable membrane 33 block the flow of water into valve cavity 35 during normal operation as this could adversely affect the water and the performance of filter element 24.

It is important to note that shut-off valve plunger 29 could be located at either the entrance to or the exit from filter element 24, and that it does not need to entirely block the flow of water through filter element 24 - in other words it does not need to be a perfect valve. The intent is to block substantially all of the flow so that the further use of filter element 24 is no longer practical. It is equally important to note that this is an irreversible process, and that filter element 24, once expired in this manner, may not be accidentally re-used.

Reset activator 30 is an integral part of filter element 24, and is removed and replaced with filter element 24. Reset activator 24 may be a physical feature, such as a protrusion, a magnetic feature, or some other detectable characteristic of filter element 24. Reset sensor 28 is accordingly designed to sense the presence or absence of this detectable characteristic.

Reset activator 30 and reset sensor 28 may be further designed to communicate various filter characteristics such as capacity and average flow rate in applications where different types of filters may be used in the same device. As an example, filter element 24 may contain one of two possible reset activators 30 in locations A or B to indicate a corresponding filter element 24 capacity A or B. One of the reset sensors 28 located at A and B will sense the reset activator 30 and communicates this information to control circuit 16. A reset activator 30 at location A indicates that filter element 24 has capacity and average flow rate A, and one at location B indicates that filter element 24 has capacity and average flow rate B. Other filter characteristics may also be reset in a similar manner.

Control circuit 16 will sense that an old filter element 24 has been removed since reset activator 30 will also be removed. Control circuit 16 will likewise sense the new filter element 24 since a new reset activator 30 will also be installed. This information is used to automatically reset the accumulated output of timer 18 each time the filter is replaced. Further, the maximum accumulated value of timer 18 may be reset according to the capacity of the new filter element 24 if it is different than the capacity of the old filter element 24.

Care must be taken to locate water flow sensors 10 in an area that automatically drains once filtered water flow 14 stops. Water flow sensors 10 may provide a false signal if water is allowed to remain in the area of the sensors after water flow 14 stops since the remaining water will provide some level of conductivity. The sensors are most ideally located in a vertical section of the piping with an open end at the bottom. This is most typically in the inner side of filter water outlet 12.

FIG. 2 is a pictorial view of a vertically oriented faucet mount water filter with a cutaway showing the electronic flow meter components in context. Tap water normally flows from faucet 40 through to tap water outlet 42 unless water flow control switch 44 is in the vertical orientation. Once water flow control switch is placed in the vertical orientation water is diverted through filter element 24. The water exits filter element 24 under relatively constant pressure through fixed orifice 20, and then flows through filter water outlet 12.

Water flow sensors 10 are located in the non electrically conductive sides of filter water outlet 12. Water flow sensor lead wires 31 connect water flow sensors 10 to control circuit 16 which may be conveniently located within faucet mount housing 32. Indicator light 26 may be conveniently mounted in the side of faucet mount housing 32 such that it is visible to the user. Battery 48 is located adjacent to control circuit 16. Filter element 24 may be replaced by first removing filter cap 46 which is threaded onto faucet mount housing 32. Reset activator 30 is imbedded in filter element 24 such that it aligns with reset sensor 28 when a new filter element 24 is installed. Reset sensor 28 is retained in faucet mount housing 32, rather than filter cap 46, so that no electrical connections are required between control circuit 16 and filter cap 46. Reset sensor 28 is connected to control circuit 16 through fixed lead wires.

Control circuit 16 is modular and may be physically detached from water flow sensors 10 and reset sensor 28 and yet connected electrically through lead wires. This means that control circuit 16 may be placed conveniently anywhere in faucet mount housing 32. In particular, it means that control circuit 16 does not need to be located under filter element 24, as in some current designs. The overall effect is that the overall height of the unit can be reduced, contributing to a much less bulky appearance.

FIG. 3 is a pictorial view of a horizontally oriented faucet mount water fllter that has all of the electronic flow meter components mounted in removable cap 50. The connection to faucet 40 and the operation of water flow control switch 44 remain the same as for the vertically oriented unit described in FIG. 2.

The horizontally oriented unit is longer as measured from back to front. However the unit is much shorter, top to bottom, since filter element 24 is mounted horizontally, and therefore it appears to be less bulky than the vertical design depicted in FIG. 2. In certain horizontal designs where filter cap 46 is affixed to faucet mount housing 32, filter element 24 may be replaced by removing component cap 50. Alternatively, in other horizontal designs where component cap 50 is affixed to faucet mount housing 32, filter element 24 may be replaced by first removing filter cap 46.

Component cap 50 contains all of the electrical components associated with the electronic flow meter including water flow sensors 10, control circuit 16, indicator light 26, reset sensor 28, battery 48, and all of the connecting lead wires. Component cap 50 also contains filtered water outlet 12 which directs the filtered water downwards after it flows through filter element 24 and fixed orifice 20. Filtered water outlet 20 is also conveniently self draining, thereby preventing any extraneous signals on water flow sensors 10. Reset activator 30 is an integral part of filter element 24, and is positioned such that it activates reset sensor 28 when a new filter element 24 has been installed. Multiple reset activators 30 may be used to communicate various filter element 24 characteristics as described above.

FIG. 4 is a detailed view of the electronic flow meter sensors showing a pressure sensor. This may be useful in certain circumstances where the water pressure cannot be assumed to be constant.

Filter element 24 is generally contained within filter element housing 60. Filter element canister 60 extends into filtered water outlet 12, and o-ring 62 seals the joint against leaks.

Filtered water flows out of filter element 24 under pressure and encounters fixed orifice 20.

After flowing through fixed orifice 20 it is released downwards into zero pressure as filtered water flow 14. Filtered water flow 14 will remain constant for as long as water flows through filter element 24 under constant pressure. More specifically, the water pressure just above

(or before) fixed orifice 20 must remain constant for this constant flow assumption to be true.

In some cases the water pressure will fluctuate, and this is acceptable so long as the corresponding variations on flow rate can be tolerated. As an example, current NSF certification requirements allow for a - 20% to +10% fluctuation in flow measurement. This certainly allows for underlying water pressure fluctuations.

In other cases the flow measurements must be more accurate, and variations in flow rate must be accounted for. It is known that the rate of filtered water flow 14 is determined by the size of fixed orifice 20 and the pressure of the water as it enters fixed orifice 20 (given that the water always exits into a zero pressure area beyond fixed orifice 20). Since the only variable is the pressure of the water as it enters fixed orifice 20, this information can be used to determine the rate of filtered water flow 14.

Pressure sensor 64 is mounted just above fixed orifice 20 to monitor the pressure of the water as it enters fixed orifice 20. Control circuit 16 (reference FIG. 1) uses this information to determine the rate of filtered water flow 14, which can then be integrated over time, as determined by signals from water flow sensors 10, to calculate total filtered water flow 14. This combination of sensors could be used in many applications that require a more accurate flow measurement.

FIG. 5 presents a block diagram of the electronic flow meter including the water flow sensors 10, amplifier 72, signal processor 74, and user indicator 26. The voltage applied across water flow sensors 10 is intentionally low to keep the current between the sensors, and therefore through the water, at a very safe level. As a result the signal strength output from water flow sensors 10 is extremely low and often cannot be used directly by signal processor 74.

Amplifier 72 serves to boost the output from water flow sensors 10 to standard logic levels. This allows for the use of standard components for the remainder of the circuit. The amplifier also serves to filter out extraneous signals that might results from, in particular, damp conditions around water flow sensors 10.

Signal processor 74 may be comprised of discrete components or a standard microprocessor such as a Microchip 12C1508C. The use of a microprocessor provides additional flexibility since the functionality of the device may be changed through software without requiring changes in the hardware configuration.

Amplifier 72 and signal processor 74 are both integral to control circuit 16 to facilitate the interconnection between these two modules. Control circuit 16 also serves as a connection point for the output from all sensors. The signal processor 74 accepts all signals directly except for the output from water flow sensors 70 which is first amplified by amplifier 72 as described above.

The output from signal processor 74 is used to control user indicator 26. User indicator 26 may be comprised of one green LED and one red LED, or perhaps one LED with a green filament and a red filament. The green LED or filament may be used to communicate that the unit is functioning properly - i.e. that the filter element is operating at substantially below its rated capacity and substantially within its shelf life limits. Both LEDs, or in the case of one LED, both filaments, may be used to communicate that the filter element is approaching its rated capacity or shelf life limit. Finally, the red LED or filament can be used to communicate that the filter element has reached its rated capacity or shelf life limit. The red LED or filament may be further programmed to display a distinct pattern when the rated capacity or shelf life has been exceeded by a unsafe margin, especially in configurations where a positive shut-off at end of fllter life cannot be offered.

The output of signal processor 74 may be further connected to other electronic equipment, such as an appliance controller, through a logic level interface. This is particularly useful in applications where the EFM is installed in a water use appliance such as a refrigerator or a coffee maker. In these cases the end-of-life signal may be used to shut down functions related to the water filter, thereby prompting the user to replace the filter element and preventing potentially dangerous use of the filter element.

FIG. 6 is a schematic diagram of control circuit 16 including amplifier 72 and signal processor 74 (comprised of microprocessor 82 and associated components). In this simplified application, capacity sensors 76 and pressure sensor 64 are not implemented. Also, amplifier 72, signal processor 74, and user indicator 26 are mounted on the same printed circuit board. In such applications the printed circuit board may be hermetically sealed, either in a sealed case or surrounded with an epoxy or other suitable potting material, such that the lead wires extend through the sealed package and the user indicator 26 is visible' outside of the sealed package. Further the sealed package may be mounted such that the user indicator 26 is visible through a window or other suitable opening in the water filter's faucet mount housing 32 (reference FIG. 2).

The microprocessor 82 is initially turned on by reset sensor 28 which connects pin 1 of microprocessor 82 to +V DC, i.e. the positive terminal of battery 48. Pin 8 of microprocessor 82 is likewise connected to the negative terminal of battery 48 to complete the power circuit. Reset sensor 28 also serves to reset both time accumulators (flow time and installed time), internal to microprocessor 82 and controlled by software within microprocessor 82, by pulling pin 4 of microprocessor 82 to a logic high through resistor R7. Reset sensors 28 may be connected to R7 only, performing just the reset function and leaving power applied to microprocessor 82 at all times, in configurations requiring non-volatile memory to store information such as electronic signatures for filter elements between filter changes. Microprocessor 82 begins to increment the installed time accumulator as soon as a new filter element is installed and the timers are reset as described above. The flow time timer will only increment when water is flowing past the water flow sensors 10.

Water flow sensors 10 are electrically connected to amplifier 72 through resistors R1 and R2. Resistors R1 and R2 limit the flow of current between water flow sensors 10, and therefore the flow of current through the water since water flow sensors 10 are immersed, to safe levels. Further, R1 serves to limit the current through the water should the water ever become accidentally connected to electrical ground 80. This situation might occur if water ever penetrated the hermetic seal around control circuit 16 or the battery compartment. Alternate amplifier 72 circuits may intentionally connect one of the water flow sensors 10 to ground, and reconfigure the transistors and gating components accordingly, to remove this problem.

The flow of current between water flow sensors 10, i.e. the flow of current through the water flowing past water flow sensors 10, serves to elevate the base voltage of transistor T1 to the extent that transistor T1 is turned on. Transistor T1 then serves to turn on transistor T2 which then allows a current to flow through R4, dropping the voltage on pin 7 of microprocessor 82 to a logic low. Microprocessor 82 is thus informed that water is flowing past water flow sensors 10, and begins to increment the flow time timer. The flow time timer is an accumulating timer, meaning that it will always retain the last value and begin to increment from that point forward each time the filtered water flow is initiated.

Microprocessor 82 contains the required preset flow and installed times as determined by a particular application. The software is designed to pull pin 6 low when the flow time and installed time timers are substantially below their preset values, drawing current through and illuminating green LED filament 84 in user indicator 26. Then, the software will also draw pin 2 low to simultaneously draw current through and illuminate red LED filament 86 when the flow time or installed time timer is approaching its preset value. (The simultaneous illumination of both green LED filament 84 and red LED filament 86 produces an amber color output. Resistor R6 limits the total current through both filaments, reducing the intensity of each and increasing the amber effect when both are illuminated.) The software will pull pin 6 high to turn off green LED filament 84 while leaving red LED filament illuminated when either the flow time or installed time timers reaches its preset limit, indicating that the filter has reached end of life. Finally, the software changes the mode of red LED filament 86, for example from steady to flashing or visa versa, when either the flow time or installed time timer has exceed the preset value by an unacceptable margin. Alternatively, the system may be configured to proactively shut off the flow of water through the filter when either preset maximum has been reached, preventing any further use until such time as the filter is replaced.

The above sequence has been simplified so that the electronic functions may be more easily understood. In practice, microprocessor 82 will only turn on the green and / or red filaments 84 / 86, appropriate to the status of the filter, when water is flowing through the filter element and for a short time thereafter in order to save power. This provides a suitable user indicator 26 when the filter is in use, but does not waste power by illuminating the LED(s) when the user is not present. Further, the LED(s) may be pulsed or flashed rather than constantly illuminated in order to further conserve power.

Figure 7 presents a flow chart for the software that controls microprocessor 82. After initiating microprocessor 82, all functions and accumulators are reset including the Install Time Accumulator (ITA) and Flow Time Accumulator (FTA). Then, the software checks for the presence of a filter and sets the preset values for the timers accordingly. Then, the ITA begins to increment immediately on a time controlled basis.

A battery check feature may be inserted at the beginning of the program to warn the user to change a partially depleted battery that is likely to become exhausted before the newly installed filter reaches end-of-life. This could be a physical battery status check, detecting the voltage available at the battery terminals, or a status determined by relevant indicators such as the number of filters that have been previously serviced by the same battery (i.e. the number of resets since the last battery change), the total installed time for all filters since the last battery change, or some combination thereof. Should the battery not pass these threshold tests, the user may be alerted through the user indicator light. For example, a rapidly flashing red LED seen immediately after the installation of a new filter would indicate that the battery needs to be replaced. In a similar manner a flush monitor feature may also be inserted at the beginning of the program to warn the user not to drink from the first amount of water to run through the filter, (approximately one gallon - specific amount to be determined by the filter element manufacturer) as this may contain carbon particles and entrapped air. This warning could be accomplished simply by flashing the LED(s) in a unique manner, perhaps alternating yellow / green, to indicate that the water should not be consumed. It is also possible to track the time between uses of the filter element, by storing and comparing relative values taken from the ITA at each time of use, and to activate the flush monitor if the filter element needs to be flushed once again. In this case the flush monitor LED pattern may relate to the appropriate phase of the filter's life - i.e. flashing predominantly green / yellow during normal use, flashing predominantly yellow / red during the imminent expiration phase, and so on. Using this algorithm, the user would always be aware that the filter was being flushed as indicated by the alternate color flashing pattern of the LED(s), even though the colors may change during the life of the filter.

The software will increment the ITA on a time controlled basis during the battery check and flush monitor procedures, and will continue to do so until such time as the filter is removed. However the software will only begin to increment the FTA on a time controlled basis once water flow is detected, and continue to do so for only as long as filtered water continues to flow, providing that the ITA does not reach 100% or the FTA does not reach 105% in the interim. Should the timers reach these maximums based on a percentage of the preset values, then the Red LED will be turned on and left on until such time as the filter is removed.

Prior to reaching these maximums, the software will continue to set the LEDs according to the following algorithm (Table 1) until such time as the filtered water flow is stopped. At that time the software will set a delay timer to leave the LED(s) set according to the last available status for, say, a 2 minute period of time and also return to a "wait" status where it continues to increment the ITA on a time controlled basis and waits for the next time a filtered water flow is detected. Removing the filter at any time will cause microprocessor 82 to be reset. Table 1

Installed Time Flow Time LED Accumulator (ITA) Accumulator (FTA) Display % of Preset % of Preset

0 to 100% AND 0 to 90% Flashing Green

0 to 100% AND 90 to 100% Flashing Amber (Green + Red)

0 to 100% AND 100 to 105% Flashing Red

> 100% OR > 105% Solid Red

Although the preceding chart refers to percent of preset values for simplicity, each of the trigger points may actually be considered as an independent set value calculated as a percent of the corresponding preset value. For example the LED will display flashing green while the ITA is below its 100% set value and the FTA is below its 90% set value.

In applications where acceptable flow meter tolerances require the use of a pressure sensor (reference FIG. 4), the software may adjust the effective flow rate by adjusting the manner in which the FTA is incremented. Whereas the FTA is normally incremented on a consistent time controlled basis, a lower than normal pressure reading would cause a corresponding longer time between FTA increments. Conversely, a higher than normal pressure reading would cause a correspondingly shorter time between FTA increments. This approach keeps the flow volume / time increment constant by changing the length of the time increment in response to changes in flow rate. As a result, the same FTA preset values may be used irrespective of flow rate changes. Note that the ITA will always be incremented on a consistent time controlled basis, regardless of any flow rate changes.

Figure 8 is a cross sectional view of an Imbedded power faucet mount water filter with a replaceable filter element. In this case filter element canister 60 contains both filter element 24 and battery compartment 92. Battery compartment 92 serves to hold battery 48 and keep it isolated from filter element 24. Various configurations are possible, provided that battery 48 is separately contained within filter element canister 60.

Filter element 60 receives water through a sealed connection with tap water inlet 96, processes the water through filter element 24, and then allows the flltered water to exit through a sealed connection with filtered water outlet 12 and further through fixed orifice 20 under relatively constant pressure to produce filtered water flow 14. Filtered water flow 14 is sensed by water flow sensors 10 as previously described.

Simultaneous to making the water connections just described, filter element canister 60 is also configured to make an electrical connection between battery 48 and the electronic flow meter through imbedded power battery terminals 90 and imbedded power battery contacts 94 which automatically make contact when filter element canister 60 is secured in place. Battery 48 is connected to imbedded power battery terminals 90 through battery lead wires 91 which may be placed in an isolated channel running through filter element 60. A battery compartment 92 placed closer to or even adjacent to imbedded power battery terminals 90 would simplify the requirement to seal battery lead wires 91 against filter element 24.

Figure 9 is a cross sectional view of an imbedded power faucet mount water filter with an integrated filter element / housing assembly 100, making the overall configuration simpler and reducing the required water connections to one.

In this case integrated filter element / housing assembly is comprised of battery 48, an isolated battery compartment 92, filter element 24, and water flow sensors 10 all mounted within modular filter housing 102. In this case there is no requirement for an external fixed orifice 20 (reference FIG. 1) since it can become an integral part of modular filter housing 102 at filtered water exit 104.

The fact that filtered water exit 104 is an integral part of modular filter housing 102 precludes the requirement for a separate water connection at this point. Only a tap water inlet connection is required, and this is accomplished through integrated connector 110. Integrated connector 110 also contains the power connection required to connect battery 48 to the electronic flow meter. Integrated connector 110 comprises tap water inlet 96, integrated seal 112, tap water channel 113, power / water flow sensor plug 114, and power / water flow sensor receptacle 116. As integrated connector 110 is assembled, tap water inlet 96 becomes connected to tap water channel 113 and is sealed against leakage by integrated seal 112. Thus, when water flow control switch is in the correct position, tap water is diverted through tap water channel 113 and tap water inlet 96 so that it may be filtered through filter element 24.

Power / water flow sensor plug 114 also becomes connected to power / water flow receptacle 116 as integrated connector 110 is assembled. This provides power to, and connects water flow sensors 10 to, control circuit 16 which is contained in faucet mount housing 32 (reference FIG. 2). Power / water flow sensor plug 114 and power / water flow sensor receptacle 116 may contain four independent connections as follows: battery 48 positive, battery 48 negative, and two water flow sensor 10 connections. Alternatively it may contain just three independent connections if control circuit 16 is re-configured to connect one of the water flow sensor connections to either battery 48 positive or battery 48 negative.

FIG. 10 presents a detailed view of integrated connector 110. In this case the wall of tap water channel 113 has been increased in thickness such that it may contain retaining lock 120 and power / water flow sensor receptacle 116. Also, the wall of tap water inlet 96 has been increased in thickness such that it may contain power / water flow sensor plug 114 and retaining latch 122. Integrated seal 112 is integral to tap water inlet 96.

Tap water inlet 96 and tap water channel 113, and power / water flow senor plug 114 and power / water flow sensor receptacle 116 will simultaneously connect as integrated connector 110 is assembled. The integrity of the connections will be maintained by the interlocking of retaining lock 120 and retaining latch 122 until such time as retaining lock 120 is released by retaining lock release activator 124, and integrated connector 110 is pulled apart. This simple operation is all that is required to remove and replace filter element 24 and battery 48 (reference FIG. 9)

Integrated connector 110 can also be configured to communicate various filter element 24 capacities to control circuit 16, allowing control circuit 16 to set the timer presets accordingly (reference FIG. 2). Three of the four connectors in power / water flow sensor receptacle 116 will be required for filter element 24 having capacity "X", leaving a fourth connection to be used as the alternate battery 48 positive connection for a different filter element 24 having capacity "Y" (reference FIG. 9). In this manner the rated capacity of the installed filter element 24 can be determined by which pin is providing power to the control circuit 16. A logical corollary is that a lack of power on either pin means that no filter element 24 is present, and this information can be used to reset the timers.

In certain applications integrated connector 110 may be simplified by allowing one of the electrical contacts to intentionally protrude through the wall of tap water channel 113 to form one of the water flow sensors 10 The other water flow sensor 10 may be located elsewhere in the filtered water flow, most typically in filtered water outlet 12 as depicted in FIG. 2. This simplified configuration reduces the cost of integrated filter element / housing assembly since it removes one sensor, and the associated wiring, from this disposable module.

As a further safeguard against user error, it is possible that integrated connector 1 10 may contain an automatic valve that only allows water to flow through tap water channel 113 when integrated connector 110 is engaged. This would prevent the accidental release of water through tap water channel 113 should water flow control switch 44 be moved to the wrong (i.e. "filter") position after an integrated filter element / housing assembly has been removed (reference FIG. 9).

In certain designs the flow of water through tap water channel 113 may be initiated by turning integrated filter element / housing assembly 100 approximately 90 degrees, for example from a horizontal to a vertical orientation, rather than using water flow control switch 44. It should be noted that integrated connector 110 has been designed to interlock securely such that tap water channel 113 and tap water inlet 96 will rotate together, preserving the integrity of both the water and the electrical connections as the rotation takes place. The rotation of tap water channel 113 will activate a diverter mechanism to direct the flow of water through tap water channel 113 as outlined above.

In this type of "rotating" design it is possible to automatically drain tap water channel 113 by placing an air vent in the rotating valve mechanism such that tap water channel 113 is exposed to the air when the valve is in the "off' position - i.e. when it is not directing water through the filter element. This allows water flow sensors 10 (reference FIG. 1 ) to be placed in water channel 113, rather than at the filtered water exit, since water channel 113 will be drained and one or both of the water flow sensors will be exposed to air rather than water to prevent extraneous flow signals when the filter is "off. This re-location of water flow sensors 10 precludes the requirement for their connection through integrated connector 110. Power may be supplied from a battery integral to the filter element (i.e. imbedded power) or from a battery contained in the faucet mount housing 32 (reference FIG. 2).

FIG. 11 provides an overview of an automatic dispense mechanism that might be used to improve the operation of a tap mount water filter. Current models require a two step operation since the user must first turn on the main water supply and then rotate water flow control switch 44 to direct the water through filter element 24 and out through filtered water outlet 12. Alternatively, in an imbedded power water filter, the same diversion of water flow through filtered water outlet 12 may be accomplished through electrically driven valves rather than a mechanically operated flow control switch 44. These valves may be controlled by automatic flow control lever 130 which can be actuated by simply placing a glass or other container under filtered water outlet 12. In this manner the user need only turn on the main water supply and then put the water container in place, removing one of the steps from the operation. Automatic flow control lever 130 may have a "lock" position or it may be overridden by an alternate switch to facilitate the filling of very large containers. In either case it is important that toggle type valves be used, and that the imbedded battery be used to simply trigger the valve rather than hold it open since this would consume an excessive amount of the battery's limited energy supply.

The use of automatic flow control also allows for the positive shut down of filtered water flow when the electronic flow meter provides an end-of-life signal to the user. This can simply be interconnected with the automatic flow control valve such that the valve will not function when an end-of-life signal is present. Further, in the case of an imbedded power water filter, the end-of-life signal can also trigger the depletion of the imbedded battery which will serve to disable the automatic flow control valves, due to a lack of power, and also prevent the further use of that particular filter element.

As previously noted, in some situations the water is directed through the filter and out through filtered water outlet 12 by rotating the filter cap 46 from a horizontal to a vertical position rather than using water flow control switch 44. In these cases it is possible to arrange automatic flow control lever 130 such that it will accomplish necessary rotation of filter cap 46. A spring may placed in the rotating mechanism such that filter cap 46 will automatically return to the horizontal or "off' position once the water container is removed. An interlock may also be provided to retain the spring and hold the filter cap 46 in the vertical or "on" position to facilitate the filling of large containers. From a user perspective this may be accomplished by first rotating the filter cap 46 to engage the filter and then moving filter cap 46 slightly to the left (as viewed from the front) to engage the interlock. The interlock could be released by simply tapping the filter cap 46 back to the right, at which point the spring would return the filter cap 46 to a horizontal or "off" position. Note that integrated connector 110 (reference FIG. 10) has been designed to support this type of operation. FIG. 12 shows how the electronic flow meter may be implemented in a water use appliance, in this case a refrigerator with an integrated water filter and drinking water dispenser. Chilled drinking water is dispensed by pushing water dispense actuator 130. The water is dispensed under relatively constant pressure through a fixed orifice which is integrated into filtered water outlet 132. This flow is sensed by water flow sensors 10 which are connected to an electronic flow meter. The status of the filter is communicated to the user through indicator light 26. In this case an end-of-life signal may provide a red signal to the user as well as disable water dispense actuator 130, thereby preventing further use of the filter until such time as it is replaced. The availability of power within such an appliance precludes the requirement for imbedded power within the filter element. However battery backup should be used to retain accumulator values and other status information in the event of a power failure.

FIG. 13 represents an alternative use for the electronic flow meter in an under the sink application. Operation is similar to that of a faucet mount unit except that the user indicator light attached to electronic flow meter 140 would not be visible to the user. Therefore an audible signal 142 is used to alert the user when the filter element reaches end-of-life. This signal may beep or provide some other means of suitable notification.

FIG. 14 illustrates how the electronic flow meter may be used to measure the flow of water through a pour through or pitcher type device. In this case water is poured into tap water reservoir 150 where it drains through removable filter element 152 and into filtered water reservoir 154. Filtered water is retained in filtered water reservoir 154 until such time as it is dispensed through spigot 156 which is normally actuated by the user. Water flow sensors.10 are located in spigot 156 such that they will sense the flow of water through spigot 156.

In this case the constant flow assumption is not accurate since the level of water in filtered water reservoir 154 will clearly fluctuate over time and in a non-predictable manner. Therefore the combined presence or absence of signals from high level sensors 158 and low level sensors 160 can be used calculate flow based on three representative flow rates. High flow rate will correspond to a high level of water in filtered water reservoir 154, and will be determined by positive signals from both high level sensors 158 and low level sensors 160. In a similar manner, medium flow rate will be determined by a positive signal from only low level sensors 160, and low flow rate will be determined by no signal from either sensors. The signals from the sensors may be amplified and processed as previously described.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Certain adaptations and modifications of the invention will be obvious to those skilled in the art. Therefore, the above-discussed embodiments are considered to be illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

WE CLAIM:

1. An electronic flow meter comprising: a) a fluid conduit having a capacity rated element end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on said inner side, said sensors in communication with said power source, and said sensors adapted to allow an electrical current from said power source to flow between said sensors when a fluid is between said sensors; d) a signal processor in communication with said sensors, said signal processor adapted to increment a flow value temporally corresponding to a communication of said electrical current flow between said sensors; e) an indicator in communication with said power source and in communication with said signal processor; wherein said signal processor is configured to activate said indicator to indicate the status of said flow value relative to a set value.

2. An electronic flow meter as claimed in claim 1 , further comprising a pressure sensor located in said conduit, said pressure sensor in communication with said signal processor, said pressure sensor adapted to determine a quantity of pressure on said pressure sensor and to communicate a flow rate signal corresponding to said quantity of pressure to said signal processor, and said signal processor is adapted to combine said flow rate signal with said electric current flow between said sensors to determine said flow value.

3. An electronic flow meter as claimed in either claim 1 or claim 2, further comprising a valve in communication with said power source and in communication with said signal processor, wherein said signal processor is configured to signal said valve to substantially close when said flow value exceeds said set value.

4. An electronic flow meter as claimed in any one of claims 1 to 3, further comprising a real time accumulator adapted to accumulate time since a first installation of a capacity rated element, said real time accumulator in communication with said signal processor, and said signal processor is adapted to activate said indicator when said accumulated time exceeds a set value.

5. An electronic flow meter as claimed in claim 4, further comprising a reset sensor in communication with said signal processor, and said reset sensor is positioned such that inserting a capacity rated element into said conduit actuates said reset sensor.

6. An electronic flow meter as claimed in claim 5, wherein said reset sensor is adapted to reset said real time accumulator when said reset sensor is actuated.

7. An electronic flow meter as claimed in either claim 5 or claim 6, wherein said reset sensor is adapted to reset said flow value when said reset sensor is actuated.

8. An electronic flow meter as claimed in any one of claims 1 to 7, further comprising a signal amplifier communicating between at least one of said sensors and said signal processor.

9. An electronic flow meter as claimed in any one of claims 1 to 8, wherein said fluid flow sensors are located proximal to said output aperture end.

10. An electronic flow meter as claimed in claim 2, further comprising a constricted portion of said conduit located between said capacity rated element end and said fluid flow sensors, and wherein said pressure sensor is located in said conduit between said constricted portion and said capacity rated element end.

11. An electronic flow meter as claimed in any one of claims 1 to 10, wherein said signal processor is adapted to detect the presence of different capacity rated elements or to detect various characteristics of the capacity rated element by detecting at least one of physical, magnetic or other properties of the capacity rated element.

12. An electronic flow meter as claimed in any one of claims 1 to 11 , wherein said signal processor is configured to activate said indicator at two or more set values, and said indicator is configured to indicate two or more indications corresponding to said two or more set values.

13. An electronic flow meter as claimed in any one of claims 1 to 12 wherein said signal processor is configured to activate said indicator for a set period of time after flow between said sensors has stopped.

14. An electronic flow meter as claimed in any one of claims 1 to 13, wherein said signal processor is configured to detect a low power status of said power source and to signal said indicator, and said indicator is configured to indicate said low power status.

15. An electronic flow meter comprising: a) a fluid conduit having a capacity rated element end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on said inner side, said sensors in communication with said power source, and said sensors adapted to allow an electrical current from said power source to flow between said sensors when a fluid is between said sensors; d) a signal processor in communication with said sensors, said signal processor adapted to increment a flow value in response to a communication of said electrical current flow between said sensors; e) a valve in communication with said power source and in communication with said signal processor, wherein said signal processor is configured to signal said valve to close when said flow value exceeds said set value.

16. A capacity rated element assembly for use with an electronic flow meter apparatus, said capacity rated element assembly comprising: a) a power source located in said capacity rated element; b) connections in communication with said power source, said connections configured to communicate with said electronic flow meter apparatus to supply power to said apparatus.

17. A capacity rated element assembly as claimed in claim 16, further comprising an actuator adapted to reset said flow value when said capacity rated element is installed to said electronic flow meter apparatus.

18. A capacity rated element assembly as claimed in claim 16 or 17, wherein said capacity rated element is adapted to communicate various characteristics of said capacity rated element assembly to the electronic flow meter apparatus through at least one of physical, magnetic or other properties of the capacity rated element assembly.

19. A capacity rated element assembly as claimed in any one of claims 16 to 18, wherein said capacity rated element assembly contains a valve in communication with said signal processor, wherein said signal processor is configured to signal said valve to substantially close when said flow value exceeds said set value, and said valve, once closed, provides a visible signal indicating its closure.

20. An electronic flow meter as claimed in claim 5, wherein said signal processor is configured such that, upon activating said reset sensor, said signal processor sends said indicator a flush signal, and said indicator is configured to display a flush indicator.

21. An electronic flow meter as claimed in claim 20, wherein said signal processor is configured such that said flush indicator is displayed for an amount of time corresponding to a set amount of flow.

22. An electronic flow meter as claimed in any one of claims 1 to 3, further comprising a real time accumulator adapted to accumulate time since an occurrence of said fluid flow, said real time accumulator in communication with said signal processor, and said signal processor is adapted to activate a flush signal on said indicator when said time since an occurrence of said fluid flow exceeds a set value.

23. An integrated capacity rated element assembly comprising a housing containing: a) a fluid conduit having a connection end, an output aperture end, and an electrically insulated inner side; b) a power source; c) at least two conductive fluid flow sensors located on said inner side, said sensors in communication with said power source, and said sensors adapted to allow an electrical current from said power source to flow between said sensors when a fluid is between said sensors; d) a capacity rated element located in said conduit between said connection end and said fluid flow sensors; and e) a signal processor connection located proximal to said connection end, said signal processor connection in communication with said power source and with said fluid flow sensors.

24. An integrated capacity rated element assembly as claimed in claim 23, further comprising a dry conduit for communication from said power source and said fluid flow sensors to said signal processor connection.

25. An integrated capacity rated element assembly as claimed in either claim 23 or 24, further comprising a fastener proximal to said connection end, said fastener adapted for releasably securing said assembly to a connection.

26. An integrated capacity rated element assembly as claimed in any one of claims 23 to 25, further comprising a lever and a valve actuated by said lever, and said valve has a first position for directing the flow of fluid through said capacity rated element and a second position for directing the flow of fluid away from said capacity rated element.

27. An integrated capacity rated element assembly as claimed in claim 26, wherein said lever rotates said integrated capacity rated element assembly to actuate a valve proximal to said connection end, said valve having a first position for directing the flow of fluid through said capacity rated element and a second position for directing the flow of fluid away from said capacity rated element, said fastener adapted for releasably securing said assembly to said valve.

28. An integrated capacity rated element assembly as claimed in claim 26 or 27, further comprising an air vent in flow communication with said fluid flow sensors and wherein a rotation of said integrated capacity rated element assembly opens and closes said air vent.

29. An integrated capacity rated element assembly as claimed in any one of claims 23 to 28, wherein said fluid conduit has a constricted portion.

30. An integrated capacity rated element assembly as claimed in any one of claims 24 to 29, wherein said dry conduit further contains multiple subsets of connectors, said subsets corresponding to multiple integrated capacity rated elements of different capacities, and said assembly is configured to connect a unique subset of connectors to a corresponding set of signal processor connectors.

31. An integrated capacity rated element assembly as claimed in any one of claims 23 to 30, wherein at least one of said connectors extends into the fluid conduit to form one of said sensors.

32. An integrated capacity rated element assembly as claimed in any one of claims 23 to 31 , wherein said power source is intentionally drained by said signal processor, when a set value for said capacity rated element has been exceeded.

33. An integrated capacity rated element assembly comprising a housing containing: a) a fluid conduit having a connection end and an output aperture end; b) a power source; c) a conductive fluid flow sensor connection located proximal to said connection end, said fluid flow sensor connection in communication with said power source; and d) a capacity rated element located in said conduit between said connection end and said output aperture end.

34. An integrated capacity rated element assembly as claimed in claim 33, further comprising a dry conduit for communication from said power source to said fluid flow sensor connections.

35. An integrated capacity rated element assembly as claimed in either claim 33 or 34, further comprising a fastener proximal to said connection end, said fastener adapted for releasably securing said assembly to a connection.

36. An integrated capacity rated element assembly as claimed in any one of claims 33 to 35, further comprising a lever and a valve actuated by said lever, and said valve has a first position for directing the flow of fluid through said capacity rated element and a second position for directing the flow of fluid away from said capacity rated element.

37. An integrated capacity rated element assembly as claimed in claim 36, wherein said lever rotates said integrated capacity rated element assembly to actuate a valve proximal to said connection end, said valve having a first position for directing the flow of fluid through said capacity rated element and a second position for directing the flow of fluid away from said capacity rated element, said fastener adapted for releasably securing said assembly to said valve.

38. An integrated capacity rated element assembly as claimed in claim 36 or 37, further comprising an air vent in mechanical communication with said integrated capacity rated element assembly and wherein a rotation of said integrated capacity rated element assembly opens and closes said air vent.

39. An integrated capacity rated element assembly as claimed in any one of claims 33 to 38, wherein said fluid conduit has a constricted portion.

40. An integrated capacity rated element assembly as claimed in any one of claims 34 to 39, wherein said dry conduit further containing multiple subsets of connectors, said subsets corresponding to multiple integrated capacity rated elements of different capacities, and said assembly is configured to connect a unique subset of connectors to a corresponding set of signal processor connectors.

41. An integrated capacity rated element assembly as claimed in any one of claims 33 to 40, wherein at least one of said connectors extends into the fluid conduit to form one of said sensors.

42. An integrated capacity rated element assembly as claimed in any one of claims 33 to 41 , wherein said power source is intentionally drained by said signal processor, when a set value for said capacity rated element has been exceeded.

43. An integrated capacity rated element assembly as claimed in any one of claims 23 to 42, wherein said capacity rated element is a filter.

44. An electronic flow meter as claimed in any one of claims 1 to 15 or 20 to 22, wherein said capacity rated element is a filter.

45. A capacity rated element assembly as claimed in any one of claims 16 to 19, wherein said capacity rated element is a filter.

46. An electronic flow meter as claimed in any one of claims 1 to 15 or 20 to 22 wherein said signal processor is adapted to communicate with the control processors of an appliance in which said electronic flow meter is installed.

47. A method for indicating the status of a capacity rated element, comprising the steps of:

(a) registering the installation of a capacity rated element;

(b) resetting an accumulator upon said registering of installation;

(c ) detecting a flow of fluid in association with said capacity rated element;

(d) incrementing a time value of said accumulator while said detecting of flow;

(e) determining whether said used time value is greater than a set value; and

(f) actuating an indicator when said used time value is greater than a set value.

48. A method as claimed in claim 47 further comprising, after step (d), incrementing a real time value of a real time accumulator; determining whether said real time value is greater than a real time set value; and actuating an indicator when said real time value is greater than a real time set value.

49. A method as claimed in claim 47 or 48 further comprising several set values and at least one indicator.

50. A method as claimed in any one of claims 47 to 49 further comprising, after step (e), closing a valve when one of said time values is greater than a corresponding set value.

51. A method as claimed in any one of claims 47 to 50 further comprising, after step (a), determining whether the power level of a power source is below a set power value; and actuating an indicator when said power level is below said set power value.

52. A method as claimed in any one of claims 47 to 51 further comprising, after a cessation of flow, accumulating a flush time value; and determining whether said flush time value is greater than a set flush value; and actuating an indicator when said flush time value is greater than a set flush value.

53. A method as claimed in any one of claims 47 to 52 further comprising, during step (c) sensing a pressure of said fluid; and during step (d) modulating said incrementing by a factor related to said pressure to correspond said incrementing to an actual flow rate.

54. A method as claimed in any one of claims 47 to 53 further comprising, after step (a), resetting said set values to correspond to a specific capacity rated element.

55. An integrated capacity element assembly as claimed in any one of claims 23 to 42 wherein said power source may be electrical or mechanical.

56. A capacity rated element assembly as claimed in any one of claims 16 to 19 wherein said power source may be electrical or mechanical.

57. An integrated capacity rated element assembly as claimed in any one of claims 33 to 42 wherein said power source may be located external to said integrated capacity rated element assembly.

58. A pitcher apparatus comprising a pitcher containing an electronic flow meter of claim 1.

59. A pitcher apparatus as claimed in claim 58, further comprising high level detectors for detecting a high level of fluid in said pitcher apparatus and low level detectors for detecting a low level of fluid in said pitcher and fluid flow sensors located at the fluid outlet of said pitcher, said level detectors in communication with said signal processor, and said signal processor is adapted to combine said communications from said level detectors with said electric current flow between said fluid flow sensors to determine said flow value.

60. An electronic flow meter as claimed in any one of claims 1 to 15 or 20 to 22 further comprising a flag actuated on the first use of said capacity rated element to prevent reuse of said capacity rated element.