WO2003031018A1

WO2003031018A1 - Filter condition indicator

Info

Publication number: WO2003031018A1
Application number: PCT/EP2002/010378
Authority: WO
Inventors: Nikhileshwar Mukherjee; Ravi Kumar Dhulipala; Karam Vir Rehani; Pramod Prabhakar Walvekar
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2001-10-05
Filing date: 2002-09-12
Publication date: 2003-04-17
Also published as: RU2294234C2; CN1306984C; AR036737A1; PL368866A1; MXPA04003145A; BR0213109A; MY134292A; RU2004113372A; CN1738672A

Abstract

The invention provides a simple and cost-effective water purification system which is typically in the form of a storage filter. The system comprises at least one filter cartridge, a discharge outlet adapted to discharge filtered water, and a flow sensor arrangement adapted to sense the flow of water through the discharge outlet. The flow sensor arrangement comprises a pair of sensors arranged so that when the discharge outlet is opened and water flows through the outlet and between the sensors, the sensors become electrically connected to the electronic control panel and the water flow can be measured based on the time during which the electrical connection is established, and the status of the system (in particular the end of life of the filter cartridge) can be monitored based on the measured water flow.

Description

FILTER CONDITION INDICATOR

Field of the Invention

The present invention relates to a filter cartridge based water purification system. In particular, the invention relates to a filter cartridge based water purification system incorporating a sensor for measuring water flow through the filter cartridge and an electronic indicator for indicating the status of the system, in particular the end of life of the filter cartridge, based on the sensed water flow through the filter cartridge.

Background and Prior Art

Various systems or devices are known for monitoring the lifespan of filter cartridges for water purification.

US 4,623,451 describes a home sink mounted water purification system which incorporates a monitoring device consisting of a conductivity sensing circuit with a pair of electrodes for measuring electrical current flow. Such a device is appropriate for use in a purification system which purifies water through reduction of dissolved solids, since the presence of dissolved solids will govern the conductivity of water. The device has limitations in that it cannot function in a water purification system where the purification is carried out not by reduction of dissolved solids but by means of, for example, a biocide which would not have any influence on the conductivity of water. In the system of US 4,623,451, rotation of the knob of the faucet mechanically establishes contact between the electrodes of the monitoring device by means of two fingers provided in the faucet. The electrodes are always submerged in water. However, the electrodes only get charged when the knob on the faucet is turned to an "on" position thereby enabling the mechanical contact of the electrodes. The system also requires a flow limiter to deliver water at a predetermined constant flow rate under normal operating pressure. A further limitation of the system is that it assumes an uninterrupted flow of water through the faucet whenever the valve is on. Even if there were no water flowing through the faucet, based on the position of the knob, the control circuit would keep monitoring the time, which could lead to errors .

US 5,328,597 discloses the use of a programmed integrated circuit to monitor the number of fills of water into a purification device. The monitoring unit provides an audio signal to warn the user that the device is nearing the end of its useful lifespan after the predetermined numbers of fills have occurred. However, the monitoring unit proposed for the purpose involves complex multiple contacts (sensors) and involves piezo-electric transducers to produce signals which makes it complex as well as costly.

US 6,024,867 discloses a counter top water filter unit having a filter housing containing a removable cylindrical filter cartridge, and which includes an electronic display to enable the user to determine readily if the filter cartridge in within its useful life-span, nearing the end of its useful life-span, or expired. Evaluation of the life- span relies on the detection of magnetic field fluctuations due to water flow through the unit. This makes the system complex, costly and cumbersome to install and maintain. The unit requires a complex and specific filter cartridge and the evaluation of the life-span is also very complex, being based on the velocity of the water flow through the unit . In this system, every time the filter cartridge gets exhausted it has to be replaced along with the evaluation mechanism, which further adds to the cost. Also, pressure drops across the pre-filter, for example due to suspended impurities, can lead to improper evaluation of life-span.

US 5,089,133 discloses another method and apparatus to sense the condition of a filter regarding whether it has reached end of life. Specifically it monitors the end of life of an activated charcoal filter. The flow sensor is positioned between the filter and the faucet. This device also involves flow sensing by means of a magnet fixed within the module cavity. The movement of the magnet (caused by pressure differential) results in the setting up of a magnetic field around the magnet that in turn closes a switch and completes a circuit via conductors to provide an indication that water is flowing through the module. The conductors are placed side by side and connect to a printed circuit board. The placement of the conductors is towards the part of the assembly that will connect to the faucet . This system is also complex and costly to manufacture and maintain.

US 4,918,426 discloses a filtration unit having an end of life detector for the filter cartridge. It uses a pressure sensor which generates a pressure differential proportional to the volume of the fluid flow which is then converted into an electrical signal. This electrical signal is then totalised to find out the actual amount of water passing through the filter. When this flow exceeds a pre-set value, a signal is generated to show the end of life of the cartridge. The use of pressure sensors and measurement of pressure differentials again involves complex and costly technology, which is difficult to install and maintain.

It is clear from the above that while several types of systems or devices for monitoring the lifespan of filter cartridges are known, each is specifically adapted according to the particular nature of the purification system with which it is used. In particular, the known flow monitoring systems tend to be too complex or costly, or otherwise technically unsuitable, for application in simple conventional storage filters . Considering that water filters presently have extensive use which is not confined to urban locations but also extends to rural areas, it would be desirable to provide a mechanism for monitoring the lifespan of filter cartridges which is simple and cost- effective to make and easily available at affordable prices. In particular it would be desirable to provide a mechanism for monitoring the lifespan of filter cartridges which is operable through battery power so as to be usable in remote locations or rural areas where electrical power may not be readily available but there is an obvious need for safe drinking water. Objects of the Invention

The object of the present invention is to provide a water purification system which incorporates a simple and cost effective mechanism for sensing water flow and indicating the status of the system, in particular the end of life of the filter cartridge, based on the sensed water flow through the filter cartridge.

A further object of the invention is to provide a storage filter with a mechanism for monitoring the status of the storage filter, in particular the end of life of the filter cartridge, which can be located anywhere and does not involve complex installation requirements or expensive technology.

A further object of the invention is to provide a storage filter with a simple and cost effective mechanism for monitoring the status of the storage filter and providing an audible and/or visual indication of the current status, such as in particular of the end of life of the filter cartridge or other aspects of the system which are dependent on the volume of water flow.

A further object of the invention is to provide a mechanism for monitoring the status of a storage filter, in particular the end of life of the filter cartridge, which can be adapted for use in any variety of storage type water filter. A further object of the invention is to provide a mechanism for monitoring the status of a storage filter, in particular the end of life of the filter cartridge, which is based on the flow of water through the filter cartridge and which ensures that the volume flow is monitored only when water actually flows out of the filter outlet and not otherwise, thereby avoiding problems of monitoring errors.

A further object of the invention is to provide a mechanism for monitoring the status of a storage filter, in particular the end of life of the filter cartridge, which is based on the flow of water through the filter cartridge, and which enables the recordal and storage of data on the status of the storage filter, in order to facilitate the use, maintenance and servicing of the storage filter.

A further object of the invention is to provide a battery- operable mechanism for monitoring the status of a storage filter, in particular the end of life of the filter cartridge, which can be used even in remote locations where there is no power source.

A further object of the invention is to provide a mechanism for monitoring the status of a storage filter, in particular the end of life of the filter cartridge, which does not require replacement after every successive change of the filter cartridge and is operative upon change of the filter cartridge for further monitoring by simply resetting after installation of the fresh cartridge. Summary of the Invention

The present invention provides a filter cartridge based water purification system comprising at least one filter cartridge, a discharge outlet adapted to discharge filtered water, and a flow sensor arrangement adapted to sense the flow of water through the discharge outlet;

which flow sensor arrangement comprises a first sensor positioned ahead of the entry of the filtered water into the discharge outlet and a second sensor positioned at the outer end of the discharge outlet downstream of the first sensor;

the first and second sensors being operatively connected to an electronic control panel, so that when the discharge outlet is opened and water flows through the outlet and between the sensors, the sensors become electrically connected to the electronic control panel and the water flow can be measured based on the time during which the electrical connection is established, and the status of the system can be monitored based on the measured water flow.

Detailed Description and Preferred Embodiments

Preferably the filter cartridge based water purification system is in the form of a storage filter.

The discharge outlet is preferably in the form of a tap.

The first and second sensors comprising the flow sensor arrangement can suitably be any made of any conductive material such as a metal pin, electrode or wire which can establish electrical contact between the sensors and the electronic control panel by the water flow through the sensors. It is important to locate the sensors in the discharge outlet so that it is only when the filtered water actually flows out of the discharge outlet that the electronic circuit is operative to monitor the volume flow based on the time during which the water flow takes place and the electrical contact between the sensors and the electronic control panel is established. In a preferred system according to the invention, the first sensor will be located ahead of the entry of the water from the filter cartridge to the tap and second sensor will be located at the outlet of the tap to ensure that the electronic control panel is operative only when there is water flow from the system through the outlet of the tap and not otherwise.

The system of the invention is readily adaptable to any filter cartridge based water purification system comprising at least one filter cartridge and a discharge outlet adapted to discharge filtered water. The electronic control panel which is resettable can be either permanently or releasably fitted on to the system. The electronic control panel is operative on battery power and therefore can be used in remote locations where there is no power source.

In the system of the invention, the amount of purified water discharged through the tap is directly monitored by the electronic control panel and as soon as water flow is sensed, the control panel keeps a cumulative total of the time during which the water flow takes place and is sensed. A memory unit in the control panel is provided with preset values of the maximum amount that the cartridge can process and based on the cumulative value from time to time, an indicator unit on the electronic control panel will display the status of the cartridge, typically by the illumination of different coloured lights according to system status - for example, the display of a green light to indicate that the cartridge is within its predetermined/preset life span, a yellow light to indicate that the cartridge has passed its safe life span, or a red light to indicate the end of life the cartridge requiring its immediate replacement. Importantly, in the system of the invention, sensing of the water flow is effected only when there is actual water flow through the system and not merely based on opening of the tap, which may or may not discharge water and hence can lead to erroneous indications.

The electronic control panel is typically a battery operable microprocessor based circuit with a memory unit which can be fed with set data on properties of the system such as in particular the desired capacity of a filter cartridge or the desired number of uses in a filter cartridge. Such data can then be compared with actual values sensed to generate status signals. For example, the electronic control panel can display the following conditions:

water flow through the tap; status of the total quantity of water through the filter cartridge when it is approaching the end of life; status of the total quantity of water through the filter cartridge when it has exceeded the end of life; status of the battery power source when the voltage falls low.

The microprocessor circuit may also be adapted to retain the data in the event of replacement of the battery.

Advantageously, the electronic control panel may be adapted to reset after every replacement of an exhausted filter cartridge by a fresh one. This avoids the problem of dispensing with the control panel every time the filter cartridge is exhausted as is experienced in some known systems .

Preferably the data storage capabilities of the electronic control panel can be based on the following parameters:

total quantity of water through the filter cartridge at any point of time; the number of resets carried out to date; display of the unique serial number assigned to the system for traceability.

The electronic control panel is preferably provided with a visual display to indicate system status. However, alternatively or additionally, audio signal indicators can also be provided.

The electronic control panel is preferably operative by battery power so that it can be used in remote locations where a suitable power source is not available. In this case an additional indicator is preferably present for indicating the status of the battery used in the system and for indicating when the battery power is exhausted and replacement is necessary.

A specific example of a system according to the invention is illustrated in the accompanying Figures, in which:

Figure 1 is a front view of a storage filter in accordance with the present invention; Figure 2 is a front view of the tap used in the storage filter;

Figure 3 is a side sectional view of the tap used in the storage filter;

Figure 4 is an exploded view illustrating the connection of the electronic control panel and indicator unit with the tap of the storage filter;

Figure 5 is an elevational view of the tap with the indicator unit mounted thereon, and

Figure 6a, 6b and 6c are side sectional views illustrating the disposition of the sensors used to sense the flow of water through the tap .

As illustrated in Figure 1 , the storage filter of the invention comprises a chamber (FC1) having at its base a support for a filter cartridge (FC2) which extends into the second chamber (SC) . An outlet tap (TP) communicates with the second chamber (SC) for the supply of purified water. The water to be purified is fed into the first chamber (FC1) at the top by removing the lid (LD) . Thereafter, the water processed through the filter cartridge (FC2) accumulates in the second chamber (SC) as filtered water, which is discharged through the outlet tap (TP) as and when required. The electronic control panel (EC) having an indicator panel (IP) is shown mounted on the tap (TP) .

Figures 2 and 3 illustrate the tap (TP) in greater detail. As shown in these Figures, the tap (TP) has a head portion (HP) which operatively connected to the second chamber (SC) of the filter (not shown) via a tubular member (TM) and gasket and nut (GN) connection. The head portion (HP) has an outlet (OT) which is spring loaded (SL) to maintain the tap outlet closed. When required for discharge of the water through the tap, the mechanical lever (ML) is activated in the direction of arrow "A" whereby the nozzle head works against the spring to move and thereby open the tap outlet for discharge of water. As soon as such discharge of water is effected, the water flow through the tap establishes the electrical connection between the sensors and the electronic control panel to monitor the system status based on the volume of water which flows through the tap during the time that water flows between the sensors and the electronic control panel monitors such flow.

Figure 4 illustrates the press fit male and female connection of the electronic control panel and the tap head portion. While this illustration shows a releasable connection of the tap and the electronic control panel, it is also possible to have a tap with an integral electronic control panel because the electronic control panel is resettable and need not be replaced each time the filter cartridge is charged. Figures 5 and 6 show the tap and electronic control panel and the disposition of the sensors which serve to monitor the water flow volume only when there is actual flow of water and not otherwise. Figure 5 shows an elevational view of the tap with the indicator panel mounted thereon, the indicator panel having a green light (G) which indicates that the filter cartridge (FC2) is within its life span, an orange light (0) indicating that the filter cartridge is nearing the end of its life span and a red light (R) indicating that the life span of the filter cartridge is over. A battery low indicator (BL) indicating that the battery needs to be replaced is also provided for.

Figures 6a, 6b, 6c show the disposition of the sensors to co-operate with the water flow through the tap to establish electrical connection between the sensors and the electronic control panel. In order to avoid any false sensing of water flow, the sensors are positioned such that it is only when the water actually flows through the tap that the electronic control panel is activated. The first sensor (FS) is positioned in the tubular member (TM) which connects the tap (TP) to the second chamber (SC) and which normally remains immersed in water. The second sensor (SS) is positioned at the outlet of the tap such that it is only when the tap is opened and water flows from the tubular member (TM) and out of the tap outlet (OT) that the first and second sensors are electrically connected through the flow of water in order to establish operative connection with the electronic control panel (ECP) . Therefore, the amount of purified water delivered by the tap is directly a function of how long the sensors (first and second) are in electrical connection by the water flowing therebetween. Each time the sensor connection is established by the flow of water, the electronic control panel (which is a microprocessor based circuit) keeps a cumulative total value of the time, and based on the cumulative value from time to time, the indication panel of the electronic control unit will display the status of the filter cartridge. Display of a green light indicates that the filter cartridge is within its predetermined/preset life span. An orange light indicates that the filter cartridge has passed its safe life span, and a red light indicates the end of life of the filter cartridge requiring its immediate replacement . The data recording the accumulated water flow through the tap is stored/updated in the memory of the electronic control panel. After the filter cartridge is exhausted and a replacement is installed, the electronic control panel may be simply reset to once again start monitoring the volume flow and related characteristics for the fresh filter cartridge. The electronic control panel need not be replaced.

Also, as shown in Figure 5, the electronic control panel is provided with an indicator to indicate the status of the battery for possible replacement as and when required.

Claims

1. A filter cartridge based water purification system comprising at least one filter cartridge, a discharge outlet adapted to discharge filtered water, and a flow sensor arrangement adapted to sense the flow of water through the discharge outlet;

2. A water purification system according to claim 1, which is in the form of a storage filter.

3. A water purification system according to claim 1 or claim 2, in which the electronic control panel is a battery operable microprocessor based circuit with a memory unit .