US3582613A - Fluid-heating device - Google Patents

Abstract

A fluid-heating device comprising a casing, outer and inner chambers therein, a hollow metal core about which spaced turns of Teflon-coated wire is wound and which wire constitutes a heater for raising the temperature of fluid flowing into the inner chamber to a preset range of temperature, a thermistor for sensing temperature of fluid discharged at the top of and from the inner chamber and being adapted for connection to an electrical circuitry which opens and closes a fluid valve associated with an inlet port for the outer chamber. The changers are separated from each other and a filter is provided about the core for preventing foreign material, dirt and the like from passing from the outer to the inner chamber. The core is provided with fluted passageways for upward circulation of the filtered water in the inner chamber.

Description

United States Patent {72] Inventor Othmar W. Pies 200 W. Galbraith Road, Cincinnati, Ohio 45215 [21] Appl. No. 766,789

[22] Filed Oct. 11, 1968 [45] Patented June 1, 1971 [54] FLUID-HEATING DEVICE 7 Claims, 8 Drawing Figs.

[52] U.S. Cl 219/307, 165/119, 219/308, 219/331, 219/334, 219/381, 222/146 [51] Int. Cl F24h 3/00 [50] Field 01 Search 219/296- [56] References Cited UNITED STATES PATENTS 564,657 7/1896 Stiebel 219/319X 793,118 6/1905 Wright et al. 219/299X 894,323 7/1908 l-lolt 219/307 10/1913 .Ioerin et a1. 219/296X 1,335,020 3/1920 Papini 219/333X 2,103,434 12/1937 Pennebaker 2l9/381(UX) 2,635,174 4/1953 Kasten 219/381(UX) 3,235,084 2/1966 King et al.... 219/381(UX) Primary Examiner-A. Bartis Attorney-Pearce 8L Schaeperklaus ABSTRACT: A fluid-heating device comprising a casing, outer and inner chambers therein, a hollow metal core about which spaced turns of Teflon-coated wire is wound and which wire constitutes a heater for raising the temperature of fluid flowing into the inner chamber to a preset range of temperature, a thermistor for sensing temperature of fluid discharged at the top of and from the inner chamber and being adapted for connection to an electrical circuitry which opens and closes a fluid valve associated with an inlet port for the outer chamber. The changers are separated from each other and a filter is provided about the core for preventing foreign material, dirt and the like from passing from the outer to the inner chamber. The core is provided with fluted passageways for up ward circulation of the filtered water in the inner chamber.

F74 TEE PATENTEI] JUN 1 l9?! SHEET 2 [IF 2 FLUID-HEATING DEVICE BACKGROUN D OF THE INVENTION I Field ofthe Invention The field of art to which this invention is most likely to pertain is generally located in the class of apparatus relating to fluidor water-heating devices.

2. Description of the Prior Art Heating apparatuses, the art to which this invention most likely pertains, are disclosed in the following US. Pats.: Nos. 793,118; I,335,020;3,l97,6l3;and 3,247,359.

SUMMARY This invention relates to a device for instantaneously heating fluid, and particularly relates to a water-heating device through which tap water may be fed, circulated therethrough, and from which hot water is instantaneously discharged.

An object of this invention is to provide for a novel fluidheating device.

Another object of this invention is to provide for a device instantaneously heating water and which is readily adaptable for use in other environments, an example of which is in the making of hot liquid coffee.

A further object of this invention is to provide for a device which eliminates the provision for storing water prior to heating thereof.

Another object of this invention is to provide for an efficient and economical device for heating fluid, in particular, water.

A still further object of this invention is to provide for a wide adaptability in actual application, such as in coffee makers, of the invention due to its relatively small size.

A further object of this invention is to provide for the substantial elimination of liming and other deposits because of the controlled and limited amount of water circulating through the heating portions of the device.

Another object of this invention provides for negligible maintenance on the device which has no moving parts therein.

A still further object of this invention provides for manifolding these devices together for increasing total volume of heated water.

Another object of this invention provides for absence of the process of steaming or vaporization of the fluid while in the device, thereby eliminating maintenance and inefficiency otherwise developed as a result of collection of deposits of foreign matter and the like.

Briefly, this invention provides a fluid heater which includes in combination, a sealed casing having an outer chamber and an inner chamber. A metallic core separates the chambers and is provided with helically wound serrations on the periphery thereof. A plurality of fluted surfaces formed longitudinally in such periphery provide passageways for circulation of fluid. A heater element is mounted about said serrations. Spaces are provided between turns of said heater element for passage of fluid from the outer chamber into the passageways. A filter is mounted about said metallic core and the heater element. Fluid enters through an inlet port in the outer chamber, and passes from the passageways into the inner chamber to be discharged through an outlet port of the inner chamber.

These and other objects and advantages of the invention will become more apparent upon a full reading of the following description, appended claims thereto, and the drawing comprising two sheets.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational sectional view of a device embodying the invention.

FIG. 2 is a view taken on line 2-2 of FIG. 1.

FIG. 3 is a view taken on line 3-3 of FIG. 1.

FIG. 4 is a view taken on line 4-4 of FIG. 1.

FIG. 5 is a fragmentary exploded view of a portion of a device embodying the invention.

FIG. 6 is a fragmentary exploded view of another portion of a device embodying the invention.

FIG. 7 is a fragmentary exploded view of still another portion of a device embodying the invention.

FIG. 8 is a schematic diagram of an electrical circuit suitable for use in operation ofa device embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in which reference characters therein correspond to like numerals hereinafter in the following description, reference character 20 generally represents a device embodying the invention. Device 20 comprises a hollow casing 21 having a base 22 and a cone-shaped top 23 suitably tightly secured to casing 21 and sealed thereto by means of O-rings 24 and 25, respectively, as shown in FIG. 1. One form of securing casing base 22 and top 23 to casing 21 is shown in FIG. 1, wherein a frame comprising a pair of elongated bolts 26, 27 extending through a cross frame member 28 mounted over and seated upon top 23 is held in stationary position to a flat support member 29 by means of nuts 30 in threaded engagement to bolts 26, 27 and which are tightened against flat support member 29. Member 29 includes a rim 31 for seating upon a shoulder 32 provided in base 22. Such securement provides for ready disassembly and assembly of device 20.

An inlet port 33 (FIGS. 1, 3) is securely mounted to casing 21, preferably transversely to and midway of the latters length, for introduction of fluid into an outer chamber 34 of device 20, while an outlet or discharge port or conduit 35 is provided for an inner chamber 36 of device 20. Port or conduit 35 is disposed in and extends through the center of coneshaped top 23 for delivery of heated fluid from inner chamber 36 to a remote or other desired point of further discharge therefrom. An O-ring 37 seals port or conduit 35 in top 23 to prevent leakage of fluid thereat, while a washer element 38 may be mounted above O-ring 37 and below crossmember 28 to prevent damage thereto in the assembly of device 20.

An aluminum core 39 is disposed within, spaced from and longitudinally of casing 21, its lower end being seated in an annular recess 40 in base 22 and its upper end being supported within a ring 41 mounted about core 39. The inner diameter of ring 41 along its upper rim, FIG. 1, is of a smaller dimension than the outer diameter of core 39 whereby ring 41 does not slide down upon core 39 and the upper terminal extremity of ring 41 seats in a slot 42 formed about the underside of coneshaped top 23, upon tight assembly of device 20.

Aluminum core comprises a cylindrical tube having a plurality of parallel fluted surfaces 43 extending longitudinally of its periphery and a corresponding hole 44 connecting each fluted surface 43 to the interior bore 45 of core 39. Holes 44 are provided adjacent the lower end of core 39, as shown in FIG. 1. A series of helically wound serrations 46 are provided around the periphery of core 39 on the surfaces thereof separating fluted surfaces 43 from each other, as shown in FIGS. 1 and 5. Coiled about core 39 and in serrations 46 is a Teflon-coated eIectricalcurrent-conducting wire 47 whose ends 48, 49 (FIG. 6) begin and return to their respective connections with a pair of contacts 50, 51, respectively, securely mounted in base 22 for connection to a suitable source of electrical energy. An aperture 52 is provided through core 39 adjacent the lower limit of use of serrations 46 for egress of wire 47 from its connection with one of contacts 50, 51 to the exterior of core 39 for winding upwardly therearound in serrations 46, and an aperture 53 (FIG. 1) is provided through core 39 adjacent the upper limit of use of serrations 46 for ingress of wire 47 to the interior bore 45 of core 39 for return and connection to the other of contacts 50, 51, as shown in FIGS. 1 and 6. It may be noted here that the length of ring 41 extends downwardly of core 39 to hole 53. The upper extremity of the winding of wire 47 at the limit of hole 53, overlap ofa filter 66 and the clampdown feature of top 23 upon ring 41 maintain proper position of ring 41 on core 39 during and after assembly of device 20.

FIG. 6 illustrates in detail a preferred connection of the ends of wire 47 with its contacts 50, 51. Each contact 50, 51 includes a brass T-head portion 54 fitted to a hole 55 bored in base 22. T-head 54 is secured therein by means of a brass retainer sleeve 56 threadedly engaging base 22. Each end of wire 47 extends through a hole provided in base 22 for attachment to its contact 50, 51, and an Allen screw 57 is threaded laterally into T-head 54 whereby each end 48, 49 of wire 47 is secured to its respective brass contact 50, 51. An ring 58 and washer 60 are disposed in a reduced portion of hole 55, as shown in FlG. 6, and are mounted about the Teflon coating 62 on wire 47, whereby the interior of casing 21 is sealed and electrical elements 47, 50, 51 are insulated from fluid contained in device 20.

A porous twill tape 64 is tightly wrapped helically about wound wire 47 and core 39. Filter 66, preferably of synthetic material, is mounted in turn over tape 64. Wound tape 64 cooperates with ring 41 and a second ring 65 seated in annular base recess 40 about serrated core 39 for separating inner chamber 36 from outer chamber 34 in addition to functioning with filter 66 to prevent foreign particles, dirt and the like from clogging a spacing 68 of one twenty-thousandth inch provided between each turn of coated wire 47 wound on serrations 46 for passage of fluid into passageways 70 formed by fluted surfaces 43. Filter 66 and tape 64 further function to minimize circulation of fluid on the outside of coils 47, i.e., they equalize flow of fluid or water through each spacing 68. The upper limit of second ring 65 abuts lower hole 52 (in core 39) through which wire 47 egresses for winding in serrations FIG. 7 illustrates a temperature-compensating resistor element 75, known as a thermistor in the art, and which is utilized for sensing the temperature of fluid discharged at conduit 35. Thermistor 75 preferably comprises a glass probe 76 securely mounted in top 23 by means of silicon cement 77 sealing it in a hole in top 23 through which it extends. A pair of leads 78, 79 (FIGS. 7, 8) incorporate thermistor 75 to within an electrical circuitry 80 (FIG. 8) utilizable for heating wire 47 and operatively opening and closing a solenoid valve 82 through which fluid or water flows to inlet port 33 of device 20, thereby maintaining a desired temperature for fluid or water discharging through conduit 35. FIG. 8 illustrates schematically a circuit for maintaining fluid temperature within a preset range of values. However, it should be understood that other electrical circuits may be utilized also in effecting control of fluid temperature, understanding that the inventive concept does not extend beyond device 20.

Current lines 78, 79, in which thermistor 75 is disposed, are in essence one side of a sensing bridge 84 included in general circuit 80. Sensing bridge 84 is balanced as long as the tem' perature of the discharging fluid sensed by thermistor 75 is, say, l90 F. Should bridge 84 become unbalanced, the voltage output therefrom is either increased or reduced. Should such temperature fall below 190 F., such voltage output of bridge 84 becomes negative and its collector voltage drops to a value whereby an electronic switch of a silicon control rectifier (SCR) unit 86 connected to bridge 84 does not trigger or close. As a consequence, no current flows along current line 88 to one side of solenoid valve 82 and valve 82 thus is mechanically in closed position. Should temperature rise above 190 F., the resistance of thermistor 75 falls to a very low value, the bridge 84 again becoming unbalanced but with a positive voltage output sufficient to feed an amplifier 90 connecting SCR unit 86 with bridge 84.

Amplifier 90 comprises two stages: a differential amplifier with transistors and a common emitter amplifier. A voltage signal of sufficient value from sensing bridge 84 is sufficient to cut off such transistors, thereby raising the collector voltage of bridge 84 and changing the value of capacitance in a capacitor C. When such capacitance reaches a high enough value, increased voltage in SCR unit 86 triggers its switch thereby sup plying current through line 88 to solenoid valve 82, opening the latter to provide for flow of fluid therethrough to inlet port 33 of device 20. Should temperature of the fluid again fall below 190 F., output voltage of bridge 84 is reduced, the transistors of the differential amplifier of amplifier 90 become saturated, and the collector voltage of bridge 84 drops, thereby reducing the voltage in SCR unit 86 to a degree where its switch does not trigger current to solenoid valve 82, thus valve 82 closing.

It should now be apparent that when the temperature of the fluid being discharged at port 35 is above l90 F., the function of thermistor 75 in circuitry maintains solenoid valve 82 in an open condition.

A temperature-limiting circuit may be included in circuitry 80 for closing valve 82 when the temperature of the fluid at port 35 exceeds a predetermined value such as, say, 210 F.

When an adjustable resistor or resistance 92 in such circuit is so adjusted that voltage output in an SCR unit 96 including an electronic switch is reduced, no current flows through line 94 to coiled wire or heater element 47. Resistor 92 may be manually adjustable for increasing or reducing its resistance whereby voltage output from amplifier 90, which is indicative of the temperature of the fluid at port 35 sensed by thermistor 75, be of too great a value, say, of a value correlated to a temperature of 210 F., then resistor 92 reduces the voltage output of SCR unit 96 thereby opening the electronic switch in SCR unit 96 in line 94 leading to coiled wire 47, in the same manner as reduction of voltage in sensing bridge 84 opens the electronic switch in SCR unit 86.

A timer circuit including a timer 98, operating offa l lS-volt AC conventional source, may be included in a portion of circuitry 80 in which current is fed to coiled wire 47. Such time circuit is basically one in which capacitors are continually charging and dissipating, thus increasing and reducing voltage therethrough. By setting timer 98 to a desired length of time, say, 1 to 3 minutes, current from a ll5-volt AC source 100 is supplied for such time setting to coiled wire or heater 47 through line 94. Timer 98 becomes operative upon the fluid temperature at port 35 falling below, say, l F. However, no timing action of timer 98 occurs when such temperature is above 190 F. Controls for carrying out the function of timer 98, as well as for designing the characteristics of the components of the other electrical elements outlined above are able to be developed by one skilled in the electronic circuit design art, and it should be understood that the disclosure of the schematic illustrated in FIG. 8 does not constitute a part of the invention claimed herein, but is included merely to show one environment to which device 20 is readily adaptable.

OPERATION A main electric switch (not shown) in the ll5-volt AC source is closed, thereby energizing one side of solenoid valve 82 through a line 102, energizing timer 98 in the timer circuit and supplying current to coiled wire or heater 47 through SCR unit 96 and line 94. When water about thermistor 75 attains a temperature of F., timer 98 is inactivated. The sensing by thermistor 75 of a temperature higher than 190 F. transmits a signal to the other side of valve 82 through sensing bridge 84, amplifier 90 and SCR unit 86, thereby opening valve 82 and thus providing for flow of water into inlet port 33 of device 20. Water passes from outer chamber 34 into inner chamber 36 via metering thereof through filter 66 and twill or porous tape 64, into spacings 68 and passageways 70, and through apertures 44 from bore 45 of core 39 to passageways 70, it being exposed to heated coiled wire or heater 47, causing the water to flow upwardly along passageways 70 to discharge port 35.

Thus, temperature of the water is heated to the desired level and the range of the temperature of water being discharged at port 35 is controlled by the temperature-limiting circuit thus limiting the degree of temperature of discharged water from device 20.

When fluid or water temperature exceeds, say, 210 F., line 94 becomes nonconductive by operation of the temperaturelimiting signal or circuit. Valve 82 nevertheless remains open, continuing to provide for introduction of cooler water into device 20, thereby regaining temperature conditions of the circulating water to within the preset range provided by circuitry 80.

Should thermistor 75 sense an abnormally low temperature for the discharging water, below l90 F., line 88 becomes nonconductive and valve 82 closes until heated wire 47 raises the temperature of the upwardly circulating water, say, to 190 F. again. Valve 82 then again opens.

A pressure regulator (not shown) is preferably series-connected to valve 82 for controlling the pressure of fluid or water flowing therethrough to a preferred degree.

Calibration of circuitry 80 may be monitored by a visual signal (not shown) such as a l l-v. lamp shunted across valve 82, whereby its open or closed condition, which reflects the preset range of temperatures, may be observable and controlled.

An advantage not apparent in prior art devices providing for heating of wateror the like is found in the purpose of holes 44 in core 39. Holes 44 together with internal bore 45 provide for displacement of water throughout inner chamber 36 during operation of device 20, thereby preventing steaming or vaporizing of water in device 20 before discharge of the heated fluid. Consequently, no liming or other deposits occurred. A clean and reliably efficient operation results, as practice of the invention indicates.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art to which it pertains, or with which it is most nearly connected, such exemplification including what is presently considered to represent the best embodiment of the invention. However, it should be clearly understood that the above description and illustrations are not intended to unduly limit the scope of the appended claims, but that therefrom the invention may be practiced otherwise than as specifically described and exemplified herein, by those skilled in the art, and having the benefit of this disclosure.

Therefore, what-l claim as patentably novel is:

1. A fluid-heating device comprising in combination,

a sealed casing having a top and base,

a metallic core disposed in said casing and having a bore communicating with the exterior of the core,

helical serrations on the external periphery of said core,

a plurality of fluted surfaces formed longitudinally in said external periphery thereby providing for passageways for circulation of fluid,

a helically wound heating element mounted about said serrations,

a spacing being provided between adjacent turns of said heating element for passage of fluid into said passageways,

means for energizing the heating element,

a filter coextensive in length with the heating element mounted about said metallic core and heating element,

there being an inner chamber inside the bore of the core and an outer chamber inside the casing surrounding the filter, an inlet port to the outer chamber,

there being fluid flow communication means between the passageways and the interior of the core, and

an outlet port from the inner chamber,

whereby fluid flowing through said inlet port, through said outer chamber, filter, and each spacing and passageway may be instantaneously heated before discharge at said outlet port.

2. The device of claim 1 including a porous tape wrapped about said heat-conducting element and disposed between such element and said filter, and a pair of rings respectively seated in said top and base mounted about said core and to which said tape is attached 3. The device of claim 1 in which the fluid flow communication between said assageways and bore is'forrned by at least one hole 15 provi ed in said core between said passageways and bore.

4. The device of claim 3 wherein the heating element is electrically energized and electrical contact means for said heating element is mounted in said casing.

5. An instantaneous heating device for a fluid comprising a sealed casing defining an outer chamber about a metallic core having a bore forming an inner chamber communicating with the exterior of the core,

a plurality of fluted surfaces formed longitudinally in the external periphery of said core to define passageways extending along the external periphery;

helically disposed serrations formed on such periphery,

electrical heating means wound about said serrations and electrically insulated from the core and having spacing between adjacent turns thereof and adapted for connection to an electrical source,

means including a filter positioned about said heating means,

an inlet port for said casing connected to said outer chamber, there being fluid flow communication means between the passageways and the interior of the core, and

an outlet port for said casing connected to said inner chamber,

whereby water passing from said outer chamber into said inner chamber is metered through said means including said filter into and through said spacing for instantaneous heating thereof, and circulating toward and being discharged from said outlet port.

6. The device of claim 5 in which said means includes a porous tape wrapped about said heating means and disposed between said heating means and said filter, and a pair of rings respectively seated in the top and base of said sealed casing and to which said tape is attached.

7. The device of claim 5 in which at least one hole is provided in the wall of said core for providing said communication between its bore and said passageways.

Claims (7)

1. A fluid-heating device comprising in combination, a sealed casing having a top and base, a metallic core disposed in said casing and having a bore communicating with the exterior of the core, helical serrations on the external periphery of said core, a plurality of fluted surfaces formed longitudinally in said external periphery thereby providing for passageways for circulation of fluid, a helically wound heating element mounted about said serrations, a spacing being provided between adjacent turns of said heating element for passage of fluid into said passageways, means for energizing the heating element, a filter coextensive in length with the heating element mounted about said metallic core and heating element, there being an inner chamber inside the bore of the core and an outer chamber inside the casing surrounding the filter, an inlet port to the outer chamber, there being fluid flow communication means between the passageways and the interior of the core, and an outlet port from the inner chamber, whereby fluid flowing through said inlet port, through said outer chamber, filter, and each spacing and passageway may be instantaneously heated before discharge at said outlet port.

2. The device of claim 1 including a porous tape wrapped about said heat-conducting element and disposed between such element and said filter, and a pair of rings respectively seated in said top and base mounted about said core and to which said tape is attached

3. The device of claim 1 in which the fluid flow communication between said passageways and bore is formed by at least one hole is provided in said core between said passageways and bore.

4. The device of claim 3 wherein the heating element is electrically energized and electrical contact means for said heating element is mounted in said casing.

5. An instantaneous heating device for a fluid comprising a sealed casing defining an outer chamber about a metallic core having a bore forming an inner chamber communicating with the exterior of the core, a plurality of fluted surfaces formed longitudinally in the external periphery of said core to define passageways extending along the external periphery, helically disposed serrations formed on such periphery, electrical heating means wound about said serrations and electrically insulated from the core and having spacing between adjacent turns thereof and adapted for connection to an electrical source, means including a filter positioned about said heating means, an inlet port for said casing connected to said outer chamber, there being fluid flow communication means between the passageways and the interior of the core, and an outlet port for said casing connected to said inner chamber, whereby water passing from said outer chamber into said inner chamber is metered through said means including said filter into and through said spacing for instantaneous heating thereof, and circulating toward and being discharged from said outlet port.

6. The device of claim 5 in which said means includes a porous tape wrapped about said heating means and disposed between said heating means and said filter, and a pair of rings respectively seated in the top and base of said sealed casing and to which said tape is attached.

7. The device of claim 5 in which at least one hole is provided in the wall of said core for providing said communication between its bore and said passageways.

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