US3867610A

US3867610A - Electric heating apparatus for heating a liquid by electrical conduction

Info

Publication number: US3867610A
Application number: US425078A
Authority: US
Inventors: Laythol W Quaintance
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-12-17
Filing date: 1973-12-17
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18

Abstract

Electric heating apparatus for electrically conductive fluids, particularly mineralized tap water, includes inner and outer electrodes spaced apart and concentric with one another and shaped to define an annular flow passage which converges progressively to decrease in fluid-carrying volume toward the outlet end. A separate voltage is applied to one or both of the electrodes and the casing surrounding and supporting the electrodes is of an electrically non-conductive material with a metal pipe coupled thereto at ground potential so that a separate current flow path may be established from each electrode to ground via the fluid. The inner electrode is axially adjustable to vary the size of the passage to change the heating effect. A bias member urges the inner electrode to a position of minimum spacing between electrodes and a temperature responsive device downstream of the electrodes moves the inner electrode against the bias member to automatically adjust the spacing between the electrodes in accordance with fluid temperatures to maintain a uniform heating effect. A flow responsive member automatically opens and closes the circuit to the electrodes in response to fluid flow through the flow passage and a thermal switch in power line prevents excessive heating.

Description

United States Patent 1191 11 1 3,867,610

Quaintance 1 Feb. 18, 1975 1 ELECTRIC HEATING APPARATUS FOR 481,522 6/1953 Italy 219/291 ING IQ I BY ELECTRICAL 815,368 4/1937 France 219/291 CONDUCTION Primary Exam1r1er-A. Barns [75] Inventor: c ii f Quamtance- Tahoe Attorney, Agent, or Firm-Ancel W. Lewis, Jr.

[73] Assignee: Harry M. Rubenstein, Phoenix, ABSTRACT Ariz. Electric heating apparatus for electrically conductive [22] Fied, Dec 17 1973 fluids, particularly mineralized tap water, includes inner and outer electrodes spaced apart and concen- [2l] Appl. No.: 425,078 tric with one another and shaped to define an annular flow passage which converges progressively to decrease in fluid-carrying volume toward the outlet end. [52] U.S. Cl 219/286, fizz/55329652139438? A separate voltage is pp to one or both of the [51] Int Cl H65) 3/60 electrodes and the casing surrounding and supporting [58] Fie'ld "gi the electrodes is of an electrically non-conductive ma- 338/8O 86 terial with a metal pipe coupled thereto at ground potential so that a separate current flow path may be es- [56] References Cited tablished from each electrode to ground via the fluid. The inner electrode is axially adjustable to vary the UNITED STATES PATENTS size of the passage to change the heating effect. A bias 1.l7l,929 2/1916 Cubitt -2 19/288 X member urges the inner electrode to'a position of min- Meliew t t imum spacing between electrodes and a temperature gi responsive device downstream of the electrodes moves 2403334 7/1946 z 2194291 X the inner electrode against the bias member to auto- 2444'5O8 7/1948 Homim 219/293 X matically adjust the spacing between the electrodes in 25/2133? 10/1951 Harris...:.:.:: 12.... 219/285 accordance with fluid temperatures to maintain a 2,618,732 11/1952 Bernd 219/285 x form heating effect A flow responsive member aulo' 2,748,253 5/1956 Bremer 219/285 UX matically opens and closes the circuit to the electrodes 3,796,857 3/1974 Henley et al 219/286 X in response to fluid flow through the flow passage and 3,809,856 5/1974 Wills 219/286 3 h mal switch in power line prevents excessive FOREIGN PATENTS OR APPLICATIONS heatmg- 1,033,336 4/1953 France 219/291 3 Claims, 5 Drawing Figures Will-ll IIIII/IIIIIIII IIIIIIIII/II/I' ELECTRIC HEATING APPARATUS FOR HEATING A LIQUID BY ELECTRICAL CONDUCTION This invention relates to electric heaters for heating electrically conductive fluids and more particularly to a novel and improved electric heating apparatus particularly suitable for heating electrically conductive fluids such as tap water.

A variety of electric heaters utilizing the ohmic dissipation within a fluid, and particularly water, have heretofore been provided. These heaters rely on the fact that ordinary tap water is heavily mineralized and the fact that a voltage applied to the water will cause current flow therethrough. One problem with heating apparatus of this type resides in electroplating of the electrodes and further there is difficulty in providing a uniform heating with a minimum of adjustments and control. There is also a tendency for the fluid to rapidly boil away from the electrodes.

Accordingly, it is an object of this invention to provide improved electric heating apparatus for electrically conductive fluids which is simple in construction, durable and will rapidly raise the temperature of the fluids passing therethrough in a safe and efficient manner.

Another object of this invention is to provide novel electric heating apparatus for electrically conductive fluids which always returns to a position of minimum passage width or gap and adjusts automatically to maintain uniform heating temperatures.

Yetta further object of this invention is to provide novel electric heating apparatus particularly suitable for heating tap water and the like that will operate on 110 volt or 220 volt electric systems and will prevent plating or mineralization build-up on the currentcarrying electrodes.

Still a further object of this invention is to provide novel and improved electric heating apparatus with control means for automatically turning off the electric power from a source when the fluid fluid stops and connecting power to the electrodes when fluid flow begins as well as removing the electric power when the temperature of the fluid is excessive.

Still a further object of the invention is to provide a novel and improved electric heating apparatus for fluids characterized by inner and outer electrodes which define a converging passage that progressively decreases in fluid-carrying volume toward the outlet end to prevent the water from boiling away between the electrodes and further may utilize a temperatureresponsive device downstream of the electrodes to automatically adjust the spacing between the electrodes to regulate the heating.

In accordance with the present invention in a preferred embodiment shown there is provided an outer electrically non-conductive casing, a hollow, truncated cone-shaped outer electrode mounted in the casing and a truncated cone-shaped inner male electrode spaced from and concentric with the outer electrode providing an annular flow passage therebetween with the flow passage converging toward the outlet end to progressively decrease in fluid-carrying volume. A separate AV voltage is applied to at least one or both of the inner and outer electrodes, preferably about 110 volts AC on each electrode, so that with a grounded metal fluid conductive pipe being connected to the casing and at ground potential the fluid in the passage conducts the current flow from each electrode to ground thereby preventing plating or mineralization of the electrodes. The inner electrode is axially movable relative to the outer electrode and is automatically moved by a bimetallic member to adjust the spacing between the electrodes to maintain the fluid at a desired uniform temperature and a bias member automatically returns the inner electrode to a position of minimum spacing between electrodes. A flow-actuated member downstream of the electrodes and connected to a switch in the power circuit to the electrodes automatically closes the circuit when there is fluid flow through the passage. A thermostat-type switch may be used to disconnect the electric power when the temperature is excessive.

Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view of a heater unit embodying features of the present invention;

FIG. 2 is sectional view taken along lines 22 of FIG. 1;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 1;

FIG. 3A is a fragmentary sectional view taken along lines 3A-3A of FIG. 1; and

FIG. 4 is a schematic diagram showing the heating apparatus utilized in the heater unit shown in FIGS. 1-3.

Referring now to the drawings, there is shown in FIGS. l-3A an electric heater unit generally designated 10 which generally comprises a casing 11 made as an integral unit of an electrically non-conductive material, preferably a molded plastic having a hollow cylindrical body with

end portions

12 and 13 at opposite ends thereof. Internally threaded apertures 14 and 15 are formed in the

end portions

12 and 13, respectively, to define a flow inlet and flow outlets, respectively. These internally threaded end portions make the ends of the casing suitable for coupling to the male externally threaded fittings on the ends of fluid conduits or flow lines.

Within the casing 11 there is mounted an electrically conductive sleeve 18 of copper, brass or the like which surrounds and provides a support for an outer female electrode 21. The outer female electrode 21 has hollow and truncated cone-shaped inner annular surfaces which converges inwardly toward the outlet end thereof. An inner male electrode 22 is mounted within the outer electrode which is also truncated coneshaped outer annular surface which converges inwardly toward the outlet end so that the exterior surfaces of inner and outer electrodes will define an annular heating passage or chamber '23 which converges toward the outlet end so that the fluid-carrying volume of the passage progressively decreases from the inlet to the outlet and is tapered and sized to prevent the boiling away or vaporization of the conductive fluid as it is heated in and passes through the passage. The inner electrode 22 is preferably made of carbon and has a solid conductive shaft 24 extending through the center thereof. The shaft has threaded end portions 24a and 24b at opposite ends extending beyond the ends of the carbon body.

The inner electrode 22 is supported in such a way as to be guided concentrically along the longitudinal axis of the casing by means of three circumferentially spaced cylindrical or rodlike guides 25. These guides are arranged so that the upstream end portion of the inner electrode 22 slides along in a guided axial movement, as best seen in FIG. 3. The inner and outer elec trodes terminate in a spaced relation to end wall 12 to form an upstream chamber 26 in the casing 11 located upstream of the electrodes.

A disc-shaped support member 27 is provided in the casing downstream of the electrodes. Member 27 has a central aperture 27a and four circumferentially arranged and spaced apart apertures 27b. A cylindrical guide 28 is threaded on the end of the shaft 24 on the outside of a nut 29 holding the shaft 24 to the inner electrode. Guide 28 extends through the central aperture 27a and is slidable relative thereto so as to support the downstream end of the inner electrode for guided sliding movement in a coaxial relationship with the outer electrode. The circumferentially spaced apertures 27b permit the flow of the fluid therethrough. The inner and outer electrodes terminate in a spaced relation to the end wall 13 to form a downstream chamber 30 in the casing downstream of the electrodes.

An electric terminal connector for the outer electrode 21 is provided by a bolt 31 having an outer externally threaded end portion 31a and an inner externally threaded end portion 31b. The bolt 31 extends through apertures in the casing 11 and conductive sleeve 18 and threads into the outer electrode 21 to make an electrical connection with the outer electrode 21. A washer 32 and electric line 33 are secured to the outer threaded end portions 31a by a nut 34.

An electricterminal connector for the inner electrode 22 is provided by a bolt 36 having an externally threaded outer end portion 36a. Bolt extends through an aperture in the casing and an electric line 38 and washer 37 are secured to the threaded portion 360 externally of the casing by a nut 39. An inner insulated electric line 41 is connected between the bolt 36 and the threaded shaft end portion 24a. Electric line 41 is secured to shaft 24 by a nut 43 with a washer 42 between the nut and carbon body in the upstream chamber 26. An insulator cap 44 covers the connection on bolt 36 and an insulator cap 45 covers the connection to shaft 24 within the upstream chamber 26 to prevent the fluid from short-circuiting the electric connectors.

A temperature-responsive or temperature-sensitive device 46 is mounted within the casing in the downstream chamber 30 to sense the heated fluid. Device 46 is a bi-metal spring comprised of two

layers

47 and 48 that have different rates of thermal expansion. The shape of device 46 is essentially two backward S-shapes connected at the bottom and one of the downturned end portions is affixed to guide 28 and the other downturned end portion 56 is supported by a disc 50 with flow apertures 50a downstream of disc 27 and when device 46 heats, the end portions thereof move in such a way as to push the inner electrode 22 in the upstream direction against the forces of a return spring 49 in upstream chamber 26 to adjust the spacing or passage 23 between the electrodes in accordance with the fluid temperature. The return spring 49 returns the inner electrode to the position of minimum spacing between the electrodes.

A flow-actuated member 51 in the form of a circular flap is pivotally mounted in downstream chamber 30 and is responsive to the flow of fluid through the passage. The flap has a central aperture permitting it to slide over guide 28 and is mounted on a pin 52 extending through a wall of the casing. The pin 52 rotates freely permitting the member 51 to swing freely toward the downstream end when there is fluid flowing through the passage. As shown in FIG. 4, the pivot pin 52 is coupled to a pair of

rotary contact arms

54 and 55 of a rotary switch arranged in the power circuit for controlling the electric power to the electrodes. A 220 volt AC electric power source or supply represented at 56 for the system comprises a conventional three-wire source with

input lines

57 and 58 each having a separate 110 volt AC and the third ground line 58 being connected to a ground.

Active lines

57 and 58 connect to contact

arms

54 and 55, respectively, through contact arms 61 and 62, respectively, of a manual electric control switch. In turn, contact

arms

54 and 55 connect to

terminals

38 and 33, respectively, on the heater circuit. A temperature-sensitive thermostat-type switch or thermostat T1 is shown connected in line 57 and similar switch or thermostat T2 in line 58. These switches are located in the casing and open when the temperature of the heated fluid becomes excessive and automatically close when the temperature drops back below a selected maximum temperature such as l60F. The heater unit 10 is shown in FIG. 4 as being coupled between a supply conduit receiving fluid from a source and an outlet valve on faucet 66 with the supply conduit being shown as electrically grounded as is the case for most pipe systems.

In a full sequence of operation for the system shown in FIG. 4, then the contact arms 61 and 62 of the control switch are closed and valve 66 is opened to provide a fluid flow through the heater casing.

Contacts

54 and 55 close and the power circuit applies a separate AC voltage to each of the

electrodes

21 and 22. The passage 23 between the electrodes is held by a spring 49 to a minimum gap for the fastest heating switch and the passage gradually widens and increases flow as the fluid is brought up to the desired temperature. As the temperature of the fluid increases, the device 46 will press against the plunger 28 moving the inner electrode 21 in toward the upstream end and thereby widening the flow passage. In this way a substantially uniform temperature is maintained for the fluid flowing through the passage. Once the flow control valve 66 is closed the fluid flow through the passage stops, member 51 rotates to move the

contact arms

54 and 55 to an open position and open the power circuit which remains open until the control valve 66 is again opened and the heating procedure is repeated.

For some applications when only one volt line is available or that is all the power that is required then line 33 may be connected to ground and the live power line terminal is connected to line 38 as shown in FIG. 4. Conversely, this could be reversed by grounding line 38 and applying the live power line to terminal 33.

From the foregoing it is apparent that the heating apparatus above described utilizing a non-conductive casing and an electric voltage to at least one electrode will cause current flow from the electrode to ground via the water. This has been found to materially reduce electroplating or mineral build-up on the electrodes. The utilization of a heater passage which converges toward the outlet and progressively decreases in fluid-carrying volume toward the outlet in effect compresses the water and helps to avoid loss of fluid due to vaporization. The automatic adjustment of the spacing in accordance with fluid temperature affords close regulation of discharge temperature. It is also apparent that several of the heater units may be connected in series in a flow line to heat larger volumes and raise the temperatures more rapidly, if required. An optional feature would be a manual adjustment of the spacing between the inner and outer electrodes by using a threaded screw extending axially through the end of the housing and into the inner electrode 22. Further, it is apparent that the voltage to the electrodes may be adjusted to vary the temperature range of the fluid.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

What is claimed is:

1. Electric heating apparatus for heating electrically conductive fluids comprising:

an outer casing of an electrically non-conductive material having end portions defining a flow inlet and flow outlet,

a hollow, outer female electrode, disposed within said outer casing and having a truncated coneshaped inner surface,

and inner male electrode having a truncated coneshaped outer surface disposed in the outer electrode spaced from and concentric with said outer electrode surface to provide an annular flow passage therebetween having a selected gap width, said outer female and inner male electrode surfaces converging from the inlet end to the outlet end to decrease the fluid-carrying volume of said passage toward the outlet end thereby preventing the fluid from boiling away as it passes through said flow passage,

power circuit means for applying an electric voltage to at least one of said outer female and inner male electrodes using the fluid in the passage as a conductor to ground potential for the current flowof each of said electrodes to ground potential through the fluid to prevent electroplating of the electrodes,

support means at both the upstream and downstream ends of the inner male electrode for supporting said inner male electrode for axially alined movement while maintaining concentric uniformity in the annular flow passage, said support means including a plurality of circumferentially spaced guides in the upstream end of the casing engaging the periphery of the inner male electrode and a downstream support in the downstream end of the casing supporting an extension of the inner male electrode, and

axial positioning means for positioning the inner male electrode at a position of minimum spacing and axially moving the male electrode inclusive of a temperature responsive member downstream of the electrodes to automatically adjust the spacing be tween the inner and outer electrodes in response to the temperature of the fluid to maintain a substantially uniform heating effect for the fluid.

2. Electric heating apparatus as set forth in claim 1, wherein said axial positioning means includes a fluid temperature responsive bi-metallic member having an essentially double backward S-shape in the downstream end of the casing to automatically adjust the spacing between the electrodes in response to a temperature change in the fluid.

3. Electric water heating apparatus comprising:

an outer casing made of a plastic material and further including an inner metal sleeve, said casing having end portions defining a flow inlet and flow outlet at the end of the casing,

supply conduit means coupled to the flow inlet end of the casing at a ground potential,

a flow control valve coupled to the outlet end of the casing,

an outer female electrode having a truncated coneshaped inner surface mounted in said outer casing.

an inner male electrode having a truncated coneshaped inner surface spaced from and concentric within said female outer electrode to provide an annular flow passage therebetween of a selected gap width, said surfaces of the electrodes converging from the inlet end to the outlet end to decrease the fluid-carrying volume toward the outlet end thereby preventing the fluid from boiling away as it passes through said flow passage,

support means at both the upstream and downstream ends of the inner male electrode for supporting said inner male electrode for axially alined movement while maintaining concentric uniformity in the annular flow passage, said support means including a plurality of circumferentially spaced guides in the upstream end of the casing engaging the periphery of the inner male electrode and a support in the downstream, end of the casing supporting an extension of the inner male electrode,

axial positioning means for positioning the inner male electrode at a position of minimum spacing and axially moving the male electrode inclusive of a temperature responsive member downstream of the electrodes to'automatically adjust the spacing between the inner and outer electrodes in response to the temperature of the fluid to maintain a substantially uniform heating effect for the fluid, said axial positioning means for the inner male electrode including a bias spring in the upstream end of the casing urging the inner electrode to a, position of minimum spacing and a fluid temperature responsive bi-metallic spring attached at one end and having the other end affixed to the extension on the inner male electrode to automatically adjust the spacing between the electrodes in response to temperature change in the fluid,

AC power circuit means for applying a separate AC voltage to each of said inner male and outer female electrodes using the water passing through the flow passage as a conductor to the ground potential at said supply conduit means for current flow from each of said electrodes to the ground potential to prevent electroplating of the electrodes,

flow actuated means in the casing downstrea, of the electrodes coupled to the power circuit means to automatically close AC power circuit means when the flow control valve is opened and automatically open the power circuit means when the flow control valve is closed and thermostat switch means to automatacally open said AC power circuit when the temperature of the heated fluid exceeds a preselected maximum amount.

Claims

1. Electric heating apparatus for heating electrically conductive fluids comprising: an outer casing of an electrically non-conductive material having end portions defining a flow inlet and flow outlet, a hollow, outer female electrode, disposed within said outer casing and having a truncated cone-shaped inner surface, and inner male electrode having a truncated cone-shaped outer surface disposed in the outer electrode spaced from and concentric with said outer electrode surface to provide an annular flow passage therebetween having a selected gap width, said outer female and inner male electrode surfaces converging from the inlet end to the outlet end to decrease the fluidcarrying volume of said passage toward the outlet end thereby preventing the fluid from boiling away as it passes through said flow passage, power circuit means for applying an electric voltage to at least one of said outer female and inner male electrodes using the fluid in the passage as a conductor to ground potential for the current flow of each of said electrodes to ground potential through the fluid to prevent electroplating of the electrodes, support means at both the upstream and downstream ends of the inner male electrode for supporting said inner male electrode for axially alined movement while maintaining concentric uniformity in the annular flow passage, said support means including a plurality of circumferentially spaced guides in the upstream end of the casing engaging the periphery of the inner male electrode and a downstream support in the downstream end of the casing supporting an extension of the inner male electrode, and axial positioning means for positioning the inner male electrode at a position of minimum spacing and axially moving the male electrode inclusive of a temperature responsive member downstream of the electrodes to automatically adjust the spacing between the inner and outer electrodes in response to the temperature of the fluid to maintain a substantially uniform heating effect for the fluid.

3. Electric water heating apparatus comprising: an outer casing made of a plastic material and further including an inner metal sleeve, said casing having end portions defining a flow inlet and flow outlet at the end of the casing, supply conduit means coupled to the flow inlet end of the casing at a ground potential, a flow control valve coupled to the outlet end of the casing, an outer female electrode having a truncated cone-shaped inner surface mounted in said outer casing, an inner male electrode having a truncated cone-shaped inner surface spaced from and concentric within said female outer electrode to provide an annular flow passage therebetween of a selected gap width, said surfaces of the electrodes converging from the inlet end to the outlet end to decrease the fluid-cArrying volume toward the outlet end thereby preventing the fluid from boiling away as it passes through said flow passage, support means at both the upstream and downstream ends of the inner male electrode for supporting said inner male electrode for axially alined movement while maintaining concentric uniformity in the annular flow passage, said support means including a plurality of circumferentially spaced guides in the upstream end of the casing engaging the periphery of the inner male electrode and a support in the downstream, end of the casing supporting an extension of the inner male electrode, axial positioning means for positioning the inner male electrode at a position of minimum spacing and axially moving the male electrode inclusive of a temperature responsive member downstream of the electrodes to automatically adjust the spacing between the inner and outer electrodes in response to the temperature of the fluid to maintain a substantially uniform heating effect for the fluid, said axial positioning means for the inner male electrode including a bias spring in the upstream end of the casing urging the inner electrode to a position of minimum spacing and a fluid temperature responsive bi-metallic spring attached at one end and having the other end affixed to the extension on the inner male electrode to automatically adjust the spacing between the electrodes in response to temperature change in the fluid, AC power circuit means for applying a separate AC voltage to each of said inner male and outer female electrodes using the water passing through the flow passage as a conductor to the ground potential at said supply conduit means for current flow from each of said electrodes to the ground potential to prevent electroplating of the electrodes, flow actuated means in the casing downstrea, of the electrodes coupled to the power circuit means to automatically close AC power circuit means when the flow control valve is opened and automatically open the power circuit means when the flow control valve is closed and thermostat switch means to automatacally open said AC power circuit when the temperature of the heated fluid exceeds a preselected maximum amount.