US3533396A

US3533396A - Pool water heater

Info

Publication number: US3533396A
Application number: US742861A
Authority: US
Inventors: Louis M Ballard; Wayne M Beebe
Original assignee: Rusco Industries Inc
Current assignee: Rusco Industries Inc
Priority date: 1968-07-05
Filing date: 1968-07-05
Publication date: 1970-10-13
Anticipated expiration: 1987-10-13

Description

. United States Patent 1 13,533,396

I 172] Inventors Louis M.Ballard I 1,881,766 10/1932 Lundius ct a1. 431/77X Arcadia; 2,704,188 3/1955 Bergmann 237/8 Wayne M. Beebe, Pasadena, California 3,428,559 2/1969 Mclnnis 126/359X 1311 pp 742361 68 FOREIGN PATENTS 1 ggf $23 2 2 42,834 5/1888 Germany 126/355 [73] Assiunee i s by mesneassignmemsm 139,896 3/1920 Great Britain 126/359 175,430 2/1922 Great Britain 126/355 Rusco lndustnes,1nc. Los g California Great Britain... acorporafion of Delaware 582,792 11/1946 (ireat Br ta n... 126/359 1 780,675 8/1957 Great Britain 126/359 3 Primary Examiner--Frederick L. Matteson .l r. [54] POOL WATER HEATER Assisram Examiner-Robert A. Dua

Claims, 9 Drawing Figs Al!0rneyWhite and Haefliger 1 7 1 1 ABSTRACT: The disclosure concerns a pool water heater 1 1 wherein water is distributed to fall within an upright container and to be intercepted by heat transfer structure including a lower box receiving hot products of combustion, and an upper [36.] References and flue receiving the products of combustion; the flue being of UNITED STATES PATENTS folded construction and there being side outlets from the 570,128 10/1896 Haeberlin 126/355 structure to pass the hot products of combustion for heat 743,016 1 H1903 McCormick 431/77 exchange with draining water.

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a a Z W as N T L B R p; m wBB/r% M .5 R N w WW 1W POOL WATER HEATER BACKGROUND OF THE INVENTION This invention relates generally to pool water heaters, and more particularly concerns improvements in the construction and operation of such heaters.

.In the past, swimming pool water heaters have not been as efficient in their operation as desirable due to the absence of sufficient heat transfer from product of combustion to the pool water. As a result, it takes an excessively long time to raise the pool water to desired temperature, and the expense of so doing is objectionable. Among such prior heaters are those employing metallic coils in which the water circulates for receiving heat transfer through the coil wall.

SUMMARY OF THE INVENTION It is a major object of the invention to provide an improved swimming pool water heater characterized in that heat transfer to the water is extremely efficient with consequent reduced cost of heating a given volume of water through a predetermined temperature range, and with a corresponding reduced heating time. Basically, the heater comprises a container having upright walls; means to distribute pool water to fall within the container interior and to drain on the inner sides of those walls; a metallic box or shell in the lower interior of the container and having top and side walls for intercepting and draining water falling within the container interior and for transferring heat thereto from hot products of combustion within the box, the box having an upper outlet for the products of combustion, means to supply hot products of combustion to the box interior, and a flue communicating with the box upper outlet to receive the hot products of combustion, the flue having top and side walls extending generally above the box for intercepting water falling within the container interior and for transferring heat thereto from hot products of combustion within the box, the intercepted water being drained by the flue onto the box top, the lower interior of the flue being in open communication with the container interior so that hot gases may escape from within the flue to contact water draining from the flue. Typically, the flue comprises upper and lower oppositely and transversely extending sections, the upper section side walls being spaced above the lower section top wall for draining water onto the latter. Further, the upper and lower sections are typically downwardly open, whereby there is maximum contact between hot products of combustion escaping from beneath the flue sections and water draining off the section side walls, and there is highly efficient heat transfer from the hot products of combustion through the flue section top walls and to water draining onto those walls. Also, the water draining down the insides of the container walls prevents those walls from becoming heated and then radiating such heat to the exterior. Therefore, heat is progressively extracted from the hot gas that rises from the box to the flue sections, and the gas is progressively cooled, in such a way as to promote the efiicient heat transfer.

Additional objects and advantages of the invention include the provision of water distribution piping having horizontal stretches generally parallel to but spaced from the container upright walls and the box side walls, the piping stretches being above the level of the flue top wall; the provision of a burner within the container, an air blower discharging to the burner and means to supply combustible gas to the blower; the location of the burner to extend generally horizontally within the lower interior of the box, the latter being downwardly open so that hot products of combustion may escape under the box side walls for contact with draining water; and the provision of a container bottom wall spaced below the box to collect water falling or draining within the container in order to intercept heat radiation from the box interior, the container having a standpipe outlet for the collected water.

FIG. 1 is a side elevation taken in section through certain container, box and flue structure;

FIG. 2 is a vertical section taken on line 2-2 of FIG. 1;

FIG. 3 is a horizontal section taken on line 3-3 of FIG. 1;

FIG. 4 is a vertical section taken through the burner on lines 44 in FIG. I;

FIG. 5 is an enlarged vertical section taken on line 5-5 of FIG. 3;

FIG, 6 is an enlarged vertical sectiontaken on line 6-6 of FIG. 3;

FIG. 7 is an enlarged vertical section taken on lines 77 of F IG 3;

FIG. 8 is an enlarged vertical section showing blower communication with the burner piping; and

FIG. 9 is a section illustrating an igniter.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in the drawings, the pool water heater comprises a container 10 having upright side walls 11 and end walls 12, as well as a bottom wall 13. The container may be supported by structure 14 that includes upright side andend walls 15 and I6, and a bottom wall 17. A removable cover 18 containing vents 19 fits over the upper extents of the container

upright walls

11 and 12, as shown.

Means is provided to distribute pool water to fall within the container interior and drain on the inner sides of the walls II and 12. In the illustrated sample, piping horizontal stretches 20-23 extend in a loop generally parallel to but spaced from side and

end walls

11 and 12, as seen in FIG. 3, and water is supplied to the loop via upright supply pipe 24. The pipe stretches 2t]23 have

certain outlets

25, 26, and 27 sidewardly and downwardly directed, as seen in FIGS. 5-7 to spray water against the inner sides of the

walls

11 and 12.. The water thus draining down those walls forms a curtain or partition (as at 29 in FIG. 1) keeping the walls cool and absorbing heat radiated from the box structure in the interior of the container, to be described. Other outlets 30-32 from pipe sections 20-23 spray water into the container interior to drain onto such box structure for purposes to be described.

Supported within the lower interior of the container is an elongated metallic box 33 having top, side and end walls 34- 36 for intercepting and draining water falling within the container interior, and for transferring heat to such water splashing and filming on those walls. Such heat is supplied in the form of hot gaseous products of combustion which flow within the box toward an upper outlet indicated at 37. Any excess hot products of combustion may escape through the open bottom of the box, and flow upwardly (as indicated by arrows 38 in FIG. 2) through water draining off the lower edges of the box side and end walls, for heat transfer to such draining water. In this regard, the box side walls are sufficiently thin and close to the burner 60 (to be described) as to transfer heat to the draining water for producing steam rising near the box and condensing upon contact with cooler water falling openly within the container. Heating of swimming pool water above 1 10F. contributes to killing of algae growth in the water.

Further, in accordance with the invention, a flue is provided to communicate with the box outlet to receive the hot products of combustion, the flue having top, side and end walls extending generally above the box for intercepting water falling within the container interior and for transferring heat thereto from the hot products of combustion received from within the box. In the illustrated example, the flue may advantageously comprise lower and upper oppositely transversely

elongated sections

41 and 42, the former having top, side and end walls 43-45, and the latter havin top, side and end walls, 46-48, all of which may be metallicf iln this regard, and as seen in FIG. 2, water falling on top wall 46 drains down side walls 47 and onto top wall 43 spaced below those side walls; similarly water falling on top wall 43 drains down side walls 44 and onto top wall 34 of the box.

In addition, the

lower interiors

50 and 51 of the flue sections are in open communication with the container interior 52 so that hot gases may escape from within the flue to contact water draining down the

side walls

47 and 44. For this purpose, the side walls 47 are advantageously spaced above the top wall 63, and similarly, the side walls 44 are spaced above the box top wall 34, providing

side outlets

53 and 54 as seen in FIG. 2.

Arrows

55 and 56 indicated the path of hot gas escaping from those outlets. Note also that the flue sections All and 42 are downwardly open throughout their transversely elongated extents at the upper levels of side openings M and 42, to facilitate such gas escape. Upright extensions 34a and 43a on

top walls

34 and 43, respectively, help to direct the flow to the upper interiors of the flue sections, as shown. It is found that the transfer of heat from the gas becomes highly efficient with such an arrangement, due to the extensive direct contact of the hot gases with the draining pool water and to the extensive contact of the water with heated metallic surfaces. For example, water delivered to the pipe stretches 2-23 may have temperatures within the range 7()75F.; water flowing from the container via standpipe 58 for return to the pool may be heated to a temperature between 85 and 90F; and the temperature of exhaust gases leaving the container interior via vents 19 may be reduced to lie between 90 and 120? Means to supply hot products of combustion to the box interior typically includes a burner 64) within the container, an air blower 6! having an outlet 62 communicating with the burner interior, and a line to supply combustible gas to the suction side of the blower. In the illustrated embodiment, the burner 60 extends generally horizontally within the lower interior of the box 33, and it has gas-air mixture discharge ports 63 and 63a spaced along the top 64 thereof, as seen in FIG. 4. Protective flanges 65 are carried by the burner to extend over the outer ports 63, and form a flame combustion zone 66 immediately above the ports.

The generally tubular (or rectangular cross section) burner is connected with the blower outlet 52 via a riser pipe 67 extending upwardly from the bottom wall 13 of the container, flow turning vanes 68 being provided as shown. The blower is suitably mounted below the bottom wall 13 and is driven by an electric motor 69 seen in H6. 2. Both air and combustible gas are received by the blower during its operation and in proper ratio for combustion above the burner. Line 70 delivers gas to the blower, and a pressure regulator 71, solenoid controlled valve 72 and adjustable flow control valve 73 are connected in series with that line.

in operation, water is withdrawn from a pool 74 via line 75 and to a pump 76 driven by a motor 77. Water discharged by the pump passes through a filter 78 and then to the upright pipe 24 delivering to the heater apparatus. Heated water collects at 79 in the container above bottom wall 13, whereby it also receives downward radiation of heat from the burner and through the open bottom of the box 33. Water collecting above the level of the standpipe 58 drains therethrough, for gravity return to the pool at 80.

A source 231 of electrical power is connected with the pump motor 77 and blower motor 69 via switch 82 and leads 83 and 8d; accordingly when water is circulating through the heater, the blower is operating, the switch 82 being closed. Also, power is delivered via lead 85 to a control circuit 86 outside the container and having control connection at 67 to the solenoid actuated valve 72 and having connection at 88 to a glow element 89. The latter is at one end of the burner, close enough to the combustible mixture to ignite same, but not to extend in the flame path, so as not to be destroyed. In this regard, the temperature in the flame zone is in excess of 1,500F. Thus under control of the circuitry 36, power is supplied to open or close valve 72 and to heat (or stop heating of) the glow element 89.

An input water temperature sensor, as for example a thermostat 90, is connected into pipe 24 and has connection via lead 91 with circuit 86. If the water temperature drops below a predetermined lower limit, the circuit 86 is operated first to effect power energization of the glow element 89, and soon thereafter to open the solenoid controlled valve 72 so that gas is delivered to the operating blower 61. The gas-air mixture is then ignited by element 89. If the water temperature in pipe 24 rises to an upper limit, the solenoid valve 7'2 is closed.

Also provided is a flame sensor operable to control the circuit 86 to effect closing of the valve 72 in response to a predetermined reduction in flame production from the burner. For example, a thermistor element may be mounted in the box 33 in proximity to the flames 1M, and have circuit connection at 102 with the control circuit as. This assures that when flame production ceases, for any reason, the gas supply will be shut down.

Referring now to FIG. 9, the igniter element 89a there shown is especially well adapted to use in the present apparatus. That element includes a glow wire 1 it), which may for example consist of platinum or iridium, to which electrical current is supplied via a central conductor ltll of cable 88a. The wire is suspended between stainless steel electrode 113 mounted on a projecting portion of conductor III and electrode 114 mounted on cable sheath 115. A tetrafluoroethylene insulator 116 covers the conductor H1 and is in turn covered by the sheath to protect the insulator from the extremely high temperatures in the region adjacent the burner 60.

The sheath may advantageously consist of a metal such as copper capable of transferring heat rapidly along the sheath to a point remote from the high temperature burner region. As shown in FIG. 1, the cable 88a extends downwardly into the pool 79 of water, to which heat is rapidly transferred in order to maintain the integrity of the insulative covering 116. From the pool, the cable runs down through an access standpipe 117 to the control 86. That standpipe may also pass the cable 02 by which the thermistor 100 is connected to control 86.

We claim:

1. A pool water heater, comprising:

a container having upright walls;

means to distribute pool water to fall within the container interior and to drain on the inner sides of said walls;

a box in the lower interior of the container and having top and side walls for intercepting and draining water falling within the container interior and for transferring heat thereto from hot products of combustion within the box, the box having an outlet for said products of combustion;

means to supply hot products of combustion to the box interior; and

a flue comprising generally horizontally endwise elongated upper and lower sections communicating with said box outlet and with each other to receive said hot products of combustion for sequential endwise flow through the sections the flue sections having elongated top and side walls extending generally above the box for intercepting water falling within the container interior and for transferring heat thereto from hot products of combustion received from within the box, the intercepted water being drained by the flue onto the box top, the lower interior of the flue being in open communication with the container interior so that hot gases may escape from within the flue to contact water draining therefrom, the flue section side walls forming outlet openings spaced below the levels of the upper interiors of the respective sections to facilitate escape of portions of said hot products of combustion from within the flue sections and into contact with the draining water.

2. The heater of claim 1 wherein the flue upper section side walls are spaced above the flue lower section top wall for draining water onto said lower section top wall.

3. The heater of claim 1 wherein both of said sections are downwardly open at the uppermost levels of said side openings.

4. The heater of claim 1 wherein said water distribution means comprises piping having horizontal stretches generally parallel to but spaced from the container upright walls and the box side walls, the piping stretches being above the level of said flue top wall.

5. The heater of claim 1 wherein said means to supply hot products of combustion to the box interior includes a burner within the container, an air blower having an outlet communicating with the burner interior, and means to supply combustible gas to said blower.

6. The heater of claim 5 wherein said burner extends generally horizontally within the lower interior of said box, and said box is downwardly open so that hot products of combustion may escape under said box side walls for contact with water draining therefrom.

7. The heater of claim 6 in which the container has a bottom wall spaced below said box to collect water falling within the container interior in order to intercept downward radiation of heat from the box interior, the container having an outlet for said collected water at a level such that a predetermined level of said water is maintained over said container bottom wall.

8. The heater of claim 5 wherein said means to supply combustible gas to the blower includes a valve, and a circuit to control operation of said valve in response to changes in temperature of pool water being supplied to fall within the container interior.

9. The heater of claim 8 including a flame sensor operable to control said circuit to effect closing of said valve in response to a predetermined reduction in flame production from said burner.

10. The heater of claim 8 wherein said circuit is outside said container and said sensor is proximate the burner, within the container, a cable extending from the interior to the exterior of the container for electrically interconnecting said circuit and sensor, the container having a bottom to collect water falling within the container interior to stand in a pool, and a standpipe projecting upwardly in said pool from said bottom and through which said cable extends.

11. The heater of claim 5 including an electrically energizable device within the container to ignite said combustible gas, a cable leading from said device to the container exterior, the container having a bottom above which water falling within the container collects in a pool, said cable extending in said pool and being capable of transferring heat by conduction there along from a region proximate said device to said pool.

12. The heater of claim 11 in which said device comprises a glow wire, the cable includes an electrical conductor, an insulative covering about the conductor and a heat transferring metallic sheath about said covering, and including a pipe projecting upwardly within the pool and through which said cable extends from below the container to a point within the container and above the pool.

13. The heater of claim 6 wherein said box side walls are sufficiently thin and close to the burner as to transfer heat to the water draining thereon for producing steam which is condensed upon contact with cooler water falling openly within the container. t

14. In a swimming pool water heater, a container, means to distribute pool water to fall within thecontainer, a burner within the container, and box and flue structure extending over the burner to intercept and drain the falling water, the box and flue structure vented to pass hot products of cornbustion into the draining water, the flue structure being folded to direct the flow of said hot products of combustion transversely back and forth at different levels accompanied by progressive escape of said products of combustion via said venting arid means supplying combustible gas to the burner at a rate such that the heat generated upon combustion is sufficient when transferred to the water via the box structure as to produce steam which is condensed upon contact with water falling within the container.