Pool water temperature control

[57] ABSTRACT

A dual temperature control system to regulate separately the water temperature in a swimming pool and in an adjacent therapeutic pool with the use of a single heater and circulating pump. Valve means in one position direct substantially all circulating water to the swimming pool at low back pressure and in a second position direct substantially all water flow to the therapeutic pool at a higher back pressure. A spa temperature control which is responsive to the higher back pressure or is electrically actuated in concurrence with the valve means, overrides the main heater thermostatic control and regulates the temperature of water flowing to the therapeutic pool at a level higher than that normally supplied to the swimming pool.

Claims, 11 Drawing Figures

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PATENTED JAN 11974

3,781.925

SHEET 1 OF 3

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FIG —1

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PATENTEOJAS IM 3.781.925

SHEET 2 OF 3

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PATENTED JAN 11974

3,781,925

SHEET 3 OF 3

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3,781,925

POOL WATER TEMPERATURE CONTROL

This invention relates generally to heated water circulating systems for swimming pools and more particularly to a system for controlling separately the water temperature in a swimming and therapeutic pool, in 5 combination or as a detached spa.

Therapeutic pool water usually is heated to a level of about 105° whereas swimming pool water normally is regulated at 80° F. or less. Since it is unduly expensive for most users to heat an entire swimming pool to the 10 higher temperature suitable for therapeutic use, a separate “spa” or therapeutic pool is usually constructed at the shallow end of the swimming pool. This invention is a control system which enables a common heater and pump to circulate both pools separately at the different 15 service temperature levels required.

A primary object of the invention is a dual temperature control system which enables use of a single heater and pump to circulate heated water separately to a swimming pool and to a therapeutic pool at different 20 predetermined temperature levels.

Another object of the invention is a dual temperature control system which automatically regulates the water temperature at the appropriate level in response to a switch of circulating water flow from swimming to ther- 25 apeutic pool or vice versa.

Other objects and advantages of the invention will become apparent upon consideration of the following description and the accompanying drawings wherein

FIG. 1 is a schematic flow diagram of the system with ³⁰the valve means in its first position;

FIG. 2 is a schematic flow diagram of the system with the valve means in its second position;

FIG. 3 is a perspective view of an improved valve means useful in one embodiment of the invention; ³⁵

FIG. 4 is a top view of the valve means of FIG. 3;

FIG. 5 is an exploded view in perspective of the interior components of the valve means of FIG. 3;

FIG. 6 is a perspective view of the spa temperature control of the system; ⁴⁰

FIG. 7 is a side view partly in section of the spa temperature control of FIG. 6;

FIG. 8 is an end view partly in section showing the spa temperature control of FIG. 6;

FIG. 9 is a sectional view of the spa temperature con- ⁴⁵trol taken at line 9—9 of FIG. 7;

FIG. 10 is a schematic diagram of the electrical circuit of one embodiment of this invention; and

FIG. 11 is a schematic diagram of the electrical circuit of another embodiment of this invention. ⁵⁰

The pool system illustrated schematically in FIGS. 1, 2 has circulating heated water flow as indicated by arrows 10 which show the direction of water flow. Swimming pool 11 and therapeutic pool or spa 12 have a common heater 13, a common circulating pump 14 and a main thermostatic temperature cbntrol IS for regulating normal water temperature in swimming pool 11 at a comfortable swimming level. Dual valve means 16 shown in its first position in FIG. 1 directs substantially ₆θ all circulating water to swimming pool 11 and returns ° water from that pool to the pump suction and heater for recirculation. Valve means 16 is essentially a pair of concurrently actuated three-way valves, one for the pool return lines and one for the suction lines. In this ₆₅first position of valve means 16, main thermostatic control 15 regulates the circulating water to a temperature suitable for use in swimming pool 11 usually ranging up to about 80° F. In this first position of the valve means spa control 17 is inactive.

In its second position shown in FIG. 2, dual valve means 16 directs substantially all circulating water flow to the spa 12. In that condition spa temperature control 17 overrides the main control 15 and regulates the circulating water to a temperature suitable for use in therapeutic pool 12 at a higher temperature level in the order of 105° F, the maximum temperature for most pool heaters.

The swimming pool 11 and spa 12 shown in FIGS. 1 and 2 generally are contained in the same general structure 18. An interior wall 19, for example, extends from the pool water surface to the bottom of the structure to separate the water in spa 12 from that in swimming pool 11.

For swimming service centrifugal pump 14 normally circulates heated water through the main and spa temperature controls 15, 17 and heater 13 through heater discharge line 20 to one portion of valve means 16. That portion directs substantially all water flow through swimming pool return line 22 and branch return lines 23, 24 to the swimming pool. All of these lines have a relatively large flow capacity so that the system operates at a normal low back pressure level on the centrifugal pump characteristic curve to assure a large volume of water flow. The swimming pool water in the first position of valve means 16 returns through suction lines from a surface skimmer and main outlet 28, 29, for example, through common suction line 27, a second portion of valve means 16 and pump suction line 25 to the circulating pump 14. All of these lines are designed for a low head high volume operation on the pump characteristic curve.

On the other hand, in the second position for valve means 16 shown in FIG. 2 for spa or therapeutic pool circulation, pump 14 circulates the water through the main and spa controls 15, 17 and heater 13 through heater discharge line 20 to the first portion of valve means 16. In this second position the valve directs flow through return line 21 to the spa 12. Spa return line 21 is sized for lower capacity than the pool return lines 22, 23, 24 or is provided with a nozzle 30 at its end for high inlet velocity and may have a special fitting for introducing air into the water stream. The restrictive spa return line 21 and/or the nozzle 30 or fitting at the inlet to the spa moves the system operating point to a higher pressure level on the pump characteristic curve. In this condition the back pressure of the system at the spa control 17 is substantially higher than that in the first valve position for swimming use. A system back pressure differential in the order of 1 pound per square inch has been found to be satisfactory for the embodiment of the spa control illustrated in FIGS. 6 - 10. In the second position of valve means 16 the circulating water flows from the spa through spa suction line 26, the second portion of valve means 16, and pump suction line 25 to pump 14 as indicated by arrows 10.

Valve means 16 cooperates with the main and spa temperature controls 15, 17 respectively, so that when valve means 16 manually or otherwise is in the first position shown in FIG. 1, the main thermostatic control 15 assumes regulation of water temperature for the swimming pool. When valve means 16 switches to its second position shown in FIG. 2, spa temperature control 17 regulates circulating water temperature to a higher level for use in the spa.

3,781,925

FIGS. 6-10 illustrate one embodiment of spa control 17 which assumes temperature control by virtue of the increase in back pressure at the control when the valve means 16 switches to circulate the spa 12. The control becomes inactive when the valve means switches to the first position to circulate swimming pool 11 at lower back pressure. FIG. 11 illustrates another embodiment of the system wherein valve means 16 are a pair of three-way electrically operated solenoid valves energized simultaneously with a relay that actuates the spa control 17. In this embodiment switchover from one control to the other is independent of the system back pressure at spa control 17.

FIGS. 3-5 show one embodiment of dual valve means 16 useful in the system. It is substantially a pair of simultaneously manually operated three-way valves. The valve means direct substantially all water flow to and withdraw it from the swimming pool 11 in a first position with little or no flow to the spa 12. In a second position the valve means 16 direct substantially all water flow to and withdraw it from spa 12 with little or no flow to the swimming pool 11. The valve structure comprises a hollow cylindrical shell 31 provided with a plurality of ports, namely a first inlet port 32 at one end; a first outlet port 37 at the other end; a pair of coaxial second outlet ports 33, 34 disposed 180° apart in the vicinity of port 32; and a pair of coaxial second inlet ports 35, 36 disposed 180° apart in the vicinity of port 37.

An inner rotatable sleeve 38 shown in FIG. 5 fits snugly within shell 31. The outside diameter of the sleeve 38 is slightly less than that of the inside diameter of shell 31. A solid transverse interior barrier 39 divides the hollow interior of sleeve 38 into two portions. The upper inlet portion of the sleeve has a first sleeve port 40 and the lower outlet portion has a second sleeve port 41. Sleeve 38 is rotatable about its axis within the shell so that port 40 can be moved to coincide with one or the other of second outlet ports 33, 34. At the same time second sleeve port 41 will coincide with one or the other of second inlet ports 35, 36 in the shell. A handle 42 mounted at one end of depending shaft 43 is pinned to the sleeve for rotation of it by means of pin 44 which passes through a pair of holes 45 in the sleeve walls. The sleeve and handle assembly shown in FIG. 5 mounts within the shell 31. Cap 46 through which shaft 43 passes in a water tight seal secures that assembly to the shell and closes off the upper end of the shell. The lower open end of the shell is the outlet port 37 which coincides with the open outlet end 47 of inner sleeve 38. The upper open inlet end 48 of the sleeve communicates with the first inlet port 32 in the valve shell.

When the valve means is in its first position shown generally in FIG. 1 water flows into first inlet port 32 from heater discharge line 20 and the heater, through the open inlet end 48 in inner sleeve 38, then out of the sleeve through first sleeve port 40 and finally out of outlet pbrt 33 in the shell to swimming pool return line 22. The inner sleeve 38 in that first position closes off outlet port 34 in the shell.

At the same time inlet port 35 in the shell, which is piped to swimming pool suction line 27, communicates through second sleeve port 41 the interior of sleeve 38 and its open outlet end 47 with first outlet port 37 and pump suction line 25 which is piped to it. In that first position the inner sleeve 38 closes off outlet port 36 in the shell.

In the second position of valve means shown in FIG. 2 handle 42 is rotated 180 degrees from its first position. There the water flow from heater discharge line 20 passes through first inlet port 32, the inlet end 48 of the sleeve and its interior, and then through first sleeve port 40 which now coincides with second outlet port 34 that is piped to spa return line 21. In this second position the sleeve 38 closes off outlet port 33 to the swimming pool. At the same time second inlet port 36 which is piped from the spa suction line 26 communicates through second sleeve port 41 in the inner sleeve to first outlet port 37 and the pump suction line 25. The sleeve closes inlet port 35.

In this manner the valve means in a first position direct substantially all circulating water to the swimming pool and withdraw it from that pool to the circulating pump. In the second position by simple manipulation of valve handle 42 the valve means direct substantially all water flow through the spa. It usually is desirable to maintain a small flow through the spa or swimming pool when the other of the two pools is being circulated so that dirt is continually washed from the pool to the filter and oxidizing agents are continually supplied for algae control. This is accomplished in the disclosed system by providing small diameter bypass pipes 21' and 26' around valve means 16.

FIG. 6 is a perspective view of one spa temperature control 17 useful in the described system. It easily can be inserted into a new or existing circulating system by means of flexible couplings 50 that connect into the heater inlet line. The control of FIG. 6 as is more clearly shown in FIGS. 7-9 comprises a section of pipe 51 within which is formed a well 52 that carries a bimetallic millivolt thermostat 53 commonly used in swimming pool service. The temperature regulation of thermostat 53 is adjustable by means of potentiometer 54. A pressure sensing pitot tube 55 also mounts within the pipe section 51 adjacent to well 52 which carries the thermostat 53. Its open end faces the direction of water flow as shown in FIG. 7 and communicates the water pressure through the illustrated conduit 56 to pressure switch 57. Protective housing 58 encloses the assembly.

FIG. 7 illustrates the electrical relationship between the main thermostatic control 15 and spa control 17. The main control 15 shown is typical of the millivolt units usually supplied to regulate the water temperature of a swimming pool. It is a millivolt system for controlling the gas supply to the burner in the heater 13. A solenoid operated control valve 60 in the gas supply line is operated by a millivolt system including in series a thermostat 61, a high temperature limit switch 62, and a pressure switch 63 that senses the water pressure in the inlet to heater 13. Thermostat 61 in the main thermostatic control 15 normally senses the water temperature of the circulating pool water at the heater inlet. If the water temperature is lower than the point to which the temperature is to be regulated, thermostat 61 closes the millivolt circuit and opens the gas valve to start the burner from its pilot light and to heat the circulating water until it reaches the temperature of the set point. At that temperature thermostat 61 opens the circuit and the gas supply to the burner shuts off. Pressure switch 63 is set to sense a low water pressure in the heater inlet line and to disable the main thermostatic control if that pressure is low, for example, because there is no flow from the circulating pump. High temperature limit switch 62 opens the millivolt operating

3,781,925 circuit if the pool temperature becomes too high, for example, by a blocked line from the pool heater.

Under normal swimming conditions the main thermostatic control 15 regulates the swimming pool water temperature to the set point on thermostat 61. In the 5 described embodiment the thermostat 53 and pressure switch 57 of the spa temperature control 17 are connected in parallel around thermostat 61. Pressure switch 57 senses the water pressure in the inlet line to the heater. While the swimming pool is being circulated 10 at relatively low back pressure that switch is open and the spa temperature control 17 is inactive. However, when the valve means 16 switches water flow to the spa, the higher back pressure developed at the spa temperature control closes pressure switch 57. Then ther- 15 mostat 53 set at the higher spa water temperature overrides the main thermostatic control 15, energizes the millivolt circuit to gas valve 60, and regulates the circulating water to the selected spa temperature level.

It should be understood that the same spa control 20 combination of thermostat 53 and pressure switch 57 can be mounted directly on the pool heater rather then in the assembly illustrated in FIGS. 6-9. The pressure switch 57 sensor, for example, can be connected to the same point at the heater inlet as is the sensor for pres- 25 sure switch 62 in the main control IS. Thermostat 53 can be the immersion type also connected to the heater inlet header.

FIG. 10 illustrates an alternative all electrical system including gas control valve 60 with a millivolt operating 30 circuit for its solenoid comprising thermostat 61, high limit switch 62 and pressure switch 63. In this embodiment thermostat 53 of the spa control is in series with 24 volt relay 65 and both are connected in parallel with thermostat 61. A remote operating switch 66 in 24 volt 35 operating volt circuit supplied from the line through transformer 67 simultaneously closes relay 65 to actuate the spa temperature control 17 and operates a pair of three-way solenoid valves 68, 69 which are the valve means 16 in this embodiment. In combination they 40 switch the water flow through the spa in a manner similar to the second position illustrated for the valve structure in FIGS. 3-5. When remote operating switch 66 is open relay 65 opens and spa temperature control 17 is inactive and three-way valves 68, 69 assume a first 45 position to circulate the swimming pool. Thus, in the arrangement of FIG. 10 relay 65 simultaneously with operation of the valve means switches the system from spa to swimming pool operation and vice versa electrically without dependence upon back pressure at the 50 spa control as is the case with the embodiment illustrated in FIGS. 6 - 10.

The several embodiments of the invention are for illustrative purposes only. It will be apparent to those familiar with this art that other variations or modifica- 55 tions can be made within the scope of the invention defined in the following claims.