Method and device for controlling jet flow intensity for a spa

[0001] The present invention relates to spas, and in particular, to water pumps for spas.

[0002] A spa (also commonly known as a hot tub) is a therapeutic bath in which all or part of a person's body is exposed to hot water, usually with forceful whirling currents. When located indoors and equipped with fill and drain features like a bathtub, the spa is typically referred to as a whirlpool bath. Typically, the spa's hot water is generated when water contacts a heating element in a water circulating heating pipe system.

[0003] FIG. 1 shows a prior art hot tub spa 1. Spa controller 52 is programmed to control the spa's components, such as the spa's water pumps 1P and 2P, air blower 3, ozonator 7, stereo 1A, and light 1L. In normal operation, water from drains 13A and 13B is pumped by water pump 2P back into tub 2 and by pump 1P through heater 5A where it is heated by heating element 5B. The heated water then leaves heater 5A and enters spa tub 2 through jets 11. Water leaves spa tub 2 through drains 13A and 13B and the cycle is repeated.

[0004] The therapeutic effect provided by the variation of the intensity of the water stream leaving jets 11 is a desirable feature for a spa. In the prior art, variation of the intensity of the water stream is achieved by utilization of a variety of different prior art methods. For example, the orifice of the jet itself can be adjustable so that flow of water can be restricted thereby decreasing its flow intensity. Also, diverter valves can be used to spread the flow from the water pump over a greater or lesser number of jets to change the flow, and consequently the intensity, through a particular jet or group of jets. Or a variable speed water pump can be utilized to control the intensity of the flow. For example, as the pump is slowed down, the intensity of flow through a jet will decrease. Likewise, as the speed of the pump is increased, the intensity of the flow through a jet will increase.

[0005] The variable speed pump depends on the use of a universal variable speed motor to vary the speed of the pump. An increase of amperage to the motor increases the RPM of the motor. Likewise, decreasing the amperage decreases the motor's RPM. Adjusting the RPM of the motor naturally adjusts the flow rate of the pump and the intensity of the water leaving the jets.

[0006] There are several disadvantages associated with the utilization of a prior art variable speed pump for a spa. Some of these disadvantages are: 1) pump size, 2) excessive noise, and 3) high cost.

[0007] Available variable speed pumps tend to be built to include a universal motor designed for the vacuum cleaner industry. Therefore, the choices of motor size and power are limited to what is available for the larger, more popular, vacuum cleaner market. This means, typically, that the current variable speed pumps are only commonly used for indoor whirlpool bath applications and not in the larger outdoor portable spas. It is more desirable to have a larger pump for an outdoor portable spa because the outdoor portable spa usually contains a larger volume of water than a whirlpool bath.

[0008] Another disadvantage associated with prior art variable speed pumps for spas is that the universal variable speed motor is very loud.

[0009] Variable speed pumps are expensive. For example a typical variable speed pump for an indoor whirlpool bath can cost approximately $120.00. In contrast a similarly sized pump having a single speed induction motor and can cost approximately $50.00 (less than half the price of the variable speed pump).

[0010] Cavitation is a well known phenomena associated with fluid pumps. Cavitation can occur in a hydraulic system as a result of low fluid levels that draw air into the system, producing tiny bubbles that expand explosively at the pump outlet, causing reduction in pump delivery capacity, metal erosion and eventual pump destruction.

[0011] Air drawn into the pump system through cavitation is potentially very harmful to a pump and is generally to be avoided. However, it is known that air can purposely be added to a fluid pump suction in a manner that will not cause damage to the pump. It is known to add air to the suction of a single speed pump to vary the delivery capacity of the pump.

[0012] FIG. 5 shows a prior art spa whirlpool bath 130 having manually controlled air valve 120. GG Industries with offices in Valencia, Calif. currently manufactures manually controlled air valves (part nos. 99126 and 99128) similar to air valve 120 for utilization in spas.

[0013] Air valve 120 has an orifice. The amount of air that is allowed to enter the orifice is controlled by the turning of knob 121. For example, when knob 121 is fully turned in the clockwise direction, the orifice is completely covered and no air enters air line 122. However, as knob 121 is turned counterclockwise, the orifice is gradually revealed. When knob 121 is turned fully counterclockwise, the orifice is completely uncovered and the maximum amount of air is allowed into air line 122.

[0014] The delivery capacity of single speed induction motor pump 124 varies as air is added to the suction of pump 124 via air line 122. The greater the amount of air added, the lower the delivery capacity of pump 124. By varying the delivery capacity of pump 124, the user varies the intensity of the flow leaving jets 123.

[0015] What is needed is a better way to control the intensity of flow of water entering the spa tub via the spa jets.

[0016] The present invention provides a method and device for controlling the intensity of flow of water leaving a single speed water pump and entering a spa tub. A single speed water pump is connected to a spa tub via a pump suction pipe and a pump outlet pipe. The single speed water pump has its suction connected to the spa tub and sucks water out of the spa tub via the pump suction pipe. A controller is electrically connected to at least one air valve and the air valve is connected to the pump suction pipe. The controller opens the air valve to allow air into the pump suction. Air from the air valve mixes with water pumped from the tub to create an air/water mixture. The air water mixture is pumped back into the spa tub via the pump outlet pipe. The intensity of the flow of the air water mixture back into the spa tub depends upon the amount of air allowed into the air/water mixture via the air valve. Preferably, the controller is programmed with programming instructions to vary the intensity of the flow of the air/water mixture back into the spa tub. Also, several air valves may be utilized to provide a range of air flows.

[0017] FIG. 1 shows a prior art spa.

[0018] FIG. 2 shows a side view of a preferred embodiment of the present invention.

[0019] FIG. 3 shows a top view of a preferred embodiment of the present invention.

[0020] FIG. 4 shows another preferred embodiment of the present invention.

[0021] FIG. 5 shows a prior art whirlpool bath.

[0022] A detailed description of a preferred embodiment of the present invention may be described by reference to FIGS. 2-4. In the present invention, the intensity of the flow leaving jets 71 (FIGS. 2 and 3) is controlled by controller 75. Controller 75 can be pre-programmed at the factory, it can be programmed directly by the user utilizing keypad 74 or the intensity of the flow leaving jets 71 can be controlled by the user in a direct fashion via controller 75 by the manipulation of keypad 74.

[0023] FIG. 2 shows a side view and FIG. 3 shows a top view of the first preferred embodiment of the present invention. Spa 61 is a whirlpool bath. Prior to entering spa 61, the user fills tub 62 by turning hand valve 63. Water (set to a temperature preferred by the user) then exits faucet 64 and enters tub 62. When the user is finished relaxing in spa 61, he may remove stopper 65 and water will be drained out through drainpipe 66.

[0024] While spa 61 is in operation, pump 69 pumps the water in tub 62 into pipe 68. Pump 69 sucks the water from pipe 68 into pipe 70 and then forces it out through jets 71 back into tub 62. Preferably, pump 69 is a single speed induction motor pump.

[0025] Because pump 69 is a single speed induction motor pump, the speed of the pump's motor is constant and is not varied. However, the intensity and flow rate of the water (in gallons per minute) flowing through pipe 70 and out through jets 71 can be varied by introducing air into pump suction pipe 68. The introduction of air into the suction of pump 69 causes pump 69 to operate less efficiently. Therefore, when air is introduced into pipe 68, water leaving pump 69 does so at a lower speed and with reduced intensity.

[0026] Normally, as stated in the Background of the Invention section, air added to a pump through cavitation can cause damage to a pump. However, when done in a controlled fashion, the harmful effects adding air to a pump can be greatly diminished and even eliminated.

[0027] Keypad 74 is electrically connected to controller 75. Controller 75 is also electrically connected to air valves 72 and 73. A user sitting in spa 61 can manipulate keypad 74. For example, after pressing keys on keypad 74, controller 75 will send corresponding electrical signals to either open or shut air valves 72 and 73. Preferably, air valves 72 and 73 are solenoid air valves manufactured by Evolutionary Concepts, Inc. with offices in San Dimas, Calif. Air valve 72 is preferably part no. 620-220 and has a 0.047 inch orifice and air valve 73 is preferably part no. 621-220 and has a 0.062 inch orifice. Through experimentation, Applicant has concluded that orifices of 0.047 inch and 0.062 inch are preferred and result in no noticeable damage to the pump.

[0028] Water flowing through pipe 68 creates a drop in pressure through pipe 68. Hence, after the opening of air valves 72 and/or 73, the moving water draws air into pipe 68 through pipe 76 via the venturi effect (as the speed of a moving fluid (liquid or gas) increases, the pressure within that fluid decreases).

[0029] A mixture of air and water enters pump 69. The greater the amount of air that is present in the air/water mixture, the less efficient the operation of pump 69. For example, when both air valves 72 and 73 (FIG. 3) are closed, pump 69 operates at maximum efficiency and the speed of the water leaving jets 71 is at its highest. Likewise when both valves 72 and 73 are open, pump 69 is operating at its lowest efficiency and speed of the water leaving jets 71 is at its lowest. Table 1 summarizes the relationship of the speed of the water leaving the jets and the position of solenoid air valves 72 and 73.

TABLE 1
	Position of Valve 72	Position of Valve 73
Speed of Water Leaving Jets	(orifice .047 inch)	(orifice .062 inch)
High Speed	Closed	Closed
Med-High Speed	Open	Closed
Med-Low Speed	Closed	Open
Low Speed	Open	Open

[0030] In the second preferred embodiment, controller 75 has been pre-programmed at the factory so that the flow of the water leaving jets 71 creates a soothing wave effect. For example, controller 75 is programmed to automatically open and shut valves 72 and 73 so that the speed of the water exiting jets 71 varies from High Speed to Med-High Speed to Med-Low Speed to Low Speed in a repetitive manner until the user turns pump 69 off. Table 2 summarizes a preferred sequence in which every 12 seconds the cycle is repeated until the user turns pump 69 off.

TABLE 2
Speed
of Water	Position of Valve 72	Position of Valve 73	Time
Leaving Jets	(orifice .047 inch)	(orifice .062 inch)	(secs)
High Speed	Closed	Closed	T 0-3 secs
Med-High	Open	Closed	T 3-6 secs
Speed
Med-Low	Closed	Open	T 6-9 secs
Speed
Low Speed	Open	Open	T 9-12 secs*
*from t 12 secs until finish, repeat sequence.

[0031] The third preferred embodiment is similar to the second preferred embodiment, except that a user can personally program controller 75 to switch between the speed settings in a fashion according to the specific preferences of the user. For example, in one preferred embodiment the user may program controller 75 so that water leaving jets is at a High Speed for 1 minute, to be followed immediately by Low Speed for 10 seconds, then Med-Low Speed for 10 seconds, and then Med-High Speed for 10 seconds. The user may also program this cycle to repeat for a specific amount of time, or alternatively he can have it repeat indefinitely until he turns pump 69 off.

[0032] FIG. 4 shows a fourth preferred embodiment of the present invention in which the present invention is utilized with a portable spa. Spa 81 is a portable spa similar to the portable spa shown in FIG. 1 and described above in the Background section, with the exception that spa 81 utilizes the introduction of air into pipes 93 and 94 to control the speed and intensity of water leaving pumps 91 and 92, respectively. Air valves 72A and 73A and air valves 72B and 73B are controlled by spa controller 52. Preferably a user sitting in tub 2 manipulates keypad 8 to control valves 72A, 73A, 72B, and 73B in a fashion similar to that described above in reference to the other preferred embodiments. Air entering valves 72A and 73A is drawn into pipe 93 via the venturi effect, causing the speed and intensity of water leaving pump 91 to diminish. Likewise, air entering valves 72B and 73B is drawn into pipe 94 via the venturi effect, causing the speed and intensity of water leaving pump 92 to diminish. As with the second preferred embodiment, the user can control which air valves to open or shut by pressing keypad 8. Or, as was the case with the second and third preferred embodiments, spa controller 52 can be programmed to open or shut the air valves is a cyclic sequence.

[0033] Although the above-preferred embodiments have been described with specificity, persons skilled in this art will recognize that many changes to the specific embodiments disclosed above could be made without departing from the spirit of the invention. For example, although it was stated that through experimentation Applicant has concluded that orifices of 0.047 inch and 0.062 inch are preferred, other orifice sizes could be utilized as well. Also, although the preferred embodiments disclosed two air valves 72 and 73, it would also be possible to utilize just one air valve or more than two air valves (for example, three or four air valves). Also, although the above preferred embodiments disclosed air valves that could be either fully open or fully closed, it is possible to utilize an air valve that can gradually be opened or closed. This air valve would be more expensive, but would give more precise control to the amount of air allowed into the pump suction. Therefore, the attached claims and their legal equivalents should determine the scope of the invention.