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Title:
METHODS AND APPARATUS FOR CONTROL OF SWIMMING POOL WATER LEVEL
Document Type and Number:
WIPO Patent Application WO/2001/002675
Kind Code:
A1
Abstract:
Methods and devices for detecting the level of water (12) in a swimming pool (10) and controlling that level. A water level sensor (50), preferably disposed beneath the skimmer cap (52) for a pool (10), has a magnetic or electronic float assembly (56, 58) and a transmitter (64) for providing a signal, such as a radio frequency or infrared signal (74). A flow controller having a receiver unit (72) and a valve assembly (78) is associated with a water inflow line (20) that replenishes the pool water (12). A low water condition in the pool (10), triggers the float switch (56) to cause the transmitter (64) to generate a signal (74) indicative of a low water condition. The receiver unit (72) receives the signal (74) generated by the transmitter (64) and, in response thereto, selectively actuates the valve assembly (78).

Inventors:
TRAYNOR TERRY
Application Number:
PCT/US2000/018473
Publication Date:
January 11, 2001
Filing Date:
July 06, 2000
Export Citation:
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Assignee:
POOL BUTLER INC (US)
International Classes:
E04H4/12; (IPC1-7): E04H4/14
Foreign References:
US5804080A1998-09-08
US4445238A1984-05-01
US3895402A1975-07-22
US3837015A1974-09-24
US2809752A1957-10-15
Attorney, Agent or Firm:
Bradley, James E. (L.L.P. P.O. Box 6138, Houston TX, US)
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Claims:
CLAIMS
1. A device for the control of water level in a swimming pool, comprising: a) a water level sensor for detecting water level within a pool and generating a signal upon detection of a low water level ; b) a receiver unit for receiving the signal generated by the water level sensor and selectively operating a valve in response thereto to replenish water within the pool.
2. The water level control device of claim 1 wherein the water level sensor comprises a float assembly for detecting a low water condition in a pool, having a float member whose position is sensitive to water level within a pool.
3. The water level control device of claim 2 wherein the water level sensor further comprises a transmitter for generating a radio frequency signal upon detection of a low water level.
4. The water level control device of claim 3 wherein the signal is coded to a particular frequency to help preclude interference by other signals.
5. The water level control device of claim 1 wherein the receiver unit provides a predetermined fill period.
6. The water level control device of claim 5 wherein the predetermined fill period is approximately 10 minutes.
7. The water level control device of claim 1 wherein the receiver unit provides a maximum cumulative fill time.
8. The water level control device of claim 7 wherein the maximum cumulative fill time is approximately three hours.
9. The water level control device of claim 1 wherein the receiver unit further comprises a programmable microprocessor for selectively controlling a valve.
10. A device for the control of water level in a body of liquid such as a swimming pool, comprising: a) a sensor for detecting a low water condition in a swimming pool; b) a controller for selectively operating a valve for replenishing water within the swimming pool; and c) a signal transmitter and signal receiver for communicating a signal between the sensor and the controller so that the valve is selectively operated to replenish water upon detection of a low water condition by the sensor.
11. The control device of claim 10 wherein the controller comprises a programmable microprocessor.
12. The control device of claim 10 wherein the sensor comprises a float assembly having: a) a float member to be disposed within pool water; and b) a switch that is actuated to cause a signal to be transmitted from the signal transmitter in response to the float member becoming located at a predetermined position.
13. The control device of claim 10 wherein the sensor comprises a housing having a connector for removably affixing the housing to the lower side of a pool skimmer lid.
14. The control device of claim 10 further comprising a power supply for the controller.
15. The control device of claim 14 further comprising a solar panel for collecting and providing supplemental power to the controller.
16. The control device of claim 10 wherein the signal transmitted from the transmitter to the receiver is a radio frequency or microwave signal.
17. The control device of claim 10 wherein the signal transmitted from the transmitter to the receiver is any intelligence transmitted on the electromagnetic spectrum by modulating the specific frequency of interest (the target frequency).
18. The control device of claim 16 wherein the radio frequency signal is coded using dip switches to provide a relatively unique code.
19. The control device of claim 10 wherein the controller provides a predetermined fill period for maintaining a valve in an open position to replenish water in a pool.
20. A method of controlling water level in a pool, comprising: a) sensing the level of water in a pool; b) determining if a low water condition exists; c) transmitting a signal indicative of a low water condition; and d) selectively opening a valve in response to said signal to add water to the pool.
Description:
METHODS AND APPARATUS FOR CONTROL OF SWIMMING POOL WATER LEVEL This application claims priority of U. S. Provisional Application no. 60/142,373 filed on July 6,1999.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally methods and devices that are used to control liquid levels. In particular preferred embodiments described herein, the invention is directed to methods and devices used to control the level of water in a swimming pool.

2. Description of the Related Art Conventional swimming pools include systems for recirculating and replenishing the water in the pool. As the pool water is recirculated, it is typically filtered and cleaned and may also be heated, if desired.

Some pools have an automatic float level system. However, the majority of home pools do not have such a system for adding water to make up lost water due to evaporation and other causes. The home owner simply uses a garden hose from time to time to add water. This is time consuming and inconvenient. Pools that have an automatic water level system often rely upon one or more float valves that are associated directly with the inlets and outlets for water entering and leaving the pool. When the water level in the pool rises or falls, the floats mechanically actuate valves to cause water to enter or leave the pool. Examples of these mechanical types of systems are shown in U. S. Patents Nos. and 3,895,402.

Unfortunately, because the floats and valves of these systems are quite visible and located in or near the pool, they are vulnerable to damage or vandalism from swimmers.

The floats can be broken or rendered inoperable, thus negating the effectiveness of the system.

There are some systems known that incorporate a separate overflow tank or sump that is separate from the pool. The level of the water in the separate tank is used as an indicator of the level of water in the swimming pool. This separate tank is then monitored using a sensor, float, or other device. Examples of these types of systems are shown in U. S. Patent Nos. 402. These systems have the advantage of allowing the components necessary to measure the liquid level in the pool to be located away from the main pool. However, because a separate tank is required to be associated with the pool, these systems must be installed when the pool is originally constructed.

Otherwise, a retrofitting must be done wherein portions of the concrete surrounding the pool are broken up to install the separate tank and associated components. This can be costly and time-consuming and require that the pool be closed down during installation.

The present invention addresses the problem of the prior art.

SUMMARY OF THE INVENTION The present invention is directed to methods and apparatus that detect the level of water in a pool and control this level. In preferred embodiments, a water level sensor is unobtrusively located beneath the skimmer cap at one or more sides of the pool. The water level sensor includes a magnetic or electronic float switch and a radio frequency (RF) or infrared transmitter. A flow controller is remotely located away from the pool, is operably associated with a water inflow line that replenishes the pool water, and is electrically connected to a receiver that reads the transmitted signal from the float switch.

In a preferred embodiment, the flow controller actuates a valve that allows an external water supply to provide additional water to the pool.

The preferred embodiments described herein can be easily and inexpensively retrofitted to control the water level of a preexisting recirculation system for a pool.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically depicts a general pool recirculation system.

Figure 2 schematically illustrates a water level sensor and flow controller, in accordance with the present invention, operably associated with an exemplary recirculation system.

Figure 3 is an enlarged view of portions of the water level sensor.

Figure 4 is an isometric view of an alternative design for a exemplary water level sensor in accordance with the present invention.

Figure 5 illustrates an exemplary circuit board layout for components used in the water level sensor shown in Figure 4.

Figure 6 depicts a design for an exemplary receiver unit in accordance with the present invention.

Figure 7 is an exemplary circuit board layout for receiver components used in the receiver unit shown in Figure 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to Figure 1, a pool 10 is shown which contains an amount of water 12. The pool 10 has a number of skimmers 14 (one shown) that contain a skimmer basket used for removing larger impurities in the pool water. A water outflow line 16 is disposed below the skimmer 14 and extends to circulation pump 18. Water inflow line 20 extends from the circulation pump 18 back to the pool 10. It is common that both the inflow and outflow lines 20,16 are located below ground. In some instances, however, they are above ground. In operation, the circulation pump 18 draws water from the pool 12 through the outflow line 16 and pumps it through the inflow line 20 back into the pool 10. There may be one or more filters or other cleaners and perhaps a heater associated with this circulation system.

Referring now to Figures 2 and 3, an exemplary embodiment of the water level control system of the present invention is shown in a schematic fashion. The control

system includes a water level sensor 50 which is shown affixe by a bracket 51 to the bottom of a skimmer cap 52 of a type well-known in the art. The skimmer 14 includes a skimmer basket 54 which is used to remove impurities in water departing the skimmer 14 through outflow line 16.

The water level sensor 50 includes a magnetic or electronic float switch 56 which is surrounded by a static leveling tube 58 and disposed within the water 12. A magnetic or electronic float switch is a known device that can detect liquid levels. The float switch 56 preferably comprises a central rod 60 which carries a float member 62 which is slidably carried thereupon. Although not shown, it should be recognized that a small cantilever float might also be used for the float switch 56. Cantilever float is the type of float used in most toilet tanks wherein the float member is disposed on an arm that is pivotally affixed to a support. The arm is generally laterally oriented so that the float member rests in the water, and changes in the water level cause the arm to move angularly with respect to the support.

The central rod 60 of the float switch 56 shown also carries one or more electrical contacts (not shown) that cause the switch 56 to be closed or provide a signal when the float member 62 contacts it. The rod 60 may only have a single contact, however, there may be two such contacts--an upper contact and a lower contact. The lower contact would correspond to a point wherein the level of the water 12 has dropped to a point low enough that it is desired to add more water to the pool 10. The upper contact should correspond to a point wherein the level of the water 12 has risen to a point high enough that it is desired to stop adding water to the pool 10.

The leveling tube 58 serves the function of surrounding the float switch 56 to protect it from turbulent water conditions which might cause temporary fluctuations in the float switch 56. The tube 58 is mounted to the lower side of the skimmer cap 52.

However, it is open at the lower end to permit water 12 to enter and be communicated to the float switch 56. Also, holes 59 may be placed in the sidewall of the tube 58 to assure that the water level in the tube 58 is the same as that in the pool 10.

A transmitter 64 is mounted to the lower side of the skimmer cap 52 and is operably associated with the float switch 56. The transmitter 64 is capable of sending an

RF or infrared signal to a remote receiver 72 when the float member 62 slides up or down the float rod 60 to a predetermined point along the float rod 60, thus indicating that the level of water 12 has risen or fallen a predetermined amount. When this point is reached, the float switch 56 causes the transmitter 64 to transmit an RF or infrared signal 74. A power source (not shown) provides power to the float switch 56 and transmitter 64.

Power may be provided either by an internal battery (such as a 6 or 9 volt battery) or an external power source such as a solar power panel.

Although the exemplary transmitter 64 is described herein as transmitting an RF or infrared signal, those of skill in the art will understand that other types of wireless signals may be transmitted by the transmitter 64. Such alternative signals would include, for example, microwave signals. In a broad sense, the signal may comprise any intelligence transmitted on the electromagnetic spectrum by modulting the specific frequency of interest (the target frequency).

An RF or infrared receiving module 72 is adapted to receive the RF or infrared (or other) signal 74 transmitted by transmitter 64 and is located near circulation pump 18. It is noted that receivers and transmitters suitable for use as transmitter 64 and receiver 72 are known in the art. A control cable 76 operably interconnects the receiving module 72 to a solenoid valve 78 that, in turn, is installed to interconnect the water outflow line 16 to an external water source line 80. The external water source line 80 may be provided by, for example, a garden hose connected to a hydrant. The solenoid valve 78 can be opened, upon command by the module 72, to permit additional water from the external water supply 80 to enter the inflow line 20. Alternatively, the valve 78 can be closed to block flow from the source 80, but allow circulation through the water inflow line 20 which only returns to the pool 10 water that has been drawn by pump 18 through the outflow line 16. A filter 82 is also shown to be operationally interconnected with the inflow line 20.

In operation, the pool recirculation system operates to draw water 12 from the pool 10 through outflow line 16 via pump 18. The pump 18 then returns the water through inflow line 20 to the pool 10. When the amount of water 12 in the pool 10 drops (due to evaporation, splashing, or other reasons), the float member 62 travels downwardly

along the float rod 60 until the lower contact on the rod 60 is reached. Once this occurs, the transmitter 64 provides a signal 74 to the receiver unit 72 indicating that additional water is needed. The receiver 72 commands the valve 78 to open so that additional water from the external water supply line 80 is flowed into the inflow tube or the inflow line 20 and enters pool 10.

When the level of water 12 in the pool 10 has risen sufficiently so that the float member 62 has moved upwardly along the rod 60 and reached the upper contact, an RF or infrared signal 74 is provided from the transmitter 64 to the receiver 72 which, in turn, commands the valve 78 to close. When this occurs, the addition of more water to the pool 10 is altered. It is further pointed out that a number of variations are possible for actuation of the valve 78. For example, when the lower contact is contacted by the float member 62, a continuous signal can be provided from the transmitter 64 to the receiver 72. When the float member 62 moves vertically away from the lower contact due to increased water level, the continuous signal is altered so that the receiver 72 will command valve 78 to close.

Alternatively, the float switch 56 may incorporate only a lower contact with no upper contact. When the float member 62 contacts the lower contact, the valve 78 is opened for a predetermined amount of time which may be established by a timer element (which will be described shortly) in order to permit a substantially predetermined amount of water to be added to the pool 10.

Figures 4 illustrates an alternative, and currently preferred construction for an exemplary water level sensor 100 that may be used in the water level control system that is the subject of this invention. The water level sensor 100 includes a box-like outer housing 102 that defines an interior chamber 103. The housing 102 has a removably secured cover plate 104 at its lower end by screws or other connectors (not shown). Four legs 106 protrude upwardly from the upper end of the housing 102. The legs 106 each have a securing clamp 108 at their upper end that are designed to secure to a lateral rib 110 of a cover 112 for a pool skimmer, such as skimmer 14. The legs 106 may also be bonded to the ribs 110 or other parts of the cover 112 using glue or another bonding

agent. Alternatively, screws or other connectors might be used to affix the legs 106 to the cover 112.

The chamber 103 retains a circuit board 114 and a power source 116 that is operably interconnected with the circuit board 114 to supply power thereto. A suitable power source 116 is a 6 volt, gel-cell battery. The housing 102 is waterproof when the cover plate 104 is secured thereon so that the power source 116 and circuit board 114 are protected from water. Various encapsulation techniques for these components may be used to help prevent them from becoming wet and inoperable if immersed in the pool water 12.

At the lower end of the housing 102, a float assembly 118 projects downwardly.

The float assembly 118 includes a porous shell 120 that encloses a float member 122. The float member 122 is capable of upward and downward movement within the shell 120.

The float assembly 118 also has a magnetic switch (generally shown at 124) that is opened when the float member 122 is located above a predetermined position proximate the lower end of the shell 120 and closed when the switch 124 is at or below the predetermined position. Such a predetermined position is the position at which the float member 122 will be maintained during a low water condition when the water level sensor 100 is installed below a skimmer lid 112 and the float assembly 118 disposed within the water 12 of the pool 10.

Figure 5 depicts a layout for the circuit board 114 having components for generation of a transmitting signal. The operation of these components will only be described generally here, as such a description should be sufficient for one of ordinary skill in the art to understand their collective operation and integration on the board 114. The circuit board 114 contains a transmitter chip 126, processor 128, and a transmitting antenna 130. A voltage regulator 132 governs the amount of voltage provided to these components. There are also a set of terminals 134 for interconnection of the circuit board 114 with the power supply 116 and a set ofterminals 13 6 for interconnection of the circuit board 114 with the float assembly 118.

The transmitter chip 126 is of the type known in the art for sending out a radio frequency on-off signal transmit code. The transmitter chip 126 generates a unique code

or address for the signals it generates. The processor 128 is preferably an 8-bit processor that contains programming for the timing and encoding of the signals generated by the circuit board 114.

The water level sensor 100 transmits a signal to fill the pool 10 during a low water condition only during periods of non-activity. As a result, transient low water conditions, such as might be caused by swimmers disturbing the level of water 12, will not cause filling of the pool 10. When the water level in the pool 10 is sufficient (i. e., the float member 122 is located above the predetermined position in shell 120), the water level sensor 100 remains in a reduced power, sleep mode wherein only 3 microamps of power are drawn by the circuit board 114. When the float member 122 drops down to or below the predetermined position, due to a decrease in pool water level, the circuit board 114 will"wake up"out of its sleep mode and become active for transmission of a signal via antenna 130 to the receiver unit. If the float member 122 then drops to or below the predetermined position, the circuit board 114 returns to its sleep mode. It will be understood, then, that transient disturbances in the pool water 12, such as waves or splashing, will tend to cause the float member 122 to move upwardly and downwardly in a repeated fashion such that the circuit board 114 brought out of and back into a sleep mode.

During its normal operation, it is desired to filter out such transient disturbances so that the water level sensor 100 does not transmit a command requiring addition of water to the pool 10 in response to a transient lowering of the level of pool water 12.

Thus, the processor 128 contains timer circuitry ensuring that a signal indicating that the pool 10 must be filled is transmitted by the circuit board 114 only if the circuit board 114 has been active (taken out of its sleep mode) continuously for a predetermined amount of time. The predetermined amount of time is indicative of a low water condition for the pool 10 wherein the pool water 12 is not disturbed by splashing, wave action, or other transient disturbances. In a preferred embodiment, three minute period of inactivity will cause the circuit board 114 to operate to send a signal to fill the pool 10.

Figure 6 illustrates an exemplary receiver unit 150 that is operable to receive the signal generated by the water level sensor 100. The receiver unit 150 also functions as a

controller that provides selective control over opening and closing of the valve 78. The receiver unit 150 includes a weather-resistant housing 152 that is formed from a rear casing half 154 and a front casing half 156 that are hingedly affixed to one another. The rear casing half 154 is adapted to be secured to a wall or similar vertical support surface.

A bracket 158 supports solar power panel 160 atop the rear casing half 154.

The rear casing half 154 of the receiver unit 150 defines a recess 162 that houses a power supply 164 and a receiver board 166. As shown in Fig. 7, the receiver board 166 includes a programmable microprocessor 168 that controls the valve 78 and the timing sequences associated with filling the pool 10. A currently preferred processor 168 is a PIC 16C505 processor available from Linx Technologies, Inc., 575 S. E. Ashley Place, Grants Pass, Oregon 97526.

The transmitter chip 126 of the water level sensor 100 is programmed to transmit a signal that is coded using one among several codes available for a particular radio frequency. This code is permanently preprogrammed, and preferably, cannot be changed by the user. This permanent preprogramming is preferred because it allows the transmitter chip 126 to be sealed against moisture and fluids. Dip switches 170 on the receiver board 166, on the other hand, can be changed to one of several combinations to cause the receiver unit 150 to recognize signals having different codings. As a result, the receiver unit 150 can be set to receive the coded signal from the particular sensor 100 that it is sold with and further, the receiver unit 150 will not operate if it receives an improperly coded signal from another transmitter, such as that from a water level sensor used with a neighbor's pool. It should be understood that water level control systems may be marketed so that different units have sensors 100 with different discrete signal codes to eliminate the possibility that the same code will be used at adjoining residences, thereby reducing the chances of signal interference and cross-over.

The receiver board 166 also includes a number of diagnostic LED (light emitting diode) signal lights that become selectively lit to indicate certain conditions. LED 172 is a low battery indicator. During a low power condition from power supply 164, the receiver unit 150 becomes inoperable so that the valve 78 cannot be operated by the receiver unit 150. LED 174 lights to indicate that the valve 78 is in an open condition so

that the pool 10 is being filled. LED 176 lights to indicate a failure of valve 78. LED 178 lights to indicate excess time. A power switch 180 is provided, and LED 182 lights to indicate that the receiver board 166 is powered on. LED 184 indicates that the receiver board 166 is in a"test"mode (described shortly), and LED 186 indicates that a fuse (not shown) has broken or become inoperable.

An antenna 188 is operably interconnected with the receiving processor 168 for reception of a signal from the antenna 130 of the transmitting signal board 114.

As noted, the processor 168 governs timing for the filling sequences for the pool 10. In a currently preferred timing sequence, the processor 168 provides a predetermined fill period by commanding the valve 78 to remain open for ten (10) minutes, so that the water 12 in the pool 10 is replenished for a full 10 minutes upon detection by the water level sensor 100 of a low water condition. If the pool remains at a low water condition after the 10 minute fill period, a successive 10 minute fill period is initiated by the processor 168. If the water level sensor 100 again detects a low water condition, a third 10 minute fill period occurs, and so forth.

As a safety measure, the processor 168 automatically shuts-offthe valve 78 and prevents further filling after a predetermined accumulation of successive 10 minute fill periods to prevent overfilling of the pool 10. The three hour period should be considered to be a maximum cumulative fill time that is established by the processor 168 of the receiver unit 150.

The solar power panel 160 is used for recharging of the power supply 164 during daylight hours. If desired, the solar power panel 160 may also be interconnected to the board 166 to provide solar power to it directly for operation.

The water level control device can be placed in a standard operational mode or in "test"modes which are used to ensure that the device will operate properly in its operational mode. The water level control device is typically tested through two separate operations.

In the first of these operations, the water level sensor 100 is placed in a test mode and then located with respect to the receiver unit 150 to ensure that adequate transmission of the signal between the sensor 100 and the receiver unit 150 occurs without the signal

being blocked by objects or attentuated by distance. Next, the receiver unit 150 is placed into a test mode wherein the available address switch settings are determined. The water level sensor 100 is placed into its test mode by attaching a magnet to the float assembly 118 to activate or close the magnetic switch within the float assembly 118, thereby simulating a low water condition in the pool 10. Closing of the magnetic switch causes the transmitter circuit board 114 to transmit a coded signal to the receiver unit 150 indicating that the valve 78 must be turned on to flow water into the pool 10. The test LED 184 will become illuminated.

The receiver unit 150 is placed in a test mode when the dip switches 170 are all set to zero. In test mode, the receiver unit 150 is capable of identifying transmitter signal codes that are unavailable since they are in use by other devices, such as a duplicate pool water level device owned by neighbors or garage door openers. The receiver unit 150 can then be programme to utilize an available coded signal by placing the dip switches 170 to a setting that is not utilized by any of such other devices. It may be desirable when installing the water level control device to leave the receiver unit 150 of the device in the test mode for an extended period, such as 24 hours, to allow it a chance to detect coded signals from the surrounding area (such as a pool device or garage door opener in use at a neighbor's home).

It is noted that control systems of the present invention can be installed easily and inexpensively, as compared to conventional water level control systems. Generally, no digging is required, and no trenching is needed to bury wires or additional water lines between the pool and the circulation pump. The system is then easily retrofitted to an existing system. The invention provides the advantage of permitting the water level of a pool to be maintained while the owner is absent for a period of time since water is automatically added when needed by the system.

While the principles of the invention have now been made clear in an illustrative embodiment, it will be immediately obvious to those skilled in the art that many modifications of structure, arrangement, and components may be made without departing from those principles. Also, it should be recognized that the devices and methods of the present invention are not to be construed as limited only to use with swimming pools in that the levels in other bodies of water or even bodies of other liquids may be controlled using these devices and methods. Further, the invention is limited only by the following claims.