WO1991008530A1

WO1991008530A1 - Control apparatus

Info

Publication number: WO1991008530A1
Application number: PCT/AU1990/000579
Authority: WO
Inventors: Peter Parker
Original assignee: Peter Parker
Priority date: 1989-12-04
Filing date: 1990-12-04
Publication date: 1991-06-13

Abstract

Control apparatus (10) for controlling the level in a swimming pool (11) includes a level sensor (12) disposed within a liquid chamber (13), level control means (19) for controlling the level of liquid within the chamber (13) and communications means for operatively connecting said level sensor with said level control means such that the level of liquid within the chamber may be controlled to a desired level. Preferably, the liquid level sensor includes a pair of electrodes (14, 16) which may be exposed to contact with the liquid, and resistance measurement means for measuring changes in the resistance therebetween such that the presence of a liquid between the electrodes may be sensed. The control means (19) may include liquid inlet means (22) for increasing the liquid level or liquid outlet means (20) for decreasing the level. The control means (19) may further include timing means for operating the liquid inlet and/or outlet means (22, 20) for a preset time after energisation. The communications means may include a radio-telemetry link and the radio transmitter and receiver may be provided with encoding and decoding means which may include programming means such as switch banks whereby the coding may be easily changed during or after installation of the level control apparatus.

Description

"CONTROL APPARATUS"

This invention relates to control apparatus.

This invention has particular but not exclusive application to the control of the water level in swimming pools or the like, and for illustrative purposes reference will be made to such 5application. However, it is to be understood that this inventio could be used in other applications, such as industrial level control.

Swimming pools require constant attention to maintain the water level within the limits necessary for effective operation

♦ lOof the skimmer. Evaporation reduces the water level at a rate that varies widely with the weather, while rain increases the level. Various mechanical means of level control are available, but require extensive earthworks for their installation, as they require an auxiliary water chamber containing the level control lδapparatus to be installed at the same'water level as the pool.

The present invention aims to alleviate the above disadvantage and to provide control apparatus which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent. 0 With the foregoing and other objects in view, this invention in one aspect resides broadly in control apparatus including:- a level sensor disposed within a liquid chamber; level control means for controlling the level of liquid within said chamber; 5and communications means for operatively connecting said level sensor with said level control means such that the level of

SUBSTITUTESHEET liquid within the chamber may be controlled to a desired level.

Preferably, the liquid sensor includes a pair of electrodes which may be exposed to contact with the liquid, and resistance measurement means for measuring changes in the resistance Btherebetween such that the presence of a liquid between the electrodes may be sensed. A further electrode or electrodes may be provided, along with further resistance measurement means such that a change in liquid level above or below a desired level may be sensed. Of course, if desired, other liquid sensor means, 0such as a float activating a switch may be used.

The control means may include liquid inlet means for increasing the liquid level or liquid outlet means for decreasing the level. Preferably, however, the control means^' includes liquid inlet means, such as a solenoid valve or a pump disposed 5in a liquid supply line, as well as liquid outlet means such as a pump or solenoid valve connected between the liquid chamber and a drain whereby the liquid level may be increased or decreased as desired. The control means may further include timing means for operating the liquid inlet and/or outlet means for a preset time 0after energisation such that short-cycling of the apparatus may be minimised, or for disabling the liquid inlet and/or outlet means after a preset period of operation whereby excessive changes in water level as a result of malfunctions of the control apparatus may be minimised. 5 The communications means may include hard-wired control lines. However, it is preferred that the communications means include a radio-telemetry link such that electrical installation work may be minimised. The radio transmitter and receiver may be provided with encoding and decoding means such as tone, pulse width or digital encoding such that the response of the receiver to false alarms and extraneous transmitters may be minimised. 5Suitably, the encoding and decoding means includes programming means such as switch banks whereby the coding may be easily changed during or after installation of the level control apparatus.

In another aspect, this invention resides in a method of lOcontrolling the water level in a swimming pool, including:- placing a two-stage liquid level transmitter in the skimmer box thereof, said liquid level being programmed to transmit radio signals indicative of an increase or decrease in water level relative to the desired level; 5 connecting a first liquid level control means between a water inlet and the pool; connecting a second liquid level control means between a water outlet and the pool; and 0 connecting a receiver tunable to said radio signals to control said first and second level control means.

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of 5the invention, wherein:-

. FIG. 1 is a pictorial view of a control apparatus according to the invention; FIG. 2 is a schematic diagram of a level control transmitter according to the invention, and

FIG. 3 is a schematic diagram of receiver decoder/controller according to the invention. 5 The level control apparatus 10 shown in FIG. 1 is installed to control the water level in a swimming pool 11. A level sensing assembly 12 is mounted beneath the lid of the skimmer box 13, and contains circuitry of the type shown in FIG. 2. A water level greater than desired is sensed by the resistance change lObetween a common probe 14 and an upper probe 15, while a water level lower than desired is sensed by the change in resistance between the common probe 14 and a lower probe 16. Such changes in resistance control the transmitter circuitry to send a digitally-encoded radio signal, which is received by a radio 15receiver 17 within a controller housing 18.

On receipt of a digital code to which it has been programmed to respond, the controller 19 simultaneously operates a drain solenoid valve 20 and, via a suitable relay, the pool filter pump 21 in response to a "water high" signal, or operates an inlet 20solenoid valve 22 in response to a "water low" signal from the sensing assembly.

The drain solenoid valve 20 is connected between the pool filter pump discharge line 23 to the pool filter 24 and the filter backwash drain line 25 via a strainer 26. The strainer 26 25is intended to trap fine pool detritus that passes through the coarser strainer baskets in the skimmer box and pump inlet chamber, thus preventing any such material lodging on the drain solenoid valve seat. The non-return valve 27 is intended to prevent turbid backwash water from flowing back through the drain solenoid valve 20 into the filter during backwashing of the filter. 5 The inlet solenoid valve 22 is connected between a mains water point 28 and the outlet of the strainer 26 via an isolating- valve 29 and a vacuum breaker valve 30. Being connected to the outlet of the strainer rather than directly into the pump discharge line 23 it serves to cause backwashing of the strainer lOthus reducing the frequency of manual strainer cleaning operations.

In order that any of the above operations do not occur as a result of a transient change in water level, the level sensing assembly 12 requires that a level change above the upper probe 15 5or below the lower probe 16 be maintained for a set period of time before transmitting a signal to the controller.

In order that excessive filling of the pool as a result of water leaks in the pool or associated plumbing does not go unnoticed an alarm flashes after every 9 filling operations. The 0alarm is reset by switching the controller off and on again and if its activation becomes abnormally frequent it is indicative of a possible pool leak..

Additional apparatus such as lights, spa blowers, external speakers etc can be operated remotely by the controller 21 using 5a hand held transmitter set to the same transmitting code as the level sensing assembly and the controller. The additional apparatus is powered via either of the two auxiliary relays (see Fig 3 ) .

Three versions of the controller are available, being: a. pool fill only; b. pool drain only; and 5c. pool fill and drain.

Versions a and b can be field upgraded to version c. The remotely operated auxiliaries facility is optional for all versions.

It will of course be realised that while the above has been lOgiven by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is defined in the appended claims.

15

Claims

THE CLAIMS DEFINING THIS INVENTION ARE AS FOLLOWS;-

1. Control apparatus including:- a level sensor disposable within a liquid chamber; level control means for controlling the level of liquid within said chamber; and communications means for operatively connecting said level sensor with said level control means.

2. Control apparatus as claimed in claim 1, wherein the liquid sensor includes a pair of electrodes which may be exposed to contact with the liquid, and resistance measurement means for measuring changes in the resistance therebetween such that the presence of a liquid between the electrodes may be sensed.

3. Control apparatus as claimed in claim 1 or claim 2, wherein the a further electrode or electrodes and further resistance measurement means are provided such that a change in liquid level above or below a desired level may be sensed.

4. Control apparatus as claimed in any one of the preceding claims, wherein the control means includes liquid inlet means, whereby the liquid level may be selectively increased or decreased.

5. Control apparatus as claimed in any one of the preceding claims, wherein the control means includes timing means for operating the liquid inlet and/or outlet means for a preset time after energisation.

6. Control apparatus as claimed in any one of the preceding claims, wherein the communications means include a radio- telemetry link.

7. Control apparatus as claimed in claim 6, wherein the radio transmitter and receiver are provided with encoding and decoding means such as tone, pulse width or digital encoding.

8. Control apparatus as claimed in any one of claims 6 or 7, wherein the decoding means includes programming means such as switch banks whereby the coding may be easily changed during or after installation of the level control apparatus.

9. A method of controlling the water level in a swimming pool, including:- placing a two-stage liquid level transmitter in the skimmer box thereof, said liquid level being programmed to transmit radio signals indicative of an increase or decrease in water level relative to the desired level; connecting a first liquid level control means between a water inlet and the pool; connecting a second liquid level control means between a water outlet and the pool; and connecting a receiver tunable to said radio signals to control said first and second level control means.

10. Control apparatus substantially as hereinbefore described with reference to any one of the accompanying drawings.