IE20040327U1 - Apparatus and method for leak detection and prevention - Google Patents

Abstract

ABSTRACT An apparatus for leak detection and prevention comprises an electrically actuable shut—off valve (1 1) for connection to a water mains inlet pipe (P) and an associated fluid flow detector (12) for monitoring flow into a water circuit. The apparatus further compn ses a controller (30) for determining fluid flow rates past the flow detector (12) and for providing a drive signal to the shut—off valve (1 1). The shut-off valve (1 1) is of the normally—closed type so that in the absence of power, the water circuit is isolated from the mains supply. A second electrically actuable valve (21) is provided for connection to a storage vessel or tank (V), so that upon detection of a leak, the valve (21) is opened to drain a volume of water from the storage vessel or tank (V) in the water circuit. A method for leak detection and prevention is also disclosed.

Description

APPARATUS AND METHOD FOR LEAK DETECTION AND PREVENTION Field of the Invention The present invention relates to an apparatus and method for leak detection and prevention and more particularly to the Control of a water mains shut—off valve operable in leak conditions. Additionally, the invention relates to implementing said leak detection and prevention and also is directed to an improved shut-off valve system.

Background to the Invention It will be a reciated bv the skilled addressee that the invention, although PP . a . , - primarily directed to the detection and preventio‘n of leaks in domestic buildings having water circuits fed from mains water supplies, can‘ be adopted for use in I .. ‘ commercial premises and in connection with other open and closed water circuits.

Any references hereinafter to domestic buildings or water systems should be taken as non-limiting.

Most individuals are familiar with the damage that can be caused by a leak in the home or office environment. One of the most problematic issues is that when a premises is left unattended and a leak occurs, the only limit to the amount of water flowing is the physical size of the hole or crack causing the leak, the water pressure at the leak and the time the leak is left unattended.

Generally, leaks occur due to one of three major causes. Firstly, leaks can be caused by accidental damage such as drilling a hole in the wrong location, flexing of pipes against unsecured floor boards and a host of other reasons. However, in each case the leak occurs when the premises is occupied and a mains stop-cock can be turned to isolate the water circuit quickly. Depending on the location of the leak (or in which water circuit the leak occurs), a head of water might be available to flow from the leak. This head of water is normally from a sizeable storage tank in the attic of a residence or on the roof of an apanment block or other building. In this case, toilets may be flushediand water taps opened to relieve the head of water. Secondly, wear or age is a major contributing cause of leaks and these leaks can develop at any time, whether an owner or resident is present or absent. Thirdly, frost damage and burst pipes caused by ice expanding in an enclosed space can have a devastating potential for leak and water damage.

Again, this can occur whether the building is occupied or vacant although it is more likely to occur in a vacant property or one where little or no heating is used.

In each of the above scenarios, the potential for damage is great and where structured damage occurs, including sodden ceilings. there is a risk of severe or fatal injury.

In attempt to address the known problem, numerous attempts have been made to find an effective solution. Most solutions involve the automated actuation of a shut-off valve. however, few take a realistic overview of the potential leak causes and resultant damage.

In an attempt to obviate some of the disadvantages highlighted above, a solution suggested in the prior art is to use moisture detectors or fluid leakage sensors in various rooms throughout a building. The sensors may be positioned adjacent or below potential leakage points, such as radiators, baths. sinks, washing machines and the like, and are connected to an electronic control unit which registers the leak and provides a drive signal to a solenoid valve to isolate the incoming water mains.

Exemplary of such arrangements are GB 2 223 613 to Bamish and GB 2 202 358 to Dawe. In each case strategically placed sensors are connected to a control unit which in turn is connected to a solenoid valve. There are a number of well- appreciated disadvantages associated with these prior art arrangements which make them unpopular. Firstly, there is a significant amount of wiring required to connect the leak detectors to a central control unit and, secondly, the sensors can be slow to react to a leak. Often a significant amount of water from a leak can be absorbed into carpets. floorboards and floor spaces and it is not until a ceiling starts to sag that visual evidence ofa leak obviates the leak detectors.

It will be appreciated therefore that if the detectors/sensors are not correctly positioned, the solution may provide a false sense of protection.

Other suggested solutions measure fluid throughput and upon pre-determined criteria, close a solenoid valve. One example of this prior art is GB 2 360 365 to Smith where a controller receives a signal from a flow sensor mounted on the mains water pipe to close a solenoid—0perated valve when there has been continuous flow for a set period or above an authorised flow threshold.

It is an object of the present invention to provide an apparatus for leak detection and prevention that seeks to alleviate the disadvantages associated with the prior art.

It is an object of the present invention to provide a water main shut—off valve arrangement which easily fitted into existing water circuits.

It is a further object of the invention to provide an improved method of leak detection and prevention.

Summary of the invention Accordingly, the present invention provides an apparatus for leak detection and prevention, the apparatus comprising: an electrically actuable shut-off valve for connection to a water mains inlet pipe; a fluid flow detector for monitoring flow into a water circuit; and P3291 |E040‘327 a controller for determining fluid flow rates past the flow detector and for providing a drive signal to the shut-off valve. in which the shut-off valve is of the norrnally-closed type so that in the absence of power, the water circuit is isolated from the mains supply.

This arrangement ensures that the apparatus is inherently fail-safe and in a condition where a leak causes the building electricity supply inadvertently to be isolated, the water mains supply also will be isolated.

Advantageously, the apparatus includes a further electrically actuable valve for connection to a storage vessel or tank, so that upon detection of a leak, the valve can be opened to drain a volume of water from the storage vessel or tank in the water circuit.

This arrangement ensures that the head of water used for moving water around the water circuit of a building may be drained externally of the building and does not provide further water for the leak or pressure to drive water through the hole or crack forming the leak.

Conveniently, the controller includes a user interface having a setting switch for selecting one of a number of functions of the controller.

Advantageously, the controller includes a timer so that upon enabling the controller, a preset period is allowed for water flow within the water circuit to reach a steady state.

This arrangement allows for activation of the unit upon leaving a building, for example, over a weekend or for a longer period, without the apparatus inadvertently being activated. If a family are leaving their home for a holiday. it is likely that at least one family member will use a toilet before departing which will mean that water may still be flowing in the water circuit when the family wishes to depart. Rather than waiting for the circuit to reach a steady state before activating the leak detection and prevention apparatus, a timer permits a flow of water past the flow detector for a given period. After that period has elapsed any P329./ES |E040327 fluid flow (or threshold fluid flow) will cause the controller to close the inlet valve and open the drain valve.

In one arrangement the controller includes an emergency switch which when activates enables the controller to close the inlet shut—off valve and to open the storage vessel drain valve.

The apparatus includes a manual override or by-pass means so that water flow within the water circuit is maintained in an override mode.

The present invention further provides a method for leak detection and prevention including: monitoring flow from a mains water supply into a water circuit; comparing water flow with a controller setting to detect a leak; closing an inlet valve to prevent mains water entering the water circuit: opening a drain valve to release Water from a storage vessel within the water circuit.

Conveniently, the method includes allowing water flow within the water circuit to reach a steady state before comparing with the or each controller setting.

Brief Description of the Drawings The invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only, one embodiment of apparatus for leak detection and prevention in accordance with the invention.

In the drawings: Figure l is a schematic elevation ofa mains shut-off valve, a flow detector switch and by-pass path arrangement; P329./ES IE 040327 Figure 2 is a schematic elevation of a water storage vessel having a drain path opened and closed by a “normally closed” drain valve; Figure 3 is a schematic circuit diagram of a controller; and Figure 4 is a front elevation of a switch face of the controller.

Detailed Description of the Drawings Referring to the drawings and initially to Figure 1, a mains water inlet pipe P is terminated by stopcock S, normally located within a building, for example, a domestic residence. The apparatus of the invention is suitable for retro-fitting by replacing a short section of the domestic side of the inlet pipe with an assembly 10 comprising an electrically actuable (solenoid) shut-off valve 11 and a flow switch 12 on a direct path 15 and. on a by-pass path 16, having a manually operable valve 19. The assembly 10 is constructed as a relatively short length for convenient fitting, for example, beneath a sink unit at the point where the mains stopcock S is often located.

Referring now to Figure 2, a water storage vessel V is fed via the assembly 10 from the mains supply. The vessel V is modified to include a drain outlet 20 which is normally closed by an electrically actuated (solenoid) drain valve 21.

The solenoid actuation of the inlet valve 11 and the drain valve 21 are connected to a controller unit 30 comprising a relay 32, a timer 33, a function switch 34 and an emergency push—button switch 35, as illustrated in Figures 3 and 4. Electrical mains power is provided to the controller unit 30 on positive (Fl-ve), neutral (-ve) and earth (gnd) rails. The earth (gnd) rail is assumed to be linked to the pipework making up the water circuit and in accordance with local and/or regional regulations. The neutral (-ve) rail connects to each of the solenoids 1 l, 21 as their respective return paths. The positive (+ve) rail is switched through the function switch 34 to provide four positions corresponding to the required modes. however, at all times when the relay 32 is not energised, power is fed to the inlet valve solenoid 1 1, keeping it open.

In the RESET position, power is isolated from energising side of the relay, however, the relay 32 position ensures the inlet solenoid ll maintains its connection to the mains voltage, that is in an open position, whereas the drain valve remains in its "normally closed” position.

Assuming the main stopcock S is open and the manually operable b_v-pass valve 19 is closed, when the switch 34 is turned to the ON position, power is fed to the timer 33 which counts a predetermined period beforeconnecting the power to the How switch l2. If after this period, the flow"has not stopped (or optionally, does not exceed a predetermined set point), the flow switch 12 communicates the mains power along a return path to the relay 32 which switches state. disconnecting power from the inlet valve solenoid 11 and preventing flow into the water circuit. At the same time, the relay connects power to the drain solenoid El which opens allowing the contents of the storage vessel to drain externally of the building through its outlet 20.

In the STANDBY position. the function switch 34 brings the push—button switch into circuit. When the button 35 is pressed, the relay 32 disconnects the inlet solenoid 11 and connects the drain solenoid 21, isolating and draining the water circuit as before. In the OFF position. power is directed only to the inlet solenoid ll, reverting the water circuit effectively to its pre-installation configuration.

However, if a leak were to occur in the OFF position which shorted the electrical mains, the inlet shut-off valve ll would revert to its "normally closed" position. providing a measure of leak prevention.

It will be appreciated that the terms used herein are intended to be of a general nature and should not be construed as limited to the specific use described.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only. and that various modifications and alterations are possible within the scope of the appended claims.

P339./ES

Claims (5)

1. An apparatus for leak detection and prevention, the apparatus comprising: an electrically actuable shut—off valve for connection to a water mains inlet Pipe; a fluid flow detector for monitoring flow into a water circuit; and a controller for determining fluid flow rates past the flow detector and for providing a drive signal to the shut-off valve. in which the shut-off Valve is of the normally-closed type so that in the absence of power, the water circuit is isolated from the mains supply.

2. An apparatus for leak detection and prevention as claimed in Claim 1, in which the apparatus includes a second electrically actuable valve for connection to :1 storage vessel or tank, so that upon detection of a leak. the valve is opened to drain a volume of water from the storage vessel or tank in the water circuit.

. An apparatus for leak detection and prevention as claimed in Claim l or Claim K4) 2, in which the apparatus includes one or more of: a timer so that upon enabling the controller, a preset period is allowed for water flow within the water circuit to reach a steady state; an emergency switch which when activates enables the controller to close the inlet shut-off valve and to open the storage vessel drain valve; and a manual override or by-pass means so that water flow within the water circuit is maintained in an override mode.

4. A method for leak detection and prevention including: monitoring flow from a mains water supply into a water circuit; comparing water flow with a controller setting to detect a leak; closing an inlet Valve to prevent mains water entering the water circuit; and opening a drain valve to release water from. a storage vessel within the water circuit.

5. An apparatus and method for leak detection and prevention substantially as herein described, with reference to and as shown in the accompanying drawings.