GB2368703A

GB2368703A - Leak detection system controlling valve to cease liquid flow

Info

Publication number: GB2368703A
Application number: GB0014492A
Authority: GB
Inventors: Terence Martin Pierson; Colin Terence Westwood
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-06-15
Filing date: 2000-06-15
Publication date: 2002-05-08
Also published as: GB0014492D0

Abstract

A system which senses a flood or leak, including a flip-flop element 14 which activates an electrical solenoid 13 to close a valve 8 upon reception of signal from detector 7 sensing the leak or flood condition and remains closed if the solenoid is no longer energised which may occur in the event of loss of the electricity supply. The valve may be subsequently re-opened by operating a resetting device 21.

Description

APPARATUS AND METHOD FOR FLOOD OR LEAK CONTROL This invention relates to a system for closing one or more liquid-flow control valves in the event of a flood or leak.

It is known to provide in domestic premises a system including sensors and valves to cut off the supply of water in the event that a water flood is detected. US-A-4324268 discloses an automatic flood control valve apparatus having a normally open, water supply control valve, an electrical latching relay for holding the valve in a closed condition when the relay is energised and until it is manually reset, and a single transistor sensor circuit for energising the relay in response to a flood. This system has a major disadvantage in that if there is an electrical power cut subsequent to a flood the valve will reopen the water supply and the flood will recommence.

According to a first aspect of the present invention, there is provided apparatus for sensing a flood or leak and discontinuing supply of liquid in response to a flood or leak, comprising a liquid-flow control valve having open and closed conditions, a sensor for sensing a flood or leak, electrical driving means for operating said valve, electrical power supply means connected to said electrical driving means for energising the same to result in closing of said valve in response to said sensor sensing a flood or leak, whereupon said valve remains in said closed condition even if said supply means ceases supplying electrical power to said electrical driving means, and resulting means for resetting said valve from said closed condition to said open position.

According to a second aspect of the present invention there is provided a method comprising passing liquid through a liquid-flow control valve, sensing a flood or leak, energising electrical driving means in response to the sensing of said flood or leak to cause said valve to move from an open condition to a closed condition to prevent the passing of said liquid through said valve, said valve then remaining in said closed condition even if said electrical driving means is de-energised, and resetting said valve from

said closed condition to said open condition.

Owing to these aspects of the invention it is possible to provide a flood or leak detection system that after detection of a flood or leak is not dependent upon the supply of electrical power to keep the liquid supply shut off.

The valve preferably takes the form of a flip-flop valve, i. e. one which is stable in both its open and its closed conditions.

Advantageously, the signals from the sensor are processed by associated circuitry that contains more than one transistor, for example two transistors, for increased sensitivity. A variable resistor is advantageously included in that circuitry to permit adjustment of sensitivity by the installer or user of the system. The circuitry can also contain visual and/or audible indicators to confirm the status of the sensor, preferably a green light indicating no flood or leak and a red light and buzzer or bell that operate to indicate that a flood or leak has been detected. The resetting means may be a reset button the pressing of which causes the electrical driving means to return the valve to its open condition. In a preferred embodiment the electrical driving means is connected via the circuitry to a plurality of sensors in different positions around premises being protected. If desired, the sensitivities of the respective sensors can be adjustable independently of each other by an installer or a user. Also, if desired, the sensitivity of the or each sensor in one room of a building could be different from that of the or each sensor in another room. The circuitry may be powered from a mains electricity supply or a (12 volt) battery.

In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic view of a house in which is installed a system for sensing a flood or leak and discontinuing water supply in response to a flood or leak, Figure 2 is a diagrammatic section through a valve of the system, the valve being in open condition,

Figure 3 is a view similar to Figure 2 of the valve in closed condition, and Figure 4 is a diagram of electrical circuitry of the system.

Referring to Figure 1, the house 1 contains a water supply installation supplying water to a number of appliances that are required to be supplied with water including a cold water tank 2, a hot water cylinder 3, a bath 4, a radiator 5 and kitchen appliances 6. A number of sensors 7 are positioned close to the appliances. These sensors 7 are designed to detect the presence of water when it is flooding or leaking from the appliances. Each sensor 7 is of the form of two wires that are in a complete circuit except for the gap between them; the presence of water between the two wires closes the circuit and via electrical circuitry at control panel 9 results in the closure of an appropriate valve 8.

Figures 2 and 3 show the valve 8 in its open and closed conditions. The water flows through a supply pipe 10 in the direction of the arrows A and in the condition of Figure 2 its flow is not obstructed, because a closure plunger 11 thereof, fixed to a diaphragm 12 thereof, is held open by water pressure. When a sensor 7 detects a leak or flood, a solenoid 13 is energised to create a magnetic field that acts on a spring-loaded armature 13a to push the plunger 11 into its closed condition (Figure 3), where the plunger 11 is held in place by the force of the spring 13b acting on the armature 13a, shutting off the water supply. Continued energisation of the solenoid 13 is not required to hold the plunger 11 closed: the spring pressure serves that function.

Once the plunger 11 is in the condition as shown in Figure 3 it will not open until the polarity of the power is reversed through the solenoid 13 thereby creating an opposite magnetic field that returns the armature 13a to the position shown in Figure 2, whereby the pressure of the water on the diaphragm 12 can return the plunger 11 to its open position shown in Figure 2.

Figure 4 shows the electrical circuitry that controls a single sensor 7 and its associated valve 8.

Further sensors 7 and/or further solenoids 13 (each controlling its own valve 8) may be connected in the circuitry of Figure 4, or a plurality of independent circuits each according to Figure 4 may be provided. When water activates the sensor 7, a circuit 20 containing a variable resistor 22 is closed and the solenoid 23 of the relay 14 is energised via the transistors 15. This opens a circuit 16 containing a green light-emitter 17 and closes a circuit 18 which contains a red light-emitter 19 and the solenoid 13.

The solenoid 13 then operates its associated valve 8, shutting off the supply of water. Even if the sensor 7 dries out, the solenoid 13 will not be activated to return the plunger 11 to its open position until the press-operated button manual reset switch 21 is operated which reverses the polarity of the power across the solenoid thereby returning the plunger 11 to its open condition.

Claims

CLAIMS 1. Apparatus for sensing a flood or leak and discontinuing supply of liquid in response to a flood or leak, comprising a liquid-flow control valve having open and closed conditions, a sensor for sensing a flood or leak, electrical driving means for operating said valve, electrical power supply means connected to said electrical driving means for energising the same to result in closing of said valve in response to said sensor sensing a flood or leak, whereupon said valve remains in said closed condition even if said supply means ceases supplying electrical power to said electrical driving means, and resetting means for resetting said valve from said closed condition to said open position.
2. Apparatus according to claim 1, wherein said valve takes the form of a flip-flop valve.
3. Apparatus according to claim 1 or 2, wherein the sensitivity of said sensor is adjustable.
4. Apparatus according to claim 1,2 or 3, and further comprising signal-processing circuitry associated with the output of said sensor.
5. Apparatus according to claim 4 as appended to claim 3, wherein said circuitry includes a variable resistor to permit adjustment of sensitivity of said sensor.
6. Apparatus according to claim 4 or 5, wherein said circuitry contains more than one transistor, to give relatively good sensitivity.
7. Apparatus according to claim 4,5, or 6, wherein said circuitry contains visual and/or audible indicators to confirm the status of the sensor.
8. Apparatus according to any one of claims 4 to 7, and further comprising at least one other sensor with which the circuitry is associated, the sensors being located in different positions around premises being protected.
9. Apparatus according to claim 8 as appended to claim 3, wherein the sensitivities of the respective sensors are adjustable independently of each other.
10. Apparatus according to claim 9 or 10, wherein the sensitivities of the respective sensors are different from

each other.
11. Apparatus according to any preceding claim, wherein said resetting means comprises a reset button the pressing of which causes the electrical driving means to return the valve to its open condition.
12. A method comprising passing liquid through a liquid-flow control valve, sensing a flood or leak, energising electrical driving means in response to the sensing of said flood or leak to cause said valve to move from an open condition to a closed condition to prevent the passing of said liquid through said valve, said valve then remaining in said closed condition even if said electrical driving means is deenergised, and resetting said valve from said closed condition to said open condition.
13. A method according to claim 12, and further comprising adjusting the sensitivity of said sensing.
14. A method according to claim 12 or 13, wherein said sensing is performed in different positions around premises being protected.
15. A method according to claim 14 as appended to claim 13, and further comprising adjusting the sensitivities of said sensing at the respective positions independently of each other.
16. A method according to claim 14 or 15, wherein the sensitivities of said sensing at the respective positions are different from each other.
17. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.
18. A method substantially as hereinbefore described with reference to the accompanying drawings.