FLUID SHUT-OFF SYSTEM
The present invention relates to an automated fluid shut-off system and in particular, but not exclusively, to an automated gas shut-off system.
In present day fluid supply installations, fluids such as gas and water are tapped from a main supply and flowed directly into a premises to appliances therein via pipes or hoses or the like. If the installation is operating correctly and safely then the fluid will only flow when an appliance within the premises is operating. However, if a fault should occur in the installation such as a leak in a pipe or a faulty valve at or on an appliance then the fluid would spill into the premises and would continue to do so until the spillage was detected and the flow turned off at a main supply valve.
Such leaks can cause enormous damage to premises and property which can give rise to substantial costs for repair. One of the most dangerous spillages and one which is capable of causing perhaps the most damage is the spillage of gas due to its explosive properties; a build up of gas can ignite and explode with such force that it can destroy entire buildings. Such gas explosions have also resulted in a number of fatalities, caused by the likes of a gas build up being ignited by an electrical spark from an
automatic timed central heating system or even a simple light switch.
It is an object of the present invention to obviate or at least mitigate these problems by providing a fluid shutoff system which will only allow the flow of a fluid into a premises on demand, thus preventing the build up of the fluid in the premises for example from a faulty fixture.
According to one aspect of the present invention there is provided an automated fluid shut-off system comprising means for controlling the supply of a fluid to a premises wherein said controlling means allows the fluid to flow into the premises only when said fluid is required therein.
According to another aspect of the present invention, there is provided an automated fluid shut-off system comprising: switching means for detecting a demand for fluid when a respective at least one appliance located within a premises is activated, said appliance being supplied with a fluid via a supply conduit; and a valve adapted for connecting to the supply conduit for controlling the flow of said fluid; wherein the valve opens in response to a demand for the fluid from within the premises indicated by the switching means, and closes when the demand for the fluid is eliminated indicated by the switching means.
According to another aspect of the present invention
there is provided an automated fluid shut-off system comprising : switching means for initiating a signal when a respective at least one appliance located in a premises is activated, said appliance being supplied with a fluid via a supply conduit; a valve adapted for connecting to the supply conduit for controlling the flow of said fluid; and flow detecting means associated with the supply conduit for detecting fluid transfer therein; wherein the valve is located out with the premises and opens in response to a signal communicated from the switching means, indicating a demand for the fluid from within the premises; and closes in response to a signal communicated from the flow detecting means, indicating an elimination of the demand for the fluid within the premises.
The automated fluid shut-off system operates such that a demand for fluid by an appliance initiates a signal which is transmitted from the switching means to the valve, which opens, allowing the flow of the fluid to the appliance.When the appliance is switched off, whether manually or automatically, the stoppage of the flow is detected by the switching means and/or the flow detecting means which initiates a signal to the valve, causing the valve to close.
The present invention therefore prevents unnecessary or accidental flow of the fluid into the premises caused by a leak or a fault at any point downstream of the valve.
This minimises the possibility of flooding, or where the fluid is flammable, the possibility of fire or explosion.
In this way, the system may act as a leak detection system in that if a leak of fluid has occurred while no demand for the fluid is indicated then the valve will close or remain in a closed position. An indicator device may be included which may provide an audible or visual signal indicating that a leak has occurred, allowing the system to be examined by an engineer or the like to detect the leak. and make the required repairs in order to render the installation safe for use. For this purpose, an override. plunger may be fitted to the system to re-pressurise the installation.
Preferably the fluid shut-off system is for use with a supply of gas which may be supplied from a domestic gas supply, industrial gas supply or from storage containers and the like. It would be understood by those of skill in the art that the system could be used with a supply of a range of fluids such as water and oil and the like.
The present invention has particular application in domestic households as a gas shut-off system wherein the valve would be located out with the household and would only allow gas to flow when it is required therein. This
has huge benefits in the prevention of catastrophic explosions due to faulty or damaged pipes and appliances, for example.
Preferably the at least one appliance is a gas appliance such as a boiler, heater, cooker or the like which require gas for operation and are supplied by gas via a supply conduit. Generally, the at least one appliance may be any appropriate appliance which makes use of the particular fluid being supplied.
Conveniently the fluid shut-off system can be incorporated into a fluid supply wherein the fluid is fed to a number of appliances within the premises.
Preferably the switching means associated with a respective at least one appliance is a normally open switch which is activated when the respective at least one appliance is switched on, creating a demand for the fluid.
The switching means may be a reed switch, for example, which will close to indicate a demand for fluid.
Conveniently the flow detecting means is integrated into the pipeline feeding the at least one appliance. The flow detecting means may be for example a flow transducer or a volume flow sensor or the like.
It is preferred that the flow detecting means is sufficiently sensitive to distinguish between a large range of flow rates such as a high flow rate where an appliance is switched on to a considerable extent, zero flow rate
when an appliance is switched off and a very low flow rate similar to that required by a boiler pilot light or a gas heater or cooker on a minimum setting. This allows the flow controlling means to successfully operate in a system where a large range of appliances are involved.
Preferably the valve is an electrically operated valve such as a motorised gas valve, integrated into the supply conduit feeding the at least one appliance. The valve may for example operate on a voltage of 240 V or 24 V.
More preferably, the valve is a double block valve assembly.
A preferred location of the valve is upstream of the flow detecting means, and as mentioned hereinbefore positioned out with the premises. Alternatively the valve may be positioned downstream of the flow detecting means provided that the valve and flow detecting means are connected via an untapped conduit so that only flow through the valve is detected.
Preferably the fluid shut-off system further comprises system controlling means which may comprise a central processing unit (CPU) or a programmable logic controller (PLC) and associated circuitry to which the switching means and/or flow detecting means, valve and power supply are connected.
Alternatively, the system controlling means may comprise a programmable relay and associated circuitry to
which the appropriate components of the system are connected.
The system controlling means may alternatively comprise a simple circuit of which the switching means and/or flow detecting means, valve and power supply are a part.
The system power supply may be a mains power supply, and where necessary a transformer may be utilised to step down or even step up the voltage. Additionally rectifying means may be used to provide a D. C. voltage from an A. C. supply. Alternatively, or in addition to for backup in the event of a power failure, power may be supplied by a battery.
The switching means and/or flow detecting means and valve may be in communication using electrically conducting wires, for example. Alternatively, the switching means and/or flow detecting means and valve may be in communication using radio frequencies. In this case, in order to prevent the radio frequency of one system interfering with that of another system, the alteration of the frequency may be made using a key pad interface, for example.
In one embodiment of the present invention, the system may be associated with a fire detection system, such that, if a fire is detected within a premises, the valve will be activated to close to prevent further fluid flow, which in
the case of a gas supply would prevent explosion and eliminate fuelling the fire.
Preferably, the automated fluid shut-off system further comprises a manual override to allow operations such as tightness testing and purging and the like to be carried out, and to enable the fluid installation to be operational in the event of a power cut, for exampleAccording to a further aspect of the present invention there is provided a method of supplying a fluid to a premises via a supply conduit on demand, the method comprising the step of automatically opening a valve allowing the passage of the fluid into the premises when an appliance therein requiring the fluid is activated.
According to a still further aspect of the present invention there is provided a method of preventing a fluid from flowing into a premises via a supply conduit when demand for the fluid is eliminated, the method comprising the step of automatically closing a valve preventing the passage of the fluid into a premises when an appliance therein consuming the fluid is switched off.
These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:Figure 1 is a representation of an automated gas shutoff system in accordance with one embodiment of the present invention;
Figure 2 is a further representation of the system shown in Figure 1 ; Figure 3 is a representation of an automated gas shutoff system in accordance with an alternative embodiment of the present invention; andFigure 4 is a representation of an automated gas shutoff system in accordance with another embodiment of the present invention.
Referring initially to Figure 1 there is shown a gas shut off system 100 having two gas appliances, the first being a boiler 102 and the second being a cooker 104, which are supplied by gas through conduit 106. Associated with. the boiler and cooker appliances 102,104 are sensors 108, 110 respectively, which sensors 108,110 each comprise a reed switch which closes when the respective appliance 102, 104 is switched on creating a demand for gas. When the reed switch is closed a radio frequency signal is transmitted to a central processing unit (CPU), which in turn transmits a signal to a double block valve assembly 114 located in the gas supply conduit 106 at a position out with a premises (not shown), causing the valve 114 to open, thus providing the required supply of gas. When the appliance 102,104 is switched off, the signal being transmitted between the respective sensor 108,110 is terminated and the valve 114 is therefore signalled by theCPU 112 to close and thus shut-off the supply of gas. In
the embodiment shown in Figure 1, the system 100 is operated by a mains power supply 116.
Referring now to Figure 2, a more general representation of the system of Figure 1 is shown. Sensors 108,110 are shown in an open position which indicates that the valve assembly 114 is closed and thus no gas is flowing. Upon activation of at least one of the sensors, the CPU 112 will signal the valve assembly 114 to open, causing a flow of gas.
Reference is now made to Figure 3 which shows an automated gas shut-off system 10 in accordance with an alternative embodiment of the present invention wherein the system 10 only allows the flow of gas 12 into a premises (not shown) via a pipeline 14 when the gas 12 is in demand by an appliance 16.
The gas shut-off system 10 comprises a normally open switch 18 which is associated with the appliance 16 and is activated when the appliance 16 is switched on. The system 10 also comprises a 240 V D. C. motorised gas valve 20 positioned out with the premises and a flow detector 22 which are both integrated into the pipeline 14. The flow detector 22 is positioned downstream of the valve 20 and is electronically normally open, that is the detector 22 acts as an electronic switch which is open when the gas 12 is flowing and makes a circuit or closes when the flow of gas 12 stops.
The system 10 is powered by a 240 V A. C. power supply 24 and is controlled by a programmable logic controller (PLC) 26 to which the switch 18, valve 20, flow detector 22 and the power supply 24 are all connected via cables 28.
A typical operation of the system 10 will now be described with reference to Figure 1. When the appliance 10 is switched on the switch 18 is activated which initiates a signal creating an input X2 into the PLC 26.
On input X2 the PLC 26 relays an output Yl to the valve 20 which opens thus allowing the gas 12 to flow to the appliance 16. When the appliance 16 is switched off, eliminating the demand for the gas 12, the flow detector 22 detects the stoppage of the flow and initiates a signal creating an input XI into the PLC 26. When the PLC 26 : receives the input Xl the output Yl is cancelled thus causing the valve 20 to close, preventing further flow of gas 12 into the premises until the gas 12 is again in demand.
Reference is now made to Figure 2 which shows an other embodiment of the present invention. The system 30 of this embodiment is a comparably similar system to that shown inFigure 3 the difference being that in this embodiment the system controlling means comprises a simple circuit. Both systems however operate in essentially the same manner. An appliance 32 within a premises (not shown) is supplied by gas 34 via a pipeline 36 wherein the gas 34 only flows into
the premises when it is in demand, that is when the appliance 32 is switched on.
The system 30 is operated by a 24 V D. C. power supply 38 itself supplied by a 240 V A. C. mains supply 40. Upon switching on the appliance 32 an associated normally open switch 42 is activated which completes a circuit allowing power to flow to a valve 44 via wires 46 causing the valve 44 to open and permit gas to flow. The valve 44 is a 24 VD. C. motorised valve and is positioned out with the premises and is integrated into the pipeline 36. When the gas 34 begins to flow an electronically normally closed flow detector 48 completes an associated circuit thus keeping the valve open. When the appliance 32 is switched off the gas 34 will cease to flow which will cause the flow detector 48 to open thus breaking the circuit and causing the valve to close and so preventing the flow of gas 34 into the premises.
It should be understood that the embodiments hereinbefore described are merely exemplary of the present invention and various modifications may be made thereto without departing from the scope of the invention. For example, the system may be utilised with any fluid supply which may flow into a premises such as water or oil or the like. The system may also have application in process plants for feeding a chemical process for example with raw materials on demand. Further, any number of appliances
which utilise the fluid being supplied may be incorporated into the system. The means of supplying the fluid to an appliance within a premises may be a flexible hose like those usually associated with gas bottles and the like.
The valve and the flow detecting means may be integrated into a single unit to minimise space expenditure and reduce disruption to a fluid supply line. An integrated unit would also provide for ease of use with systems using gas bottles and the like; for example where gas is supplied to a caravan or the like from a portable gas supply. The components in the systems shown in the diagrams are connected via wires, however the system may be wire-free such that the components comprise their own local power
source and communicate via radio waves and the like. This w would enable the system to be incorporated into premises with very little disturbance to the structure.