REGULATOR ARRANGEMENT

Abstract: A domestic gas supply regulator includes a diaphragm actuated regulator valve (28) wherein the diaphragm (34) is operated on by pressure in the low pressure region (18) and a set point pressure in a chamber (36). Electronically controlled valves (38, 40) control the gas pressure in the chamber (36). A microprocessor (42) is used to adjust the set point pressure in the chamber (36). In a second embodiment the chamber pressure is used to counteract the forces on the valve from the high pressure region. The diaphragm actuation provides high speed response while the chamber pressure accounts for long term fluctuations.

Description: REGULATOR ARRANGEMENT BACKGROUND OF THE INVENTION The invention relates to a gas supply regulator of the type used for regulating gas supply pressure provided to a commercial or residential premises. Typical gas regulator installations are interposed between the high pressure gas supply and the gas piping of the premises, usually just upstream of the gas meter. The regulator includes a regulator valve which opens when the downstream pressure drops below a predetermined pressure and closes again when that downstream pressure is reached, thereby dropping the high, variable gas pressure of the gas supply pipe to a lower, predetermined pressure for supply to the premises. Conventional regulator arrangements include a spring-biased diaphragm exposed to the downstream gas pressure such that the diaphragm actuates closing of the valve when the force on the diaphragm due to the downstream pressure is above or equal to a threshold valve and the valve opens again when the downstream pressure drops. The spring force in this arrangement is adjustable by a thumb screw or the like, but in order to gain sufficiently accurate pressure regulation a relatively large diaphragm, for example about 15-20cm diameter, is required. Thus, the regulator unit as a whole is quite large and, in situations where an electronic gas meter is used, the regulator can be at least as large as the meter itself, making it inconvenient to provide a combined gas meter/regulator unit. A known, though not necessarily commonly known, electric regulator is the Tecno regulator from Hoerbiger-Origa Corp of Illinois, USA. which is designed for applications such as ultrasonic welding or medical equipment. This regulator operates by actuation of a piezo member which controls gas pressure in an actuating chamber continuously vented into the regulator casing. The regulator includes a diaphragm exposed on one side thereof to the pressure in the actuating chamber and on the other side to atmosphere. Upon feedback control detecting a drop in output pressure below set point, the piezo member in the Tecno regulator is energised to allow gas flow into the actuating chamber, thus increasing the gas pressure in the actuating chamber and opening the regulator valve. When output pressure exceeds set point, the piezo member closes off the gas entry to the actuating chamber, the pressure in that chamber falling due to the continuous venting. The regulator valve closes. The Tecno regulator further includes a pressure relief bypass which will relieve excessive output pressure by opening a passage from the output side of the regulator valve to atmosphere. The Tecno regulator is designed primarily for process control purposes, and has limitations which it is believed would make that regulator unsuitable for regulating energy gas pressure to commercial or residential premises, specifically, the relatively slow response time of the regulator relative to the rapid changes in downstream gas pressure which occur in domestic and commercial situations as appliances are switched on and off, and the frequency with which the Tecno regulator's piezo member would need to be energised if used for this application. The present invention aims to provide a regulator arrangement which overcomes at least some of the above disadvantages. SUMMARY OF THE INVENTION The invention provides a gas supply regulator for reducing a high gas pressure in an upstream region to a lower, regulated pressure in a downstream region, the regulator including a regulator valve, actuating means for opening and closing the regulator valve, said actuating means including diaphragm means acted upon by gas pressure in the downstream region such that the regulator valve is opened in response to gas pressure in the downstream region falling below a set point pressure and closed when set point pressure is attained, said diaphragm means further being acted upon by gas pressure in a chamber, and means for introducing gas to the chamber to adjust gas pressure in the chamber so as to adjust said set point pressure. In a first preferred form, the gas pressure in the chamber provides a force on the actuating means at least partially counteracting the force on the valve from gas pressure in the upstream region. The diaphragm means may include a pair of diaphragms - a first diaphragm situated between the chamber and the downstream region for providing said counteracting force and a second diaphragm exposed to the downstream region to actuate said opening and closing. In a second preferred form, the valve is actuated by a diaphragm operated on by the differential between pressures in the chamber and the downstream region. BRIEF DESCRIPTION OF THE DRAWINGS Further preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which: Fig. 1, is a schematic cross-section of a first embodiment; Fig. 2 is a schematic cross-section of a second embodiment; and Fig. 3 is a schematic cross-section of a third embodiment. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The regulator of Fig. 1 includes a gas inlet 12 for connection to a high, variable pressure gas supply, typically 5 to 600kPa, and an outlet 14 for connection to the gas plumbing of the premises for which the regulator is installed. The regulator may also include a filter (not shown) for removing any particles in the gas supply. The gas flow path through the regulator is divided into a high pressure upstream region 16 adjacent the inlet end and a low pressure downstream region 18 adjacent the outlet, by a divider wall comprising a longitudinal wall section 20 with respective half-section walls 22a,22b at either end thereof. The longitudinal wall section has a flow orifice 24 surrounded by a protruding valve seat 26. A valve member 28 has a valve stem 30 carrying an end plate 32 which, when the valve is closed, seals against the valve seat to close off the orifice but is spaced away from the valve seat when the valve is open. The valve member further includes an actuating diaphragm 34 exposed at one side to the gas pressure in the downstream region 18 and at its opposite side to gas pressure in a chamber 36. The chamber has an electronically controlled gas inlet valve 38, such as a silicon microvalve, communicating with the upstream region of the regulator and a gas outlet 40, preferably also an electronically controlled valve but alternatively a bleed hole, leading to the downstream region. The diaphragm 34 forms part of the inner wall of the chamber. The regulator further includes a power supply 39, a microprocessor 42 and a pressure sensor 44 and pressure relief valve 46 located in the downstream region. The microprocessor controls operation of the chamber's inlet and outlet valves 38, 40 and is adapted to receive a signal from pressure sensor 44 and an external communications link (not shown), which may be a hard wired link, or a wireless link such as a mobile telecommunications, inferred, microwave or radio link. In operation, the forces on the valve member from differential gas pressure between chamber 36 and the downstream region 18, acting on opposite sides of the diaphragm, regulate opening and closing of the regulator valve. As the pressure in the downstream region drops, this differential pressure increases and the diaphragm moves inwards into the downstream region to cause opening of the valve. When the downstream region reaches the desired pressure, the force balance on the diaphragm is sufficient to move the diaphragm and valve member outwards, closing the valve. To set the regulator output pressure, which may need to vary depending on altitude and the requirements of the gas supply authority, but typically a set value between about 0.5 - 3.5kPa, a signal coding the required valve is sent to the processor 42, which then adjusts the pressure in chamber 36 by controlling valves 38 and 40, by feedback control from pressure sensor 44, until the correct output pressure is detected. This allows accurate setting of the force on the chamber side of diaphragm 34. so that sufficient accuracy of the regulated pressure can be attained using a smaller area diaphragm than that required for the prior art spring-biased regulators. As a result, the regulator can be significantly reduced in size. Thus, the rapid response opening and closing of the diaphragm is controlled by the diaphragm 34 responsive to changes in the downstream region pressure, while longer term control of the regulated pressure is effected by control of microvalves 38, 40 to adjust the chamber pressure in response to such factors as longer term fluctuations in the gas supply pressure, which are relatively slow and infrequent. In this way. the regulator achieves not only rapid response to changes in demand but reduced power consumption as the electronic adjustment operations of the regulator are actuated less often. A further advantage is that the regulator can be used as a remote cut-off or prepayment valve, the processor receiving a signal from the gas supply authority or an attached meter or pre-payment device and opening the chamber outlet valve 40 to equalise the chamber pressure with the downstream pressure. The force on the valve end plate due to high gas pressure in the upstream region will shut the valve. Alternatively, or in addition, the diaphragm may be biased to the closed position. Upon a further signal from the supply authority or the pre-payment device, the chamber inlet valve will be opened to repressurise the chamber, calibrated as described above to give the required regulator output pressure. An alternative embodiment shown in Figure 2 has the valve seat 26 and the end plate 32 disposed in the downstream region 18. The valve stem 30 is connected via a pivot arm 33 , pivot point 39 and a diaphragm linkage 35 to the diaphragm 34. Control of the pressure in chamber 36 in response to sensor 44 adjusts the set point for opening and closing of the valve. When pressure in the downstream region drops, the closing forces on both the rear of the valve end plate 32 and diaphragm 34 are reduced, the valve opening when the downstream pressure falls below the set point. A third embodiment is shown in Figure 3. In this embodiment actuation of the valve is controlled by a spring-biased diaphragm 52 having one side exposed to the low pressure region 18 and an opposite side exposed to atmospheric pressure in the regulator housing, thus regulating the gauge pressure downstream of the regulator valve. The housing has a bleed hole 54 to atmosphere to help damp movement of the diaphragm 52. The chamber pressure in chamber 36 acts on the chamber diaphragm 34 to substantially balance the force provided by the high pressure region on the end plate 32. In this way, the actuating diaphragm 52 can be small because it does not have to overcome the force created by the high pressure region on the end plate 32. Cut-off and prepayment for this embodiment are achieved by increasing the pressure in the gas chamber 36 to directly urge the valve stem and end plate towards the valve seat to close the valve. In the present invention, the mechanical portion of the regulator, that is the diaphragm assembly, is well adapted to handle rapid changes in the downstream gas pressure whilst the electronic control of the chamber pressure provides long term accuracy of the regulated pressure. The diaphragm can therefore be far smaller than in prior art regulators that rely on a large diaphragm to achieve the required accuracy. The chamber valves 38, 40 can be small because they provide longer term control of the regulated pressure and hence do not have to cause rapid pressure changes in the chamber. This has the further advantage that the electronic portion of the regulator has low power consumption. While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims: CLAIMS 1. A gas supply regulator for reducing a high gas pressure in an upstream region to a lower, regulated pressure in a downstream region, the regulator including a regulator valve, actuating means for opening and closing the regulator valve, said actuating means including diaphragm means acted upon by gas pressure in the downstream region such that the regulator valve is opened in response to gas pressure in the downstream region falling below a set point pressure and closed when set point pressure is attained, said diaphragm means further being acted upon by gas pressure in a chamber, and means for introducing gas to the chamber to adjust gas pressure in the chamber so as to adjust said set point pressure. 2. A regulator according to claim 1 wherein said regulator further includes a processor and said chamber includes an inlet valve in fluid communication with said high pressure region and electronically controlled by said processor. 3. A regulator according to claim 2 wherein said chamber further includes an outlet valve in fluid communication with said downstream region. 4. A regulator according to claim 3 wherein said outlet valve is electronically controlled by said processor. 5. A regulator according to claim 2 further including a pressure sensor located in said downstream region, said processor controlling opening and closing of said inlet valve in response to a signal from said pressure sensor to adjust said set point pressure. 6. A regulator according to claim 1 further including means to receive a signal from a gas supply authority and to adjust the gas pressure in said chamber in response to said signal. 7. A regulator according to claim 1 wherein gas pressure in said chamber provides a force on said actuating means at least partially counteracting a force on said regulator valve from gas pressure in said upstream region. 8. A regulator according to claim 7 wherein said diaphragm means includes a first diaphragm situated between said chamber and said downstream region and providing said counteracting force and a second diaphragm exposed to said downstream region to actuate said opening and closing. 9. A regulator according to claim 8 wherein said second diaphragm is a spring biased diaphragm and is exposed to ambient pressure on a side opposite a side exposed to said downstream region. 10. A regulator according to claim 1 wherein said diaphragm means includes a diaphragm acted upon by differential pressure between said chamber and said downstream region to actuate said opening and closing in response to changes in gas pressure in said downstream region. 11. A regulator according to claim 1 wherein said regulator valve includes a valve seat closed by an end plate. 12. A regulator according to claim 11 wherein said valve seat and end plate are located in said upstream region. 13. A regulator according to claim 11 wherein said valve seat and end plate are located in said downstream region. 14. A cut off device for a gas supply including a regulator according to claim 1 and communication means for communication with a gas supply authority, said regulator further including means to close said regulator valve in response to a signal received from said gas supply authority by adjusting pressure in said chamber.

Inventors: GOSLING ALEXANDER BENNET, PEARSON IAN GORDON, SMITH ERNEST ROBERT YARWOOD, SPENCE SIMON JONATHAN, GOSLING, ALEXANDER, BENNET, PEARSON, IAN, GORDON, SMITH, ERNEST, ROBERT, YARWOOD, SPENCE, SIMON, JONATHAN
Applicants: EMAIL LTD, GOSLING ALEXANDER BENNET, PEARSON IAN GORDON, SMITH ERNEST ROBERT YARWOOD, SPENCE SIMON JONATHAN, EMAIL LIMITED, GOSLING, ALEXANDER, BENNET, PEARSON, IAN, GORDON, SMITH, ERNEST, ROBERT, YARWOOD, SPENCE, SIMON, JONATHAN
Application year: 2000
Main classification: F16K31
IPC codes: F16K31, G05D16