GB2243668A

GB2243668A - Gas valve unit

Info

Publication number: GB2243668A
Application number: GB9010172A
Authority: GB
Inventors: Cheng-Sheng Hsiao
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-04
Filing date: 1990-05-04
Publication date: 1991-11-06
Also published as: GB9010172D0

Abstract

A gas valve unit comprises a first valve body 1 provided with an inlet 11 and an outlet 12, and a central recess 13 containing a steel ball 21 arranged to engage with a sealing member 24 when there is excessive gas flow. A valve rod 22 is downwardly movable against the action of return spring 27, to release the ball and also serves to communicate the recess 13, by means of a through passage 222, with a pressure gauge 3. <IMAGE>

Description

Gas Valve Unit The invention relates to a gas valve unit for connection between a gas supply and a gas appliance.

A known gas valve for use between a gas cylinder and a gas range or stove is shown in cross-section in Figure 6. The valve is designed to switch off automatically if the gas flow exceeds a certain flow.

As viewed in Figure 6, normal gas flow occurs along a generally horizontal flow passage from right to left and excessive gas flow causes a ball to move into a conical throat to block the flow passage and thereby automatically switch off the valve. An upwardly biased reset plunger having a tapered end portion is provided to reopen the valve by a downward action of the plunger which disengages the ball from the conical throat.

According to the invention there is provided a gas valve unit comprising an inlet for communication with a gas supply, an outlet for communication with a gas appliance, a gas flow passage between the inlet and outlet, a blocking member which under normal gas flow is located away from sealing means and which at a certain gas flow is urged thereby into engagement with the sealing means to block the gas flow passage, and a valve rod having resilient means acting thereon and movable counter to the force of the resilient means for disengaging the blocking member from the sealing means, the valve rod having secured thereto a pressure gauge for indicating the pressure in the gas flow passage, and the valve rod having defined therein a passage which communicates the gas flow passage with the pressure gauge.

Such a gas valve unit, in addition to its ability to switch off automatically if there is an abnormally high gas flow, has a pressure gauge which indicates the pressure in the gas flow passage. If the gas supply to the unit is switched off the gauge continues to indicate the pressure in the gas flow passage, so that if there is any leakage downstream of the unit the gauge will indicate zero pressure. Thus, any small leakage is detected, whilst any large leakage is prevented by automatic switch off of the gas valve unit.

The gas valve unit has the further advantage that the valve rod for disengaging the blocking member from the sealing means also serves to mount the pressure gauge and to communicate the gas flow passage with the pressure gauge. This multiple function leads to a compact and efficient. arrangement.

Preferably a first valve body is provided with the gas inlet and outlet and has a recess in which is located, e.g. by a screwed connection, a second valve body, the gas flow passage being defined at least partly in said recess. The recess may face upwardly and the gas flow passage may include a gas conduit slanting downwardly in the first valve body from the recess to the gas outlet. Thus the gas will generally flow upwardly into the recess and then downwardly via the gas conduit.

It is preferred for the second valve body to have a through hole through which the valve rod extends, the sealing means being of annular form and being received by a seat provided on an end portion of the second valve body, and the gas flow passage extending axially through the annular sealing means and radially outwardly past said end portion. The end portion of the second valve body may comprise a plurality of circumferentially spaced projections, for example a pair of diametrically opposed projections. Thus the gas can flow via the spaces between the projections which also serve to seat the annular sealing means. In order for the sealing means to have sufficient rigidity, particularly when engaged by the blocking member, the sealing means preferably comprises a sealing member engageable by the blocking member and supported by a metal packing or washer.

The resilient means preferably comprises a coil spring surrounding the valve rod and acting to urge a circumferential flange thereof into engagement with an abutment of the second valve body, for example in an upward direction. In a preferred arrangement the coil spring engages the pressure gauge secured to the valve rod.

In one preferred form of the invention the blocking member comprises a ball, e.g. of steel, arranged to more upwardly into engagement with the sealing means. The valve rod will preferably be movable downwardly against the resilient means to release the ball which in its released position will sit in a recess or hollow provided in the first valve body.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a gas valve unit in accordance with the present invention; Figure 2 is a schematic cross-sectional view of the gas valve unit connected upstream of a gas range; Figure 3 is a cross-sectional and enlarged view of the gas valve unit in normal use condition; Figure 4 is a cross-sectional and enlarged view of the gas valve unit in the closed condition; Figure 5 is a cross-sectional and enlarged view of the gas valve in the newly opened condition; and Figure 6 is a cross-sectional view of a known automatic gas switch-off valve.

Referring to Fig. 1. the gas valve unit comprises a first valve body 1, a second valve body 2 and a pressure gauge 3 as its main components.

The valve body 1, made of metal, is provided with an inlet opening 11 and an outlet opening 12 respectively at the right and the left side and not communicating directly with each other. The inlet opening 11 and the outlet opening 12 are arranged horizontally and each have a female thread for linking respectively with the connector of a gas tank or cylinder and the gas control of a gas range, as shown in Fig. 2. The valve body 1 is also provided with a central recess 13 the lower region of which communicates with the top of the inlet opening 11 and the upper region of which communicates with a small gas conduit 14 slanting downwardly from the upper region 13 into the outlet opening 12. The recess 13 has a female thread for screwing with the second valve body 2.

The second valve body 2 is provided with a male thread to screw into the recess 13. Before the second valve body 2 is screwed into the recess 12, a steel ball 21, together with a valve rod 22 with a metal washer 23 and an annular sealing member 24 between the ball 21 and the rod 22, are placed in the recess 13. The ball 21 drops under its own weight to sit in a locating hollow 15 at the bottom of the recess 13. The second valve body 2 is provided with two lower end projections 26, through which gas can flow into the gas conduit 14. The end projections 26 support the metal washer 23.

The second valve body 2 is formed with a hole 25 through which the valve rod 22 extends so as to be movable up and down therein. The valve rod has a threaded portion at its upper end to screw with a threaded hole 31 at the bottom of the pressure gauge 3.

A coil spring 27 surrounds the valve rod 22 and engages the pressure gauge to urge both the valve rod and pressure gauge upwardly. The valve rod has a projecting circumferential flange 221 which abuts under the spring force against a circumferential lip defining the hole 25 in the second valve body 2, and a through hole 222 for gas to flow through and into the pressure gauge 3. The pressure gauge can thus indicate the pressure of the gas coming through the hole 222 in the rod 22. Therefore, when the gas volume in the gas tank is decreasing to a small amount, this is clearly shown by the needle of the gauge 3. The gauge 3 is also provided with a round post 32 surrounded by a sealing gasket 33 in the second valve body 2.

Referring to Fig. 2, the gas switch valve unit is connected between a gas tank and a gas control of a gas range, and normal gas flow occurs in the direction indicated by the arrows, through the gas control, a tube or the like, and into the gas range.

Fig. 3 shows an enlarged cross-sectional view of a part of the gas valve unit. When the gas flows in a normal volume, it runs as shown by the arrows through the inlet opening 11, the recess 13, the metal washer 23, the annular sealing number 24, the conduit 14 and out of the outlet opening 12. Thus the recess 13 and the conduit 14 define a gas flow passage between the inlet and outlet. During normal flow, the ball 21 sits in the hollow 15, and the gas also flows through the through hole 222 in the valve rod 22 and into the gauge 3, which then indicates what the pressure in the gas tank is.

Referring to Fig. 4, if the tube between the gas range and the gas control therefor is broken, allowing the gas to leak out in abnormal volume, the ball 21 is pushed up by the large pressure of gas to block the sealing member 24 so that escape of gas from the tank can be stopped.

Now, referring to Fig. 5, if the broken tube is repaired, the gauge 3 and the valve rod 22 can be pushed downwardly against the ball 21 which then returns to its hollow 15. The gas can then flow normally.

As the gas valve unit remains sealed while the gas range is not in use, gas is present in the tube between the gas tank and the gas range so that the gauge indicates the normal pressure. However, should there be any leakage in the tube, all the gas therein would leak out so that the gauge would indicate zero pressure.

Therefore, any small leakage can be detected, and this is an important feature of the automatic switch off gas valve unit.

It is to be clearly understood that there are no particular features of the foregoing specification, or of any claims appended hereto, which are at present regarded as being essential to the performance of the present invention, and that any one or more of such features of combinations thereof may therefore be included in, added to, omitted from or deleted from any of such claims if and when amended during the prosecution of this application or in the filing or prosecution of any divisional application based thereon.

Furthermore the manner in which any of such features of the specification or claims are described or defined may be amended, broadened or otherwise modified in any manner which falls within the knowledge of a person skilled in the relevant art, for example so as to encompass, either implicitly or explicitly, equivalents or generalisations thereof.

Claims

1. A gas valve unit comprising an inlet for communication with a gas supply, an outlet for communication with a gas appliance, a gas flow passage between the inlet and outlet, a blocking member which under normal gas flow is located away from sealing means and which at a certain gas flow is urged thereby into engagement with the sealing means to block the gas flow passage, and a valve rod having resilient means acting thereon and movable counter to the force of the resilient means for disengaging the blocking member from the sealing means, the yalve rod having secured thereto a pressure gauge for indicating the pressure in the gas flow passage, and the valve rod having defined therein a passage which communicates the gas flow passage with the pressure gauge.

2. A gas valve unit as claimed in claim 1, further comprising a first valve body provided with the gas inlet and outlet and having a recess in which is located a second valve body, the gas flow passage being defined at least partly in said recess.

3. A gas valve unit as claimed in claim 2, wherein the recess faces upwardly and the gas flow passage includes a gas conduit slanting downwardly in the first valve body from the recess to the gas conduit.

4. A gas valve unit as claimed in claim 2 or 3, wherein the second valve body has a hole through which the valve rod extends, the sealing means being of annular form and being received by a seat provided on an end portion of the second valve body, and the gas flow passage extending axially through the annular sealing means and radially outwardly past said end portion.

5. A gas valve unit as claimed in claim 4, wherein the end portion of the second valve body comprises a plurality of circumferentially spaced projections.

6. A gas valve unit as claimed in claim 4 or 5, wherein the annular sealing means comprises a sealing member engageable by the blocking member and supported by a metal packing.

7. A gas valve unit as claimed in any of claims 2 to 6, wherein the resilient means comprises a coil spring surrounding the valve rod and acting to urge a circumferential flange thereof into engagement with an abutment of the second valve body.

8. A gas valve unit as claimed in any preceding claim, wherein the blocking member comprises a ball arranged to more upwardly into engagement with the sealing means.

9. A gas valve unit as claimed in any preceding claim, wherein the second valve body is screwed into the recess of the first valve body and the pressure gauge is screwed onto the valve rod.

10. A gas valve substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.