GB2078341A - A gas pressure governor - Google Patents

Abstract

A gas pressure governor comprises a main body 1 and a cover 2 with an internal partition 5 separating and inlet 3 and outlet 4. The partition 5 is formed with an annular flange 6 mounting an annular lip seal 21. A poppet valve 7 has a head 8 and a stem 9 with an internal passageway 10. The free end of the stem is connected to a main diaphragm 11 and there is an intermediate compensating diapragm 17. The valve stem is acted on by a spring 14 of which the bias can be adjusted to control the outlet pressure. The diaphragms 11 and 17 define a main chamber 24, and an inlet chamber 25 is defined between the compensating diaphragm 17 and the seal 21 co-operating with the poppet valve head 8. In operation the inlet pressure acts on the poppet valve and forces are counter-balanced by the reaction of the compensating diaphragm on the poppet valve. Advantages in the simple construction using a port sleeve 19 and the form of poppet valve and seal are described. <IMAGE>

Description

SPECIFICATION Gas pressure governor This invention relates to gas pressure governors, particularly for reducing and controlling mains gas pressure supplies for domestic premises.

It is an object of this invention to provide a governorthat is of simple design and economic to produce whilst achieving necessary pressure control under gas flow conditions arising in service.

It is another object of this invention to provide a governor which obviates pressure build up downstream of the governor when there is no gas flow.

According to this invention we provide a gas pressure governor comprising a hollow body having an inlet and an outlet separated by a partition, a poppet valve having a head subject to inlet gas pressure and adapted to co-operate with a seating mounted in the partition to control flow through the outlet, the poppet valve stem mounting adjacent one end a main diaphragm, adjustable spring bias means acting on the poppet valve, and a compensating diaphragm mounted on the valve stem intermediate the head and the main diaphragm, the main diaphragm and the compensating diaphragm defining a main chamber in the body, and the compensating diaphragm and the partition defining an inlet chamber in the body with the poppet valve having a through passageway providing a communication between the main chamber and downstream of the outlet seating, the arrangement being such that the compensating diaphragm is subject to inlet gas flow pressure to provide compensating movement of the poppet valve for pressure variations upstream of the outlet and, on changes of pressure downstream of the outlet which act on the main diaphragm by means of flow through the passageway, so that when the pressure acting on the main diaphragm exceeds the spring bias force, the main diaphragm actuates the poppet valve to close the poppet head on the seating.

Preferably, the poppet head has a part-spherical surface for engagement with an annular resilient lip seal comprising the seating mounted in the partition.

By such an arrangement, adequate sealing of the valve is assured and is self-adjusting in the event of sideways displacements of the valve in service and manufacturing tolerances can be accomodated.

It is also preferred that the seal is mounted on the partition by one end of a port sleeve extending in the inlet chamber. The lip seal is located by an annular rib on the port sleeve which engages in a complementary groove in the lip seal which is supported on an annular face formed in the partition. Accordingly, the seal is accurately located and the lip thereof is maintained circular in service to properly engage the poppet valve head.

Conveniently, the other end of the port sleeve mounts the compensating diaphragm and the port sleeve is assembled co-axially with the poppet valve and secured in the body by an annular ring that clamps the port sleeve onto the seating trapping the seal between the end of the port sleeve and the annular face in the partition.

The port sleeve is preferably cylindrical or conical with one or more ports in the side wall. The poppet valve extends through the port sleeve co-axially.

The peripheral edge of the main diaphragm is mounted in the body by locating it between a main body part and a cover body part, the body parts being secured together by suitable fasteners with the cover being open or vented to atmosphere on the side of the main diaphragm remote from the main chamber. The cover may mount the adjustable spring bias means acting on the poppet valve.

By such an arrangement the manufacture and assembly of the governor is simplified as the seating, annular faces and other mountings are all concentric and can be machined from the open side of the main body to be closed by the cover body part.

Additionally, on assembling the governor, all assembly steps can be carried out from the open side, particularly as the poppet valve head depends through the outlet seating and the seal is located thereon by the assembly of the port sleeve in the body.

Other features of this invention will now be described with reference to an exemplary embodiment of a governor depicted in section in the accompanying drawing.

The governor comprises a main body part 1 and a cover part 2 the two parts being secured together by fasteners (not shown) to form a hollow body. The body part 1 has an inlet 3 for connection to the mains gas supply and has an outlet 4 for connection to a meter or to the domestic gas line. The inlet 3 and outlet 4 are separated by a partition 5 extending therebetween. The partition 5 has an opening therethrough and this is surrounded by an internal annular flange 6.

Mounted within the body there is a poppet valve 7 having a head 8 of hollow part-spherical shape and a stem 9 through which a passageway 10 extends. The free end of the valve stem 9 is connected to a main diaphragm 11 of which the peripheral edge is secured between the main and cover parts of the body. The centre of the main diaphragm 11 is secured to the valve stem 9 between threaded nuts and a thrust plate 12 is also secured to the stem 9 adjacent to the main diaphragm 11 between the nuts. The cover part 2 is formed with a hollow boss 13 which houses a spring 14 that acts between the thrust plate 12 and another thrust plate 15. The boss 13 and the thrust plate 15 are threaded so that the position of the thrust plate 15 can be adjusted to regulate the spring bias, and an access cap 16 closes the end of the boss 13.

The spring bias is transmitted to the poppet valve through the thrust plate 14 and would be set to control the pressure reduction required.

Intermediate the end of the valve stem 9 and the head 8, a compensating diaphragm 17 is mounted on the valve stem 9 and is located by a shoulder on the valve stem and secured against the shoulder by a threaded nut on the stem. The peripheral edge of the diaphragm 17 is secured to the body between a clamping ring 18 and a port sleeve 19. The port sleeve 19 is hollow and of substantially conical shape having a plurality of ports 20 through the side wall in communication with the inlet 3. One end of the port sleeve is received in the opening formed in the partition 5 and engages with an annular lip seal 21 that is seated on the annular flange 6. The end face of the port sleeve is formed with an annular rib 22 that engages within a complementary groove in the seal 21 to locate the lip seal 21 and to prevent movement in service.The lip of the seal 21 is arranged to provide a short inclined lip projecting towards the part-spherical face of the valve head 8 and is made of a resilient material to ensure sealing contact.

By providing such shaped head and the lip seal which would be made of resilient material, slight sideways or canting movement of the poppet valve can be accomodated whilst maintaining a good sealing engagement. Additionally, the flow path over the valve head is maintained smooth so as to avoid swirling and eddies in the gas flow The port sleeve is located in the body by the reception of the one end near the seal 21 in the opening in the partition 5, and the other end is supported in another opening in the body formed in a transverse web 23. The port sleeve 19 is sealed to the body and by the clamping ring 18 the port sleeve is secured in the body with the seal 21 trapped between the annular flange 6 and the end of the port sleeve.

The diaphragms are thin and of elastomeric material, and may comprise mouldings of rubber or other suitable material. The main body part and the cover part may be castings of suitable metal, whilst the port sleeve and the valve can be of any suitable material although metal is preferred.

The compensating diaphragm 17 and the main diaphragm 11 define a main chamber 24 in the body.

An inlet chamber 25 is defined between the compensating diaphragm 17 and the seal 21 which cooperates with the valve head 8.

In operation of the governor, the inlet pressure in the inlet chamber 25 acts on the poppet valve and forces produced are counter-balanced by the reaction ofthecompensating diaphragm 17 on the poppet valve. Such compensation prevents inlet gas pressure influencing the force balance acting on the poppet valve and main diaphragm 11. In accordance with the desired pressure reduction controlled by the spring bias force, the poppet valve is open and gas flows through the inlet chamber 25 to the outlet 4.

The main chamber 24 is maintained at the same pressure as the outlet by flow through the passageway 10 through the poppet valve so that outlet pressure can be balanced by the spring bias exerted on the valve from the spring 14. If pressure downstream of the valve decreases, the spring bias exceeds the main diaphragm force so that the valve is moved further open to increase the pressure in the outlet. In the event of the pressure downstream of the valve rising, an increase in pressure occurs in the main chamber 24 which is transmitted to the main diaphragm 11, and when the force applied by the diaphragm exceeds the spring bias, the bias is overcome to that the poppet valve is moved by the diaphragm and the valve closes.

In order to permit rapid response and movement of the main diaphragm, the cover part 2 of the body is provided with a vent 26 to atmosphere.

Following the above explanation of construction and operation of the governor, it will be appreciated that the governor is of a simple construction with only two main body parts. In the main body part, the fitting and assembly of the seal, poppet valve and port sleeve is done simply from the open side, and all machining operations on the body part can be done through that side. The closure of the body by the cover part is simple, especially as the main diaphragm can be assembled to the poppet valve stem prior to such closure. Furthermore, in the even of servicing or maintenance, the replacement of the whole poppet valve and diaphragm assembly with the port sleeve can be simply carried out once the head part is removed.

Certain modifications to the governor as just described are envisaged, for example the seal could be of slightly different design, and the means of locating it could be varied such as by providing a rib on the seal and a complementary groove in the bottom of the port sleeve. Other means for clamping or holding the port sleeve in the body could be used.

Other advantages and merits of this invention will be appreciated by those skilled in this field, and simple changes and modifications to the shape of the body are considered within the scope of this invention.

Claims (10)

1. A gas pressure governor comprising a hollow body having an inlet and an outlet separated by a partition, a poppet valve having a head subject to inlet gas pressure and adapted to co-operate with a seating mounted in the partition to control flow through the outlet, the poppet valve stem mounting adjacent one end a main diaphragm, adjustable spring bias means acting on the poppet valve, and a compensating diaphragm mounted on the valve stem intermediate the head and the main diaphragm, the main diaphragm and the compensating diaphragm defining a main chamber in the body, and the compensating diaphragm and the partition defining an inlet chamber in the body with the poppet valve having a through passageway providing a communication between the main chamber and downstream of the outlet seating, the arrangement being such that the compensating diaphragm is subject to inlet gas flow pressure to provide compensating movement of the poppet valve for pressure variations upstream of the outlet which act on the main diaphragm by means of flow through the passageway, so that when the pressure acting on the main diaphragm exceeds the spring bias fote, the main diaphragm actuates the poppet valve close the poppet head on the seating.

2. A governor according to claim 1 wherein the poppet head has a part-spherical surface for engagement with an annular lip seal comprising the seating mounted in the partition.

3. A governor according to claim 2 wherein the seal is mounted in the partition by one end of a port sleeve extending in the inlet chamber.

4. A governor according to claim 3 wherein the lip seal is located by an annular rib on the port sleeve which engages in a complementary groove in the lip seal which is supported on an annular face formed in tthe partition.

5. A governor according to claim 4 wherein the other end of the port sleeve mounts the compensating diaphragm and the port sleeve is assembled co-axially with the poppet valve and secured in the body by an annular ring that clamps the port sleeve onto the seating so trapping the seal between the end of the port sleeve and the annular face in the partition.

6. A governor according to claim 5 wherein the port sleeve is cylindrical or conical with one or more ports in the side wall.

7. A governor according to claim 6 wherein the poppet valve extends through the port sleeve and is co-axial therewith.

8. A governor according to any one of the preceding claims wherein the peripheral edge of the main diaphragm is mounted in the body by locating it between a main body part and a cover body part, the body parts being secured together with the cover being open or vented to atmosphere on the side of the main diaphragm remote from the main chamber.

9. A governor according to claim 8 wherein the cover mounts the adjustable spring bias mean acting on the poppet valve.

10. A governor for controlling gas pressure substantially as hereinbefore described with reference to the accompanying drawing.