GB2550329A

GB2550329A - A positive seat regulator valve

Info

Publication number: GB2550329A
Application number: GB1608148.1A
Authority: GB
Inventors: Mellors Mark
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2016-05-10
Filing date: 2016-05-10
Publication date: 2017-11-22
Also published as: GB201608148D0

Abstract

A regulator valve with a positive seat comprises a housing and a piston 10 reciprocally retained in the housing. A valve element 11 is movable with the piston 10 in a first direction to selectively close a high pressure inlet 13, and movable in a second direction to selectively open the high pressure inlet 13. The degree of opening of the high pressure inlet determines the outlet pressure of the pilot valve. A single spring 23 biasing the pilot piston is provided along with a threaded spring adjustment member 30 which is movable in a first direction to compress the spring 23, and apply biasing force of the piston 10 in the first direction, and in the second direction to compress the spring 23 and apply biasing force on the piston in the second direction.

Description

A Positive Seat Regulator Valve

The present invention relates to a positive seat regulator valve.

Such regulators are used with a source of high pressure gas when an application requires a lower pressure of gas. The regulator valve is adjustable by a user to set the desired lower regulated pressure.

The invention has been designed for bottled gas, but can also be used for a fixed gas supply. The invention is also applicable to a pilot regulator valve as well as a main regulator valve. A pilot regulator valve can be used in conjunction with a main regulator valve. In order to set the pressure of a main regulator valve, an operator has to work against the relatively high outlet pressure. By providing a pilot regulator valve to set the regulated pressure, the force required to adjust the regulated pressure is low, due to the small area of high pressure gas that the pilot is required to be exposed to. This allows an operator to set the regulated pressure more easily. Such a pilot regulator is also useful if the regulated pressure is to be set by an electric motor using an on-board power supply as it significantly reduces the power requirement.

Unless specified otherwise below, references to a regulator valve should be taken as references both to the main regulator valve and the pilot regulator valve which will be used alongside the main regulator valve.

Regulator valves broadly fall into two categories, namely a positive seat regulator (Fig. 1) and a reverse seat regulator (Fig. 2).

The positive seat regulator of Fig. 1 has a regulator piston 1 which is attached to a valve element 2. The piston 1 is biased upwardly by a seat spring 3 and in the opposite direction by an adjustment spring 4. The adjustment spring 4 is attached to a spindle 5, the axial position of which can be adjusted by the user in order to change the biasing force on the valve element 2. The region 6 beneath the valve element 2 is exposed to the inlet pressure P1 from the high pressure gas source. Also acting on the piston 1 are atmospheric pressure P2 below the piston 1, and an outlet pressure P3 above the piston 1. The arrangement shown in Fig. 1 is a pilot regulator valve and also has pilot pressure P4 in the chamber above the valve seat 2. However, the arrangement in Fig. 1 can be modified for a normal single stage positive seat regulator, where P4 is outlet pressure, which also the same as P3 above the piston.

The force acting on the piston 1 is resultant of the four above described pressure forces together with the forces from the two springs 3, 4. By adjusting the spindle 5, the user is able to adjust the resultant pressure on the piston. This changes the pilot pressure P4 and hence the outlet pressure P3.

The reverse seat valve of Fig. 2 has a poppet valve 10 biased upwardly by a seat spring 11 in a chamber exposed to the inlet pressure PI. The poppet valve 10 is opened by piston 15 which has a downwardly depending stem 12 which engages with the poppet valve to push it downwardly. The piston 15 is biased downwardly by adjustment spring 13 adjustable by a spindle 14 as described in relation to Fig. 1 and is biased upwardly by the outlet pressure P3. Thus, the pressure on the adjustment spring 13 can be varied to change the force balance across the piston 15 thereby changing the pressure P3 required to open the poppet valve 10. This allows the user to adjust the outlet pressure P3.

The most common form of valve is the reverse seat valve of Fig. 2. However, the positive seat valve of Fig. 1 is preferred when space is at a premium as the two springs can be integrated into the chambers above and below the piston and there is no need for a separate and relatively large poppet valve 10.

The present invention aims at improving the design of the positive seat regulator valve to further reduce space and/or cost.

According to the present invention there is provided a positive seat regulator valve according to claim 1.

The present invention replaces the two springs of the prior art with a single spring. This reduces the cost of the valve as it reduces the number of component parts. It also allows the size of the valve to be reduced. Further, the use of two springs imposes extra tolerance requirements on many parts of the valve to ensure that the springs are correctly loaded.

The spring may take any form such as a leaf spring, resilient rod or the like, but is preferably a helically coiled spring surrounding a stem which projects from the piston.

The spring adjustment member may take any suitable form. For example, it may extend down inside the spring. However, preferably, the spring adjustment member surrounds the spring and has a first shoulder engaging with a first end of the spring and a second shoulder engaging with a second end of the spring.

The spring adjustment member may be movable by any suitable mechanism such as a sliding mechanism or bayonet type mechanism. However, preferably, the spring adjustment member is movable via a screw threaded engagement.

An example of a regulator valve in accordance with the present invention will now be described with reference to the accompanying drawings in which:

Fig. 1 is a schematic cross-section of a positive seat regulator valve of the prior art;

Fig. 2 is a view similar to Fig. 1 of a reverse seat regulator valve of the prior art;

Fig. 3 is a cross-section through a valve according to the present invention;

Fig. 4 is a schematic cross-section demonstrating the operating principle of the invention; Fig. 5 is a view of the upper portion of Fig. 4 in a downwardly biased configuration; and Fig. 6 is a similar view to Fig. 5 in an upwardly biased configuration.

In order to best understand the present invention. Figs. 3 and 4 should be considered in conjuction as Fig. 3 represents the physical layout of the valve while Fig. 4 is a schematic representation showing the main components and the various pressures.

The valve is contained in a housing 1 which, as shown in Fig. 3, comprises a number of components, namely a base component 2, a cap component 3, an intermediate component 4 and a valve component 5. All of these components are fixed with respect to one another and appropriate 0-ring seals 6 are provided to seal the interfaces between the various components. The various components 2 to 5 are schematically depicted as a single block in Fig. 4 and can be treated as a single component for the understanding of the operation of the valve. The various components of the housing 1 define a stepped chamber 7 with a number of different regions which will be described in greater detail below.

The main component of the valve is a piston 10 which also has a number of separate regions as described below.

The bottom of the piston 10 represents a valve element 11 which seats on a valve seat 12. The valve seat 12 surrounds an inlet port 13 which is exposed to the inlet pressure PI which is the inlet from the high pressure gas source. The lower part of the piston 10 is sealed with respect to the surrounding housing 1 by an 0-ring 14 and a control pressure outlet 15 for gas at a control pressure P4 leads from a chamber above the valve seat 12. It should be noted that, with the exception of the gas inlet port 13, none of the remaining gas paths of Fig. 4 are illustrated in Fig. 3.

Above the 0-ring seal 14 is a piston element 16 which is sealed by an 0-ring seal 17 to the housing 1 to create a lower chamber 18 which is open to atmospheric pressure P2 and an upper chamber 19 which is at regulated pressure P3. The top of the upper chamber 19 is sealed with an 0-ring 20. The piston 10 extends upwardly from the piston element 16 in the form of a spool member 21 which extend up into a spring chamber 22. In this chamber, the spool member 21 is surrounded by a helical spring 23 which is supported by a lower annular disc 25 and an upper annular disc 26. Both of these discs are retained on and slideable along the spaced member 21. The spring 23 and discs 25, 26 are held in place by a screw 27 (see Fig. 3) screwed into the top of the spool member 21.

Surrounding the upper part of the spool member 21, spring 23 and upper and lower discs 25, 26 is a cage member 28 non-rotatably mounted in the cap component 3. This is shown in Fig. 3 in two parts 28A and 28B which are rigidly connected to one another. At the top of the outer surface of the cage 28 is a screw threaded portion 29. This is threadedly attached to an adjuster element 30 (shown in Fig. 3 only) which is integral with a spindle 31 projecting out of the housing. The spindle 31 is connected to a hand wheel or lever to allow rotation of the adjuster element 30. This rotation causes the cage 28 to move up and down and the effect of this is described below.

In order to increase the force on the piston 10 in a downward direction towards the seat 12, the adjustment element 30 is rotated to move the cage downwardly. The cage 28 pushes on the upper disc 26 thereby compressing the spring between the discs as shown in Fig. 5. This compression of the spring causes it to apply a biasing force on the piston 10 urging it towards the seat 11. This increased force restricts the pressure P2 and can even close it off entirely. A small bleed hole (not shown) allows flow from chamber 18 into the upper chamber 19 allowing the pressure P4 to fall. This control pressure is the pressure which controls a main regulator (not shown) and this will have the effect of decreasing the regulated pressure P3.

For a normal single stage regulator, P4 becomes the outlet pressure and this is the same as the regulated pressure P3.

In order to apply force away from the seat, the adjustment member 30 is rotated in the opposite direction moving the cage upwardly and away from the valve seat 12. The spring 23 is now compressed between the lower disc 25 and upper disc 26 which applies a biasing force on the piston 10 away from the valve seat 12. This decreases the closing force on the piston 10 allowing the valve seat 11 to open more readily. This increases the pressure P4. This pressure is applied to a main regulator (not shown) consequently increasing the regulator outlet pressure P3 which acts on the piston element 16 to balance it and maintain the regulated pressure setting.

It can therefore be seen that the spring 23 is thereby able to both “push” and “pull” the piston 10 towards and away from the seat 12. It usually requires two springs to do this.

Claims

CLAIMS:

1. A positive seat regulator valve, the valve oomprising: a housing; a piston reoiprooally retained in the housing; a valve element movable with the piston in a first direotion to selectively olose a high pressure inlet and movable in a seoond direotion opposite to the first direction to seleotively open the high pressure inlet, whereby the degree of opening of the high pressure inlet determines the outlet pressure of the pilot valve; a spring biasing the pilot piston; and a spring adjustment member movable in a first direotion to oompress the spring and apply biasing foroe of the piston in the first direotion and in the seoond direotion to oompress the spring and apply biasing force on the piston in the seoond direotion.

2. A valve aooording to olaim 1, wherein the spring is a helioally ooiled spring surrounding a stem whioh projeots from the piston.

3. A valve aooording to olaim 1 or olaim 2, wherein the spring adjustment member surrounds the spring and has a first shoulder engaging with a first end of the spring and a seoond shoulder engaging with a seoond end of the spring.

4. A valve aooording to any one of the preoeding olaims, wherein the spring adjustment member is movable via a sorew threaded engagement.