GB2106613A - Pressure regulating valve - Google Patents

Abstract

A bellows type pressure regulating valve includes a member (15) in the shape of an inverted top hat which is downwardly inserted in the bellows (12) so as to allow the pressure-sensitive chamber (A) to have a drastically reduced capacity without sacrificing a large internal surface area of the bellows (12) thereby increasing the stroke without sacrificing the response. An orifice plate (18) is detachably secured between the outlet chamber (3) of the valve chest (1) and the pressure-sensitive chamber (A) so that one orifice plate (18) may be easily replaced by another, for differing fluids. <IMAGE>

Description

SPECIFICATION Pressure regulating valve The present invention relates to a pressure regulating valve, and more particularly to a bellows type pressure regulating valve.

Prior art bellows type pressure regulating valves have the following disadvantages: 1. Although a pressure regulating valve of this type has an advantage that the degree of opening of the valve can be easily enlarged by using the bellows having a larger number of pleats, the bellows having a larger number of pleats have the disadvantage that the capacity of a pressure-sensitive chamber defined by the bellows increases in proportion to the number of pleats of the bellows. The larger the capacity is, the less sensitive the pressure-sensitive chamber becomes to the fluctuations in the internal pressure of the inlet or outlet chamber of the valve chest. The lower sensitivity of the pressure-sensitive chamber is detrimental to the accuracy and promptness required of a pressure regulating valve.

2. It is to be desired that the internal pressure of the inlet or outlet chamber of the valve chest should be transmitted to the pressure-sensitive chamber as a static pressure. However, a fixed diameter of the orifices, by which the inlet or outlet chamber communicates with the pressure-sensitive chamber, is not always appropriate for meeting such desirableness.

Large-diameter orifices will allow a low-viscosity fluid to cause an abrupt dynamic pressure upon the internal surface of the bellows and thereby cause a severe vibration of the bellows and a valve push rod connected thereto. Small-diameter orifices will prevent a high-viscosity fluid from quickly exerting a pressure upon the internal surface of the bellows and thereby make the bellows slow in responding to a change in the fluid pressure in the inlet or outlet chamber. Thus the degree of opening of the valve will get out of proper control.

3. As shown in Fig. 7, the conventional means for adjusting the stroke of the valve puphrod 16' comprises a bell-shaped upper body 6' secured to a valve chest 1', a threaded bolt 23' received in the internally threaded central longitudinal opening provided in the upper wall of the bell-shaped upper body 6', and a spring 25' engaging at opposite ends against the lower surface of a spring bearing 24' and the upper surface of a diaphragm 28, to the lower surface of which the valve pushrod 16' is affixed. (This conventional means is described as a one incorporated in a diaphragm type pressure regulating valve for the purpose of simplifying the description.) If the lower end of the threaded bolt 23' made contact with the upper surface of the spring bearing 24' by a large contact surface area, the threaded bolt 23' and the spring bearing 24' would act as a clutch and, when the threaded bolt 23' is screwed into the interior of the bell-shaped upper body 6', the spring bearing 24' would be driven by the threaded bolt 23' and cause a twist in the spring 25'. The twisted spring 25' would cause deformation or destruction of the diaphragm 28.In order to prevent this from occurring, the above-mentioned contact surface area has to be minimized, for which purpose the lower end of the threaded bolt 23' is roundheaded so as to be received in a shallow conical recess provided in the center of the upper surface of the spring bearing 24'.

However, the combination of the roundheaded lower end of the threaded bolt 23' and the shallow conical recess in the spring bearing 24' makes the spring bearing 24' precarious and thereby makes the spring 25' susceptible to buckling.

It is an object of the present invention to obviate the above-described disadvantages.

In more concrete terms, it is the first object of the present invention to provide a pressure regulating valve which allows a pressure-sensitive chamber within the bellows to have a drastically reduced capacity without sacrificing a large internal surface area of the bellows so as to make the pressure-sensitive chamber highly sensitive to the fluctuations in the internal pressure of an inlet or outlet chamber of the valve chest.

It is the second object of the present invention to provide a pressure regulating valve in which an orifice plate is detachably secured between the inlet or outlet chamber of the valve chest and the pressure-sensitive chamber so that one orifice plate may be easily repiaced by another and thereby the diameter of the orifices may be optimized to the viscosity of the fluid.

It is the third object of the present invention to provide a pressure regulating valve in which a spring incorporated in the means for adjusting the stroke of the valve push rod is free from buckling.

With these objects in view, the present invention will become apparent from the following detailed description, which will be more clearly understood in connection with the accompanying drawings, in which Fig. lisa vertical section of an embodiment of the present invention; Fig. 2 is an exploded perspective view of the bellows and a member in the shape of an inverted top hat to be inserted in the bellows to reduce the capacity of a pressure-sensitive chamber defined by the bellows; Fig. 3 is a plan view ofthe orifice plate; Fig. 4 is a plan view of a stop ring to be used for retaining the orifice plate against displacement from its proper place; Fig. 5 is a plan view of a modified type of the stop ring; Fig. 6 is a sectional view taken along line VI-VI of Fig. 1; and Fig. 7 is a vertical section of a conventional means for adjusting the stroke of the valve push rod.

Referring now to Fig. 1, a pressure regulating valve in accordance with the present invention includes a valve chest 1 which is partitioned into an inlet chamber 2 and an outlet chamber 3 by a partition wall 4. The upper wall of the valve chest 1 has an internally threaded boss 5 integral therewith for receiving the externally threaded lower end portion of a bell-shaped upper body 6.

The partition wall 4 has an internally threaded hole for receiving an externally threaded cap 7 in such a manner that the cap 7 is made coaxial with the upper body 6. The cap 7 has a passageway 8 formed axially therethrough in the center thereof for the jow Of a fluid from the inlet chamber 2 into the outlet chamber 3. The lower brim Se of the passageway 8 serves as a valve seat on which a ball valve 9 rests. A strainer 10 serves to capture any solid matter which may be introduced into the inlet chamber 2. A spring 11 disposed in the strainer 10 u.3es the ball valve 9 into contact with the lower brim Se of the passageway 8.

Within the boss 5, the upper wall of the valve chest 1 is provided with a hole 22 by which the outlet chamber 3 communicates with the interior of the upper body 6. A radial shoulder 22a is defined in the lower part of the hole 22. An orifice plate 18 is removably received in the hole 22 and abuttingly engages the shoulder 22a. A stop ring 19 in the shape of the letter C fits in an annular groove provided in the hole 22 adjacent the orifice plate 18, retaining the orifice plate 18 against displacement from the abutting engagement with the shoulder 22a.

A modified type of the stop ring 19 shown in Fig. 5 has its both ends hooked so that the hooked ends 19a may be easily held between the thumb and the first finger.

Within the boss 5 and on the edge of the hole 22, gaskets 13 and 14 are interposed between the upper wall of the valve chest 1 and the lower end of the upper body 6. Bellows 12 are accommodated in the upper body 6 in such a manner that the lowerflange 12b of the bellows 12 is disposed between the gaskets 13 and 14. A member 15 in the shape of an inverted top hat is downwardly inserted in the bellows 12 and, together with the bellows 12 and the orifice plate 18, defines a pressure-sensitive chamber A, outside of which the interior of the upper body 6 is constantly kept at atmospheric pressure by a hole 17 provided in the side wall of the upper body 6.

Because of the unique shape of the member 15, the pressure-sensitive chamber A is allowed to have a drastically reduced capacity without sacrificing a large internal surface area of the bellows 12. The flange 15b of the member 15 is fixed to the upper flange 12e of the bellows 12 as by welding. In the alternative, the member 15 may be formed integrally with the bellows 12. The outlet chamber 3 and the pressure-sensitive chamber A communicate with each other by a plurality of orifices 20 provided in the orifice plate 18 so that the bellows 12 are adapted to be stretched out and deflated according to the internal pressure of the outlet chamber 3.

A push rod 16, the upper end of which is affixed to the bottom 1 5a of the member 15, is slidably received in a center hole 21 of the orifice plate 18 and extends coaxially within the passageway 8 so that the lower end of the push rod 16 is abuttable with the ball valve 9.

The upper portion of the interior recess of the upper body 6 is polygonal in transverse cross-section and receives a spring bearing 24, which is also polygonal in transverse cross-section so as to be complementary to the upper portion of the interior recess of the upper body 6. The spring bearing 24 is provided with an open bottom and an interior recess, the upper wall having an internally threaded central longitudinal opening therethrough for receiv ing the externally threaded lower 3r half portion of a bolt 23. The upper wall of the upper body 6 has a central longitudinal opening therethrough, which rotatably receives the nonthreaded upper half portion of the bolt 23 so as to allow the upper end of the bolt 23 to project from the upper wall of the upper body 6.A manual handle 26 is carried by the projecting portion of the bolt 23 by means of a pin 27 which extends through suitable openings in the manual handle 26 and also in a hole formed in the projecting portion of the bolt 23. A spring 25 fits over the externally threaded lower half portion of the bolt 23 and engages at opposite ends against the bottom 15a of the member 15 and the upper wall of the spring bearing 24.

In operation, a fluid such as steam or air is admitted into the inlet chamber 2. Then the manual handle 26 is turned so as to lower the spring bearing 24to such an extent that the pressure exerted by the spring 25 against the pushrod assembly 15 and 16 comes to exceed the pressure exerted by the fluid against the ball valve 9 so as to keep it closed. Such an excess of the former pressure over the latter causes the ball valve 9 to be forced down and thereby causes the fluid to flow into the outlet chamber 3. Then the fluid flows into the pressuresensitive chamber A through the orifices 20 and causes a difference between the internal pressure of the pressure-sensitive chamber A and the ambient atmospheric pressure. This differential pressure upwardly acts as a reaction against the spring 25.The degree of opening of the bail valve 9 is determined by the point where the above-mentioned reaction is counterpoised to the resiliency of the spring 25. A drop in the fluid pressure in the outlet chamber 3 causes a corresponding drop in the internal pressure of the pressure-sensitive chamber A. Consequently the bellows 12 are deflated, the ball valve 9 is forced down, and the degree of opening of the ball valve 9 increases to such an extent that an increased flow of the fluid from the inlet chamber 2 into the outlet chamber 3 causes the internal pressure of the latter to be restored to the initial levei.

A large-capacity pressure-sensitive chamber would be slow in responding to a change in the fluid pressure in the outlet chamber 3. Therefore, the degree of opening of a valve would be difficult to control in case of a bellows type pressure regulating valve provided with a large-capacity pressure-sensitive chamber. This difficulty is obviated by the pressure-sensitive chamber A of the present invention, the capacity of which is drastically reduced by the member 15 so that the degree of opening of the ball valve 9 is kept under good control because only a small quantity of the fluid moving through the orifices 20 is enough to allow the bellows 12 to quickly respond to a change in the fluid pressure in the outlet chamber 3.

If desired, the pressure-sensitive chamber A may communicate with the inlet chamber 2 so that the former may be allowed to respond to a change in the fluid pressure in the latter instead of responding to a change in the fluid pressure in the outlet chamber 3.

The member 15 in the shape of an inverted top hat serves to miniaturize the structure as a whole. In addition, the member 15 will serve to prevent the spring 25 from buckling if the inside diameter of the interior recess of the member 15 is properly decided so as to allow the member 15 to barely receive the lower end portion of the spring 25.

While a preferred embodiment of the present invention has been disclosed, it is to be understood that it has been described by way of example only, various other modifications being obvious.

Claims (5)

1. In a bellows type pressure regulating valve comprising a valve chest, an upper body provided with an open bottom and an interior recess and mounted on said valve chest, and bellows accommodated in said upper body and constituting a pressure-sensitive chamber, the improvement which comprises a member having a flange and assuming the shape of an inverted top hat and downwardly inserted in said bellows so that said flange is fixed to the upper edge of said bellows.

2. The pressure regulating valve as set forth in claim 1,furthercomprising an orifice plate removably received in a hole provided in a wall between said valve chest and said pressure-sensitive chamber, said orifice plate abuttingly engaging a radial shoulder defined in the lower part of said hole, a stop ring in the shape of the letter C fitting in an annular groove provided in said hole adjacent said orifice plate so as to retain said orifice plate against displacement from the abutting engagement with said radial shoulder.

3. The pressure regulating valve as set forth in claim 1, further comprising a spring bearing received in the upper portion of the interior recess of said upper body, said spring bearing being polygonal in transverse cross-section so as to be complementary to the likewise polygonal transverse cross-section assumed by the upper portion of the interior recess of said upper body, said spring bearing being provided with an open bottom and an interior recess, a bolt having its lower half portion externally threaded and received in an internally threaded central longitudinal opening provided in the upper wall of said spring bearing, said bolt having its nonthreaded upper half portion rotatably received in a central longitudinal opening provided in the upper wall of said upper body so as to allow the upper end of said bolt to project from the upper wall of said upper body, a means for turning said bolt secured to the projecting end of said bolt, and a spring fitting over the externally threaded lower half portion of said bolt and engaging at opposite ends against the bottom of said member and the upper wall of said spring bearing.

4. A bellows type pressure regulating valve, substantially as hereinbefore described with reference to Figures 1 to 4 and 6 of the accompanying drawings.

5. Avalve as claimed in claim 4, modified substantially as hereinbefore described with reference to Figure 5 of the accompanying drawings.