JPH01314315A - Relief mechanism for pressure reducing valve - Google Patents

Abstract

PURPOSE:To accurately hold a secondary side at constant set pressure without any delay by providing a 2nd communication hole which is smaller in diameter than a 1st communication hole which links a pressure space with an atmosphere and arranging a 2nd pressure driven member so that the 2nd pressure driven member is displaced in the opposite direction from the loading direction of a pressure control means. CONSTITUTION:When the secondary pressure rises caused by a leak in a valve part, the secondary pressure is accumulated in the pressure space 20 because the hole diameter of the 2nd communication hole 21 is smaller than the hole diameter of the 1st communication hole. The lower end of bellows 5 is prevented by a casing from being displaced downward, so the bellows 5 are displaced upward to cancel the loading of a coil spring 7 on a diaphragm 4 through an upper diaphragm presser 16. Consequently, the extent of the opening between a stem 12 and the secondary pressure part end 19 of the 1st communication hole is made sufficiently large to release the increased pressure of the secondary side speedily through the space 32, thereby accurately holding the secondary side at the set pressure without any delay.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pressure reducing valve that is attached to a fluid piping system for compressed air or the like to maintain fluid pressure on the secondary side at a constant set pressure, and in particular, it relates to a pressure reducing valve that is attached to a fluid piping system for compressed air or the like to maintain fluid pressure on the secondary side at a constant set pressure. Relating to a relief mechanism for releasing.

BACKGROUND ART For example, as shown in FIG. 2, a conventional pneumatic pressure reducing valve has a casing formed by a main body 101 having an inlet 90 and an outlet 91, and a bonnet member 109 containing a pressure adjustment spring 108. The main valve body 102 biased toward the valve seat 92 at 104 is disposed, and the main valve body 102 and the stem 10
3 and connect the upper end of the stem 103 to the diaphragm 10
5 is in contact with a relief valve seat 107 which is screwed together via a diaphragm receiver 106.

When setting the pressure, the spring force of the pressure adjustment spring 108 is adjusted by rotating the handle 111, and the secondary pressure acting on the lower surface of the diaphragm 105 is adjusted to balance this spring force.

When the secondary pressure increases due to wear of the sealing surface of the valve seat 92 or the main valve body 102, foreign matter gets caught, or a delay in closing the main valve body 102, the diaphragm 105 responds to the increased secondary pressure. As a result, the stem 103 is displaced toward the pressure adjustment spring 108 side, and the stem 103 is separated from the relief valve seat 107, so that the secondary side pressure is released from the casing through the relief hole 93 in the relief valve seat 107 and the relief hole 94 in the bonnet member 109. is released.

By releasing the secondary side pressure, the secondary side pressure of the pressure reducing valve is maintained at a predetermined constant pressure.

Problems to be Solved by the Invention In this case, there was a problem in that the secondary side boost pressure could not be released quickly. In other words, even if the secondary pressure rises slightly due to leakage from the valve part or a delay in closing the main valve element, the displacement on the pressure adjustment spring side of the diaphragm will be affected by the downward load caused by the pressure adjustment spring. Therefore, the opening between the stem and the relief valve seat is also very small, making it impossible to quickly release the secondary side pressure.

In addition, an elastic member such as synthetic rubber is generally used for the seal part of a pneumatic valve, but when the degree of opening is extremely small, the displacement is absorbed by the elastic region of the elastic member, so the actual opening becomes even more difficult. Degrees become trivial. The release of the secondary side pressure rise becomes a problem especially when even a slight increase in the secondary side pressure must be accurately controlled without delay.

1. Therefore, the technical problem of the present invention is to obtain a relief mechanism that can quickly release increased pressure on the secondary side of a pressure reducing valve even if it is a very small pressure.

Technical means for solving the problems The technical means of the present invention taken to solve the above-mentioned technical problems is a first pressure for detecting the secondary side pressure of a direct acting or pilot type pressure reducing valve. A responsive member, the first pressure responsive member, and the second pressure responsive member are connected via a connecting member, and a pressure space is formed by the second pressure responsive member, the valve casing, and the connecting member, and the pressure responsive member and the second pressure responsive member are connected to each other via a connecting member. A first communication hole that communicates with the next side pressure section is provided, and one end of the stem is disposed opposite to the end of the second side pressure section of the first communication hole, and the first communication hole that communicates the pressure space with the atmosphere is A second communication hole with a small diameter is provided, and a pressure adjusting means for adjusting the set pressure is connected to the first pressure responsive member through the connecting member, and the displacement of the second pressure responsive member is in the load direction of the J adjusting means. It is placed in the opposite direction.

When the working secondary side pressure increases, the first pressure responsive member is displaced to the opposite side of the stem, thereby opening the first communication hole. The secondary pressure passes through the first communication hole and accumulates in a pressure space formed by the second pressure responsive member, the valve casing, and the connecting member. The second pressure-responsive member offsets the load of the pressure adjustment means by the pressure in the pressure space, so that the degree of opening between the stem and the first communication hole becomes sufficiently large, and the secondary side rising pressure is quickly increased in the pressure space. It is then released into the atmosphere through the second communication hole.

When the pressure on the secondary side is not increased, the first communication hole is closed by the stem and the inside of the pressure space becomes equal to atmospheric pressure. Detects pressure and keeps it constant.

Effects of the invention The opening degree of the valve that releases the increased secondary side pressure is sufficiently large, and even a slight increase in the secondary side pressure can be quickly released, and the secondary side pressure can be maintained at a constant level accurately and without delay. Can be maintained at the set pressure.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1).

A main body 3 provided with an outlet 2, a holding member 6 that holds the first and second pressure responsive members 4 and 5, and a cover member 8 that accommodates a coil spring 7 as a pressure adjusting means are attached by bolts 6.
0 to form the valve casing.

A valve seat 9 is provided on the population 1 side of the main body 3, and a main valve body 10 is placed at an opposing position, biased against the valve seat 9 by a spring 11. One end of the stem 12 is inserted into the center of the main valve body 10 and engaged with the snap ring 13, and the guide hole 1 has its upper part penetrated into the main body 3.
5, and the upper end portion 14 serves as a valve body of the relief mechanism.

A diaphragm 4 is provided between the water body 3 and the holding member 6 as a first pressure responsive member for detecting fluid pressure on the secondary side. A bellows 5 as an annular second pressure-responsive member is attached to the side step 30 of the diaphragm 4 of the holding member 6 through a fixing plate 31 by welding one end and the other end to the 7-run part of the upper diaphragm retainer 16. Allocate. Diaphragm 4 and bellows 5
means upper diaphragm presser 16 and lower diaphragm presser 1.
(2) They are connected by a connecting member formed by screwing them together with 8. A pressure space 20 is formed by the bellows 5, the valve casing via the fixing plate 31, and the upper diaphragm retainer 16. The secondary pressure acts on the lower surface of the diaphragm 4 through the through hole 61 provided on the outlet 2 side of the main body 3. Lower diaphragm presser foot 1
The through hole 17 provided in the upper diaphragm presser 8, the space 32 and the through hole 33 provided in the upper diaphragm retainer 16 form a first communication hole that communicates the pressure space 20 with the secondary pressure part. The secondary pressure section end 19 of the stem 12 and the upper end 14 of the stem 12 are arranged on the same axis.

The upper diaphragm retainer 16 is provided with a second communication hole 21 that communicates between the pressure space 20 and the inside of the cover member 8 via the through hole 33 and the space 32. The diameter of the second communication hole 2-1 is smaller than that of the first communication hole.

The cover member 8 is provided with a ventilation hole 62 that communicates with the atmosphere.
Ru.

The secondary side pressure is determined by the magnitude of the pressure on the lower surface of the diaphragm 4 and the spring force of the coil spring 7, and the main valve element 10 opens and closes, causing the valve seat 9 to open and close.
The pressure on the secondary side is maintained at the set value by adjusting the opening degree. The spring force of the coil spring 7 is adjusted as appropriate by rotating the handle 35 and moving the adjusting screw 36 up and down.

When the secondary pressure increases due to leakage from the valve, etc., the diaphragm 4 overcomes the spring force of the coil spring 7 and the coil spring 7
As the secondary pressure portion end 19 of the first communication hole and the stem 12 are separated from each other by slight displacement to the side, the secondary pressure is reduced to the pressure space 2.
It reaches within 0. Since the diameter of the second communication hole 21 is smaller than the diameter of the first communication hole, secondary pressure accumulates within the pressure space 20 .

Since the lower end of the bellows 5 is prevented from being displaced downward by the casing, the bellows 5 is displaced upward and cancels the load of the coil spring 7 on the diaphragm 4 via the upper diaphragm retainer 16. By canceling out the load on the diaphragm 4, the degree of opening between the stem 12 and the secondary side pressure part @19 of the first communication hole becomes sufficiently large, and the increased secondary side pressure flows through the space 32. It is quickly released to the atmosphere and the pressure on the secondary side can be accurately maintained at the set pressure without delay.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pressure reducing valve according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional pneumatic pressure reducing valve. 1: Inlet 2: Outlet 3: Main body 4: Diaphragm 5: Bellows
7: Coil spring 8: Cover part 9: Valve seat

Claims (1)

[Claims] 1. A first pressure responsive member for detecting the secondary side pressure of the pressure reducing valve, the first pressure responsive member and the second pressure responsive member being connected via a connecting member, and the second pressure responsive member and the valve casing. A pressure space is formed by the and the connecting member, a first communication hole is provided to communicate the pressure space with the secondary pressure part, and one end of the stem is opposed to the end of the secondary pressure part of the first communication hole. a second communication hole having a smaller diameter than the first communication hole that communicates the pressure space with the atmosphere, and connects a pressure adjustment means for adjusting the set pressure to the first pressure responsive member via the connection member. , second
A relief mechanism for a pressure reducing valve arranged so that the displacement of the pressure responsive member is in the opposite direction to the load direction of the pressure regulating means.