JPH01314314A - Relief mechanism for pressure reducing valve - Google Patents

Abstract

PURPOSE:To accurately maintain 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 pressure space with an atmosphere and coupling a pressure adjusting means which adjusts the set pressure to a 1st pressure driven member through a 2nd pressure driven member. CONSTITUTION:If the secondary pressure rises owing to 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 19. A 2nd diaphragm 5 positioned on the top surface of the pressure space 20 is large in diameter and pressure reception area than a 1st diaphragm 4, so the 1st diaphragm 4 is further displaced to the opposite side of a stem 12. Then, the spring force of a coil spring 7 is canceled and the extent of the opening between the stem 12 and 1st communication hole 19 is made sufficiently large to release the increased pressure of the secondary side to the atmosphere through the pressure space. Consequently, the secondary side is accurately maintained 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 a part that is brought into contact with a relief valve seat 107 that is screwed together via a diaphragm receiver 106.

To set the pressure, rotate the handle 111 to increase the spring force of the pressure adjustment spring 108 to 1Lm, and adjust the secondary pressure acting on the lower surface of the diaphragm 105 to balance this spring force.

When the secondary pressure increases due to abrasion of the seal of the valve seat 92 or the main valve body 102, jamming of foreign objects, 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 boost pressure could not be released quickly. In other words, even if the secondary pressure rises slightly due to leakage from the valve or a delay in closing the main valve, the displacement on the pressure adjustment spring side of the diaphragm will be extremely small because it is receiving a downward load from the pressure adjustment spring. Therefore, the degree of opening between the stem and the relief valve seat is also very small, and the secondary side pressure cannot be released quickly.

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.

Therefore, a technical object of the present invention is to obtain a relief mechanism that can quickly release the increased pressure on the secondary side of a pressure reducing valve even if the pressure is minute.

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 and a second pressure responsive member having a larger diameter than the first pressure responsive member are connected via a connecting member, and a pressure space is formed by the first pressure responsive member, the second pressure responsive member, and the valve casing. , a first communication hole is provided that communicates the pressure space with the secondary pressure section, and one end of the stem is disposed to face the end of the secondary pressure section of the first communication hole, thereby communicating the pressure space with the atmosphere. A second communication hole having a smaller diameter than the first communication hole is provided, and pressure adjusting means for adjusting the set pressure via the second pressure response member is connected to the first pressure response member.

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 side pressure passes through the first communication hole and connects the first pressure responsive member and the second pressure responsive member.
It accumulates in the pressure space formed by the pressure-responsive member and the valve casing. The second pressure responsive member having a larger diameter than the first pressure responsive member due to the pressure in the pressure space further displaces the first pressure responsive member to the opposite side of the stem and offsets the load of the pressure adjusting means on the stem side. As a result, the degree of opening between the stem and the first communication hole becomes sufficiently large, and the secondary side rising pressure quickly reaches the pressure space and is released 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 relief valve formed by the first communication hole, the connecting member, the pressure space, and the second communication hole is sufficiently large, and even a slight increase in pressure on the secondary side can be quickly released. The side pressure can be maintained at a constant set pressure accurately and without delay.

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 inlet 1 and an outlet 2, a holding member 6 holding diaphragms 4 and 5 as two pressure responsive members,
A valve casing is formed by connecting a cover member 8 that accommodates a coil spring 7 as a pressure adjusting means with bolts 60.

A valve seat 9 is provided on the inlet 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 first diaphragm 4 is provided between the main body 3 and the holding member 6 to detect fluid pressure on the secondary side. Similarly, a second diaphragm 5 having a larger diameter than the first diaphragm is provided between the holding member 6 and the cover member 8. The first diaphragm 4 and the second diaphragm 5 are connected by a connecting member formed by screwing together an upper diaphragm retainer 16, an intermediate diaphragm retainer 17, and a lower diaphragm retainer 18, respectively. 1st
A pressure space 20 is formed below the coil spring 7 by the diaphragm 4, the second diaphragm 5, and the valve casing. The secondary pressure is controlled by the through hole 61 provided on the outlet 2 side of the main body 3.
It acts on the lower surface of the diaphragm 4. Through holes are provided in the intermediate diaphragm holder 17 and the lower diaphragm holder 18, respectively, to form a first communication hole 19 that communicates the pressure space 20 with the secondary pressure section. The secondary side pressure part end of the first communication hole 19 and the upper end 14 of the stem 12 are arranged on the same axis.

A second communication hole 21 is provided in the second diaphragm 5 to communicate the pressure space 20 with the inside of the cover member 8 . It is assumed that the second communication hole 21 has a smaller diameter than the first communication hole 19. The cover member 8 is provided with a hole 62 communicating with the atmosphere.

The secondary side pressure is set by opening and closing the main valve element 10 depending on the magnitude of the pressure on the lower surface of the first diaphragm 4 and the spring force of the coil spring 7, and adjusting the opening degree with the valve seat 9. value is kept.

If the secondary pressure increases due to leakage from the valve, etc., the
The diaphragm 4 overcomes the spring force of the coil spring 7 and is slightly displaced toward the second diaphragm 5 to connect the first communication hole 19 and the stem 1.
2 leaves the seat, the secondary side pressure reaches inside the pressure space 20. Since the diameter of the second communication hole 21 is smaller than the diameter of the first communication hole 19, secondary pressure accumulates within the pressure space 20. The second diaphragm 5 located on the upper surface of the pressure space 20
Since the diameter is larger than that of the first diaphragm 4 and the pressure receiving area is larger, the first diaphragm 4 is further displaced to the opposite side of the stem 12, and the spring force of the coil spring 7 is offset, thereby connecting the stem 12 and the first communication hole. To accurately maintain the pressure on the secondary side at a set pressure without delay by making the opening degree between the pressure space 19 sufficiently large and quickly releasing the increased pressure on the secondary side to the atmosphere through the pressure space 20. I can do it.

[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: First diaphragm 5: Second
Diaphragm 7: Coil spring 12: Stem
15 guide holes 16, 17, 18: connecting member 19: first communication hole 20: pressure space 21: second communication hole 61: cargo hole

Claims (1)

[Claims] 1. A first pressure responsive member for detecting the secondary side pressure of the pressure reducing valve and a second pressure responsive member having a larger diameter than the first pressure responsive member are connected via a connecting member, and the first pressure responsive member is connected via a connecting member. A pressure space is formed by the member, the second pressure responsive member, and the valve casing, a first communication hole is provided that communicates the pressure space with the secondary pressure section, and a stem is provided at the end of the secondary pressure section of the first communication hole. A pressure adjusting means for adjusting the set pressure via a second pressure responsive member, the pressure adjusting means having one end facing each other and having a second communicating hole smaller in diameter than the first communicating hole communicating the pressure space with the atmosphere. a relief mechanism for a pressure reducing valve connected to the first pressure responsive member;