JPH0454498Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a pressure reducing valve that is attached to steam or compressed air piping to reduce the pressure on the secondary side by a predetermined amount compared to the primary side and maintain a constant pressure. , relates to a pilot valve part of a pilot type pressure reducing valve.

The main valve of a pilot type pressure reducing valve is operated by displacing the piston by placing the pilot valve in a passage that communicates between the primary side and the space above the piston, and controlling the amount of fluid flowing from the primary side to the space above the piston with the pilot valve. be done. The valve body of the pilot valve is operated via the pilot stem by detecting the fluid pressure on the secondary side and utilizing the displacement of the diaphragm. The stem guide hole into which the pilot stem is inserted communicates with the outlet of the pilot valve and the space below the diaphragm (hereinafter referred to as the diaphragm chamber). The diaphragm chamber communicates with the secondary side through a communication hole.

Therefore, when the pilot valve opens, the primary fluid flows into the space above the piston and at the same time passes through the gap between the pilot stem and the stem guide hole.
It may flow into the diaphragm chamber. In this way, when the fluid on the primary side leaks and flows into the diaphragm chamber, the pressure in the diaphragm chamber, which should originally be the pressure on the secondary side, changes, and the diaphragm that operates in response to this pressure malfunctions. Therefore, it is necessary to prevent fluid from leaking from the gap between the pilot stem and the stem guide hole.

Prior Art Japanese Utility Model Publication No. 46-633 discloses that a pilot stem should be inserted into a stem guide hole in a watertight and slidable manner. Judging from the accompanying drawings, this is such that the outer diameter of the pilot stem is brought as close as possible to the inner diameter of the stem guide hole, and the gap between the two is made as small as possible.

Problems to be Solved by the Invention In the above-mentioned conventional technology, the gap between the pilot stem and the stem guide hole is simply reduced, so the sliding resistance becomes large and the pilot stem becomes unable to displace if dirt gets caught. There is a problem.

Therefore, it is possible to make the gap between the pilot stem and the stem guide hole relatively large so that they do not come into contact with each other, and to interpose a synthetic resin such as fluorinated ethylene resin with low frictional resistance in the gap. In this case, if the groove provided in the pilot stem is filled with synthetic resin, the synthetic resin will thermally expand and the sliding resistance will become abnormally large, making it less sensitive to secondary pressure.

Means for Solving the Problem The technical means of the present invention taken to solve the above problem consists of a pressure-responsive part that detects the pressure on the secondary side, a pilot valve that opens and closes the valve using the pressure-responsive part. , a pilot type pressure reducing valve which opens and closes a main valve by opening and closing the pilot valve, which comprises a pilot stem for operating the pilot valve, and a stem guide having a stem guide hole into which the pilot stem is slidably inserted, An annular groove is formed on the peripheral side of the pilot stem, a plurality of synthetic resin seal rings are arranged in the groove via an intermediate ring, and cuts are provided in the seal ring, and
Spaces are provided in the radial and axial directions of the seal ring to absorb thermal expansion.

Effect The operation of the above technical means is as follows.

A plurality of synthetic resin seal rings with cuts in an annular groove formed in the pilot stem are arranged via an intermediate ring, and spaces are provided in the radial and axial directions of the seal rings to absorb thermal expansion. Therefore, even when the seal ring thermally expands, it does not press strongly against the groove or undergo plastic deformation, so sliding resistance does not increase even at high temperatures.

When fluid pressure is applied from the pilot valve toward the diaphragm, the seal ring is pushed and displaced by the fluid pressure, and the end surface on the diaphragm side is pressed against the opposing side wall of the groove. Moreover, it is pushed outward and the outer circumferential surface is pressed against the inner circumferential surface of the stem guide hole.

Effects of the invention Even if the seal ring thermally expands, the cut and the space for absorbing the thermal expansion prevent it from pressing against the inner circumferential surface of the stem guide hole with abnormal force, which prevents sliding. There is no abnormal increase in resistance, and smooth operation is possible at all times.

Even if the seal ring contracts at low temperatures, it is pressed against the side wall of the housing groove and the inner circumferential surface of the stem guide hole by the action of fluid pressure and seals between them, so no leakage occurs.

Example An example showing a specific example of the above technical means will be described.

An inlet 2 and an outlet 3 are coaxially formed in a main body 1, and the two are communicated through a valve port 4. The upper protrusion of the main valve 5 that opens and closes the valve port 4 and the lower shaft of the piston 6 are coaxially abutted against each other.

The pilot valve section 7, which controls the pressure on the upper surface of the piston 6, consists of a stem guide 11 and a pilot stem 8. The stem guide 11 has a hole in the center that passes through it vertically, and a valve seat that protrudes in an annular shape at the bottom end of the hole. A pilot stem 8 is inserted into the hole. A horizontal hole 22 is formed in the lower part of the stem guide 11, perpendicularly intersecting with the central vertical hole.

Pilot stem 8, stem guide horizontal hole 2
The portion in contact with the upper part of the hole 2 is made to have an outer diameter smaller than the inner diameter of the central vertical hole, and an annular groove is formed in the center. A seal ring 9 having a plurality of cuts is placed above and below the intermediate ring 10 in the groove. The outer diameter of the intermediate ring 10 is the same as that of the stem guide 11.
Make it slightly smaller than the inner diameter of the central vertical hole, and attach it so that it can slide. A cap having the same diameter as the intermediate ring 10 is press-fitted into the upper part of the pilot stem 8.

In the groove of the pilot stem, a space is provided in the axial direction 12 and the radial direction 13 to absorb the thermal expansion of the seal ring.
Provided for.

The stem shaft located below the horizontal hole 22 of the stem guide is made considerably thinner than the inner diameter of the vertical hole of the stem guide, so that fluid can easily pass through the space between the stem guide and the inner peripheral surface of the vertical hole.

A pilot valve 23 is connected to a protrusion at the lower end of the pilot stem, and the pilot valve is biased from below by a spring to come into contact with the valve seat of the stem guide.

The pilot valve portion 7 is located between a passage 14 communicating with the space below the valve port 4 and a passage 15 communicating with the space above the piston 6, and is operated by a diaphragm 17 elastically biased by a pressure setting spring 16. The lower end of the pressure setting spring 16 is in contact with the upper surface of the diaphragm 17, and the upper end of the pilot valve portion 7 is in contact with the lower surface. The upper space of the diaphragm 17 communicates with the outside air through a passage 18, and the lower space communicates with the outlet 3 through a passage 19.

In the space below the valve port 4, there is a water cutter 20 which is entirely cylindrical and has a lower end that expands and a swirling blade on the outer periphery of the mid-abdomen.
Place.

The fluid entering from the inlet 2 is separated by the drain section 20, and water droplets fall downward and are discharged from the trap section 21 to the outside. The gas passes through the center of the drain section 20 and heads toward the valve port 4.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the pressure reducing valve of the present invention, and FIGS. 2 and 3 are enlarged sectional views of the main parts of FIG. 1. 1...Main body, 4...Valve port, 5...Main valve, 6...
Piston, 8...Stem, 9...Seal ring,
10...Intermediate ring, 11...Stem guide, 1
2... Stem axial clearance, 13... Stem radial clearance.

Claims (1)

[Scope of utility model registration request] A pilot valve that operates the pilot valve includes a pressure responsive part that detects the pressure on the secondary side, a pilot valve that opens and closes the valve using the pressure responsive part, and a pilot type pressure reducing valve that opens and closes the main valve by opening and closing the pilot valve. In a stem guide having a stem and a stem guide hole into which the pilot stem is slidably inserted, an annular groove is formed on the circumferential surface of the pilot stem, and a plurality of synthetic resins are inserted into the groove through an intermediate ring. A pressure reducing valve in which a seal ring made of aluminum is disposed, a cut is provided in the seal ring, and a space is provided in the radial direction and axial direction of the seal ring to absorb thermal expansion.