JPH09222926A - Pilot valve structure for pressure reducing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure reducing valve with which a foreign matter can be prevented as much as possible from being mixed into a pilot stem and the pilot stem is surely prevented from jumping out. SOLUTION: A pilot valve 12 is formed of a pilot stem 10, a stem guide 11 for guiding the sliding of the pilot stem 10, a pilot valve port 20, and a pilot valve element 15 for opening/closing the pilot valve port 20. An upper large diameter part 10a and a lower large diameter part 10b to be slid through a sliding hole 18 of the stem guide 11 are formed at the upper and lower parts of the pilot stem 10, and a small diameter part 10c is formed between both the large diameter parts 10a and 10b. Besides, a stopper ring 19 having an outer diameter larger than that of sliding hole 18 of the stem guide 11 is fitted at the section of the pilot stem 10 positioned lower than the sliding hole 18 of the stem guide 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve which is attached to a fluid piping system for steam, compressed air, liquid or the like to maintain the fluid pressure on the outlet side of the valve, that is, the secondary side of the valve, at a constant set pressure, The present invention relates to a pressure reducing valve having a built-in pilot valve that opens and closes a main valve opening in conjunction with a pressure receiving response section.

[0002]

2. Description of the Related Art As a conventional pilot type pressure reducing valve, for example, there is one shown in Japanese Patent Laid-Open No. 62-9074. This is because the pilot valve is formed by a pilot stem that interlocks with the pressure receiving response part, a stem guide that slides and guides the pilot stem, a pilot valve opening, and a pilot valve body that opens and closes the pilot valve opening. Form the upper part to the outer diameter that slides through the sliding hole of the stem guide,
The lower part has a smaller diameter than the upper part.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
There was a problem that foreign matter such as dust easily entered between the pilot stem and the stem guide. If foreign matter is mixed into the pilot stem, the movement of the pilot stem and eventually the pilot valve body is limited, and it becomes impossible to maintain the secondary side pressure at the set value.

Further, when the pressure receiving responsive portion is removed for disassembly and inspection, there is a problem that the pilot stem vigorously pops out due to the residual pressure. It is very dangerous if the pilot stem hits your face, especially your eyes.

Therefore, an object of the present invention is to provide a pressure reducing valve capable of preventing foreign matter from entering the pilot stem as much as possible and reliably preventing the pilot stem from popping out.

[0006]

Means for Solving the Problems The means of the present invention taken to solve the above problems is to provide a main valve opening between an inlet and an outlet of a valve, and check that the outlet side pressure is lower than a set pressure. A pressure reducing valve that opens the main valve opening and maintains the outlet side pressure at the set pressure by detecting the pressure-responsive portion and opening the pilot valve.The pilot valve is a pilot stem that works in conjunction with the pressure-responsive portion. A stem guide for slidingly guiding the pilot stem, a pilot valve opening, and a pilot valve body for opening and closing the pilot valve opening,
The upper large diameter part and the lower large diameter part that slide through the sliding holes of the stem guide are formed on the upper and lower parts of the pilot stem, and
A small-diameter part is formed between both large-diameter parts, and a pressure reducing valve with a retaining ring with an outer diameter larger than the sliding hole of the stem guide is attached to the part of the pilot stem located below the sliding hole of the stem guide. It has a pilot valve structure.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION By forming an upper large-diameter portion and a lower large-diameter portion on a pilot stem and forming a small-diameter portion between both large-diameter portions, the outer periphery of the small-diameter portion and the sliding hole of the stem guide are formed. The space between them serves as a pressure reservoir. This makes it difficult for fluid or foreign matter to enter the pilot stem. In addition, the pilot stem has a retaining ring with an outer diameter larger than that of the sliding hole of the stem guide at a position located below the sliding hole of the stem guide, so that fluid and foreign matter that have passed through the pilot valve port will not be collected. Hit the retaining ring. This also makes it difficult for fluid or foreign matter to enter the pilot stem. Further, the retaining ring can surely prevent the pilot stem from protruding.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment showing a specific example of the above technical means will be described. FIG. 1 shows the entire structure of the pressure reducing valve, and FIG. 2 shows the detailed structure of the pilot valve structure of the pressure reducing valve of the present invention. FIG.
At the valve casing 1, an inlet 2 and an outlet 3 are formed,
A main valve port 5 is formed in a valve seat member 4 attached to the valve casing 1. A flat plate-shaped main valve body 6 is arranged facing the main valve opening 5 by a coil spring 17 so as to be urged in a valve closing direction, and is brought into contact with a connecting rod 8 of a piston 7 at an upper portion thereof.

A piston chamber 9 above the piston 7 is connected to a pilot valve chamber 14 via a communication passage 13. The pilot valve chamber 14 is connected to the inlet 2 via the inlet pressure communication passage 32. Then, the pilot valve 12 is arranged between the inlet pressure communication passage 32 and the communication passage 13.

As shown in detail in FIG. 2, the pilot valve 12 includes a stem guide 11, a pilot valve opening 20 formed at the lower end of the stem guide 11, and a pilot valve body 15 for opening and closing the pilot valve opening 20 from below. The pilot guide 10 includes a pilot stem 10 that slides in a slide hole 18 of the stem guide 11 and a lower end of which abuts on an upper end of a pilot valve body 15, and a retaining ring 19 attached to the pilot stem 10.
The pilot stem 10 has a stem guide 1 at the top and bottom.
It has an upper large-diameter portion 10a and a lower large-diameter portion 10b that slide in one sliding hole 18, and a small-diameter portion 10c between the large-diameter portions 10a and 10b. A retaining ring 19 having a larger outer diameter than the sliding hole 18 of the stem guide 10 is attached to the pilot stem 10 at a portion located below the sliding hole 18 of the stem guide 11.

In FIG. 1, a coil spring 16 is arranged below the pilot valve body 15. The upper end of the pilot stem 10 is in contact with the central portion of the lower surface of the diaphragm 21, which serves as a pressure receiving responsive portion. As the diaphragm 21 moves up and down, the pilot stem 10 is also displaced up and down, and the pilot valve body 15
Is displaced up and down to open and close the pilot valve port 20.
The pressure on the outlet 3 side acts on the lower surface chamber 30 of the diaphragm 21 by the outlet pressure communication passage 31. A coil spring 23 for pressure setting is arranged on the upper surface of the diaphragm 21 via a diaphragm retainer 22. A pressure adjusting screw 24 is attached to the upper end of the coil spring 23 via a steel ball 25.

The operation of the pressure reducing valve is as follows.
When the pressure on the outlet 3 side becomes lower than the pressure set by the coil spring 23, the pilot valve body 15 is opened by the spring force of the coil spring 23 via the diaphragm 21 and the pilot stem 10, and the high pressure fluid on the inlet 2 side communicates. 32,1
It acts on the upper surface of the piston 7 through 3 and the piston 7 is displaced downward. The main valve body 6 is opened by the displacement of the piston 7 and the high pressure fluid on the inlet 2 side is replenished to the outlet 3 side, whereby the pressure on the outlet 3 side rises to the set pressure. When the set pressure is reached, the load that pushes the diaphragm 21 upward and the load that the coil spring 23 pushes down balance, the pilot valve body 15 closes, and the main valve body 6 also closes.

When the pilot valve body 15 opens, the fluid on the inlet 2 side also flows into the pilot valve chamber 14 via the pilot valve opening 20. However, in the present invention, this fluid is the small diameter portion 1 provided in the pilot stem 10.
0c and the retaining ring 19 prevent the inflow to the pilot stem 10 side as much as possible. Further, when the operation of the pressure reducing valve is stopped for disassembly and inspection and the diaphragm 21 is removed, the pilot stem 10 tends to pop out vigorously due to the residual pressure in the pilot valve chamber 14. However, in the present invention, the snap ring 19 provided on the pilot stem 10 can reliably prevent the pilot stem 10 from protruding.

[0014]

As described above, according to the present invention, it is possible to provide a pilot valve structure of a pressure reducing valve which makes it difficult for fluid or foreign matter to enter the pilot stem, and which can surely prevent the pilot stem from popping out.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing an embodiment of a pressure reducing valve of the present invention.

FIG. 2 is a sectional view of an essential part showing an embodiment of the pilot valve structure of the pressure reducing valve of the present invention.

[Explanation of symbols]

 2 inlet 3 outlet 5 main valve body 6 main valve body 7 piston 10 pilot stem 10a pilot stem upper large diameter portion 10b pilot stem lower large diameter portion 10c pilot stem small diameter portion 11 stem guide 12 pilot valve 14 pilot valve chamber 15 Pilot valve body 19 Retaining ring 20 Pilot valve opening 21 Diaphragm

Claims (1)

[Claims] 1. A main valve opening is provided by providing a main valve opening between an inlet and an outlet of the valve, and opening a pilot valve when a pressure receiving responsive section detects that the pressure on the outlet side has dropped below a set pressure. Is a pressure reducing valve that maintains the outlet side pressure at the set pressure by opening the pilot valve, the pilot valve that interlocks with the pressure receiving response part, the stem guide that slides and guides the pilot stem, the pilot valve opening, and the pilot valve. With a pilot valve body that opens and closes the valve opening, an upper large diameter portion and a lower large diameter portion that slide in the sliding holes of the stem guide are formed on the upper and lower portions of the pilot stem, and both large diameter portions are formed. A small diameter part is formed between the two, and a retaining ring with an outer diameter larger than the sliding hole of the stem guide is attached to the part of the pilot stem located below the sliding hole of the stem guide. valve Pilot valve structure.