JPH0738137B2 - Pilot type pressure reducing valve - Google Patents

Description

Description: INDUSTRIAL APPLICABILITY The present invention attaches to a fluid piping system to automatically regulate the primary side fluid to the secondary side to maintain the secondary side fluid system at a predetermined low pressure. The present invention relates to a pressure reducing valve that flows while flowing, and particularly to improvement of a pilot type pressure reducing valve that controls fluid pressure acting on a main valve such as a piston valve by opening and closing a pilot valve.

2. Description of the Related Art A conventional pilot type pressure reducing valve is disclosed in, for example, Japanese Utility Model Publication No. 45-32717. This places a pilot valve between the passage leading to the primary side and the passage leading to the piston upper surface,
The pilot valve is driven by the deflection of the diaphragm, which has the elastic force of the pressure setting spring on the upper surface and the secondary pressure on the lower surface, and the fluid pressure acting on the main valve such as the piston valve is controlled by opening and closing the pilot valve. It was done.

Problems to be Solved by the Present Invention In the above, when the pilot valve cannot be completely closed due to the entrapment of foreign matter such as dust or scale, there is a problem that the pressure on the secondary side rises to the pressure on the primary side. Occurs.

Therefore, a technical problem of the present invention is to prevent an abnormal increase in the secondary pressure when the pilot valve cannot be completely closed.

Means for Solving the ProblemsTechnical means of the present invention taken to solve the above technical problems, a pilot valve is arranged between the passage leading to the primary side and the passage leading to the piston upper surface, and pressure is applied to the upper surface. A pilot type pressure reducing valve that controls the fluid pressure acting on the main valve such as the piston valve by opening and closing the pilot valve by driving the pilot valve by the deflection of the diaphragm with the elastic force of the set spring exerting secondary pressure on the lower surface. At this time, a pressure responsive valve that opens and closes the primary passage that communicates with the pilot valve is provided, and a relief hole that communicates the upper surface and the lower surface of the diaphragm is provided.The relief hole is opened and closed on the upper surface of the pilot valve. The valve allows the secondary side pressure to act in the closing direction of the pressure responsive valve.

Action The action of the above technical means is as follows. The diaphragm flexes proportionally according to the deviation between the reference value due to the pressure setting spring and the fluid pressure on the secondary side, and the pilot valve opening is maintained according to the amount of flexion while maintaining the escape hole closed on the upper surface of the pilot valve. Open and close. When the pilot valve cannot be completely closed due to foreign matter being caught, the secondary side pressure rises, the diaphragm is displaced upward, and the escape hole is opened. The pressure responsive valve is closed by the secondary pressure on the lower surface of the diaphragm, and the primary passage communicating with the pilot valve is shut off. Therefore, abnormal increase in secondary pressure can be prevented.

EFFECTS OF THE INVENTION The present invention produces the following unique effects.

It is possible to install a pressure sensor on the secondary side and close the motor-operated valve that opens and closes the primary side passage according to a command from the sensor, but in this case, it is necessary to always grasp the set pressure. In the present invention, when the secondary pressure becomes higher than the set pressure, the relief hole is automatically opened and the pressure responsive valve is closed, so that abnormal pressure increase can be prevented regardless of the set pressure.

Example An example showing a specific example of the above technical means will be described (see FIG. 1).

An inlet 2 and an outlet 3 are formed in the main body 1, and they are communicated with each other through a valve port 4. A main valve 5 that opens and closes the valve port 4 is connected to a piston 6. An annular groove is provided on the outer circumference of the piston 6 to arrange the piston ring 7. An orifice 8 that communicates the upper surface and the lower surface of the piston 6 is opened.

Introduction of pressure to the upper surface of the piston 6 is controlled by the pilot valve 9. The pilot valve 9 comprises a pilot valve seat 10 and a pilot valve body 11. The pilot valve body 11 is biased upward by a spring 12 arranged below it.

The pilot valve 9 is a primary side passage leading to a space below the valve port 4.
A diaphragm 16 located between 13 and a passage 14 communicating with the space above the piston 6 and elastically biased by a pressure setting spring 15.
Operate with. The lower end of the pressure setting spring 15 is in contact with the upper surface of the diaphragm 16 via a spring bearing 17. The upper space of the diaphragm 16 is connected to the outside air through the passage 18, and the lower space is connected to the outlet 3 through the passage 19.

An escape valve seat (21) having an escape hole (20) at the center of the diaphragm (16) is screwed to a spring bearing (17). The escape hole 20 is opened and closed on the upper surface of the pilot valve body 11 of the pilot valve 9. The escape hole 20 is connected to the pressure chamber 24 of the pressure response valve 23 via the pipe member 22.

The pressure responsive valve 23 comprises a diaphragm 25, a pressure responsive valve body 26, a pressure responsive valve port 27, a valve body receiver 28 and a spring 29. The pressure responsive valve element 26 normally opens the pressure responsive valve port 27 with a spring 29 to connect the primary side passage 13 and the pilot valve 9 to each other. Escape hole 20
When the valve is opened, the diaphragm 25 biases the pressure responsive valve body 26 against the spring 29 by the secondary pressure introduced through the pipe member 22, and the pressure responsive valve port 27 is closed.

[Brief description of drawings]

FIG. 1 is a sectional view of a pilot type pressure reducing valve according to an embodiment of the present invention. 4: Valve port, 5: Main valve 6: Piston, 9: Pilot valve 13: Primary passage, 15: Pressure setting spring 16: Diaphragm, 20: Relief hole 23: Pressure response valve

Claims (1)

[Claims] Claim: What is claimed is: 1. A pilot valve is arranged between a passage communicating with a primary side and a passage communicating with an upper surface of a piston, and the pilot valve is formed by bending a diaphragm in which an elastic force of a pressure setting spring is applied to an upper surface and a secondary pressure is applied to a lower surface. In the pilot type pressure reducing valve for controlling the fluid pressure acting on the main valve such as the piston valve by opening and closing the pilot valve, a pressure responsive valve for opening and closing the primary side passage communicating with the pilot valve is provided, and the diaphragm A pilot is provided with a relief hole that connects the upper surface and the lower surface so that the relief hole is opened and closed on the upper surface of the pilot valve, and the secondary side pressure is actuated in the valve closing direction of the pressure responsive valve by opening the relief hole. Type pressure reducing valve.