JPH0786781B2 - 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 a pressure reducing valve that can set a large pressure reducing ratio.

For the pressure reducing valve, the elastic force of the spring is applied to one surface of the general diaphragm to make it the reference value, and the pressure of the fluid on the secondary side (downstream side of the pressure reducing valve) is applied to the other surface to make it the reference value. The diaphragm is bent according to the deviation, and the valve body connected to the diaphragm is driven to open and close the valve port. The pressure reducing valve includes a direct acting type in which a diaphragm directly drives a main valve, and a pilot type in which a diaphragm drives a pilot valve to control fluid pressure acting on a main valve such as a piston valve.

In these pressure reducing valves, if the pressure reducing ratio is relatively small, stable pressure reducing setting can be performed with one pressure reducing valve, but if the pressure reducing ratio becomes large, chattering will occur and setting will be impossible. is there. This is because when the pressure reduction ratio is large, the secondary side quickly reaches the set pressure with a slight opening of the pilot valve or main valve, so the valve closes immediately and noise is generated by repeating this small opening / closing valve. This is because chattering that causes vibration or vibration occurs.

2. Description of the Related Art Therefore, conventionally, when setting a large pressure reducing ratio, two pressure reducing valves were used to reduce the pressure in two stages as shown in FIG. That is, the primary side 30 of the high pressure is decompressed by the first pressure reducing valve 31, and the pressure-reduced fluid is further reduced by the second pressure reducing valve 32, so that the secondary side 33 has a low pressure ratio of a large pressure reduction. To the set pressure of.

Problems to be Solved by the Invention In the above, there arises a problem that the flow rate that can be supplied to the secondary side 33 becomes small. That is, the flow rate that can be supplied to the secondary side 33 is determined by the differential pressure before and after the second pressure reducing valve 32.
Since the upstream side of 32 is decompressed by the first pressure reducing valve 31,
This is because the differential pressure across the pressure reducing valve 32 is small.

Therefore, the technical problem of the present invention is to be able to set a large pressure reduction ratio without decreasing the flow rate.

Means for Solving the ProblemsTechnical means of the present invention taken to solve the above technical problems, a pilot valve is disposed between a primary side passage leading to the primary side and a passage leading to the piston surface, The pilot type 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 that applies the secondary side pressure to the other surface by the elastic force of the pressure setting spring In the pressure reducing valve, an auxiliary pressure reducing valve is arranged in the primary side passage, and the secondary side of the auxiliary pressure reducing valve is connected to the primary side of the pilot valve.

Here, as the auxiliary pressure reducing valve, either a direct acting type or a pilot type can be used.

Action The action of the above technical means is as follows. Since the fluid reduced in pressure by the auxiliary pressure reducing valve is supplied to the pilot valve of the pilot type pressure reducing valve, the pilot valve is largely displaced and can supply this pressure reduced fluid to the upper surface of the piston. Therefore, even if the primary side and the secondary side of the pilot type pressure reducing valve have a large pressure reducing ratio, the pilot valve can be largely displaced, so that the pilot valve can be prevented from opening and closing little by little and chattering does not occur. Further, the flow rate can be increased because it is determined by the differential pressure between the primary side and the secondary side of the pilot type pressure reducing valve, which is a large pressure reducing ratio.

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

As described above, according to the present invention, a large pressure reduction ratio can be set and the flow rate can be increased.

Further, since the auxiliary pressure reducing valve only needs to be able to control the primary passage of the pilot type pressure reducing valve, it can be made small, and the pilot type pressure reducing valve itself can be made small. Therefore, a small piping space is enough.

Further, as disclosed in Japanese Patent Laid-Open No. 174113/1988, the flow rate is adjusted so that the opening area of the passage extending from the pilot valve to the upper surface of the piston changes substantially in proportion to the pressure difference between the primary side and the secondary side. With a valve, the opening area of the flow rate adjusting valve is extremely narrowed at the time of start-up when the pressure on the secondary side is atmospheric pressure, so the flow rate through the main valve becomes extremely small.
There is a problem that the startup time until the pressure on the secondary side reaches the set pressure becomes long. On the other hand, in the present invention, since the flow rate by the auxiliary pressure reducing valve does not decrease even at the time of starting as described above, the flow rate through the main valve does not become extremely small and is larger than that described in the above publication. The startup time can be shortened significantly.

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. The inlet 2 is connected to the primary side 21 and the outlet 3 is connected to the secondary side 22. 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 located between the primary passage 13 communicating with the primary side 21 and the passage 14 communicating with the space above the piston 6, and is operated by a diaphragm 16 which is elastically biased by a pressure setting spring 15. 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 auxiliary pressure reducing valve 20 is arranged in the primary side passage 13. That is,
The inlet of the auxiliary pressure reducing valve 20 is connected to the primary side 21, and the outlet thereof is connected to the inlet side of the pilot valve 9.

[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, and FIG. 2 is a piping diagram showing a conventional two-stage pressure reducing valve. 4: Valve port, 5: Main valve 6: Piston, 9: Pilot valve 13: Primary passage, 15: Pressure setting spring 16: Diaphragm, 20: Auxiliary pressure reducing valve 21: Primary side, 22: Secondary side

Claims (1)

[Claims] 1. A flexure of a diaphragm in which a pilot valve is arranged between a primary passage communicating with the primary side and a passage communicating with the upper surface of the piston, and the elastic force of a pressure setting spring is applied to one surface and the secondary pressure is applied to the other surface. In a pilot type pressure reducing valve that controls the fluid pressure acting on the main valve such as the piston valve by driving the pilot valve by opening and closing the pilot valve, an auxiliary pressure reducing valve is arranged in the primary side passage to A pilot-type pressure reducing valve in which the secondary side of the valve is connected to the primary side of the pilot valve.