JPH01258010A - Pressure reducing valve - Google Patents

Abstract

PURPOSE:To prevent the generation of chattering by abutting a main valve body having a valve closing spring arranged between a primary side and a secondary side with low pressure upon a driving part for driving the main valve body in a valve opening direction through an elastic member. CONSTITUTION:A center projection 18a of a main valve 18 is cylindrically formed, a spring 21 is arranged in a cylinder 18b and the lower end of a rod 20b of a piston 20 is inserted into the cylinder 18b and abutted on the spring 21. A through hole 18c is perforated on the cylindrical part and the main valve 18 is arranged on the inlet of a valve seat 23 forming a valve port 14 so as to be excited by a main valve spring 19. Resin-made piston rings 25a, 25b are arranged in an annular groove formed on the side of the piston 20 and expanded from the inside to the outside by springs 29a, 29b so as to be optionally slid in the cylinder. When chuttering is not generated, the spring 21 holds a fixed compression state and transmits the displacement of the piston 20 to the main valve 18, so that response delay is not generated. At the time of generating chuttering, the sudden drop displacement of the piston 20 is adsorbed by the spring 21, the main valve 18 is not suddenly opened but is moderately opened and the chattering is removed, so that the member can be prevented from being damaged and the pressure reducing valve can stably hold its set pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a pressure reducing valve that is attached to a piping system for steam, compressed air, etc. to maintain fluid pressure on the secondary side at a constant set pressure.

<Prior Art> A conventional pressure reducing valve is as shown in FIG. 2, and consists of a pressure reducing valve section 1, a steam separator section 2, and a drain valve section 3.

The main body 10 has an entrance 12. Valve port 14. An outlet 16 is formed.

The inlet is connected to a high-pressure fluid source on the primary side, and the outlet is connected to a low-pressure region on the secondary side. The main valve 18 is disposed at the inlet side end of the valve port 14 and is elastically biased by a main valve spring 19.

The piston 20 is slidably disposed within the cylinder 22, and the piston rod 20b is brought into contact with the central protrusion 18a of the main valve 18 through the valve port 14. The lower surfaces of the screws 1 to 20 and the piston rod 20b are connected approximately semispherically, and a communication port 20C is opened to communicate the upper surface and the lower surface. Inlet 12 and piston 20
A pilot valve 26 is disposed in the upper space of the piston 20a, that is, in the primary pressure passage 24 that communicates with the piston 20a. diaphragm 2
8 is attached by sandwiching its outer peripheral edge between the flanges 30 and 32. The space below the diaphragm 28 communicates with the outlet 16 through a secondary pressure detection passage 34 . The head end surface of the valve stem 36 of the pilot valve 26 abuts against the central lower surface of the diaphragm 28 . Further, the pilot valve 26 is operated by a pilot spring 27.
is biased in the valve closing direction.

A pressure setting coil spring 40 is brought into contact with the upper surface of the diaphragm 28 via a spring seat 38. The adjustment screw 44 is screwed to the spring case 66 and attached.

By turning the adjustment screw 44 left and right, the elastic force of the pressure setting spring 40 that pushes down the diaphragm 28 changes.

Using the elastic force of the pressure setting spring 40 as a reference value, the diaphragm 28 curves in response to the secondary side pressure acting on the lower surface of the groove, displacing the valve rod 36 and opening and closing the pilot valve 26. As a result, the primary side fluid pressure or the piston W20
a, the piston 20 is driven to displace the main valve 18, and the fluid at the inlet 12 flows through the valve port 14 to the outlet 16. This automatically operates so that the valve port 14 opens when the fluid pressure on the secondary side decreases and closes when it increases.

A cylindrical partition member 46 is attached below the valve port 14,
An annular space 48 is formed between the main body 10 surrounding the annular space 48, and the upper part of the annular space 48 is passed through a cone-shaped screen 50 to the inlet 12.
The lower part communicates with the upper part of the drain valve chamber 52. Further, the upper part of the drain valve chamber 52 communicates with the valve port 14 through the central opening of the partition member 46 . A swirl vane 54 made of an inclined wall is arranged in the annular space 48.

Therefore, when the valve port 14 opens and the fluid in the inlet 12 passes through the annular space 48, its direction is bent by the swirl vanes 54 and the fluid is swirled. The liquid is shaken out to the outside, hits the surrounding inner wall of the main body, and flows down into the drain valve chamber 52, while the light gas swirls in the center and flows from the central opening of the partition member 46 to the valve port 1.
4, through which it flows away to exit 16.

A drain valve port 58 communicating with the drain port 56 is formed at the bottom of the drain valve chamber 52 . Covered with a float cover 62, a spherical valve float 60 is movably accommodated. A ventilation hole 64 is opened in the upper part of the float cover 62.

Therefore, the valve float 60 floats up and down with the water level in the drain valve chamber 52 to open and close the drain valve port 58, and automatically removes water accumulated in the drain valve chamber 52.

<Problems to be Solved by the Invention> In all existing pressure reducing valves, including the conventional pressure reducing valve having the above-mentioned configuration, a chattering phenomenon that generates significant vibration and noise is a phenomenon that cannot be eliminated. This means that even if the pressure is set at an appropriate flow rate, it will operate normally.
It occurs when the load on the secondary side decreases and the flow rate decreases, or it also occurs when the set pressure (secondary pressure) is small compared to the secondary pressure, that is, when the pressure reduction ratio is large.

The pressure reduction ratio is, for example, when the primary side pressure 1 oKyicrrt is reduced to the secondary side pressure 2 K9J / crA or less, and the movable parts such as the main valve 18 and the piston 20 (
It makes a fuss and causes a chattering phenomenon. This is because when the secondary pressure decreases and the pressure change is transmitted through the secondary pressure detection passage 34, when the pilot valve 26 opens, it opens more than the pressure drop and then moves in the valve closing direction. By repeating the return, a photographing state 8 is achieved, and in accordance with this, a rapid pressure fluctuation is generated in the piston 20a in the upper space of the piston 20, and the movement of the piston 20 is simultaneously transmitted to the main valve 18 that is in contact with the lower part, One of the causes is considered to be the vibration of the pyrower 1 to valve 26, in which the main valve 18 also exhibits a photographing state. Main valve 1B
opens and closes, causing the secondary side pressure to pulsate, and this sensing again acts on the lower surface of the diaphragm via the secondary pressure detection passage 34 to open and close the pilot valve 26.

This process is carried out at an accelerated rate, resulting in a photographic state in which no one is present.

In addition, when the main valve 18 suddenly opens, a jet of steam toward the secondary side acts on the lower surface of the piston 20, rapidly pushing the piston 20 up and colliding with its upper wall, causing the piston 20 to rise. This is thought to be because the main valve 18 is unable to follow the movement and collides with the piston 20 when it descends again. Re-contact is shocking, and such operation of the main valve 18 and piston 20 poses problems such as damage to the shaft portion 20b of the piston 20 and damage to the valve seat of the main valve 18. Damage to these members may make it impossible to set the secondary pressure or shorten the life of the pressure reducing valve.

Therefore, the technical problem of the present invention is to provide a pressure reducing valve that does not cause the chattering phenomenon.

<Technical means for solving the problem> As mentioned above, chattering occurs when the change in secondary pressure is significant (causing commotion) while it goes around the diaphragm, pilot valve, piston, and main valve.

Especially regarding the transmission of displacement from the piston to the main valve, the relationship between the input and output horns is a transient response.
During this time, there is no delay in response, so the main valve opens rapidly, causing a rapid increase in secondary pressure.

Taking this point into consideration, the technical means of the present invention taken to solve the above problems is to provide a device between an inlet connected to the primary side and an outlet connected to the secondary side, which has a lower pressure than the primary side. A main valve body having a valve-closing lever provided to open and close the main valve port and a drive unit that drives the main valve body in the valve-opening direction are brought into contact via an elastic member such as a spring. I can buy things.

<Operation> During normal operation without chattering, the piston transmits its displacement to the main valve with slow movement, so the spring placed between them is always bent to some extent and transmits the displacement of the piston to the main valve. Communicate without delay. However, once chattering occurs, the piston suddenly descends and tries to open the main valve rapidly, but the spring absorbs the displacement caused by the sudden movement of the piston by compressing it. As a result, the main valve does not open suddenly, but opens slowly after a short delay. That is, by delaying the response of the C main valve to sudden movements of the piston, the secondary pressure does not rise rapidly, stable feedback pressure is transmitted to the diaphragm, pilot valve, etc., and chattering does not occur.

<Example> An example showing a specific example of the above technical means will be described. (
(See Figure 1) This embodiment is an improved version of the piston and main valve part of a conventional pressure reducing valve. Parts corresponding to those in Figure 2 are given the same reference numerals, and a detailed explanation of the pressure reducing valve is given below. Omitted.

The central protrusion 18a of the main valve 18 is formed into a cylindrical shape, and the spring 21 is arranged inside the cylinder i 8 b. The lower end of 20b is inserted and brought into contact with the spring 21. A communication port 180 is opened in the cylindrical portion. Further, the main valve 18 is disposed on the inlet side of the valve piece member 23 forming the valve port 14 so as to be elastically biased by a main valve spring 19 . An annular groove is provided on the side surface of the piston 20, piston rings 25a and 25b made of fluororesin are arranged, and a biasing spring 29a is applied from the inside.

It is stretched outward at b and is slidably accommodated in the cylinder 22.

The action is as follows. During stable operation with no chattering, the main valve is displaced in a slow cycle due to changes in secondary pressure, the die hair flam, the pilot valve, and the piston, so the piston also slowly lags behind the main valve in its displacement. Tell without.

At this time, the spring 21 maintains a somewhat constant compressed state and transmits the displacement of the piston to the main valve, so there is no delay in response.

However, once chattering occurs, the piston 20 and the main valve 18 repeatedly rapidly rise and fall; at this time, the sudden downward displacement of the piston 20 is caused by the spring 2
1 is absorbed by further compression instantaneously and the main valve 1
8 is not immediately transmitted. In other words, since the instantaneous movement of the piston is transmitted to the main valve 18 with a delay, the main valve does not open suddenly but rather opens relatively slowly. Therefore, the secondary pressure does not rise rapidly, and from then on, a constant and unchanging feedback pressure is transmitted to the diaphragm, pilot valve, piston, and main valve accordingly, and no chattering occurs.

<Effects of the Invention> As described above, according to the present application, chattering is eliminated, so vibrations are eliminated and each member is not damaged, and the pressure reducing valve can continue to maintain the set pressure in a stable state.

Furthermore, by eliminating chattering, it becomes possible to set pressures in a low pressure range, which could not be set conventionally, and the range of use as a pressure reducing valve becomes wider.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional pressure reducing valve. 1: Pressure reducing valve part 2: Steam separator part 3: Drain valve part 10: Main body 12: Inlet 14: Valve port 16: Outlet 18: Main valve 18a: Central protrusion 18b: Inside cylinder 19: Main valve spring 20: Piston 20b: Piston salary 21: Spring

Claims (1)

[Claims] 1. A main valve body with a valve-closing spring installed to open and close the main valve port, which is provided between an inlet connected to the primary side and an outlet connected to the secondary side, which has a lower pressure than the primary side. A pressure reducing valve, characterized in that: and a driving part that drives the main valve body in the valve opening direction are brought into contact with each other via an elastic member such as a spring.