JPS63251816A - Preventing means for abnormal vibration of pressure reducing valve - Google Patents

Abstract

PURPOSE:To eliminate the influence applied to a pressure reducing valve by securing such a mechanism where a valve body having an orifice at its center has displacement against the energizing force of a spring set in a casing when the secondary side pressure has a sudden change and the increase value of the secondary side pressure is ejected to outside through a hole drilled through the casing to outside. CONSTITUTION:When the primary side pressure has a normal slow change, a fluid can pass freely through an orifice 88 having a diameter smaller than those of pipes set before and after the orifice 88. However, the fluid cannot pass completely through the orifice 88 in case the pressure rises up due to a sudden change of pressure caused by the water hammer of a pipe set at the secondary side. Thus, the fluid displaces a valve body 90 toward the exit side against the force of a spring 92. Then, the side face of the body 90 opens an injecting port 94 and the fluid of the high pressure is ejected into the air. As a result, an instantaneous high-pressure fluid does not flow to a lower chamber of a diaphragm 28 and therefore both the diaphragm 28 and a pilot valve can have the normal stable actions. Thus, a pressure reducing valve is not affected even though the water hammer is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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 shown in FIG. This pressure reducing valve is an external detection type in which the secondary side pressure is not detected within the pressure reducing valve main body, but from the secondary side piping located a certain distance away.

The general mechanism consists of a pressure reducing valve section 1, a steam/water separator section 2, and a drain valve section 3. Hero 12 with main body 10. Main valve port 14, outlet 16
form. The inlet 12 connects the outlet 16 to the primary high pressure fluid source.
is connected to the secondary low pressure area.

The main valve port is formed by a valve seat member. The main valve body 18 is connected to the main valve port 14
The valve seat 15 is elastically biased by a coil spring and placed at the inlet side end of the valve seat 15 forming the valve seat 15.

A piston 20 is disposed in a cylinder 22 so as to be freely openable, and a piston rod 17 is brought into contact with a central protruding rod 13 of a main valve body 18 through a main valve port 14. The lower surface of the piston and the piston rod 17 are connected by a substantially hemispherical surface. Inlet 12 and piston 2
Primary pressure passage 2 that communicates the upper space of 0 and the beating piston chamber
A pilot valve 26 is disposed at 4. The diaphragm 28 is mounted with its outer peripheral edge sandwiched between the flanges 30,32. The space below the diaphragm 28 communicates with the outlet 16 through a secondary pressure passage 34 . However, in this case, since it is an external detection type, an inner plug 72 is placed in the middle of the secondary pressure passage 34 to cut off the flow of fluid. Instead, it opens near the flange portion 32 of the pilot body 74 that accommodates the pilot valve 26, connects the introduction pipe 76, and guides the pressure on the secondary side to the lower surface of the diaphragm.

The head end surface of the valve stem 36 of the pilot valve 26 abuts against the central lower surface of the diaphragm 28 .

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 and attached to the suspension case 70.

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 bends in response to the secondary side pressure from the introduction pipe 76 acting on its lower surface, displacing the valve rod 36 and opening and closing the pilot valve 26.

As a result, the next side fluid pressure is introduced into the piston chamber, the piston 20 is driven, and the main valve body 18 is displaced.
Fluid at inlet 12 flows through valve port 14 to outlet 16.

This is because when the fluid pressure on the secondary side decreases, the valve port 14 opens.
It automatically closes when it rises.

A cylindrical partition member 46 is attached below the main valve port 14, and an annular space 48 is formed between it and the main body 10 surrounding the partition wall member 46,
The upper part of the inlet 1 is passed through a cone-shaped screen 50.
2, and 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 main 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 main 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 taken 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 around the center and heads from the central opening of the partition member 46 toward the main valve port 14, passing there. Flows away to outlet 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 Present Invention In all existing pressure reducing valves, including the pressure reducing valve mentioned above, a sudden flow occurs on the secondary side of the pressure reducing valve when steam-using equipment is started or due to a sudden opening of the valve. When this occurs, water hammer with significant imaging occurs in the secondary piping. This one-
The sudden increase in pressure caused by the turret hammer acts on the lower surface of the diaphragm of the pressure reducing valve, causing the pilot valve to close suddenly. Accordingly, the main valve port is closed and the fluid to the secondary side is stopped.
The pressure drops rapidly. The diaphragm is bent downward again by the pressure setting spring, the pilot valve opens suddenly, and the secondary pressure rises rapidly.

In this way, the water hammer that occurs at the beginning of operation induces chattering in the pressure reducing valve, which ultimately increases the water hammer.

Therefore, a technical object of the present invention is to obtain a pressure reducing valve having a structure that does not affect the pressure reducing valve in any way even if water hammer occurs in the secondary side piping.

Technical means for solving the problems The technical means of the present invention taken to solve the above problems is to apply the elastic force of a pressure setting spring to the upper surface of the diaphragm, and to apply the pressure of the secondary piping to the lower surface. By controlling the flow by opening and closing the valve port with the balance of both forces,
In a pressure reducing valve that maintains a constant pressure on the secondary side, a biasing spring is placed inside the casing in the passage that introduces the pressure on the secondary side to the lower surface of the diaphragm, and an orifice is opened on the inlet side of the spring. When the valve body contacts the valve body and moves toward the outlet side by urging the spring with the sudden pressure from the inlet, the hole provided in the side wall of the casing opens and the fluid is expelled from the hole. It is equipped with an impact valve with a mechanism that

This impact valve is applicable to both external detection type pressure reducing valves and internal detection type pressure reducing valves.

Function The above-mentioned impact valve allows fluid to pass smoothly through the orifice of the valve body due to normal pressure changes, but if there is a sudden pressure increase due to a water hammer, the fluid cannot pass through the orifice and the valve body energize the biasing spring and move to the exit side. At this time, fluid is expelled from the holes provided in the side of the casing. However, since the hole provided in the side surface of the casing is normally closed by the side surface of the valve body, no fluid flows out.

Effects of the Invention Even if water hammer occurs in the secondary piping and there is a sudden pressure change, the impact valve does not have any effect on the pressure sensing part of the pressure reducing valve, that is, the diaphragm chamber. Therefore, it operates to maintain stable secondary pressure at all times. Moreover, this prevents the water hammer from increasing and quickly settles down to the desired set pressure.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1).

Figure 1 shows the pilot body 74 of the conventional pressure reducing valve shown in Figure 2.
An impact valve 80 is attached to the connection port leading to the lower chamber of the diaphragm.

The impact valve 80 includes a valve casing 82 that is hollow and has an inlet, and a holder 84 that is hollow and has an annular space around the threaded portion 8 .
Screw together with 6. A valve body 90 with an orifice 88 is disposed in the hollow bottom of the valve casing 82, and a spring 92 is disposed on the opposite side.
is accommodated to urge the valve body 90 toward the inlet side. In the cylindrical portion of the valve casing 82, a spout 94 is opened at a portion of the cylindrical portion of the valve casing 82 that contacts the side surface of the valve body 90 while the valve body 90 is seated on the bottom portion 104. An O-ring 96 is interposed between the side surface of the valve body 90 and the portion that abuts against the circumferential wall of the valve casing 82.

A threaded portion is formed at the outlet portion of the holder 84 and is coupled to the pilot body of the pressure reducing valve. A thread is formed at the inlet of the valve casing 82 and connected to a pressure introduction pipe from the secondary side. Reference numbers 98, 100, and 106 are seal members.

A scale 102 is marked on the outer peripheral wall of the holder 84.
By rotating it relative to the valve casing 82 based on this, the force with which the spring 92 presses the valve body 90 changes.

Fluid normally passes through the orifice 88, which is narrower than the diameter of the front and rear pipes, when the pressure fluctuates slowly on the secondary side, but if there is a pressure rise due to sudden pressure fluctuations due to the water hammer in the secondary piping, The fluid cannot completely pass through the orifice 88 and overcomes the spring 92 to displace the valve body toward the outlet side. As a result, the side surface of the valve body 90 opens the spout 94 to expel the high pressure fluid to the atmosphere. Therefore, instantaneous high-pressure fluid does not flow into the chamber below the diaphragm, and the diaphragm and pilot valve can perform stable and normal operations.

The scale 102 is set on the valve body 9 depending on the magnitude of the secondary set pressure value.
This is used when adjusting the elastic force of the spring 92 that biases the spring 92. When the secondary side pressure is low, the spring 92 is set in an expanded state so that the valve body 90 opens even at a weak pressure, and when the pressure is high, the spring 92 is set in a compressed state so that the valve does not open immediately. For example, if the secondary pressure is 5Kg/crA, then 0.
If the setting is made by adding 'j/ctd (optional) to 5, when the secondary pressure exceeds 5°5/ctd (optional), the increased pressure will escape to the atmosphere.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an impact valve according to a specific embodiment of the present invention attached to a pressure reducing valve, and FIG. 2 is a sectional view of a conventional pressure reducing valve.

Claims (1)

[Claims] 1. The elastic force of the pressure setting spring is applied to the top surface of the diaphragm, and the secondary piping pressure is applied to the bottom surface, and the balance of both forces opens and closes the valve port to control the flow rate, thereby controlling the secondary pressure. In a pressure reducing valve that is designed to maintain a constant pressure, there is a valve in the middle of the passage that introduces the secondary pressure to the lower surface of the diaphragm, which overcomes the biasing force of the spring provided inside the casing when the secondary pressure fluctuates rapidly. , a method for preventing abnormal vibration of a pressure reducing valve, characterized in that a valve body with an orifice in the center is displaced, and a device is disposed to remove the increased pressure on the secondary side to the outside through a hole opened in the casing that communicates with the outside. means.