JPH01181111A - Voltage reducing valve - Google Patents

Abstract

PURPOSE:To prevent a chattering phenomenon by using two paths to lead a primary pressure fluid into a pressure room and adding a pilot valve to one of both paths and a valve performing the opening/closing actions reverse to those of said pilot valve. CONSTITUTION:A main path 75 and a secondary path 73 are led to a pilot main body 70 to supply the primary pressure fluid received from a primary pressure path 24 to an upper pressure room 20a of a piston 20. A pilot valve body 71 is set on the path 75 and a secondary valve body 74 which performs the opening/closing actions reverse to those of the body 71 is added to the path 73 respectively. If the secondary pressure of a secondary pressure path 34 rises up suddenly, the primary pressure fluid is led into the room 20a from the path 73 after the body 74 opened. Thus a sudden drop in pressure is never caused and a sudden rise of the piston 20 is avoided. Furthermore a sudden rise of the piston 20 is also avoided despite a sudden drop in the secondary pressure.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a pressure reducing valve that is attached to a pipe for steam, compressed air, etc. and maintains the pressure on the secondary side at a predetermined set pressure, and in particular, the present invention relates to a pressure reducing valve that is attached to a piping for steam, compressed air, etc. and maintains the pressure on the secondary side at a predetermined set pressure. Concerning improvements to pilot valves.

Conventional technology There is a conventional pressure reducing valve as shown in FIG.

The pressure reducing valve shown here includes a pressure reducing valve section 1 and a steam/water separator section 2.
and a drain valve section 3. The main body 10 has an entrance 12. Benguchi 1
4. 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 valve port is formed by a valve seat member 15.

The main valve body 18 is attached to the valve seat at the inlet end of the valve port 14 using the coil spring 1.
9, it is elastically biased and placed.

The piston 20 is slidably disposed within the cylinder 22, and the piston rod is brought into contact with the central protruding rod of the main valve body 1B through the valve port 14. The lower surface of the piston and the piston rod are connected by a substantially hemispherical surface. an upper space between the inlet 12 and the piston 20;
That is, a pilot valve 26 is disposed in a primary pressure passage 24 that communicates with the piston chamber. The diaphragm 28 is mounted with its outer peripheral edge sandwiched between the flanges 30,32. The space below the diaphragm 2B communicates with the outlet 16 through the secondary pressure 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 . A pressure setting 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 main body 10.

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 pressure acting on its lower surface, displacing the valve rod 36 and opening and closing the pilot valve 26. As a result, the primary side fluid pressure is introduced into the piston chamber, the piston 20 is driven, the main valve body 18 is displaced, and the fluid at the inlet 12 passes through the valve port 14 to the outlet 16.
flows to

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 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 4B, 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 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 The above-mentioned pressure reducing valve causes a significant chatter phenomenon when the set pressure (secondary pressure) is smaller than the primary pressure, that is, when the pressure reducing ratio is large. For example, the pressure reduction ratio is 10 on the primary side!
This is a case where the pressure is reduced from J/cri to secondary pressure 2 to 'j/cm<, and the main valve causes a chattering phenomenon every time it operates. This chattering phenomenon occurs when the pilot valve opens due to a drop in the pressure on the secondary side, and then repeats the process of opening to an extent greater than the pressure drop and then returning to the valve closing direction, resulting in a shooting state, which causes the piston to follow this process. 20 upper spaces 20
A sudden pressure fluctuation occurs, and the main valve body 18 also exhibits a turbulent state.According to experiments, in the pressure reducing valve shown in FIG. When the pressure is gradually lowered, the pilot valve 26 opens. At this time, if the pressure on the secondary side is atmospheric pressure, the primary fluid passes through the pilot valve 26 and suddenly flows into the upper space of the piston 20. 20a, the main valve body 18 repeatedly opens and closes rapidly, and each time it is confirmed that the piston 20 and the main valve body 18 momentarily separate and come into contact again. Due to the sudden opening of the valve, a jet of fluid toward the secondary side of the piston 20
It is thought that this is because the main valve body 18 cannot follow the rise of the piston 20 because it acts on the lower surface of the piston 20 and rapidly pushes the piston 20 upward. Re-contact is shocking, and such movement of the main valve body 18 and the piston 20 poses problems such as bending or breakage of the shaft portion 20b of the piston 20 and damage to the valve seat of the main valve body 18.

A technical object of the present invention is to provide a pressure reducing valve that does not cause chattering even when used at a high pressure reduction ratio.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is a main valve port provided between an inlet connected to the primary side and an outlet connected to the secondary side. A twisted pilot valve that opens and closes the
In a pressure reducing valve, the primary pressure fluid is introduced into the pressure chamber by the opening of the pilot valve, and the piston is provided so that the fluid is moved by the pressure to open the main valve body. Another passage for introducing fluid into the pressure chamber is provided, and a valve that operates in the opposite direction to the opening/closing operation of the pilot valve is provided in that passage.

Function In the present invention, another passage (auxiliary passage) is provided for introducing the primary side pressure fluid into the pressure chamber, and the above-mentioned pylon 1 is provided in the passage.
~Since the configuration includes a valve that operates in the opposite direction to the opening/closing operation of the valve, when the pressure reduction ratio is set high and the secondary pressure is set, the pilot valve becomes vibrating, causing the pilot valve to close suddenly and causing the piston to move rapidly. Even if an attempt is made to do so, the sub passage is in an open state at this time, so the primary side fluid pressure is introduced into the pressure chamber, and the piston does not rise suddenly. On the other hand, the pilot valve suddenly closes and tries to cause the piston to descend suddenly, but since the sub passage had been open until then and was supplying a certain amount of pressure to the pressure chamber, no sudden pressure fluctuations occurred. The piston does not drop suddenly. Therefore, the piston and the main valve body do not collide shockingly, and the chattering phenomenon disappears.

EXAMPLE An example illustrating the above-mentioned specific means will be described below. (
(See FIG. 1) Portions corresponding to FIG. 2 are given the same reference numerals as in FIG. 3, and detailed explanations of the pressure reducing valve are the same as those in the prior art section, and will therefore be omitted.

A pilot main body 70 housing the pilot valve 26 is communicated with a passage 75 and a sub passage 73 for supplying primary fluid pressure from the pilot valve 26 to the upper space 20a of the piston. Fluid passes through the passage 75 due to the opening and closing of the pilot valve body 71 and the valve seat 72. - On the other hand, the sub passage 73 is opened on the downward extension of the valve stem 36, and is opened and closed by a sub valve body 74 formed by molding the lower part of the valve stem 36. The sub-valve body 7°4 is a needle valve so that the flow rate can be finely adjusted. The valve stem 36 is urged upward by a spring 76 from below, and opens and closes against the urging force of the pressure setting spring 40. The sub-valve body 74 and the pilot valve body 7] are provided to operate in opposite directions, so that when the pilot valve body 71 is closed, the sub-valve body 74 is open, and conversely, when the pilot valve body 71 is open, the sub-valve body 74 is opened. In this case, the sub-valve body 74 operates to close the valve. Note that the amount of fluid flowing out from the sub passage 73 is such that the piston does not operate even when the sub passage 73 is fully open.

The action is as follows. Even if the secondary side pressure suddenly increases and the pilot valve body 71 suddenly closes the valve seat 72, the auxiliary valve body 74 opens at the same time, and the primary side fluid is introduced into the upper pressure chamber 20a of the piston through the auxiliary passage 73. , so there is no sudden pressure drop and the piston 20 does not rise suddenly. Conversely, even if the pilot valve suddenly closes and primary pressure fluid is introduced into the upper space 20a of the piston, the sub passage 73 has been in the open state and was supplying primary pressure fluid until then, so the upper part of the piston No sudden pressure fluctuation occurs in the space 20a, and the piston descends smoothly.

Effects of the Invention Therefore, according to the present invention, it is possible to prevent the chattering phenomenon that conventionally occurs under conditions of use where the pressure reduction ratio is large, and it is possible to perform stable pressure reduction.

This prevents wear and damage to the main valve body, piston, pilot section, piston shaft, etc., and improves durability. In addition, the stable secondary pressure does not adversely affect equipment used on the secondary side, improving productivity.

[Brief explanation of the drawing]

FIG. 1 is an enlarged 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. 12 Two ports 14: Valve port 16: Outlet 20: Piston 22 Niji cylinder 26: Pilot valve 28: Diaphragm 73: Sub-passage 74: Sub-valve body

Claims (1)

[Claims] 1. A main valve body provided between an inlet connected to the primary side and an outlet connected to the secondary side, which is provided to open and close the main valve port and has a valve-closing spring; A pilot valve is provided to open based on the pressure drop, and a primary pressure fluid is introduced into the pressure chamber when the pilot valve opens, and the main valve body is moved by the pressure to open the main valve body. In the pressure reducing valve equipped with a piston, there is provided another passage for introducing the primary side pressure fluid into the pressure chamber, and a valve is provided in the passage which operates in the opposite direction to the opening/closing operation of the pilot valve. Features a pressure reducing valve.