JPH01128105A - Pressure reducing valve - Google Patents

Abstract

PURPOSE:To avoid the increase of the flowing speed of a liquid at a section between a 2nd valve seat part and a main valve body in case the distance between a 1st valve seat part and the main valve body is decreased by forming a stepped 2nd main valve body part in a body with the main valve body part at the upper part of this valve body after defining the plane part of the main valve body set at the inlet side as a 1st main valve body and then setting the 1st and 2nd valve seat parts in the places of the valve seat members opposite to both main valve bodies. CONSTITUTION:The plane part of a main valve body 118 of a flat plate type set at the inlet side of a valve port 114 of a pressure reducing valve is defined as the 1st main valve body part 1. Then the stepped 2nd main valve body part 2 is provided in a body with the part 1 at the upper part of the part 1. Then the 2nd and 1st valve seat parts 4 and 6 are formed in the places of valve seat members 3 and 5 opposite to both parts 1 and 2. The part 6 is energized toward the part 1 by means of a countersunk spring 7 serving as an elastic member so that the distance L between the parts 6 and 1 is reduced less than the distance H between the parts 4 and 2 by the degree of displacement of the spring 7. Thus it is possible to avoid such a case where the fluid is reduced with only the degree of displacement of the spring 7 kept as it is in case the distance L is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a main valve structure of 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.

BACKGROUND OF THE INVENTION Conventionally, as shown in FIG.
8 is brought into contact with the valve seat, a main valve shaft 165 is formed coaxially with the main valve body 118 and the main valve shaft 165 is inserted into the main valve shaft insertion hole 166 provided at the center of the cylindrical partition member 146 with a spring 167 interposed therebetween. The structure was

Its operation will be explained below.

The pressure reducing valve shown here consists of a pressure reducing valve section 101, a steam separator section '10.2, and a drain valve section '103.

The main body 110 has an inlet 112. Valve port 114. An outlet 116 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.

The main valve body 118 is placed on the valve seat at the inlet side end of the valve port 114 and is elastically biased by a coil spring.

A piston 120 is movably disposed within the cylinder 122, and the piston rod is brought into contact with the central protruding rod of the main valve body 118 through the valve port 114. Bottom surface of the piston and piston rod 1
2 are connected approximately on a hemispherical surface. Inlet 112 and piston 1
A pilot valve 126 is disposed in a primary pressure passage 124 that communicates with the upper space of 20, that is, the piston chamber. The diaphragm 128 is attached with its outer peripheral edge sandwiched between the flanges 130 and 132. The space below the diaphragm 128 communicates with the outlet 116 through a secondary pressure passage 134 .

The head end surface of the valve stem 136 of the pilot valve 126 abuts against the central lower surface of the diaphragm 128 .

A pressure setting coil spring 140 is brought into contact with the upper surface of the diaphragm 128 via a spring seat 138. An adjustment screw 144 is threadedly attached to the main body 110.

Turning the adjustment screw 144 left and right changes the elastic force of the pressure setting spring 140 that pushes down the diaphragm 128. Using the elastic force of the pressure setting spring 140 as a reference value, the diaphragm 128 curves in response to the secondary pressure acting on its lower surface, displacing the valve rod 136 and opening and closing the pilot valve 126.

As a result, downstream fluid pressure is introduced into the piston chamber, driving the piston 120 and displacing the main valve body 118, causing the fluid at the inlet 112 to pass through the valve port 114 to the outlet 116.
flows to This is because when the fluid pressure on the secondary side decreases, the valve port 1
14 opens and automatically operates to close when raised.

A cylindrical partition member 146 is attached below the valve port 114 to form an annular space 148 between it and the main body 110 surrounding it, the upper part of which communicates with the inlet 112 through a cone-shaped screen 150, and the lower part of which is connected to a drain valve. It communicates with the upper part of chamber 152. Further, the upper part of the drain valve chamber 152 is connected to the partition wall member 14.
6 communicates with the valve port 114 through the central opening. A swirl vane 154 made of an inclined wall is arranged in the annular space 148.

Therefore, when the fluid at the inlet 112 opens the valve port 114 and passes through the annular space 148, its direction is bent by the swirl vanes 154 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 152.
The light gas swirls through the center and is directed from the central opening of the septum member 146 to the valve port 114 through which it flows away to the outlet 116.

A drain valve port 158 communicating with the drain port 156 is formed at the bottom of the drain valve chamber 152 . It is covered with a float cover 162 to accommodate a spherical valve float 160 in a freely displaceable manner. A ventilation hole 164 is opened in the upper part of the float cover 162.

Therefore, the valve float 160 floats up and down with the water level in the drain valve chamber 152 to open and close the drain valve port 158, and the drain valve chamber 15
Automatically removes liquid that accumulates in 2.

Problems to be Solved by the Invention In the above-mentioned valve, there is a problem in that erosion damage occurs in the contact portion of the main valve body or the valve seat, resulting in valve leakage when the valve is closed. In other words, the contact area between the flat main valve body and the valve seat is flat, and when the opening degree of the main valve is small, the contact area between the main valve body and the valve seat is in a constricted state. The flow velocity of the flowing fluid becomes extremely high, causing erosion damage. Particularly in pressure reducing valves, high-temperature, high-pressure steam is often used as the fluid, further accelerating erosion damage.

A technical object of the present invention is to prevent erosion damage by suppressing the flow rate of fluid at the closing portion of the main valve body.

Means for Solving the Problems The technical means of the invention taken to solve the above problems is to use the flat part of the flat main valve body disposed on the inlet side of the valve port as the first main valve body, A stepped second main valve body part is integrally provided on the upper part of the first main valve body part, and a first valve seat part is provided at each valve seat member location facing the first main valve body part and the second main valve body part. and a second valve seat, the first valve seat is biased toward the first main valve body by an elastic member, and the distance between the first valve seat and the first main valve body is The distance between the second valve seat portion and the second main valve body portion is smaller by the amount of displacement of the elastic member.

action The operation of the above technical means is as follows.

The distance between the first valve seat part and the first main valve body part is the same as that between the second valve seat part and the second main valve body part.
Since the distance Jζ of the main valve body is small by the amount of displacement of the elastic member, when the main valve body moves toward the valve seat member in an attempt to close the valve, the first valve seat and the first main valve body Even if the divisions are narrowed down,
There is still a large distance between the second valve seat part and the second main valve body part, which corresponds to the amount of displacement of the elastic member.
It is not constricted like the main valve body. Furthermore, even when the main valve body moves toward the valve seat member and the first valve seat portion and the first main valve body portion come into contact, the gap between the second valve seat portion and the second main valve body portion is elastic. The valve is operated for the amount of displacement of the member. Then, the first valve seat and the first main valve body remain in contact with each other until the second valve seat and the second main valve body come into contact and the valve is reliably closed, and the elastic member is bent and displaced. At this time, the valve does not necessarily need to be closed reliably between the first valve seat and the first main valve body.

Effect of the invention The present invention produces the following unique effects.

Even if the space between the first valve seat and the first main valve body is narrowed, there is still a distance between the second valve seat and the second main valve body, so the fluid flow rate does not increase. , no erosion damage will occur. If the second valve seat and the second main valve body try to get closer together, the fluid flow will almost disappear due to contact between the first valve seat and the first main valve body, and no erosion damage will occur. do not. There is a second valve between the main valve body and the valve seat member.
The contact between the valve seat and the second main valve body ensures that the valve is closed.

EXAMPLE An example showing a specific example of the above technical means will be described below. (See FIG. 1) The parts corresponding to FIG. 2 are given the same numbers as in FIG. 2, and the detailed description of the pressure reducing valve is the same as that in the prior art section and will be omitted.

A main valve body 118 is arranged on the inlet side of the valve port 114.

The main valve body 118 has two flat parts, one of which is a first main valve body part 1 and the other part is a second main valve body part 2. The upper end of the main valve body 118 is in contact with the piston rod 12. The lower part of the main valve body 118 forms a main valve shaft 165 and is urged toward the valve seat by a spring 167. The second valve seat portion 4 is integrally formed with the valve seat member 3 screwed onto the main body 110. Coaxially with the second valve seat part 4,
A first valve seat portion 6 is formed by arranging an annular first valve seat member 5 having an L-shaped cross section. A disc spring 7 as an elastic member is attached between the first valve seat member 5 and the valve seat member 3 so that the main valve shaft 165 can be freely displaced in the axial direction. The upper part of the first valve seat member 5 is an annular piston 8
, and slidably move up and down the inner circumferential portion 9 of the valve seat member 3. The distance between the first valve seat part 6 and the first main valve body part 1 is only the amount of axial displacement of the disc spring 7 from the distance H between the second valve seat part 4 and the second main valve body part 2. Set it so that it is small.

Even if L between the first valve seat part 6 and the first main valve body part 1 is narrowed, H between the second valve seat part 4 and the second main valve body part 2 is Since a distance corresponding to the amount of displacement is left, the fluid is not restricted and erosion damage can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of the main valve portion of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. 1: First main valve body part 2: Second main valve body part 3: Valve seat member 4: Second valve seat part 5: First valve seat member 6:
1st valve seat part -〇 - 7: m spring 12: piston rod 110: main body
112: Inlet 114: Valve port 116: Outlet

Claims (1)

[Claims] 1. The flat part of the flat main valve body disposed on the inlet side of the valve port is the first main valve body part, and the step-shaped second main valve body part is integrally provided on the upper part of the first main valve body part. , a first valve seat portion and a second valve seat portion are arranged at the valve seat member locations facing the first main valve body portion and the second main valve body portion, respectively, and the first valve seat portion is made of an elastic member and the first valve seat portion is The force is applied toward the main valve body, and the distance between the first valve seat and the first main valve body is smaller than the distance between the second valve seat and the second main valve body by the amount of displacement of the elastic member. A pressure reducing valve arranged to be small.