JPH0786778B2 - Pressure reducing valve - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve, that is, an automatic pressure reducing device that changes the opening degree of a valve body by the energy of a passing fluid itself to reduce the pressure from a primary pressure to a predetermined secondary pressure. Regarding regulator valve.

As a pressure reducing valve, the secondary pressure detector itself is directly
Direct-acting type, which serves as the operating part that operates the valve element, and pilot-acting type, which operates the main valve element by adjusting the pressure of the main-valve operating part with the direct-acting pressure reducing valve as the pilot part. There is. The present invention relates to the structure of the connecting portion between the valve element and the operating portion, and can be applied to both a direct acting type pressure reducing valve and a pilot operated type pressure reducing valve.

The present invention relates to improvement of offset characteristics and rated flow characteristics of pressure reducing valves. Air Conditioning and Sanitary Engineering Society Standard, HASS 106-197
In 8, the terms are defined as follows.

Minimum adjustable flow rate: Minimum flow rate of pressure reducing valve that can maintain stable flow state Set pressure: Secondary side pressure at minimum adjustable flow rate Offset: Minimum adjustment of flow rate while maintaining constant primary side pressure The difference between the secondary pressure and the set pressure that change when the flow rate is gradually increased from the possible flow rate to the rated flow rate of the pressure reducing valve. Rated flow rate: When the primary pressure is constant, the maximum flow rate that can be guaranteed within the specified offset. In terms of the above meaning, a valve having a small offset and a large rated flow rate is excellent.

2. Description of the Related Art The applicant has developed a pilot operated pressure reducing valve shown in FIG. This is a pressure reducing valve for steam, and is composed of a pressure reducing valve unit 101, a steam separator unit 102, and a drainage valve unit 103.

The valve casing 110 forms an inlet 112, a valve opening 114, and an outlet 116. The inlet is connected to the high pressure fluid source on the primary side and the outlet is connected to the low pressure region on the secondary side. The valve port is formed by a valve seat member.

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

The piston 120 is slidably arranged in the cylinder 122, and the piston rod is brought into contact with the main valve body 118 through the valve port 114. A pilot valve 126 is arranged in a primary pressure passage 124 that connects the inlet 112 and the upper space of the piston 120, 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 the secondary pressure passage 134.

The head end face of the valve rod 136 of the pilot valve 126 is the diaphragm 12
Abut the lower surface of the center of 8.

A coil spring 140 for pressure setting is brought into contact with the upper surface of the diaphragm 128 via a spring seat 138. The adjusting screw 144 is screwed and attached to the valve casing 110.

When the adjusting screw 144 is turned to the left or right, the elastic force that pushes down the diaphragm 128 of the pressure setting spring 140 changes. With the elastic force of the pressure setting spring 140 as a reference value, the diaphragm 128 bends in accordance with the secondary pressure acting on the lower surface of the diaphragm 128, which displaces the valve rod 136 and opens and closes the pilot valve 126. As a result, the primary fluid pressure is introduced into the piston chamber and the piston
120 is driven, the main valve body 118 is displaced, and the inlet 112
Fluid flows through the valve port 114 to the outlet 116. This automatically operates so that the valve opening 114 opens when the fluid pressure on the secondary side drops and closes when the fluid pressure rises.

A cylindrical partition member 146 is attached below the valve opening 114, and an annular space 148 is formed between the partition wall member 146 and the valve casing 110 that surrounds the partition wall member 146, the upper part of which communicates with the inlet 112 through the cone-shaped screen 150, and the lower part of the drainage. It communicates with the upper part of the valve chamber 152.

Further, the upper portion of the drain valve chamber 152 communicates with the valve port 114 through the central opening of the partition member 146. In the annular space 148, swirl vanes 154 composed of inclined walls are arranged.

Therefore, the fluid at the inlet 112 is opened in the annular space 14 with the valve opening 114 open.
When passing through 8, the direction is bent by the swirl vanes 154 and swung. The liquid is swirled to the outside, hits the inner wall of the surrounding valve casing and flows down into the drain valve chamber 152, and the light gas swirls in the central portion toward the valve opening 114 from the central opening of the partition member 146 and passes therethrough. Exit at exit 116.

At the bottom of the drain valve chamber 152, the drain valve port 15 leading to the drain port 156
Forming eight. The float valve 162 is covered to accommodate the spherical valve float 160 in a displaceable manner. A ventilation hole 164 is formed in the upper portion of the float cover 162.

Therefore, the valve float 160 floats down along with the water level in the drain valve chamber 152 to open and close the drain valve port 158, and automatically removes the water accumulated in the drain valve chamber 152.

Problems to be Solved by the Invention The flow rate characteristics of the pressure reducing valve have a relatively large offset,
The rated flow rate is relatively small, which is not much different from the conventional pressure reducing valve.

It is presumed that the cause of the limit of the flow rate characteristic is that when the piston is displaced downward and the main valve body is pushed down, the fluid ejected from the valve opening is received, and the fluid is pushed up and vibrated.

Therefore, in order to improve the flow rate characteristic, it is necessary to improve the structure of the connecting portion between the piston, that is, the operating portion and the valve body.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is to form an inlet, a valve opening, and an outlet in a valve casing, and dispose a valve body facing the valve opening. Then, an operating portion for operating the valve body is provided, and the primary side pressure is applied to one surface of the operating portion and the secondary side pressure is applied to the other surface to operate the valve body, thereby opening and closing the valve opening. In an automatic adjustment valve for reducing the secondary side pressure to a predetermined value, the other side of the operating portion is arranged at a position where the fluid ejected from the valve port goes straight, and the movable wall of the operating portion and the displacement of the movable wall are arranged. The operating rod that is transmitted to the valve body is connected by a substantially hemispherical surface, the hemispherical surface is formed in the direction of the fluid ejected from the valve opening, and the hemispherical surface is arranged almost at the center of the fluid.

The movable wall is the diaphragm itself in the direct acting pressure reducing valve, and is the end wall of the piston in the pilot operated pressure reducing valve.

The hemispherical surface is most preferable for the connecting portion between the movable wall and the operating rod,
It may be a sphere slightly beyond a hemisphere, a sphere slightly less than a hemisphere, or a hemisphere with a cylinder at the rear.

If the curved surface bulges outside the conical surface, such as a curved surface having an elliptical cross section, the following operational effects can be obtained. Therefore, the substantially hemispherical surface also includes these curved surfaces.

Action The action of the above technical means will be described.

The fluid ejected from the valve port goes straight to the other surface side of the operating portion. Along the way, it hits a hemispherical connecting surface and flows along the surface. By making the connection surface almost hemispherical, the flow becomes smooth and flows down to the outlet. When the connection surface is flat as in the conventional example, it receives the ejected fluid at a substantially right angle and is pushed up by the flow of the ejected fluid. Compared to the flat case, the action more smoothly flows down to the outlet, and the action of pushing up the operating portion by the flow is reduced. Therefore, the opening degree of the valve opening increases by the rate at which this pushing-up action is reduced.

Further, when the fluid ejected from the valve port flows along the connecting hemisphere, the flow velocity is increased by the length of the flow path as compared with the conventional planar one, which is a hemisphere. Therefore, the static pressure becomes smaller as the flow velocity becomes faster.
Then, in the case where the fluid ejected from the valve port goes straight to the connecting hemisphere, when the central axis of the connecting hemisphere is tilted laterally from the central axis of the ejecting fluid, the ejecting fluid flowing along the hemisphere into the hemisphere is The flow path length changes according to the inclination, and the surface where the flow velocity becomes faster and the surface where the flow velocity becomes slower occur, and the distribution of the static pressure acting on the hemisphere becomes non-uniform. The surface is pushed back onto the central axis of the ejected fluid. In this way, when the ejected fluid goes straight to the connecting hemisphere, the static pressure becomes non-uniform, and the central axis of the connecting hemisphere and the central axis of the ejected fluid are positioned on the same axis, causing the operating part to vibrate. The operation portion is smoothly displaced along the center of the jetted fluid, the fluctuation of the secondary side pressure is small, and the offset is also small.

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

Since the movable wall of the operating portion and the operating rod are smoothly and largely displaced toward the valve opening side, the offset is small and the rated flow rate is large.

Since the movable wall of the operation unit and the operation rod are less susceptible to vibration and tilting force, the fluctuation of the secondary pressure is small. Further, wear of the sliding contact parts such as the piston and the cylinder, the valve body and the valve seat, etc. is small, and the initial good operation is maintained for a long time.

Example An example showing a specific example of the above technical means will be described.

Embodiment 1 (see FIG. 1) In this embodiment, the connecting surface between the movable wall and the operating rod is formed into a hemispherical surface. FIG. 1 shows only the main valve portion, and corresponds to the main valve portion in FIG. 4, and corresponding members are designated by the same reference numerals.

A groove is formed on the peripheral wall of the piston 120 to form the piston rings 12, 13
And the orifice 11 is opened in the lower end wall 16. Bottom wall
The lower surface of 16 is formed into a flat surface. The piston rod 14 is a cylinder, and the lower end surface of the piston rod 14 contacts the upper end surface of the valve rod 15.

The lower surface of the lower end wall 16 of the piston 120 forming the movable wall and the piston rod 14 forming the operating rod are connected by the hemispherical surface 10. Further, the lower surface side of the piston 120 of the operation portion is arranged at a position where the fluid ejected from the valve port 114 goes straight. The hemispherical surface 10 is formed in the direction of the fluid ejected from the valve port 114, and the center of the hemispherical surface 10 is arranged substantially above the center of the fluid ejected from the valve port 114.
Hemisphere 10 and bottom surface of bottom wall 16, hemisphere 10 and piston rod 14
The connection part with is an R surface with an extremely small radius, or
Connect without surface processing.

To illustrate the dimensions of a typical part, the outer diameter of the piston 120 is 4
7 mm, outer diameter of piston rod 14 is 7 mm, inner diameter of valve port 114 is 20 m
m, the width is 16 mm, the distance from the lower surface of the lower end wall 16 to the valve surface of the valve body 118 with the piston rod 14 and the valve rod 15 in contact with each other is 50 mm, and the radius of the connecting spherical surface 10 is 14 mm.

Embodiment 2 (see FIG. 2) In this embodiment, the connecting surface between the movable wall and the operating rod is formed as a 3/4 hemisphere. FIG. 3 shows only the main valve portion and corresponds to the main valve portion in FIG. 4, and corresponding members are designated by the same reference numerals.

Grooves are formed on the peripheral wall of the piston 120 to form piston rings 22, 23
And the orifice 21 is opened in the lower end wall 26. Bottom edge
The lower surface of 26 is formed flat. The piston rod 24 is a cylinder, and the lower end surface of the piston rod 24 contacts the upper end surface of the valve rod 25.

The lower surface of the lower end wall 26 of the piston 120 forming the movable wall and the piston rod 24 forming the operating rod are connected by a 3/4 hemisphere surface 20. Hemisphere 2
The connecting portion between 0 and the lower surface of the lower end wall 16 is connected by the R surface. This allows the fluid to smoothly change direction. The connecting portion between the hemispherical surface 20 and the piston rod 24 is connected with an R surface having an extremely small radius or without processing the R surface.

Embodiment 3 (see FIG. 3) In this embodiment, the connecting surface between the movable wall and the operating rod is formed by a hemispherical surface in which a cylinder is connected to the rear portion. FIG. 3 shows only the main valve portion, and corresponds to the main valve portion of FIG. 4, and corresponding members are designated by the same reference numerals.

A groove is formed on the peripheral wall of the piston 120 to form the piston rings 32, 33.
And the orifice 31 is opened in the lower end wall 16. Bottom wall
The lower surface of 36 is formed into a flat surface. The piston rod 34 is a cylinder, and the lower end surface of the piston rod 34 contacts the upper end surface of the valve rod 35.

The lower surface of the lower end wall 36 of the piston 120 forming the movable wall and the piston rod 34 forming the operating rod are connected by a hemispherical surface 30 which is followed by a cylinder. The cylindrical surface, the lower surface of the lower end wall 36, and the connecting portion between the hemispherical surface 30 and the piston rod 34 are connected by the R surface.

[Brief description of drawings]

FIG. 1 is a sectional view of a main valve portion of a pressure reducing valve of an embodiment of the present invention, FIG. 2 is a sectional view of a main valve portion of another embodiment, and FIG. 3 is a main valve portion of yet another embodiment. A sectional view and FIG. 4 are sectional views of a conventional pressure reducing valve. 10,20,30: Connected hemisphere 14,24,34: Piston rod 114: Valve opening 118: Valve body 120: Piston

Claims (1)

[Claims] 1. A valve casing is provided with an inlet, a valve opening and an outlet, a valve element is arranged facing the valve opening, and an operating portion for operating the valve element is provided, and a primary side pressure is provided on one surface of the operating portion. By operating the valve body by applying the secondary pressure to the other surface and operating the valve element, the other side of the operating part is adjusted in the automatic adjustment valve that opens and closes the valve port to reduce the secondary pressure to a predetermined value. The movable wall of the operating portion and the operating rod for transmitting the displacement of the movable wall to the valve body are connected to each other in a substantially hemispherical position by arranging at a position where the fluid ejected from the valve opening goes straight, and the hemispherical surface is connected to the valve opening. A pressure reducing valve which is formed in the direction of the fluid ejected from the nozzle and is arranged substantially on the center of the ejected fluid.