JPH0786779B2 - 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
There are two types: a direct-acting type that serves as an operating part that operates the valve element, and a pilot-acting type that operates the valve main body by adjusting the pressure of the main valve operating part with the direct acting pressure reducing valve as the pilot part. is there. 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, and the valve rod 136 is displaced to open / close 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, the structure of the connecting portion between the piston, that is, the operating portion and the valve body is improved.

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 wall that is composed of a plurality of curved surfaces of the same shape such as a curved surface that bulges outward in the radial direction of the operating rod and that is rotationally symmetrical about the operating rod. ,
The wall formed of the plurality of curved surfaces is formed toward the direction of the fluid ejected from the valve port, and is arranged almost at the center of the fluid ejected.

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.

Each of the curved surfaces forming the connecting wall surface of the movable wall and the operation rod may be a curved surface obtained by bending a flat surface in one direction into an arch, a spherical surface, or an ellipsoidal curved surface. Although a ridge line is formed at the joint between the constituent curved surfaces, the ridge line may be left as it is or may be processed into an R surface to be rounded.

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

The fluid ejected from the valve port goes straight toward the other surface side of the operating portion. Along the way, it hits a connecting surface wall composed of a plurality of curved surfaces such as a curved surface that bulges outward in the radial direction of the operating rod, and flows along the surface. By forming the connecting surface wall with a plurality of curved surfaces having the same shape that bulge outward, the flow becomes smooth and flows down to the outlet. When the connecting surface portion is flat like the conventional example, it receives an ejected fluid at a substantially right angle and is pushed up by the flow, but as in the present invention, it has a plurality of curved surfaces of the same shape. By
The jetted fluid flows down more smoothly to the outlet as compared with the case of a flat surface, 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 curved surface wall, the flow velocity becomes faster as the flow path becomes longer as compared with the conventional planar shape. Therefore,
The static pressure becomes smaller as the flow velocity becomes faster. Then, when the fluid ejected from the valve port goes straight to the connecting curved wall, when the central axis of the connecting curved wall inclines laterally from the central axis of the ejecting fluid, the ejecting fluid flowing along the rotationally symmetrical connecting curved wall. The flow path length of the flow path changes depending on the inclination, and a surface where the flow velocity becomes faster and a surface where the flow velocity becomes slower are generated, and the distribution of static pressure acting on the rotationally symmetrical curved wall becomes non-uniform. Due to the difference, the connecting curved wall is pushed back on the central axis of the jetted fluid. Thus, when the jetted fluid goes straight to the connecting curved wall, the static pressure becomes non-uniform, and the central axis of the connecting curved wall and the central axis of the jetting fluid are located on the same axis, so that the operating part vibrates. The operation portion is smoothly displaced along the central axis of the ejected fluid, and the fluctuation of the secondary 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 portions of 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 FIGS. 1 to 3) In this embodiment, a curved surface wall for connection between a movable wall and an operating rod is formed by six curved surfaces. 1 to 3 show a piston constituting an operating wall and an operating wall of an operating portion of a pressure reducing valve as shown in FIG.

The piston 10 has an upper cylindrical portion 11, an end wall 15, and a piston rod.
18 and a connecting curved wall 16 between the end wall 15 and the piston rod 18. The lower surface side of the piston 10 forming the operation rod is arranged at a position where the fluid ejected from the valve port 114 in FIG. The cylindrical portion 11 is provided with annular grooves 12 and 13 on its outer peripheral surface, and is fitted in the cylinder with a packing ring interposed.

The orifice 14 is provided in the end wall 15 corresponding to the movable wall of the operating portion. The piston rod 18 corresponding to the operating rod is usually a cylinder, but it may be a prism such as a hexagonal prism.

The connecting curved surface wall 16 is composed of six curved surfaces 17, ..., which bulge outward in the radial direction of the piston rod 18, and a radial ridge line 19 of the piston rod 18 is formed at the joint between them. . The curved surfaces 17, ... Are all of the same shape, are positioned rotationally symmetrically around the piston rod 18, and are formed in the direction of the fluid ejected from the valve port, and the center of the connection curved wall 16 is the valve. It is placed almost on the center of the fluid ejected from the mouth.

Embodiment 2 (see FIG. 4) In this embodiment, the curved connection wall between the movable wall and the operating rod is formed by four curved surfaces. FIG. 4 is a bottom view of the piston similar to FIG.

An orifice 24 is provided in an end wall 25 of the piston 20, which corresponds to the movable wall of the operating portion. The piston rod 28 corresponding to the operation rod is usually a cylinder, but it may be a prism such as a square prism.

The connecting curved surface wall 26 is composed of four curved surfaces 27, ..., which bulge outward in the radial direction of the piston rod 28, and the radial ridgeline 29 of the piston rod 28 is formed at their joint. . The curved surfaces 27, ... Are all of the same shape and symmetrically arranged around the piston rod 28.

Embodiment 3 (see FIG. 5) In this embodiment, a curved surface wall for connection between a movable wall and an operating rod is formed by three curved surfaces. FIG. 5 is a bottom view of the piston similar to FIG.

An orifice 24 is provided in an end wall 35 of the piston 30, which corresponds to the movable wall of the operating portion. The connecting curved surface wall 36 is composed of three curved surfaces 37, ... Which bulge outward in the radial direction of the piston rod 38, and at their joints, the radial ridge line 39 of the piston rod 38.
Is formed. The curved surfaces 37, ... Are all of the same shape and are symmetrically located around the piston rod 38.

[Brief description of drawings]

FIG. 1 is a sectional view of a piston of a pressure reducing valve according to an embodiment of the present invention,
2 is a bottom view of the piston of FIG. 1, FIG. 3 is a perspective side view of the piston of FIG. 1 in a direction perpendicular to the line III-III of FIG. 2, and FIG. 4 is a piston of another embodiment. 2 is a bottom view similar to FIG. 2, FIG. 5 is a bottom view similar to FIG. 2 of a piston of yet another embodiment, and FIG. 6 is a cross-sectional view of a conventional pressure reducing valve. 10,20,30: Piston 15,25,35: End wall (movable wall) 16,26,36: Connection curved wall 17,27,37: Curved surface 18,28,38: Piston rod (operating rod) 114: Valve opening 118: Disc 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 arranged at a position where the fluid ejected from the valve port goes straight, and the curved portion is bulged outward in the radial direction of the operating rod. A plurality of curved surfaces having the same shape, such as surfaces, are connected to each other by a wall formed of a plurality of curved surfaces that are rotationally symmetric around the operating rod, and the walls formed of the plurality of curved surfaces are formed in the direction of the fluid ejected from the valve port. At the same time, a pressure reducing valve characterized in that it is arranged almost on the center of the jetted fluid.