JPH0418016Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a pressure reducing valve, that is, an automatic valve that reduces the pressure from the primary side pressure to a predetermined secondary side pressure by changing the opening degree of the valve body using the energy of the fluid itself passing through. Regarding regulating valves.

There are two types of pressure reducing valves: one is a direct-acting type, in which the secondary side pressure detection part itself acts as the operating part that directly operates the valve body, and the other is a direct-acting type, in which the secondary side pressure detection part itself becomes the operating part that directly operates the valve body, and a direct-acting type pressure reducing valve is used as a pilot part to control the pressure of the main valve body operating part. There is a pilot operated type that operates the main valve body by adjusting it. The present invention relates to the structure of the connecting portion between the valve body and the operating section, and is applicable to both direct-operated pressure reducing valves and pilot-operated pressure reducing valves.

The present invention relates to improving the offset characteristics and rated flow characteristics of a pressure reducing valve. The best pressure reducing valve is one with a small offset and a large rated flow rate.

BACKGROUND ART The present applicant has developed a pressure reducing valve in which a movable wall of an operating portion and an operating rod that transmits displacement of the movable wall to a valve body are connected in a substantially hemispherical plane, and has filed a patent application.

In a direct acting pressure reducing valve, the movable wall is the diaphragm itself, and in a pilot operated pressure reducing valve, it is the end wall of the piston. The connecting portion between the movable wall and the operating rod is most preferably a hemispherical surface, but it may also be a spherical surface that is slightly more than a hemisphere, a spherical surface that is somewhat less than a hemisphere, or a hemispherical surface with a cylinder continuing at the rear. A substantially hemispherical surface includes a curved surface that bulges outward from a conical surface, such as a curved surface with an elliptical cross section.

First, this pressure reducing valve will be explained with reference to FIG.

This is a pressure reducing valve for steam, and consists of a pressure reducing valve section 1, a steam/water separator section 2, and a drain valve section 3.

The valve casing 10 forms an inlet 12, a valve port 14, and an outlet 16. The inlet is connected to the high pressure fluid source on the primary side.
The outlet connects to the secondary low pressure area. The main valve body 18 is placed on the valve seat at the inlet side end of the valve port 14 and is elastically biased by a coil spring.

A piston 20 is slidably arranged in the cylinder, and a piston rod 22 is inserted into the main valve body 1 through the valve port 14.
8 and is brought into contact with the central protrusion 23 of No.8. A pilot valve 26 is disposed in a primary pressure passage 24 that communicates the inlet 12 with the upper space of the piston 20, that is, the piston chamber.

The outer peripheral edge of the diaphragm 28 is attached to the flange 3.
Install it by sandwiching it between 0 and 32. The space below the diaphragm 28 passes through the secondary pressure passage 34 to the outlet 1.
6. The head end surface of the valve stem 36 of the pilot valve 26 abuts against the central lower surface of the diaphragm 28. Through a spring seat on the upper surface of the diaphragm 28,
A coil spring 40 for pressure setting is brought into contact. Adjustment screw 44 is threadedly attached to valve casing 10 .

When the adjustment screw 44 is turned left and right, the pressure setting spring 4
The elastic force that pushes down the 0 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 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, and the main valve body 18 is displaced.
Fluid at inlet 12 flows through valve port 14 to outlet 16. This automatically operates so that the valve port 14 opens when the fluid pressure on the secondary side decreases and closes when it increases.

A cylindrical partition member 46 is attached below the valve port 14 to form an annular space 48 between it and the valve casing 10 surrounding it, the upper part of which communicates with the inlet 12 through a cone-shaped screen 50, and the lower part thereof. It 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 48, its direction is bent by the swirl vanes 54 and the fluid is swirled. The liquid is swung outward, hits the inner wall of the surrounding valve casing, 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 toward the valve port 14, where it flows. through which it 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 provided at the top of the float cover 62.
open it.

Therefore, the valve float 60 rises and falls 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.

An orifice 71 is opened in the lower end wall 70 of the piston 20. The lower surface of the lower end wall 70 is formed into a flat surface. The piston rod 22 is a cylinder, and its lower end surface abuts the upper end surface of the valve rod 23.

The lower surface of the lower end wall 70 of the piston 20 forming the movable wall and the piston rod 22 forming the operating rod are connected through a hemispherical surface 72. The hemispherical surface 72 and the lower surface of the lower end wall 70 and the connection portion between the hemispherical surface 72 and the piston rod 22 are connected by an R surface with an extremely small radius or without processing the R surface.

In the pressure reducing valve described above, the fluid ejected from the valve port travels straight toward the movable wall of the operating section. On the way, it almost hits the connecting surface of the hemisphere and flows along that surface. By making the connecting surface almost hemispherical,
The velocity of the fluid flowing over the surface is greater than if the connecting surface were simply planar, and therefore the static pressure is lower than if it were planar. The relationship between fluid velocity and static pressure is such that as the fluid velocity increases, the static pressure decreases, and as the fluid velocity decreases, the static pressure increases.

By making the connection surface almost hemispherical, the pressure difference between the top surface of the movable wall and the top surface of the movable wall increases as the static pressure decreases compared to when the connection surface is flat, and the movable wall and operating rod are drawn downward, that is, toward the valve port. . Therefore, the valve body is moved further away from the valve port by this amount, and the opening degree of the valve port becomes larger.

Furthermore, the connecting hemisphere is centered on itself with respect to the jet flow from the valve port. In other words, when the hemispherical surface is on the central axis of the jet flow, the flow velocity is the same all around, but when it deviates to the side, the flow velocity becomes uneven around the circumference, and the hemispherical surface is pushed back onto the central axis. Static pressure is distributed. Therefore, the movable wall of the operating part and the operating rod are not subjected to vibration or tilted, and are smoothly displaced along the central axis of the jet flow, so fluctuations in the outlet pressure are small and the offset is small. It's also small.

As a result, the movable wall of the operating section and the operating rod are smoothly and largely displaced toward the valve port, resulting in a small offset and a large rated flow rate. Since the movable wall of the operating section and the operating rod are not susceptible to vibration or tilting force, fluctuations in the pressure on the secondary side are small. In addition, there is little wear on sliding contact parts such as the piston and cylinder, and the valve body and valve seat, and good initial operation can be maintained for a long time.

Problems to be Solved by the Present Invention It has been found that the above-mentioned hydrodynamic effect between the jet flow from the valve port and the connecting hemisphere is more pronounced at the lower part of the connecting hemisphere than at the outer periphery. In this respect,
In the above technique, since the operating rod is connected to the bottom of the connecting hemisphere, the above effects cannot be fully exhibited.

The technical problem of the present invention is to ensure that a larger amount of fluid ejected from the valve port flows along the lower spherical surface of the connecting hemisphere.

Means for Solving the Problems The technical means of the present invention taken to solve the above technical problems is to form an inlet, a valve port, and an outlet in a valve casing, and place a valve body opposite the valve port. The movable wall of the operating part and the operating rod that transmits the displacement of the movable wall to the valve element are connected by a substantially hemispherical surface. , the operation rod is formed hollow, and an inlet is opened at the end of the hollow operation rod connected to the valve body, and a spout is opened at the end connected to the connecting hemisphere to communicate with the hollow part. It is.

Effect The operation of the above technical means will be explained.

When the valve port is opened, fluid on the inlet side flows through the valve port to the outlet side. At that time, a part of the fluid that rushes from between the valve body and the valve seat toward the center of the valve port where the operating rod is located jumps into the suction port, passes through the inside of the hollow operating rod, and enters the connecting hemisphere. It is ejected in the radial direction from the ejection port at the bottom. Then, it flows along the lower spherical surface of the connecting hemisphere.

In addition, most of the fluid that rushes toward the center of the valve port does not pass through the hollow part and flows directly along the connecting hemispherical surface, and along with the fluid that reaches the connecting hemisphere through the hollow part, the fluid flows along the hemispherical surface. This causes a decrease in static pressure.

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

As mentioned above, in the pressure reducing valve of the present invention, a part of the fluid in the valve port is guided to the lower spherical surface of the connecting hemisphere through the inside of the hollow operating rod, so that a larger amount of fluid can be more reliably delivered to the lower part of the connecting hemisphere. It can flow along the spherical surface. For this reason, the above-mentioned effects of increasing the rated flow rate, reducing offset, preventing vibration of operating parts such as pistons and valve bodies, and reducing wear of sliding parts can be achieved through cooperation with the almost hemispherical connecting surface. It will be done.

It is possible to make the operating rod thinner in order to more reliably flow a larger amount of fluid along the connecting hemisphere, but making it thinner would cause the rod to bend or become deformed. There are limits to By making the operating rod hollow as in the present invention, the diameter of the operating rod can be increased without increasing the actual cross-sectional area of the operating rod, which prevents it from bending or deforming. almost all of the fluid can flow down to the connecting hemisphere.

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

Embodiment 1 (See FIG. 1) In this embodiment, a hole is made in the operating rod along the axis. Figure 1 shows only the main valve part.
Corresponding parts corresponding to the main valve portion of FIG. 3 are given the same reference numerals.

An orifice 71 is opened in the lower end wall 70 of the piston 20. The lower surface of the lower end wall 70 is formed into a flat surface. The piston rod 22 is a cylinder, and its lower end surface abuts the upper end surface of the valve rod 23. The lower surface of the lower end wall 70 of the piston 20 forming a movable wall and the piston rod 2 forming an operating rod.
2 are connected at a hemispherical surface 72.

The piston rod 22 and valve rod 23, which constitute the operating rod, have
A communication hole 83 is opened along the axis. A plurality of suction ports 8 are provided around the valve stem 23 at the connection end with the valve body 18.
0 is opened, and a plurality of jet ports 81 are opened around the piston rod 22 at its connecting end with the connecting spherical surface 72.

Embodiment 2 (See FIG. 2) In this embodiment, a hollow operating rod is formed by winding a wire into a cylindrical shape. FIG. 2 shows only the main valve portion, and corresponds to the main valve portion in FIG. 3, and corresponding parts are given the same reference numerals.

An orifice 71 is opened in the lower end wall 70 of the piston 20. A hemispherical surface 72 is formed on the lower surface of the lower end wall 70. A circular hole is made in the lower end of the connecting hemisphere 72 and the upper surface of the valve body 18, and a hollow operating rod 90, which is made by winding a wire into a cylindrical shape and has a communication hole 93 formed inside, is inserted and attached.

In the operating rod 90, adjacent wires are in close contact with each other at the center, and there is a gap between the adjacent wires at both ends, that is, the suction port 91.
Wrap the wire so that the spout 92 is formed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main valve part of a pressure reducing valve according to an embodiment of the present invention, FIG. 2 is a sectional view of the main valve part of another embodiment, and FIG. 3 is a sectional view of a conventional pressure reducing valve. 14... Valve port, 18... Valve body, 20... Piston, 22... Piston rod (operating rod), 23... Valve rod (operating rod), 72... Connection hemisphere, 90... Operating rod, 80, 91... Suction port, 81, 92... Spout port, 83, 93... Distribution hole.

Claims (1)

[Scope of utility model registration request] An inlet, a valve port, and an outlet are formed in a valve casing, and a valve body is disposed opposite the valve port, and the valve body cooperates with the operating section to open and close the valve port. The movable wall and an operating rod that transmits the displacement of the movable wall to the valve body are connected with a substantially hemispherical surface, the operating rod is formed hollow, and an inlet is opened at the connecting end of the hollow operating rod with the valve body, A pressure reducing valve having a spout opening at the end connected to the connecting hemisphere and communicating with the hollow part.