JPH05113828A - Valve body guide structure of pressure reducing valve - Google Patents

Abstract

PURPOSE:To provide the valve body guide structure of the pressure reducing valve which securely seals a valve opening by the valve body even if a valve shaft as a guide rod becomes eccentric and causes no valve leak without flawing the surface of the valve body for a long period. CONSTITUTION:The valve shaft 16 which is formed as a different body is arranged below the valve body 12. The valve body 12 and valve shaft 16 are joined together on a nearly hemispherical surface and a nearly comic surface. A valve rod 18 is formed at the lower end of the valve body 12. A through hole 19 is formed in the center part of the valve shaft 16. The valve rod 18 of the valve body 12 is loosely fitted in the through hole 19. The lower end of the valve shaft 16 is fitted slidably in a valve shaft guide 20. The valve body 12 is energized by a coil spring 22 to the valve opening 4 through the valve shaft 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve used in a fluid system, and more particularly to a valve body guiding structure for seating a valve body on a valve opening.

In a pressure reducing valve, pressure on the outlet side is applied to one surface of a pressure responsive member formed of a diaphragm or bellows, and elastic force of pressure setting means formed of a coil spring or the like is applied to the other surface of the pressure responsive member. Depending on the balance of both loads, the pressure responsive member is displaced to open and close the valve body, and the supply of high pressure fluid on the inlet side is stopped to maintain the outlet side at a predetermined depressurized state. It is widely used in fluid systems such as steam.

The pressure reducing valve decompresses the high pressure inlet side fluid and supplies it to the outlet side. However, if the valve body does not close the valve opening surely when the valve is closed, it should be originally supplied to the outlet side. The high pressure inlet side fluid that should not be leaked and the outlet side of the pressure reducing valve becomes a high pressure state at the same level as the inlet side, so-called dead pressure increase occurs, and various devices connected to the outlet side are damaged. And other inconveniences occur.

[0004]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Laid-Open No. 61-155910.
A valve body guiding structure as shown in No. 1 was used. This consists of a valve body and a guide rod that guides the valve body.
Even if the guide rod is eccentric, the valve body is securely seated on the valve opening surface by being connected by a monkey joint so as to prevent valve leakage.

[0005]

In the above-mentioned conventional device, it is possible to surely prevent leakage at the initial stage of use, but there is a problem that valve leakage occurs as the period of use elapses. This is because the valve body is unevenly worn and the seal surface of the valve body is damaged. That is, in the above-mentioned conventional one, since the valve body and the guide rod are connected via the universal joint, the valve body is valved by the influence of the fluid flowing down the valve mouth when the valve body is opened, especially when it is fully opened. The valve body is tilted non-parallel to the mouth surface, and when the valve is subsequently closed, the valve body remains closed with a large tilt, and the valve body seats on the valve mouth with one end of the valve port as the fulcrum and the other end impacted. As a result, uneven wear occurs and damage is caused.

Therefore, a technical problem of the present invention is that the valve opening can be surely closed even if the guide rod is eccentric, and the eccentric wear of the valve body is prevented so that the valve leakage does not occur for a long time. It is to be.

[0007]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problem is to form an inlet, a valve opening and an outlet by valve casing, and to face the valve opening. A valve body is arranged, and a pressure responsive member that cooperates with the valve body is provided. One surface of the pressure responsive member is loaded with pressure on the outlet side, and the other surface is loaded with the setting force of the pressure setting means, and the outlet side is provided. When the pressure drops below a predetermined value, the pressure response member is displaced to open the valve element and supply the high pressure fluid on the inlet side to the outlet side to recover the pressure on the outlet side, and the pressure on the outlet side is kept to a predetermined value. When the valve body closes when the value is restored, the valve body closes, so in the pressure reducing valve that maintains the desired pressure reduction state on the outlet side, a valve shaft formed separately is provided at the bottom of the valve body, and both are substantially hemispherical. Along the conical surface, a through hole is formed in the center of the valve shaft, and the lower end of the valve body is extended into the through hole. A valve rod is loosely fitted, the valve shaft is slidably fitted to a valve shaft guide formed in the valve casing, and the valve shaft or valve element is biased toward the valve opening by a spring. is there.

[0008]

The operation of the above technical means is as follows.
The valve element is elastically biased toward the valve opening by a spring directly or via the valve shaft, and if there is no action of the pressure responsive member, it will contact the valve opening surface by the force of the spring and the fluid pressure on the inlet side. There is. When the pressure on the outlet side becomes lower than the value set by the pressure setting means, the pressure responsive member is displaced and the valve body is opened. When the valve body opens, the valve body is joined to the valve shaft with a substantially hemispherical surface and a substantially conical surface, and the valve rod is loosely fitted in the through hole in the central portion of the valve shaft, so that the valve body is attached to the valve shaft. On the other hand, the valve is opened in a state in which it can be displaced by the amount of loose fitting of the valve rod. Therefore, unlike the case where the valve rod is not loosely fitted, the valve body does not largely open due to the influence of the fluid flow. When the pressure on the secondary side reaches the set value, the pressure responsive member is displaced to the original position. The valve body is pushed up toward the valve opening by the spring and fluid pressure. At this time, the valve body is not greatly tilted under the influence of the flow, so that the entire valve face is seated almost at the same time without being shockedly seated on the valve opening. Even if the valve shaft is slightly eccentric to the valve shaft guide,
Since the valve body is joined to the valve body by the substantially hemispherical surface and the substantially conical surface, the valve body can be eccentric within the range where the valve rod is loosely fitted, and is in close contact with the valve port surface.

[0009]

Since the valve body and the valve shaft are joined by the substantially hemispherical surface and the substantially conical surface, they can be eccentric, and the valve body is not directly affected by the eccentricity of the valve shaft, and the valve leakage is prevented. The valve rod of the valve body and the through hole of the valve shaft are loosely fitted to each other, so that the valve body does not tilt significantly at the time of valve opening, especially at the time of full opening, and at the time of valve closing. Does not damage the valve surface by seating the entire valve surface almost at the same time.
It is possible to prevent valve leakage for a long period of time.

[0010]

EXAMPLES Examples showing specific examples of the above technical means will be described. FIG. 1 shows the main part of the valve section. The valve casing 1 forms an inlet portion 2 that communicates with an inlet (not shown), an outlet portion 3 that communicates with an outlet, and a valve opening 4. The valve port 4 is provided in the central portion where the valve seat 5 is screwed to the valve casing 1. A disk-shaped valve body 12 is arranged so as to face the valve opening 4. The lower end surface of the valve seat 5 and the upper end surface of the valve body 12 are seal surfaces. The lower portion of the valve body 12 is formed in a substantially hemispherical surface 13, and a rod-shaped valve rod 18 is extended to the lower portion of the substantially hemispherical surface 13 and a connecting rod 15 is provided in the upper portion. The substantially conical surface 17 of the valve shaft 16 is joined so as to face the substantially hemispherical surface 13 of the valve body 12. In the valve shaft 16, a through hole 19 is formed below a substantially conical surface 17 to loosely fit the valve rod 18, and a step portion 25 is formed at the upper end. The lower portion of the valve shaft 16 is formed in a shaft shape, and the valve shaft guide 2 attached to the valve casing 1
It is slidably arranged in the 0 guide hole 21. A coil spring 22 is provided between the valve shaft guide 20 and the step portion 25 of the valve shaft 16 to urge the valve body 12 toward the valve port 4 via the valve shaft 16 and the joint portion.

A piston 6 is provided on the upper portion of the outlet 3 as a cylinder.
Place in 7. A piston ring 8 and a tension ring 9 are attached to the piston 6, and a lower portion of the piston 6 is formed into a substantially hemispherical shape 10 and an operating rod 11 is extended. Operating rod 1
The lower end of 1 has a spherical shape and is in contact with the connecting rod 15 provided on the valve body 12. A communication hole 23 that communicates the upper surface and the lower surface of the piston 6 is formed in the center of the piston 6.

Next, the operation will be described. The setting force of the pressure setting means that is applied to the pressure response unit (not shown) and the outlet side portion 3
When the balance with the pressure of the high pressure side is lost, that is, when the pressure of the outlet side portion 3 falls below a predetermined value, the pressure responsive member (not shown) is displaced and the pilot valve (not shown) is also opened to open the high pressure inlet. The fluid of the side part 2 is supplied to the upper surface of the piston 6. The high pressure fluid displaces the piston 6 downward, the valve body 12 also displaces downward and opens the valve opening 4, and the high pressure fluid of the inlet side portion 2 is replenished to the outlet side portion 3 to recover the pressure. In this case, since the valve rod 18 of the valve body 12 is loosely fitted in the through hole 19 of the valve shaft 16, even if the flowing-down fluid flows violently, it does not largely tilt.

When the outlet side portion 3 reaches a predetermined pressure, the pressure responsive portion returns to its original position, the pilot valve closes, the supply of high pressure fluid to the upper surface of the piston 6 is stopped, and the pressure on the upper surface of the piston 6 is reduced. By being discharged from the communication hole 23, the valve body 12 and the valve shaft 16 are brought into close contact with the seal surface of the valve seat 5 due to the pressure difference between the coil spring 22 and the inlet / outlet. In this case, the valve body 12
Is not largely inclined, and almost the entire surface is seated on the valve seat 5 at the same time, so that shocking seating with one end as a fulcrum does not occur and uneven wear does not occur. Also,
Even if the valve shaft 16 is eccentric for the clearance for sliding in the guide hole of the valve shaft guide 20, the valve body 12 and the valve shaft 16 are joined by the substantially hemispherical surface 13 and the substantially conical surface 17. for,
The valve body 12 can be eccentric, absorbs the eccentricity of the valve shaft 16 and surely adheres to the seal surface of the valve seat 5 to prevent leakage.

In the present embodiment, since the through hole 19 is provided in the central portion of the valve shaft 16, dust in the fluid is formed at the joint between the valve body 12 and the valve shaft 16 where the substantially hemispherical surface and the substantially conical surface are joined. Even if foreign matter such as rust or rust enters, the foreign matter falls in the through hole 19, so that the foreign matter is not caught in the joint portion and a smooth joint state can be maintained. Further, in the present embodiment, the piston 6 and the valve body 12 are joined via the operating rod 11 and the connecting rod 15, but the operating rod 1 of the piston 6
By extending 1 it is possible to eliminate the connecting rod 15 and join it to the center of the surface of the valve body 12. in this case,
It is also possible to join the lower end of the operating rod 11 as a concave or convex spherical surface, a conical surface, or a flat surface, and the opposing surface of the valve body 12 as a convex or concave spherical surface, a conical surface, or a flat surface.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a valve body guide structure for a pressure reducing valve according to the present invention.

[Explanation of symbols]

 1 Valve casing 2 Inlet side part 3 Outlet side part 4 Valve port 5 Valve seat 6 Piston 12 Valve body 13 Approximately hemispherical surface 16 Valve shaft 17 Approximately conical surface 18 Valve rod 19 Through hole 20 Valve shaft guide 22 Coil spring

Claims (1)

[Claims] 1. A valve casing is used to form an inlet, a valve opening and an outlet, a valve element is arranged facing the valve opening, and a pressure responsive member cooperating with the valve element is provided. When the pressure on the outlet side is applied to one surface and the setting force of the pressure setting means is applied to the other surface, and when the pressure on the outlet side falls below a predetermined value, the pressure responsive member is displaced and the valve body is opened to open the inlet. Side high pressure fluid is supplied to the outlet side to recover the pressure on the outlet side, and when the pressure on the outlet side recovers to a predetermined value, the valve body closes to reduce the pressure on the outlet side to a desired depressurized state. In the valve, a valve shaft formed separately is provided in the lower part of the valve body, both are joined by a substantially hemispherical surface and a substantially conical surface, and a through hole is formed in the central portion of the valve shaft. A valve rod extended to the lower end of the body is loosely fitted, and the valve shaft is slidably fitted to a valve shaft guide formed on the valve casing. The valve element guide structure of the pressure reducing valve, which is arranged in the above-mentioned manner and in which the valve shaft or the valve element is biased toward the valve opening by a spring.