JP2699027B2 - Cage valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cage valve which is one type of a control valve for closing and controlling the flow of various fluids in a pipeline, and more particularly to a cage valve having a small valve leakage. The cage valve controls the flow of the fluid to regulate the flow rate, pressure, temperature, etc., and when closed, completely closes the flow of the fluid. Used.

[0002]

2. Description of the Related Art As a conventional cage valve, for example, Japanese Patent Publication No.
There is one disclosed in Japanese Patent Publication No. 18470. This is achieved by disposing a cage having a cylindrical peripheral wall in a valve chamber, providing a window and a plurality of valve seats on the peripheral wall for passing a fluid, disposing a valve plug in the cage, and disposing the valve plug. And a through hole communicating the valve plug up and down, and sliding the valve plug up and down to control the flow by changing the opening area of the fluid passage window. It is. The pressure difference acting in the up and down operation direction acts almost equally on the top and bottom of the valve plug by the through hole of the valve plug, and is canceled out, and hardly acts on the valve plug. When the valve is closed, the valve plug is brought into close contact with the valve seat to prevent fluid leakage.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
There has been a problem that valve leakage cannot be completely eliminated when the valve is closed. This is because when high-pressure fluid passes through, especially when the valve opening is small, the flow path is restricted at the valve seat and the seating portion, and high-speed fluid flows down, causing erosion damage, and in a short time. This is because the airtightness between the two is reduced, and valve leakage occurs.

Accordingly, it is an object of the present invention to provide a cage valve which does not cause valve leakage for a long period of time even when controlling a high-pressure fluid.

[0005]

Means for Solving the Problems The technical means of the present invention taken to solve the above technical problem is to form an inlet, a valve chamber and an outlet in a valve casing, and to provide a fluid passage window in the valve chamber. And arrange a cylindrical cage with a valve seat above and below this window,
An inverted cup-shaped valve plug provided with a seat portion slidably in the cage and opposed to the valve seat, and a through hole communicating with the inside of the cage is provided at an upper portion of the valve plug. A flat sub-valve seat is provided at the lower end in the cage, and a disc-shaped sub-valve facing the sub-valve seat is provided in the inverted cup-shaped valve plug, and the valve is opened later than the valve plug is opened. The disc-shaped sub-valve is elastically biased in the valve-closing direction with respect to the sub-valve seat so as to close before the valve plug is closed.

[0006]

The operation of the above technical means is as follows.
By providing a sub-valve that opens after the valve plug is opened and closes before closing the valve plug, the sub-valve is closed even when the valve plug is slightly opened. High-speed fluid does not flow down between the plug seat and valve seat,
Therefore, no erosion damage occurs. Also,
Even when the valve plug goes from opening to closing, the sub-valve closes prior to closing the valve plug, so that the flow path of the valve plug is not restricted, thus causing erosion damage. Nothing.

[0007]

An embodiment showing a specific example of the above technical means will be described (see FIG. 1). Inlet 2 and valve chamber 3 in valve casing 1
And an outlet 4 are formed. A cylindrical cage 5 is mounted in the valve chamber 3. The cage 5 is provided with a window 6 for fluid passage and valve seats 7 and 8 above and below the window 6. At the lower end of the cage 5, a sub-valve seat 13 having a flat plate shape and having a through hole 15 at the center is attached. An inverted cup-shaped valve plug 9 is slidably disposed in the cage 5. The valve plug 9 has a seating portion 10 facing the valve seats 7 and 8,
11 is provided, and a through hole 12 communicating with the inside of the cage 5 is provided at the upper part.
Is provided. In the valve plug 9, a disc-shaped sub-valve 16 is arranged so as to face the sub-valve seat 13. The sub-valve 16 is integrally formed by press-fitting a spring holding member 17 having a T-shaped cross section, and the other end of the spring holding member 17 is arranged in contact with the coil spring 20. The other end of the coil spring 20 is in contact with the inner wall of the valve plug 9 and
To the auxiliary valve seat 13 in the valve closing direction. A ring 23 for lifting the sub-valve 16 is attached to the inner periphery of the valve plug 9. The inner diameter of the ring 23 is smaller than the outer diameter of the spring holding member 17 so that both the valve plug 9 and the sub-valve 16 can be displaced upward after the valve plug 9 is displaced upward by a predetermined amount. An operation rod 25 for operating the valve plug 9 from outside is attached to the upper part of the valve plug 9.

When the valve plug 9 is opened by the operating rod 25 in a small amount, the sub-valve 16 is in a closed state because it is urged by the coil spring 20, and almost no fluid flows from the inlet 2 to the outlet 4. The flow velocity of the fluid passing between the seats 10, 11 of the valve plug 9 and the valve seats 7, 8 is low, so that there is no erosion damage. In this case, the auxiliary valve 16
It is not always necessary to completely close the gap between the valve seat and the sub-valve seat 13, and there may be some leakage or escape.

When the valve plug 9 is further operated upward, the ring 23 comes into contact with the spring pressing member 17, and the sub-valve 16 is displaced upward together with the valve plug 9, so that a large amount of fluid at the inlet 2 flows down. In this case, since the distance between the valve plug 9 and the valve seats 7 and 8 is large, the flow path is not extremely narrowed, and no erosion damage is caused by the high-speed flow.

[0010]

The present invention has the following specific effects. As described above, according to the present invention, by providing the sub-valve that opens after the valve plug is opened and closes before the valve is closed, a gap between the seating portion and the valve seat portion of the valve plug is provided. The high-speed fluid does not flow down, and erosion damage does not occur. Therefore, the initial high sealing performance can be maintained for a long time, and no valve leakage occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of a cage valve of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 valve casing 2 inlet 4 outlet 5 cage 6 window 7, 8 valve seat 9 valve plug 10, 11 seating portion 13 auxiliary valve seat 16 auxiliary valve 20 coil spring 23 ring

Claims (1)

(57) [Claims] An inlet, a valve chamber, and an outlet are formed in a valve casing, a fluid passage window is disposed in the valve chamber, and a cylindrical cage having valve seats provided above and below the window is disposed in the valve casing. An inverted cup-shaped valve plug provided with a seat portion movably and opposed to the valve seat is disposed , and communicates with the upper part of the valve plug in the cage.
With a through hole, a flat plate at the lower end in the cage
A sub-valve seat is provided, and a disc-shaped sub-valve opposite to the sub-valve seat is provided in the inverted cup-shaped valve plug. A cage valve characterized in that the disk-shaped auxiliary valve is elastically biased in a valve closing direction with respect to the auxiliary valve seat so as to close the valve prior to the valve closing.