JPH0218469B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cage valve having a function of preventing vibration of a valve plug sliding inside the cage.

[Prior art]

Conventionally, this type of cage valve has been constructed as shown in FIG. A hole is provided, and valve seats 4 and 5 having different diameters are provided above and below this window 3. Reference numeral 6 denotes a valve plug that slides in the vertical direction by a valve shaft 7, and is disposed in the cage 1 so as to be able to move forward and backward, and has seating portions 8 on its outer peripheral surface that can be seated on both the valve seats 4 and 5, respectively. 9 is provided. Thereby, the opening area of the fluid passage window 3 is changed to control the flow rate. Reference numeral 10 denotes a through hole that communicates between the upper and lower parts of the valve plaza 6, which is bored in the upper part of the valve plug 6, thereby reducing the pressure difference generated on both the upper and lower sides, and separating the two through the valve shaft 7. This reduces the load on a drive unit (not shown) disposed at the location. 11 is an annular groove that opens inside the cage 1, and is provided between the upper valve seat 4 and the window 3 on the inner peripheral surface of the cage 1, and is provided between the outer peripheral surface of the valve plug 6 on the inner peripheral surface of the cage 1. The structure is such that fluid entering the tank will not seep into the top due to a pressure drop. This prevents the valve plug 6 from vibrating within the cage 1.

However, in the conventional cage valve, although it is possible to prevent vibration of the valve plug 6 when the valve plug 6 is slightly raised at a small opening, when the valve plug 6 is fully opened or when the inner peripheral surface of the cage 1 and the outer periphery of the valve plug 6 When a fluid with a high differential pressure enters between the surfaces, there is a disadvantage that the vibration cannot be prevented.

[Summary of the invention]

The present invention has been made in view of the above circumstances, and provides a cage valve that can reliably prevent vibration of the valve plug within the cage by an extremely simple structure in which an eccentric groove is provided on the outer circumferential surface of the valve plug. be. Hereinafter, the configuration and the like will be explained in detail by referring to embodiments shown in the drawings.

〔Example〕

FIG. 2 is a sectional view showing a cage valve according to the present invention;
FIG. 3 is a cross-sectional view of FIG. 2. In these figures, the same members as in FIG. 1 are denoted by the same reference numerals, and detailed explanations are omitted. Reference numeral 21 denotes an eccentric groove that opens on the peripheral wall 2 side of the cage 1, and is provided on the outer peripheral surface of the valve plug 6 between both the seating portions 8 and 9, and the groove bottom 22 is located on the cylindrical side of the valve plug 6. It is formed by a cylindrical surface that is eccentric to the surface.

In the cage valve configured in this way, when the valve is opened, that is, when the valve seats 4, 5 and the seating parts 8, 9 are separated, after the fluid passes through the window 3, the space between the valve seat 5 and the seating parts 9 is a flow A that passes through and reaches the outlet 1a;
It passes through the gap between the outer peripheral surface of the valve plug 6 and the inner peripheral surface of the cage 1, flows between the valve seat 4 and the seating part 8, enters the upper cavity 23 of the valve plug 6, and enters the through hole 10. The flow passes through the valve plug 6 and is divided into a flow B that joins the flow A. At this time, since a large amount of fluid flows between the cage 1 and the valve plug 6 in which a wide gap is formed, the valve plug 6
A pressure difference is created around the valve plug 6, and this pressure difference acts on the valve plug 6 in one direction.

Therefore, while the fluid is flowing through the gap between the valve plug 6 and the cage 1, even if there are pressure fluctuations in the fluid, the state of pressing the valve plug 6 in one direction is almost never released. do not have.

Note that if the eccentric groove 21 is formed by casting with the same groove width over the entire circumference, there is no need to perform groove machining, and there is also the effect that mechanical finishing of the entire valve plug 6 can be easily performed.

〔Effect of the invention〕

As explained above, according to the present invention, an eccentric groove is provided between both seating portions on the outer circumferential surface of the valve plug, so that fluid entering the gap between the outer circumferential surface of the valve plug and the inner circumferential surface of the cage is The valve plug can be reliably prevented from vibrating within the cage by acting on the valve plug in one direction due to the fluid pressure difference caused by the above.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional cage valve, FIG. 2 is a cross-sectional view of a cage valve according to the present invention, and FIG. 3 is a cross-sectional view of FIG. 2. 1...Cage, 2...Peripheral wall, 3...Fluid passage window,
4, 5... Valve seat, 6... Valve plug, 8, 9... Seating part,
21...Eccentric groove.

Claims (1)

[Scope of Claims] 1. A cylindrical cage having a fluid passage window bored in a peripheral wall, valve seats provided above and below the window and having different diameters; A cage valve comprising a valve plug having seating portions that can be seated on both valve seats, wherein an eccentric groove is provided between the seating portions on the outer peripheral surface of the valve plug. . 2. The cage valve according to claim 1, wherein the eccentric groove is formed by casting with the same groove width over the entire circumference.