JPS61266877A - Adjusting valve - Google Patents

Abstract

PURPOSE:To aim at reducing noise and to prevent the generation of cavitation, by arranging a noise preventing material on the outer peripheral surface of a cage. CONSTITUTION:Several small holes 12 are formed in the lower section of a cage 8. Further, several noise preventing materials 13 are wrapped around the outer peripheral surface of the cage 8. With this arrangement fluid is deflected from the inside to the outside of the cage 8 while it flows through the small holes 12 through which a pressure loss is effected. Further, several jet streams emerged from the small holes 12 in the cage 8 are driven through the gaps in the noise preventing materials 13, thereby it is possible to prevent the generation of cavitation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control valve for regulating the pressure and flow rate of fluid.

[Conventional technology]

As a prior art of this kind, Japanese Patent Application Laid-Open No. 59-175687
Publication No.

To explain this structure, a cylindrical cage with a large number of small holes is placed in the valve chamber of the casing (= a cylindrical cage with many small holes on the outer circumferential surface), and the fluid that has passed through the constriction between the valve body and the valve seat is passed through the cage. The structure is configured so that the fluid (gas, liquid, etc.) passes through the small hole and then flows out, and by passing the fluid (gas, liquid, etc.) through the small hole, a large pressure loss is obtained, and the loss pressure is transferred to the constriction section between the valve body and the valve seat. This acts as a back pressure to reduce the fluid pressure difference at the constriction part, reduce wear and noise on the contact surface between the valve body and valve seat, and prevent cavitation and double lotion.

Generally, as shown in FIG. 6, the structure of a supersonic jet ejected from a hole (a) is divided into a mixing region (b) and a turbulent region (C).

A supersonic region exists in the mixing region near the hole exit, and shock waves (
d) occurs.

In addition, strong mixing with the surrounding gas occurs within the shear layer in this region.

On the other hand, in the turbulent region, the supersonic region disappears, and the jet becomes a turbulent flow accompanied by large-scale eddies over the entire radius.

The noise characteristics of this jet flow are largely controlled by the characteristics of the turbulent field in the mixing zone near the hole, and mainly depend on the shear strength.

The low noise effect of conventional porous structures has been achieved by making the length of the mixing zone as small as possible, and by adjusting the spacing between the holes to obtain proper interference of the individual jets.

[Problem that the invention seeks to solve]

However, in the conventional structure 2, when the noise reduction effect is improved, the pressure loss in the porous part increases, making it impractical.
Furthermore, since it is essentially impossible to prevent the generation of shock waves, it has the disadvantage that very low noise cannot be expected.

[Means for solving problems]

The purpose of the present invention is to eliminate these inconveniences.The gist of the present invention is to arrange a cylindrical cage with a large number of small holes on the outer circumferential surface in the valve chamber of the casing, and to connect the valve body and valve seat. In the control valve, the fluid passing through the constriction part between the cages flows from the inside of the cage to the outside of the cage through the large number of small holes. The control valve is characterized in that it is constructed by surrounding a noise prevention member.

[For production]

The fluid flows out from the inside of the cage to the outside through the small holes in the cage, forming a large number of jets, but the noise is caused by the effects of rectification, mixing, and diffusion as the insects pass through the gaps in the noise prevention member. In addition, it quickly mixes and diffuses the individual jets to make them uniform, reducing the flow velocity to the level of the turbulent region, and as a result, noise, especially generated from the cage part. Reduces noise and suppresses cavitation when using liquids.

〔Example〕

1 to 6 show embodiments of the control valve to which the present invention is applied, and FIGS. 1 to 3 show the first embodiment, FIG. 4 shows the second embodiment, FIG. 5 shows the third embodiment, FIG. 6 shows a structural diagram of a supersonic jet ejected from a small hole in the cage.

In the first embodiment shown in FIGS. 1 to 3, (1) is a casing, which includes an inlet channel (2) and an outlet channel (2).
3) is formed, a lid body (4) is fixed to the upper part with bolts (5), and a valve chamber (6) is formed at the mutual intersection of the inlet channel (2) and the outlet channel (3). is formed.

A valve seat (7) is fixed to the lower part of the valve chamber (6).
) A cylindrical cage (8) is fixed inside the cage (8).
) is provided with a valve body (9) slidable up and down, and the inner circumferential surface of the cage (8) and the outer circumferential surface of the valve body (9) are in sliding contact.
A valve stem σO) is connected to the upper part of the valve body (9).
A throttle side is formed between the lower end surface and the valve seat (7).

There are many small holes a2 at the bottom of the cage (8).
is formed in the radial direction.

(1~ are noise prevention members, in this case stainless steel wire meshes, which are wrapped around the outer circumferential surface of the cage (8), and the gaps between the wire meshes are defined as a group of gaps (14).

Since this $1 embodiment has the above configuration, when the valve body (9) is raised by the valve stem α■, the constriction part (1υ) opens, and the fluid flows from the inlet flow path (2) through the constriction part αυ to the cage ( 8) It reaches the inside and flows out from the inside of the cage (8) through a large number of small holes, causing changes in the area of the throttle part αυ and the valve body (
The flow rate and pressure are adjusted according to the opening area of the small hole (13), which changes depending on the amount of movement of the small hole (13), and the liquid flows out from the outlet channel (3).

In this case, the fluid passes through the small holes (13) while being diverted from the inside of the cage (8) to the outside, causing a pressure loss due to the small holes α.

In addition, in the process of passing through the gap group I of the noise prevention member, the large number of jets flowing out through the small holes CI of the cage (8) interfere with the flow path wall of the gap group a4, causing shock waves to be generated. suppress.

Furthermore, due to the effective rectification mixing and diffusion effect during this time, the flow after passing through the noise prevention member α4 can be made uniform, and the flow velocity can be reduced to the level of the turbulent region (C).

As a result, it is possible to reduce noise, particularly noise from the cage portion, and to suppress the occurrence of cavitation when using liquid.

In particular, since the noise prevention member (131) is composed of several wire meshes wrapped around each other, its structure (therefore, the noise prevention member (131) has effective mixing and diffusion without friction loss and directionality due to the gap group side). Effect can be obtained.

In the second embodiment shown in FIG. 4, a plurality of large diameter and small diameter cylindrical cages (8) are formed, these are arranged inside and outside, and a noise prevention member (13) is interposed between them. Further, in the third embodiment shown in FIG. 5, the noise prevention member Q4 is formed of a porous member, such as ceramic, and the pores are used as the gap group (14). .

In this case (= also, the generation of noise etc. can be prevented as in the first embodiment. In addition, since it is difficult to manufacture the small holes of the cage (8),
8) may be divided into upper and lower layers, and a small hole U may be obtained by opposing grooves.

〔Effect of the invention〕

As described above, in the present invention, the fluid that passes through the small holes from the inside of the cage to the outside flows out through the gaps in the noise prevention member, and as a result, it is possible to significantly reduce noise in the gauge section. Not only can this be achieved, but it can also prevent the occurrence of cavitation, etc.

As described above, the intended purpose can be fully achieved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a longitudinal section of the first embodiment, FIG. 2 is a plan sectional view thereof, FIG. 3 is a partial sectional view thereof, and FIG. 4 is a second embodiment. FIG. 5 is a partial sectional view of the third embodiment, and FIG. 6 is a structural diagram of a supersonic jet ejected from a small hole. (1)...Casing, (6)...Valve chamber, (7)...Valve seat, (8)...Cage, (9)...Valve body, αυ...Aperture, uka...Small hole , α~... Noise prevention member, (14)
-Gap group. May 20, 1985 Applicant 24N! -Mason←Inventor of Ran Co., Ltd. 1) Kiyoshi Shima (Kara 7/See 7z seat v4J 7th

Claims (1)

[Claims] A cylindrical cage with a large number of small holes on the outer circumferential surface is arranged inside the valve chamber of the casing, and the fluid that has passed through the constriction between the valve body and the valve seat is passed through the large number of small holes from inside the cage. In the control valve configured to allow the flow to flow out of the cage through the
A control valve characterized in that a noise prevention member having a large number of gap groups is provided around the outer peripheral surface of the cage.