JPH0648070B2 - Valve device - Google Patents

Description

The present invention relates to a low noise type valve device.

[Prior Art] Generally, in a valve device, when a resistance is applied to a flow of a fluid, undesired noise may be generated due to the turbulence of the flow generated in the throttle portion of the valve. Therefore, various valve devices that prevent, reduce, or absorb the generation of noise have been conventionally proposed. FIG. 4 is a sectional view showing a conventional example of such a low noise type valve device. The figure shows a high-pressure gas pressure reducing valve, 1 is a basket-type valve body whose inner center is partitioned by a partition wall 2 and 3 is a cylindrical valve seat fixed on the partition 2 of the valve body 1. A circulation hole 3A is formed in a part of the lower portion of the peripheral surface of the valve seat 3. Reference numeral 4 denotes a lid for closing the upper opening of the valve body 1 and fixing the valve seat 3 on the partition wall portion 5, reference numeral 5 denotes a cylindrical valve plug slidably fitted in the valve seat 3, and 6 denotes A valve shaft 8 which is inserted through a central hole of the lid 4 through a packing 7 to move the valve plug 5 up and down, and 8 is a diffuser. The diffuser 8 is formed into a cylindrical body having a large number of small holes 9 to restrict the flow. It is arranged on the downstream side, that is, below the valve seat 3.

In such a structure, the fluid flows in through the right opening 1A of the valve body 1 as shown by an arrow A in the drawing, and the fluid is formed in the flow hole 3A of the valve seat 3 and the peripheral surface of the lower end portion of the valve plug 5. Although it flows out to the left opening 1B through the hole 10 and the hole 11 formed in the center of the partition wall 2, the fluid is depressurized into the valve seat 3 from the flow hole 3A of the valve seat 3. In the case of inflow, as shown in the figure, a portion of the potential core 12 in which the flow velocity is the same as that of the inflowing fluid, and the mixing region 1 where the fluid is entrained around the potential core 12 and becomes a turbulent flow.
3 occurs. This mixing region 13 generates strong noise at a high frequency, and the noise is transmitted to the downstream pipe portion and leaks to the outside. Therefore, if the diffuser 8 is provided on the downstream side of the flow restricting portion, the pressure is reduced when the fluid passes through the small holes 9 to prevent the generation of noise.

[Problems to be Solved by the Invention] However, in such a conventional valve device, the diffuser 8 is not designed by performing acoustical examination, and is recognized as a kind of resistance element. However, the design is limited to the flow rate characteristics, and the noise level is only secondarily reduced to some extent, which is insufficient as a low noise valve.

Further, regarding the noise generated when the fluid passes through the small holes 9 of the diffuser 8, no measures have been taken to attenuate or absorb the noise, and there is a drawback that the noise is propagated to the secondary side pipe. It was

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to significantly reduce and absorb the noise generated on the downstream side of the throttle portion. To provide.

[Means for Solving the Problems] In order to achieve the above object, the present invention relates to a valve device for controlling a flow rate by advancing / retreating movement of a valve plug facing a through hole, and a cylinder having an inner peripheral surface formed into an elliptic curved surface. A sound absorbing cylinder is installed on the downstream side of the flow hole so that the two focal points of the sound absorbing cylinder are aligned in the flow direction of the fluid, and the upstream focus of the sound absorbing cylinder is substantially aligned with the center. A hemispherical shell member having small holes is arranged in the sound absorbing cylinder, and the sound absorbing member is arranged in the vicinity of the focus position on the downstream side of the sound absorbing cylinder.

[Operation] In the present invention, when the fluid passes through the small holes of the hemispherical shell member, jet noise is generated around the center of the shell member.
The jet noise spreads radially, hits the elliptical inner peripheral surface of the sound absorbing cylinder, is reflected, and is converged, attenuated and absorbed by the sound absorbing member disposed near the focus on the downstream side of the sound absorbing cylinder.

[Examples] The present invention will be described in detail below based on the examples shown in the drawings.

FIG. 1 is a sectional view showing an embodiment in which the valve device according to the present invention is applied to a cage type valve device, and FIG. 2 is an enlarged sectional view of a main part. In these figures, 20 is opened at the upper and lower sides and the middle portion in the height direction of one side surface. In the valve body of the above, a cylindrical valve seat 23 having a flow hole 22 formed in the peripheral surface of the lower end is fitted in the upper end opening 21, and the side opening 24 forms the upstream opening, and the lower end opening 25 forms the downstream opening. A valve shaft 26 is provided inside the valve seat 23.
A valve plug 27 that is moved up and down by is slidably fitted. Reference numeral 28 denotes a cylindrical sound absorbing cylinder whose upper end is joined to the lower end of the valve seat 23 and is arranged coaxially with the valve seat 23 on the downstream side of the throttle portion 29. The inner peripheral surface of the sound absorbing cylinder 28 is formed into an elliptical shape. The two focal points Q ₁ arranged in the fluid flow direction,
Q ₂ and has a hemispherical shell member 32 in the upper end opening 31.
Are fitted and arranged, and a sound absorbing member 33 is arranged on the lower side of the inside through a holding member 34.

The shell member 32 has a cylindrical shape in which the outer peripheral surface of the upper end fits into the inner peripheral surface of the upper end opening 31 of the sound absorbing cylinder 28, and is formed in a hemispherical shape so that the lower end side is convex toward the sound absorbing cylinder 28. The center of the hemisphere 32A substantially coincides with the upstream focus Q ₁ ,
In addition, a large number of small holes 35 are radially formed around the center of the hemisphere 32A.

The sound absorbing member 33 is made of a metal brush or the like,
8 is located in the vicinity of the downstream focal point Q ₂ , and is provided in a conical recess 36 provided in the central portion of the holding member 34.

The holding member 34 is formed in the shape of a ring, and the sound absorbing cylinder 2
A plurality of through holes 37, which are fitted and fixed to the inner peripheral surface of the lower end of 8, and are partitioned by ribs (not shown) between the central portion and the outer peripheral portion where the sound absorbing member 33 is disposed. Are formed.

Regarding the arrangement structure of the sound absorbing member 33, instead of disposing it in the recess 33 provided in the central portion of the holding member 34, it is placed on the central portion of the upper surface of the holding member 34 as shown in FIG. It may be covered by the porous member 38.

In such a configuration, the fluid flows from the upstream opening 24 of the valve body 20 to the flow hole 22 of the valve seat 23 and the shell member 32.
When flowing into the sound absorbing cylinder 28 through the small hole 35, acoustic waves are generated due to shearing of the flow of the throttle portion 29 of the valve, and jet noise is generated at the outlet of the small hole 35. As shown in FIG. 2, these acoustic waves and jet noises are multiplied by the flow of the fluid, and the center of the shell member 32, that is, the upstream focus Q of the sound absorbing cylinder 28.
₁ spreads radially around ₁ into the sound absorbing cylinder 28 through the small hole 35, hits the elliptical inner peripheral surface and is reflected, and is converged to the downstream focus Q ₂ , and when hitting the sound absorbing member 33, most of it is not attenuated or attenuated. It is absorbed and converted to heat.

That is, the present invention utilizes the elliptical inner peripheral surface 30 of the sound absorbing cylinder 28 to reduce the noise generated on the downstream side of the throttle portion 29 on the downstream side focus Q _2.
The result is that the noise absorption effect is great and the noise is hardly propagated to the downstream side pipeline, and the noise reduction can be achieved.

On the other hand, the fluid flowing into the sound absorbing cylinder 28 through the small hole 35 of the shell member 32 is discharged to the downstream side of the valve body 20 through the flow hole 37 of the holding member 34.

[Effects of the Invention] As described above, in the valve device according to the present invention, the sound absorbing cylinder having the elliptical inner peripheral surface and having two focal points is incorporated into the valve main body, and the center is located at the upstream focal position. Since the shell member having radial small holes around the center is arranged and the sound absorbing member is arranged near the focus on the downstream side, the noise generated at the downstream side of the throttle portion is reduced to the inner peripheral surface of the sound absorbing cylinder. It can be reflected by and focused on the downstream focus. Therefore, this noise hits the sound absorbing member and is effectively attenuated and absorbed, and the noise reduction of the valve device can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment in which the valve device according to the present invention is applied to a cage type valve device, FIG. 2 is a sectional view of a sound absorbing cylinder, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view of the main part shown, and FIG. 4 is a cross-sectional view of a conventional valve device. 20 ... Valve body, 22 ... Flow hole, 23 ... Valve seat, 27 ... Valve plug, 28 ... Sound absorbing cylinder, 32 ... Shell member, 33 ... Sound absorbing member,
34: holding member, 35: small hole, Q ₁ ... ellipse upstream focus, Q ₂ ... ellipse downstream focus.

Claims (1)

[Claims] 1. A valve device for controlling a flow rate by advancing / retreating a valve plug facing a flow hole, wherein a cylindrical sound absorbing cylinder having an inner peripheral surface formed into an elliptic curved surface, two focal points of which are a fluid flow direction. The sound absorbing cylinder has a hemispherical shell member in which a plurality of small holes are radially formed from the center of the sound absorbing cylinder so that the upstream focus and the upstream focus of the sound absorbing cylinder are substantially aligned with each other. A valve device, wherein a sound absorbing member is provided inside the sound absorbing cylinder and near a downstream focal position of the sound absorbing cylinder.