JPH0143875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a low-noise valve having a structure that reduces noise generated by fluid pressure reduction, high-speed fluid flow, and the like.

[Prior art]

In general, when a valve provides resistance to the flow of fluid, undesirable noise may be generated due to flow turbulence occurring at the throttle portion of the valve. 1st
The figure is a vertical cross-sectional view of a conventional cage valve shown to explain this noise generation. To explain this based on the figure, the valve body 1 has an upstream passage 3 and a downstream side separated by a partition wall 2. A cylindrical cage 7 and a seat ring 8 are disposed between the partition wall 2 and the top cover 6, which is fitted into the upper opening end of the top cover 6 and fixed with bolts 5. ,10
It is fitted through. On the peripheral wall of cage 7,
A plurality of windows 11 are opened to communicate the inside of the cage 7 and the upstream channel 3, and the windows 11 are formed into a substantially T-shape with a wide part and a narrow part. Further, a lower open end of the seat ring 8 is opened to the downstream flow path 4 . A valve rod 1 is slidably inserted into the inner hole of the cage 7 through the upper lid 6 via a gasket 12.
3. A valve plug 14 at the lower end of the valve plug 14 is slidably fitted therein, and an underwear seat is provided at the lower end of the valve plug 14 to sit on a valve seat 15 provided at the upper end opening of the seat ring 8 when the seat ring 8 is fully closed. A section 16 is provided.
Further, an upper seating portion 18 is provided on the outer peripheral portion of the upper end of the valve plug 14 to sit on a valve seat 17 formed on the inner peripheral surface of the cage 7 .

With this configuration, when the valve stem 13 is moved up and down by the actuation of the drive unit by the automatic control device or by manual operation, the valve plug 14 moves together with the valve stem 13 to adjust the opening degree of the window 11. That is, the opening area changes, thereby controlling the flow rate of the controlled fluid flowing from the upstream flow path 3 through the window 11 of the cage 7 and the seat ring 8 to the downstream flow path 4.

In the flow rate control using the cage valve as described above, when fluid flows from the window 11 downward to the valve plug 14 while being depressurized as shown by the arrow, the inflowing fluid entrains the surrounding fluid, causing turbulent flow. Strong noise is generated due to the high frequency.
Furthermore, this noise also propagates to the downstream piping section, so there is a drawback that it leaks outside and aggravates the situation.

Therefore, in the past, Japanese Patent Application No. 51-040930,
No. 050614, etc., fills spheres in both the upstream and downstream channels 3 and 4, inside the valve plug 14, in the cylindrical housing provided below the seat ring 8, etc., and reduces the sound by reducing the energy flowing through it. has been proposed, and it has also been proposed to further improve the silencing effect by changing the sphere diameter in the direction of fluid flow, but in both cases, the fluid flow tends to be biased toward the center of the flow path, which reduces noise. passes through the valve, so a satisfactory silencing effect cannot be expected, and if the silencing section is unavoidably lengthened in order to increase the silencing effect, the valve as a whole becomes larger. In addition, various low-noise valves other than those provided with spheres have been proposed, but no effective results have been obtained with any of them.

[Summary of the invention]

The present invention has been made in view of the above points, and includes forming a flow path on the downstream side of a valve body substantially concentrically with a cylindrical cage, and providing a multi-stage porous partition plate that crosses this flow path. In order to eliminate noise, a plurality of noise-absorbing packing bodies are filled between each partition plate to form a gap for fluid to pass between them, and by setting the size and shape of these packing bodies, the gap for fluid to pass through can be set as a flow path. The present invention provides a low-noise valve that is configured to be small at the center of the flow path and large at the outer periphery of the flow path, thereby allowing fluid to pass through the flow path without being biased towards the center of the flow path, thereby improving the silencing effect. . Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

FIG. 2 is a longitudinal sectional view showing an embodiment of the low noise valve according to the present invention. In the figure, the valve body 22 of the low-noise valve 21 is provided with an upstream passage 23 that opens horizontally and is flanged to the upstream pipe line, and the upward opening of the valve body 22 includes: The upper cover 24 is joined and fixed with bolts 25 and nuts 26. A cage 27 is formed into a cylindrical shape and is fitted inside the valve body 22 below the upper lid 24. A gasket 28 is inserted between the cage 27 and the upper lid 24. Fixed. A plurality of windows 2 are provided on the peripheral wall of the cage 27.
9 is opened, and this window 29 allows communication between the upstream passage 23 surrounding the cage 27 and the inside of the cage 27. A valve stem 31 is screwed into a cylindrical valve plug 30 that is slidably fitted into the inner hole of the cage 27, and this valve stem 31 is inserted into the upper lid 24 through a packing 32 in the packing box 21. It is pivoted. Reference numeral 33 denotes a packing holder that presses the packing 32 toward the stepped portion of the upper lid 24. Also 34,3
Reference numerals 5 designate upper and lower seat portions provided at the upper and lower portions of the valve plug 30 and seated on the valve seats 36 and 37 on the cage 27 side, respectively. and valve plug 30
When the cage 27 is raised or lowered, the degree of opening of the window 29 changes, and the flow rate of fluid flowing from the upstream channel 23 through the window 29 into the cage 27 is adjusted.

The valve body 22 has a downstream flow path 38 formed substantially perpendicular to the upstream flow path 23 and concentrically with the cage 27.
The lower end flange portion is connected to the downstream pipe line. This downstream flow path 38 is formed in the shape of a truncated cone whose diameter gradually increases in the direction of fluid flow, and connects the cage 27 to the cage 27 through a hole in a perforated plate 39 attached to the lower end opening of the cage 27. communicated with the inside. The downstream flow path 38 is partitioned into a plurality of chambers by multiple stages (three stages in this example) of porous partition plates 40, 41, and 42 having a large number of holes welded to the inner peripheral wall thereof. Each inner chamber is closely filled with steel balls 43 and 44, which are shown as an example of a noise-reducing filler with a fluid passage gap formed therebetween. And steel ball 43 is steel ball 44
The steel balls 44 are formed to have a larger diameter and are filled in the entire inner chamber of the top tier and the outer periphery of the chambers in the second and lower tiers, and the smaller diameter steel balls 44 are filled in the center of the inner chambers in the second and lower tiers. has been done. 45 is the steel ball 43 filling part and the steel ball 44
This is an annular partition net that separates the filling part from the filling part. By setting the diameters of the steel balls 43 and 44 in this manner, the total volume of the gaps between the steel balls is small at the center of the downstream flow path 38 and large at the outer periphery. Therefore, it is easier for fluid to pass through the outer periphery than the center.

The operation of the low noise valve configured as above will be explained. When the valve stem 31 is moved up and down by the actuation of the drive unit by an automatic control device or by manual operation, the valve plug 30 moves together with the valve plug 30, and the opening degree, that is, the opening area of the window 29 changes. Thus, the flow rate of the fluid flowing from the upstream flow path 23 to the downstream flow path 38 through the window 29 of the cage 27 is controlled. In the downstream flow path 38, the fluid flows through gaps between the steel balls 43 and between the steel balls 44.

When the fluid continues to flow from the upstream flow path 23 to the downstream flow path 38 while the flow rate is controlled in this way, the fluid flowing in from the window 29 while being depressurized entrains the surrounding fluid and becomes turbulent. As a result, high-frequency noise is generated. This noise tries to propagate to the outside through the downstream flow path 38, but since the inner chamber of the downstream flow path 38 is filled with a large number of steel balls 43, 44, the fluid is depressurized in multiple stages. However, the noise disappears while flowing through the gap between the steel balls 43 and 44, and is not propagated to the outside. In this case, the fluid flow usually tends to be biased toward the center of the flow path 38, but in this device, the steel balls 44 at the center are replaced by the steel balls 44 at the outer periphery.
Since the diameter of the steel balls is smaller than that of 3 and the gap between the steel balls is small in the center, the fluid flow is directed to the flow path 38.
The silencing effect is further increased, and there is no need to increase the length of the flow path 38 in order to improve the silencing effect in the center.

FIG. 3 is a perspective view of a sound-deadening filling body showing another embodiment of the present invention, and in this embodiment, the steel balls 43 of the previous embodiment, In place of 44, use the short and small tube piece 4 shown in the figure.
It was set at 6. This tube piece 46 is made by cutting a stainless steel pipe into small pieces, and when filled with it, a gap is formed between them for fluid to pass between them, similar to a steel ball, so it has a fluid flowing function and a noise damping effect, and also has a hollow Since it is made of steel, its weight is significantly reduced compared to steel balls, making the entire valve lighter.

Note that the partition steel 45 does not necessarily need to be provided, and it is sufficient to fill it with large and small filling bodies such that the small ones are distributed approximately at the center of the flow path 38.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, in a low-noise valve, the flow path on the downstream side of the valve body is formed substantially concentrically with the cylindrical cage, and a plurality of stages are formed across the flow path. A porous partition plate is provided, and each partition plate is filled with a plurality of sound-deadening fillers that form gaps for fluid to pass between them, and by setting the size and shape of the fillers, the gap for fluid to pass is formed into a flow path. By configuring the cage to be small at the center and large at the outer periphery of the channel, even if noise is generated when fluid flows from the upstream channel through the window of the cage to the downstream channel, the fluid While flowing in a zigzag pattern through the gaps between the filling bodies, the pressure is reduced in multiple stages, reducing the energy of the flow, eliminating noise and preventing it from propagating to the outside of the valve, resulting in quiet operation. and the environment will be improved. In addition, the fluid flow, which tends to be biased towards the center of the channel, is dispersed to the outer periphery of the channel where there is a large passage gap and is made uniform throughout the channel, further increasing the noise reduction effect and increasing the There is no need to increase the length of the flow path in order to improve the silencing effect, and the entire valve can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a conventional low-noise valve, FIGS. 2 and 3 are examples of a low-noise valve according to the present invention, FIG. 2 is a vertical cross-sectional view thereof, and FIG. 3 is a vertical cross-sectional view of the present invention. It is a perspective view of the filling body for sound deadening which shows another Example. 21...Low noise valve, 27...Cage, 29...
Window, 38... Downstream channel, 40, 41, 42...
Porous partition plate, 43, 44... steel ball, 46... tube body.

Claims (1)

[Claims] 1. A downstream flow path of the valve body through which the fluid flowing in from the peripheral wall opening of the cylindrical cage passes toward the downstream pipe path is formed substantially concentrically with the cage, and a plurality of stages are formed to cross this flow path. A porous partition plate is provided, and a plurality of sound-deadening fillers are filled between each partition plate to form a gap for fluid to pass between them, and the gap is small at the center of the flow path and is located at the outer periphery of the flow path. 1. A low-noise valve, characterized in that the shape and dimensions of the sound-deadening filling body are set such that it becomes larger in the middle.