JPH0237515B2 - TEISOONCHOSETSUBEN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low noise control valve having a noise prevention function.

[Conventional technology]

Conventionally, this type of low-noise control valve has used cage-type valves with a large number of holes in the flow characteristic part, or multiple multi-hole throttles, in order to reduce the noise generated during use. There is.

[Problem that the invention seeks to solve]

However, in the case of the former, it was only possible to achieve an effect of reducing noise by at most 10 dB.

On the other hand, for the latter, large diameter valves (300mm or more)
In this case, it is necessary to drill thousands or more small holes of several millimeters or less due to the corrosion resistance of the stainless steel used, which has the disadvantage of increasing manufacturing costs.

[Means for solving problems]

The low noise control valve according to the present invention has a large number of annular plates arranged around a cage at intervals of about 4 mm in the axial direction, and the inner peripheral edges of these annular plates are formed into blade shapes.

[Effect]

In the present invention, among the noise that passes between the annular plates, the noise that is propagated parallel to the annular plates is due to the viscosity of the fluid, and the noise that is not propagated is reflected by the annular plates and is propagated until it reaches the exit side of the annular plates. Attenuate.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the structure etc. of the low noise control valve based on this invention will be explained in detail by the Example shown in the figure. Fig. 1 is a sectional view showing an embodiment of the low noise control valve according to the present invention, Fig. 2 is a sectional view showing the main parts of the low noise control valve, and Fig. 3 shows the state in which the annular plate is attached. FIG. In the figure, what is indicated by the reference numeral 1 is the valve main body, and internally there are formed compartments 3 and 4 which are vertically partitioned by a partition wall 2, and these compartments 4 and 3 are connected to an inlet 5 and an outlet 6, respectively. Yotsute valve body 1
It is open on both sides. Reference numeral 7 denotes a cylindrical cage that opens to the noise 4, and is disposed within the compartment 3, and has valve seats 8, 9 and a number of holes 10 on its peripheral wall.
is provided. Reference numerals 11 and 12 are annular mounting members having the same axis as the cage 7, and are located around the cage 7 and disposed within the compartment 3. Reference numeral 13 denotes a number of annular plates each having a blade-shaped inner peripheral edge, which are located between the mounting members 11 and 12 and spaced apart from each other by approximately 4 mm in the axial direction around the cage 7. . This annular plate 13 has a predetermined thickness t, that is, a thickness t that does not resonate due to the reflection of noise when fluid passes through it, and is formed with a sufficient width so that the lengths of the inner and outer circumferences are significantly different. There is. Numeral 14 is a rod for fixing these annular plates 13 by welding, and is inserted through the annular plates 13 and provided on the mounting members 11 and 12. Reference numeral 15 denotes a piston-type plug having seating portions 16 and 17 that can be brought into close contact with the valve seats 8 and 9, and is disposed inside the cage 7 so as to be movable up and down. In addition, the compartment 3
is also opened above the valve body 1 so that the cage 7, mounting members 11 and 12, and annular plate 13 can be inserted and removed. Two upper and lower lid members 18 and 19 are fixed to the valve body 1 and the lid member 18, respectively, to cover this opening, and the upper lid member 19 of these lid members 18 and 19 has a valve shaft 20. It is pivotally supported so that it can slide freely.

In the low-noise control valve configured in this way, when the piston-type plug 15 is raised by actuation of an actuator (not shown), the fluid flowing into the cage 7 from the inlet 5 as shown by the arrow in FIG. passes through the hole 10, passes between the annular plates 13 in a radial manner, and flows out to the outlet 6. At this time, among the noise waves that spread out from the exit of the hole 10 of the cage 7 and pass between the annular plates 13, as shown by the marks in FIG. depending on the viscosity of the annular plate 13.
As a result, the light is attenuated by the time it reaches the exit side of the annular plate 13. In this case, if the radial length L of the annular plates 13 is sufficiently long, the distance d between the annular plates 13 is d<λ (in practical terms, d<λ) for the wavelength λ of the noise wave.
λ/10, 10d≦L), but since there is not enough space inside the valve body 11, the length L
Noise can be suppressed by reducing the distance d instead of shortening the distance d.

Here, the interval d of the annular plate 13 is 4 mm because the frequency f of the aerodynamic noise of the valve is usually 1000 to 8000 Hz, and the propagation speed v of the sound in normal air is 340 m/s, so λ=
From v/f, minimum wavelength λ = 340/8000 = 0.043m ≒ 4
It can be found that cm<L.

Although this embodiment shows an example in which the annular plate 13 is fixed to the rod 14 at a distance d, the present invention is not limited to this, and as shown in FIGS. Considering the surface, ribs 21a and bosses 22a are provided on the annular plates 21 and 22, respectively,
Of course, the annular plates 21 and 22 may be fixed to these by electric resistance welding.

〔Effect of the invention〕

As explained above, according to the present invention, a large number of annular plates are arranged around the cage at intervals of approximately 4 mm in the axial direction, and the inner peripheral edges of these annular plates are formed into blade shapes. Of the noise that passes between the plates, the noise that is propagated parallel to the annular plate is due to the viscosity of the fluid, and the noise that is not propagated is reflected by the annular plate, so that it is ensured that it is attenuated by the time it reaches the exit side of the annular plate. Therefore, the noise suppression effect can be greatly improved. In addition, since countless small holes are not drilled in a corrosion-resistant material such as stainless steel as in the past, manufacturing costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the low noise control valve according to the present invention, Fig. 2 is a sectional view showing the main parts of the low noise control valve, and Fig. 3 shows the state in which the annular plate is attached. FIG. 4 is a sectional view for explaining the propagation state of noise waves, and FIGS. 5 and 6 are perspective views showing annular plates in other embodiments. 1... Valve body, 7... Cage, 10... Hole, 1
3... Annular plate, 14... Rod, 15... Piston type plug.

Claims (1)

[Claims] 1. A low-rise device characterized in that a large number of annular plates are arranged at intervals of approximately 4 mm in the axial direction around a cage having a large number of holes in the peripheral wall, and the inner peripheral edges of these annular plates are formed into a blade shape. Noise control valve.