JPS6199785A - Low-noise adjusting valve - Google Patents

Abstract

PURPOSE:To improve the noise suppressing effect by arranging a plurality of annular plates whose inner peripheral edge is formed into blade form onto the periphery of a cage having a number of holes on the peripheral wall, keeping an interval in the axial direction. CONSTITUTION:Valve seats 8 and 9 and a number of holes 10 are installed onto the peripheral wall of a cylindrical cage 7 which is opened to a compartment chamber 4. A number of annular plates 13 whose inner peripheral edge is formed into blade form are arranged, keeping an interval of 4mm in the direction of axis line onto the periphery of the cage 7. Among the noise waves which spread in trumpet form from the outlet of the hole 10 on the cage 7 and pass between the annular plates 13, the noise waves which are spread in parallel to the annular plates 13 are attenuated by the viscosity of fluid, and the noise waves which are not transmitted in parallel to the annular plates 13 are attenuated in the course to the outlet side of the annular plate 13 by the reflection on the annular plates 13.

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, in the case of the latter, in the case of large-diameter valves (300 tm or more), the corrosion-resistant material such as stainless steel used for this valve has several nanometers.
It is necessary to drill dozens or more of the following small holes, which is disadvantageous in that the production cost increases.

[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 squares in the axial direction, and the inner peripheral edges of these annular plates are formed into blade shapes. .

[For production]

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, the reference numeral 1 indicates the valve body, and inside thereof there are formed compartments 3.4 which are partitioned into upper and lower parts by a partition wall 2, and these compartments 4 and 3 each have a population of 5.5. The outlet 6 opens on both sides of the valve body l. Reference numeral 7 denotes a cylindrical cage opening into the compartment 4, which is disposed within the compartment 3, and has valve seats 8, 9 and a number of holes 10 provided in its peripheral wall. 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 are arranged around the cage 7 at intervals of approximately 4 fl in the axial direction. . 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 the fluid passes through the annular plate 13, and is formed with a sufficient width so that the lengths of the inner and outer circumferences are significantly different. 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 member 11.12. 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. Further, the compartment 3 is also opened above the valve body 1 so that the cage 7, the mounting members 11 and 12, and the annular plate 13 can be inserted and removed. Two upper and lower lid members 18 and 19 are provided to cover this opening, respectively. The upper lid member 19 of these lid members 18 and 19 has a valve shaft 2.
0 is slidably supported.

In the low noise control valve configured in this way, the piston type plug 1 is operated by an actuator (not shown).
5 is raised, the fluid that has flowed into the cage 7 from the inlet 5 flows through the hole IO, passes radially between the annular plates 13, and flows out to the outlet 6, as shown by the arrow in FIG. At this time, among the noise waves that spread in a rubber shape from the exit of the hole 10 of the cage 7 and pass between the annular plates 13 as shown by the arrow in FIG. Otherwise, it is reflected by the annular plate 13 and is attenuated by the time it reaches the exit side of the annular plate 13.

In this case, if the length of the annular plates 13 in the radial direction is sufficiently long, the distance d between the annular plates 13 will be d and λ(
Practically speaking, it is sufficient to satisfy the relationship d×λ/10.10d≦L), but since there is not enough space within the valve body,
Noise can be suppressed by reducing the distance d instead of shortening the length.

Here, the interval d of the annular plate 13 is 4B, and the frequency f of the aerodynamic noise of the valve is usually 1000 to 8000 Hz.

Since the sound propagation velocity V of normal temperature air is 340 m/s,
From λ=v/f, minimum wavelength λ=340/8000=
It can be found that 0.043rn'q4cm<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 are provided on the annular plates 21 and 22, respectively.
Of course, bosses 22a may be provided and annular plates 21, 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 41 m 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 the drawing]

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, 13... Annular plate, 14... Rod, 15...
Piston type plug.

Claims (1)

[Claims] A low-noise 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. Control valve.