CN86201796U - Throttle silencer with multiple holes - Google Patents

Abstract

The utility model discloses a throttle silencer with multiple holes, belonging to a device which eliminates noise generated in the process of discharging gas (vapor). The utility model comprising a silencer pipe, a silencing plate with multiple holes, and a conic baffle plate works on the principle of throttling and pressure release, which means that when the gas (vapor) passes through the silencing plate and the conic baffle plate, part of the static pressure energy of the gas (vapor) flow is consumed to overcome the resistance force encountered by the gas flow on the silencing plate, the friction force between the gas flow, and the swirl of the gas flow, which is formed behind the silencing plate; as a result, the pressure and the flow rate of gas discharging are reduced, and the goal of eliminating noise is obtained. The throttle silencer with multiple holes is suitable for various situations in which noise is generated in the process of discharging gas (vapor).

Description

Throttle silencer with multiple holes

What the present invention relates to is the baffler that utilizes a kind of elimination gas (vapour) body displacement noise of throttling decompression principle design.

Existing baffler is the principle manufacturings such as absorption, reflection and interference according to sound, to reduce the noise of sound source radiation.Resistive trumpet type silencer is to paste sound absorbing material at the inner-walls of duct lining, and to reduce middle and high audio-frequency noise, sound deadening capacity depends on the sound-absorption coefficient of hush pipe length and sound absorbing material.The resistant noise-reducing device is to enlarge channel of acoustic wave earlier, dwindles again again, and to stop acoustic wave propagation, sound-damping qualities depends on divergence ratio.The interfering type baffler is that the passage with sound wave is divided into two, and a passage length is longer by 1/2 than another passage, and remerging two passages is a passage, and the effect that utilizes two sound waves to interfere with each other reaches the purpose of eliminating noise.

Resistive baffler inwall filling sound absorbing material, as glass wool, slag wool, porous fibre etc., these strengths of materials are poor, can be brought in the atmosphere by air-flow after use a period of time, cause atmospheric pollution, and erasure effect obviously descends simultaneously.Resistant noise-reducing device and interfering type baffler are made more complicated, cost height.

The purpose of this invention is to provide a kind of porous throttling baffler that utilizes the throttling decompression principle, as shown in Figure 1.(1) is muffler pipe among the figure, and (2) are the porous acoustical panel, and (3) are conical baffling plate.A-A is the sectional drawing of porous acoustical panel (2), and B is the unfolded drawing of taper deflection plate (3).When gas when the acoustical panel, a part of static energy of air-flow is consumed in and overcomes friction and the air-flow whirlpool that acoustical panel after form of air-flow between the resistance air-flow on the acoustical panel, thereby reduces the pressure of discharging gas and the speed of air-flow.

The design of baffler and calculating are according to fluid mechanics Bernoulli's law and fluid law of continuity, suppose that fluid is adiabatic process by the process of acoustical panel and deflection plate, can obtain following fundamental formular:

Q＝1.111αεβ ²D ² $\sqrt{\mathrm{△P/\gamma }}$ ┉（1）

In the formula: Q is the exhausting air volume, rice ³/ second;

D is the internal diameter of muffler pipe, rice;

△ P is that the pressure on the acoustical panel falls, handkerchief (Newton/meter ²);

γ is an exhausting air density under the working state, kilogram/rice ³

β is an equivalent perforate ratio, β=d/D;

D is a perforate equivalent diameter on acoustical panel or the deflection plate, rice;

α is a flow coefficient, α=f(β, Red);

Red is the reynolds' number that air communication is crossed baffler;

ε is a fluid stream compressibility coefficient ε=f(△ P/P, β, K);

K is the exhausting air isentropic exponent.

Obtain by (1) formula:

${\mathrm{a\; \epsilon \; \beta }}^2=\frac{Q}{{\mathrm{1.111\; D}}^2\sqrt{\mathrm{△\; P\; /\; \gamma }}}\mathrm{-----(\; 2\; )}$

According to " calculating of compressible medium restriction orifice " (periodical: oil-refining chemical automation, 1978.6) and " design of flow measurement differential pressure producer, installation and use " (GB GB-2624-81, Shanghai instrument and meter for automation research institute compiles, 1981) curve that provides, can be with α ε β ²Be organized into table 1 with the relation of △ P/P, K and β, as the foundation of calculating.Specifically:

(1) internal diameter of muffler pipe be the outlet pipe internal diameter 1.5-10 doubly.

(2) pressure reduction on acoustical panel and the deflection plate is than the critical pressure differential ratio that should be lower than all gases that table 2 provides.Fall calculating according to the pressure on total pressure drop and each acoustical panel, acoustical panel quantity is the 1-20 piece.

(3) distance between the acoustical panel is greater than 0.2 meter.

(4) the acoustical panel minimum thickness can fall with operating temperature according to the pressure before and after the acoustical panel and determine, generally between the 14-50.5 millimeter, concrete numerical value is referring to table 3.

(5) fall gas density γ under △ P, exhausting air flow Q and the working state according to the pressure before and after the muffler pipe inside diameter D, acoustical panel, can obtain α ε β by (2) formula ²Value can be found the equivalent perforate than the β value from table 1, by d=β D, can calculate perforate equivalent diameter d.

(6) the hole diameter d on acoustical panel perforate number N and the acoustical panel ₀, can be according to N=(d/d ₀) ²This relation is calculated.Hole diameter d on the general acoustical panel ₀Be the 1-60 millimeter, be preferably the 5-35 millimeter.The round numbers of perforate number N, it should be lower than the maximum perforate number N of following formula _Max

N _max＝0.907（ (D)/(d _O＋f _O) －0.94） ²

F in the formula ₀Be the distance between the little bore edges, millimeter.

(7) deflection plate be shaped as taper shape, cone angle can be selected arbitrarily, and is comparatively suitable with 120 ± 5 °.The thickness of deflection plate is the 2-5 millimeter, and the hole diameter on the deflection plate is greater than 1 millimeter.

Porous throttling baffler of the present invention, simple in structure, to make easily, cost is lower, and is easy to install, and the long life-span is arranged, and is adapted to be mounted within on the device and equipment that produces gas (vapour) body displacement noise.

Embodiment

For removing CO ₂Gaseous emission noise and design porous throttling baffler, CO ₂Gaseous emission pressure is 6 kilograms per centimeter ², discharge amount Q _MaxIt is 2500 meters ³/ hour, the discharge medium temperature is 35 ℃, the discharge pipe internal diameter is 0.067 meter.Inside diameter D according to the selected porous throttling baffler of the present invention of these data is 0.219 meter, and according to exhausting air pressure, the pressure reduction ratio before and after the acoustical panel should be less than the principle of critical pressure differential ratio, and the quantity that calculates required acoustical panel is 2.

Adopt a conical baffling plate, cone angle is 120 °, and calculate according to formula noted earlier in little number of perforations and aperture on acoustical panel and the deflection plate.

Carry out CO according to Fig. 2 ₂The gaseous emission test keeps the certain aperture of PCV-9 valve, closes V earlier ₁Valve is opened V ₂Valve makes CO ₂The direct emptying of air-flow records 104.5 decibels of noises.Close V then ₂Valve is opened V ₁Valve makes CO ₂All through the baffler discharging, record noise is 84 decibels to air-flow.

Test result shows, adopts porous throttling baffler of the present invention, can make original noise drop to the requirement (being lower than 90 decibels) of noise-less pollution.

Claims (4)

1, the baffler of a kind of elimination gas (vapour) body displacement noise is characterized in that a cylindrical muffler pipe [1], and an acoustical panel with holes [2] and a deflection plate [3] are equipped with in the inside.

2, baffler as claimed in claim 1, the internal diameter that it is characterized in that cylindrical muffler pipe are 1.5-10 times of exhausting air bore.

3, baffler as claimed in claim 1 is characterized in that: acoustical panel thickness is the 14-50.0 millimeter, and the quantity of acoustical panel is the 1-20 piece, between the acoustical panel distance greater than 0.2 meter, the hole diameter d on the acoustical panel ₀Be the 1-60 millimeter.

4, baffler as claimed in claim 1 is characterized in that the taper shape that is shaped as of deflection plate, and the hole diameter on the deflection plate is greater than 1 millimeter.

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