CN86104117B - Frequency modulation type exhausting gas flow stabilizing device - Google Patents

Abstract

The present invention relates to a frequency modulation type gas exhausting and flow stabilizing device which belongs to a gas flow silencer or a gas exhausting device of an ordinary machine or an engine. The device is composed of an outer pipe, an inner pipe, a contraction-expansion pipe, a frequency modulation conduit and a transmission component, wherein the frequency modulation conduit is used for modulating the length difference of a central passage and a spiral passage and the size of changing interference frequency for achieving the optimal interference effect; the frequency modulation conduit is connected with the contraction-expansion pipe for use to enhance a flow stabilizing effect. The frequency modulation type gas exhausting and flow stabilizing device is used for the engine and especially for volume type compressor equipment.

Description

FREQUENCY MODULATING EXHAUST SILENCER

The present invention relates to a kind of air exhaust muffler device with frequency modulation, it belongs to the silencer for gas flow or the venting gas appliance of general machine or motor.

A kind of having of causing for periodic fluctuation pressure of the common generation of the blast air of gas compressor, motor, particularly positive-displacement compressor transferred noise and the mixed noise of another kind for the turbulence noise of stream swirl generation.Wherein turbulence noise is the broadband random noise, and frequency spectrum is the broadband continuous spectrum, and its amplitude is less, and exhaust airstream pulse and noise are not played a major role.And the accent noise is wherein arranged, and on frequency spectrum, except that fundamental frequency, also have some to become the higher harmonics composition of integral multiple with fundamental frequency, being called has the accent noise.Its energy is bigger, concentrates on again on the limited frequency peak, and amplitude is very big usually, and they have determined the total amplitude of exhaust sound dynamic characteristic, and its frequency spectrum shows as one group of bar-shaped discrete line spectrum.The exhaust sound of positive-displacement compressor is normally planted the stack of noise like this, is that the accent noise is arranged owing to what play a decisive role in the exhaust sound, so reduce the fundamental component of transferring in the noise is arranged, and just becomes the major technique approach of such machine exhausting silencer.

Muffler shown in European patent EP-A-0184060 and Japan Patent spy drive the spirality baffler shown in the clear 57-191409, all adopt the interior pipe and the outer tube of coaxial line configuration, connect with helical baffle therebetween and the formation spirality channel, intersection interferes in the downstream to make in this passage in the air-flow and interior pipe air-flow, reaches the purpose of noise elimination.But its interference frequencies all is uncontrollable.Because the wave length of sound that changes such as delivery temperature, pressure, working medium constant cause changes and the change of the gas frequency that the operating conditions variation causes, it is accurately consistent that the required interference frequencies of Design Theory and practical application is difficult to, can not frequency modulation just often make on-the-spot interfere lost efficacy or interference effect relatively poor, can't guarantee the requirement of interfering fully.

For solving the above problems, the invention provides a kind of interference frequencies of regulating continuously at the scene and interfere to reach fully, effectively reduce the air exhaust muffler device that the fluctuation pressure of transferring noise is arranged.

Structure of the present invention comprises the interior pipe of coaxial line configuration and the outer tube of its two ends band adpting flange, be provided with helical baffle between outer tube and the interior pipe, this dividing plate and outer tube wall and outer wall of inner tube constitute spirality channel, have perforation on the tube wall of interior pipe outlet section, the convergent-divergent pipe that its inlet flushes with this device import is equipped with in interior pipe entrance point upstream, in the pipe phasitron is arranged in the invention is characterized in, this phasitron is connected with the transmission part that is arranged on interior pipe outlet end downstream by drive link, and can move along the tube wall of interior pipe, the flow area of spirality channel and central passage is equal substantially.

Air-flow enters this device behind convergent-divergent pipe current stabilization, just be divided into two-way, one the tunnel through central passage, and its approach is shorter, and another road is through spirality channel, its approach is longer, when meet in the outlet port, if when the length of central passage and spirality channel differs 1/2 wavelength that equals certain frequency sound wave, the pulsed sound of this frequency then, at two passage confluce phase shifts, 180 degree, the anti-phase interference of two homenergic ripples is offset.Phasitron moves in interior pipe, and the high and low position difference of the perforation in hiding on the pipe outlet section has just changed the length difference of central passage and spirality channel, thereby changed interference frequencies, reaches the purpose of adjustable interference frequencies.

The present invention is a FREQUENCY MODULATING EXHAUST SILENCER, and it has following advantage compared with the prior art:

Compact structure, simple can reduce because of interfering significantly to the fluctuation pressure of accent or noise are arranged, and it is effective to eliminate the noise.Its interference frequencies is adjustable continuously arbitrarily, can satisfy the scene requirement that caused interference frequencies changes because of operating conditions changes, and can guarantee to interfere fully.Frequency adjustment range is wide, the machinery of the applicable different main frequencies of device of a specification.

Accompanying drawing is a FREQUENCY MODULATING EXHAUST SILENCER longitudinal section, and the numbering of each component is described as follows among the figure:

The 1-operating handle, 2-aperture, pipe in the 3-phasitron, 4-, 5-outer tube, 6-convergent-divergent pipe, 7-helical baffle, 8-circular hole, 9-upper bracket, 10-screw, 11-lower support frame, 12-screw mandrel, 13-driven bevel pinion, 14-handle, 15-driving bevel gear.

Below in conjunction with accompanying drawing, embodiments of the invention are described in detail.

The structure of FREQUENCY MODULATING EXHAUST SILENCER: interior pipe 4, outer tube 5, convergent-divergent pipe 6, helical baffle 7, be connected with welding or other mechanical fasteners method.A phasitron 3 is arranged in interior pipe 4, and it is connected with nut with usefulness mechanical supports such as handle 14, operating handles 1 with umbrella gear 13,15 by screw mandrel 12.Its inlet of pipe 4 entrance point upstreams flushed with this device import in convergent-divergent pipe 6 was contained in.Air-flow is discharged from gas compressor, and convergent-divergent pipe 6 convergent-divergents by on the FREQUENCY MODULATING EXHAUST SILENCER obtain current stabilization thus.Interior pipe 4 is straight pipe, and its intracavity space is the passage of pulse pneumatic, i.e. central passage.On the tube wall of interior pipe 4 outlet sections, have some apertures 2, for having the noise of accent to begin interference position, frequency modulation uses.In the long section of the perforation of pipe 4 on outlet section tube wall BC(promptly by the B point to the C point, B point is positioned at the upper end first of managing on 4 perforated sections and arranges on the horizontal line of aperture 2.The C point is positioned on the pipe 4 outlet end end face horizontal lines), its length is decided by the requirement of tuning range.The length of phasitron 3 must be greater than the length of BC.The A point is positioned on the pipe 4 entrance point end face horizontal lines, and it is airflow diversion becomes synchronous acoustic pressure wave or pressure wave with spirality channel to central passage a basic point.Helical baffle 7 forms spirality channel between pipe 4 outer walls and outer tube 5 inwalls in being fixed on, the cross-sectional flow area of spirality channel and central passage cross-sectional flow area about equally, with the air-flow that causes two strands of energy to equate substantially.Phasitron 3 is straight pipe, on its two ends end face, respectively adorns a upper bracket 9 and lower support frame 11, and a circular hole 8 is arranged on the upper bracket 9, and a screw 10 is arranged on the lower support frame 11.Screw 10 and screw mandrel 12 engagements.Circular hole 8 is made the usefulness of screw mandrel 12 positioning and guidings.The passive umbrella gear 13 that is contained on screw mandrel 12 ends is meshed with driving bevel gear 15 on being contained in operating handle 1.The tube wall that operating handle 1 passes outer tube 5 links to each other with handle 14.When shaking handle 14, then screw mandrel 12 rotates, and phasitron 3 is moved up and down in interior pipe 4, manages the height of 4 apertures, 2 positions in phasitron 3 hides, and has determined the interference position of sound wave in central passage and the spirality channel.When the difference of two passage lengths that are in this position equals to interfere the odd-multiple of 1/2 wavelength of sound wave and 1/2 wavelength, then its corresponding frequency, the interference frequencies that will regulate exactly.

Exhaust airstream enters this device after convergent-divergent pipe current stabilization, enter two passages that passage section equates substantially at A point shunting two-way, one the tunnel through central passage, its approach is shorter, another road is through spirality channel, its approach is longer, and two strands of air-flows are in the punch position B point junction interference of the unsheltered upper end of interior pipe.The selection of this point can be regulated by operating handle according to the air-flow frequency of sound wave of required interference, the accent pulsation sound wave that has of this frequency just caused the ripple of same frequency, homenergic, antiphase when air-flow arrived the B point two passwaies, it is interfered mutually and offset, determining of B point position, promptly interference frequencies can be provided by following formula:

In f=C/ λ n=2n-1/2 * C/ △ L formula: the f-interference frequencies

C-is by the local velocity of sound of gas

λ n-has the voicing wave-wave long

△ L-central passage and the spirality channel propagation path length difference when the B point

n＝1，2，3，……

Shake handle 14, operating handle 1 rotation through driving bevel gear 15 and driven bevel pinion 13, drives screw mandrel 12 rotations, thereby phasitron 3 is moved up and down along the inner tubal wall of interior pipe 4 outlet sections, to reach the purpose of regulating interference frequencies.

Be configured in a 25800m ³The test result of the FREQUENCY MODULATING EXHAUST SILENCER on the large-scale screw rod gas compressor of/h is listed below: this compressor delivery pressure is 3.8kg/cm ², exhaust has transfers the noise 20～25dB that can decay after interfering, and the frequency adjustable scope is 150～250Hz, device size: latus rectum is φ 400mm, long 1240mm, and size is less, noise reduction is very remarkable, and frequency-tuning range is bigger simultaneously, can satisfy the engineering application need.

The present invention also can be used for the usefulness that low frequency has other mechanical air-flow voltage stabilizing of transferring the fluctuation pressure exhaust, as reciprocating air compressor etc.

Claims (1)

1, a kind of FREQUENCY MODULATING EXHAUST SILENCER, it comprises the interior pipe of coaxial line configuration and the outer tube that there is adpting flange at its two ends, be provided with helical baffle between outer tube and the interior pipe, this dividing plate and outer tube wall and outer wall of inner tube constitute spirality channel, have perforation on the tube wall of interior pipe outlet section, the convergent-divergent pipe that its inlet flushes with this device import is equipped with in interior pipe entrance point upstream, in the pipe phasitron is arranged in the invention is characterized in, this phasitron is connected with the transmission part that is arranged on interior pipe outlet end downstream by drive link, and can move along the tube wall of interior pipe, the flow area of spirality channel and central passage is equal substantially.

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