CN203515733U

CN203515733U - SCR sound deadening cavity

Info

Publication number: CN203515733U
Application number: CN201320476581.7U
Authority: CN
Inventors: 田新伟; 张中业; 桂建华
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2013-08-06
Filing date: 2013-08-06
Publication date: 2014-04-02
Anticipated expiration: 2023-08-06

Abstract

The utility model relates to an SCR sound deadening cavity which comprises a box body. The front end of the box body is connected with an air inlet pipe, the rear end of the box body is connected with an exhaust pipe, and three partition plates in the box body divide an inner cavity of the box body into an expansion cavity, an interference cavity, an extension cavity and a tail cavity in sequence. A perforated pipe communicated with the air inlet pipe is arranged in the box body and enters the interference cavity after penetrating through the expansion cavity and the front partition plate, and a catalytic carrier transversely penetrating through the interference cavity is communicated between the expansion cavity and the extension cavity; waste gas and urea water solution can be fully mixed, the SCR sound deadening cavity has a good noise reduction effect on medium and low frequency sound waves, low-frequency noise of the third order of rotating frequency in exhaust sound waves is reduced, the energy of the sound waves is consumed, acoustic impedance is changed, transfer loss of the overall broadband of the sound waves is increased, and good exhaust and noise reduction effects are achieved.

Description

A kind of SCR silencing cavity

Technical field

The utility model relates to a kind of SCR silencing cavity.

Background technique

Diesel engine is the internal-combustion engine that thermal energy conversion efficiency is higher, along with the reinforcement gradually of country's discharge and legislations for noise, improves emission level and reduce exhaust noise more and more outstanding.SCR technology belongs to external purification, utilize urea liquid to process main exhaust gas constituents oxynitrides in diesel exhaust gas, diesel engine is loop cycle burning, acting and intake and exhaust, cause exhaust pulses between each cylinder, in tailpipe, form strong pulsing airflow, cause radiated noise, therefore, in SCR reprocessing, increase noise reduction original paper, the noise that reduces Purge gas has been a kind of development trend, and baffler effect is eliminated exhaust noise by improving the pressure loss with decay gas exactly.

Engine working process need to constantly enter air, discharge large quantity of exhaust gas, depend merely on the requirement that SCR case is difficult to meet discharge and noise reduction simultaneously, the silencing apparatus of at present large capacity diesel engine has expansion cavity, resonant cavity, the structures such as perforated plate, what have also fills heat-resisting sound absorbing material in silencing apparatus, the general composite structure that adopts reaches noise elimination object, the baffler majority of large-scale diesel engine is selected resistance or combination baffler, according to the frequency band of exhaust sound, selectively carry out noise reduction processing, resistant noise-reducing device utilizes acoustic reflection to reduce band segment noise, centering high frequency noise erasure effect is poor, combined muffler is resistive and the combination of resistant noise-reducing device, improve its whole acoustical behavior, but often increase vent systems back pressure, cause power loss to increase, so in order to reduce diesel engine power loss ratio and exhaust back pressure, often sacrifice exhaust acoustical behavior, cause noise reduction level not up to standard, the discontented tread of SCR baffler acoustical behavior is learned requirement.

Model utility content

The technical problems to be solved in the utility model is to provide a kind of simple in structure, SCR silencing cavity that decrease of noise functions is strong.

For solving the problems of the technologies described above, the utility model comprises that front end is connected with the casing that suction tude, rear end are connected with outlet pipe, in casing, be provided with catalytic carrier, its structural feature is in described casing, to be provided with front dividing plate, central diaphragm and rear bulkhead, described rear bulkhead comprises the perforated plate of bottom and the solid separator on top, between the joint of perforated plate and solid separator and central diaphragm, be provided with dividing plate, described front dividing plate, central diaphragm, rear bulkhead and dividing plate are separated into expansion chamber, interference cavity, expansion cavity, resonant cavity and last chamber successively by cabinets cavity; Described dividing plate, solid separator and central diaphragm get up expansion cavity top seal and form resonant cavity, and described dividing plate is provided with the resonance lumen that is communicated with resonant cavity and expansion cavity, and described perforated plate is provided with the trunnion that is communicated with expansion cavity and last chamber; On described front dividing plate, offer a plurality of through holes, in casing, be provided with the perforated pipe being communicated with suction tude.

Described perforated pipe is passed in interference cavity after passing expansion chamber and front dividing plate, and the part that perforated pipe is positioned at interference cavity offers a plurality of perforation that are communicated with interference cavity, and the bottom of perforated pipe is sealed by central diaphragm; Between expansion chamber and expansion cavity, be communicated with the catalytic carrier that crosses front dividing plate and central diaphragm and be arranged in interference cavity.

Described perforated plate and expansion cavity are contour.

The centre of described perforated plate is provided with noise reduction layer.

The depressed part of quieter material is outwards heaved and in casing, be formed for filling to the rear end cover of described casing, is provided with and on orifice plate and orifice plate, is densely covered with a plurality of through holes that are communicated with depressed part between depressed part and last chamber.

Adopt the SCR silencing cavity of said structure compared with prior art to have the following advantages: SCR baffler adopts resistance, resistive combined type noise-reducing structure, mixed gas enters casing through suction tude, through perforated pipe, enter interference cavity, waste gas is mixed with aqueous solution of urea fully, avoid aqueous solution of urea to mix inequality with tail gas and cause crystallization, mixed gas further mixes after entering expansion chamber, silencer element adopts expansion cavity, resonant cavity, the combination such as trunnion and perforated plate, centering, low-frequency sound wave plays good Noise Reduction, effectively reduce the transfer of exhaust sound wave low-frequency noise and the consumption acoustic wave energy on three rank frequently, utilize variable section structure to change acoustic impedance, make forward sound wave and on different pipeline sections, between reflected wave, produce the phase difference of 180 °, mutually interfere sound energy consumption, improve acoustic efficiency, in perforated plate, be filled with silencing cotton, the radio-frequency component that trunnion is produced has good consumption effect, silencing cotton and medium, high frequency sound wave reflect mutually, friction generates heat consumes, improved the acoustical behavior of silencer element wideband, the secondary noise radiation of having avoided trunnion to produce, can reach good noise reduction.Visible, the utility model has increased the transmission loss of the whole wideband of sound wave, has played good exhausting and denoising effect.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail:

Fig. 1 is structural representation of the present utility model.

Embodiment

With reference to accompanying drawing, this SCR silencing cavity comprises that front end is connected with the casing 16 that suction tude 1, rear end are connected with outlet pipe 10, in casing 16, be provided with catalytic carrier 14, in casing 16, be provided with front dividing plate 18, central diaphragm 19 and rear bulkhead, described rear bulkhead comprises the perforated plate 11 of bottom and the solid separator 9 on top, between the joint of perforated plate 11 and solid separator 9 and central diaphragm 19, be provided with diaphragm 17, described front dividing plate 18, central diaphragm 19, rear bulkhead and diaphragm 17 are separated into expansion chamber 15, interference cavity 3, expansion cavity 13, resonant cavity 4 and last chamber 6 successively by cabinets cavity; Diaphragm 17, solid separator 9 and central diaphragm 19 get up expansion cavity 13 top seals and form resonant cavity 4, and diaphragm 17 is provided with the resonance lumen 5 that is communicated with resonant cavity 4 and expansion cavity 13, and perforated plate 11 is provided with the trunnion 7 that is communicated with expansion cavity 13 and last chamber 6; On front dividing plate 18, offer a plurality of through holes, in casing 16, be provided with the perforated pipe 2 being communicated with suction tude 1, after passing expansion chamber 15 and front dividing plate 18, perforated pipe 2 is passed in interference cavity 3, the part that perforated pipe 2 is positioned at interference cavity 3 offers a plurality of perforation that are communicated with interference cavity 3, and the bottom of perforated pipe 2 is sealed by central diaphragm 19; Between expansion chamber 15 and expansion cavity 13, be communicated with the catalytic carrier 14 that crosses front dividing plate 18 and central diaphragm 19 and be arranged in interference cavity 3, catalytic carrier 14 be arranged in parallel with perforated pipe 2, in catalytic carrier 14, catalyzer is housed, mixed gas carries out reduction reaction under the effect of catalyzer, generate nitrogen and water vapour, in the present embodiment, catalytic carrier 14 is cuboids, and tube wall damping function edge sound wave plays rubbing action, makes part acoustic energy be converted into thermal energy consumption and falls.Perforated plate 11 is contour with expansion cavity 13, and the top of perforated plate 11 is resonant cavity 4, and the bottom of perforated plate 11 is expansion cavity 13.The present embodiment middle punch plate 11 is composite sheet perforated plate, and the centre of perforated plate 11 is provided with noise reduction layer 12.The depressed part of quieter material is outwards heaved and be formed for filling in casing 16 to the rear end cover of casing 16, between depressed part and last chamber 6, be provided with on orifice plate 8 and orifice plate 8 and be densely covered with a plurality of through holes that are communicated with depressed part, the quieter material in the present embodiment in depressed part is silencing cotton.

Mixed gas enters casing through suction tude 1 as shown in Figure 1, and enter interference cavity 3 through perforated pipe 2, waste gas is mixed with aqueous solution of urea fully, avoid aqueous solution of urea to mix inequality with tail gas and cause crystallization, mixed air-flow enters expansion chamber 15 through the through hole on front dividing plate 18 further to be mixed, mixed airflow enters catalytic carrier 14 by expansion chamber 15 again, mixed gas carries out reduction reaction under the effect of catalyzer, generate nitrogen and water vapour, simultaneously catalytic carrier 14 makes part acoustic energy be converted into thermal energy consumption to fall, then gas enters expansion cavity 13 through catalytic carrier 14, air-flow changes in the interior generation acoustic impedance of expansion cavity 13, acoustic wave segment is reflected back sound source by the wooden partition of perforated plate 11, form the reflected wave with incident acoustic wave single spin-echo, mutually interfere stack, eliminate acoustic wave segment energy, acoustic wave segment enters resonant cavity 4 by resonance lumen 5, 4 pairs of low frequency noises of resonant cavity resonate, sound energy consumption, air-flow after resonance is back in expansion cavity 13 by resonance lumen 5 again, wherein most of air-flow enters last chamber 6 through trunnion 7, part air-flow enters last chamber 6 through perforated plate 11, air-flow high frequency sound wave is through the noise reduction layer 12 in perforated plate 11, friction generates heat in noise reduction layer 12 for sound wave, consume acoustic wave energy, air-flow enters last chamber 6 and enters silencing cotton through the through hole on orifice plate 16, silencing cotton frictional damping centering, high-frequency sound energy changes heat energy into and consumes, the secondary high-frequency noise of having avoided trunnion to produce, improved the transmission loss of the overall frequency section of baffler, reduce exhaust sound object, air-flow after flat is discharged flat case by steam outlet pipe.

In sum, the utility model is not limited to above-mentioned embodiment.Those skilled in the art, not departing under the prerequisite of spirit and scope of the present utility model, can do some changes and modification.Protection domain of the present utility model should be as the criterion with claim of the present utility model.

Claims

1. a SCR silencing cavity, comprise that front end is connected with suction tude (1), rear end is connected with the casing (16) of outlet pipe (10), in casing (16), be provided with catalytic carrier (14), it is characterized in that being provided with in described casing (16) front dividing plate (18), central diaphragm (19) and rear bulkhead, described rear bulkhead comprises the perforated plate (11) of bottom and the solid separator (9) on top, between the joint of perforated plate (11) and solid separator (9) and central diaphragm (19), be provided with diaphragm (17), described front dividing plate (18), central diaphragm (19), rear bulkhead and diaphragm (17) are separated into expansion chamber (15) successively by cabinets cavity, interference cavity (3), expansion cavity (13), resonant cavity (4) and last chamber (6), described diaphragm (17), solid separator (9) and central diaphragm (19) get up expansion cavity (13) top seal form resonant cavity (4), described diaphragm (17) is provided with the resonance lumen (5) that is communicated with resonant cavity (4) and expansion cavity (13), and described perforated plate (11) is provided with the trunnion (7) that is communicated with expansion cavity (13) and last chamber (6), on described front dividing plate (18), offer a plurality of through holes, in casing (16), be provided with the perforated pipe (2) being communicated with suction tude (1).

2. SCR silencing cavity according to claim 1, it is characterized in that being passed in interference cavity (3) after described perforated pipe (2) is through expansion chamber (15) and front dividing plate (18), the part that perforated pipe (2) is positioned at interference cavity (3) offers a plurality of perforation that are communicated with interference cavity (3), and the bottom of perforated pipe (2) is sealed by central diaphragm (19); Between expansion chamber (15) and expansion cavity (13), be communicated with the catalytic carrier (14) that crosses front dividing plate (18) and central diaphragm (19) and be arranged in interference cavity (3).

3. SCR silencing cavity according to claim 2, is characterized in that described perforated plate (11) and expansion cavity (13) are contour.

4. SCR silencing cavity according to claim 3, is characterized in that the centre of described perforated plate (11) is provided with noise reduction layer (12).

5. SCR silencing cavity according to claim 1, it is characterized in that the rear end cover of described casing (16) outwards heaves and be formed for filling in casing (16) depressed part of quieter material, between depressed part and last chamber (6), be provided with on orifice plate (8) and orifice plate (8) and be densely covered with a plurality of through holes that are communicated with depressed part.