CN204388169U - A kind of denoising device of range hood - Google Patents
A kind of denoising device of range hood Download PDFInfo
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- CN204388169U CN204388169U CN201420818728.0U CN201420818728U CN204388169U CN 204388169 U CN204388169 U CN 204388169U CN 201420818728 U CN201420818728 U CN 201420818728U CN 204388169 U CN204388169 U CN 204388169U
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- silencing
- noise reduction
- range hood
- microphone
- pipeline
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Abstract
A kind of denoising device of range hood, it is characterized in that: at air inlet, lower silencing means is removably installed, lower silencing means comprises at least one noise reduction unit, noise reduction unit comprises the silencing pipeline longitudinally arranged, the upper end of silencing pipeline communicates with air inlet, lower end communicates with exhaust fume collecting hood air outlet, at the air intake of silencing pipeline, loudspeaker is installed, the inwall of silencing pipeline be provided with reference to microphone and and be positioned at reference to the error microphone below microphone, be controlled by active noise reduction controller with reference to microphone, error microphone and loudspeaker.The utility model is by silencing means under air inlet is detachably installed, do not need that transformation is carried out to the internal structure of range hood and just can realize noise reduction, silencing means can freely be dismantled and assemble, there is good versatility and adaptability, solve range hood inlet noise problem well, then can solve range hood gas outlet noise problem by detachably installing silencing means at fan outlet.
Description
Technical field
The utility model relates to a kind of range hood, especially relates to a kind of denoising device of range hood.
Background technology
Range hood comprises blower fan, air inlet filter screen and range hood pipeline, and blower fan is driven by motor with the oil smoke of sucking-off range hood pipeline inside.Blower fan, motor are important noise sources, and wherein aerodynamic noise also comprises that air stream turbulence noise in range hood pipeline is gentle flows through air inlet filter screen and the noise produced.
At present, the noise reducing range hood mainly still adopts the mode of passive noise reduction, passive noise reduction generally by adopting aerodynamic method to be optimized centrifugal blower, spiral case, or adopts the motor of low noise, or uses sound insulation or sound-absorbing material.Although above-mentioned various passive noise reduction mode also can reduce noise, it is while reduction noise, often cause cost increase or with the smoke evacuation air quantity reducing range hood for cost, and noise reduction is not fairly obvious.As improvement, also the noise being reduced range hood by the mode of active noise reduction is had in prior art, in the active noise reduction mode of range hood, the impact of air-flow on microphone is and key, and the disturbance of air-flow greatly disturbs stability and the noise reduction of active noise reduction control system.About range hood active noise reduction can application reference number for " active noise reducing device and method and the noise control system for smoke exhaust ventilator " disclosed in the Chinese invention patent application of 201110102161.2 (application publication number is CN 103035234 A) and the patent No. be " range hood of band active noise reducing device " disclosed in ZL 201120253295.5 (Authorization Notice No. is CN 202188543 U) Chinese invention patent, the major defect that above-mentioned active noise reduction system exists has: because denoising device is placed on lampblack absorber inside, need to transform lampblack absorber inside, not only design trouble, and certain interference can be produced to blower fan system, and noise reduction is not had to the vibration noise of lampblack absorber outer wall.In addition, do not relate to for the anti-storm design of microphone in lampblack absorber and pipe design, the stability of its noise reduction system and validity are not good.
Utility model content
Technical problem to be solved in the utility model is for above-mentioned prior art present situation, provides a kind of needs to carry out transforming the range hood denoising device that just can realize noise reduction to the internal structure of range hood.
The utility model solves the problems of the technologies described above adopted technical scheme: the denoising device of this range hood, it is characterized in that: at air inlet, lower silencing means is removably installed, described lower silencing means comprises at least one noise reduction unit, described noise reduction unit comprises the silencing pipeline longitudinally arranged, the upper end of described silencing pipeline is outlet air end and communicates with air inlet, the lower end of described silencing pipeline is air intake and communicates with exhaust fume collecting hood air outlet, at the air intake of described silencing pipeline, voice directions and air-flow are installed and flow into the contrary loudspeaker in the direction of silencing pipeline, be provided with reference to microphone and error microphone at the inwall of described silencing pipeline, described error microphone is located at the below with reference to microphone, and described reference microphone, error microphone and loudspeaker are controlled by the active noise reduction controller be arranged on silencing pipeline.
In order to reduce the noise of fan outlet, the denoising device of this range hood is removably provided with silencing means at fan outlet, described upper silencing means comprises at least one noise reduction unit be inverted by the noise reduction unit in lower silencing means, the silencing pipeline upper end of the noise reduction unit of this inversion is outlet air end and communicates with the flue of range hood, and the silencing pipeline lower end of the noise reduction unit of this inversion is air intake and communicates with fan outlet.Similarly, the silencing pipeline of upper silencing means is also provided with reference to microphone, error microphone, loudspeaker and active noise reduction controller, and is controlled by active noise reduction controller with reference to microphone, error microphone, loudspeaker.
In order to make the test surface with reference to microphone and error microphone wider and make to calibrate for error more accurate, the cross section of the silencing pipeline of described upper silencing means and lower silencing means is hexagon, at the inwall of each silencing pipeline, the error microphone described in reference microphone described in three and three is all installed, described reference microphone is distributed in wherein three edges of silencing pipeline inwall, described error microphone is distributed in other three edges of silencing pipeline inwall, and, stagger up and down a corner error microphone with form matched group with reference to microphone.Change the cross section of pipeline into six distortion by four traditional distortion, can expand the cut-off frequency of pipeline, improve effective noise reduction frequency band, as long as noise source frequency is lower than pipeline cut-off frequency, the stability of system and validity can increase substantially.In addition, by installing the right reference microphone of three assembly and error microphone, sensitivity and the noise reduction stability of active noise reduction system can be improved.
In order to obtain good noise reduction, the air line distance d between the reference microphone of described matched group and error microphone and between noise source wave length of sound λ meet:
In order to make the noise reduction of denoising device best, the air line distance d between the reference microphone of described matched group and error microphone and meet d=0.3 λ between noise source wave length of sound λ.
In order to the vibration noise reducing conduit enclosure outwards transmits, at the inwall of described silencing pipeline, sound absorbing layer is installed.Sound absorbing layer preferably adopts melamine foamed plastic layer; melamine foamed plastic is good windproof protective layer; by arranging the sound absorbing layer be made up of melamine foamed plastic; the drawback that range hood internal gas flow velocity is large, air-flow is unstable can be overcome; ensure the stability of active noise reduction system and good noise reduction, and effectively minimizing vibration noise outwardly transmits.
Further preferably, stationary magazine creel is provided with in the inside of described silencing pipeline, described sound absorbing layer is folded between described silencing pipeline inwall and stationary magazine creel outer wall, acoustic resonance chamber is provided with at the rear portion of described loudspeaker, in the silencing pipeline stated, be provided with the sound-absorbing part coaxial with loudspeaker, described sound-absorbing part is fixed on described stationary magazine creel by bracing frame away from one end of loudspeaker.Arranging acoustic resonance chamber at loudspeaker rear portion can so that the sound phase silencing pipeline outside of loudspeaker be transmitted, sound-absorbing part adopts melamine foamed plastic, play brokenly the effect of whirlpool and sound-absorbing, namely an one effect reduces the toll bar whirlpool of air-flow by producing after loudspeaker, thus reduction pneumatic noise, another effect increases passive sound-absorbing effect, absorb the high-frequency noises at air inlet and gas outlet place, increase for ducted stable standing wave assimilation effect, and then increase the cut-off frequency of pipeline, thus increase effective noise reduction frequency band of active noise reducing device.
In order to more effectively eliminate toll bar whirlpool, described sound-absorbing part is truncated cone-shaped or taper shape, and the stub end of sound-absorbing part is near described loudspeaker.Certainly, sound-absorbing part also can adopt other shapes such as square or cylindrical.
Can freely dismantle to make upper silencing means and lower silencing means and assemble, described lower silencing means and upper silencing means include and are arranged on upper mounting plate on silencing pipeline and lower installation board, lower installation board in described lower silencing means is detachably arranged on the exhaust fume collecting hood of range hood, upper mounting plate in lower silencing means is detachably arranged on the hood of range hood, lower installation board in described upper silencing means is detachably arranged on the hood of range hood, and the upper mounting plate in described upper silencing means is detachably arranged on the flue of range hood.
In order to improve the noise reduction of device further, described upper silencing means and lower silencing means have included two noise reduction unit, and two noise reduction unit in lower silencing means lay respectively at the left and right sides of air inlet, two noise reduction unit in upper silencing means lay respectively at the left and right sides of fan outlet.Consider exhaust fume collecting hood and blower sizes, upper silencing means and lower silencing means all adopt two noise reduction unit the most suitable.
Compared with prior art, the utility model has the advantage of: the denoising device of this range hood is removably provided with lower silencing means at air inlet, lower silencing means by being provided with reference to microphone on its silencing pipeline, error microphone, loudspeaker and active noise reduction controller realize active noise reduction, do not need that transformation is carried out to the internal structure of range hood and just can realize noise reduction, silencing means can freely be dismantled and assemble, there is good versatility and adaptability, solve range hood inlet noise problem well, by removably installing at fan outlet the noise problem that silencing means can solve range hood gas outlet, in addition, by upper, the silencing pipeline inwall of lower silencing means is installed sound absorbing layer and is realized passive noise reduction, effective minimizing vibration noise outwardly transmits, make the noise reduction of whole device better.
Accompanying drawing explanation
Fig. 1 is the mounting structure schematic diagram of the utility model embodiment one;
Fig. 2 is the decomposing schematic representation of mounting structure shown in Fig. 1;
Fig. 3 is the structural representation of the upper silencing means of the utility model embodiment one;
Fig. 4 is the structural representation of the lower silencing means of the utility model embodiment one;
Fig. 5 is the top view of a noise reduction unit in lower silencing means shown in Fig. 4;
Fig. 6 is the upward view of a noise reduction unit in lower silencing means shown in Fig. 4;
Fig. 7 is for removing the structural representation after silencing pipeline in silencing means lower described in Fig. 4;
Fig. 8 is the mounting structure schematic diagram of the utility model embodiment two.
Detailed description of the invention
Below in conjunction with accompanying drawing embodiment, the utility model is described in further detail.
Embodiment one:
As shown in Figures 1 to 7, the denoising device of the range hood in the present embodiment includes upper and lower two groups of silencing means, lower silencing means 1 is removably mounted on air inlet 6, upper silencing means 2 is removably mounted on fan outlet 7, user can carry out freely dismantling and assembling as required, have good versatility, the noise for any blower fan system has good self application.In the present embodiment, upper silencing means 2 and lower silencing means 1 have included upper mounting plate 3, lower installation board 4 and two noise reduction unit 5, two noise reduction unit 5 in lower silencing means 1 lay respectively at the left and right sides of air inlet 6, and two noise reduction unit 5 in upper silencing means 2 lay respectively at the left and right sides of fan outlet 7.Lower installation board 4 in lower silencing means 1 is detachably arranged on the exhaust fume collecting hood 8 of range hood, upper mounting plate 3 in lower silencing means 1 is detachably arranged on the hood 9 of range hood, lower installation board 4 in upper silencing means 2 is detachably arranged on the hood 9 of range hood, and the upper mounting plate 3 in upper silencing means 2 is detachably arranged on the flue (not shown) of range hood.
A noise reduction unit 5 in following silencing means 1 is described for example, this noise reduction unit 5 comprises the silencing pipeline 50 longitudinally arranged, the upper end of silencing pipeline 50 is outlet air end and communicates with air inlet 6, and the lower end of silencing pipeline 50 is air intake and communicates with exhaust fume collecting hood air outlet 81.At the air intake of silencing pipeline 50, voice directions is installed contrary with the direction that air-flow flows into silencing pipeline 50.Be provided with reference to microphone 52 and error microphone 53 at the inwall of silencing pipeline 50, error microphone 53 is located at below with reference to microphone 52 and closer to loudspeaker 51, and is controlled by the active noise reduction controller 54 be arranged on silencing pipeline 50 with reference to microphone 52, error microphone 53 and loudspeaker 51.
In order to make the test surface with reference to microphone 52 and error microphone 53 wider and make to calibrate for error more accurate, silencing pipeline cross section is hexagon, three are provided with reference to microphone 52 and three error microphone 53 at the inwall of silencing pipeline 50, wherein three edges of silencing pipeline 50 inwall are distributed in reference to microphone 52, error microphone 53 is distributed in other three edges of silencing pipeline 50 inwall, further, the error microphone 53 of a corner of staggering up and down forms matched group with reference to microphone 52.Change the cross section of pipeline into six distortion by four traditional distortion, can expand the cut-off frequency of pipeline, improve effective noise reduction frequency band, as long as noise source frequency is lower than pipeline cut-off frequency, the stability of system and validity can increase substantially.Further, by installing the right reference microphone of three assembly and error microphone, sensitivity and the noise reduction stability of active noise reduction system can be improved.
In order to obtain better noise reduction, meet between the air line distance d between the reference microphone 52 of pairing in this noise reduction unit 5 and error microphone 53 and noise source wave length of sound λ:
in general, the reference loudspeaker of pairing and the distance of error loudspeaker less, control effects is better, and as the sound wave for 1000Hz, primary and secondary sound source distance is no more than 340/2000=0.017m.When often match meet d=0.3 λ between the air line distance d of reference microphone and error microphone and noise source wave length of sound λ time, system noise reduction is best.In addition, the single distance with reference to loudspeaker and three error loudspeakers be respectively 0.1 times of wavelength, 0.2 times of wavelength and 0.3 times wavelength time, system also can obtain better noise reduction.Meanwhile, all more than the wavelength of 0.1 times, just good noise reduction may can not be realized with reference to the distance between microphone 52 and air inlet 6 in noise reduction unit 5.
Range hood denoising device in the present embodiment also includes passive denoising structure, and this passive denoising structure is installs sound absorbing layer 55 at the inwall of silencing pipeline 50.Sound absorbing layer 55 preferably adopts melamine foamed plastic layer; melamine foamed plastic is good windproof protective layer; one deck melamine foamed plastic is close to reference to outside microphone 52 and error microphone 53; in order to match with hexahedral pipeline; melamine foamed plastic is also hexahedron, can be arranged on easily on inner-walls of duct 50.By arranging the sound absorbing layer 55 be made up of melamine foamed plastic, the drawback that range hood internal gas flow velocity is large, air-flow is unstable can be overcome, ensure that the stability of active noise reduction system and good noise reduction, and effectively minimizing vibration noise outwardly transmits.After sound absorbing layer 55 is installed, be equivalent to be embedded in the middle of sound absorbing layer 55 with reference to microphone 52 and error microphone 53.
In addition, be provided with stationary magazine creel 56 in the inside of silencing pipeline 50, sound absorbing layer 55 is folded between silencing pipeline 50 inwall and stationary magazine creel 56 outer wall.Be provided with acoustic resonance chamber 57 at the rear portion of loudspeaker 51, acoustic resonance chamber 57 can so that the sound of loudspeaker transmits to silencing pipeline 50 outside.The sound-absorbing part 58 coaxial with loudspeaker 51 is provided with in silencing pipeline 50.In the present embodiment, sound-absorbing part 58 adopts melamine foamed plastic and is truncated cone-shaped or taper shape, and sound-absorbing part 58 is stub end near one end of loudspeaker 51, and sound-absorbing part 58 is that little head end is fixed on stationary magazine creel 56 by bracing frame 59 away from one end of loudspeaker 51.This sound-absorbing part 58 can play brokenly the effect of whirlpool and sound-absorbing, particularly, an effect reduces the toll bar whirlpool of air-flow by producing after loudspeaker, thus reduction pneumatic noise, another effect increases passive sound-absorbing effect, absorbs the high-frequency noises at fan air inlet place, increase for the stable standing wave assimilation effect in silencing pipeline, and then increase the cut-off frequency of silencing pipeline, thus increase effective noise reduction frequency band of active noise reducing device.
In the present embodiment, two noise reduction unit 5 of upper silencing means 2 are inverted by two noise reduction unit of lower silencing means and are formed, the voice directions of the loudspeaker 51 of the noise reduction unit 5 after this inversion is consistent with the direction that air-flow flows out silencing pipeline 50, and on this, the concrete structure of silencing means no longer launches to describe at this.During installation, the silencing pipeline upper end of the noise reduction unit of this inversion is outlet air end and communicates with the flue of range hood, and the silencing pipeline lower end of the noise reduction unit of this inversion is air intake and communicates with fan outlet.
In the present embodiment, controlling with reference to microphone, error microphone and loudspeaker with active noise reduction controller is conventional prior art, following silencing means is example, and its specific algorithm controlled is as follows: the noise that blower fan sends is primary noise, by lower silencing means from lampblack absorber smoke collecting chamber out.Sub loudspeaker in lower silencing means lower end is for offsetting primary noise, and its amplitude is equal with primary noise, and phase place is contrary.The sound driver signal of sub loudspeaker is realized by many microphones transfer function method by the dsp chip of system control unit, and reference microphone here and error microphone have employed the mode of microphone array, adopts multiple microphone to carry out the mode of matching respectively.Be arranged in silencing pipeline top near blower fan position with reference to microphone array, error microphone permutation is arranged near sub loudspeaker position.In order to more accurately measure the sound field below blower fan, the distance between each microphone and blower fan should be variant.On algorithm, the data recorded with reference to each microphone in microphone array carry out matching by processor, the most real sound field environment of simulation, and the same data to error microphone arranges that also need carry out process of fitting treatment.Adopt reaction type signal iterative manner that whole system is restrained and keep stable.Specific practice is: obtain the first input end of fan noise signal as active noise reduction controller with reference to microphone array, and active noise reduction controller exports and drives speaker operation.In order to reach the object of noise reduction, near loudspeaker, step-up error sensor array obtains this place's voice signal and feeds back to the second input of active noise reduction controller, active noise reduction controller carrys out the weight coefficient of self adaptation regulation output signal according to the otherness of two sensor array data, loudspeaker output intensity can change, by the mode of successive ignition, finally reach noise reduction object.
Active noise reduction controller inside is provided with master control borad, and master control borad is made up of DSP, power management module, exented memory module, power amplifier, multiple wave filter and ad/da converter.Wherein power management module provides stable voltage for DSP and each wave filter; Exented memory provides data storage for during large-scale data process; Microphone by after the module such as frequency overlapped-resistable filter, analog-digital converter by signal to DSP; Loudspeaker end, signal is sent by DSP, by digital to analog converter, reconfigurable filter, power amplifier etc., loudspeaker is sounded; Each collecting sensor signal adopts polling mechanism, and DSP carrys out samsara gather each sensor signal by sending chip selection signal.
Embodiment two:
As shown in Figure 8, denoising device in the present embodiment is only provided with lower silencing means 1 at air inlet 6, and this lower silencing means 1 also includes two noise reduction unit 5, the structure of this noise reduction unit 5 is identical with the noise reduction cellular construction in embodiment one, does not launch to describe at this.
The foregoing is only preferred embodiment of the present utility model, should be understood that, for those of ordinary skills, do not departing under principle prerequisite of the present utility model, multiple remodeling or improvement can be carried out to the utility model, respectively can arrange a noise reduction unit than following silencing means and upper silencing means, such as can reserve again expansion mouth on corresponding upper mounting plate and lower installation board, expansion confession needs to enable when installation two noise reduction unit.These are all regarded as within protection domain of the present utility model.
Claims (10)
1. the denoising device of a range hood, it is characterized in that: at air inlet (6), lower silencing means (1) is removably installed, described lower silencing means (1) comprises at least one noise reduction unit (5), described noise reduction unit (5) comprises the silencing pipeline (50) longitudinally arranged, the upper end of described silencing pipeline (50) is outlet air end and communicates with air inlet (6), the lower end of described silencing pipeline (50) is air intake and communicates with exhaust fume collecting hood air outlet (81), at the air intake of described silencing pipeline (50), voice directions and air-flow are installed and flow into the contrary loudspeaker (51) in the direction of silencing pipeline (50), be provided with reference to microphone (52) and error microphone (53) at the inwall of described silencing pipeline (50), described error microphone (53) is located at the below with reference to microphone (52), and described reference microphone (52), error microphone (53) and loudspeaker (51) are controlled by the active noise reduction controller (54) be arranged on silencing pipeline (50).
2. the denoising device of range hood according to claim 1, it is characterized in that: at fan outlet (7), upper silencing means (2) is removably installed, described upper silencing means (2) comprises at least one noise reduction unit (5) be inverted by the noise reduction unit in lower silencing means, silencing pipeline (50) upper end of the noise reduction unit (5) of this inversion is outlet air end and communicates with the flue of range hood, and the silencing pipeline lower end of the noise reduction unit (5) of this inversion is air intake and communicates with fan outlet (7).
3. the denoising device of range hood according to claim 2, it is characterized in that: the cross section of the silencing pipeline (50) of described upper silencing means (2) and lower silencing means (1) is hexagon, at the inwall of each silencing pipeline (50), the error microphone (53) described in reference microphone (52) described in three and three is all installed, described reference microphone (52) is distributed in wherein three edges of silencing pipeline (50) inwall, described error microphone (53) is distributed in other three edges of silencing pipeline (50) inwall, and, stagger up and down a corner error microphone (53) with reference to microphone (52) form matched group.
4. the denoising device of range hood according to claim 3, is characterized in that: meet between the air line distance d between the reference microphone (52) of described matched group and error microphone (53) and noise source wave length of sound λ:
5. the denoising device of range hood according to claim 4, is characterized in that: meet d=0.3 λ between the air line distance d between the reference microphone (52) of described matched group and error microphone (53) and noise source wave length of sound λ.
6. the denoising device of range hood according to claim 2, is characterized in that: be provided with sound absorbing layer (55) at the inwall of described silencing pipeline (50).
7. the denoising device of range hood according to claim 6, it is characterized in that: be provided with stationary magazine creel (56) in the inside of described silencing pipeline (50), described sound absorbing layer (55) is folded between described silencing pipeline (50) inwall and stationary magazine creel (56) outer wall, acoustic resonance chamber (57) is provided with at the rear portion of described loudspeaker (51), the sound-absorbing part (58) coaxial with loudspeaker is provided with in described silencing pipeline (50), described sound-absorbing part (58) is fixed on described stationary magazine creel (56) by bracing frame (59) away from one end of loudspeaker.
8. the denoising device of range hood according to claim 7, is characterized in that: described sound-absorbing part (58) is truncated cone-shaped or taper shape, and the stub end of sound-absorbing part (58) is near described loudspeaker (51).
9. the denoising device of range hood according to claim 2, it is characterized in that: described lower silencing means (1) and upper silencing means (2) include and be arranged on upper mounting plate (3) on silencing pipeline (50) and lower installation board (4), lower installation board (4) in described lower silencing means (1) is detachably arranged on the exhaust fume collecting hood (8) of range hood, upper mounting plate (3) in lower silencing means (1) is detachably arranged on the hood (9) of range hood, lower installation board (4) in described upper silencing means (2) is detachably arranged on the hood (9) of range hood, upper mounting plate (3) in described upper silencing means (2) is detachably arranged on the flue of range hood.
10. the denoising device of range hood according to claim 2, it is characterized in that: described upper silencing means (2) and lower silencing means (1) have included two noise reduction unit (5), and two noise reduction unit (5) in lower silencing means (1) lay respectively at the left and right sides of air inlet (6), two noise reduction unit (5) in upper silencing means (2) lay respectively at the left and right sides of fan outlet (7).
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CN201420818728.0U CN204388169U (en) | 2014-12-18 | 2014-12-18 | A kind of denoising device of range hood |
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CN201420818728.0U CN204388169U (en) | 2014-12-18 | 2014-12-18 | A kind of denoising device of range hood |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104534532B (en) * | 2014-12-18 | 2016-09-21 | 宁波方太厨具有限公司 | A kind of denoising device of range hood |
CN106642249A (en) * | 2016-12-02 | 2017-05-10 | 宁波方太厨具有限公司 | Range hood serially connected with double fans |
CN108204620A (en) * | 2016-12-17 | 2018-06-26 | 哈尔滨城林科技股份有限公司 | Commercial mute smoke abatement enclosure |
-
2014
- 2014-12-18 CN CN201420818728.0U patent/CN204388169U/en not_active Withdrawn - After Issue
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104534532B (en) * | 2014-12-18 | 2016-09-21 | 宁波方太厨具有限公司 | A kind of denoising device of range hood |
CN106642249A (en) * | 2016-12-02 | 2017-05-10 | 宁波方太厨具有限公司 | Range hood serially connected with double fans |
CN106642249B (en) * | 2016-12-02 | 2019-09-20 | 宁波方太厨具有限公司 | A kind of concatenated range hood of two fans |
CN108204620A (en) * | 2016-12-17 | 2018-06-26 | 哈尔滨城林科技股份有限公司 | Commercial mute smoke abatement enclosure |
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