CN220566319U - Ventilation noise reduction device and scanning equipment - Google Patents

Abstract

The application provides a ventilation noise reduction device and scanning equipment, this ventilation noise reduction device includes: the annular expansion cavity comprises a ventilating duct, an annular ventilating flow passage, an annular expansion cavity and at least one opening, wherein the opening is arranged on the adjacent side walls of the annular ventilating flow passage and the annular expansion cavity. The annular ventilation flow passage and the annular expansion cavity form an expansion cavity based on the opening, acoustic impedance change is caused, so that a phase difference is generated between sound waves which enter the annular expansion cavity along the annular ventilation flow passage and propagate forwards along the ventilation pipeline, and mutual interference occurs at a ventilation outlet, so that the purpose of noise reduction is achieved. By adopting the ventilation noise reduction device and the scanning equipment, better noise reduction effect can be obtained.

Description

Ventilation noise reduction device and scanning equipment

Technical Field

The application relates to the technical field of noise reduction, in particular to a ventilation noise reduction device and scanning equipment.

Background

A server, a computer, an X-ray source, etc., can emit a large amount of heat during operation, and a cooling fan is usually installed at a corresponding position to dissipate heat. The adoption of the cooling fan for cooling can bring the problem of fan noise, and the fan noise can influence the use experience of a user on corresponding equipment.

The existing noise reduction method mostly realizes noise reduction by reducing noise of a sound source, namely, controlling noise generated by a cooling fan. The optimization of the cooling fan is limited, so that the noise reduction effect brought by the existing noise reduction method is limited.

Disclosure of Invention

Accordingly, an objective of the embodiments of the present application is to provide a ventilation noise reduction device and a scanning device, which are used for solving the technical problem that the noise reduction effect is limited due to the existing noise reduction method.

In a first aspect, embodiments of the present application provide a ventilation noise reduction device, including:

the device comprises a ventilation pipeline, a circumferential ventilation flow channel, a circumferential expansion cavity and at least one opening;

the annular ventilating duct is arranged on the outer side wall of the ventilating duct, and the annular expansion cavity is arranged on the outer side wall of the annular ventilating duct;

the at least one opening is arranged on the adjacent side walls of the annular ventilation flow passage and the annular expansion cavity.

In the implementation process, the ventilation noise reduction device includes: the annular expansion cavity comprises a ventilating duct, an annular ventilating flow passage, an annular expansion cavity and at least one opening, wherein the opening is arranged on the adjacent side walls of the annular ventilating flow passage and the annular expansion cavity. The annular ventilation flow passage and the annular expansion cavity form an expansion cavity based on the opening, acoustic impedance change is caused, so that a phase difference is generated between sound waves which enter the annular expansion cavity along the annular ventilation flow passage and propagate forwards along the ventilation pipeline, and mutual interference occurs at a ventilation outlet, so that the purpose of noise reduction is achieved. By adopting the ventilation noise reduction device and the scanning equipment, better noise reduction effect can be obtained. The technical problem that the noise reduction effect is limited due to the existing noise reduction method is solved.

Optionally, in an embodiment of the present application, the apparatus further includes: a plurality of first and second dividing baffles; the first separation baffle is configured to separate the annular ventilation flow passage into a plurality of annular flow passages; the second separation baffle is further configured to separate the circumferential expansion cavity into a plurality of expansion chambers; wherein, every two annular flow passages are not communicated with each other, and every two expansion chambers are not communicated with each other; the at least one opening is arranged on the adjacent side wall of each annular flow passage and the corresponding expansion chamber.

In the implementation process, the annular ventilation flow channels and the annular expansion cavities are divided based on the first separation baffle plates and the second separation baffle plates respectively, and openings are formed in adjacent side walls of each annular flow channel and the corresponding expansion cavity to form a plurality of expansion cavities. And further realize the noise reduction of a plurality of noise frequencies based on a plurality of expansion cavities.

Optionally, in an embodiment of the present application, each of the circumferential flow channels is located on the same plane as the first and second separation baffles on the same side of the corresponding expansion chamber.

In the implementation process, as the first separation baffle and the second separation baffle on the same side of the annular flow channel and the corresponding expansion chamber are positioned on the same plane, the first separation baffle and the corresponding second separation baffle can be implemented by the same baffle, the structure of the ventilation noise reduction device is simplified, and meanwhile, the production and manufacturing process of the ventilation noise reduction device is simplified, and further, the production and manufacturing cost of the ventilation noise reduction device is reduced.

Optionally, in an embodiment of the present application, a plurality of the first separation baffles are uniformly distributed around an outer sidewall of the ventilation duct; and a plurality of the second partition baffles are uniformly distributed around the outer side wall of the circumferential ventilation flow channel.

In the implementation process, since the plurality of first separation baffles and the plurality of second separation baffles are uniformly distributed, a plurality of expansion cavities with identical shapes and sizes can be separated and obtained, and noise with specific frequency is further reduced based on the plurality of expansion cavities, so that the noise reduction effect of the ventilation noise reduction device on the noise with specific frequency is improved.

Optionally, in an embodiment of the present application, a plurality of the first separation baffles are unevenly distributed around an outer sidewall of the ventilation duct; or a plurality of the second separation baffles are unevenly distributed around the outer side wall of the circumferential ventilation channel.

In the implementation process, since the first separation baffles and the second separation baffles are unevenly distributed, a plurality of expansion cavities with inconsistent shapes and sizes can be separated, and noise with different frequencies can be reduced based on the expansion cavities. The ventilation noise reduction device can achieve broadband noise reduction effect while ventilation.

Optionally, in an embodiment of the present application, the number of the circumferential flow channels and the number of the expansion chambers are equal and are each less than or equal to 6.

In the implementation process, the noise reduction amount and the frequency number capable of reducing the noise are integrated to be considered, so that the noise reduction effect of the noise of each frequency is ensured while the noise of multiple frequencies is reduced.

Optionally, in an embodiment of the present application, a cross section of the ventilation duct is circular; the cross section of the annular ventilation flow passage and the annular expansion cavity is annular; the cross-sectional width and length of the annular ventilation flow channel, the cross-sectional width and length of the annular expansion cavity, the distance between the two first separation baffles used for separating each annular flow channel and the distance between the two second separation baffles used for separating each expansion cavity are related to noise frequency required for noise reduction.

In the implementation process, as the shape of a plurality of ventilation openings is circular, the ventilation pipeline is arranged to be a circular pipeline, and the cross sections of the annular ventilation flow channel and the annular expansion cavity are arranged to be circular; so that the ventilation noise reduction device is arranged at the corresponding ventilation opening, and the ventilation is realized and the noise with corresponding frequency is reduced.

In a second aspect, embodiments of the present application provide a scanning apparatus, including: a scanner gantry and at least one ventilation noise reducer as described in any of the first aspects above.

Optionally, in an embodiment of the present application, the ventilation noise reduction device is mounted on the scan gantry.

In the implementation process, the scanning frame is used as a main noise source of the scanning equipment, and the ventilation noise reduction device is arranged on the scanning frame, so that noise generated by the scanning equipment can be reduced better.

Optionally, in an embodiment of the present application, the ventilation noise reduction device is installed at an air outlet on the scan frame.

Adopt this application to provide a ventilation noise reduction device and scanning equipment, because this ventilation noise reduction device includes: the annular expansion cavity comprises a ventilating duct, an annular ventilating flow passage, an annular expansion cavity and at least one opening, wherein the opening is arranged on the adjacent side walls of the annular ventilating flow passage and the annular expansion cavity. The annular ventilation flow passage and the annular expansion cavity can form an expansion cavity based on the opening, acoustic impedance change is caused, so that a phase difference is generated between sound waves which enter the annular expansion cavity along the annular ventilation flow passage and are transmitted forwards along the ventilation pipeline, and mutual interference occurs at a ventilation outlet, so that the purpose of noise reduction is achieved. By adopting the ventilation noise reduction device and the scanning equipment, better noise reduction effect can be obtained. The technical problem that the noise reduction effect is limited due to the existing noise reduction method is solved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a ventilation noise reduction device according to an embodiment of the present application;

FIG. 2 is a schematic circumferential cross-sectional view of a ventilation noise reduction device according to an embodiment of the present disclosure;

FIG. 3 is an axial cross-sectional schematic view of a ventilation noise reduction device according to an embodiment of the present disclosure;

FIG. 4 is a schematic circumferential cross-sectional view of another ventilation noise reduction device provided in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a scanning device according to an embodiment of the present application.

Icon: 01-ventilation noise reduction device; 02-ventilation noise reduction device; 10-ventilation duct; 20-a circumferential ventilation flow channel; 201-a circumferential flow channel; 30-circumferentially expanding the cavity; 301-expanding the chamber; 40-opening; 50-a first separation barrier; 60-a second separation baffle; 03-a scanning device; 031-scan gantry; 032-ventilation noise reduction device.

Detailed Description

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a ventilation noise reduction device 01 according to an embodiment of the present application. Referring to fig. 2 and 3, fig. 2 is a schematic circumferential cross-sectional view of a ventilation noise reduction device provided in an embodiment of the present application, and fig. 3 is a schematic axial cross-sectional view of the ventilation noise reduction device provided in an embodiment of the present application. The ventilation noise reduction device 01 includes: a ventilation duct 10, a circumferential ventilation flow channel 20, a circumferential expansion cavity 30 and at least one opening 40;

the annular ventilation flow passage 20 is arranged on the outer side wall of the ventilation pipeline 10, and the annular expansion cavity 30 is arranged on the outer side wall of the annular ventilation flow passage 20;

at least one opening 40 is provided in adjacent sidewalls of the circumferentially extending vent channel 20 and the circumferentially extending cavity 30.

Wherein, ventilation duct 10 can both be ventilated at both ends, and annular ventilation runner 20 can also be ventilated at both ends. Taking one end of the ventilation noise reduction device 01 as an air inlet and the other end as an air outlet as an example, a part of wind and the transmitted sound waves enter along one end of the ventilation pipeline 10 and then exit along the other end of the ventilation pipeline 10; the other part of the wind and the propagated sound waves enter along one end of the circumferential ventilation flow channel 20, the wind entering along one end of the circumferential ventilation flow channel 20 and the propagated sound waves enter into the circumferential expansion cavity 30 through the opening 40, enter into the circumferential ventilation flow channel 20 from the circumferential expansion cavity 30 through the opening 40, and exit from the other end of the circumferential ventilation flow channel 20, or exit directly from the other end of the circumferential ventilation flow channel 20.

The ventilation duct 10, the circumferential ventilation flow channel 20, and the circumferential expansion cavity 30 may be made of a material with an acoustic impedance greater than a preset acoustic impedance threshold, for example, an acoustic hard material (metal, plastic, etc.), so as to more effectively suppress noise. The cross-sectional shape of the ventilation duct 10 may be circular, square or other. The cross-sectional shape of the annular ventilation flow passage 20 or the annular expansion chamber 30 may be a circular ring, a rectangular ring, or a square ring. The cross-sectional shape of the ventilation duct 10, the circumferential ventilation channel 20 and the circumferential expansion chamber 30 may be selected according to practical application requirements. For example, if the ventilation noise reduction device 01 is applied to a circular ventilation opening, the cross-sectional shape of the ventilation duct 10 may be circular, and the cross-sectional shapes of the circumferential ventilation flow passage 20 and the circumferential expansion chamber 30 may be circular. Fig. 1, 2 and 3 show a case where the cross-sectional shape of the ventilation duct 10 is circular, the cross-sectional shape of the circumferential ventilation flow path 20 is circular, and the cross-sectional shape of the circumferential expansion chamber 30 is circular.

Wherein, the inside wall of the annular ventilation flow passage 20 coincides with the outside wall of the ventilation pipeline 10, and the inside wall of the annular expansion cavity 30 coincides with the outside wall of the annular ventilation flow passage 20. The number of the openings 40 may be 1, 2 or 4, etc., and the number of the openings 40 may affect the noise reduction effect of the ventilation noise reduction device 01, and the specific number thereof may be adjusted according to the actual requirement for the noise reduction effect.

Thus, the ventilation noise reduction device 01 provided by the application comprises: the ventilation duct 10, the annular ventilation flow passage 20, the annular expansion cavity 30 and at least one opening 40, wherein the opening 40 is arranged on the adjacent side walls of the annular ventilation flow passage 20 and the annular expansion cavity 30. The annular ventilation flow passage 20 and the annular expansion cavity 30 can form an expansion cavity based on the opening 40, and acoustic impedance change is caused, so that a phase difference is generated between sound waves which enter the annular expansion cavity 30 along the annular ventilation flow passage 20 and sound waves which propagate forwards along the ventilation pipeline 10, and mutual interference occurs at a ventilation outlet, so that the purpose of noise reduction is achieved. By adopting the ventilation noise reduction device provided by the application, better noise reduction effect can be obtained. The technical problem that the noise reduction effect is limited due to the existing noise reduction method is solved.

Referring to fig. 4, fig. 4 is a schematic circumferential cross-sectional view of another ventilation noise reduction device 02 according to an embodiment of the present application.

In some alternative embodiments, the ventilation noise reduction device 02 further comprises: a plurality of first and second dividing baffles 50 and 60; the first partition plate 50 is configured to partition the circumferential ventilation flow path 20 into a plurality of circumferential flow paths 201; the second separation baffle 60 is further configured to separate the circumferentially expanding cavity 30 into a plurality of expanding chambers 301; wherein, every two annular flow channels 201 are not communicated, and every two expansion chambers 301 are not communicated; at least one opening 40 is provided in each circumferential flow channel 201 and adjacent side walls of the respective expansion chamber 301.

The number of the first partition baffles 50 and the number of the second partition baffles 60 may be equal or unequal, and one circumferential flow channel 201 may correspond to only one expansion chamber 301 or may correspond to a plurality of expansion chambers 301, and the openings 40 are provided on a plurality of adjacent side walls corresponding to each other. The number of the first and second separating baffles 50 and 60 may be selected according to practical applications. The first and second separating baffles 50, 60 may be implemented by selecting a material having an acoustic impedance greater than a predetermined acoustic impedance threshold, such as an acoustically hard material (metal, plastic, etc.), to more effectively suppress noise.

In some alternative embodiments, each circumferential flow channel 201 is in the same plane as the first and second dividing baffles 50, 60 on the same side of the corresponding expansion chamber 301.

In fig. 4, the first partition plate 50 and the second partition plate 60 on the same side of the annular flow channel 201 and the corresponding expansion chamber 301 are shown in the same plane. Because the annular flow channel 201 and the first separation baffle 50 and the second separation baffle 60 on the same side of the corresponding expansion chamber 301 are located on the same plane, the first separation baffle and the corresponding second separation baffle can be implemented by the same baffle, so that the structure of the ventilation noise reduction device can be simplified, and meanwhile, the production process of the ventilation noise reduction device can be simplified, and further, the production cost of the ventilation noise reduction device can be reduced.

In some alternative embodiments, the plurality of first dividing baffles 50 are evenly distributed around the outer sidewall of the ventilation duct 10; and a plurality of second partition plates 60 are uniformly distributed around the outer side wall of the circumferential ventilation channel 20.

Wherein, based on the plurality of first partition baffles 50 and the plurality of second partition baffles 60 which are uniformly distributed, a plurality of expansion chambers with uniform shapes and sizes can be obtained. And noise of specific frequency is reduced based on the plurality of expansion cavities, so that the noise reduction effect of the ventilation noise reduction device on the noise of specific frequency is improved.

In some alternative embodiments, the plurality of first dividing baffles 50 are unevenly distributed about the outer sidewall of the ventilation duct 10; or a plurality of second partition baffles 60 are unevenly distributed about the outer sidewall of the circumferential vent flow channel 20.

Wherein, based on the first partition baffle 50 and the second partition baffle 60 which are unevenly distributed, a plurality of expansion cavities with different shapes and sizes can be obtained, and noise with a plurality of frequencies can be further reduced based on the plurality of expansion cavities.

In some alternative embodiments, the number of circumferential flow channels 201 and expansion chambers 301 are equal and each less than or equal to 6.

Wherein, by defining the annular flow channels 201 and the expansion chambers 301 to be equal in number, the production complexity of the ventilation noise reduction device can be reduced; by limiting the number of the annular flow channels 201 and the expansion chambers 301, noise reduction effect on noise of each frequency can be ensured while noise reduction on noise of multiple frequencies is realized. The specific number of the annular flow channels 201 and the expansion chambers 301 can be determined according to the "number of actual noise reduction frequencies and the actual noise reduction effect requirements of the corresponding noise reduction evaluation rate".

In some alternative embodiments, the ventilation duct 10 is circular in cross-section; the cross section of the annular ventilation flow passage 20 and the annular expansion cavity 30 is annular; the cross-sectional width and length of the annular ventilation flow channel 20, the cross-sectional width and length of the annular expansion chamber 30, the distance between the two first partition baffles 50 separating each annular flow channel 201, and the distance between the two second partition baffles 60 separating each expansion chamber 301 are related to the noise frequency required for noise reduction.

Wherein, since a plurality of air outlets are arranged in a circular shape, the cross section of the ventilation pipeline 10 is in a circular shape; the ventilation noise reduction device with the circular cross sections of the circular ventilation flow passage 20 and the circular expansion cavity 30 can be adapted to the shape of the air outlet in more application scenes, so that the suitability of the ventilation noise reduction device is improved. The "width and length of the cross section of the circumferential ventilation channel 20, the width and length of the cross section of the circumferential expansion chamber 30, the distance between the two first partition plates 50 for partitioning each circumferential channel 201, and the distance between the two second partition plates 60 for partitioning each expansion chamber 301" may be determined according to practical applications.

Specifically, in the case where the "cross-sectional width of the circumferential ventilation flow path 20, the length of the circumferential ventilation flow path 20, the cross-sectional width of the circumferential expansion chamber 30, and the length of the circumferential expansion chamber 30" have been determined, the "shape and size of the circumferential flow path 201 or the expansion chamber 301" may be adjusted by adjusting the position of the first partition baffle 50 or the second partition baffle 60, so that the shape and size of the expansion chamber may be adjusted, and further the noise reduction frequency of the ventilation noise reduction device may be adjusted. In the case that the "distance between the two first partition plates 50 for partitioning each circumferential flow channel 201, the distance between the two second partition plates 60 for partitioning each expansion chamber 301, the cross-sectional width of the circumferential ventilation flow channel 20, the length of the circumferential ventilation flow channel 20" has been determined, the "shape and size of the expansion chamber 301" can be adjusted by adjusting the "cross-sectional width of the circumferential expansion chamber 30 or the length of the circumferential expansion chamber 30", and thus the adjustment of the shape and size of the expansion chamber can be achieved, and further the adjustment of the noise reduction frequency of the ventilation noise reduction device can be achieved. In the case that the "distance between the two first partition plates 50 for partitioning each circumferential flow channel 201, the distance between the two second partition plates 60 for partitioning each expansion chamber 301, the cross-sectional width of the circumferential expansion chamber 30, the length of the circumferential expansion chamber 30" has been determined, the "shape and size of the circumferential flow channel 201" can be adjusted by adjusting the "cross-sectional width of the circumferential ventilation flow channel 20 or the length of the circumferential ventilation flow channel 20", thereby realizing the adjustment of the shape and size of the expansion chamber and further realizing the adjustment of the noise reduction frequency of the ventilation noise reduction device.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a scanning apparatus 03 according to an embodiment of the present application. The scanning device 03 includes: a scanner gantry 031 and at least one ventilation noise reducer 032 as described in any one of the first aspects above.

The scanning device 03 may be, for example, an X-ray machine, for example, a digital X-ray imaging system (Digital Radiography, DR), or an electronic computed tomography (Computed Tomography, CT). The number of the ventilation noise reduction devices 032 included in the scanning apparatus 03 can be determined according to the number of air outlets in actual application, actual requirements for noise reduction effect, and actual cost requirements. In fig. 5, a case is shown in which 3 ventilation noise reduction devices 032 are included in the scanning apparatus 03.

In some alternative embodiments, the ventilation noise reducer 032 is mounted on the scanner gantry 031.

The ventilation and noise reduction device 032 may be installed at an air outlet on the scanner frame 031, or may be installed on a peripheral panel of the scanner frame 031 by a detachable connection device, such as a screw and a nut.

In some alternative embodiments, in embodiments of the present application, the ventilation noise reducer 032 is mounted at an air outlet on the scanner gantry 031.

In the example of CT, the scanner gantry 031 in CT mainly comprises a stator portion and a rotor portion, which are linked together by means of bearings. Wherein the stator part, i.e. the frame fixing part, the ventilation structure is located in the stator part; the rotor part, i.e. the frame rotating part, and the image chain cores of the high-voltage generator, the bulb tube, the detector and the like and the auxiliary control thereof are all positioned on the rotor part. Thus, for CT, the ventilation noise reducer 032 may be specifically mounted to a stator portion of the scanner gantry 031. Taking a CT device with a circular air outlet as an example, the cross section of the ventilation pipeline 10 in the ventilation noise reduction device 032 can be set to be circular; the cross section of the annular ventilation flow passage 20 and the annular expansion chamber 30 may be provided in a circular shape; to match the air outlet shape of the CT device. And the diameter of the common air outlet is larger than 10cm and smaller than 30cm, so the outer diameter of the annular expansion cavity 30 in the ventilation noise reduction device 032 is set to be larger than 10cm and smaller than 30cm so as to be matched with the size of the air outlet of the CT equipment.

It should be noted that fig. 5 shows a case where the ventilation noise reduction device 032 is installed at an air outlet on the scanner housing 031. Through "install ventilation noise reduction device 032 in the air outlet department on scanner frame 031", can realize this ventilation noise reduction device 032 and scanner frame 031's integration preparation, can realize ventilation and noise reduction's function simultaneously based on this ventilation noise reduction device 032, avoided extra ventilation structure, practiced thrift the cost of manufacture of scanning equipment 03.

It should be understood that the scanning apparatus corresponds to the ventilation noise reduction device embodiment described above, and specific functions of the scanning apparatus may be referred to the above description, and detailed descriptions thereof are omitted herein as appropriate to avoid repetition.

The functional modules in the embodiments of the present application may be integrated together to form a single part, or each module may exist alone, or two or more modules may be integrated to form a single part.

The foregoing description is merely an optional implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art may easily think about changes or substitutions within the technical scope of the embodiments of the present application, and the changes or substitutions should be covered in the scope of the embodiments of the present application.

Claims (10)

1. A ventilation noise reduction device, the device comprising:

the device comprises a ventilation pipeline, a circumferential ventilation flow channel, a circumferential expansion cavity and at least one opening;

the annular ventilating duct is arranged on the outer side wall of the ventilating duct, and the annular expansion cavity is arranged on the outer side wall of the annular ventilating duct;

the at least one opening is arranged on the adjacent side walls of the annular ventilation flow passage and the annular expansion cavity.

2. The apparatus of claim 1, wherein the apparatus further comprises: a plurality of first and second dividing baffles;

the first separation baffle is configured to separate the annular ventilation flow passage into a plurality of annular flow passages;

the second separation baffle is further configured to separate the circumferential expansion cavity into a plurality of expansion chambers;

wherein, every two annular flow passages are not communicated with each other, and every two expansion chambers are not communicated with each other; the at least one opening is arranged on the adjacent side wall of each annular flow passage and the corresponding expansion chamber.

3. The apparatus of claim 2, wherein each of the circumferential flow channels is coplanar with the first and second dividing baffles on the same side of the respective expansion chamber.

4. A device according to claim 2 or 3, wherein a plurality of the first dividing baffles are evenly distributed around the outer side wall of the ventilation duct; and a plurality of the second partition baffles are uniformly distributed around the outer side wall of the circumferential ventilation flow channel.

5. A device according to claim 2 or 3, wherein a plurality of the first dividing baffles are unevenly distributed around the outer side wall of the ventilation duct; or a plurality of the second separation baffles are unevenly distributed around the outer side wall of the circumferential ventilation channel.

6. The device of claim 2, wherein the number of circumferential flow channels and the expansion chamber are equal and each less than or equal to 6.

7. The apparatus of claim 2, wherein the ventilation duct is circular in cross-section;

the cross section of the annular ventilation flow passage and the annular expansion cavity is annular;

the length and the cross-section width of the annular ventilation flow channel, the length and the cross-section width of the annular expansion cavity, the distance between the two first separation baffles used for separating each annular flow channel and the distance between the two second separation baffles used for separating each expansion cavity are related to noise frequency required to reduce noise.

8. A scanning device, the device comprising: a scanner gantry and at least one ventilation noise reducer as claimed in any one of claims 1 to 7.

9. The apparatus of claim 8, wherein the ventilation noise reducer is mounted on the scan gantry.

10. The apparatus of claim 9, wherein the ventilation noise reduction device is mounted at an air outlet on the scanner frame.