CN103670602A - Three-layer series micro-perforated pipe muffler - Google Patents

Abstract

The invention relates to the field of mufflers, and specifically provides a three-layer series-connected micro-perforated tube muffler, which includes a muffler main body, an inlet end and an exhaust end. The main body of the muffler adopts a three-layer micro-perforated tube structure for noise reduction, the aperture is 0.1-0.5 mm, and the porosity is less than 5%. There are gaps between the three-layer micro-perforated tubes and no filling material. The porosity and the volume of each cavity are different, so as to realize the elimination of noise in different frequency bands. When the muffler is working, the airflow flows directly through the pipeline, and the back pressure loss is small. The exhaust muffler has the advantages of simple structure, convenient processing, low cost, high temperature resistance, corrosion resistance, air flow impact resistance and long service life of the pure metal structure. It has a good noise reduction effect in the whole spectrum range, especially in the high frequency band, and the noise reduction amount reaches 15-25dB.

Description

A three-layer series micro-perforated tube muffler

technical field

The invention relates to the field of mufflers, and specifically provides a muffler with three-layer series micro-perforated tubes used in exhaust and noise reduction of air suction pumps.

Background technique

The noise when the air pump is working is mainly composed of gas flow noise and mechanical component motion noise, and the noise frequency range is wide. While eliminating the high frequency part of the gas flow noise, the middle and low frequency part of the mechanical noise cannot be ignored. The traditional resistive muffler needs to be filled with sound-absorbing materials to achieve the purpose of noise reduction; the resistive muffler achieves the purpose of noise reduction through complex structure to generate impedance mismatch. The former is not suitable for working in a relatively closed environment, because the sound-absorbing material will inevitably float in the studio under the long-term scouring of the exhaust flow, which will adversely affect the health of personnel; the long-term scouring reduces the sound-absorbing material in the muffler , the noise reduction effect is reduced, so its service life is not long. Resistant mufflers need to use complex cavity or resonance cavity design, so that the volume of the muffler is larger and the exhaust back pressure is larger.

Contents of the invention

The technical problem to be solved by the present invention is to provide a long-term use in a relatively closed working environment, which has high temperature resistance, corrosion resistance, airflow impact resistance, long service life, good noise reduction effect, small exhaust pressure loss, and structural A simple, easy-to-fabricate, low-cost muffler capable of muffled sound over a wide frequency band including low, mid, and high frequencies.

In order to solve the problems of the technologies described above, the technical solution of the present invention is as follows:

A three-layer micro-perforated tube muffler in series, comprising an air inlet (7), an exhaust end (8) and a muffler body between the air inlet (7) and the exhaust end (8), characterized in that: The main body of the above-mentioned muffler is composed of four parts coaxially socketed from the outside to the inside, the shell (5), the micro-perforated outer tube (4), the micro-perforated middle tube (3), and the micro-perforated inner tube (2), and the micro-perforated outer tube ( 4), the micro-perforated middle tube (3), and the micro-perforated inner tube (2) are covered with micro-holes, and each micro-hole is a straight-through micro-hole perpendicular to the central axis of the four parts; each tube layer of the muffler body There are cavities between the micro-perforated outer tube (4) and the shell (5), and there is no filling material in each cavity; the air inlet (7) and the main body of the muffler are sealed and connected by the front end cover (1), The exhaust end (8) is closed and connected to the main body of the muffler through the rear end cover (6). The center of the front end cover (1) and the rear end cover (6) is provided with a central through hole equal in diameter to the micro-perforated inner tube (2). The diameter of the micro-perforated inner tube (2) is equal to that of the inlet port (7) and the exhaust port (8), and it is directly connected to the inlet port (7) and the exhaust port (8), or the micro-perforated inner tube (2) One end directly protrudes from the central through hole of the rear end cover (6) to form an exhaust end (8).

According to the above technical solution, the cavity depths between the tube layers of the muffler main body and between the micro-perforated outer tube (4) and the shell (5) are not equal.

According to the above technical solution, the cross-sections of the shell (5) of the muffler main body, the micro-perforated outer tube (4), the micro-perforated middle tube (3), and the micro-perforated inner tube (2) are all circular; or the outer shell (5), The cross-sections of the micro-perforated outer tube (4) and the micro-perforated middle tube (3) are square, while the cross-section of the micro-perforated inner tube (2) is circular.

According to the above technical scheme, the pore diameter and porosity of the micropores of each tube layer are different.

According to the above technical scheme, the diameter of the micropores in each tube layer is 0.1-0.5mm, and the porosity is less than 5%.

According to the above technical proposal, the shell (5) of the muffler main body and each pipe layer are made of metal.

According to the above technical solution, the pipe wall thicknesses of the pipe layers of the muffler main body are the same or different.

The present invention utilizes a smaller volume to achieve a greater noise reduction effect. The main body of the muffler adopts three layers of micro-perforated tubes. There is a cavity between each layer of micro-perforated tubes. There is no filling material in the cavity. , The depth of each cavity is reasonably matched to realize the elimination of noise in different frequency bands. When the muffler is working, the airflow flows directly through the pipeline, and the back pressure loss is small. When working, the airflow flows in from the air inlet on the front cover, radially flows through the cavity layer between the shell and the three-layer micro-perforated tube in series, and passes through the three-layer micro-perforated tube to eliminate the sound from the exhaust port on the rear end cover. discharge. When the air flow passes through the muffler, the micropore diameter and porosity on the tube wall are small, the surface is relatively smooth, and the resistance to the air flow is small. The main gas flows along the axis of the tube, so the pressure loss is small. When the sound wave passes through the micropores, the sound energy is converted into heat energy due to the friction between the air and the micropores, so as to achieve the purpose of noise reduction. At the same time, through optimization calculation, it is found that in the microporous tube structure, the pore size will affect the frequency of noise reduction; under the same pore size, the frequency of noise reduction will move to high frequency when the porosity increases; changing the depth of the cavity means changing the micro-perforation of each layer The distance between the tubes can increase the width of the anechoic frequency band and increase the amount of anechoic noise. In the three-layer micro-perforated tube structure, the rational design of the porosity, aperture and cavity depth of each layer of perforated plates can obtain wider noise reduction frequency and greater noise reduction amount, and the noise reduction amount can reach 15dB.

As a modified design of the present invention, two-layer or four-layer series micro-perforated pipe mufflers can be designed, but compared with two layers, the three-layer structure of the present invention passes through the porosity, aperture and cavity depth of each layer of perforated plates Reasonable matching can obtain a wider frequency band of noise reduction frequency and greater noise reduction, while the structure of more than four layers of micro-perforated tubes in series has basically no noise reduction effect.

The beneficial effects of the present invention are: without setting a buffer chamber, the use of three layers of micro-perforated tubes in series can achieve the noise reduction effect of a wider frequency band, which is smaller than the volume of the traditional impedance structure muffler; The gas end is directly connected, and the air flow has no turning and buffering, which minimizes the flow resistance when the air flow passes through the muffler; the pure metal structure can withstand high temperature, corrosion resistance, air impact resistance, and long service life; no sound-absorbing cotton is used. Flammable and easy to inhale, which ensures the safety of people when the muffler works in a relatively closed environment.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing, in the accompanying drawing:

Fig. 1 is the structure schematic diagram of three layers of micro-perforated tube muffler of the present invention;

Fig. 2 is the A-A sectional view of Fig. 1;

Fig. 3 is a partial schematic view of the micropore arrangement of the micropore inner tube;

Fig. 4 is a partial schematic view of the micropore arrangement of the tube in the micropore;

Fig. 5 is a partial schematic diagram of the micropore arrangement of the microporous outer tube;

The corresponding marks in the figure are as follows: front cover 1, microporous inner tube 2, microporous inner tube 3, microporous outer tube 4, shell 5, rear end cover 6, air inlet 7, exhaust 8, flow channel I9 , Cavity II 10, Cavity III 11, Cavity IV 12; Micropore 13 of the micropore inner tube, micropore 14 of the micropore middle tube, and micropore 15 of the micropore outer tube.

Detailed ways

Example 1:

As shown in Fig. 1-5, the three-layer micro-perforated tube muffler in series of the present invention includes a metal shell 5, and the two ends of the shell 5 are respectively a front end cover 1 and a rear end cover 6, and the cross section of the muffler is circular. To the outside are the microporous inner tube 2, the microporous middle tube 3, the microporous outer tube 4, and the muffler shell 5.

The muffler shell 5 is cylindrical; the air intake end and the exhaust end are directly connected through the muffler shell, and the air intake end and the exhaust end are located at the center of the two ends of the cylinder; The three-layer micro-perforated tube divides the inner space of the shell into flow channel I9, cavity II10, cavity III11, and cavity IV12; the three-layer micro-perforated tube is cylindrical, and the micro-porous inner tube 2 is connected The air end 7 and the exhaust end 8 have the same diameter, and are directly connected to the air intake end and the exhaust end. The microporous outer tube 4 is located between the microporous inner tube 2 and the shell 5, and divides the cavity between the microporous inner tube 2 and the shell 5 into two parts with different volumes. The microporous inner tube 3 is located between the microporous outer tube 4 and the microporous inner tube 2, and divides the cavity between the microporous outer tube 4 and the micropore inner tube 2 into two parts of unequal volume along the axial direction of the shell. ; The microporous inner tube 2, the microporous middle tube 3, and the microporous outer tube 4 are provided with micropores of different diameters, and the micropores on the three-layer microporous tubes are arranged in different ways.

The microporous inner tube 2 , the microporous inner tube 3 and the microporous outer tube 4 are made by punching metal sheets of the same thickness. As shown in Figure 3-5, the diameter of the microholes 13 in the microporous inner tube is 0.5mm, the distance between the adjacent microholes 13 along the axial direction of the muffler is 1.6mm, and there are two adjacent rows along the circumferential direction of the cross section of the muffler The hole center distance between the microholes 13 is 1mm. The diameter of the micropores 14 in the microhole is 0.8 mm, the distance between the centers of the adjacent microholes 14 along the longitudinal direction of the muffler is 1.8 mm, and the distance between the centers of the two adjacent microholes 14 along the circumferential direction of the cross section of the muffler is 1.8 mm. The diameter of the micropores 15 of the microporous outer tube is 1 mm, the distance between the centers of the adjacent micropores 15 along the longitudinal direction of the muffler is 2 mm, and the distance between the centers of the two adjacent rows of micropores 15 along the circumferential direction of the cross section of the muffler is 2.6 mm, that is, different tube layers The porosity and pore size are different.

Example 2:

It is basically the same as Figure 1 and Figure 3-5 of Embodiment 1, except that the cross section of the muffler housing 5 is square, the cross section of the microporous outer tube 4 is square, and the cross section of the microporous inner tube 3 is square , the microporous inner tube 2 has a circular cross section.

In other embodiments not listed in the present invention, the cross-sectional shape of the muffler shell 5, the microporous outer tube 4, and the microporous inner tube 3 can also be changed to an isosceles polygon, such as a rhombus or a pentagon.

In the above-mentioned embodiment, when the three-layer micro-perforated tube muffler in series of the present invention is working, the airflow flows in from the air inlet 7 on the front cover 1, flows through the shell 5 and the three-layer series micro-perforated tubes 2, 3, 4, and passes through three The layer of micro-perforated pipe is discharged from the exhaust port 8 on the rear end cover 6 after the noise is eliminated. The airflow does not have any turning and buffering process when passing through the muffler, thereby reducing the exhaust back pressure to the greatest extent.

The above description is only preferred of the present invention and is not intended to limit the present invention. Those skilled in the art can make various changes to the present invention without departing from the spirit and scope of the present invention, and all these changes should belong to the appended rights of the present invention the scope of protection required. the

Claims (7)

1. one kind three layers series connection micropunch muffler pipe, comprise inlet end (7), exhaust end (8) and the muffler body between inlet end (7) and exhaust end (8), it is characterized in that: described muffler body is managed (3) from outside to inside in shell (5), micropunch outer tube (4), micropunch, micropunch inner tube (2) four parts are coaxially socketed and form, and in micropunch outer tube (4), micropunch, on pipe (3), micropunch inner tube (2) tube wall, be covered with micropore, and each micropore is the straight-through micropore perpendicular to tetrameric central axis; Between each pipe layer of muffler body and be that cavity and each cavity are all without any packing material between micropunch outer tube (4) and shell (5); Between inlet end (7) and muffler body, by front cover (1) sealing, be connected, between exhaust end (8) and muffler body, by rear end cover (6) sealing, be connected, front cover (1) and rear end cover (6) center arrange the central through bore with micropunch inner tube (2) equal diameters, micropunch inner tube (2) and inlet end (7) and exhaust end (8) equal diameters, direct conducting inlet end (7) and exhaust end (8), or one end of micropunch inner tube (2) is directly stretched out and is formed exhaust end (8) from rear end cover (6) central through bore.

2. three layers of series connection micropunch muffler pipe according to claim 1, is characterized in that: between each pipe layer of muffler body and the cavity depth between micropunch outer tube (4) and shell (5) all unequal.

3. three layers of series connection micropunch muffler pipe according to claim 1 and 2, is characterized in that: in the shell of muffler body (5) and micropunch outer tube (4), micropunch, the cross section of pipe (3), micropunch inner tube (2) is circle; Or in shell (5), micropunch outer tube (4) and micropunch, the cross section of pipe (3) is square, and the cross section of micropunch inner tube (2) is circular.

4. three layers of series connection micropunch muffler pipe according to claim 3, is characterized in that: aperture and the porosity ratio of the micropore of each pipe layer are all not identical.

5. according to three layers of series connection micropunch muffler pipe described in claim 1 or 2 or 4, it is characterized in that: the aperture of the micropore of each pipe layer is 0.1-0.5mm, and porosity ratio is less than 5%.

6. three layers of series connection micropunch muffler pipe according to claim 5, is characterized in that: the shell of muffler body (5) and each pipe layer are metal material.

7. according to three layers of series connection micropunch muffler pipe described in claim 1 or 2 or 4 or 6, it is characterized in that: the pipe thickness of each pipe layer of muffler body is identical or different.

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