Active noise cancellation device for ventilation ducts

Abstract

The application discloses a kind of active noise cancellation device for ventilation duct, including ventilation duct and installation plate being arranged on ventilation duct, the ventilation duct includes first pipe and second pipe, the opposite side of the outer surface of first pipe and second pipe is all welded and fixed with butt joint frame, the both sides of installation plate are all penetrated and slidably installed with first L-shaped positioning frame, and the application relates to noise control technical field.The active noise cancellation device for ventilation duct provides the abutment of the abutment of two butt joint frames with the setting of two first L-shaped positioning frames, first rubber sleeve, first butt joint groove, installation plate and first fastening bolt, and provides fixing condition for detection box, to ensure that active noise eliminator is effectively used in ventilation duct, and cooperate with the setting of telescopic air cylinder, noise reduction frame and cover plate, when ventilation duct is not used, active noise eliminator can be isolated and protected by cover plate, to avoid the influence of dust on active noise eliminator.

Description

Technical Field

[0001] This invention relates to the field of noise control technology, specifically to an active silencing device for ventilation ducts. Background Technology

[0002] Suppressing low-frequency noise in ventilation ducts has always been difficult because the low-frequency sound absorption efficiency of general sound-absorbing materials is not high, resonant sound-absorbing structures often occupy a large volume and the sound absorption frequency band is not very wide, and the low-frequency sound insulation of general sound insulation structures is also very small.

[0003] The basic principle of an active silencer is to use electronic devices to generate a sound wave with the same magnitude but opposite phase as the original sound pressure in the original sound field, so that it cancels out the original sound field within a certain range. An active silencer is a set of instruments and devices, mainly composed of a microphone, amplifier, phase shifter, power amplifier and loudspeaker.

[0004] An active ventilation silencing device, as described in application number 201610049154.9, integrates sensors, controllers, and actuators into a single unit to construct an active ventilation silencing device. It can be flexibly installed on the duct wall to eliminate noise within the ventilation duct system, providing high noise reduction for applications with high requirements for ventilation noise.

[0005] Based on the above information, it can be seen that when installing active silencers, the process often involves simply using bolts to fix the silencer to the ventilation duct. The ventilation duct is usually made of stainless steel with a thickness of 0.5mm to 4mm. Using bolts for connection can easily lead to unstable installation and gas leakage, especially for thinner ventilation ducts. Furthermore, when not in use for a long time, dust can easily accumulate on the active silencer, affecting its normal operation. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides an active silencer for ventilation ducts, which solves the problem that directly fixing the active silencer to a thin ventilation duct with bolts can easily lead to unstable installation and gas leakage. Furthermore, when not in use for a long time, the active silencer is less prone to dust accumulation, which can affect its normal operation.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution: an active silencing device for ventilation ducts, comprising a ventilation duct and an mounting plate disposed on the ventilation duct, wherein the ventilation duct includes a first duct and a second duct, and a docking frame is welded and fixed on opposite sides of the outer surfaces of the first duct and the second duct, and a first L-shaped positioning frame is slidably mounted through both sides of the mounting plate, and the first L-shaped positioning frame and the mounting plate are fixedly connected by a first fastening bolt, and a first rubber sleeve is fixedly connected to the surface of the first L-shaped positioning frame, and a first docking groove adapted to the docking frame is opened on the surface of the first rubber sleeve;

[0010] A detection box is fixedly connected to the bottom of the mounting plate, a telescopic cylinder is fixedly connected to the bottom of the detection box, a noise reduction frame is fixedly connected to the telescopic end of the telescopic cylinder, an active silencer is fixedly connected to the top of the noise reduction frame, and a cover plate is fixedly connected to the top of the active silencer. The first pipe, the second pipe, and the two docking frames are connected to the top of the mounting plate through a mounting groove, and the noise reduction frame and the cover plate are slidably connected to the inner surface of the mounting groove.

[0011] The present invention is further configured such that: a second L-shaped positioning frame is slidably mounted through the top of each of the two first L-shaped positioning frames, and the second L-shaped positioning frame and the first L-shaped positioning frame are fixedly connected by a second fastening bolt;

[0012] The surface of the second L-shaped positioning frame is provided with several positioning holes, and the positioning holes are used in conjunction with the second fastening bolt.

[0013] The present invention is further configured such that: a lead screw is threaded through and installed on the top of the second L-shaped positioning frame; a knob is fixedly connected to the top of the lead screw; an L-shaped plate is rotatably installed on the bottom of the lead screw via a bearing; and a second rubber sleeve is fixedly connected to the surface of the L-shaped plate; and a second docking groove adapted to the docking frame is opened on the surface of the second rubber sleeve.

[0014] The present invention is further configured such that: a front sensor is fixedly installed at the bottom of the inner cavity of the first pipe, and an error sensor is fixedly installed at the bottom of the inner cavity of the second pipe;

[0015] The front sensor is used to detect the noise intensity on the incoming wind side;

[0016] The error sensor is used to detect the noise intensity on the air outlet side.

[0017] The present invention is further configured such that: both sides of the mounting plate are provided with a first through groove adapted to the first L-shaped positioning frame;

[0018] The top of the first L-shaped positioning frame is provided with a second through groove that is adapted to the second L-shaped positioning frame.

[0019] The present invention is further configured such that: both sides of the bottom of the mounting plate are fixedly connected with guide tubes that cooperate with the first fastening bolts.

[0020] The present invention is further configured such that: two sound-absorbing cotton boards are fixedly connected to the top of the mounting plate, and the top of both sound-absorbing cotton boards are in contact with the bottom of the ventilation duct;

[0021] The two sound-absorbing cotton boards have slots on opposite sides that are adapted to the noise reduction frame.

[0022] The present invention is further configured such that: a notched gasket is provided between the two docking frames, and a noise-reducing gasket is integrally formed on the inner surface of the notched gasket, the inner surface of the noise-reducing gasket is arc-shaped, and the outer surface of the noise-reducing gasket is in contact with the inner surfaces of the first pipe and the second pipe.

[0023] (III) Beneficial Effects

[0024] This invention provides an active noise reduction device for ventilation ducts. It has the following beneficial effects:

[0025] (1) The present invention provides a limit for the docking of the two docking frames by setting two first L-shaped positioning frames, a first rubber sleeve, a first docking groove, a mounting plate and a first fastening bolt, while also providing a fixing condition for the detection box. This ensures that the active silencer can be used effectively in the ventilation duct. In addition, with the setting of telescopic cylinder, noise reduction frame and cover plate, when the ventilation duct is not in use, the cover plate can be used to isolate and protect the active silencer, avoiding the influence of dust on the active silencer.

[0026] (2) The present invention achieves circumferential fixation between the device and the ventilation duct by setting the second L-shaped positioning frame, the second fastening bolt and several positioning holes, which avoids the detection box from falling off during use. At the same time, the setting of the screw, knob, L-shaped plate, second rubber sleeve and second docking groove ensures the stability of the connection between the device and the ventilation duct and avoids resonance during the noise reduction process.

[0027] (3) The present invention achieves effective sealing of the connection gap between the first pipe and the second pipe through the cooperation of notched gasket and noise reduction gasket, and enhances the noise reduction effect through noise reduction gasket. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the external structure obtained after assembly of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the first pipe, the second pipe, the docking frame, the notched washer, and the noise reduction washer of the present invention.

[0030] Figure 3This is a schematic diagram of the structure of the mounting plate, the first L-shaped positioning frame, and the second L-shaped positioning frame of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the mounting plate and the second L-shaped positioning frame of the present invention;

[0032] Figure 5 This is a schematic diagram showing the connection of the mounting plate, telescopic cylinder, noise reduction frame, active muffler, and cover plate structure of the present invention.

[0033] In the diagram, 1. Ventilation duct; 2. Mounting plate; 3. First duct; 4. Second duct; 5. Docking frame; 6. First L-shaped positioning frame; 7. First fastening bolt; 8. First rubber sleeve; 9. First docking groove; 10. Detection box; 11. Telescopic cylinder; 12. Noise reduction frame; 13. Active silencer; 14. Cover plate; 15. Mounting groove; 16. Second L-shaped positioning frame; 17. Second fastening bolt; 18. Positioning hole; 19. Lead screw; 20. Knob; 21. L-shaped plate; 22. Second rubber sleeve; 23. Second docking groove; 24. Front sensor; 25. Error sensor; 26. First through groove; 27. Second through groove; 28. Guide tube; 29. ​​Sound-absorbing cotton board; 30. Groove opening; 31. Notched washer; 32. Noise reduction washer. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Please see Figure 1-5 The present invention provides the following two technical solutions:

[0036] Example 1

[0037] An active noise reduction device for ventilation ducts includes a ventilation duct 1 consisting of a first duct 3 and a second duct 4, and a mounting plate 2. A docking frame 5 is welded and fixed to the opposite side of the outer surface of the first duct 3 and the second duct 4. A front sensor 24 is fixedly installed at the bottom of the inner cavity of the first duct 3. The front sensor 24 is used to detect the noise intensity on the incoming air side. An error sensor 25 is fixedly installed at the bottom of the inner cavity of the second duct 4. The error sensor 25 is used to detect the noise intensity on the outgoing air side. Both the front sensor 24 and the error sensor 25 transmit the collected noise intensity information to the central processing unit described below.

[0038] As a preferred embodiment, in order to ensure the sealing effect of the connection between the first pipe 3 and the second pipe 4, a notched gasket 31 is provided between the two mating frames 5, and a noise-reducing gasket 32 ​​is integrally formed on the inner surface of the notched gasket 31. The inner surface of the noise-reducing gasket 32 ​​is arc-shaped, and the outer surface of the noise-reducing gasket 32 ​​is in contact with the inner surfaces of the first pipe 3 and the second pipe.

[0039] As a preferred embodiment, in order to ensure the installation stability of the mounting plate 2, a first L-shaped positioning frame 6 is slidably installed through both sides of the mounting plate 2. A first through groove 26 adapted to the first L-shaped positioning frame 6 is opened on both sides of the mounting plate 2. The first L-shaped positioning frame 6 and the mounting plate 2 are fixedly connected by a first fastening bolt 7. Guide cylinders 28 that cooperate with the first fastening bolt 7 are fixedly connected to both sides of the bottom of the mounting plate 2. A first rubber sleeve 8 is fixedly connected to the surface of the first L-shaped positioning frame 6. A first docking groove 9 adapted to the docking frame 5 is opened on the surface of the first rubber sleeve 8.

[0040] As a preferred embodiment, to facilitate active noise reduction, a detection box 10 is fixedly connected to the bottom of the mounting plate 2, and a telescopic cylinder 11 is fixedly connected to the bottom of the detection box 10. The telescopic cylinder 11 is electrically connected to an external power source and controlled by a central processing unit. A noise reduction frame 12 is fixedly connected to the telescopic end of the telescopic cylinder 11, and an active silencer 13 is fixedly connected to the top of the noise reduction frame 12. A cover plate 14 is fixedly connected to the top of the active silencer 13. The first pipe 3, the second pipe 4, and the two docking frames 5 are connected to the top of the mounting plate 2 through a mounting groove 15, and both the noise reduction frame 12 and the cover plate 14 are slidably connected to the inner surface of the mounting groove 15.

[0041] As explained in detail, after the noise intensity information collected by the front sensor 24 is transmitted to the central processing unit, the central processing unit determines that the noise intensity information has reached the required noise reduction standard. Then, it controls the telescopic cylinder 11 to extend. The telescopic cylinder 11 pushes the noise reduction frame 12 to move the active muffler 13 into the ventilation duct 1, emitting noise with the same but opposite intensity as the noise. The noise intensity information collected by the error sensor 25 is transmitted to the central processing unit. The central processing unit adjusts the noise intensity emitted by the active muffler 13 according to the noise intensity information collected by the error sensor 25. Specifically, when the noise intensity collected by the error sensor 25 is higher than the noise intensity corresponding to the noise reduction standard, the noise intensity emitted by the active muffler 13 is increased. Conversely, when the noise intensity collected by the error sensor 25 is lower than the noise intensity corresponding to the noise reduction standard, the current noise intensity emitted by the active muffler 13 is maintained.

[0042] To further explain, two sound-absorbing cotton panels 29 are fixedly connected to the top of the mounting plate 2, and the tops of the two sound-absorbing cotton panels 29 are in contact with the bottom of the ventilation duct 1. A groove 30 adapted to the noise reduction frame 12 is provided on the opposite side of the two sound-absorbing cotton panels 29.

[0043] In this embodiment, while ensuring convenient installation of the device, it can also ensure an effective noise reduction effect on the ventilation duct 1.

[0044] Example 2

[0045] This embodiment is an improvement on the previous embodiment. An active silencing device for ventilation ducts further includes two second L-shaped positioning frames 16, the tops of which are both through and slidably mounted. The top of the first L-shaped positioning frame 6 is provided with a second through groove 27 that is adapted to the second L-shaped positioning frame 16. The second L-shaped positioning frame 16 and the first L-shaped positioning frame 6 are fixedly connected by a second fastening bolt 17. In order to achieve effective positioning of ventilation ducts 1 of different sizes, a plurality of positioning holes 18 are provided on the surface of the second L-shaped positioning frame 16, and the positioning holes 18 are used in conjunction with the second fastening bolt 17.

[0046] As a preferred embodiment, in order to ensure the stability of the connection between the first L-shaped positioning frame 6 and the ventilation duct 1, a lead screw 19 is threaded through and installed on the top of the second L-shaped positioning frame 16. A knob 20 is fixedly connected to the top of the lead screw 19, and an L-shaped plate 21 is rotatably installed at the bottom of the lead screw 19 through a bearing. A second rubber sleeve 22 is fixedly connected to the surface of the L-shaped plate 21, and a second docking groove 23 that matches the docking frame 5 is opened on the surface of the second rubber sleeve 22.

[0047] The advantage of Example 2 over Example 1 is that it can further ensure the stability of the device after installation and avoid the device from falling off.

[0048] In use, move the two first L-shaped positioning frames 6 to both sides of the ventilation duct 1, so that the first docking groove 9 fits around the outer periphery of the two docking frames 5, squeeze the first L-shaped positioning frames 6 to make them in close contact with the ventilation duct 1, and then tighten the first fastening bolt 7 to make the mounting plate 2 and the two first L-shaped positioning frames 6 stably limit the ventilation duct 1. In order to strengthen the limit, directly tighten the second fastening bolt 17 so that the second fastening bolt 17 squeezes the surface of the ventilation duct 1.

[0049] To improve assembly stability, loosen the second fastening bolt 17, insert the second L-shaped positioning bracket 16 into the second through groove 27, and bring the second rubber sleeve 22 close to the ventilation duct 1. Then tighten the second fastening bolt 17 so that the second fastening bolt 17 passes through the corresponding positioning hole 18 and presses against the surface of the ventilation duct 1. Then turn the knob 20, which drives the lead screw 19 to rotate. The lead screw 19 drives the L-shaped plate 21 to make the second rubber sleeve 22 fit tightly against the surface of the ventilation duct 1. After the device installation is completed;

[0050] After the noise intensity information collected by the front sensor 24 is transmitted to the central processing unit, the central processing unit determines that the noise intensity information has reached the required noise reduction standard. Then, it controls the telescopic cylinder 11 to extend. The telescopic cylinder 11 pushes the noise reduction frame 12 to move the active muffler 13 into the ventilation duct 1, emitting noise with the same but opposite intensity as the noise. The noise intensity information collected by the error sensor 25 is transmitted to the central processing unit. The central processing unit adjusts the noise intensity emitted by the active muffler 13 according to the noise intensity information collected by the error sensor 25. Specifically, when the noise intensity collected by the error sensor 25 is higher than the noise intensity corresponding to the noise reduction standard, the noise intensity emitted by the active muffler 13 is increased. Conversely, when the noise intensity collected by the error sensor 25 is lower than the noise intensity corresponding to the noise reduction standard, the current noise intensity emitted by the active muffler 13 is maintained.

Claims

1. An active silencing device for ventilation ducts, comprising a ventilation duct (1) and a mounting plate (2) disposed on the ventilation duct (1), characterized in that: The ventilation duct (1) includes a first duct (3) and a second duct (4). A docking frame (5) is welded and fixed on the opposite side of the outer surface of the first duct (3) and the second duct (4). A first L-shaped positioning frame (6) is slidably installed through both sides of the mounting plate (2). The first L-shaped positioning frame (6) and the mounting plate (2) are fixedly connected by a first fastening bolt (7). A first rubber sleeve (8) is fixedly connected to the surface of the first L-shaped positioning frame (6). A first docking groove (9) adapted to the docking frame (5) is opened on the surface of the first rubber sleeve (8). The bottom of the mounting plate (2) is fixedly connected to a detection box (10), the bottom of the detection box (10) is fixedly connected to a telescopic cylinder (11), the telescopic end of the telescopic cylinder (11) is fixedly connected to a noise reduction frame (12), the top of the noise reduction frame (12) is fixedly connected to an active silencer (13), the top of the active silencer (13) is fixedly connected to a cover plate (14), the first pipe (3), the second pipe (4) and the two docking frames (5) are connected to the top of the mounting plate (2) through a mounting groove (15), and the noise reduction frame (12) and the cover plate (14) are slidably connected to the inner surface of the mounting groove (15); The top of each of the two first L-shaped positioning frames (6) is slidably mounted with a second L-shaped positioning frame (16), and the second L-shaped positioning frame (16) and the first L-shaped positioning frame (6) are fixedly connected by a second fastening bolt (17); The surface of the second L-shaped positioning frame (16) is provided with a plurality of positioning holes (18), and the positioning holes (18) are used in conjunction with the second fastening bolt (17); The top of the second L-shaped positioning frame (16) is threaded with a lead screw (19), the top of the lead screw (19) is fixedly connected with a knob (20), the bottom of the lead screw (19) is rotatably mounted with an L-shaped plate (21) through a bearing, and the surface of the L-shaped plate (21) is fixedly connected with a second rubber sleeve (22), and the surface of the second rubber sleeve (22) is provided with a second docking groove (23) that is compatible with the docking frame (5).

2. The active silencing device for ventilation ducts according to claim 1, characterized in that: A front sensor (24) is fixedly installed at the bottom of the inner cavity of the first pipe (3), and an error sensor (25) is fixedly installed at the bottom of the inner cavity of the second pipe (4). The front sensor (24) is used to detect the noise intensity on the windward side; The error sensor (25) is used to detect the noise intensity on the air outlet side.

3. The active silencing device for ventilation ducts according to claim 1, characterized in that: Both sides of the mounting plate (2) are provided with a first through groove (26) that is compatible with the first L-shaped positioning frame (6). The top of the first L-shaped positioning frame (6) is provided with a second through groove (27) that is compatible with the second L-shaped positioning frame (16).

4. The active silencing device for ventilation ducts according to claim 1, characterized in that: The bottom sides of the mounting plate (2) are fixedly connected with guide tubes (28) that cooperate with the first fastening bolt (7).

5. The active silencing device for ventilation ducts according to claim 1, characterized in that: The top of the mounting plate (2) is fixedly connected to two sound-absorbing cotton boards (29), and the top of both sound-absorbing cotton boards (29) is in contact with the bottom of the ventilation duct (1). The two sound-absorbing cotton boards (29) have slots (30) on opposite sides that are adapted to the noise reduction frame (12).

6. The active silencing device for ventilation ducts according to claim 1, characterized in that: A notched gasket (31) is provided between the two docking frames (5), and a noise reduction gasket (32) is integrally formed on the inner surface of the notched gasket (31). The inner surface of the noise reduction gasket (32) is arc-shaped, and the outer surface of the noise reduction gasket (32) is in contact with the inner surfaces of the first pipe (3) and the second pipe.

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