A device and method for eliminating whistling in a respiratory mask test

Abstract

The application discloses a kind of whistling sound elimination device and method in respiratory mask test, including the test head mould for conducting airflow, the respiratory mask being connected with air steel bottle and being arranged outside test head mould, artificial lung for simulating human lung breathing is arranged below test head mould, transmission mechanism that artificial lung can be stretched or compressed so that artificial lung dilatation or contraction is arranged below artificial lung, elimination mechanism that can eliminate whistling sound generated when transmission mechanism stretches or compresses artificial lung, transmission mechanism is connected with elimination mechanism, test head mould is communicated with artificial lung.The application increases the tension of the bottom of artificial lung by setting elimination mechanism, thereby increasing inertia when transmission mechanism stretches or compresses artificial lung, changing resonance point, eliminating resonance, and then improving the accuracy and efficiency of respiratory mask test.

Description

Technical Field

[0001] This invention relates to the field of fire equipment testing technology, and in particular to a device and method for eliminating whistling noise during breathing mask testing. Background Technology

[0002] Breathing masks are essential equipment for firefighters entering and exiting fire scenes and for emergency firefighting. The stable operation of these masks is crucial to their lives, so their performance must be tested regularly. However, in simulated breathing performance testing of breathing masks, the whistling sound produced by the mask must be avoided and suppressed; otherwise, the whistling sound will significantly interfere with the stability and efficiency of the testing. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned technical problems and provide a device and method for eliminating whistling sound in respiratory mask testing. This invention increases the tension at the bottom of the artificial lung by setting an elimination mechanism, thereby increasing the inertia when the transmission mechanism stretches or compresses the artificial lung, changing the resonance point, eliminating resonance, and thus improving the accuracy and efficiency of respiratory mask testing.

[0004] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a whistling noise elimination device for breathing mask testing, comprising a test head mold for conducting airflow, a breathing mask disposed outside the test head mold and connected to a gas cylinder, an artificial lung for simulating human lung breathing disposed below the test head mold, a transmission mechanism for stretching or compressing the artificial lung to cause it to expand or contract, and an elimination mechanism for eliminating the whistling noise generated when the transmission mechanism stretches or compresses the artificial lung. The transmission mechanism is connected to the elimination mechanism, and the test head mold is in communication with the artificial lung. Because the artificial lung is lightweight, the acceleration of the transmission mechanism when stretching or compressing the artificial lung causes resonance between the artificial lung and the breathing mask, resulting in whistling from the breathing mask. This invention, by setting up an elimination mechanism, increases the tension at the bottom of the artificial lung, thereby increasing inertia when the transmission mechanism stretches or compresses the artificial lung, changing the resonance point, eliminating resonance, and thus improving the accuracy and efficiency of breathing mask testing.

[0005] Preferably, the artificial lung is connected to a pressure sensor, which is connected to a programmable logic controller (PLC). The PLC collects pressure data from the pressure sensor to determine whether the artificial lung and / or breathing mask are emitting a whistling sound. It then adjusts the acceleration of the transmission mechanism to change the resonance frequency of the artificial lung and breathing mask, thereby eliminating the whistling sound. The PLC is connected to the transmission mechanism. Based on the pressure data detected by the pressure sensor in the artificial lung, it determines whether a whistling sound has occurred. If a whistling sound is detected, the acceleration of the transmission mechanism is adjusted so that the elimination mechanism connected to the transmission mechanism provides tension, changing the resonance point and eliminating the resonance, thus eliminating the whistling sound.

[0006] Preferably, the system also includes a chassis, on which the test head mold is mounted. The transmission mechanism, elimination mechanism, and artificial lung are all housed within the chassis. A base plate connected to the artificial lung is located below it. The transmission mechanism includes a motor located at the bottom of the chassis, a motor driver connected to the motor, a motor linkage rod connected to the motor, and a motor connecting shaft connected to the motor linkage rod. The motor connecting shaft is connected to the base plate, and the motor driver is connected to a programmable logic controller (PLC). The PLC sends electrical signals to the motor driver, which controls the motor rotation and its acceleration. The motor drives the motor linkage rod to move up and down, which in turn drives the motor connecting shaft to move up and down, thus stretching or compressing the artificial lung.

[0007] Preferably, the elimination mechanism includes a first moving mechanism for stretching or compressing the artificial lung, a first fixing mechanism connected to the first moving mechanism, a first tension rope passing through the first moving mechanism and the first fixing mechanism, and a first spring connected to the first tension rope. The first moving mechanism includes a first movable roller and a first movable connecting rod fixed on the base plate, with the first movable connecting rod connected to the first movable roller. The first fixing mechanism includes a first stationary roller and a first stationary connecting rod located on the upper part of the housing and connected to the first stationary roller, with the first stationary connecting rod connected to the first stationary roller. A first hook is provided on the base plate, and one end of the first tension rope is located on the first hook. The first tension rope passes through the first movable roller and the first stationary roller in sequence and is then connected to the first spring. When the motor connecting shaft moves up and down to stretch or compress the artificial lung, the base plate drives the first moving connecting rod and the first moving roller to move up and down. When the first moving connecting rod and the first moving roller move downward, they stretch the artificial lung, and the first tension rope stretches the first spring, at which point the tension of the first spring is at its maximum. When the first moving connecting rod and the first moving roller gradually move upward, the artificial lung gradually contracts, and the return force of the first spring gradually decreases. When the first moving connecting rod and the first moving roller move to the top, the artificial lung contracts to its minimum, the first spring returns to its initial state, and the tension returns to zero.

[0008] Preferably, the elimination mechanism further includes a second moving mechanism for stretching or compressing the artificial lung, a second fixing mechanism connected to the second moving mechanism, a second tension rope passing through the second moving mechanism and the second fixing mechanism, and a second spring connected to the second tension rope. The second moving mechanism includes a second movable roller and a second movable connecting rod fixed on the base plate, with the second movable connecting rod connected to the second movable roller. The second fixing mechanism includes a second stationary roller and a second stationary connecting rod located on the upper part of the housing and connected to the second stationary roller, with the second stationary connecting rod connected to the second stationary roller. A second hook is provided on the base plate, and one end of the second tension rope is located on the second hook. The second tension rope passes through the second movable roller and the second stationary roller in sequence and is then connected to the second spring. When the motor connecting shaft moves up and down to stretch or compress the artificial lung, the base plate drives the second moving connecting rod and the second moving roller to move up and down. When the second moving connecting rod and the second moving roller move downward, the artificial lung is stretched, and the second tension rope stretches the second spring, at which point the second spring tension is at its maximum. As the second moving connecting rod and the second moving roller gradually move upward, the artificial lung gradually contracts, and the second spring's recoil force gradually decreases. When the second moving connecting rod and the second moving roller move to the top, the artificial lung contracts to its minimum, the second spring returns to its initial state, and the tension returns to zero. By symmetrically arranging the first moving mechanism, the first fixing mechanism, the first tension rope, the first spring, and the second moving mechanism, the second fixing mechanism, the second tension rope, and the second spring on both sides below the artificial lung, the artificial lung is evenly stressed on both sides, effectively reducing the generation of whistling sounds and improving the whistling sound elimination effect.

[0009] Preferably, the test head mold has an opening that communicates with a breathing mask and a circular hole at the bottom that communicates with the opening and is connected to an artificial lung.

[0010] Preferably, the artificial lung includes a bellows that can extend and retract vertically, an air tube is provided between the bellows and the pressure sensor, the bellows is connected to the pressure sensor through the air tube, and a base plate is located below the bellows.

[0011] Preferably, a first fixing block and a second fixing block are fixedly provided inside the chassis, the first fixing block is connected to a first spring, and the second fixing block is connected to a second spring.

[0012] A method for eliminating whistling sounds during a breathing mask test includes the following steps:

[0013] Step 1: Using the whistling noise cancellation device in the breathing mask test, move the artificial lung back and forth, sample the pressure sensor at a fixed frequency, accumulate a certain number of data points, and record them as LP. n The absolute value of the difference between the frequency points before and after the obtained data is taken, and the average value of the absolute values ​​of the difference between the frequency points before and after all the data is taken to obtain the relative threshold PD. The programmable logic controller divides the relative threshold PD into segments according to the statistics and sets them as the howling zone, the stable zone and the possible zone respectively.

[0014] Step 2: The programmable logic controller (PLC) performs real-time judgment on the PD value. If it is determined to be in the howling zone, the PLC adjusts the motor acceleration curve through the motor driver to change the movement speed of the artificial lung. The acceleration time interval from zero to full speed of the motor is adjusted, and the acceleration time for the howling zone is divided into several segments, each with a fixed time. When the howling zone is determined, the fixed time of each segment is increased each time. After increasing to the maximum acceleration time of the howling zone, the fixed time of each segment is decreased. If it is still in the howling zone or stable zone after one cycle, the adjustment is stopped. If it is in the possible zone, fine-tuning is performed, and the original time of each segment is divided equally. The acceleration time is increased or decreased according to the equalized acceleration time, and the cumulative adjustment time does not exceed the original fixed time of each segment.

[0015] Preferably, step one also includes the following: PD > 0.07, judged as the howling zone; PD < 0.05, judged as the stable zone; 0.05 ≤ PD ≤ 0.07, judged as the possible zone.

[0016] The beneficial effects of this invention are:

[0017] 1. This invention can detect the whistling sound generated by the artificial lung and breathing mask through a pressure sensor, and change the movement speed of the artificial lung by controlling the acceleration curve of the motor through a programmable logic controller. The inertia of the artificial lung is increased by the pulling force of the elimination mechanism, thereby changing the resonance point of the artificial lung and breathing mask, eliminating resonance, and thus eliminating the whistling sound. This realizes the function of automatic adjustment to eliminate whistling, and improves the accuracy and efficiency of breathing mask testing.

[0018] 2. The present invention has a simple and easy-to-understand structure, low cost, and is easy to operate, maintain and improve. At the same time, the test results are highly accurate, the operation is simple, the installation is convenient, and the positioning is accurate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the internal structure of the chassis of the present invention.

[0021] Figure 3 This is a schematic diagram of the experimental head mold.

[0022] Figure 4 This is a schematic diagram illustrating the principle of eliminating whistling noise when the bellows is under tension.

[0023] Figure 5 This is a schematic diagram illustrating the principle of eliminating whistling noise in the intermediate state of a bellows.

[0024] Figure 6 This is a diagram illustrating the principle of eliminating whistling noise when the bellows is in a contracted state.

[0025] In the diagram: 1. Test head mold; 11. Mouth; 12. Circular hole; 2. Artificial lung; 21. Bellows; 22. Base plate; 3. Transmission mechanism; 31. Motor; 32. Motor driver; 33. Motor linkage rod; 34. Motor connecting shaft; 4. Elimination mechanism; 41. First moving mechanism; 411. First moving roller; 412. First moving connecting rod; 42. First fixing mechanism; 421. First stationary roller; 422. First stationary connecting rod; 431. First tension. 432. Rope, 433. First spring, 434. First fixing block, 435. First hook, 44. Second moving mechanism, 446. Second moving roller, 447. Second moving connecting rod, 45. Second fixing mechanism, 451. Second stationary roller, 452. Second stationary connecting rod, 461. Second tension rope, 462. Second spring, 463. Second fixing block, 464. Second hook, 5. Pressure sensor, 6. Programmable logic controller, 7. Air pipe, 8. Chassis. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] like Figure 1-3 As shown, the present invention discloses a whistling noise elimination device for a breathing mask test, comprising a test head mold 1 for conducting airflow, a breathing mask (not shown) disposed outside the test head mold 1 and connected to a gas cylinder, an artificial lung 2 for simulating human lung breathing disposed below the test head mold 1, a transmission mechanism 3 for stretching or compressing the artificial lung 2 to cause the artificial lung 2 to expand or contract disposed below the artificial lung 2, and an elimination mechanism 4 for eliminating the whistling noise generated when the transmission mechanism 3 stretches or compresses the artificial lung 2, the transmission mechanism 3 being connected to the elimination mechanism 4, and the test head mold 1 being connected to the artificial lung 2.

[0028] The artificial lung 2 is connected to a pressure sensor 5, and the pressure sensor 5 is connected to a programmable logic controller 6. The programmable logic controller 6 is used to collect pressure data sent by the pressure sensor 5 to determine whether the artificial lung 2 and / or the breathing mask are emitting a whistling sound. By adjusting the acceleration of the transmission mechanism 3, the elimination mechanism 4 changes the resonance frequency of the artificial lung 2 and the breathing mask, thereby eliminating the whistling sound. The programmable logic controller 6 is connected to the transmission mechanism 3.

[0029] It also includes a chassis 8, with the test head mold 1 mounted on the chassis 8. The transmission mechanism 3, the elimination mechanism 4, and the artificial lung 2 are all located inside the chassis 8. A base plate 22 connected to the artificial lung 2 is located below the artificial lung 2. The transmission mechanism 3 includes a motor 31 mounted on the bottom of the chassis 8, a motor driver 32 connected to the motor 31, a motor linkage rod 33 connected to the motor 31, and a motor connecting shaft 34 connected to the motor linkage rod 33. The motor connecting shaft 34 is connected to the base plate 22, and the motor driver 32 is connected to the programmable logic controller 6.

[0030] The elimination mechanism 4 includes a first moving mechanism 41 for stretching or compressing the artificial lung 2, a first fixing mechanism 42 connected to the first moving mechanism 41, a first tension rope 431 passing through the first moving mechanism 41 and the first fixing mechanism 42, and a first spring 432 connected to the first tension rope 431. The first moving mechanism 41 includes a first moving roller 411 and a first moving connecting rod 412 fixed on the base plate 22. The first moving connecting rod 412 is connected to the first moving roller 411. The first fixing mechanism 42 includes a first stationary roller 421 and a first stationary connecting rod 422 located on the upper part of the housing 8 and connected to the first stationary roller 421. The first stationary connecting rod 422 is connected to the first stationary roller 421. A first hook 434 is provided on the base plate 22. One end of the first tension rope 431 is located on the first hook 434. The first tension rope 431 passes through the first moving roller 411 and the first stationary roller 421 in sequence and is then connected to the first spring 432.

[0031] The elimination mechanism 4 also includes a second moving mechanism 44 for stretching or compressing the artificial lung 2, a second fixing mechanism 45 connected to the second moving mechanism 44, a second tension rope 461 passing through the second moving mechanism 44 and the second fixing mechanism 45, and a second spring 462 connected to the second tension rope 461. The second moving mechanism 44 includes a second moving roller 441 and a second moving connecting rod 442 fixed on the base plate 22. The second moving connecting rod 442 is connected to the second moving roller 441. The second fixing mechanism 45 includes a second stationary roller 451 and a second stationary connecting rod 452 located on the upper part of the housing 8 and connected to the second stationary roller 451. The second stationary connecting rod 452 is connected to the second stationary roller 451. A second hook 464 is provided on the base plate 22. One end of the second tension rope 461 is located on the second hook 464. The second tension rope 461 passes through the second moving roller 441 and the second stationary roller 451 in sequence and is then connected to the second spring 462.

[0032] The chassis 8 is fixedly provided with a first fixing block 433 and a second fixing block 463. The first fixing block 433 is connected to the first spring 432, and the second fixing block 463 is connected to the second spring 462.

[0033] The experimental head model 1 has an opening 11 that communicates with a breathing mask and a circular hole 12 that communicates with the opening 11 at the bottom. The circular hole 12 communicates with the artificial lung 2.

[0034] The artificial lung 2 includes a bellows 21 that can extend and retract vertically. A trachea 7 is provided between the bellows 21 and the pressure sensor 5. The bellows 21 is connected to the pressure sensor 5 through the trachea 7.

[0035] In this embodiment, Figure 1 and Figure 2 This is a diagram showing the state of the bellows 21 when it is stretched. Figure 1 and Figure 2The main schematic diagram shows the structure and connection relationships, and the specific schematic diagram is as follows: Figures 4 to 6 As shown.

[0036] like Figure 4 As shown in the figure, only one side of the elimination mechanism 4 is shown in the schematic diagram; the schematic diagrams on both sides are symmetrical. When the motor connecting shaft 34 moves downward to stretch the artificial lung 2, the base plate 22 drives the first moving connecting rod 412 and the first moving roller 411 to move downward, which in turn stretches the artificial lung 2. The first tension rope 431 stretches the first spring 432, at which point the tension of the first spring 432 is at its maximum.

[0037] like Figure 5 As shown, the first moving connecting rod 412 and the first moving roller 411 gradually move upward, and as the artificial lung 2 gradually contracts, the retraction force of the first spring 432 gradually decreases.

[0038] like Figure 6 As shown, the first moving connecting rod 412 and the first moving roller 411 move to the top, the artificial lung 2 contracts to its minimum, the first spring 432 returns to its initial state, and the tension returns to zero.

[0039] A method for eliminating whistling sounds during a breathing mask test includes the following steps:

[0040] Step 1: Using the whistling noise cancellation device in the breathing mask test, the artificial lung 2 is moved back and forth, and the pressure sensor 5 is sampled at a frequency of 1ms. The data is processed by the programmable logic controller 6, and 300ms of data are accumulated to obtain 300 data points, which are denoted as LP1, LP2...LP. n LP n+1 LP 300 The absolute value of the difference between the frequency points before and after the obtained data is taken, resulting in 299 points, denoted as ΔC. n = |LP n+1 -LP n The relative threshold PD is obtained by averaging the absolute values ​​of the differences between the preceding and following frequency points of all data, where PD = PS / 299 and PS = ΔC. 1+……+ △C 299 The programmable logic controller 6 divides the relative threshold PD into segments based on statistics, and sets them as the howling zone, stable zone and possible zone respectively. When PD > 0.07, it is judged as the howling zone; when PD < 0.05, it is judged as the stable zone; when 0.05 ≤ PD ≤ 0.07, it is judged as the possible zone.

[0041] Step 2: The programmable logic controller 6 performs real-time judgment on the PD value. If it is judged to be in the howling zone, the programmable logic controller 6 adjusts the acceleration curve of the motor 31 through the motor driver 32 to change the movement speed of the artificial lung 2. The acceleration time interval of the motor 31 from zero to full speed is adjusted. The acceleration time for the howling zone is divided into 5 segments from 100ms to 500ms. When it is judged to be in the howling zone, it increases by 100ms each time. If it increases to 500ms, it starts to decrease by 100ms each time. If it is in the howling zone or stable zone after one cycle, the adjustment stops. If it is in the possible zone, it is fine-tuned, changing by 20ms each time, with a cumulative adjustment not exceeding 100ms.

[0042] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0043] It should be noted that when a component is referred to as "fixed on" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0044] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

Claims

1. A device for eliminating whistling noise during a breathing mask test, characterized in that: The test head mold (1) is used to conduct airflow, and a breathing mask is provided on the outside of the test head mold (1). An artificial lung (2) for simulating human lung breathing is provided below the test head mold (1). A transmission mechanism (3) is provided below the artificial lung (2) to stretch or compress the artificial lung (2) so that the artificial lung (2) expands or contracts. An elimination mechanism (4) is provided to eliminate the whistling sound generated when the transmission mechanism (3) stretches or compresses the artificial lung (2). The transmission mechanism (3) is connected to the elimination mechanism (4). The test head mold (1) is connected to the artificial lung (2). The artificial lung (2) is provided with a base plate (22) connected to the artificial lung (2). The elimination mechanism includes a moving mechanism connected to the base plate (22), a fixing mechanism fixed relative to the housing (8), a tension rope passing through the moving mechanism and the fixing mechanism, and a spring connected to the tension rope. The moving mechanism moves with the base plate and applies tension to the base plate through the tension rope and the spring. The tension of the elimination mechanism on the artificial lung increases the inertia, thereby changing the resonance point of the artificial lung and the breathing mask and eliminating the resonance.

2. The whistling noise cancellation device for respiratory mask testing according to claim 1, characterized in that: The artificial lung (2) is connected to a pressure sensor (5), and the pressure sensor (5) is connected to a programmable logic controller (6). The programmable logic controller (6) is used to collect pressure data sent by the pressure sensor (5) to determine whether the artificial lung (2) and / or the breathing mask emit a whistling sound, and to eliminate the whistling sound by adjusting the acceleration of the transmission mechanism (3) so that the elimination mechanism (4) changes the resonance frequency of the artificial lung (2) and the breathing mask. The programmable logic controller (6) is connected to the transmission mechanism (3).

3. The whistling noise cancellation device for respiratory mask testing according to claim 2, characterized in that: It also includes a chassis (8), a test head mold (1) is set on the chassis (8), a transmission mechanism (3), an elimination mechanism (4), and an artificial lung (2) are all set inside the chassis (8). The transmission mechanism (3) includes a motor (31) set on the bottom of the chassis (8), a motor driver (32) connected to the motor (31), a motor linkage rod (33) connected to the motor (31), and a motor connecting shaft (34) connected to the motor linkage rod (33). The motor connecting shaft (34) is connected to the base plate (22), and the motor driver (32) is connected to the programmable logic controller (6).

4. The whistling noise cancellation device for respiratory mask testing according to claim 3, characterized in that: The elimination mechanism (4) includes a first moving mechanism (41) for stretching or compressing the artificial lung (2), a first fixing mechanism (42) connected to the first moving mechanism (41), a first tension rope (431) passing through the first moving mechanism (41) and the first fixing mechanism (42), and a first spring (432) connected to the first tension rope (431). The first moving mechanism (41) includes a first movable roller (411) and a first movable connecting rod (412) fixed on the base plate (22). The first movable connecting rod (412) and the first movable roller (411) are connected to the first movable roller (411). 11) Connection; The first fixing mechanism (42) includes a first stationary roller (421) and a first stationary connecting rod (422) located on the upper part of the chassis (8) and connected to the first stationary roller (421). The first stationary connecting rod (422) is connected to the first stationary roller (421). A first hook (434) is provided on the bottom plate (22). One end of the first tension rope (431) is located on the first hook (434). The first tension rope (431) passes through the first moving roller (411) and the first stationary roller (421) in sequence and is connected to the first spring (432).

5. The whistling noise cancellation device for respiratory mask testing according to claim 4, characterized in that: The elimination mechanism (4) also includes a second moving mechanism (44) for stretching or compressing the artificial lung (2), a second fixing mechanism (45) connected to the second moving mechanism (44), a second tension rope (461) passing through the second moving mechanism (44) and the second fixing mechanism (45), and a second spring (462) connected to the second tension rope (461). The second moving mechanism (44) includes a second movable roller (441) and a second movable connecting rod (442) fixed on the base plate (22). The second movable connecting rod (442) is connected to the second movable roller. The roller (441) is connected; the second fixing mechanism (45) includes a second stationary roller (451) and a second stationary connecting rod (452) located on the upper part of the chassis (8) and connected to the second stationary roller (451). The second stationary connecting rod (452) is connected to the second stationary roller (451). A second hook (464) is provided on the base plate (22). One end of the second tension rope (461) is located on the second hook (464). The tension rope passes through the second moving roller (441) and the second stationary roller (451) in sequence and is connected to the second spring (462).

6. The whistling noise cancellation device for respiratory mask testing according to claim 5, characterized in that: The chassis (8) is fixedly provided with a first fixing block (433) and a second fixing block (463). The first fixing block (433) is connected to the first spring (432), and the second fixing block (463) is connected to the second spring (462).

7. The whistling noise cancellation device for respiratory mask testing according to claim 2, characterized in that: The experimental head model (1) has an opening (11) that communicates with the breathing mask and a round hole (12) that communicates with the opening (11) at the bottom. The round hole (12) communicates with the artificial lung (2).

8. The whistling noise cancellation device for respiratory mask testing according to claim 7, characterized in that: The artificial lung (2) includes a bellows (21) that can extend and retract vertically. A trachea (7) is provided between the bellows (21) and the pressure sensor (5). The bellows (21) is connected to the pressure sensor (5) through the trachea (7).

9. A method for eliminating whistling noise during a breathing mask test, characterized in that: Includes the following steps: Step 1: Using the whistling noise cancellation device as described in any of claims 2 to 8 during the breathing mask test, move the artificial lung (2) back and forth, sample the pressure sensor (5) at a fixed frequency, accumulate a certain amount of data, and record it as LP. n The absolute value of the difference between the frequency points before and after the obtained data is taken, and the average value of the absolute values ​​of the difference between the frequency points before and after all the data is taken to obtain the relative threshold PD. The programmable logic controller (6) divides the relative threshold PD into segments according to statistics and sets them as the howling zone, the stable zone and the possible zone respectively. Step 2: The programmable logic controller (6) makes a real-time judgment on the PD value. If it is judged to be in the howling zone, the programmable logic controller (6) adjusts the acceleration curve of the motor (31) through the motor driver (32) to change the movement speed of the artificial lung (2). The acceleration time interval of the motor (31) from zero to full speed is adjusted. The acceleration time for the howling zone is divided into several segments, and each segment is set with a fixed time. When it is judged to be in the howling zone, the fixed time set for each segment is increased each time. After the maximum acceleration time of the howling zone is reached, the fixed time of each segment is decreased. If it is still in the howling zone or stable zone after one cycle, the adjustment is stopped. If it is in the possible zone, fine adjustment is made. The original time of each segment is divided equally again, and the acceleration time after the division is increased or decreased. The cumulative adjustment time does not exceed the original fixed time of each segment.

10. The method for eliminating whistling noise during a breathing mask test according to claim 9, characterized in that: Step one also includes the following: PD > 0.07, judged as the howling zone; PD < 0.05, judged as the stable zone; 0.05 ≤ PD ≤ 0.07, judged as the possible zone.

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