A ventilation device for generating a rectangular wave pulse air flow and an operation method thereof

Abstract

The present invention discloses a ventilation device for generating a rectangular wave pulse air flow. The device includes an air source, three pulse air flow pipelines, a solenoid valve, and a rectangular wave pulse power supply; the solenoid valve includes an inlet and three outlets, the air source is communicated with the inlet, the first outlet is communicated with the first pulse air flow pipeline, the second outlet is communicated with the second pulse air flow pipeline, and the third outlet is communicated with the third pulse air flow pipeline; a valve rod is provided in the solenoid valve, and the rectangular wave pulse power supply is used to control the valve rod to realize the communication between the air source and the first pulse air flow pipeline, or the communication between the air source and the second pulse air flow pipeline, or the communication between the air source and the third pulse air flow pipeline. The ventilation device of the present invention can generate a rectangular wave pulse air flow, and has the advantages of simple device structure, small equipment investment, easy adjustment, etc., and can effectively regulate parameters such as the frequency, amplitude, and duty cycle of the rectangular wave pulse air flow.

Description

Technical Field

[0001] The present invention relates to a ventilation device for generating a rectangular wave pulse air flow and an operation method thereof. Background Art

[0002] Ventilation technology is widely used in fluidization in the chemical industry, such as in processes like silo discharging, aeration tanks, etc., as well as in fluidized beds, and ventilators in the medical field.

[0003] Gas-solid fluidized beds are common reactor forms in the chemical industry. When the gas flow velocity is different, the bed layer can have different fluidization characteristics. Appropriate ventilation technology can make the mass transfer contact between the gas and solid phases more sufficient, and the reactor efficiency higher. Moreover, pulsed ventilation has better heat and mass transfer effects, can improve the quality of particle fluidization, and is widely used in fields such as fluidized bed drying.

[0004] Powder flow is the basis of powder engineering. It is the link connecting the material properties of single particles with unit operations in powder technology, such as powder storage, feeding, conveying, mixing, etc. Ventilation technology can significantly enhance powder fluidity and is an important and popular method for strengthening powder flow and reducing arching and clogging in silos.

[0005] In the process of sewage treatment, it is usually necessary to use a ventilation pipe to introduce gas into the aeration tank to degrade the organic pollutants in the sewage. One end of the ventilation pipe is connected to a ventilation device, and the other end extends into the bottom of the aeration tank. The gas in the ventilation device reaches the bottom of the aeration tank along the ventilation pipe and comes into full contact with the sewage in the aeration tank, causing the degradation of the organic pollutants in the sewage. The performance of the ventilation device directly affects the degree of degradation of the organic pollutants.

[0006] High-frequency oscillatory ventilation is often used in the medical field. Through a diaphragm piston, the gas after mixing of air and oxygen generates oscillation, and ventilation is carried out at a breathing frequency less than the physiological tidal volume and more than 4 times the normal breathing frequency. Both inhalation and exhalation are active. During high-frequency ventilation, the gas exchange is different from that of conventional ventilation. Due to the high-frequency oscillation of the gas, the convective stirring effect, convective diffusion, etc. enhance the gas molecule diffusion effect.

[0007] The core component of the existing gas pulse generator is the electromagnetic pulse valve, which often adopts a "one-in-one-out" structure. By sending an electrical signal through a pulse injection controller, the "opening" and "closing" of the valve are realized. This kind of electromagnetic pulse valve is widely used in fields such as bag dust removal and ejection systems. By converting the electrical pulse into a mechanical pulsation, the powerful energy of the pulsating gas becomes momentum, and a huge impact force can be released in a short time. However, during the switching process of the valve stem, the closing of the valve will cause the upstream air flow to temporarily accumulate in the pipeline and the valve air chamber, resulting in an instantaneous high pressure. This pressure will be released when the valve opens next time. This causes the instantaneous ventilation volume generated by the downstream air flow to be much higher than the set value, posing a challenge to the process that requires precise control of the gas flow. To solve the above problems, existing methods mostly set a buffer tank at the front end of the pulse valve. However, due to the delay in the opening and closing process of the solenoid valve and the damping effect of the pipeline, the actually generated pulse air flow is approximately a sine wave, rather than a rectangular wave, and the waveform parameters of the pulse air flow cannot be accurately regulated. In addition, existing ventilation devices are difficult to generate rectangular wave pulse air flows with different duty cycles at the same time. Summary of the Invention

[0008] The present invention provides a ventilation device for generating a rectangular wave pulse air flow and an operation method thereof to solve the problem in the prior art that it is difficult to obtain a rectangular wave pulse air flow, or the waveform parameters of the generated rectangular wave pulse air flow are not flexible to adjust. The ventilation device of the present invention can generate a rectangular wave pulse air flow, and has the advantages of simple device structure, small equipment investment, easy adjustment, etc., and can effectively regulate parameters such as the frequency, amplitude, and duty cycle of the rectangular wave pulse air flow.

[0009] The present invention solves the above technical problems through the following technical solutions.

[0010] The present invention provides a ventilation device for generating a rectangular wave pulse air flow, which includes a gas source, three pulse air flow pipelines, a solenoid valve, and a rectangular wave pulse power supply;

[0011] The solenoid valve includes an inlet and three outlets. The gas source is connected to the inlet, the first outlet is connected to the first pulse air flow pipeline, the second outlet is connected to the second pulse air flow pipeline, and the third outlet is connected to the third pulse air flow pipeline;

[0012] A valve stem is provided in the solenoid valve, and the rectangular wave pulse power supply is used to control the valve stem to realize the connection between the gas source and the first pulse air flow pipeline, or the connection between the gas source and the second pulse air flow pipeline, or the connection between the gas source and the third pulse air flow pipeline.

[0013] In the present invention, the gas source can be conventional in the art, generally compressed gas from an air compressor or a gas cylinder, and the gas of the gas source can be compressed air, nitrogen, carbon dioxide, etc.

[0014] In the present invention, preferably, a first energized coil and a second energized coil are provided inside the solenoid valve. Those skilled in the art will understand after understanding the technical solution of the present invention that the movement state of the valve stem can be controlled by changing the energized and de-energized states of the first energized coil and the second energized coil. The movement state of the valve stem generally includes the position of the valve stem, the residence time, and the movement frequency. (1) When the first energized coil is in the energized state and the second energized coil is in the de-energized state, the valve stem moves to connect the gas source with the first pulsed gas flow pipeline; when the first energized coil is in the de-energized state and the second energized coil is in the energized state, the valve stem moves to connect the gas source with the second pulsed gas flow pipeline; when both the first energized coil and the second energized coil are in the de-energized state, the valve stem moves to connect the gas source with the third pulsed gas flow pipeline; thereby controlling the position movement of the valve stem so that the gas source is connected with different independent pulsed gas flow pipelines. Since the gas can always be discharged through a certain pulsed gas flow pipeline, a sharp increase in pressure upstream of the solenoid valve is effectively avoided. (2) The residence time of the valve stem at each position can be controlled by the duration of the energized and de-energized states of the first energized coil and the second energized coil. (3) The movement frequency of the valve stem can be controlled by the frequency of the energized and de-energized states of the first energized coil and the second energized coil. (4) The pulsed gas flows discharged from different independent pulsed gas flow pipelines can generate rectangular waves with different waveform parameters according to the performance characteristics of the solenoid valve.

[0015] In the present invention, those skilled in the art will understand after understanding the technical solution of the present invention that each outlet of the solenoid valve is respectively connected to a pulsed gas flow pipeline, so the number of outlets of the solenoid valve is equal to the number of pulsed gas flow pipelines.

[0016] Among them, the solenoid valve is preferably a high-frequency solenoid valve.

[0017] In the present invention, the rectangular wave pulse power supply can be conventional in the art, which refers to a pulse power supply whose output waveform is a rectangular wave.

[0018] Among them, preferably, a first gas flow meter is provided between the gas source and the inlet, which is used to control and measure the size of the gas flow in the pulsed gas flow pipeline, and more preferably a gas mass flow meter or a metal float flow meter, etc.

[0019] In the present invention, the ventilation device preferably further includes a stable air flow pipeline, and the air source is respectively connected to the inlet and the stable air flow pipeline; the downstream of the stable air flow pipeline converges with the downstream of the first pulsed air flow pipeline, the second pulsed air flow pipeline or the third pulsed air flow pipeline into a single pipeline, so that the pulsed air flow and the stable air flow can be used jointly, thereby enabling rich adjustment of the amplitude of the pulsed air flow.

[0020] Preferably, the stable air flow pipeline is provided with a valve. Preferably, the valve is a ball valve for controlling the connection state of the stable air flow pipeline.

[0021] Preferably, the stable air flow pipeline is provided with a second gas flow meter for controlling and measuring the magnitude of the gas flow in the stable air flow pipeline, more preferably a gas mass flow meter or a metal float flow meter, etc.

[0022] In a preferred embodiment, the stable air flow pipeline is provided with the valve and the second gas flow meter connected in sequence.

[0023] Among them, preferably, the air source is connected to a gas storage tank, and the gas storage tank serves to store and buffer gas. The gas storage tank includes at least two gas outlets. The first gas outlet is connected to the inlet, and the second gas outlet is connected to the stable air flow pipeline. Preferably, a first gas flow meter is provided between the gas storage tank and the inlet.

[0024] The present invention also provides an operation method of the ventilation device as described above. In the operation method of the ventilation device, it includes the following steps:

[0025] Turn on the ventilation device, set the duty cycle of the rectangular wave pulsed air flow, and ventilation can be achieved.

[0026] Among them, the adjustment method of the duty cycle of the rectangular wave pulsed air flow is to adjust the on-off interval time of the rectangular wave pulsed power supply and the time when the first pulsed air flow pipeline, the second pulsed air flow pipeline or the third pulsed air flow pipeline is connected, and its rule conforms to:

[0027] D1 = t1 / T, D2 = t2 / T, D3 = t3 / T, T = t1 + t2 + t3;

[0028] D1, D2, and D3 are respectively the duty cycles of the rectangular wave pulsed air flow in the first pulsed air flow pipeline, the second pulsed air flow pipeline, and the third pulsed air flow pipeline. T is the time of a single cycle, t1 is the time when the first pulsed air flow pipeline is connected within a single cycle, that is, the time when the position of the valve stem maintains the opening of the first outlet; t2 is the time when the second pulsed air flow pipeline is connected within a single cycle; t3 is the time when the third pulsed air flow pipeline is connected within a single cycle.

[0029] In the present invention, preferably, the operation method of the ventilation device further includes setting the frequency of the rectangular wave pulse air flow, and the adjustment method of the frequency of the rectangular wave pulse air flow is to adjust the pulse frequency of the rectangular wave pulse power supply.

[0030] Those skilled in the art know that the valve stems of different solenoid valves have different maximum operating frequencies. When the pulse frequency of the rectangular wave pulse power supply is not higher than the maximum operating frequency of the valve stem, the frequency of the rectangular wave pulse air flow is equal to the frequency of the rectangular wave pulse power supply and equal to the operating frequency of the valve stem; when the pulse frequency of the rectangular wave pulse power supply is higher than the maximum operating frequency of the valve stem, the frequency of the rectangular wave pulse air flow is equal to the maximum operating frequency of the valve stem. Wherein, the operating frequency f of the valve stem = 1 / T.

[0031] In the present invention, preferably, the operation method of the ventilation device further includes setting the amplitude of the rectangular wave pulse air flow, and the adjustment method of the amplitude of the rectangular wave pulse air flow (the amplitude refers to the maximum value of the wave function of the rectangular wave pulse air flow deviating from the equilibrium position) is as follows:

[0032] When only the pulse air flow pipeline is connected, so that the average gas flow rate q1 of the pulse air flow pipeline is 0 - 160 L / min (when a first gas flow meter is provided between the gas source and the inlet, it can be adjusted by adjusting the first gas flow meter); by adjusting the operating frequency f of the valve stem to be 0 - 200 Hz, the numerical relationship between the instantaneous gas flow rate q of the rectangular wave pulse air flow and q1 and f is q = q1 / 2 + q1sgn[sin(2πft)] / 2; wherein, q1 is the average gas flow rate of the pulse air flow pipeline, f is the operating frequency of the valve stem, and t is time. According to the above function, the wave function of the pulse air flow generated by the pulse air flow pipeline oscillates within the range of 0 - q1, and the amplitude is q1 / 2;

[0033] When the gas source is respectively connected to the inlet and the stable air flow pipeline, and the downstream of the stable air flow pipeline converges with the downstream of the first pulsed air flow pipeline, the second pulsed air flow pipeline or the third pulsed air flow pipeline into one path, the average gas flow rate q1 of the pulsed air flow pipeline is 0 - 160 L / min (when a first gas flow meter is provided between the gas source and the inlet, the first gas flow meter can be adjusted); by adjusting the action frequency f of the valve stem to be 0 - 200 Hz; the gas flow rate q2 of the stable air flow pipeline is 0 - 160 L / min (when a second gas flow meter is provided on the stable air flow pipeline, the second gas flow meter can be adjusted); the numerical relationship between the instantaneous gas flow rate q of the rectangular wave pulsed air flow and q1, q2 and f is q = (q1 / 2 + q2) + q1sgn[sin(2πft)] / 2; where, q1 is the average gas flow rate of the pulsed air flow pipeline, q2 is the gas flow rate of the stable air flow pipeline, f is the action frequency of the valve stem, and t is time. According to the above function, the wave function of the generated pulsed air flow oscillates within the range of q2 to q1 + q2, and the amplitude is q1 / 2.

[0034] Those skilled in the art will know after understanding the technical solution of the present invention that the duty cycle, frequency, amplitude, etc. of the rectangular wave pulsed air flow can be adjusted according to subsequent applications.

[0035] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be arbitrarily combined to obtain various preferred embodiments of the present invention.

[0036] The positive and progressive effects of the present invention are as follows:

[0037] The present invention adopts a solenoid valve with three outlets, avoiding the drawback of rectangular wave deformation caused by gas aggregation. The three pulsed air flow pipelines can independently generate rectangular wave pulsed air flows with different duty cycles, and the frequency of the rectangular wave pulsed air flow is equal to the action frequency of the valve stem. Thus, the duty cycle, frequency, and amplitude of the rectangular wave are adjustable. The ventilation device of the present invention has the advantages of simple structure, good regulation effect, multiple functions, high efficiency, stability, etc.

[0038] In a preferred embodiment, by converging the stable air flow pipeline with one of the pulsed air flow pipelines, the adjustment of the amplitude of the rectangular wave is further realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the ventilation device for generating rectangular wave pulsed air flow in Embodiment 1.

[0040] Figure 2 High-frequency rectangular wave pulsed air flow in Embodiment 2.

[0041] Figure 3The rectangular wave pulse air flow after duty cycle adjustment in Example 3.

[0042] Figure 4 The rectangular wave pulse air flow after jointly adjusting the amplitude of the pulse air flow and the stable air flow in Example 4.

[0043] Description of the reference numerals

[0044] Gas source 1

[0045] First pulse air flow pipeline 2

[0046] Second pulse air flow pipeline 3

[0047] Third pulse air flow pipeline 4

[0048] Solenoid valve 5

[0049] Rectangular wave pulse power supply 6

[0050] Inlet 7

[0051] First outlet 8

[0052] Second outlet 9

[0053] Third outlet 10

[0054] Valve stem 11

[0055] First gas flowmeter 12

[0056] Stable air flow pipeline 13

[0057] Ball valve 14

[0058] Second gas flowmeter 15

[0059] Gas storage tank 16 Detailed implementation manners

[0060] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0061] Example 1

[0062] As Figure 1As shown in the figure, Embodiment 1 provides a ventilation device for generating a rectangular wave pulsed air flow, which includes a gas source 1, three pulsed air flow pipelines, a solenoid valve 5 and a rectangular wave pulsed power supply 6; the solenoid valve 5 includes an inlet 7 and three outlets, the gas source 1 is communicated with the inlet 7, the first outlet 8 is communicated with the first pulsed air flow pipeline 2, the second outlet 9 is communicated with the second pulsed air flow pipeline 3, and the third outlet 10 is communicated with the third pulsed air flow pipeline 4; a valve rod 11 is arranged in the solenoid valve 5, and the rectangular wave pulsed power supply 6 is used to control the valve rod 11 to realize the communication between the gas source 1 and the first pulsed air flow pipeline 2, or the communication between the gas source 1 and the second pulsed air flow pipeline 3, or the communication between the gas source 1 and the third pulsed air flow pipeline 4.

[0063] The gas source 1 can be compressed air, nitrogen, carbon dioxide, etc.

[0064] A first energized coil and a second energized coil are arranged in the solenoid valve 5. By changing the energized and de-energized states of the first energized coil and the second energized coil, the action state of the valve rod 11 can be controlled. The action state of the valve rod 11 generally includes the position of the valve rod 11, the residence time, and the action frequency. (1) When the first energized coil is in the energized state and the second energized coil is in the de-energized state, the valve rod 11 moves to make the gas source 1 communicate with the first pulsed air flow pipeline 2; when the first energized coil is in the de-energized state and the second energized coil is in the energized state, the valve rod 11 moves to make the gas source 1 communicate with the second pulsed air flow pipeline 3; when both the first energized coil and the second energized coil are in the de-energized state, the valve rod 11 moves to make the gas source 1 communicate with the third pulsed air flow pipeline 4; thus, the position movement of the valve rod 11 is controlled to make the gas source 1 communicate with different independent pulsed air flow pipelines. Since the gas can always be discharged through a certain pulsed air flow pipeline, the pressure surge upstream of the solenoid valve 5 is effectively avoided. (2) The duration of the energized and de-energized states of the first energized coil and the second energized coil can control the residence time of the valve rod 11 at each position. (3) The frequency of the energized and de-energized states of the first energized coil and the second energized coil can control the action frequency of the valve rod 11. (4) According to the performance characteristics of the solenoid valve 5, the pulsed air flows discharged from different independent pulsed air flow pipelines can generate rectangular waves with different waveform parameters.

[0065] The solenoid valve 5 is a high-frequency solenoid valve.

[0066] The rectangular wave pulsed power supply 6 refers to a pulsed power supply whose output waveform is a rectangular wave.

[0067] The ventilation device further includes a stable air flow pipeline 13, the gas source 1 is respectively connected with the inlet 7 and the stable air flow pipeline 13; the downstream of the stable air flow pipeline 13 converges with the downstream of the first pulsed air flow pipeline 2, the second pulsed air flow pipeline 3 or the third pulsed air flow pipeline 4 into a pipeline, so that the pulsed air flow and the stable air flow can be used jointly, thereby being able to richly adjust the amplitude of the pulsed air flow.

[0068] The stable air flow pipeline 13 is provided with a ball valve 14 for controlling the connection state of the stable air flow pipeline 13.

[0069] The stable air flow pipeline 13 is provided with a second gas flowmeter 15 for controlling and measuring the gas flow rate of the stable air flow pipeline 13, which is a gas mass flowmeter.

[0070] The stable air flow pipeline 13 is provided with a ball valve 14 and a second gas flowmeter 15 connected in sequence.

[0071] The gas source 1 is connected to the gas storage tank 16. The gas storage tank 16 serves to store and buffer the gas. The gas storage tank 16 includes at least two gas outlets. The first gas outlet is connected to the inlet 7, and the second gas outlet is connected to the stable air flow pipeline 13. A first gas flowmeter 12 is provided between the gas storage tank 16 and the inlet 7 for controlling and measuring the gas flow rate of the pulse air flow pipeline, which is a gas mass flowmeter.

[0072] Embodiment 2

[0073] The ventilation device in Embodiment 1 is adopted, and after the downstream of the stable air flow pipeline 13 converges with the downstream of the first pulse air flow pipeline 2, the second pulse air flow pipeline 3 or the third pulse air flow pipeline 4 into a pipeline, it is further connected to a pressure sensor and a data acquisition system. The pressure sensor is used to calibrate the pressure signal of the rectangular wave pulse air flow generated by the ventilation device.

[0074] In this embodiment, only the first pulse air flow pipeline 2 is used to generate the rectangular wave pulse air flow, and q1 = 20 L / min. By adjusting the on / off time of the pulse power supply, a rectangular wave, that is, a square wave, with a frequency f = 50 Hz, an amplitude A = q1 / 2 = 10 L / min, and a duty cycle D = 1 / 2 is obtained. The pressure signal of the pulse air flow is measured by the pressure sensor, as Figure 2 shown, the generated waveform is basically a rectangular wave, rather than a sine wave similar to that generated by a traditional pulse valve.

[0075] Embodiment 3

[0076] The ventilation device in Embodiment 1 is adopted, and after the downstream of the stable air flow pipeline 13 converges with the downstream of the first pulse air flow pipeline 2, the second pulse air flow pipeline 3 or the third pulse air flow pipeline 4 into a pipeline, it is further connected to a pressure sensor and a data acquisition system. The pressure sensor is used to calibrate the pressure signal of the rectangular wave pulse air flow generated by the ventilation device.

[0077] In this embodiment, only the first pulsed gas flow pipeline 2 is used to generate a rectangular wave pulsed gas flow, and q1 = 20 L / min. By adjusting the on / off time of the pulsed power supply, a rectangular wave with a frequency f = 10 Hz, an amplitude A = q1 / 2 = 10 L / min, and a duty cycle D = 1 / 8 is obtained. The pressure signal of the pulsed gas flow is measured by a pressure sensor, as Figure 3 shown, the generated waveform is basically a rectangular wave, rather than a sine wave generated by a traditional pulsed valve.

[0078] Embodiment 4

[0079] The ventilation device as in Embodiment 1 is adopted, and after converging into a pipeline at the downstream of the stable gas flow pipeline 13 and the downstream of the first pulsed gas flow pipeline 2, the second pulsed gas flow pipeline 3 or the third pulsed gas flow pipeline 4, it is further connected to 1 pressure sensor and a data acquisition system. The pressure sensor is used to calibrate the pressure signal of the rectangular wave pulsed gas flow generated by the ventilation device.

[0080] In this embodiment, the second pulsed gas flow pipeline 3 and the stable gas flow pipeline 13 are opened simultaneously. For the second pulsed gas flow pipeline 3, q1 = 20 L / min, and for the stable gas flow pipeline 13, q2 = 5 L / min. Among them, the second pulsed gas flow pipeline 3 is used to adjust the frequency and duty cycle of the wave function, and the stable gas flow pipeline 13 is used to adjust the flow rate range of the wave function. As Figure 4 shown, the generated rectangular wave has a frequency f = 10 Hz, an amplitude A = q1 / 2 = 10 L / min, and a duty cycle D = 1 / 2.

Claims

1. A ventilation device for generating a rectangular wave pulse air flow, characterized in that, It includes a gas source, three pulsed gas flow pipelines, a solenoid valve, and a rectangular wave pulsed power supply; The solenoid valve includes an inlet and three outlets. The gas source is connected to the inlet. The first outlet is connected to the first pulsed gas flow pipeline, the second outlet is connected to the second pulsed gas flow pipeline, and the third outlet is connected to the third pulsed gas flow pipeline; A valve stem is provided inside the solenoid valve. The rectangular wave pulsed power supply is used to control the valve stem to realize the connection between the gas source and the first pulsed gas flow pipeline, or the connection between the gas source and the second pulsed gas flow pipeline, or the connection between the gas source and the third pulsed gas flow pipeline; The ventilation device further includes a stable gas flow pipeline. The gas source is respectively connected to the inlet and the stable gas flow pipeline; The downstream of the stable gas flow pipeline converges with the downstream of the first pulsed gas flow pipeline, the second pulsed gas flow pipeline, or the third pulsed gas flow pipeline into one pipeline; A first energized coil and a second energized coil are provided inside the solenoid valve; The solenoid valve is a high-frequency solenoid valve.

2. The ventilation device for generating a rectangular wave pulse air flow according to claim 1, characterized in that, The gas of the gas source is compressed air, nitrogen, or carbon dioxide.

3. The ventilation device for generating a rectangular wave pulse air flow according to claim 1, characterized in that, A first gas flowmeter is provided between the gas source and the inlet.

4. The ventilation device for generating a rectangular wave pulse air flow according to claim 3, characterized in that, The first gas flowmeter is a gas mass flowmeter or a metal float flowmeter.

5. The ventilation device for generating a rectangular wave pulse air flow according to claim 1, characterized in that, A valve is provided on the stable gas flow pipeline; A second gas flowmeter is provided on the stable gas flow pipeline.

6. The ventilation device for generating a rectangular wave pulse air flow according to claim 5, characterized in that, The valve is a ball valve.

7. The ventilation device for generating a rectangular wave pulse air flow according to claim 5, characterized in that, The second gas flowmeter is a gas mass flowmeter or a metal float flowmeter.

8. The ventilation device for generating a rectangular wave pulse air flow according to claim 5, wherein The stable gas flow pipeline is provided with the valve and the second gas flowmeter connected in sequence.

9. The ventilation device for generating a rectangular wave pulse air flow according to claim 1, wherein, The gas source is connected to a gas storage tank. The gas storage tank plays a role in storing and buffering gas. The gas storage tank includes at least 2 gas outlets. The first gas outlet is connected to the inlet, and the second gas outlet is connected to the stable gas flow pipeline.

10. The ventilation device for generating a rectangular wave pulse air flow according to claim 9, characterized in that, A first gas flowmeter is provided between the gas storage tank and the inlet.

11. A method for operating a ventilation device that generates a rectangular wave pulse air flow as described in any one of claims 1 to 10, characterized in that, In the operation method of the ventilation device, it includes the following steps: Turn on the ventilation device, set the duty cycle of the rectangular wave pulsed gas flow, and ventilation can be achieved; Among them, the adjustment method of the duty cycle of the rectangular wave pulsed gas flow is to adjust the on-off interval time of the rectangular wave pulsed power supply and adjust the connection time of the first pulsed gas flow pipeline, the second pulsed gas flow pipeline, or the third pulsed gas flow pipeline. Its rules are as follows: D1 = t1 / T, D2 = t2 / T, D3 = t3 / T, T = t1 + t2 + t3; D1, D2, and D3 are respectively the duty cycles of the rectangular wave pulsed gas flow in the first pulsed gas flow pipeline, the second pulsed gas flow pipeline, and the third pulsed gas flow pipeline. T is the time of a single cycle. t1 is the connection time of the first pulsed gas flow pipeline within a single cycle, t2 is the connection time of the second pulsed gas flow pipeline within a single cycle, and t3 is the connection time of the third pulsed gas flow pipeline within a single cycle.

12. The operating method of the ventilation device for generating a rectangular wave pulse air flow according to claim 11, characterized in that The operation method of the ventilation device further includes setting the frequency of the rectangular wave pulsed gas flow. The adjustment method of the frequency of the rectangular wave pulsed gas flow is to adjust the pulse frequency of the rectangular wave pulsed power supply.

13. The operating method of the ventilation device for generating a rectangular wave pulse air flow according to claim 11, characterized in that, The operation method of the ventilation device further includes setting the amplitude of the rectangular wave pulse air flow, and the amplitude adjustment method of the rectangular wave pulse air flow is as follows: When only the pulse air flow pipeline is connected, so that the average gas flow rate q1 of the pulse air flow pipeline is 0 to 160 L / min; by adjusting the action frequency f of the valve stem to be 0 to 200 Hz, the relationship between the instantaneous gas flow rate q of the rectangular wave pulse air flow and the values of q1 and f is q = q1 / 2 + q1sgn[sin(2πft)] / 2; where, q1 is the average gas flow rate of the pulse air flow pipeline, f is the action frequency of the valve stem, and t is time; When the air source is respectively connected to the inlet and the stable air flow pipeline, and the downstream of the stable air flow pipeline converges with the downstream of the first pulse air flow pipeline, the second pulse air flow pipeline or the third pulse air flow pipeline into one path, so that the average gas flow rate q1 of the pulse air flow pipeline is 0 to 160 L / min; by adjusting the action frequency f of the valve stem to be 0 to 200 Hz; making the gas flow rate q2 of the stable air flow pipeline be 0 to 160 L / min; the relationship between the instantaneous gas flow rate q of the rectangular wave pulse air flow and the values of q1, q2 and f is q = (q1 / 2 + q2) + q1sgn[sin(2πft)] / 2; where, q1 is the average gas flow rate of the pulse air flow pipeline, q2 is the gas flow rate of the stable air flow pipeline, f is the action frequency of the valve stem, and t is time.

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