Aerosol mixing chamber and aerosol diluting device

Abstract

The utility model discloses an aerosol mixing chamber and an aerosol diluting device, the aerosol mixing chamber comprises a cuboid shell, both sides of the cuboid shell are respectively provided with a polyfluortetraethylene plate with an opening, the cuboid shell is also internally provided with a tungsten flow guide cover, and the flow guide cover comprises two symmetrical arc-shaped shielding covers, the outer ends of the two arc-shaped shielding covers are respectively arranged above the openings of the two polyfluortetraethylene plates and are connected with the polyfluortetraethylene plates, and the inner ends of the two arc-shaped shielding covers are respectively connected with the two ends of the connecting cover; and the cuboid shell is connected with the negative pole of the high-voltage power supply. One opening of the aerosol mixing chamber is an air inlet, the other opening of the aerosol mixing chamber is an air outlet, and a servo loop is further arranged between the air outlet and the air inlet. According to the utility model, the flow can be adaptively adjusted by adjusting the servo loop according to the sampling flow and the dilution ratio required by the aerosol analyzing and testing equipment, and uniformly mixed aerosol can be generated.

Description

Technical Field

[0001] The utility model relates to an aerosol mixing and dilution technology, and more specifically, to an aerosol mixing chamber and an aerosol dilution device. Background Art

[0002] Aerosol dilution devices are currently widely used in environmental monitoring, aerosol scientific research, aerosol monitoring instruments and equipment calibration, etc. The main principle is to dilute high-concentration aerosols according to a certain dilution ratio after passing through the aerosol dilution device, and then pass the diluted aerosols into relevant instruments and equipment for testing and monitoring of aerosol particle concentration or mass concentration.

[0003] Existing aerosol dilution devices such as Figure 1 As shown, the high-concentration aerosol is divided into two paths, one of which passes through the flow regulating valve 2 and enters the mixing chamber 4, and the other passes through the high-efficiency filter 3 and the flow regulating valve 1 and enters the mixing chamber 4. By adjusting the flow regulating valves 1 and 2, the gas in the two branches passes according to a certain flow ratio, and finally forms an aerosol with a certain dilution ratio in the mixing chamber 4. The diluted aerosol after a certain dilution ratio can be used for subsequent instrument and equipment testing.

[0004] In order to meet the use requirements of monitoring and analysis equipment, the aerosol dilution device of the prior art is often set to a very high dilution ratio, which is generally greater than 100 times, and some application fields require a dilution ratio of more than 1000 times. In order to meet the use of analytical monitoring equipment with different sampling flow requirements, different flow regulating valves are usually set to achieve the required flow ratio, thereby meeting the required dilution ratio requirements.

[0005] However, for those with small sampling flow rates but high dilution ratios, it is very difficult for the current aerosol analysis test equipment to achieve a certain flow ratio to form a certain aerosol dilution ratio by setting a flow regulating valve. This is because the flow regulating valve that can control small flow rates is difficult to produce. Taking the aerosol analysis system sampling volume of 1L / min as an example, in order to achieve a dilution ratio of 500 times or 1000 times, the flow rate of the flow regulating valve 2 needs to be set to a flow point of 0.002L / min or 0.001L / min. However, flow regulating valves with such a small flow rate are currently difficult to manufacture and purchase, so the existing aerosol dilution devices are difficult to meet the requirements.

[0006] also, Figure 1The mixing chamber 4 in the apparatus adopts the form of a hollow cavity without a special mixing structure, which results in poor aerosol mixing effect. Secondly, since aerosol particles themselves or mechanical friction between them during movement will generate a large amount of charge, aerosols with a large amount of charge will migrate and agglomerate to a certain extent under the action of the charge force, thereby changing the particle size and distribution of the original aerosol, and introducing a large measurement error for subsequent aerosol analysis and testing. Utility Model Content

[0007] In view of the defects existing in the prior art, the purpose of the utility model is to provide an aerosol mixing chamber and an aerosol dilution device.

[0008] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0009] According to a first aspect of the present invention, there is provided an aerosol mixing chamber, comprising a rectangular parallelepiped housing,

[0010] Polytetrafluoroethylene plates with openings are respectively provided on both sides of the rectangular shell, and a tungsten air deflector is also provided inside the rectangular shell. The air deflector includes two symmetrical arc-shaped shielding covers and a connecting cover. The outer ends of the two arc-shaped shielding covers are respectively arranged above the openings of the two polytetrafluoroethylene plates and connected to the polytetrafluoroethylene plates, and the inner ends of the two arc-shaped shielding covers are respectively connected to the two ends of the connecting cover;

[0011] The deflector is connected to the positive pole of a high-voltage power supply, and the rectangular shell is connected to the negative pole of the high-voltage power supply. The voltage range of the high-voltage power supply is 3000 to 10000V.

[0012] The arc angle range of the arc-shaped shielding cover is 60° to 90°.

[0013] The distance between the connecting cover and the bottom surface of the rectangular shell is in the range of 3 to 8 mm.

[0014] The high voltage power supply ranges from 6000V to 9000V.

[0015] According to a second aspect of the present invention, there is also provided an aerosol dilution device, comprising the aerosol mixing chamber of the first aspect of the present invention, wherein one opening of the aerosol mixing chamber is an air inlet, and the other opening is an air outlet, the air inlet is connected to a high-concentration aerosol, and a servo loop is further provided between the air outlet and the air inlet, wherein the servo loop comprises a first high-efficiency filter, a servo air pump, an electronic flow regulating valve, and a second high-efficiency filter connected in sequence;

[0016] The air outlet, the servo air pump and the electronic flow regulating valve are all connected to a flow servo controller.

[0017] Compared with the prior art, the aerosol mixing chamber and the aerosol dilution device of the utility model can adaptively adjust the flow rate and generate a uniformly mixed aerosol by adjusting the servo loop according to the sampling flow rate and dilution ratio required by the aerosol analysis and testing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the principle of an aerosol dilution device in the prior art;

[0019] Figure 2 It is a schematic diagram of the principle of an embodiment of the utility model;

[0020] Figure 3 for Figure 1 Schematic diagram of the structure of the aerosol mixing chamber;

[0021] Figure 4 for Figure 1 Schematic diagram of the three-dimensional decomposition of the aerosol mixing chamber. DETAILED DESCRIPTION

[0022] The technical solution of the utility model is further explained below in conjunction with the accompanying drawings and embodiments.

[0023] See also Figure 2 , 3 , an aerosol dilution device as shown in 4, comprising:

[0024] The aerosol mixing chamber 11 includes a rectangular shell 111 made of stainless steel 316. A polytetrafluoroethylene plate 112 with openings is provided on both sides of the rectangular shell, and the positions of the openings correspond to each other. A tungsten flow guide 113 is also provided in the rectangular shell. The thickness of the flow guide is ≤1mm. The flow guide includes two symmetrical arc-shaped shielding covers 1131 and a connecting cover 1132. The outer ends of the two arc-shaped shielding covers are respectively arranged above the openings of the two polytetrafluoroethylene plates and connected to the polytetrafluoroethylene plates. The inner ends of the two arc-shaped shielding covers are respectively connected to the two ends of the connecting cover. The flow guide cover and the rectangular shell do not touch each other. The flow guide cover is connected to the positive pole of the high-voltage power supply, and the rectangular shell is connected to the negative pole of the high-voltage power supply. The range of the high-voltage power supply is 3000 to 10000V. When the high-voltage power supply (alternating current) is working, corona discharge will occur between the positive and negative poles, and positive and negative ions will be continuously generated in the cavity between the two electrodes.

[0025] One opening of the aerosol mixing chamber is an air inlet, and the other opening is an air outlet. The air inlet is connected to the high-concentration aerosol. A servo loop is also provided between the air outlet and the air inlet. The servo loop includes a first high-efficiency filter 12, a servo air pump 13, an electronic flow control valve 14 and a second high-efficiency filter 15 connected in sequence; wherein the first high-efficiency filter 12 and the second high-efficiency filter 15 are filters with a filtration efficiency of 99.999% for 0.3 micron particles. The air outlet, the servo air pump and the electronic flow control valve are all connected to a flow servo controller (not shown in the figure).

[0026] The aerosol at the air outlet of the aerosol mixing chamber is divided into two paths, one path is the diluted aerosol, and the other path of aerosol passes through the first high-efficiency filter, the servo air pump, the electronic flow control valve and the second high-efficiency filter to form clean air and then enter the aerosol mixing chamber together with the high-concentration aerosol to mix. The flow servo controller automatically adjusts the operation of the servo air pump 13 and the electronic flow control valve 14 according to the preset data of the sampling flow rate and the aerosol dilution ratio required by the analysis and testing equipment, so that the clean air formed enters the aerosol mixing chamber together with the high-concentration aerosol at a certain flow rate to mix, and finally the diluted aerosol can meet the sampling requirements of the back-end analysis and testing equipment according to the preset dilution ratio and flow rate.

[0027] For example, when the sampling volume of conventional aerosol analysis and testing equipment is 1L / min (i.e. the flow rate of the aerosol after dilution is 1L / min), in order to achieve a 1000-fold dilution ratio, the flow rate of the servo loop to form clean air needs to be controlled at a flow point of 0.999L / min. At this time, the intake flow rate of the high-concentration aerosol only needs to be 0.001L / min (this flow rate is an automatic supplement to the sampling volume of the analysis and testing equipment and the flow rate of the servo loop adjusted by the electronic flow control valve, and no manual adjustment is required). The flow ratio shows that the dilution ratio of the aerosol after passing through the dilution device is 1000:1.

[0028] For example, when the sampling volume of conventional aerosol analysis and testing equipment is 30L / min (i.e., the flow rate of the aerosol after dilution is 30L / min), in order to achieve a 1000-fold dilution ratio, the flow rate of the servo loop to form clean air needs to be controlled at a flow point of 29.97L / min. At this time, the intake flow rate of the high-concentration aerosol only needs to be 0.03L / min (this flow rate is an automatic supplement to the sampling volume of the analysis and testing equipment and the servo loop flow rate adjusted by the electronic flow control valve, and no manual adjustment is required). The flow ratio shows that the aerosol dilution ratio after passing through the dilution device is 1000:1.

[0029] According to the above example, for the back-end aerosol analysis test equipment, when the sampling flow rate is between 1 and 30 L / min, the servo loop forms a clean air flow control between 0.999 L / min and 29.97 L / min. The electronic flow control valve of this flow rate is easily available on the market.

[0030] After the clean air and high-concentration aerosol are mixed, they enter the aerosol mixing chamber through the air inlet. Due to the shielding of the arc-shaped shielding cover on the air inlet side, the mixed aerosol after entering flows along the arc wall, eventually forming a downward flipping flow of the aerosol, and then flows into the arc-shaped shielding cover on the air outlet side through the connecting cover. The airflow flows along the arc wall, forming an upward flipping airflow, and finally flows out through the air outlet.

[0031] The aerosol airflow entering the mixing chamber will flip downward and upward under the action of the arc-shaped shield. The flipped airflow forms a turbulent state, causing the airflow to continuously roll in a circular shape within the two arc-shaped shields, and forming a flip airflow similar to the "boiling line". This airflow state allows the clean air and high-concentration aerosol flowing into the mixing chamber to be fully mixed, obtaining the uniformly mixed diluted aerosol required for the test.

[0032] It should be noted that the reversal of the "boiling line" refers to the backflow of air flow under the action of air flow velocity, air flow gravity, inertia force and viscosity, forming a tumbling flow state similar to a "drum washing machine".

[0033] Preferably, when the arc angle of the arc-shaped shielding cover is in the range of 60° to 90°, the aerosol can be mixed more fully.

[0034] In addition, the high voltage applied to the arc-shaped shield and the rectangular shell will generate corona discharge between the positive and negative electrodes, thereby continuously generating positive and negative ions in the cavity between the two electrodes. Therefore, the aerosol flowing into the mixing chamber will reach the Boltzmann electrostatic equilibrium under the action of positive and negative ions, avoiding the migration and agglomeration of aerosols with a large amount of charge under the action of the charge force, ensuring the particle size and distribution of the original aerosol, and avoiding the possibility of causing large measurement errors in subsequent aerosol analysis and testing. In particular, when the high voltage power supply ranges from 6000 to 9000V, the effect produced is better.

[0035] Among them, aerosol Boltzmann electrostatic equilibrium means that the charges in the aerosol are in a stable state, there is no directional movement of charges in the aerosol to reach the electrostatic equilibrium state and it conforms to the Boltzmann distribution statistical law.

[0036] In order to ensure good discharge performance and better enable the passing aerosol to reach Boltzmann electrostatic equilibrium, the distance between the connecting cover and the bottom surface of the rectangular shell is in the range of 3 to 8 mm.

[0037] The device of the utility model can be applied to the sampling flow rate of the aerosol analysis system of 1-30L / min; the aerosol concentration dilution ratio can be adjusted within the range of 1-1000.

[0038] Those skilled in the art should recognize that the above embodiments are only used to illustrate the purpose of the present invention, and are not intended to limit the present invention. As long as they are within the essential scope of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An aerosol mixing chamber, comprising a rectangular housing, characterized in that: Polytetrafluoroethylene plates with openings are respectively provided on both sides of the rectangular shell, and a tungsten air deflector is also provided inside the rectangular shell. The air deflector includes two symmetrical arc-shaped shielding covers and a connecting cover. The outer ends of the two arc-shaped shielding covers are respectively arranged above the openings of the two polytetrafluoroethylene plates and connected to the polytetrafluoroethylene plates, and the inner ends of the two arc-shaped shielding covers are respectively connected to the two ends of the connecting cover; The deflector is connected to the positive pole of a high-voltage power supply, and the rectangular shell is connected to the negative pole of the high-voltage power supply. The voltage range of the high-voltage power supply is 3000 to 10000V.

2. The aerosol mixing chamber according to claim 1, characterized in that: The arc angle range of the arc-shaped shielding cover is 60° to 90°.

3. The aerosol mixing chamber according to claim 1, characterized in that: The distance between the connecting cover and the bottom surface of the rectangular shell is in the range of 3 to 8 mm.

4. The aerosol mixing chamber according to claim 1, characterized in that: The high voltage power supply ranges from 6000V to 9000V.

5. An aerosol dilution device, characterized in that: An aerosol mixing chamber comprising any one of claims 1 to 4, wherein one opening of the aerosol mixing chamber is an air inlet, and the other opening is an air outlet, the air inlet is connected to a high-concentration aerosol, and a servo loop is provided between the air outlet and the air inlet, wherein the servo loop comprises a first high-efficiency filter, a servo air pump, an electronic flow regulating valve, and a second high-efficiency filter connected in sequence; The air outlet, the servo air pump and the electronic flow regulating valve are all connected to a flow servo controller.

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