A portable condensation growth counter

Abstract

The present invention provides a portable condensation growth counter, which includes a saturation chamber, a semiconductor refrigeration chip, a condensation chamber, an optical chamber, a flow rate regulation unit and a main control circuit board. The saturation chamber adopts a planar aerosol channel structure to provide saturated working fluid vapor for the aerosol. The semiconductor refrigeration chip is located between the saturation chamber and the condensation chamber to jointly control the temperature of the saturation chamber and the condensation chamber. The condensation chamber realizes the growth of the particle size to reach the micron level. The optical chamber counts and detects the grown particles. The flow rate regulation unit regulates the sampling flow rate. The main control circuit board uses the single particle counting mode to collect and calculate the particle number concentration in real time, and at the same time uses the photometer mode to integrate the pulse signal to evaluate the overall state of the optical chamber. The instrument is small in size and light in weight, and the working fluid can be selected as n-butanol or pure water, which broadens the application occasions of the instrument.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental monitoring, and in particular relates to a portable condensation growth counter. Background Art

[0002] When conducting portable measurements of particle number concentration, the light scattering method is often used to measure the particle size of particles larger than 300nm. This method cannot measure particles below 300nm.

[0003] Condensation growth counters are often used to measure small-size particles. Most of them are desktop instruments on the market, and their size and weight cannot meet the needs of portable observation. Patent application number 201810201191.6, "A small particle condensation growth counter", provides a small particle counter, but it has the following problems: first, there are many parts in the system, and the size and weight cannot meet the requirements; second, the evaporation chamber and condensation chamber are designed back to back, and the particles have a 180° turn inside, resulting in large particle losses. Portable particle counters on the market, such as the 3007 counter from TSI of the United States, have the following problems: First, the operating temperature range is 10-35°C, which is too narrow; second, the saturation chamber is soaked in isopropyl alcohol before use, and the working fluid cannot be stored internally, so the continuous use time is limited. When the particle size of the particles after growing in the condensation chamber is small due to insufficient isopropyl alcohol supply, it is easy to cause the problem of low total concentration; third, only semiconductor refrigeration chips are used internally to control the saturation chamber and the condensation chamber. Under different atmospheric ambient temperatures, the absolute temperatures of the saturation chamber and the condensation chamber will be different, and the absolute temperature will gradually drift, which will cause the lower limit of the particle size measurement to change accordingly. The specific relationship is that if the temperature difference between the saturation chamber and the condensation chamber is fixed, as the temperature of the saturation chamber increases, the minimum detection particle size will increase, and the accuracy of the instrument measurement will decrease; fourth, the working fluid cannot be replaced, and the use of isopropyl alcohol will be discharged into the air, causing air pollution, which limits its application occasions.

[0004] In individual exposure monitoring situations and monitoring situations such as clean rooms, the working fluid used in the condensation growth counter is often required to be non-polluting to the human body and the environment, thus limiting the use of instruments based on n-butanol or isopropanol as working fluid.

[0005] In summary, designing a particle number concentration measuring instrument with small size, low weight, low power consumption, wide temperature range, and the ability to use different working fluids for different scenarios has become an urgent problem to be solved. Summary of the invention

[0006] To overcome a series of defects existing in the prior art, the object of the present invention is to provide a portable condensation growth counter for the above problems, which includes a saturation chamber 1, a semiconductor refrigeration sheet 2, a condensation chamber 3, an optical chamber 4, a flow rate regulation unit 5 and a main control circuit board 6, and is characterized in that,

[0007] The saturation chamber 1 adopts a planar aerosol channel structure to provide saturated working fluid vapor for the aerosol;

[0008] The semiconductor refrigeration sheet 2 is located between the saturation chamber 1 and the condensation chamber 3 to jointly control the temperature of the saturation chamber 1 and the condensation chamber 3;

[0009] The condensation chamber 3 realizes the growth of the particle size to reach the micron level;

[0010] The optical chamber 4 counts and detects the grown particles;

[0011] The flow rate regulation unit 5 regulates the sampling flow rate;

[0012] The main control circuit board 6 uses the single particle counting mode to collect and calculate the particle number concentration in real time, and at the same time uses the photometer mode to integrate the pulse signal to evaluate the overall state of the optical chamber 4;

[0013] Based on the different working fluids used, the operation modes of the counter are divided into the n-butanol mode and the pure water mode.

[0014] Preferably, the saturation chamber 1 includes an aerosol inlet 1-1, a pressure measurement port 1-2, an upper cavity 1-3 of the saturation chamber, a lower cavity 1-4 of the saturation chamber, a liquid level observation window 1-5, a porous plate 1-6, a porous cotton 1-7, a liquid filling port 1-8, an aerosol channel 1-9, an aerosol outlet 1-10 of the saturation chamber and a heat insulating member 1-11. The aerosol enters the planar aerosol channel 1-9 from the aerosol inlet 1-1. In the aerosol channel 1-9, the temperature of the particles reaches the saturation chamber temperature and carries saturated working fluid vapor to flow out from the aerosol outlet 1-10 of the saturation chamber. Among them,

[0015] The upper cavity 1-3 and the lower cavity 1-4 of the saturation chamber are sealed by a sealing ring. The space formed between the upper cavity 1-3 and the lower cavity 1-4 of the saturation chamber includes a working fluid storage space, a filling space of the porous cotton 1-7 and the aerosol channel 1-9;

[0016] The liquid filling port 1-8 is used for injecting the working fluid. The liquid filling port 1-8 is a three-way structure, and its third port is connected to the pressure measurement port 1-2 to balance the pressure between the working fluid storage space and the aerosol channel 1-9;

[0017] The working fluid injected from the liquid filling port 1-8, a part of which is absorbed by the porous cotton 1-7, and the other part is stored in a fluid manner. The bottom liquid level is observed through the liquid level observation window 1-5;

[0018] A porous plate 1-6 is provided between the porous cotton 1-7 and the aerosol channel 1-9. While allowing the saturated working fluid vapor to pass through, it can ensure the height of the aerosol channel, prevent the porous cotton 1-7 from expanding due to the absorption of the working fluid and occupying the space of the aerosol channel 1-9, and at the same time reduce the loss of particulate matter in the aerosol channel 1-9;

[0019] The upper surface of the aerosol channel 1-9 is made of aluminum alloy, and the lower surface is the porous plate 1-6;

[0020] The saturated chamber 1 and the condensation chamber 3 are hermetically connected through the heat insulation member 1-11 and the sealing ring;

[0021] The saturated chamber 1 is made of aluminum alloy after oxidation treatment; the porous plate 1-6 is a thin plate structure made of stainless steel.

[0022] Preferably, the thermoelectric cooler 2 has a hollow structure, and heat-conducting silicone grease is coated on both sides. The cold surface of the thermoelectric cooler 2 is used to cool the condensation chamber 3, and the hot surface of the thermoelectric cooler 2 is used to heat up the saturated chamber 1; Thermistor sensors are installed on the surfaces of the saturated chamber 1 and the condensation chamber 3. The main control circuit board 6 continuously collects the temperature information of the thermistor sensors, and controls the operating power of the thermoelectric cooler 2 in a PWM manner to ensure that the temperature difference between the saturated chamber 1 and the condensation chamber 3 is equal to the set value.

[0023] Preferably, in the n-butanol mode, the temperature difference between the saturated chamber 1 and the condensation chamber 3 is maintained at 17 °C; in the pure water mode, the temperature difference between the saturated chamber 1 and the condensation chamber 3 is maintained at 45 °C;

[0024] In the pure water mode, because the mass diffusivity of water is slightly greater than the thermal diffusivity of air, the temperature of the saturated chamber 1 is higher than the atmospheric environment temperature, so the particulate matter will initially grow in the saturated chamber 1 and continue to grow in the condensation chamber 3; in the n-butanol mode, because the mass diffusivity of n-butanol is less than the thermal diffusivity of air, the particle size of the particulate matter does not change in the saturated chamber 1, and only grows in the condensation chamber 3.

[0025] Preferably, a cooling fan is arranged around the saturated chamber 1 to cool the saturated chamber 1 when the temperature of the saturated chamber 1 is too high; a thin film heating resistance sheet is arranged on the bottom surface of the saturated chamber 1 for auxiliary heating of the saturated chamber 1 in low-temperature situations.

[0026] Preferably, the condensation chamber 3 is a cylindrical aerosol channel structure. The inner surface of the condensation chamber 3 is lined with filter cotton that absorbs the working fluid. After the condensed working fluid is absorbed by the filter cotton, it flows back to the saturation chamber 1 under the action of gravity, preventing the aerosol passage from being blocked due to the condensation of the working fluid on the inner surface and the surface tension.

[0027] Preferably, an adiabatic nozzle 4-1 is provided between the optical chamber 4 and the condensation chamber 3. The adiabatic nozzle 4-1 is used to focus the particulate matter in the aerosol onto a detection area through a slit light source. When each particulate matter passes through, a pulse signal is formed on the photosensitive element. The typical half-peak width of the pulse signal is 400 ns and is counted by the high-speed counter of the main control circuit board 6. The main control circuit board 6 has a differential pressure sensor to measure the differential pressure at both ends of the adiabatic nozzle 4-1 and monitor the status information of the nozzle in real time.

[0028] Preferably, the height of the planar aerosol channel 1-9 in the saturation chamber is 2 mm and the width is 14 mm; the inner diameter of the condensation chamber 3 is 4.6 mm and the length is 40 mm; the aperture of the small hole after the adiabatic nozzle 4-1 contracts is 0.3 mm, and the inlet volume flow rate of the counter is 0.1 L / min.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1) In the present invention, the saturation chamber adopts a planar aerosol channel structure, which improves the utilization efficiency of the saturation chamber and reduces the volume of the saturation chamber; and there is a storage space for a certain amount of working fluid at the bottom of the saturation chamber;

[0031] 2) In the present invention, the total flow rate of the instrument is 0.1 L / min, the power consumption of the vacuum pump is low, and the consumption of the working fluid is small; at room temperature of 25 °C, the average power consumption in the n-butanol mode is 5 W; at room temperature of 25 °C, the average power consumption in the pure water mode is 20 W;

[0032] 3) In the present invention, the saturation chamber and the condensation chamber adopt a way of cooperative temperature control by a semiconductor refrigeration sheet, without a heat dissipation structure, which can save the power consumption of the instrument. At the same time, the saturation chamber has a cooling fan and an auxiliary thin film resistance heating sheet, which can adapt to the operation under wide temperature conditions and avoid the absolute temperature of both being at a relatively high or low level for a long time, affecting the lower limit of the minimum detectable particle size of the instrument;

[0033] 4) In the present invention, the working fluid can be selected to use n-butanol or pure water, greatly expanding the measurement occasions of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of a portable condensation growth counter of the present invention;

[0035] Figure 2Schematic diagram of the structure of the saturation chamber in a portable condensation growth counter of the present invention.

[0036] In the figure, the reference numerals are as follows:

[0037] 1: Saturation chamber; 2: Semiconductor refrigeration sheet; 3: Condensation chamber; 4: Optical chamber; 5: Flow regulation unit; 6: Main control circuit board;

[0038] 1-1: Aerosol inlet; 1-2: Pressure measurement port; 1-3: Upper cavity of the saturation chamber; 1-4: Lower cavity of the saturation chamber; 1-5: Liquid level observation window; 1-6: Porous plate; 1-7: Porous cotton; 1-8: Liquid filling port; 1-9: Aerosol channel; 1-10: Aerosol outlet of the saturation chamber; 1-11: Heat insulation part; 4-1: Heat insulation nozzle; Detailed implementation manners

[0039] To make the purpose, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.

[0040] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] The embodiments described below by reference to the accompanying drawings and directional terms are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0042] In a broad embodiment of the present invention, a portable condensation growth counter includes a saturation chamber 1, a semiconductor refrigeration sheet 2, a condensation chamber 3, an optical chamber 4, a flow regulation unit 5 and a main control circuit board 6, and is characterized in that

[0043] The saturation chamber 1 adopts a planar aerosol channel structure to provide saturated working fluid vapor for the aerosol;

[0044] The semiconductor refrigeration sheet 2 is located between the saturation chamber 1 and the condensation chamber 3 to jointly control the temperature of the saturation chamber 1 and the condensation chamber 3;

[0045] The condensation chamber 3 realizes the growth of the particle size of the particulate matter to reach the micron level;

[0046] The optical chamber 4 counts and detects the grown particulate matter;

[0047] The flow regulation unit 5 regulates the sampling flow rate;

[0048] The main control circuit board 6 uses the single-particle counting mode to collect and calculate the particulate matter number concentration in real time, and at the same time uses the photometer mode to integrate the pulse signal to evaluate the overall state of the optical chamber 4;

[0049] Based on the different working fluids used, the operating modes of the counter are divided into the n-butanol mode and the pure water mode.

[0050] Preferably, the saturation chamber 1 includes an aerosol inlet 1-1, a pressure measurement port 1-2, an upper cavity 1-3 of the saturation chamber, a lower cavity 1-4 of the saturation chamber, a liquid level observation window 1-5, a perforated plate 1-6, a porous cotton 1-7, a liquid filling port 1-8, an aerosol channel 1-9, an aerosol outlet 1-10 of the saturation chamber, and a heat insulation member 1-11. The aerosol enters the planar aerosol channel 1-9 from the aerosol inlet 1-1. After the temperature of the particulate matter in the aerosol channel 1-9 reaches the temperature of the saturation chamber, it carries the saturated working fluid vapor and flows out from the aerosol outlet 1-10 of the saturation chamber. Among them,

[0051] The upper cavity 1-3 of the saturation chamber and the lower cavity 1-4 of the saturation chamber are sealed by a sealing ring. The space formed between the upper cavity 1-3 of the saturation chamber and the lower cavity 1-4 of the saturation chamber includes a working fluid storage space, a filling space of the porous cotton 1-7, and the aerosol channel 1-9;

[0052] The liquid filling port 1-8 is used for injecting the working fluid. The liquid filling port 1-8 is a three-way structure, and its third port is connected to the pressure measurement port 1-2 to balance the pressure between the working fluid storage space and the aerosol channel 1-9;

[0053] The working fluid injected from the liquid filling port 1-8 is partly absorbed by the porous cotton 1-7, and the other part is stored in a fluid manner. The bottom liquid level condition is observed through the liquid level observation window 1-5;

[0054] A perforated plate 1-6 is provided between the porous cotton 1-7 and the aerosol channel 1-9. While allowing the saturated working fluid vapor to pass through, it can ensure the height of the aerosol channel, prevent the porous cotton 1-7 from expanding due to absorbing the working fluid and occupying the space of the aerosol channel 1-9, and at the same time reduce the loss of particulate matter in the aerosol channel 1-9;

[0055] The upper surface of the aerosol channel 1-9 is made of aluminum alloy material, and the lower surface is the perforated plate 1-6;

[0056] The saturation chamber 1 and the condensation chamber 3 are sealed and connected through the heat insulation member 1-11 and the sealing ring;

[0057] The saturation chamber 1 is made of aluminum alloy material after oxidation treatment; the perforated plate 1-6 is a thin plate structure made of stainless steel material.

[0058] Preferably, the thermoelectric cooler 2 has a hollow structure, and heat-conducting silicone grease is coated on both sides. The cold surface of the thermoelectric cooler 2 is used for cooling the condensation chamber 3, and the hot surface of the thermoelectric cooler 2 is used for heating the saturation chamber 1; Thermistor sensors are installed on the surfaces of the saturation chamber 1 and the condensation chamber 3. The main control circuit board 6 continuously collects the temperature information of the thermistor temperature sensors and controls the operating power of the thermoelectric cooler 2 in a PWM manner to ensure that the temperature difference between the saturation chamber 1 and the condensation chamber 3 is equal to the set value.

[0059] Preferably, in the n-butanol mode, the temperature difference between the saturation chamber 1 and the condensation chamber 3 is maintained at 17 °C; in the pure water mode, the temperature difference between the saturation chamber 1 and the condensation chamber 3 is maintained at 45 °C;

[0060] In the pure water mode, because the mass diffusivity of water is slightly greater than the thermal diffusivity of air, the temperature of the saturation chamber 1 is higher than the atmospheric environment temperature, so the particulate matter will initially grow in the saturation chamber 1 and continue to grow in the condensation chamber 3; in the n-butanol mode, because the mass diffusivity of n-butanol is less than the thermal diffusivity of air, the particle size of the particulate matter does not change in the saturation chamber 1, and only grows in the condensation chamber 3.

[0061] Preferably, a cooling fan is arranged around the saturation chamber 1 to cool the saturation chamber 1 when the temperature of the saturation chamber 1 is too high; a thin-film heating resistance sheet is arranged on the bottom surface of the saturation chamber 1 for auxiliary heating of the saturation chamber 1 in low-temperature situations.

[0062] Preferably, the condensation chamber 3 has a cylindrical aerosol channel structure, and filter cotton for absorbing the working fluid is laid on the inner surface of the condensation chamber 3. After the condensed working fluid is absorbed by the filter cotton, it flows back to the saturation chamber 1 under the action of gravity, preventing the working fluid from blocking the aerosol passage due to surface tension after condensing on the inner surface.

[0063] Preferably, an adiabatic nozzle 4-1 is provided between the optical chamber 4 and the condensation chamber 3. The adiabatic nozzle 4-1 is used to focus the particulate matter in the aerosol onto a detection area through a slit light source. When each particulate matter passes through, a pulse signal will be formed on the photosensitive element. The typical half-peak width of the pulse signal is 400 ns and is counted by the high-speed counter of the main control circuit board 6; The main control circuit board 6 has a differential pressure sensor to measure the differential pressure at both ends of the adiabatic nozzle 4-1 and monitor the status information of the nozzle in real time.

[0064] Preferably, the height of the planar aerosol channel 1-9 in the saturation chamber is 2 mm and the width is 14 mm; the inner diameter of the condensation chamber 3 is 4.6 mm and the length is 40 mm; the length is 40 mm; the aperture of the small hole after the adiabatic nozzle 4-1 contracts is 0.3 mm, and the inlet volume flow rate of the counter is 0.1 L / min.

[0065] The following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.

[0066] Figure 1 It is a schematic diagram of a portable condensation growth counter. Aerosols in the environment enter the instrument through the aerosol inlet 1-1, and then pass through the saturation chamber 1, the condensation chamber 3, the optical chamber 4, and the flow control unit 5 in sequence, and are discharged into the atmospheric environment.

[0067] The saturation chamber 1 is made of aluminum alloy treated by black oxidation, and mainly includes an aerosol inlet 1-1, a pressure measurement port 1-2, an upper cavity 1-3 of the saturation chamber, a lower cavity 1-4 of the saturation chamber, a liquid level observation window 1-5, a perforated plate 1-6, a perforated cotton 1-7, a liquid addition port 1-8, an aerosol channel 1-9, an aerosol outlet 1-10 of the saturation chamber, and a heat insulating member 1-11. After the aerosol enters from the aerosol inlet 1-1, it enters the aerosol channel 1-9. The aerosol channel 1-9 has a planar structure, and the upper and lower surfaces are respectively the upper cavity 1-3 of the saturation chamber and the perforated plate 1-6. After the aerosol passes through this part of the area, the temperature of the particulate matter reaches the temperature of the saturation chamber, and it will carry the saturated working fluid vapor and flow out from the aerosol outlet 1-10 of the saturation chamber.

[0068] The perforated plate 1-6 is a thin plate made of stainless steel structure, and the bottom is a perforated cotton 1-7 with a smooth surface. The area formed between the lower part of the perforated cotton 1-7 and the lower cavity 1-4 of the saturation chamber can be used to store the working fluid in a fluid state. Through the absorption of the perforated cotton 1-7, the saturated working fluid vapor of the aerosol is continuously supplied. The storage amount of the working fluid can be observed through the liquid level observation window 1-5. When the liquid level is low, the working fluid can be added through the liquid addition port 1-8. During the operation of the instrument, the liquid addition port 1-8 is blocked by a plug. Another three-way interface of the liquid addition port 1-8 is connected to the pressure measurement port 1-2 and the inlet of the absolute pressure sensor at the same time, so that the pressure is balanced.

[0069] The working fluid can choose to use n-butanol or pure water according to the needs of the measurement occasion. In the pure water mode, because the mass diffusivity of water is slightly greater than the thermal diffusivity of air, and the temperature of the saturation chamber 1 is higher than the atmospheric environment temperature, the particulate matter will grow initially in the saturation chamber 1; in the n-butanol mode, because the mass diffusivity of n-butanol is less than the thermal diffusivity of air, the particle size of the particulate matter does not change in the saturation chamber 1. At room temperature of 25°C, the average power consumption in the n-butanol mode is 5W; at room temperature of 25°C, the average power consumption in the pure water mode is 20W.

[0070] After the aerosol flows out from the aerosol outlet 1-10 of the saturation chamber, it passes through the heat insulator 1-11 and enters the aerosol pipeline of the condensation chamber 3. The condensation chamber 3 is a cylindrical pipeline with a length of 40 mm and an inner diameter of 4.6 mm. The inner surface is lined with filter cotton that absorbs the working fluid, which can absorb the condensed working fluid and return it to the saturation chamber 1 under the action of gravity, preventing the working fluid from condensing on the inner surface and blocking the aerosol passage under the action of surface tension.

[0071] At the outlet end of the condensation chamber 3, the gas flow is contracted to a small hole with a diameter of 0.3 mm through the adiabatic nozzle 4-1, which is used to focus the particulate matter in the aerosol on a detection area through a slit light source. When each particulate matter passes through, a pulse signal will be formed on the photosensitive element. The typical half-peak width of the pulse signal is 400 ns and is counted by the high-speed counter of the main control circuit board 6. The main control circuit board 6 has a differential pressure sensor to measure the differential pressure at both ends of the adiabatic nozzle 4-1 and monitor the status information of the nozzle in real time.

[0072] The outlet of the optical chamber 4 is successively connected to a high-efficiency filter, an orifice flowmeter, and a vacuum pump. The two differential pressure ports of the orifice flowmeter are connected to the main control circuit board 6 to measure the aerosol volume flow rate, and the volume flow rate is maintained at 0.1 L / min by adjusting the vacuum pump in a closed loop.

[0073] The functions of the main control circuit board 6 mainly include: temperature control of the saturation chamber 1 and the condensation chamber 3, temperature control of the optical chamber 4, pressure and differential pressure monitoring, data acquisition of particulate matter pulse signals, internal storage of data, etc. The main control circuit board 6 uses the single-particle counting mode to collect and calculate the particulate matter number concentration in real time, and at the same time uses the photometer mode to integrate the pulse signals to evaluate the overall status of the optical chamber 4.

[0074] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A portable condensation growth counter, comprising a saturation chamber (1), a semiconductor refrigeration sheet (2), a condensation chamber (3), an optical chamber (4), a flow rate regulation unit (5) and a main control circuit board (6). It is characterized in that The saturation chamber (1) adopts a planar aerosol channel structure to provide saturated working fluid vapor for the aerosol. The semiconductor refrigeration sheet (2) is located between the saturation chamber (1) and the condensation chamber (3) to jointly control the temperature of the saturation chamber (1) and the condensation chamber (3). The condensation chamber (3) realizes the growth of the particle size to reach the micron level. The optical chamber (4) counts and detects the grown particles. The flow rate regulation unit (5) regulates the sampling flow rate. The main control circuit board (6) uses the single-particle counting mode to collect and calculate the particle number concentration in real time, and at the same time uses the photometer mode to integrate the pulse signal to evaluate the overall state of the optical chamber (4). Based on different working fluids used, the operating mode of the counter is divided into the n-butanol mode and the pure water mode. The saturation chamber (1) includes an aerosol inlet (1-1), a pressure measurement port (1-2), an upper cavity of the saturation chamber (1-3), a lower cavity of the saturation chamber (1-4), a liquid level observation window (1-5), a porous plate (1-6), a porous cotton (1-7), a liquid filling port (1-8), an aerosol channel (1-9), an aerosol outlet of the saturation chamber (1-10) and a heat insulation part (1-11). The aerosol enters the planar aerosol channel (1-9) from the aerosol inlet (1-1). In the aerosol channel (1-9), the temperature of the particles reaches the saturation chamber temperature and carries saturated working fluid vapor and flows out from the aerosol outlet of the saturation chamber (1-10). Among them, The upper cavity of the saturation chamber (1-3) and the lower cavity of the saturation chamber (1-4) are sealed by a sealing ring. The space formed between the upper cavity of the saturation chamber (1-3) and the lower cavity of the saturation chamber (1-4) includes a working fluid storage space, a filling space for the porous cotton (1-7) and an aerosol channel (1-9). The liquid filling port (1-8) is used for injecting the working fluid. The liquid filling port (1-8) is a three-way structure, and its third port is connected to the pressure measurement port (1-2) to balance the pressure between the working fluid storage space and the aerosol channel (1-9). The working fluid injected from the liquid filling port (1-8), a part of which is absorbed by the porous cotton (1-7), and the other part is stored in a fluid manner. The bottom liquid level situation is observed through the liquid level observation window (1-5). A porous plate (1-6) is provided between the porous cotton (1-7) and the aerosol channel (1-9). While allowing the saturated working fluid vapor to pass through, it ensures the height of the aerosol channel, avoids the expansion of the porous cotton (1-7) due to the absorption of the working fluid and occupying the space of the aerosol channel (1-9), and at the same time reduces the loss of particles in the aerosol channel (1-9). The upper surface of the aerosol channel (1-9) is made of aluminum alloy, and the lower surface is a porous plate (1-6). The saturation chamber (1) and the condensation chamber (3) are sealed and connected through the heat insulation part (1-11) and a sealing ring. The saturation chamber (1) is made of oxidized aluminum alloy; the porous plate (1-6) is a thin plate structure made of stainless steel.

2. A portable condensation growth counter according to claim 1, characterized in that the semiconductor refrigeration sheet (2) has a hollow structure, and heat-conducting silicone grease is coated on both sides. The cold surface of the semiconductor refrigeration sheet (2) is used to cool the condensation chamber (3), and the hot surface of the semiconductor refrigeration sheet (2) is used to heat the saturation chamber (1); thermistor sensors are installed on the surfaces of the saturation chamber (1) and the condensation chamber (3), and the main control circuit board (6) continuously collects the temperature information of the thermistor temperature sensors, and controls the operating power of the semiconductor refrigeration sheet (2) in a PWM manner to ensure that the temperature difference between the saturation chamber (1) and the condensation chamber (3) is equal to the set value.

3. A portable condensation growth counter according to claim 2, characterized in that: In the n-butanol mode, the temperature difference between the saturation chamber (1) and the condensation chamber (3) is maintained at 17 °C; in the pure water mode, the temperature difference between the saturation chamber (1) and the condensation chamber (3) is maintained at 45 °C; In the pure water mode, because the mass diffusivity of water is slightly greater than the thermal diffusivity of air, the temperature of the saturation chamber (1) is higher than the ambient temperature, so the particulate matter will initially grow in the saturation chamber (1) and continue to grow in the condensation chamber (3); in the n-butanol mode, because the mass diffusivity of n-butanol is less than the thermal diffusivity of air, the particle size of the particulate matter does not change in the saturation chamber (1), and only grows in the condensation chamber (3).

4. A portable condensation growth counter according to any one of claims 1-3, characterized in that a cooling fan is arranged around the saturation chamber (1) to cool the saturation chamber (1) when the temperature of the saturation chamber (1) is too high; a thin film heating resistance sheet is arranged on the bottom surface of the saturation chamber (1) for auxiliary heating of the saturation chamber (1) in low-temperature occasions.

5. A portable condensation growth counter according to claim 4, characterized in that the condensation chamber (3) is a cylindrical aerosol channel structure, and a filter cotton for absorbing the working fluid is laid on the inner surface of the condensation chamber (3). After the condensed working fluid is absorbed by the filter cotton, it flows back to the saturation chamber (1) under the action of gravity, preventing the aerosol passage from being blocked by the condensed working fluid on the inner surface due to surface tension.

6. A portable condensation growth counter according to any one of claims 1-3, characterized in that the height of the planar aerosol channel (1-9) in the saturation chamber is 2 mm and the width is 14 mm; the inner diameter of the condensation chamber (3) is 4.6 mm and the length is 40 mm; the length is 40 mm; the inlet volume flow rate of the counter is 0.1 L / min.

Images