Source manufacturing device and method for radioactive aerosol filter material sample in atmospheric environment

Abstract

The invention relates to an environmental radioactivity monitoring device and method, in particular to a source preparation device and method for an atmospheric environment radioactive aerosol filter material sample, and aims to overcome the defects that in an existing source preparation device, a filter membrane is extremely easy to block, so that the timeliness is reduced, and an evaporation device is small in heating area and low in evaporation efficiency. The source preparation device comprises a particle extraction unit, an evaporation unit and a control unit, wherein the particle extraction unit comprises an extraction device and a pressure filtration device; the evaporation unit comprises a third shell, a second cover body and a heating device, an inner bottom plate and an outer bottom plate are arranged at the bottom of the third shell, the left side edge and the right side edge of the inner bottom plate are lowered towards the center in a gradient mode and arranged in a front-back inclined mode, and the heating device is arranged between the inner bottom plate and the outer bottom plate; the source preparation method is based on the source preparation device, all particulate matters are extracted through particulate matter extraction, pressure filtration and heating evaporation in sequence, and the measurement source is prepared.

Description

Technical Field

[0001] The invention relates to an environmental radioactivity monitoring device and method, and in particular to a source making device and method for atmospheric environment radioactive aerosol filter material samples. Background Art

[0002] The ultra-large flow aerosol sampler is a commonly used device in the monitoring of radioactive aerosols in the atmospheric environment. In order to reduce the filtration flow rate, improve the sampling efficiency, reduce the sampling pressure resistance, and reduce the suction power, a filter material with a larger area is generally used for filtration sampling. In order to improve the detection efficiency, the Chinese patents with publication numbers CN109490935A and CN109540618A both disclose a source making device and method for extracting particles from the filter material sample using a particle extraction method. They all use a washing method for particle extraction, and then filter the extracted suspension to collect the particles on the filter membrane; perform low-pressure distillation on the filtrate to extract solid dissolved matter, and then combine the particles and dissolved matter to make a source. Due to the large number of submicron fine particles in atmospheric aerosols, the filter membrane is very easy to clog during filtration, affecting the timeliness; and the existing evaporation device uses a flask and a heating jacket, which has a small heating area and low evaporation efficiency. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the existing source making device, that is, the filter membrane is very easy to be clogged, thereby reducing the timeliness, and the evaporation device has a small heating area and low evaporation efficiency, and to provide a source making device and method for atmospheric environment radioactive aerosol filter material samples.

[0004] To achieve the above objectives, the technical solutions provided by the present invention are as follows:

[0005] A source making device for atmospheric radioactive aerosol filter material samples, which is special in that it includes a particle extraction unit, an evaporation unit and a control unit, the particle extraction unit includes an extraction device and a pressurized filtration device; the extraction device includes a first cover, a first shell, a second shell, an agitator, a first power assembly and a second power assembly, the first cover is used to seal the first shell; the second shell is sleeved in the first shell, a gap is set between the side walls of the two, the second shell is connected to the first shell through a bearing assembly, and a plurality of through holes are provided on the side wall of the second shell below the bearing assembly; the output end of the first power assembly is connected to the second shell to drive the second shell to rotate around its central axis; the agitator is set in the second shell, the second power assembly is connected to the agitator, and the second power assembly is used to seal the first shell. to drive the agitator to work; a discharge port is arranged at the lower end of the first shell, the inlet of the pressure filtering device is connected to the discharge port through a connecting pipe, a valve A is arranged on the connecting pipe, the outlet of the pressure filtering device corresponds to the inlet of the evaporation unit, and a valve B is arranged at the outlet of the pressure filtering device; the evaporation unit comprises a third shell, a second cover body and a heating device, an inner bottom plate and an outer bottom plate are arranged at the bottom of the third shell, the left and right side edges of the inner bottom plate are inclined downward toward the center and are inclined front and back, the heating device is arranged between the inner bottom plate and the outer bottom plate, and is used for heating the inner bottom plate; the second cover body is arranged at the upper end of the third shell, and is used for sealing it; the control unit is connected to the first power assembly, the second power assembly, the pressure filtering device and the heating device, and is used for controlling their working states.

[0006] Furthermore, the first power assembly includes a dehydration motor and a belt, and the output end of the dehydration motor is connected to the second housing through the belt to drive the second housing to rotate around its central axis;

[0007] The second power assembly includes a stirring motor, which is arranged on the first cover body. The stirrer includes a stirring rod and a stirring blade. One end of the stirring rod passes through the first cover body and is connected to the output end of the stirring motor. The stirring blade is arranged at the other end of the stirring rod.

[0008] Furthermore, the pressurized filtration device includes a filter cartridge, a filter membrane and an air compressor. The upper end of the filter cartridge is provided with an inlet, the lower end is provided with an outlet, the filter membrane is provided at the lower part of the filter cartridge, and the output end of the air compressor is connected to the position of the filter cartridge above the filter membrane.

[0009] Furthermore, the evaporation unit further includes an exhaust pipe and an axial flow fan arranged on the second cover;

[0010] The heating device comprises a heating plate and a plurality of heating rods, the heating plate is attached to the lower surface of the inner bottom plate, a plurality of mounting holes are evenly arranged on the heating plate, and the plurality of heating rods are respectively arranged in the plurality of mounting holes; the heating plate is made of copper;

[0011] The slope angles of the left and right side edges of the inner bottom plate of the third shell toward the center are 2.5° to 5°, and the front and rear inclination angles are 5° to 10°.

[0012] Furthermore, the control unit is an electric control device, which is connected to a stirring motor, a dehydration motor, an air compressor, a heating device and an axial flow fan.

[0013] Furthermore, the first cover body is connected to the first shell body by bolts, and an O-ring is arranged between the first cover body and the upper end surface of the first shell body;

[0014] The bearing bush assembly comprises an upper bearing bush and a lower bearing bush arranged on the upper and lower sides of the belt, and an anti-overflow ring is installed below the lower bearing bush to prevent the liquid in the first shell from entering the lower bearing bush.

[0015] At the same time, a method for preparing a source of a radioactive aerosol filter material sample for an atmospheric environment is also provided. The method is based on the above-mentioned source preparation device for preparing a radioactive aerosol filter material sample for an atmospheric environment, and its special feature is that it includes the following steps:

[0016] Step 1, adding an atmospheric radioactive aerosol filter material sample, water and a surfactant into a second shell of an extraction device;

[0017] Step 2, starting the second power assembly, controlling the stirrer to stir, and using water and a surfactant to extract particulate matter in the atmospheric radioactive aerosol filter material sample to obtain a suspension;

[0018] Step 3, the suspension enters the first shell through the multiple through holes on the side wall of the second shell, and the valve A is opened to discharge the suspension into the pressure filtration device;

[0019] Step 4, starting the first power assembly to drive the second housing to rotate for centrifugal dehydration, and discharging the remaining suspension into a pressure filtration device;

[0020] Step 5, close valve A, open valve B, and use a pressure filter device to filter the suspension under pressure, the pressure filter device intercepts part of the particles, and allows the filtrate to flow into the third shell;

[0021] Step 6, heating the inner bottom plate of the third shell by a heating device to evaporate the filtered liquid to obtain residual particulate matter;

[0022] Step 7, combining part of the particles retained by the pressure filtration device with the residual particles to form a measurement source.

[0023] Furthermore, in step 5, the pressurized filtration device is used to perform pressure filtration on the suspension, specifically: starting the air compressor to pressurize the filter cartridge, so that the suspension is filtered through the filter membrane, and the filtrate enters the third housing;

[0024] Step 6 specifically includes: controlling the heating rod to heat the inner bottom plate of the third shell through the electronic control device, and starting the axial flow fan to increase the evaporation rate until the filtrate is evaporated to dryness to obtain residual particulate matter;

[0025] Step 7 specifically includes: combining the filter membrane of the pressure filtration device and part of the particles retained thereon with the residual particles to form a measurement source.

[0026] Further, in step 5, the working pressure of the pressure filtration device is 0.6 MPa;

[0027] In step 6, the inner bottom plate of the third shell is heated to a temperature of 300°C to 350°C.

[0028] Further, in step 2, the agitator speed is 500 to 800 rpm, and the total washing time is 200 to 400 seconds;

[0029] The stirring mode of the stirrer is: first accelerate for 5 seconds, rotate forward for 20 seconds, then decelerate for 5 seconds, and rotate reversely for 20 seconds, and this is a cycle;

[0030] In step 4, the time of centrifugal dehydration is 1 to 3 minutes, and the rotation speed of the second shell is 1200 to 1500 rpm.

[0031] Beneficial effects of the present invention:

[0032] 1. The source making device for atmospheric radioactive aerosol filter material samples of the present invention is provided with two power components in the extraction device, which respectively control stirring and dehydration, separate the two processes of stirring and dehydration, facilitate control and improve extraction efficiency; at the same time, a pressurized filtration device is provided to solve the problem of low filtration efficiency caused by fine particles blocking the filter membrane. The evaporation unit of the present invention adopts an inner bottom plate with a certain inclination angle, which is low in the middle and high on both sides, and has a certain slope, which is convenient for further evaporation treatment after the filtrate is effectively recovered, and convenient for collecting residual particles after evaporation.

[0033] 2. The dehydration motor of the first power assembly in the present invention controls the second shell through a belt, which significantly reduces the vibration and noise of the dehydration process, which is beneficial to the safety and health of the operators; the pressurized filtering device uses compressed air as the pressure source of the pressurized filtering device, and the working pressure is selected at about 0.6MPa, which is easy to use.

[0034] 3. The present invention uses the same electric control device to control the particle extraction unit and the evaporation unit, and the device is highly automated, which effectively improves the timeliness of the source. The present invention installs a heating plate under the inner bottom plate, which has high thermal conductivity, and the axial flow fan actively discharges steam, and the overall evaporation efficiency is high. Using this evaporation unit, the evaporation treatment of 10L of aqueous solution can be completed within 1.5 hours.

[0035] 4. The method for preparing a source of an atmospheric radioactive aerosol filter material sample of the present invention sequentially processes the atmospheric radioactive aerosol filter material sample through the steps of particle extraction, pressurized filtration and heated evaporation, and finally collects part of the particulate matter intercepted by the pressurized filtration and the residual particulate matter obtained by evaporating the filtrate to obtain a measurement source, thereby reducing the clogging of the filter membrane during filtration.

[0036] 5. In the method for preparing a source of radioactive aerosol filter material samples for the atmospheric environment of the present invention, the pressure of pressurized filtration, the heating temperature of the inner bottom plate, the speed and time of the agitator, and the speed and time of centrifugal dehydration are set. The various parameters cooperate with each other to improve the efficiency of source preparation and the recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0038] Description of reference numerals:

[0039] 11-stirring motor, 12-first cover, 13-O-ring, 14-upper bearing, 15-belt, 16-lower bearing, 17-anti-overflow ring, 18-second housing, 19-stirring rod, 110-first housing, 111-filter cartridge, 112-filter membrane;

[0040] 21-axial flow fan, 22-inner bottom plate, 23-heating plate, 24-heating rod, 25-third shell, 26-second cover;

[0041] 30-Electronic control device, 31-Dehydration motor, 32-Air compressor. DETAILED DESCRIPTION

[0042] The present invention provides a source making device for atmospheric environment radioactive aerosol filter material samples. Figure 1 As shown, it includes a particle extraction unit, an evaporation unit and a control unit, and the particle extraction unit includes an extraction device and a pressure filtering device.

[0043] The extraction device includes a first cover body 12, a first shell 110, a second shell 18, an agitator, a first power assembly and a second power assembly. The first cover body 12 is used to seal the shell. In this embodiment, the first cover body 12 and the first shell 110 are connected by bolts, and an O-ring 13 is arranged between the upper end surface of the first cover body 12 and the first shell 110.

[0044] The second shell 18 is coaxially sleeved in the first shell 110, with a gap set between the side walls. The second shell 18 is connected to the first shell 110 through a bearing assembly, and a plurality of through holes are provided on the side wall of the second shell 18 below the bearing assembly.

[0045] The first power assembly includes a dehydration motor 31 and a belt 15, one end of the belt 15 is sleeved on the outer wall of the second shell 18, the bearing assembly includes an upper bearing 14 and a lower bearing 16 arranged on the upper and lower sides of the belt 15, and an anti-overflow ring 17 is installed under the lower bearing 16 to prevent the liquid in the first shell 110 from entering the lower bearing 16; the output end of the dehydration motor 31 is connected to the other end of the belt 15, and the second shell 18 is driven to rotate around its central axis through the belt 15.

[0046] The second power component includes a stirring motor 11, which is arranged on the first cover body 12. The agitator includes a stirring rod 19 and a stirring blade. One end of the stirring rod 19 passes through the first cover body 12 and is connected to the output end of the stirring motor 11. The agitator is driven to work by the stirring motor 11; the stirring blade is arranged at the other end of the stirring rod 19 and is located in the second shell 18.

[0047] The pressurized filtration device includes a filter cartridge 111, a filter membrane 112 and an air compressor 32. The upper and lower ends of the filter cartridge 111 are respectively provided with an inlet and an outlet. The inlet of the filter cartridge 111 is connected to the discharge port provided at the lower end of the first shell 110 through a connecting pipeline. A valve A is provided on the connecting pipeline. The outlet of the filter cartridge 111 corresponds to the inlet of the evaporation unit and is provided with a valve B. The filter membrane 112 is provided at the lower part of the filter cartridge 111, and the output end of the air compressor 32 is connected to the position of the filter cartridge 111 above the filter membrane 112.

[0048] The evaporation unit includes a third shell 25, a second cover 26, and a heating device. The third shell 25 is a hollow structure, and an inner bottom plate 22 and an outer bottom plate are arranged at the bottom. The left and right edges of the inner bottom plate are inclined downward toward the center and are arranged to be inclined front and back. The slope angle of the left and right edges of the inner bottom plate 22 toward the center is 2.5° to 5°, that is, the angle between the left and right sides is 170° to 175°. In this embodiment, the front and back inclination is set to be high at the back and low at the front, and the inclination angle is 5° to 10°, which is convenient for the liquid to be concentrated in one position during evaporation and improves the collection efficiency of residual particulate matter. The third shell 25 and the inner bottom plate 22 are preferably made of corrosion-resistant metal. The second cover 26 is arranged at the upper end of the third shell 25 for sealing it; the heating device is arranged between the inner bottom plate 22 and the outer bottom plate for heating the inner bottom plate 22. In this embodiment, the heating device includes a heating plate 23 and multiple heating rods 24. The heating plate 23 is in contact with the lower surface of the inner bottom plate 22. Multiple mounting holes are evenly arranged on the heating plate 23. The multiple heating rods 24 are respectively arranged in the multiple mounting holes. The heating plate 23 is preferably made of copper.

[0049] In order to improve the evaporation efficiency, an exhaust pipe and an axial flow fan 21 are provided on the second cover 26 .

[0050] The control unit is configured as an electric control device 30 , which is connected to the stirring motor 11 , the dehydration motor 31 , the air compressor 32 , the heating device and the axial flow fan 21 , and controls the working states thereof.

[0051] The present invention is a method for preparing a source of a radioactive aerosol filter material sample in an atmospheric environment. First, a washing method is used to separate particulate matter from the filter material, extract the particulate matter, and obtain a suspension in which the particulate matter is dispersed. Then, pressure filtration is used to separate the particulate matter in the suspension to obtain a filtrate. Finally, an evaporation unit heats and evaporates the filtrate by high-power heating evaporation to collect residual particulate matter in the filtrate. Based on the above-mentioned source preparation device, the following steps are specifically included:

[0052] Step 1: Add the atmospheric radioactive aerosol filter material sample, water and surfactant into the second shell 18 of the extraction device.

[0053] Step 2, starting the second power assembly, controlling the stirrer to stir, and using water and a surfactant to extract particulate matter in the atmospheric radioactive aerosol filter material sample to obtain a suspension;

[0054] The agitator speed is 500-800 rpm, and the total washing time is 200-400 seconds;

[0055] The stirring mode of the stirrer is: first accelerate for 5s, rotate forward for 20s, then decelerate for 5s, and rotate reversely for 20s, and this is a cycle.

[0056] Step 3: The suspension enters the first housing 110 through the multiple through holes on the side wall of the second housing 18, and the valve A is opened to discharge the suspension into the pressure filtering device.

[0057] Step 4, start the first power assembly to drive the second housing 18 to rotate for centrifugal dehydration, and discharge the remaining suspension into the pressure filtration device; the time of centrifugal dehydration is 1 to 3 minutes, and the speed is 1200 to 1500 rpm.

[0058] Step 5, close valve A, open valve B, start the air compressor 32 to pressurize the filter cartridge 111, the working pressure of the filter cartridge 111 is 0.6 MPa; the suspension is filtered through the filter membrane 112, the filter membrane retains part of the particles, and the filtrate flows from the filter cartridge 111 into the third shell 25.

[0059] Step 6: The electric control device 30 controls the heating rod 24 to heat the inner bottom plate 22, and starts the axial flow fan 21 to increase the evaporation rate until the filtrate is evaporated to dryness to obtain residual particulate matter. The heating temperature of the inner bottom plate 22 is 300°C to 350°C.

[0060] Step 7: Combine the filter membrane 112 of the pressurized filtration device with the retained particulate matter and the residual particulate matter to form a measurement source, and measure the radionuclides in the aerosol. Since it is difficult to completely separate the particulate matter on the filter membrane 112, the filter membrane 112 is collected together to form a measurement source, and the composition of the filter membrane 112 itself has no effect on the measurement results of the radionuclides.

Claims

1. A source making device for atmospheric radioactive aerosol filter material samples, characterized in that: It includes a particle extraction unit, an evaporation unit and a control unit, wherein the particle extraction unit includes an extraction device and a pressure filtering device; The extraction device comprises a first cover (12), a first shell (110), a second shell (18), a stirrer, a first power assembly and a second power assembly, wherein the first cover (12) is used to seal the first shell (110); the second shell (18) is sleeved in the first shell (110), a gap is provided between the side walls of the two, the second shell (18) is connected to the first shell (110) via a bearing assembly, and a plurality of through holes are provided on the side wall of the second shell (18) below the bearing assembly; The output end of the first power assembly is connected to the second housing (18) to drive the second housing (18) to rotate around its central axis; The stirrer is arranged in the second housing (18), and the second power assembly is connected to the stirrer to drive the stirrer to work; The lower end of the first shell (110) is provided with a discharge port, the inlet of the pressure filter device is connected to the discharge port through a connecting pipeline, a valve A is provided on the connecting pipeline, the outlet of the pressure filter device corresponds to the inlet of the evaporation unit, and the outlet of the pressure filter device is provided with a valve B; The evaporation unit comprises a third shell (25), a second cover (26) and a heating device. An inner bottom plate (22) and an outer bottom plate are arranged at the bottom of the third shell (25). The left and right edges of the inner bottom plate (22) are inclined downward toward the center and are arranged in a front-back tilt. The heating device is arranged between the inner bottom plate (22) and the outer bottom plate and is used to heat the inner bottom plate (22). The second cover (26) is arranged at the upper end of the third shell (25) and is used to seal the third shell (25). The control unit is connected to the first power assembly, the second power assembly, the pressure filtering device and the heating device to control their working states.

2. The source making device for atmospheric radioactive aerosol filter material samples according to claim 1, characterized in that: The first power assembly comprises a dehydration motor (31) and a belt (15), wherein the output end of the dehydration motor (31) is connected to the second housing (18) via the belt (15) to drive the second housing (18) to rotate around its central axis; The second power assembly comprises a stirring motor (11), the stirring motor (11) is arranged on the first cover body (12), the stirrer comprises a stirring rod (19) and a stirring blade, one end of the stirring rod (19) passes through the first cover body (12) and is connected to the output end of the stirring motor (11), and the stirring blade is arranged at the other end of the stirring rod (19).

3. The source making device for atmospheric radioactive aerosol filter material samples according to claim 1 or 2, characterized in that: The pressurized filtering device comprises a filter cartridge (111), a filter membrane (112) and an air compressor (32); an inlet is arranged at the upper end of the filter cartridge (111), and an outlet is arranged at the lower end; the filter membrane (112) is arranged at the lower part of the filter cartridge (111); and an output end of the air compressor (32) is connected to a position of the filter cartridge (111) located above the filter membrane (112).

4. The source making device for atmospheric radioactive aerosol filter material samples according to claim 3, characterized in that: The evaporation unit further comprises an exhaust pipe and an axial flow fan (21) arranged on the second cover (26); The heating device comprises a heating plate (23) and a plurality of heating rods (24); the heating plate (23) is in contact with the lower surface of the inner bottom plate (22); a plurality of mounting holes are evenly arranged on the heating plate (23); and the plurality of heating rods (24) are respectively arranged in the plurality of mounting holes; the heating plate (23) is made of copper; The slope angle of the left and right edges of the inner bottom plate (22) of the third shell (25) toward the center is 2.5° to 5°, and the front and rear inclination angle is 5° to 10°.

5. The source making device for atmospheric radioactive aerosol filter material samples according to claim 4, characterized in that: The control unit is an electric control device (30), and the electric control device (30) is connected to the stirring motor (11), the dehydration motor (31), the air compressor (32), the heating device and the axial flow fan (21).

6. The source making device for atmospheric radioactive aerosol filter material samples according to claim 1, characterized in that: The first cover body (12) is connected to the first shell (110) by bolts, and an O-ring (13) is arranged between the first cover body (12) and the upper end surface of the first shell (110); The bearing assembly comprises an upper bearing (14) and a lower bearing (16) arranged on the upper and lower sides of the belt (15); an anti-overflow ring (17) is installed below the lower bearing (16) to prevent liquid in the first housing (110) from entering the lower bearing (16).

7. A method for preparing a source of a radioactive aerosol filter material sample for an atmospheric environment, based on the device for preparing a source of a radioactive aerosol filter material sample for an atmospheric environment as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, adding an atmospheric radioactive aerosol filter material sample, water and a surfactant into a second housing (18) of an extraction device; Step 2, starting the second power assembly, controlling the stirrer to stir, and using water and a surfactant to extract particulate matter in the atmospheric radioactive aerosol filter material sample to obtain a suspension; Step 3, the suspension enters the first housing (110) through the multiple through holes on the side wall of the second housing (18), and the valve A is opened to discharge the suspension into the pressure filtration device; Step 4, starting the first power assembly to drive the second housing (18) to rotate for centrifugal dehydration, and discharging the remaining suspension into a pressure filtration device; Step 5, close valve A, open valve B, and use a pressure filter device to filter the suspension under pressure, the pressure filter device intercepts part of the particles, and allows the filtrate to flow into the third shell (25); Step 6, heating the inner bottom plate (22) of the third shell (25) by a heating device to evaporate the filtered liquid to obtain residual particulate matter; Step 7, combining part of the particles retained by the pressure filtration device with the residual particles to form a measurement source.

8. The method for preparing a source of radioactive aerosol filter material samples for atmospheric environment according to claim 7, characterized in that: In step 5, the pressurized filtration device is used to perform pressure filtration on the suspension, specifically: starting the air compressor (32) to pressurize the filter cartridge (111), so that the suspension is filtered through the filter membrane (112), and the filtrate enters the third housing (25); Step 6 specifically comprises: controlling the heating rod (24) to heat the inner bottom plate (22) of the third shell (25) through the electric control device (30), and starting the axial flow fan (21) to increase the evaporation rate until the filtered liquid is evaporated to dryness, thereby obtaining residual particulate matter; Step 7 specifically includes: combining the filter membrane (112) of the pressure filtration device and part of the particles trapped thereon with the residual particles to form a measurement source.

9. The method for preparing a source of a radioactive aerosol filter material sample for an atmospheric environment according to claim 7 or 8, characterized in that: In step 5, the working pressure of the pressure filtration device is 0.6 MPa; In step 6, the inner bottom plate (22) of the third shell (25) is heated to a temperature of 300°C to 350°C.

10. The method for preparing a source of radioactive aerosol filter material samples for atmospheric environment according to claim 9, characterized in that: In step 2, the agitator speed is 500 to 800 rpm, and the total washing time is 200 to 400 seconds; The stirring mode of the stirrer is: first accelerate for 5 seconds, rotate forward for 20 seconds, then decelerate for 5 seconds, and rotate reversely for 20 seconds, and this is a cycle; In step 4, the time of centrifugal dehydration is 1 to 3 minutes, and the rotation speed of the second shell (18) is 1200 to 1500 rpm.

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