Automatic continuous detection device for atmospheric micro-particle concentration based on differential pressure method

Abstract

The present invention belongs to the technical field of measuring atmospheric particulate matter by differential pressure method, and proposes an automatic continuous detection device for the concentration of atmospheric micro-particulate matter based on the differential pressure method, which includes a sampling system, a filter membrane system rotatably matched with the sampling system, a clamping system for fixing the filter membrane system, a computer system electrically connected to the filter membrane system, and a control system electrically connected to the sampling system and the clamping system. The automatic continuous replacement of the filter membrane is realized by using the rotation function of the filter membrane system, and the filter membrane is fixed by using the principle of electromagnetic attraction when the electromagnetic clamp is energized. Subsequently, the flow air pump inhales atmospheric air at a fixed flow rate, so that the micro-particulate matter in the atmosphere settles on the filter membrane. The data of the pressure sensor is input into the computer system to obtain the final concentration of particulate matter in the atmosphere.

Description

Technical Field

[0001] The present invention belongs to the technical field of measuring atmospheric particulate matter by differential pressure method, and particularly relates to an automatic continuous detection device for atmospheric fine particulate matter concentration based on the differential pressure method. Background Technique

[0002] In the past decade, China's industrialization has developed rapidly, and the amount and types of dust generated in the workplaces of large, medium and small manufacturing industries have been increasing. The dust generated during the production and processing process will greatly affect the health of workers in the workplace. Therefore, many dust component and concentration detection devices have been continuously developed. However, due to the current technology's requirements for measuring the concentration and components of atmospheric dust, it is necessary to collect air samples for a long time, and manual operation and replacement of sampling equipment are required, resulting in increased labor costs for enterprises and disproportionate time costs and experimental outputs invested by scientific research institutions. To address the above problems, it is necessary to automate the sample collection dust detection instruments currently used in industrial workplaces and scientific research institutions, select a simpler detection method, continuously improve the automation level of the detection instruments, and thus liberate human resources and improve production and scientific research efficiency.

[0003] Currently, the common methods for monitoring atmospheric fine particulate matter in China mainly fall into two categories: manual monitoring and automatic monitoring. Manual monitoring mainly refers to the method of continuously extracting the atmosphere at a certain time interval (such as 24h) using an atmospheric fine particulate matter sampler, intercepting the fine particulate matter in the atmosphere with a glass fiber or polytetrafluoroethylene filter membrane, and then weighing it with an analytical balance. Although manual monitoring has the advantages of low cost and simple operation mode, it has problems such as measurement errors caused by the volatilization of semi-volatile components in atmospheric fine particulate matter after the filter membrane is exposed for a long time, and it is time-consuming and laborious.

[0004] The automatic monitoring method is a monitoring method that uses an automatic monitoring instrument to continuously sample and calculate the mass concentration. According to the measurement principle, it can be divided into the β-ray method, the oscillating microbalance method, the light scattering method, the differential pressure method, etc.

[0005] The basic principle of the β-ray method is to detect the mass concentration of atmospheric particulate matter by using the attenuation of the β-ray released by C14 by the particulate matter deposited on the filter membrane. This method has the advantages of high measurement accuracy, low maintenance volume and low cost, but its time resolution is relatively low, and usually only the hourly average value can be used.

[0006] The oscillating balance method is also known as the micro quartz oscillating balance method. Its principle is that when dusty air flows through the center of the oscillating tube from the filter membrane, the dust in the air will accumulate on the filter membrane, changing the mass of the oscillating system, and thus changing the natural frequency of the entire oscillating system. On this basis, by measuring the change in the vibration frequency of the conical quartz tube before and after the dusty air flow passes through, the mass of the dust attached to the filter membrane and the dust mass concentration can be calculated by the established mathematical model. The main advantages of this method are high sensitivity, high accuracy, and high time resolution. However, it has problems such as high maintenance cost, being restricted by adhesion and overload problems, and being greatly affected by humidity.

[0007] The light scattering method is a measurement method that uses the scattered light of ions to measure the particle size and number concentration of particulate matter within a certain particle size range, and then converts it into mass concentration through calibration. This method has high sensitivity and fast response speed, but the measurement accuracy is relatively low.

[0008] The basic principle of the differential pressure method is to use pressure sensors fixed on both sides of the filter membrane to monitor the change in pressure at both ends of the filter membrane during the sampling process in real time, and obtain the mass concentration of micro particulate matter in the detected atmosphere by the established mathematical model.

[0009] This method can obtain the dynamic pressure change process during the sample collection process, and continuously acquire data to more accurately correct the obtained results. This method has high sensitivity, high result accuracy, and low cost, but it takes a long time to obtain the results.

[0010] Based on the above background analysis and method analysis, the present invention will be based on the differential pressure method, and independently design and prepare an automatic continuous detection device for atmospheric micro particulate matter concentration based on the differential pressure method, which can realize functions such as continuous automatic measurement, data collection, and analysis of atmospheric particulate matter dust for nearly three hours. Summary of the Invention

[0011] The present invention aims to solve the problems described in the background technology, and provides an automatic continuous detection device for atmospheric micro particulate matter concentration based on the differential pressure method.

[0012] To achieve the above object, the present invention adopts the following technical solution: An automatic continuous detection device for atmospheric micro particulate matter concentration based on the differential pressure method, including a sampling system, a filter membrane system rotatably cooperating with the sampling system, a clamping system for fixing the filter membrane system, a computer system electrically connected to the filter membrane system, and a control system electrically connected to the sampling system and the clamping system.

[0013] The automatic continuous detection device for atmospheric micro particulate matter concentration based on the differential pressure method includes the following measurement steps:

[0014] Step 1: Place the above automatic continuous detection device in the measurement environment, expose the air flow sampling pipeline to the sampling environment. Under the control of the control system, the atmosphere containing dust particles is inhaled through the sampling head by the suction of the flow air pump. The micro-particles are screened when passing through the sampling head and uniformly pass through the upper air flow sampling pipe and the lower air flow sampling pipe during the inhalation process with a uniform flow rate of the flow air pump.

[0015] Step 2: The particles in the air sampling sample are intercepted, causing a difference in air pressure on both sides of the filter membrane. The pressure sensor obtains real-time data and transmits it to the computer system, and the change data of the pressure values on both sides of the filter membrane is obtained as the sampling time increases.

[0016] Step 3: The microcontroller controls the flow air pump to stop working, the electromagnetic clamp to release, the rotating motor to drive the rotating shaft and the filter membrane cassette to rotate 60°, then the electromagnetic clamp is closed again, and the flow air pump is started to realize the continuous automatic monitoring of the concentration of atmospheric micro-particles.

[0017] In a preferred embodiment of the present invention, the filter membrane system includes a circular filter membrane cassette. A plurality of circular filter membranes are arranged along the center of the filter membrane cassette. The filter membrane cassette is coaxially and fixedly connected with a rotating shaft, and the rotating shaft is connected with a driving member, and the driving member is electrically connected with the control system.

[0018] In a preferred embodiment of the present invention, the diameter of the filter membrane cassette is 120 mm and the height is 15 mm, and the diameter of the filter membrane is 30 mm and the height is 6 mm.

[0019] In a preferred embodiment of the present invention, a plurality of sockets are arranged on the filter membrane cassette. The clamping system includes electromagnetic clamps located above and below the filter membrane cassette. Plug shafts are fixedly connected to the electromagnetic clamps, and the plug shafts are vertically slidably matched with the plug holes. The electromagnetic clamps are electrically connected with the control system.

[0020] In a preferred embodiment of the present invention, the sampling system includes a sampling head and an upper air flow sampling pipe communicated with the sampling head. A lower air flow sampling pipe is arranged below the upper air flow sampling pipe. The lower air flow sampling pipe is communicated with the flow air pump. The filter membrane is located between the upper air flow sampling pipe and the lower air flow sampling pipe. Pressure sensors electrically connected with the computer system are fixedly connected in both the lower air flow sampling pipe and the upper air flow sampling pipe.

[0021] In a preferred embodiment of the present invention, one side of the filter membrane away from the rotating shaft extends 10 mm and penetrates through the filter membrane cassette.

[0022] In a preferred embodiment of the present invention, there are at least 6 filter membranes, and the interval angle between adjacent filter membranes is 60°.

[0023] In a preferred embodiment of the present invention, in Step 1, a hydrophobic filter screen is covered at the entrance of the sampling head.

[0024] In a preferred embodiment of the present invention, the measurement time for steps 1 to 3 is 30 minutes.

[0025] Principle and beneficial effects of the present invention: After inserting all filter membrane clips and setting various parameters of the device, the present invention can achieve continuous automatic monitoring for several hours. The filter membrane used for collection is automatically replaced through the filter membrane system at fixed intervals, and the collected filter membrane can be removed at any time and replaced with a new one to achieve longer and more accurate continuous monitoring. Combining with the differential pressure method, the device transmits the atmospheric pressure data on both sides of the filter membrane to the computer system in real time, so as to better obtain the dynamic change process of the air particulate matter concentration and perform synchronous calibration and comparison in combination with the results of subsequent laboratory filter membrane analysis.

[0026] The present invention has the following advantages: (1) It can achieve 3-hour continuous automatic monitoring, reduce operation steps, and improve efficiency; (2) The experimental results are accurate, and the measurement accuracy can be greatly improved after calibration; (3) The device is small in size, portable, and meets the outdoor measurement requirements; (4) The cost is low, and the only consumable is the filter membrane; (5) The measurement time can be set according to the actual real-time needs, providing more measurement range options.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Brief Description of the Drawings

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0029] Figure 1 is a schematic structural diagram of an automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method in an embodiment of the present application.

[0030] Reference numerals in the accompanying drawings of the specification include: rotary motor 1, filter membrane cassette 2, filter membrane 3, rotating shaft 4, sampling head 5, upper sampling air pipe 6, electromagnet 7, electromagnetic clamp 8, flow air pump 9, pressure sensor 10, microcontroller 11, power supply 12, computer system 13. Detailed Description of the Embodiment

[0031] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "vertical", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0033] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] This application provides an automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method, aiming to continuously detect the particle concentration in the atmosphere or air. Basically as shown in the attached Figure 1 figure, it includes a frame, on which a filter membrane 3 system is installed. The filter membrane 3 system includes a rotary motor 1 bolted and fixed to the frame. A rotating shaft 4 is coaxially bolted and fixed to the output shaft of the rotary motor 1. A circular filter membrane cassette 2 is coaxially fixed to the rotating shaft 4. The diameter of the filter membrane cassette 2 is 120 mm and the height is 30 mm. A number of through holes are provided on the filter membrane cassette 2, and a filter membrane 3 is vertically slidably arranged in the through holes. The diameter of the filter membrane 3 is 30 mm and the height is 6 mm. The side of the filter membrane 3 away from the rotating shaft 4 extends 10 mm. Of course, the values provided in this embodiment are all example values. In this embodiment, the number of filter membranes 3 is 6, and the interval between adjacent filter membranes 3 is 60°. Of course, the number of filter membranes 3 can also be 2, 4, 8, etc., and the adjacent angles can be changed according to the actual situation, that is, according to different designs, different numbers and angles are selected.

[0035] A sampling system is arranged on the frame. The sampling system includes a sampling head 5 bolted and fixed to the frame. A hydrophobic filter screen covers the sampling head 5. The diameter of the collected atmospheric micro-particles can be determined by changing the pore diameter of the hydrophobic filter screen. The sampling head 5 is connected to an upper sampling air pipe 6 located above the filter membrane 3. A lower sampling air pipe fixed to the frame is arranged below the filter membrane 3. Pressure sensors 10 are screwed and fixed in both the upper sampling air pipe 6 and the lower sampling air pipe. The lower sampling air pipe is connected to a flow air pump 9.

[0036] In this embodiment, an electromagnetic clamp 8 system is further included. The electromagnetic clamp 8 system includes electromagnetic clamps 8 installed above and below the filter membrane 3 and equipped with electromagnets 7. The upper electromagnetic clamp 8 and the lower electromagnetic clamp 8 are both equipped with insertion shafts, and the filter membrane cassette 2 is provided with insertion holes that are vertically slidably matched with the insertion shafts. There are 6 insertion holes, which correspond one-to-one with the number of filter membranes 3. In this embodiment, a control system installed on the frame is also included. The control system is a microcontroller 11, such as a single-chip microcomputer, a PLC controller, etc. The controller is electrically connected to a power supply such as a storage battery or a power source 12 for power supply. In this embodiment, the existing power source 12 is used to supply power to the rotary motor 1, the electromagnetic clamp 8, the flow air pump 9, and the computer, etc. The microcontroller 11 is electrically connected to the rotary motor 1, the electromagnetic clamp 8, and the flow air pump 9. A computer system 13 is also included. The computer system 13 is a computer (mainly performing functions such as process control, data storage, and processing), and the computer system 13 is electrically connected to the pressure sensor 10.

[0037] In this embodiment, the specific implementation method includes the following steps:

[0038] Step 1: Place the above-mentioned automatic continuous detection device in the measurement environment so that the air flow sampling pipeline is exposed to the sampling environment. Under the control of the microcontroller 11, the flow air pump 9 and the electromagnetic clamp 8 work. When the flow air pump 9 works, the atmosphere containing dust particles is inhaled through the sampling head 5 by the suction action of the flow air pump 9. The fine particles in the air are screened when passing through the sampling head 5 to obtain the particulate matter within the required particle size range, and uniformly pass through the air flow sampling pipeline during the inhalation process with a uniform flow rate of the flow air pump 9.

[0039] Step 2: During the process of passing through the filter membrane 3, the particulate matter in the air sampling sample is intercepted, causing a difference in air pressure on both sides of the filter membrane 3. At this time, the pressure sensor 10 obtains real-time data and transmits it to the calculation system, and finally obtains the change data of the pressure values on both sides of the filter membrane 3 as the sampling time increases, thus completing a sampling cycle.

[0040] Step 3: Subsequently, the microcontroller 11 controls the flow air pump 9 to stop working, the electromagnetic clamp 8 to loosen, and the rotary motor 1 to drive the rotating shaft 4 and the filter membrane cassette 2 to rotate by 60°. Then, the electromagnetic clamp 8 is closed again, and the flow air pump 9 is started to realize the continuous automatic monitoring of the concentration of atmospheric fine particles. The entire process from Step 1 to Step 3 takes 30 minutes.

[0041] In this embodiment, the rotation angle of the rotary motor 1, the start and stop time of the flow air pump 9, the power-on and power-off time of the electromagnetic clamp 8, etc. are all controlled by the microcontroller 11 to realize the automatic function of the device. In addition, the above parameters can be further adjusted by the computer system 13 according to different on-site situations to better meet the needs of on-site applications.

[0042] In the description of this specification, the descriptions referring to terms such as "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0043] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method, characterized in that, Comprising: A sampling system, including a sampling head (5) and an upper air flow sampling tube (6) communicating with the sampling head. A lower air flow sampling tube is arranged below the upper air flow sampling tube, and the lower air flow sampling tube communicates with a flow air pump (9). Pressure sensors (10) are fixedly connected in both the upper air flow sampling tube and the lower air flow sampling tube; A filter membrane system, including a circular filter membrane cassette (2). The diameter of the filter membrane cassette is 120 mm and the height is 15 mm. Six circular filter membranes (3) are arranged along the center of the filter membrane cassette. The interval angle between adjacent filter membranes is 60°. A rotating shaft (4) is coaxially and fixedly connected to the filter membrane cassette. One side of the filter membrane away from the rotating shaft extends 10 mm and penetrates the filter membrane cassette. The rotating shaft is connected to a driving member, and the driving member is electrically connected to a control system; A clamping system, including electromagnetic clamps (8) located above and below the filter membrane cassette. Plug shafts are fixedly connected to the electromagnetic clamps. Jacks for vertical sliding fit with the plug shafts are arranged on the filter membrane cassette. The electromagnetic clamps are electrically connected to the control system; A computer system, electrically connected to the pressure sensors, for receiving and processing pressure data; A control system, electrically connected to the flow air pump, the electromagnetic clamps and the driving member, for controlling the rotation of the filter membrane cassette, the closing and loosening of the electromagnetic clamps, and the start and stop of the flow air pump.

2. The automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method according to claim 1, characterized in that, Including the following measurement steps: Step 1: Place the device according to Claim 1 in a measurement environment, expose the air flow sampling pipeline to the sampling environment. Under the control of the control system, the atmosphere containing dust particles is inhaled through the sampling head by the suction of the flow air pump. Micro-particles are screened when passing through the sampling head and uniformly pass through the upper air flow sampling tube and the lower air flow sampling tube during the inhalation process with a uniform flow rate of the flow air pump; Step 2: Particles in the air sampling sample are intercepted, causing different air pressures on both sides of the filter membrane. The pressure sensors obtain real-time data and transmit it to the computer system, and the change data of the pressure values on both sides of the filter membrane with the increase of the sampling time is obtained; Step 3: The microcontroller controls the flow air pump to stop working, the electromagnetic clamps to loosen, the rotating motor to drive the rotating shaft and the filter membrane cassette to rotate 60°, then closes the electromagnetic clamps again and starts the flow air pump to realize continuous and automatic monitoring of the concentration of atmospheric micro-particles.

3. The automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method according to claim 2, characterized in that, In Step 1, a hydrophobic filter screen covers the inlet of the sampling head.

4. The automatic continuous detection device for atmospheric micro-particle concentration based on the differential pressure method according to claim 2, characterized in that, The measurement time for Steps 1 to 3 is 30 min.

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