CN113933228B - Particle counter with early warning function and working mode judging method - Google Patents
Particle counter with early warning function and working mode judging method Download PDFInfo
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- CN113933228B CN113933228B CN202111112051.XA CN202111112051A CN113933228B CN 113933228 B CN113933228 B CN 113933228B CN 202111112051 A CN202111112051 A CN 202111112051A CN 113933228 B CN113933228 B CN 113933228B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1434—Optical arrangements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
- G01N15/0211—Investigating a scatter or diffraction pattern
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
- G01N15/075—Investigating concentration of particle suspensions by optical means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N2015/1486—Counting the particles
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Abstract
本发明提供一种粒子计数器，包括光路系统，气路系统，包括进气和出气机构，进气机构包括进气通道；散射光收集系统包括光电探测器，信号处理电路将光电流信号转化为电压脉冲信号，第一处理器对电压脉冲信号处理后进行粒子浓度计算，第二处理器对电压脉冲信号处理后进行粒子计数统计；控制系统用于接收第一处理器和/或第二处理器的信息和/或控制第一处理器和/或第二处理器。通过在气路系统中设置进气通道，第一处理器计算待测气体粒子浓度，判断粒子计数器是否存在污染，基于判断结果通入待测气体粒子或洁净气体，达到防止粒子计数器污染、保证计数准确度的目的。还提供一种工作模式判定方法，可提高粒子计数器准确度。
The present invention provides a particle counter, including an optical path system, an air path system, including an air intake and air outlet mechanism, the air intake mechanism including an air intake channel; the scattered light collection system includes a photoelectric detector, the signal processing circuit converts the photocurrent signal into a voltage pulse signal, the first processor calculates the particle concentration after processing the voltage pulse signal, and the second processor performs particle counting statistics after processing the voltage pulse signal; the control system is used to receive information from the first processor and/or the second processor and/or control the first processor and/or the second processor. By setting an air intake channel in the air path system, the first processor calculates the concentration of gas particles to be measured, determines whether the particle counter is contaminated, and introduces gas particles to be measured or clean gas based on the judgment result, thereby preventing the particle counter from being contaminated and ensuring the counting accuracy. A working mode determination method is also provided, which can improve the accuracy of the particle counter.
Description
Technical Field
The invention relates to the technical field of particle counters, in particular to a particle counter with an early warning function and a working mode judging method.
Background
The particle counter is a special instrument for testing the particle size and distribution of airborne dust particles, and is widely applied to the authorities of various provinces and markets, such as drug inspection stations, blood centers, epidemic prevention stations, disease control centers, quality supervision stations, and the like, and manufacturing enterprises and scientific research departments of electronic industry, pharmaceutical workshops, semiconductors, optical or precision machining, plastics, paint spraying, hospitals, environmental protection, inspection stations, and the like.
A particle counter is an instrument that counts dust particles using the scattering principle of light. Light scattering is related to factors such as particle size, wavelength of light waves, refractive index of particles, and absorption characteristics of particles for light. However, there is a fundamental rule in terms of scattered light intensity and particle size that the intensity of scattered light by particles increases as the surface area of the particles increases. The dust-containing gas with certain flow rate passes through a beam of strong light to make particles emit scattered light, and the scattered light is projected onto a photomultiplier tube through a condensing lens to change light pulses into electric pulses, and the particle number is obtained from the pulse number. The particle diameter is derived from the intensity of the scattered light of the particles as a function of the particle size. Thus, the measurement of the intensity of scattered light is a fundamental principle of a light scattering particle counter to estimate the size of particles.
In order to obtain accurate particle counting, in an ideal state, the particle counter is obtained by collecting scattered light of particles passing through a photosensitive area one by one during operation, if the concentration of the particles in the measured gas is large, the possibility that a plurality of particles enter the photosensitive area at the same time or exist in the photosensitive area at the same time is greatly improved, so that overlapping loss or loss error of the particle counter is caused, and thus measurement error of the particle counter is caused, and in extreme cases, when too many particles of the particles flow into a gas path of the particle counter, the cavity of the particle counter is even polluted.
Therefore, it is necessary to provide a particle counter with an early warning function, which can determine whether the concentration of particles in the measurement cavity of the particle counter exceeds the standard.
Disclosure of Invention
The invention provides a particle counter with an early warning function, which can judge whether the concentration of particles in a measurement cavity exceeds the standard or not, can process the particles in time, prevents the pollution of the particle counter and ensures the counting accuracy of the particle counter.
The invention also provides a working mode judging method of the particle counter, which can reduce the overlapping loss or loss error of the particle counter.
Other objects and advantages of the present invention will be further appreciated from the technical features disclosed in the present invention.
In order to achieve one or a part or all of the purposes or other purposes, the particle counter with the early warning function provided by the technical scheme of the invention comprises an optical path system, an air path system, a scattered light collecting system, a signal processing circuit and a first processor and a second processor, wherein the optical path system comprises a light source, the air path system comprises an air inlet mechanism and an air outlet mechanism, the air inlet mechanism comprises an air inlet channel used for introducing gas particles and/or clean gas to be detected, the scattered light collecting system comprises a photoelectric detector used for receiving scattered light, the signal processing circuit is connected with the output end of the photoelectric detector and converts collected photoelectric current signals into voltage pulse signals, the first processor and the second processor are respectively connected with the signal processing circuit, the first processor performs particle concentration calculation after processing the voltage pulse signals, the second processor performs particle counting after processing the voltage pulse signals, and the control system is used for receiving information of the first processor and/or the second processor and/or controlling the first processor and/or the second processor.
The method has the beneficial effects that the first processor is used for calculating the concentration of the gas particles to be detected, judging whether the concentration of the gas particles to be detected in the particle counter exceeds the preset standard, and introducing the gas particles to be detected or clean gas based on the judging result, so that the aims of preventing inaccurate counting caused by the concentration of the particle counter exceeding the preset standard and ensuring the counting accuracy of the particle counter are fulfilled.
The particle counter further comprises a signal acquisition circuit, wherein the signal acquisition circuit is connected with the output end of the signal processing circuit and is used for sampling the voltage pulse signal and converting the voltage pulse signal into a digital signal. The first processor and the second processor are connected with the signal processing circuit through the signal acquisition circuit. The signal acquisition circuit is an analog-to-digital conversion circuit. The technical scheme has the beneficial effects that the continuous signal in the analog form is converted into the discrete signal in the digital form through the signal acquisition circuit, so that the continuous signal is easier to store and process and is convenient for the processor to process. The first processor can be directly connected with the signal processing circuit through the signal acquisition circuit, and the first processor can also be connected with the signal processing circuit through the second processor after being connected with the signal acquisition circuit.
The signal processing circuit includes an amplifying circuit for amplifying the photocurrent signal.
The signal processing circuit further comprises a filtering circuit for filtering the interference signal.
And the first processor performs statistics and calculation on the digital signals acquired by the signal acquisition circuit to obtain the concentration of the gas particles to be detected.
The second processor includes at least one comparator and at least one counting channel. Preferably, the number of comparators is the same as the number of counting channels. The comparator is used for comparing the voltage pulse signals of the gas particles to be detected with the threshold voltages of particles with different preset particle sizes, and the counting channel counts the pulse signals meeting the threshold voltage standard after the comparison and calculation to obtain the particle number with the particle size corresponding to the threshold voltage.
In order to achieve one or a part or all of the above or other objects, a working mode determining method of a particle counter according to an embodiment of the present invention includes a step 1 of receiving gas particles to be measured, a step2 of detecting the concentration of the gas particles to be measured and obtaining gas particle concentration data to be measured, and a step3 of comparing the gas particle concentration data to be measured with a preset early warning concentration, and counting the gas particles to be measured and obtaining count data by the particle counter based on the gas particle concentration data to be measured being lower than the preset early warning concentration, or taking early warning measures based on the gas particle concentration data to be measured being higher than the preset early warning concentration.
The step 1 comprises the steps that a gas circuit system of a particle counter obtains the gas particles to be detected, the gas particles are conveyed to a scattered light collecting system, a photoelectric detector receives scattered light of the gas particles to be detected, the scattered light is converted into a photoelectric current signal, the photoelectric current signal is transmitted to a signal processing circuit, and the signal processing circuit converts the photoelectric current signal into a voltage pulse signal. The step 2 includes that a first processor of a particle counter measures the concentration of the gas particles to be measured according to the voltage pulse signal, and obtains concentration data of the gas particles to be measured. The step 3 includes that based on a comparison result of the gas particle concentration data to be detected and preset early warning concentration data, when the gas particle concentration to be detected is smaller than the preset early warning concentration, the particle counter continues to count particles, and when the gas particle concentration to be detected is not smaller than the preset early warning concentration, the input of the gas particles to be detected into an air inlet channel of the particle counter is stopped.
The technical scheme has the beneficial effects that the concentration data of the gas particles to be detected are compared with the preset value through the preset early warning concentration, and the particle counter is judged to be in a normal working state or the concentration in the cavity exceeds the preset concentration standard so that the counter cannot accurately count and even the cavity is in a pollution state, so that corresponding measures can be taken according to the judgment result, the inaccurate counting of the particle counter is avoided, and the accuracy of the particle counter is improved.
And the second processor of the particle counter counts the particle number of the gas particles to be detected according to the voltage pulse signal in step 2 and/or step 3. And when the concentration of the gas particles to be detected is not less than the preset early warning concentration, the second processor stops the particle counting or continues the counting, but the obtained counting data is used as invalid data.
Further, the working mode judging method of the particle counter further comprises the step 4 of cleaning a measuring cavity of the particle counter by inputting clean gas into the air inlet channel of the air path system after inputting the gas particles to be measured into the air inlet channel of the particle counter is stopped until the measuring cavity meets the preset standard measuring condition.
The clean gas at least partially coincides with the gas path of the gas particles to be measured in the gas path of the gas inlet mechanism, and as an alternative scheme, the clean gas and the gas particles to be measured share the gas inlet nozzle which is conveyed to the photosensitive area in the measuring cavity by the gas inlet mechanism and the gas outlet mechanism which removes the gas in the measuring cavity.
Compared with the prior art, the invention has the beneficial effects that:
1. According to the particle counter with the early warning function, the first processor is used for calculating the concentration of the particles of the gas to be detected, judging whether the concentration of the particles of the gas to be detected in the particle counter exceeds the preset standard, and introducing the particles of the gas to be detected or clean gas based on the judging result, so that the aims of preventing inaccurate counting caused by the concentration of the particles of the particle counter exceeding the preset standard and guaranteeing the counting accuracy of the particle counter are fulfilled.
2. According to the working mode judging method of the particle counter, the concentration data of the gas particles to be detected are compared with the preset value through the preset early warning concentration, and whether the particle counter is in a normal working state or a pollution state is judged, so that corresponding measures can be taken according to a judging result, inaccurate counting of the particle counter is avoided, and accuracy of the particle counter is improved.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings.
Drawings
In order to more clearly illustrate the technical solutions of specific embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.
Fig. 1 is a block diagram of a particle counter with early warning function according to a first embodiment of the present invention.
Fig. 2 is a block diagram of a gas circuit system of a particle counter according to a first embodiment of the present invention.
Fig. 3 is a block diagram of a gas circuit system of a particle counter according to a second embodiment of the present invention.
Fig. 4 is a block diagram of a particle counter with early warning function according to a third embodiment of the present invention.
Fig. 5 is a flowchart of a method for determining an operation mode of a particle counter according to a fourth embodiment of the invention.
Fig. 6 is a flowchart of a working mode determining method of a particle counter according to a fifth embodiment of the invention.
Detailed Description
The foregoing and other features, aspects, and advantages of the present invention will become more apparent from the following detailed description of a preferred embodiment, which proceeds with reference to the accompanying drawings. The directional terms, such as up, down, left, right, front or rear, etc., are presented in the following embodiments with reference to the attached drawings only. Thus, the directional terminology is used for purposes of illustration and is not intended to be limiting of the invention.
Fig. 1 and fig. 2 are block diagrams of a particle counter with early warning function and a gas circuit system thereof according to a first embodiment of the present invention. Referring to fig. 1 and 2 in combination, the particle counter of the present embodiment includes an optical path system, an air path system, a scattered light collecting system, a signal processing circuit 5, a signal collecting circuit 6, a first processor 7 and a second processor 8, and a control system 9.
The optical path system of the present embodiment includes a light source 11, an optical shaping mechanism 12, and an optical trap 13. The light source 11 may be a laser light source, and is configured to provide a laser beam, and the laser beam is shaped by the optical shaping mechanism 12 and then output to form an optical path. The optical shaping mechanism 12 may be one or more of an aspherical lens, a cylindrical mirror, a diaphragm, etc., and is aimed at shaping a laser beam, eliminating side lobes of the beam, shaping a gaussian-distributed laser beam into a flat-top beam with uniform energy distribution, improving the performance of a light source for subsequent use, and absorbing the beam by an optical trap 13 disposed behind a photosensitive region in the beam propagation direction.
The gas circuit system includes a gas inlet mechanism and a gas outlet mechanism 32. The gas inlet mechanism further includes a gas particle inlet channel 311, a gas particle inlet switch 312, a clean gas inlet channel 313, and a clean gas inlet switch 314. The gas particles to be measured are the gas containing the particles to be measured, the gas inlet switch 312 of the gas particles to be measured is opened, the gas particles to be measured enter the gas inlet channel 315 and enter the photosensitive area 4 through the gas inlet nozzle 316 and are output through the gas outlet mechanism 32, and the gas path formed by the gas output by the gas inlet channel 315 and the light path output through the shaping of the optical shaping mechanism 12 form the photosensitive area 4 together. The clean gas inlet switch 314 is used for switching the clean gas inlet channel 313, so as to realize the input of clean gas into the gas inlet channel 315. The gas particle inlet switch 312 and the clean gas inlet switch 314 are not simultaneously opened, however, in other embodiments, the two switches 312 and 314 may be always opened, and only the gas particle to be detected and the clean gas are required to be introduced at different times.
The on/off of the gas particle inlet switch 312 and the clean gas inlet switch 314 can be controlled by manually operating the on/off of the switch to input the gas particles or clean gas to be measured, or the signals of the gas particle inlet switch 312 and the clean gas inlet switch 314 to be measured are connected to a control system, and the control system controls the on/off of the gas particle inlet switch 312 and the clean gas inlet switch 314 to control the input of the gas particles or clean gas to be measured.
Further, the air inlet mechanism of other embodiments optionally includes an air inlet flow rate adjustment mechanism, such as a flow rate adjustment valve, which is signally connected to a control system that adjusts the air inlet flow rate according to preset conditions.
The scattered light collection system comprises a photodetector 21 and a light mirror 22. The gas particles to be measured are scattered in the photosensitive region 4, and the scattered light is received by the photodetector 21 and converted into a photocurrent signal directly or after being reflected by the light reflecting mirror 22.
The signal processing circuit 5 is connected to the output terminal of the photodetector 21, and converts the photocurrent signal into a voltage pulse signal. In this embodiment, the signal processing circuit 5 includes an amplifying circuit and a filtering circuit, and the photocurrent signal is converted into a voltage pulse signal after the amplifying circuit amplifies and the filtering circuit filters out the interference signal. The invention does not limit the sequence of amplifying and filtering.
The signal acquisition circuit 6 is connected to the output end of the signal processing circuit 5, samples the voltage pulse signal and converts the voltage pulse signal into a digital voltage pulse signal, and the signal acquisition circuit 6 may be an analog-to-digital ADC conversion circuit, for example.
The first processor 7 and the second processor 8 are connected to the signal acquisition circuit 6. The first processor 7 is a concentration monitoring device, and is configured to receive the digital voltage pulse signal, and perform statistics and calculation to obtain the concentration of the gas particles to be detected. Alternatively, the first processor is used for calculating the average value by dividing the voltage amplitude acquired by the signal acquisition circuit by the acquired time in an accumulated manner, and then calculating the concentration data by combining the preset particle size and density parameters.
The second processor 8 is a counting and monitoring device, and is used for receiving the digital voltage pulse signals and processing to obtain the counting data of the number of the gas particles to be detected. In this embodiment, the second processor 8 may include a plurality of comparators and a plurality of counting channels, where the number of comparators is preferably consistent with the number of counting channels, and the plurality of comparators count the particles reaching the threshold voltage standard by comparing the voltage amplitude of the digital voltage pulse signal of the gas particles to be measured with the threshold voltage with the counting channel of the maximum threshold voltage, so as to obtain the corresponding number of particles with different particle sizes, and realize the function of counting the particles with different particle sizes. In other embodiments, the second processor 8 may integrate the voltage amplitude of the voltage pulse signal of the particle to be detected with the time span to obtain an integral value of the particle, and compare the integral value of the particle to be detected with the integral value of the standard particle with each particle size to obtain the number of particles with different particle sizes, so as to realize the counting function of the particles with different particle sizes.
The first processor 7 transmits the gas particle concentration to be measured and the second processor 8 transmits the count data to the control system 9. The control system 9 performs contrast analysis on the particle concentration of the gas to be detected and the pre-set pre-warning concentration parameter in the control system, when the particle concentration data is smaller than the pre-warning concentration, the control system 9 controls the second processor 8 to continue particle counting, when the particle concentration data is larger than or equal to the pre-warning concentration, the control system 9 controls the second processor 8 to stop particle counting, or marks the counting data of the second processor 8 based on a contrast analysis result, when the particle concentration of the gas to be detected is larger than or equal to the pre-set pre-warning concentration parameter, marks the counting data of the second processor 8 as invalid data, and when the particle concentration of the gas to be detected is smaller than the pre-set pre-warning concentration parameter, marks the counting data of the second processor 8 as valid data or not.
In addition, when the comparison analysis shows that the concentration of the particles of the gas to be detected exceeds the preset early warning concentration parameter, the control system 9 can also control to stop inputting of the particles of the gas to be detected, clean gas is input into the measuring cavity of the particle counter through the clean gas inlet nozzle instead, the first processor 7 continuously monitors the concentration data in the measuring cavity of the particle counter until the measuring cavity meets the preset clean standard, and then the control system 9 controls the clean gas to stop inputting, continues inputting of the particles of the gas to be detected and performs concentration detection and particle counting.
The technical scheme has the beneficial effects that by arranging two air inlet channels in the air channel system of the particle counter, the first processor 7 calculates the particle concentration of the gas to be detected, and inputs the particle concentration of the gas to be detected into the control system 9 to be compared with the pre-set early warning concentration in the control system 9, so as to judge whether the particle counter is polluted or not, and based on the judgment result, different air inlet channels of the air inlet mechanism are opened, thereby achieving the purposes of preventing the inaccurate counting condition caused by the pollution of the particle counter and ensuring the counting accuracy of the particle counter.
Fig. 3 is a block diagram of a gas circuit system of a particle counter according to a second embodiment of the present invention. Unlike the first embodiment, the air intake mechanism does not include an independently opened and closed air intake passage for the particles to be tested, an air intake opening for the particles to be tested, a clean air intake passage and an air intake opening for the clean air, but is connected to the air intake passage 315 by a gas particle filter 317, when the particles to be tested enter the air intake passage 315 through the gas particle filter 317, the gas particle filter 317 in an operating state can filter the particles in the particles to be tested to obtain clean air, and then the clean air is supplied to the air intake passage 315 when the gas particle filter 317 is connected to the air intake passage and the particle filtering operation is started, and when the gas particle filter 317 is connected to the air intake passage but the particle filtering operation is not started, the particles to be tested are supplied to the air intake passage 315. In other embodiments, the gas particle filter 317 is detachably connected to the gas channel 315, and when the gas particles to be measured are input, the gas particle filter 317 is disconnected from the gas channel 315, and when the clean gas is input, the gas particle filter 317 is kept connected to the gas channel 315 and works, so that the input function of the gas particles to be measured and the clean gas is realized, and the structure is simple.
Fig. 4 is a block diagram of a particle counter with early warning function according to a third embodiment of the present invention. The difference from the first embodiment is that the first processor 7 is connected to the output end of the second processor 8, and concentration data is obtained in real time for the number of the gas particles to be measured counted in the second processor 8 and the particle size statistics combined density.
In other embodiments, the second embodiment and the third embodiment may be combined to obtain a particle counter with an early warning function.
Fig. 5 is a flowchart of a method for determining an operation mode of a particle counter according to a fourth embodiment of the present invention. The operation mode determination method is operated based on the particle counter in the first to third embodiments.
Referring to fig. 5, the method for determining an operation mode of a particle counter according to the present embodiment includes step 1, receiving gas particles to be measured. Specifically, to-be-detected gas particles are input into an air inlet channel of the particle counter air circuit system, an air flow output by an air inlet nozzle of the air inlet channel and an optical path form a photosensitive area together, the to-be-detected gas particles are scattered in the photosensitive area, scattered light is received by a photoelectric detector in a scattered light collecting system and is converted into a photoelectric current signal, and the photoelectric current signal is converted into a voltage pulse signal through a signal processing circuit. Further, the voltage pulse signal can be converted into a digital voltage pulse signal which is easier to process through the signal acquisition circuit.
And 2, monitoring the concentration of the gas particles to be detected and obtaining the concentration data of the gas particles to be detected. The first processor is used for measuring the concentration of the gas particles to be measured according to the voltage pulse signals or the digital voltage pulse signals and obtaining the concentration data of the gas particles to be measured. At this time, according to the voltage pulse signal or the digital voltage pulse signal, the second processor may directly start counting the gas particles to be measured.
And step 3, comparing the gas particle concentration data to be detected with the preset early warning concentration, and counting the gas particles to be detected by the particle counter and obtaining counting data based on the fact that the gas particle concentration data to be detected is lower than the preset early warning concentration, or taking early warning measures based on the fact that the gas particle concentration data to be detected is higher than the preset early warning concentration.
The step 3 specifically includes that when the concentration of the gas particles to be detected is smaller than the preset early warning concentration, the second processor continues to count the gas particles to be detected, and the count data of the second processor is included in the data of normal particle counting operation, namely the effective data. When the concentration of the gas particles to be detected is not less than the preset early warning concentration, the input of the gas particles to be detected into the air inlet channel of the particle counter is stopped, at this time, the control system can control the second processor to continuously count or stop counting, but the counting data is included in the data for stopping normal particle counting, namely invalid data.
And 4, after stopping inputting the gas particles to be detected into the gas inlet channel of the particle counter, cleaning the measurement cavity of the particle counter by inputting clean gas into the gas inlet channel until the measurement cavity of the particle counter meets the preset standard measurement condition, namely, the first processor still works until the measured concentration data in the measurement cavity meets the reference value of the clean gas. In addition, the second processor can also work at the same time to measure the technical data in the measuring cavity until the standard measuring condition is met. The particle counter side may restart and begin cycling through the operations of steps 1-4.
Fig. 6 is a flowchart of a method for determining an operation mode of a particle counter according to a fifth embodiment of the present invention. Referring to fig. 6, the difference between the embodiment and the embodiment is that in the step 2, the second processor is not started to perform particle counting on the gas particles to be detected, but based on the comparison result of the gas particle concentration to be detected and the preset pre-warning concentration in the step 3, it is determined whether to start the second processor to perform particle counting.
The sixth embodiment of the invention is further optimized on the basis of the fourth embodiment and the fifth embodiment. Specifically, the preset early warning concentration in this embodiment includes a plurality of early warning concentration values, and a gas flow or flow rate control device is disposed in the air inlet mechanism, and the control system controls the gas flow or flow rate control device in the air inlet mechanism to control the adjustable air inlet flow or flow rate of the air inlet mechanism. For example, the first pre-warning concentration, the second pre-warning concentration, the X-n pre-warning concentration, the X pre-warning concentration, etc., n < X, X >1, the pre-warning concentration may be set according to a reference particle concentration of a space environment used by the particle counter, a gradient concentration pre-warning parameter of a preset unit volume particle concentration, and a pre-warning concentration parameter of a particle counter measuring a contaminated cavity, wherein the gradient concentration pre-warning parameter of the preset unit volume particle concentration includes a pre-warning concentration preset to generate a measurement error, and the pre-warning concentration is set in a ratio of the pre-warning concentration preset to generate the measurement error, that is, the ratio is set to be less than 1, for example, 0.5, 0.6, 0.7, 0.8, 0.9, etc., and the ratio is preset according to an actual situation. When the concentration of the gas particles to be measured is more than or equal to the early warning concentration parameter of the particle counter for measuring the pollution of the cavity, clean gas is introduced into the cavity for cleaning the cavity, when the concentration of the gas particles to be measured reaches the X-n early warning concentration of the preset early warning concentration value of the measurement error but is smaller than the preset early warning concentration of the measurement error, the first processor and the second processor work normally, the control system controls the air inlet mechanism to reduce the flow rate or flow rate of the gas particles to be measured in the air inlet channel, the measurement error is reduced by reducing the inlet amount of the gas particles to be measured in unit time, and when the early warning concentration of the preset measurement error is less than or equal to the early warning concentration parameter of the particle counter for measuring the pollution of the cavity, the clean gas can not be introduced into the cavity for cleaning the measurement, but the control system of the particle counter is used for improving the accuracy of the data of the particle counter by calculating and removing the data when the early warning concentration of the preset measurement error is less than or equal to the concentration of the gas particles to be measured. Specifically, when the pre-set early warning concentration of the measurement error is less than or equal to the concentration of the gas particles to be measured, the particle counter can stop the counting operation of the second processor, although the gas circuit system still introduces the gas particles to be measured, the control system calculates the relevant data segments (such as the duration of the period and the volume of the introduced gas) for removing the counting operation of the particle counter to stop the counting operation of the particle number during the calculation, so as to realize the effective counting of the particle counter, or the counting operation of the second processor is still performed, but the counting number of the segments is marked as abnormal data, and is cut off by the normal particle counting process together with the other relevant calculation parameters, and the counting operation of the particle number is not incorporated, so that the overlapping loss or the loss error of the particle counter can be reduced, or the control system can adjust the volume of the introduced gas particles to be measured, such as the air inlet flow rate of the gas particles to be measured, the pressure of the gas particles to be measured for discharging the gas particles to be measured with the super-warning concentration is reduced, and the concentration monitoring and the number counting of the gas particles to be measured can be continuously counted.
The foregoing description is only illustrative of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, i.e., all simple and equivalent changes and modifications that may be made in accordance with the claims and specification are intended to be included within the scope of the invention as defined by the appended claims. Furthermore, not all of the objects, advantages, or features of the present disclosure are required to be achieved by any one embodiment or claim of the present disclosure. Furthermore, the abstract sections and the invention names are used solely to assist patent document retrieval and are not intended to limit the scope of the claims. Furthermore, references to "first," "second," etc. in this specification or in the claims are only intended to name an element or distinguish between different embodiments or ranges, and are not intended to limit the upper or lower limit on the number of elements.
Claims (9)
1. A particle counter with early warning function, comprising:
an optical path system including a light source;
the gas path system comprises a gas inlet mechanism and a gas outlet mechanism, wherein the gas inlet mechanism comprises a gas inlet channel and is used for introducing gas particles to be detected and/or clean gas;
A scattered light collection system comprising a photodetector for receiving scattered light;
the signal processing circuit is connected with the output end of the photoelectric detector and converts the collected photoelectric current signal into a voltage pulse signal;
The first processor is used for calculating the particle concentration after processing the voltage pulse signal, and the second processor is used for counting particles after processing the voltage pulse signal;
a control system for receiving information of the first processor and/or the second processor and/or controlling the first processor and/or the second processor;
the photoelectric detector receives scattered light of the gas particles to be detected, converts the scattered light into a photoelectric current signal and transmits the photoelectric current signal to the signal processing circuit;
The second processor comprises at least one comparator and at least one counting channel, wherein the number of the comparators is the same as the number of the counting channels;
The first processor transmits the concentration of the gas particles to be detected and the second processor transmits counting data to the control system; the control system compares and analyzes the particle concentration of the gas to be detected with the pre-set early warning concentration parameter in the control system, and when the particle concentration data is smaller than the early warning concentration, the control system controls the second processor to continue particle counting;
The early warning concentration parameter is a reference particle concentration parameter of a space environment when the particle counter is used, or a gradient concentration early warning parameter of a preset unit volume particle concentration, or an early warning concentration parameter of a polluted particle counter measuring cavity.
2. The particle counter with the early warning function according to claim 1, further comprising a signal acquisition circuit, wherein the signal acquisition circuit is connected with an output end of the signal processing circuit and is used for sampling the voltage pulse signal and converting the voltage pulse signal into a digital signal;
the first processor and the second processor are connected with the signal processing circuit through the signal acquisition circuit;
The signal acquisition circuit is an analog-to-digital conversion circuit.
3. The particle counter with early warning function according to claim 1, wherein the signal processing circuit includes an amplifying circuit for amplifying the photocurrent signal;
The signal processing circuit further comprises a filter circuit.
4. The particle counter with early warning function according to claim 2, wherein the first processor performs statistics and calculation on the digital signal collected by the signal collection circuit to obtain a concentration of particles of the gas to be measured.
5. A method for determining an operation mode of a particle counter according to any one of claims 1 to 4, comprising:
Step 1, receiving gas particles to be detected;
step 2, monitoring the concentration of the gas particles to be detected and obtaining concentration data of the gas particles to be detected;
And step 3, comparing the gas particle concentration data to be detected with a preset early warning concentration, counting the gas particles to be detected by a particle counter and obtaining counting data based on the fact that the gas particle concentration data to be detected is lower than the preset early warning concentration, or taking early warning measures based on the fact that the gas particle concentration data to be detected is higher than the preset early warning concentration.
6. The method for determining the working mode of the particle counter according to claim 5, wherein the step 1 comprises the steps that the gas circuit system of the particle counter obtains the gas particles to be detected and transmits the gas particles to the scattered light collecting system, the photoelectric detector receives scattered light of the gas particles to be detected and converts the scattered light into a photoelectric current signal and transmits the photoelectric current signal to the signal processing circuit, and the signal processing circuit converts the photoelectric current signal into a voltage pulse signal;
The first processor of the particle counter carries on the concentration measurement to the said gas particle to be measured according to the said voltage pulse signal, and obtain the concentration data of the said gas particle to be measured;
The step 3 includes that based on a comparison result of the gas particle concentration data to be detected and preset early warning concentration data, when the gas particle concentration to be detected is smaller than the preset early warning concentration, the particle counter continues to count particles, and when the gas particle concentration to be detected is not smaller than the preset early warning concentration, the input of the gas particles to be detected into an air inlet channel of the particle counter is stopped.
7. The method according to claim 6, wherein the second processor of the particle counter counts the number of particles of the gas particles to be measured according to the voltage pulse signal in step 2 and/or step 3.
8. The method according to claim 7, wherein the second processor counts the particles when the concentration of the particles of the gas is less than the predetermined pre-warning concentration, and stops the particle counting when the concentration of the particles of the gas is not less than the predetermined pre-warning concentration, or continues the counting, and the obtained count is used as the invalid data.
9. The method according to claim 6, further comprising step 4 of cleaning a measurement cavity of the particle counter by supplying clean gas to the gas path system after stopping supplying the gas particles to be measured to the gas path system until the measurement cavity meets a preset standard measurement condition.
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| CN114486688B (en) * | 2022-01-28 | 2024-12-24 | 苏州苏信环境科技有限公司 | Particle counter measurement method, device, equipment and storage medium |
| CN114544441B (en) * | 2022-02-28 | 2024-11-29 | 苏州苏信环境科技有限公司 | Self-checking method, system, device and medium for particle counter |
| CN114791410A (en) * | 2022-04-27 | 2022-07-26 | 苏州苏信环境科技有限公司 | Method, system, device and medium for calibrating output signal of particle counter |
| CN117169092B (en) * | 2023-09-01 | 2024-08-13 | 深圳市宏大联合实业有限公司 | Photoelectric sensor based on small-flow dust particle counter and counting method thereof |
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