GB/T 6167-2026Test methods for the performance of airborne particle counters (English PDF)

4.3 Particle size parameters

4.3.1 Particle size setting error The particle size setting error of the particle counter should not exceed ±10%.

4.3.2 Particle size resolution The particle size resolution of the particle counter should not exceed 15%.

4.3.3 Particle size distribution error When using 0.4 µm standard particles, the particle size distribution error of the particle counter should not exceed 15%; when using 0.6 µm standard particles... At that time, the particle size distribution error of the particle counter should not exceed -30%.

4.4 Counting efficiency When using standard particles at the corresponding minimum particle size setting, the counting efficiency of the particle counter should be (50±20)%; when using the corresponding When using standard particles at

1.5 to 2 times the minimum particle size setting, the counting efficiency of the particle counter should be (100 ± 10)%.

4.5 Pseudo-counting The particle counter continuously samples air samples that do not contain particles within the instrument's measurement range, considering the upper limit of the 95% confidence probability of the Poisson distribution. The value should not exceed 1 grain/5 min.

4.6 Counting Response Capability When switching from sampling high-particle-number-concentration gas to clean gas, the counting response capability of the particle counter should not exceed 0.5%.

4.7 Upper limit of particle number concentration The upper limit of particle number concentration of a particle counter should not be lower than 90% of the nominal value.

5.2 Test Materials and Instruments

5.2.1 The test materials shall conform to the requirements of Table 2.

5.2.2 The testing instruments shall comply with the following provisions.

a) Electronic stopwatch. 0.01s graduation value, maximum permissible error of ±0.1s per hour.

b) Gas flow meter. The range covers the sampling flow rate of the test particle counter, with a maximum permissible error of ±2%.

c) Pulse height analyzer. sampling frequency not less than 10MHz, indicated voltage range covering 0V~10V, maximum permissible indicated voltage Error ±0.2%, sampling channels no less than 256.

d) Reference particle counter. Compared with condensation nucleus particle counters or higher-performance instruments, the counting efficiency meets the requirements of 4.4; When used for particle number concentration upper limit tests, the particle number concentration upper limit shall not be lower than the particle number concentration of the test particle counter.

1.5 times the limit.

e) Reference condensed nucleus particle counter. the counting efficiency is calibrated and does not exceed (100±10)%.

5.3 Sampling Time

5.3.1 Power on and warm up. After the particle counter enters normal working condition, set the sampling time to 5 minutes.

5.3.2 Simultaneously start the electronic stopwatch and particle counter. When the particle counter reaches the set sampling time, stop timing and record the stopwatch's lowest value. The time (t) is then displayed.

5.3.3 The sampling time error is calculated according to formula (1).

5.4 Sampling flow rate

5.4.1 Connect the gas flow meter to the sampling inlet of the particle counter. The length of the connecting pipe should not exceed 0.3m.

5.4.2 After powering on and preheating, once the particle counter is in normal working condition, begin sampling and read three flow measurement values, taking the average value. The first set of flow measurement results was used to run the system for

0.5 hours. Afterward, the flow was measured three more times using the same method, and the average value was taken as the second set of flow measurement results. The relative deviation between the two sets of measurement results should not exceed ±5%.

5.4.3 The relative error of the sampling flow rate is calculated according to formula (2).

5.5.1 Voltage Setting

5.5.1.1 A relationship between the electrical pulse height and particle size should be established using standard particles to determine the response of each particle size setting on the particle counter. The voltage should be considered; when the particle counter introduces different amplification factors for different particle size settings in the circuit analysis system, it should be processed in segments.

5.5.1.2 Select standard particles corresponding to each particle size setting of the particle counter. Prepare dilution solutions according to the requirements of Appendix B, and follow the procedures outlined in Appendix C. The specified test apparatus shall generate monodisperse aerosols, and the particle number concentration shall not exceed the upper limit of the particle number concentration of the particle counter. 25%.

5.5.1.3 After powering on and preheating, once the particle counter is in normal working condition, connect its sampling inlet to the sampling tube of the test device and input the pulse... The height analyzer is connected to the pulse signal output of the particle counter.

5.5.1.4 Start sampling, analyze no less than 1000 electrical pulse signals, and plot the pulse height distribution curve.

5.5.1.5 Based on the pulse height distribution curve, determine the response voltage of standard particles of different sizes according to the following method.

5.5.2 Particle size setting error

5.5.2.1 Select the particle size setting and conduct a particle counter particle size setting error test.

5.5.2.2 Use at least three different standard particles close to the selected particle size range, with particle size ranges covering the selected particle size range and corresponding to it. Using the same amplification factor, the corresponding response voltage was measured according to the method specified in

5.5.1 to obtain the actual response voltage versus particle size relationship. The curve should be fitted using a method provided by the instrument manufacturer, and the correlation coefficient of the curve fitting should not be lower than 0.9.

5.5.2.3 For the selected particle size range, the manufacturer provides the threshold voltage setting (Vt). Based on the actual response curve, calculate the threshold voltage setting (Vt). The corresponding actual particle size value (x'). Calculate the particle size setting error according to formula (3).

5.5.3 Particle size resolution

5.5.3.1 Select the particle size setting and conduct a particle size resolution test on the particle counter.

5.5.3.2 For the selected particle size range, select the corresponding standard particle and denote its particle size as xsigma. Measure the electrical pulse according to the method specified in 5.5.1. The peak voltage (Vl, sigma) and upper limit voltage (Vu, sigma) corresponding to a particle percentage of 61% were determined based on the impact height distribution, as shown in Figure 3; according to The actual response curve covering xsigma is obtained by the method specified in 5.5.2, and the particle sizes (xl,sigma and xu,sigma) corresponding to Vl,sigma and Vu,sigma are determined.

5.5.4 Particle size distribution error

5.5.4.1 For the 0.5µm particle size range, particle size distribution error tests should be conducted using both 0.4µm and 0.6µm standard particles. For other particle size settings, the instrument manufacturer or user can select standard particles and conduct the test according to this method.

5.5.4.2 When using 0.4µm standard particles, the test shall be conducted according to the following steps.

a) Prepare the diluent according to the requirements of Appendix B, and generate monodisperse aerosols according to the test apparatus specified in Appendix C, with the number of particles... The concentration should not exceed 25% of the upper limit of the particle number concentration of the particle counter.

b) After powering on and preheating, once the particle counter is in normal working order, connect its sampling inlet to the sampling tube of the test device to begin sampling. Sample; after 5 minutes of normal operation, begin measuring particle number concentration (>=0.3µm, >=0.5µm), taking 5 consecutive samples, each time... The sampling time is 1 minute.

c) Calculate the particle size distribution (h0.5,ji) according to formula (6), calculate the average particle size distribution (h0.5,j) according to formula (7), and calculate the particle size distribution (h0.5,j) according to formula (8). Path distribution error (Deltah0.5,j).

5.7.1 Connect the self-cleaning filter that meets the requirements of

5.2.1 to the sampling inlet of the particle counter under test, turn on the machine to preheat, and wait for the particle counter to... After entering normal working state, run for 5 minutes.

5.7.2 Restart sampling and run continuously for 15 minutes. A reading of 0 for the minimum particle size setting of the tested instrument is acceptable. A non-zero reading indicates otherwise. The counts are considered pseudo-counts. The analysis of pseudo-count results uses a Poisson distribution, with the upper limit of the 95% confidence probability as the criterion. A 15-minute timeframe is used for the analysis. When the number of particles is 0, the upper limit of its 95% confidence probability is 3 particles, which corresponds to a result of no more than 1 particle/5min.

5.8 Counting Response Capability

5.8.1 For standard particles used with a particle counter minimum particle size setting of

1.5 to 2 times, the dilution solution should be prepared according to the requirements of Appendix B, and should be prepared in accordance with... For the test apparatus specified in Appendix C, the particle number concentration of monodisperse aerosols generated should be at the upper limit of the particle number concentration of the instrument under test. (90±10)%.

5.8.2 After powering on and preheating, once the particle counter is in normal working order, connect its sampling inlet to the sampling tube of the test device to begin sampling. Sample; after 5 minutes of sampling, continue sampling for 1 minute and record the particle number concentration at the smallest particle size setting of the tested instrument during this period.

5.8.3 Immediately connect the self-cleaning filter that meets the requirements of

5.2.1 to the sampling inlet of the particle counter. After sampling for 10 seconds, continue sampling. Record the particle number concentration at the smallest particle size setting of the tested instrument for 1 minute.

5.8.4 The counting response capability is calculated according to formula (10).

5.9 Upper limit of particle number concentration

5.9.1 Use the upper limit of nominal particle number concentration as the preset value in the test. The upper limit of nominal particle number concentration can be provided in the product instructions. The result can also be obtained by formula (11).

5.9.2 When using standard particles at

1.5 to 2 times the minimum particle size setting of the test particle counter, the dilution solution should be prepared according to the requirements of Appendix B, and When generating monodisperse aerosols using the test apparatus specified in Appendix C, the particle number concentration should be close to that of the instrument under test. Limited to preset values.

5.9.3 Turn on the test particle counter and reference instrument and preheat them until they are in normal working condition, then connect their sampling inlet to the test apparatus. The particles were sampled and counted simultaneously on different sampling tubes, and the particle number concentration results (C1,1, C0,1) of the minimum particle size setting of the two instruments were recorded respectively.

5.9.4 Adjust the experimental setup to dilute the test aerosol until the particle number concentration (C0,2) measured by the reference instrument decreases to the original particle number concentration C0,1. The particle number concentration of the tested instrument was recorded at (50±5)%, and the result was recorded as (C1,2).

5.9.5 If C1,2 is higher than 60% of C1,1, it indicates that the preset upper limit of particle number concentration determined in

5.9.1 is too high. The preset value should be reduced by 10%. Set a value and repeat the test steps

5.9.4 until C1,2 is (50±10)% of C1,

1.The preset value at this point is the number of particles in the tested instrument. The upper limit of particle number concentration; if C1,2 is not higher than 60% of C1,1, it means that the preset value of the upper limit of particle number concentration determined in

5.9.1 is not higher than the actual value. The value is increased by 10%, and the experimental steps

5.9.4 are repeated until C1,2 exceeds C1,1 by 60%. The previous set of experimental values is used to determine the optimal value. The value is set as the upper limit of particle number concentration of the instrument under test.

5.9.6 For other particle size settings specified by the user, the corresponding upper limit of particle number concentration can be determined by referring to the above method. In the experiment, using... The standard particles corresponding to this particle size setting are used to measure the particle number concentration of the tested instrument and the reference instrument at this particle size setting.

5.10 Comparative Test When the standard test conditions are not available, polydisperse aerosols in the ambient air can be used, and the comparative method in Appendix D can be employed for testing. Compare the consistency of the values displayed by the test instrument and the reference instrument.