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The National Metrology Verification Regulation of the People's Republic of China JJG956-2000
Air Sampler
AirSampler
2000-09-22 Issued
2000-12-22 Implementation
National Quality and Technical Supervision Bureau Issued
JJG956-2000
Yerification Regulation
for Air Sampler Sampler
JJG956—2000
This regulation was approved by the State Quality and Technical Supervision Administration on September 22, 2000, and came into effect on December 22, 2000.
Responsible unit: National Technical Committee for Environmental Chemical Metrology Main drafting unit: National Standard Material Research Center Participating drafting unit: National Standard Material Research Center This regulation is entrusted to the National Technical Committee for Environmental Chemical Metrology for interpretation. Main drafters of the regulation:
Li Changkai
Chen Yonghua
Participating drafters:
Zhang Guoxian
JIG956
(National Standard Material Research Center)
(National Standard Material Research Center)
(National Standard Material Research Center)| |tt||Meter performance requirements:
Small error of the plate
Flow repeatability
Flow stability
Time error
Temperature control stability
General technical requirements
Gauge inspection
Safety inspection
Measuring instrument production
Requirements for inspection environment·
Specified equipmentwwW.bzxz.Net
Inspection items·…
Inspection method
Processing of inspection results and inspection synchronization
Processing of inspection results
Inspection period
Format of the inner page of the inspection certificate
Format of the inner page of the inspection result notice
Format of inspection record
JJG9562000
1 Scope
5G 9562000
Atmospheric Sampler Verification Procedure
This procedure is applicable to the initial verification, post-verification and inspection of ordinary type constant temperature and constant flow type atmospheric samplers (hereinafter referred to as samplers).
2 Overview
The principle of atmospheric samplers is to extract samples through the sampling system, adopt different flow stabilization measures and synchronous timing methods to achieve the purpose of collecting atmospheric gas or gas samples, and analyze the harmful components: samplers are divided into two categories: ordinary type and constant temperature and constant flow type: ordinary type samplers are composed of adjustable flow meter, timing controller, sampling system and power supply, which are used for continuous sampling; constant temperature and constant flow type samplers are composed of single chip microcomputer, constant temperature and constant flow controller, sampling system and power supply, which can realize continuous sampling under constant temperature and constant flow. 3 Measurement performance requirements
3.1 The error of flow indication should not exceed ±5% of the flow indication.
3.2 Flow rate repeatability
Flow rate repeatability should not be less than 2%.
3.3 Flow rate stability
For general use, the sampling flow rate should not change by more than 5% within 1 hour and within 8 hours of constant temperature and constant type operation. 3.4 Time error
The time difference should not exceed ±0.2%.
3.5 Temperature control stability
The temperature control stability of the test flow type sampler should not be greater than 24. General technical requirements
4.1 Routine inspection: Whether
41, the instrument system is complete, the connection is reliable, all buttons can be properly adjusted, and there should be no external damage to the instrument that affects the normal operation of the sampler.
4.1.2 The display part should be clear and small.
4.1.3 The airtight performance of the sampling system must be good.
4.1.4 The name, model, year and month of manufacture, group number, manufacturing measuring instrument license mark and manufacturer's name should be complete and clear.
4.2 Safety inspection
Insulation resistance: The insulation resistance of the device should be 20M0:1
5 Measuring instrument control
J.IG956-2000
Measuring instrument control includes piece determination, subsequent verification and in-use inspection. 5.1 Verification environment requirements
5.1.1 Ambient temperature 15~35℃,
5.1.2 Ambient humidity 85%RH,
5.1.3 Power supply voltage 1k7-242V, 49--51Hz. 5.2 Replacement equipment
5.2.1 Mould flow meter: Use volume 50-200mL, allowable error is not more than 1%. 5.2.2 Thermometer: 0-50, scale value not greater than 0.2℃, indication error not greater than ±0.5℃. 5.2.3 Seconds; resolution not greater than 1.1 sc
Gas meter: measuring range 8·-105kl'a: allowable error ±100Pa, 5.2.5 Insulation resistance meter: 10 level (500V). 5.2.6 Gas pipeline, needle valve, etc.
5.3 Verification items
Verification items are shown in Table 1.
Verification items
Flow indication error
Flow stability
Design error
Control product quality
Present
Safety inspection
First verification
“+“ must be determined
After verification
It is an important inspection item
After the verification, it will have a great impact on the quality performance, so it must be carried out in accordance with the safety regulations. 5.4 Control method
5.4.1 Routine inspection
JIG 956—20CH
According to the requirements of 4.1.1.-1.1.1. Use the following method to check the air tightness of the system: Under this operating state, the system population is airtight: the flow rate should gradually drop to zero. : 5.4.2 Safety inspection
Insulation resistance inspection, only the device is in the non-operating state, the switch is connected to the inspection stomach, the wiring terminals of the insulation resistance are respectively connected to the energy and machine light of the set point source, and a DC test voltage of 5V is applied. After stabilization, the absolute resistance value indicated by the insulation meter is measured: 5.4.3 Verification of flow indication error
5,4.3.1 For ordinary type flow meter, the flow rate values at the upper, middle and lower points are: For high temperature flow type, only the constant flow point is calibrated,
5.4.3.2, the flow rate is measured by the membrane flowmeter, the method is as follows, the person under test moves to the outlet of the membrane flowmeter, after the instrument is stable, adjust the sample flow rate to the calibration point, measure the time between the gas passing through the membrane base and the specified part, and record the air pressure and temperature of the experimental environment at the same time, calculate the actual Q (ml/min) measured by the membrane flowmeter
Q - (V/) × 60
Where: Q is the actual flow, ml./min;
is the volume of the membrane flowmeter, mL;
is the time for the gas to pass through the membrane flowmeter. The flow rate converted to the standard state is: Qs - Q × Is ×
Where: 2-flow rate under standard conditions; P-air pressure in the calibration environment, kP;
Ps× T
P is the water and steam pressure corresponding to the calibration temperature, kP-; P-air pressure under standard conditions, 101.3Pa; - -scientific temperature in the calibration environment, K; T is the thermodynamic temperature under standard conditions, 23.15K, (1)
5.1.3.3 Mark each point 3 times, collect the arithmetic mean of the 3 times, and calculate the indication error of the calibration point according to formula (3). Take the indication error of the calibration point as 101%
QQsx101%
Formula: -- calibration point value:
Q-calibration point flow rate:
J.IK 956---2000
One calibration point standard flow product arithmetic average value -5.4.4 Flow repeatability calibration
5.4.4.1. For ordinary samplers, select the middle scale flow; for constant temperature and constant flow samplers, select the constant flow point; and measure the selected point 6 times.
5.4.4.2 Use the same method as in 5.4.3.2 to obtain the time for the gas to pass through the film flow meter with a fixed volume V, and calculate the flow rate according to formula (4):
2(Q, - 0.)2
s-1
Where:
——arithmetic mean of the measurements;
n——number of measurements;
t——the time for the gas to pass through the film flow meter with a fixed volume in the first measurement;
t——the time for the gas to pass through the film flow meter with a fixed volume in each measurement, s5.4.5 Verification of flow rate
Continue with 5.4.3.1 to select the verification point. After the instrument is stable, perform the verification according to 5.4.3.2. The measurement method is to measure the time for the gas to be tested to pass through the fixed part of the soap film flowmeter. Without adjusting the sampling flow, the ordinary sampler works continuously for 1 hour, and the measurement is made once every 20 minutes, for a total of 4 times; the constant temperature flow sampler works continuously for 8 hours, and the measurement is made once every 2 hours, for a total of 5 times. Take the maximum and minimum values of the series and use formula (5) to calculate the maximum change of time: that is, the stability with the amount.
- Qmgm×100% - Tem ag ×100%Q
In the formula:
The arithmetic mean of the measurement;
The average value of the time measurement;
The maximum value of the time measurement;
The minimum value of the time measurement.
5.4.6 The time difference is determined by
and compared with a qualified stopwatch. Set the sampling time of the sampler to 1, start the stopwatch and the sampling solution at the same time, and when the sampler reaches the set time, stop the timing, record the stopwatch time, and use formula (6) to calculate the timing error.
. - 1- 2× 100%
Where:
Sampler timing time:
Stopwatch evaluation time.
5.4.7 Verification of control stability
JJC456—2000
For temperature flow samplers. Connect the thermometer to the sampler, and start recording the first value T after it stabilizes. Continuously measure for 8 hours, and take the maximum value T. and minimum value Ti of each measurement moment, and calculate the temperature control stability according to formula (?).
AI= 6. Handling of verification results and verification period. Handling of verification results: For the qualified samplers, a verification certificate will be issued; for the samplers that fail the verification, a verification result notice will be issued, and the unqualified items will be indicated. 2. Verification period: The verification period of atmospheric samplers is usually no more than one year: Appendix A: Verification items: 1. Setting difference of the indication value:
2 Urine flow repeatability:
3 Flow stability:
Timing error:
Overflow stability:
Gauge inspection:
Safety inspection:
Conclusion: Qualified
The following is blank
956-004
Inner page format of calibration certificate
Technical requirements
Calibration results
Appendix B
Calibration items||t t||Flow indication error:
Drip containment resilience:
Flow stability:
Timing error:
Temperature control stability:
Belt gauge inspection:
Safety inspection:
The following is blank
JJG956—2000
Inner page format of the verification result notice
Technical requirements
Verification results
Single item results
Appendix C
Date:
Temperature:
Instrument name:
Inspection unit:
Release basis:
Verification standards and devices:
Measurement uncertainty:
Verifier:
Routine inspection
Flow indication error
Flow indication
III. Mother change complex
Condensation degree:
Time, (s)
JJG 95G—2000
Verification record format
Model:
Inclusion factor:
Verifier:
Indication value (:nnin
k'aI'v:
No.:
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