This standard specifies the basic technical requirements and measurement methods for optical interferometer methane detector calibrators. This standard applies to liquid pressure gauge calibrators and electronic pressure gauge calibrators (hereinafter referred to as calibrators). MT 424-1995 General Technical Requirements for Optical Interferometer Methane Detector Calibrators MT424-1995 Standard download decompression password: www.bzxz.net

Coal Industry Standard of the People's Republic of China
Optical Interference Methane Determination Calibrator
General Technical Conditions
1 Subject Content and Scope of Application
This standard specifies the basic technical requirements and measurement methods for the optical interference methane determination calibrator. MT 424—1995
This standard applies to liquid pressure gauge calibrators and electronic pressure gauge calibrators (hereinafter referred to as calibrators). 2 Basic Technical Requirements
2.1 General Requirements
2.1.1 The normal working environment temperature of the calibrator is 15~35℃. 2.1.2 There should be no obvious dents, scratches and deformation on the surface of the calibrator, and the spray coating should be uniform, firm and consistent in color. 2.1.3 The fasteners of the calibrator should be guaranteed to be tight and reliable. 2.1.4 The graduation or display of the calibrator should be clear. 2.1.5 The operation of the calibrator should be flexible and reliable, and there should be no sticking, loosening or jumping. The pressure regulator should be able to easily adjust the pressure to any calibration point.
2.2 Basic error of indication and minimum scale value
The pressure range corresponding to the calibration of different measuring sections of the optical interference methane detector and the corresponding calibrator indication range, basic error limit and minimum scale value should comply with the provisions of Table 1 and Table 2. Table 1 Calibration of the methane measuring instrument with the upper limit of measurement not exceeding 10% CH4 Methane concentration, % (V/V)
Calibration range
Pressure, Pa
Calibrator indication range, Pa
Calibrator basic error, Pa
Calibrator minimum graduation value, Pa
0~～520
0～600
>1～4
>520~2100
0～2100
>2 100~3 700
0～3700
Table 2 Calibration of methane measuring instruments with upper limit greater than 10%CH4 Methane concentration, %(V/V)
Calibration range
Pressure, kPa
Calibrator indication range, kPa
Calibrator basic error, Pa
Calibrator minimum scale division, Pa
>10～40
>5. 2～~21
>40～70
>21～37
>7～10
>3 700~5 200
0～6000
>70～100
>37～52
0～60
Note: The calibrator can be divided into two types according to its structure: single-limit and multi-limit. When a certain range of the calibrator is used to calibrate two or more measuring sections of the optical interference methane detector, the upper limit of its range shall not be less than the maximum value of the calibrator indication corresponding to the calibrated measuring section, and the allowable basic error shall not exceed the minimum value of the calibrator basic error corresponding to the calibrated measuring section. 2.3 Airtightness requirements
During the airtightness test of the calibrator, its indication shall not drop. 2.4 Other technical requirements
The calibrator shall also comply with other relevant standards for its various products. 3 Determination method
3.12.1.2~2.1.5 shall adopt sensory inspection. 3.2 Basic error determination
3.2.1 Determination conditions
The ambient temperature is 20±5℃.
3.2.2 Standard instrument
The absolute value of the allowable error of the standard pressure gauge is less than or equal to 1/2.5 of the absolute value of the allowable basic error of the calibrator under inspection. 3.2.3 Measuring points
No less than 4 evenly distributed measuring points shall be selected for the calibrator. For the calibrator of the methane measuring instrument with a measurement upper limit not exceeding 10%CH4, a point of 520Pa shall be included; for the calibrator of the methane measuring instrument with a measurement upper limit exceeding 10%CH4, a point of 5.2kPa shall be included. 3.2.4 Determination steps
3.2.4.1 Determination shall be carried out by comparison with the standard pressure gauge. Connect the calibrator, the standard pressure gauge and the pressure regulator to the tee with a hose (as shown in Figure 1). First check the air tightness, and then re-measure after it meets the requirements. 3.2.4.2 During the measurement, the load should be increased steadily from zero, passing through the specified measuring points to the upper limit of the measurement, and then the load should be reduced steadily to zero, and then passing through the above measuring points.
3.2.4.3 Carry out three stroke measurements according to the steps in 3.2.4.2. 3.2.4.4 The average value of the difference between the standard pressure gauge reading and the calibrator reading is taken as the basic error. Atmosphere
Figure 1 Measurement system diagramwwW.bzxz.Net
1-Tee; 2-Pressure regulator; 3-Standard pressure gauge? 4-Calibrator 3.3 Air tightness test
Apply the upper limit pressure to each measurement range of the calibrator measurement system for 3 minutes and observe whether the pressure drops. 244
Additional instructions:
MT424-1995
This standard is proposed by the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the jurisdiction of the Coal Mine Gas Detection and Rescue Equipment Branch of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard was drafted by the Fushun Branch of the China Coal Research Institute. The main drafter of this standard is Yin Fangxiong.
This standard is interpreted by the Fushun Branch of the China Coal Research Institute. 245
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