This standard specifies the structure, technical requirements, test methods, inspection rules and marking, packaging, transportation and storage of ammonia gas detection tubes. This standard applies to long-length ammonia gas detection tubes (hereinafter referred to as detection tubes). MT 273-1994 Ammonia gas detection tube MT273-1994 Standard download decompression password: www.bzxz.net

Coal Industry Standard of the People's Republic of China
Subject content and scope of application
MT273-94
This standard specifies the structure, technical requirements, test methods, inspection rules and marking, packaging, transportation and storage of ammonia detection tubes. This standard applies to long-length nitrogen detection tubes (hereinafter referred to as detection tubes). 2 Reference standards
GB7230 Gas detection tube device
GB10111 Method for random sampling using random number generators 3 Structure
3.1 The structure of the detection tube is shown in Figure 1:
Figure 1 Schematic diagram of ammonia detection tube
1—Tube tip, 2—Starting plug; 3-Isolation layer: 4-Indicator powder ±5 Glass tube: 6—Liner plug 3.2 The measurement range of the detection tube is 20~200ppm, and the minimum graduation value is 20ppm. 4 Technical requirements
4.1 The interfaces of each layer of the detection tube filling should be neat. 4.2 The graduation lines of the test tube should be clear and firm. The length difference of each box of test tubes should not exceed 5mm. 4.3
The distance between the lining plug at the starting end of the test tube and the tip of the tube should not be less than 5mm44
4.5 The difference between the longest and shortest ends of the interface between the isolation layer and the indicator powder along the longitudinal direction of the tube wall should not exceed 1mm. 4.6 After the test, the difference between the longest and shortest ends of the interface between the discolored part and the undiscolored part of the indicator powder along the longitudinal direction of the tube wall should not exceed 20% of the average value of the two.
4.7 After the drop test, the filling of the test tube should be tight, and there should be no gap between the plug and the isolation layer. 4.8 The minimum detection concentration of the test tube is 20ppm. 4.9 The precision (CV,) of the test tube is less than or equal to 10%. 4.10 The accuracy of the test tube at room temperature should meet the requirements of Table 1. Approved by the Ministry of Energy of the People's Republic of China on May 1, 1992 156
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Implementation on October 1, 1994
Detection range, ppm
>80～200
4.11 The validity period of the test tube shall be no less than 1 year. MT 273-94
Relative error of the measured value
4.12 The test tube must be used in conjunction with a special sampler that meets the requirements of Article 3.2 of GB7230. 5 Test method
5.14.1 and 4.2 shall be checked by sensory organs.
5.24.3~4.6 shall be measured with a steel ruler with a graduation value of 0.5mm. 5.3 Drop test
Average relative error of measured valuesbZxz.net
Ten test tubes are randomly selected from the sample for drop test. During the test, the starting end of the test tubes is bundled downward, and they are freely dropped from a height of 25mm to a 5mm thick rubber plate 10 times, and then the internal filling is checked. 5.4 Minimum detection concentration test
Ten test tubes are randomly selected from the sample, and a standard gas sample with a concentration of 20±2Ppm is used. At room temperature, the test is carried out according to the method specified in the instruction manual to check whether the color change is obvious. The uncertainty of the standard gas sample is ±3% (the same below). 5.5 Precision and accuracy test
Twenty test tubes are randomly selected from the sample, and the standard gas samples specified in Table 2 are used. At room temperature, the test is repeated 10 times for each concentration of standard gas sample according to the method specified in the instruction manual. The measured value of the detection tube is calculated according to formula (1):
Wherein: X——the measured value of the detection tube, ppm, L—the measured value of the color change length of the indicator powder, mm, Lc.
The concentration of the detection tube close to the graduation line of the standard gas sample concentration, PPm; C.
L. The length from the starting end of the graduation line of the detection tube to the graduation line close to the standard gas sample concentration, mm. The precision of the detection tube is calculated according to formula (2):
c. V. (%) =
Wherein: α—standard deviation,
X-the average value of the measured value of the detection tube, ppm. The accuracy of the test tube is calculated according to formula (3) and formula (4): A,
Subtract
(3)
Where: A——Relative error of the measured value, %; MT 273 -- 94
—Relative error of the average value of the measured value, %
XMeasurement value of the test tube, ppm
X—Average value of the measurement value of the test tube, ppm, SStandard gas sample concentration, ppm.
Test range
>80200
5.6Test data processing
5.6.1When calculating the measurement value of the test tube, the significant figures are retained to 1 decimal place. Standard gas sample concentration
140±5
5.6.2When calculating the precision and accuracy of the test tube, calculate to two decimal places and round to 1 decimal place. 6 Inspection rules
Products are divided into factory inspection and type inspection.
6.1 Factory inspection
6.1.1 Products shall be inspected by the factory quality inspection department. They can only be shipped after passing the inspection and issuing a certificate of conformity. 6.1.2 Each batch of products shipped shall be subject to factory inspection. Factory inspection items include 4.1 to 4.10. 6.2 Type inspection
6.2.1 Type inspection shall be carried out in any of the following situations: when new products are being tested for trial production and when old products are transferred to the factory for production; b
After formal production, if there are major changes in structure, materials, and processes that may affect product performance; during normal production, an inspection shall be carried out once a year. After one year of suspension of production, when production is resumed
When the factory inspection results are significantly different from the last type inspection; when the national quality supervision agency proposes a request for type inspection. 6.2.2 Type inspection items include 4.1 to 4.10. 6.3 Sampling
6.3.1 Factory inspection sampling
150 tubes shall be sampled from the same batch of products packed in boxes ready for shipment according to the method specified in GB10111. 6.3.2 Type inspection sampling
150 tubes shall be sampled from the products that have passed the factory inspection according to the method specified in GB10111. Pprm
6.3.3 Randomly select 3 boxes from the sample for the test in 4.3, then randomly select 10 tubes from each box after mixing the test tubes for the tests in 4.14.2, 4.4, and 4.5; randomly select 10 tubes for the test in 4.7, and randomly select 10 tubes for the test in 4.8; randomly select 20 tubes for the tests in 4.9 and 4.10: then use the test tubes used for the higher concentration accuracy test to conduct the test in 4.6. 6.4 Determination rules
6.4.1 For 4.3, if 2 boxes do not meet the requirements, it is determined to be unqualified. 6.4.2 For 4.1, 4.2, 4.4.4.5, if 3 test tubes do not meet the requirements, it is determined to be unqualified. 158
Note
MT 273 - 94
6.4.3 For 4.6.4.7, if 2 test tubes do not meet the requirements, it is determined to be unqualified. 6.4.4 For 4.8, if 2 test tubes do not meet the requirements, it is determined to be unqualified: if 1 test tube does not meet the requirements, the number should be doubled for re-inspection. If it still does not meet the requirements, it is determined to be unqualified. 6.4.5 For 4.9, if it does not meet the requirements, it is determined to be unqualified. 6.4.6 For Article 4.10, if both items fail to meet the requirements, it shall be immediately judged as unqualified. If one item fails to meet the requirements, the quantity shall be doubled for re-inspection. If it still fails to meet the requirements, it shall be immediately judged as unqualified. 7 Marking, packaging, transportation, storage
7.1 Marking
7.1.1 Product marking
The marking on each test tube shall include
the measuring instrument mark;
b, trademark
batch number.
7.1.2 Packaging Marks
The markings on the packaging box of the test tube should include: a.
Manufacturer's name,
Product name and model:
Quantity;
Trademark;
Batch number,
Expiration date,
Manufacturing measuring instrument license number
Instrument inspection certificate number:
Safety mark and its number.
The packaging box should have "fragile" and "handle with care" signs. 7.2 Packaging
The test tubes are packed in a hard box according to a certain quantity and fixed with soft objects. They should not be moved. The box should be accompanied by the instruction manual and product certificate.
7.3 Transportation
Avoid dropping or smashing during shipment and ship as fragile items. 7.4 Storage
The test tube should be stored in a dry room at room temperature and avoid sunlight. Additional remarks:
This standard was proposed by China Coal Research Institute. This standard is under the jurisdiction of Fushun Branch of China Coal Research Institute. This standard was jointly drafted by Fushun Branch of China Coal Research Institute and Hebi Mining Bureau. The main drafters of this standard are Yang Wenzheng, Chen Xingye and Ye Zhanying. This standard is entrusted to Fushun Branch of China Coal Research Institute for interpretation. 159
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