This standard specifies the technical requirements, inspection methods, inspection rules for pure helium products, as well as product packaging, marking, storage, transportation, etc. This standard applies to bottled gaseous helium extracted from air, natural gas or factory exhaust gas by cryogenic method. It is mainly used for welding, diving breathing, special metal smelting, chromatographic analysis carrier gas, as well as pressurization and cleaning gas. GB 4844.2-1995 Pure helium GB4844.2-1995 standard download and decompression password: www.bzxz.net

National Standard of the People's Republic of China
Pure
Hydrogen
Pure helium
Subject content and scope of application
GB4844.2—1995
Replaced GB4844~4845·84
This standard specifies the technical requirements, inspection methods, inspection rules for pure nitrogen products, as well as product packaging, marking, storage, transportation, etc. This standard applies to bottled gaseous ammonia extracted from air, natural gas or factory exhaust gas by cryogenic method. It is mainly used for welding, diving breathing, special metal smelting, chromatographic analysis carrier gas, as well as pressurization and cleaning gas. Molecular formula: He
Relative molecular mass: 4.00260 (according to the 1991 international relative atomic mass). Reference standards
2
GB/T4844.1 Industrial hydrogen
GB/T4844.3 High purity nitrogen
GB/T5832.1 Determination of trace moisture in gas electrolysis Method GB/T8984 Determination of carbon monoxide, carbon dioxide and methane in gases Gas Chromatography 3 Technical requirements
The quality of pure nitrogen products should meet the requirements of Table 1. In the table, "Purity" and "Content" are both volume fractions (V/V). Table 1
Technical indicators
Item
Nitrogen purity, 10~2
Chlorine content, 106
Hydrogen content, 106
Oxygen (argon) content, 10
Nitrogen content, 106
Oxide carbon content, 106| |tt||Carbon dioxide content, 10-6
Methane content, 106
Moisture content, 106
4 test methods
4.1 Hydrogen*Purity||tt ||National Technical Supervision Bureau approved high-quality products on December 20, 1995
99.995
15
3
3
10
1
1
1
10
refers to
standard
first-class product
99.993
25
5
s
17
1
1
15
Qualified productWww.bzxZ.net
99.99| |tt||40
: 5
25
20
1996-08-01 Implementation
723
GB 4844.2-1995
Hydrogen purity is expressed in volume fraction, calculated according to the following formula: = 100(Φ +++Φ+Φ++,+)×10-a where: Φ——Purity, 10-2(V/ V);
Φ - chlorine content (volume fraction), 10-6V/V) Φ2 - hydrogen content (volume fraction), 10-6 (V/V) @ - oxygen (argon) content ( Volume fraction), 10-6 (V/V); @----Nitrogen content (volume fraction), 10-6 (V/V); s—. Carbon monoxide content (volume fraction), 10-(V/V ); @ - carbon dioxide content (volume fraction) 10-6 (V/V); @, - methane content (volume fraction), 10-\ (V/V); Φg - moisture content (volume fraction), 10 - (V/V). 4.2 Determination of atmosphere, hydrogen, oxygen (argon), and nitrogen content 4.2.1 shall be carried out in accordance with Article 4.2 of GB/T4844.3. It is allowed to use an ammonia ionization detector, or Gas chromatographs with discharge detectors or photoionization detectors can directly inject samples for measurement and comply with the following regulations:
Ensure that the content of each component in the carrier gas used should be about one order of magnitude lower than that of the sample to be tested. a.
b. The operating parameters of the instrument are selected according to the instrument instructions to ensure that the detection limit of each component to be measured is about one order of magnitude lower than the value specified in Table 1.
ensures that the chromatographic column is suitable for each group. The separation of points is greater than 1. c
d. The standard mixed gas is prepared with nitrogen as the base gas, and the content of each component to be tested should be close to the values ??specified in Table 1, and it should have a standard sample certificate from the State Administration of Technical Supervision. serial number.
When the inspection results are inconsistent with Article 4.2.1 (concentration method), or there is objection to the product quality, the method specified in GB/T4844.3 Article 4.2 e.
shall be the arbitration method.
4.3 Determination of carbon monoxide, carbon dioxide, and methane content 4.3.1 Determination of carbon monoxide, carbon dioxide, and methane content shall be carried out in accordance with the regulations of GB/T8984. When the peak height of each tested component cannot guarantee three significant digits, the provisions of Article 4.3 in GB/T4844.3 shall be followed. 4.3.2 It is allowed to use a gas chromatograph with a nitrogen ionization detector (HID) or photoionization detector (PID) for direct sample injection and measurement. The content of carbon monoxide, carbon dioxide, and methane in the carrier gas used should be about one order of magnitude lower than that of the sample to be tested. Other operating conditions are selected according to the instrument instruction manual to ensure that the detection limit (volume fraction) of each component is approximately 0.2×10-(V/V), the separation of each component is greater than 1, and the relative deviation of two parallel measurements is not greater than 10%, and its average value is used as the measurement result. 4.4 Determination of moisture content
shall be carried out in accordance with the provisions of GB/T5832.1.
5 Inspection Rules
5.1 Pure ammonia products shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard to ensure that the manufactured products meet the requirements of this standard. 5.2 Pure nitrogen products are inspected based on batch sampling. The batch size is the number of product bottles produced by one operation shift, or the number of product bottles per delivery. Samples submitted for inspection are randomly selected as specified in Table 2. 5.3 When any indicator of the unit (bottle) being inspected does not meet the requirements of this standard, the bottle product is unqualified. 5.4 When one bottle of the samples submitted for inspection fails, double samples from the same batch of products should be taken again according to Table 2 for re-inspection. If there are…- bottles that are unqualified, then the batch of products is unqualified. 5.5 Users have the right to inspect and accept products in accordance with the provisions of this standard. 5.6 When the supply and demand parties have objections to product quality, both parties shall negotiate for joint inspection and acceptance or submit to arbitration. 724
Product batch (bottle)
1～8
9 ~15
16~25
2650
>50|| tt||6 Packaging, marking, storage and transportation
GB4844.2—1995
Table 2 Sampling table
Sampling quantity (bottles)
2||tt| |3
4
5
6
6.1 The packaging, marking, storage and transportation of pure nitrogen products shall comply with the provisions of Chapter 6 of GB/T4844.1. 6.2 Cylinders filled with nitrogen should be marked with "Pure Nitrogen" and should have a plastic cap on the bottle mouth when leaving the factory. Additional notes:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Southwest Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard is drafted by the Southwest Chemical Research Institute of the Ministry of Chemical Industry and Weiyuan Natural Gas Chemical Plant of Sichuan Petroleum Administration Bureau. The main drafters of this standard are He Daoshan and Dai Qiwen. 725
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