This standard specifies the structure, volume, technical requirements, test methods, inspection rules, marking, packaging and storage of cylindrical positive pressure samplers for gas detection tubes. This standard applies to cylindrical positive pressure samplers for gas detection tubes (hereinafter referred to as samplers) used in conjunction with longer gas detection tubes. It also applies to the positive pressure part of cylindrical negative pressure and positive pressure dual-purpose samplers. MT/T 629-1996 Technical conditions for cylindrical positive pressure samplers for gas detection tubes MT/T629-1996 Standard download decompression password: www.bzxz.net

MT/T629-1996
The gas detection tube used to detect certain gases in the air must be injected into the detection tube with a matching gas sampler. According to the appearance of the gas sampler, there are two types: round and bellows. According to the way of injecting gas into the gas detection tube, there are the so-called "push-in", "vacuum" and "suction" methods. In order to standardize its name, prevent confusion, and be consistent with the gas injection method required by the detection tube, this standard names all the methods of injecting the measured gas into the gas detection tube with a pressure higher than the atmosphere as "positive pressure type", and the method of injecting the measured gas into the gas detection tube with a pressure lower than the atmosphere as "negative pressure type". This standard is proposed by the Science and Technology Education Department of the Ministry of Coal Industry. This standard is under the jurisdiction of the Coal Mine Safety Standardization Technical Committee. The drafting unit of this standard: Fushun Branch of the China Coal Research Institute. The main drafter of this standard: Yang Wenzheng.
This standard is entrusted to Fushun Branch of the China Coal Research Institute for interpretation. 383
Coal Industry Standard of the People's Republic of China
Technical Conditions for Cylindrical Positive Pressure Samplers for Gas Detection Tubes
MT/T629---1996
This standard specifies the structure, volume, technical requirements, test methods, inspection rules, marking, packaging and storage of cylindrical positive pressure samplers for gas detection tubes.
This standard applies to cylindrical positive pressure samplers for gas detection tubes (hereinafter referred to as samplers) used in conjunction with longer gas detection tubes. It also applies to the positive pressure part of cylindrical negative pressure and positive pressure dual-purpose samplers. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB723087 Gas detection tube device
GB/T10111-88 Random sampling method using random numbers 3 Structure, volume
3.1 The structure of the sampler is shown in Figure 1.
After the gas to be measured is inhaled into the sampler, the three-way valve passage is changed to press the gas sample to be measured into the gas detection tube. 3
1—Detection tube insertion port; 2—Gas sampling port; 3—Three-way valve; 4—Piston; 5—Round cylinder: 6—Handle
Schematic diagram of cylindrical positive pressure sampler
3.2 The nominal volume of the sampler is 50mL (100mL). 4 Technical requirements
4.1 The sampler shall comply with the requirements of this standard and be manufactured according to the drawings and technical documents approved by the prescribed procedures. 4.2 General requirements:
Ministry of Coal Industry of the People's Republic of China approved 384 on 1996-12-30
199711-01 implementation bzxZ.net
MT/T 629—1996
4.2.1 The sampler surface shall not have obvious defects such as peeling, discoloration and scratches. 4.2.2 The sampler parts shall not be loose. The three-way valve shall rotate flexibly. 4.2.3 The handle of the sampler shall be able to push and pull freely in the cylinder. When pressing the gas sample into the detection tube, the speed shall be evenly controlled. 4.3 Performance requirements:
4.3.1 The relative error of the sampler volume shall not be greater than ±5% of its nominal volume. 4.3.2 The leakage of the sampler per minute shall not be greater than 3% of the measured volume. 4.3.3 After the durability test, the performance of the sampler shall still meet the requirements of 4.3.1 and 4.3.2. 4.3.4 The operating temperature range of the sampler is 5-40℃. After the temperature test, its performance shall still meet the requirements of 4.3.1 and 4.3.2. 5 Test method
5.1 The test environment temperature is 15-30℃, and the atmospheric pressure is 86-106kPa. 5.2 General inspection is carried out with sensory organs and during operation. 5.3 Performance inspection.
5.3.1 Volume measurement:
In the insertion port of the detection tube of the sampler, tightly insert a glass capillary with an inner diameter of 0.4~～0.5mm and a length of 100-120mm. The other end of the glass capillary is connected to the lower inlet of a soap film flowmeter with a capacity of 55mL (or 110mL) and a minimum scale of 0.2mL (as shown in Figure 2). At the beginning of the test, the sampler is filled with air and the soap film is stabilized at the position of the scale "0". Then the air in the sampler is exhausted and the soap film rises. When the air in the sampler is completely exhausted, the value indicated when the soap film stops moving is the measured volume of the sampler. Repeat 3 times and take the arithmetic mean, which is the measured volume of the sampler. The relative error (X,%) with the nominal volume is calculated according to formula (1).
X% =×100
Where: V. ——Nominal volume of the sampler, mL; Vi—Measured volume of the sampler, mL.
1Zero position; 2—Scale; 3—Glass capillary: 4—Sampler; 5—Soap solution Figure 2 Schematic diagram of sampler volume measurement
5.3.2 Leakage measurement.
Insert a detection tube with both ends opened into the detection tube insertion port of the sampler. Connect the other end of the detection tube to the lower outlet of the soap film flowmeter described in 5.3.1. Perform the exhaust operation according to the method described in 5.3.1 and start the timer. After the specified time is reached, record the scale value indicated when the soap film stops moving, which is the volume of gas discharged by the sampler. Repeat 3 times and take the arithmetic mean, which is the volume of gas passing through the gas detection tube. The percentage of the sampler's leakage volume per minute to the sampler's measured volume (X2%) is calculated according to formula (2). 385
MT/T 629--1996
(V/ - V2) × 60
× 100
Where: V. - the volume of gas passing through the gas detection tube, mL; the specified measurement time, s.
5.3.3 Durability test:
Insert a detection tube with both ends open at the detection tube insertion port of the sampler, repeat the suction and exhaust operation 100 times, and then measure the volume and leakage according to the methods in 5.3.1 and 5.3.2. 5.3.4 Temperature test:
Put the sampler in an environment of 5℃ and 40℃ for 8h, take it out and restore it to room temperature, and then measure the volume and leakage according to the methods in 5.3.1 and 5.3.2.
5.4 Data processing.
5.4.1 When measuring the volume and leakage of the sampler, the significant figures are retained to 1 decimal place. 5.4.2 When calculating the relative error of the sampler volume and the leakage per minute, calculate to 2 decimal places and round to 1 decimal place. 6 Inspection rules
The inspection of the sampler is divided into factory inspection and type inspection. 6.1 Factory inspection
6.1.1 The sampler shall be inspected by the factory quality inspection department. It may leave the factory only after passing the inspection and issuing a certificate of conformity. 6.1.2 Factory inspection items include 4.2 and 4.3.1, 4.3.2. 6.2 Type inspection
6.2.1 Type inspection shall be carried out in any of the following situations: - When a new product or old product is transferred to the factory for trial production and identification; - After formal production, if there are major changes in structure, materials, and processes that may affect the performance of the sampler; - During normal production, an inspection shall be carried out every two years, and when production is resumed after one year of suspension;
When the factory inspection results are significantly different from the last type inspection; - When the national quality supervision agency makes a request for type inspection. 6.2.2 Type inspection items include 4.2 and 4.3. 6.3 Sampling
6.3.1 Factory inspection sampling
Three units (pieces) shall be sampled from the assembled products according to the method specified in GB/T10111. 6.3.2 Type inspection sampling
Three units (pieces) shall be sampled from the products that have passed the factory inspection according to the method specified in GB/T10111. 6.4 Judgment rules
When the type inspection is conducted, if two of the seven items in 4.2 and 4.3 are unqualified, the product shall be judged as unqualified. If one item is unqualified, double sampling shall be conducted to re-inspect the unqualified items. If one item is still unqualified, the product shall be judged as unqualified. 7 Marking, packaging, storage
7.1 Marking
7.1.1 Product marking:
The marking on each sampler (piece) shall include: product name, model;
Nominal volume;
Manufacturer name, factory number;
MT/T 629—1996
Factory inspection certificate number, inspection date, inspector code. 7.1.2 Product packaging sleeve marking:
The marking on each sampler (piece) packaging sleeve shall include: product name, model, nominal volume, number; manufacturer name;
Measuring instrument mark and manufacturing license number. 7.1.3 Packaging box markings: The markings on the sampler’s factory packaging carton should include: product name, model, nominal volume; quantity, gross weight, kg; volume (length × width × height), mm, manufacturer’s name and address; date of manufacture; words and marks such as “handle with care” and “afraid of moisture”. 7.2 Packaging 7.2.1 Each sampler should be placed in a leather or artificial leather case. In addition to the sampler, the case should also contain the instruction manual for use with the test tube and necessary spare parts. 7.2.2. The samplers placed in the case should be placed in a cardboard box according to a certain number and fixed with soft objects without shaking. 7.3 Purchased and stored Samplers should be stored in a dry room at room temperature. 387
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