MT 398-1995 Glass transparent parts for explosion-proof lamps for coal mines
Some standard content:
Coal Industry Standard of the People's Republic of China
Glass transparent parts of explosion-proof lamps for coal mines
1 Subject content and scope of application
MT 398--1995
This standard specifies the product classification, technical requirements, test methods, quality assessment rules, packaging, transportation and storage of glass transparent parts of explosion-proof lamps for coal mines (hereinafter referred to as transparent parts). This standard applies to glass transparent parts of explosion-proof lamps for coal mines. This standard does not apply to transparent parts of mining lamps. 2 Reference standards
GB2828 Count sampling procedure and sampling table for batch inspection (applicable to inspection of continuous batches) GB2829 Count sampling procedure and sampling table for periodic inspection (applicable to inspection of stability of production process) GB3836.1 General requirements for explosion-proof electrical equipment for explosive atmospheres GB7004 Technical conditions for wooden box packaging of lamps
GB7256.1 General requirements for technical conditions of lamps for civil airports SG386 Technical conditions for corrugated box packaging of lamps 3 Product classification
3.1 According to the manufacturing process, it can be divided into blowing, pressing and drawing. 3.2 According to the shape after forming, it can be divided into semicircular, oblate, round and flat shapes. 3.3 According to the color after forming, it can be divided into transparent, red, green and yellow. 3.4 According to the processing technology, it can be divided into tempered or annealed. 4 Technical requirements
4.1 Transparent parts must meet the requirements of this standard and be manufactured according to the drawings and documents approved by the inspection unit designated by the state. 4.2 Transparent parts (except "tempered") must eliminate internal stress, and blue, purple, red and pink are qualified when observed by polarimeter or stress meter. 4.3 The chromaticity coordinates of red, green and yellow colored transparent parts shall comply with the provisions of Article 3.10 of GB7256.1. 4.4 After the transparent parts are formed, the light transmittance of the circular shape shall be greater than or equal to 85%, and the light transmittance of other shapes shall be greater than or equal to 80%.
4.5 The impact energy of transparent parts after forming shall comply with the relevant provisions of Table 5 in Article 21.1 of GB3836.1. 4.6 The thermal shock test of transparent parts after forming shall comply with the provisions of Article 19.1b of GB3836.1. 4.7 The allowable defect range of the main surface of transparent parts after blow forming (see Table 1). 4.8 The allowable defect range of the main surface of transparent parts after press forming (see Table 2). 4.9 The allowable defect range of the main surface of transparent parts after drawing forming (see Table 3). Note: The surface that can be directly seen after the lamp is installed is called the main surface. Approved by the Ministry of Coal Industry of the People's Republic of China on August 22, 1995, 72
Implemented on November 1, 1995
Bubble ≥~16
Width <3. Length ≤15
Width 3, Length 25
Gas line width <3. Length ≤40
Width 4～~5, Length ≤30
Width 4~5. Length ≤40
Knot ≥2
Width ≤1/week
Width>1～2/week
Defect name
≤300 cm2
MT 398--1995
Allowable number of defects
1000 cm2
>1 000～
2000cm2
1≥2 000～
3 000 cm\
Allowable number of defects
≤300cm2
>300~500 cm2
>3 000 cm2
Main surface≤1000cm2
Defect spacing≥30mm
Main surface1000cm2
Defect spacing≥50mm
Main surface≤1000cm2
Defect spacing≥30mm
Main surface>1000cm
Defect spacing50mm
Defect spacing≥50mm
Defect spacing≥30mm
Defect spacing≥50mm
>500 ~1 000 cm2≥1 000 cm2
Interval ≥40mm
Interval ≥30mm
Defect name
Width <2.Length ≤40
Width ≥3.Length 80
Width 81/week
Width >1~2/week
≤300cm2
MT 398—1995
Allowable number of defects
>300~500 cm
>500 cm2
Defect spacing 240mm
Defect spacing ≥40mm
Defect spacing ≥30mm
Defect spacing ≥30mm
Defect spacing ≥30mm
Note: (The diameters of bubbles and stones in the table are average values.② The area value in the table is the unfolded area of the main surface of the tested transparent part (when the transparent part and the lamp are assembled without restrictions, its full surface is the main surface). The transparent part shall not have the following defects after forming: 4.10
Not blown enough and not pressed enough;
cracks and cracked stones;
rust spots;
obvious cold marks;wwW.bzxz.Net
obvious bumps;
obvious pitting;
obvious scratches;
broken bubbles (including thin bubbles that can be broken by fingers). Transparent parts are not allowed to be made into threaded structures. Test method
5.1 Layer test sleeve (Articles 4.1, 4.7, 4.8, 4.9, 4.10) is carried out with the naked eye and general measuring tools that meet the accuracy requirements. 5.2 Internal stress test (Article 4.2)
Observe and check with a polarimeter or stress meter.
5.3 Color measurement test of colored transparent parts (Article 4.3) is carried out in accordance with the requirements of Article 4.12 of GB7256.1. 5.4 Light transmittance test (Article 4.4)
Measured by photometer system.
5.5 Impact test (Article 4.5)
MT 398-1995
Performed in accordance with the relevant provisions of Articles 21.1 and 21.3 of GB3836.1. 5.6 Thermal shock test (Article 4.6)
Performed in accordance with the requirements of Article 24.3 of GB3836.1. 6 Quality assessment rules
6.1 Inspection classification
The quality assessment rules for products include two types of inspections, identification inspection and quality consistency inspection. 6.2 Identification inspection
Identification inspection is a series of complete inspections carried out on several samples of a certain specification, which should include all test items specified in the identification inspection of this standard. Its purpose is to To determine whether the design of the product meets the requirements of this standard and whether the manufacturer is capable of producing products that meet the requirements of this standard.
6.2.1 Identification and testing should be carried out in any of the following situations. a.
Identification of the finalization of the technical safety performance of new products; after formal production, if there are major changes in shape, materials, and processes that may affect product performance; b.
When the national quality supervision agency makes a request. 6.2.2 Samples for identification and testing can be selected by the manufacturer from the trial products. Except as specified in the standard, relevant test items should be carried out on single samples.
6.2.3 Test items and test sequence shall be in accordance with Table 4. Table 4 Test items Correctness of drawing Permissible defect range after blow forming Permissible defect range after straight forming Permissible defect range after drawing Permissible defect range after forming Defects that must not exist Internal stress test Chroma measurement test Transmittance test Punching test Thermal shock test Technical requirements Items Test method Specification Identification test 6 .2.3 If all items of the inspection are passed, it is judged as qualified. If one of them fails, it is judged as unqualified. 6.2.4
If the inspection is not carried out as required or all the required test items are not completed, no judgment can be made. 6.2.5 Samples that fail the identification inspection shall be resubmitted for inspection after improvement. During the re-inspection, the unqualified items and their related items can be inspected. After several inspections are summarized and all the test items are passed, it can be judged as qualified. However, the time from the first identification inspection to the last resubmission inspection shall not exceed half a year.
6.3 Quality-Conformity Inspection
MT 398-1995
Quality consistency inspection is based on batch inspection. Samples are taken periodically from the product to determine whether the product quality can be guaranteed to be stable during the production process. Quality consistency inspection consists of "batch inspection" and "periodic inspection". 6.3.1 Batch inspection
6.3.1.1 The full inspection items in batch inspection are the 4th item in this standard.1. 6.3.1.2 The sampling items of batch inspection shall be in accordance with the general inspection level 1 and the sampling plan in GB2828. The sampling shall be carried out on the products that have passed the full inspection.
6.3.1.3 The sampling items, sequence and AQL value of batch inspection shall be in accordance with the provisions in Table 5. Table 5
Test items
Permissible defect range after blow forming
Permissible defect range after H forming
Permissible defect range after drawing
Defects that must not exist after forming
Technical requirements items
Test method items
6.3.1.4 Inspection strictness of random inspection. The retrieval of sampling plan, the extraction of samples, the inspection of samples, the judgment of qualified or unqualified batch by batch inspection, and the disposal after batch by batch inspection shall apply the provisions of Articles 4.6, 4.8, 4.9, 4.10, 4.11 and 4.12 of GB2828. 6.3.2 Periodic inspection
6.3.2.1 It shall be carried out every three years. When any of the following situations occurs, a periodic inspection shall be carried out in time. a.
Test group
When the batch inspection results are significantly different from the last periodic inspection; when production is resumed after two years of suspension;
When the quality supervision agency of Fujian Province makes a request. Periodic inspections shall be carried out in accordance with the provisions of GB2829, discrimination level 1, and sampling plan. The grouping, sequence and RQL value of periodic inspection items shall be carried out in accordance with the provisions in Table 6. Table 6
Test Items
Colorimetric Test
Transmittance Test
Internal Stress Test
Impact Test
Thermal Shock Test
Technical Requirements Items
Test Method Items
Sample Size
Judgment Array
6.3.2.4 Sample extraction for periodic inspection, sample inspection, qualified or unqualified judgment, and post-inspection disposal shall be subject to the provisions of Articles 4.9, 4.10, 4.11, and 4.12 of GB2829. 76
7 Packaging, Storage and Transportation
7.1 Packaging and Storage
MT 398-1995
7.1.1 When packaging and storing in corrugated boxes, the relevant provisions of SG386 shall be met. 7.1.2 When packing and storing in wooden boxes, the relevant provisions of GB7004 shall be met. 7.2 Transportation
Severe vibrations must be avoided during transportation, and the equipment should be handled with care during loading and unloading. Additional remarks:
This standard was proposed by the Coal Mine Special Equipment Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the jurisdiction of the Electrical Equipment Branch of the Coal Mine Special Equipment Standardization Technical Committee. This standard was drafted by Shanghai Liaoyuan Lighting Factory and Shanghai Branch of the China Coal Research Institute. The main drafters of this standard are Fu Meijuan, Zhou Hongyao, Lu Jinqi and Le Weiliang. 77
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