GB 8334-1999 Periodic inspection and evaluation of liquefied petroleum gas cylinders
Some standard content:
GB8334—1999
Compared with the previous version, this standard mainly modifies the scope of application, adds the inspection content of small-volume liquefied petroleum gas cylinders; makes partial revisions to the evaluation method of liquefied petroleum gas cylinders; adds the content of secondary steam purging and initial and re-inspections of appearance, and adjusts the pressure of water pressure test and airtightness test according to GB11174-1997 "Liquefied Petroleum Gas". This standard replaces GB8334--1987 from the date of entry into force. Appendix A and Appendix B of this standard are the appendices of the standard. Appendix C of this standard is the appendix of reminder.
This standard is proposed and managed by the National Technical Committee for Standardization of Gas Cylinders. The drafting units of this standard are Dalian Boiler and Pressure Vessel Inspection Institute, Beijing University of Aeronautics and Astronautics, and Jinzhou Heavy Machinery Plant. The main drafters of this standard are Sun Pinghui, Tian Yongjiang, and Jiang Hongfu. This standard was first issued in December 1987. 206
1 Scope
National Standard of the People's Republic of China
Periodic inspection and evaluation of liquefied petroleum gas steel cylinders This standard specifies the basic methods and technical requirements for periodic inspection and evaluation of liquefied petroleum gas steel cylinders for civil use. GB8334--1999
Replaces GB8331--1987
This standard applies to refillable liquefied petroleum gas steel cylinders for civil use (hereinafter referred to as cylinders) with nominal volumes of 1.2L, 4.71L, 121L, 23.5L, 35.51L, 118L.
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 3864--1996I. Nitrogen industry
GB5842-1996 Liquefied petroleum gas cylinders
GB7144-1986 Gas cylinder color marking
GB7512--1998 Liquefied petroleum gas cylinder valve
GB/T8336--1998 Gas cylinder special thread gauge GB10878--1999 Gas cylinder taper thread tap
GB/T12137-1989 Gas cylinder air tightness test method GB15380-1994 Small volume liquefied petroleum gas cylinder GB /T9251—1997 Gas Cylinder Hydrostatic Test Method JB4730—1994 Nondestructive Testing of Pressure Vessels The former Ministry of Labor promulgated the "Gas Cylinder Safety Supervision Regulations" in 1989. 3 Inspection cycle and inspection items
3.1 For YSP-0.5, YSP-2.0, YSP-5.0, YSP-10 and YSP-15 steel cylinders in use, the inspection cycle from the first to the third inspection is 4 years from the date of manufacture, and the fourth inspection is valid for 3 years; for YSP-50 steel cylinders in use, the inspection is conducted every 3 years.
When the steel cylinder is severely corroded, damaged or has other defects that may affect safe use, it should be inspected in advance. Steel cylinders that have been in storage or out of use for more than one inspection cycle should be inspected before they are put into use. 3.2 The regular inspection items of steel cylinders include: appearance inspection, wall thickness measurement, volume measurement, hydrostatic test or residual deformation rate measurement, cylinder valve inspection, and air tightness test.
4 Inspection preparation
4.1 Check the manufacturing mark and inspection mark of each registered cylinder. The registration content includes the country of manufacture, the name of the manufacturer or the license number of the cylinder manufacturing license, the factory number, the hydraulic test pressure, the nominal working pressure, the actual weight, the actual volume, the designed wall thickness of the cylinder body, the year and month of manufacture, the material brand of the cylinder, and the date of the last inspection.
4.2 For cylinders manufactured by manufacturers not approved by the labor department, cylinders whose manufacturing marks do not comply with GB5842, GB15380 or the "Regulations on Safety Supervision of Gas Cylinders", and cylinders that are not allowed to be used according to relevant government documents, they will not be inspected after registration and will be scrapped. 4.3 For any type of cylinders with a service life of more than 15 years, they will not be inspected after registration and will be scrapped. 5 Initial inspection and assessment of appearance
5.1 Visual inspection of each cylinder (5.1.5 tools required) for easily discovered and assessed appearance defects. Cylinders that fall into any of the following categories shall be scrapped.
5.1.1 Cylinders without any manufacturing mark.
5.1.2 Cylinders with longitudinal welds or spiral welds. 5.1.3 Cylinders with ears or shields falling off or their welds broken, or cracks in the main welds. 5.1.4 Cylinders that are unable to stand upright due to base falling off, deformation, corrosion, cracking, wear and tear, or other defects. 5.1.5 Cylinders with a distance between the base support surface and the center of the bottom of the cylinder that is less than the size specified in Table 1. Table 1
YSP-0.5, YSP-2.0,YSP-5.0
YSP-10,YSP-15
YSP-50
5.1.6 Steel cylinders partially or fully burned by flame or arc (except manufacturing welds). 5.1.7 Steel cylinders with dents, scratches or pits deeper than those specified in 7.2.2.3 or with corrosion deeper than those specified in 7.2.2.7. 5.1.8 Steel cylinders with a dent deeper than 6mm on the main weld and within 50mm on both sides or with dents deeper than those specified in 7.2.2.4 and 7.2.2.5.
5.1.9 For cylinders with tilted or deformed bodies or with longitudinal wrinkles on the straight edges of the head with a depth greater than 0.25% of the outer diameter of the cylinder, 6 Residual liquid and residual gas recovery and steam purging
6.1 Under the premise of ensuring no leakage, no pollution to the environment, and no impact on the health of operators, appropriate sealing methods shall be adopted to recover the residual liquid and residual gas in the cylinders one by one.
6.2 For cylinders that have been scrapped after the initial appearance inspection, the residual liquid and residual gas in the cylinders must also be recovered one by one, and steam purged according to the requirements of 6.4 and 6.5. 6.3 When it is confirmed that the pressure in the cylinder is consistent with the atmospheric pressure, remove the cylinder valve and mark it for reinstallation into the original cylinder. When removing the cylinder valve, the detachable shield should generally not be removed; if it needs to be removed, it must be marked for reinstallation into the original cylinder. 6.4 Place the cylinder upside down on the steam purging device and use steam to purge the residual gas and residue in the cylinder. Steam pressure and purge time are determined according to process parameters. Under normal circumstances, steam pressure should be greater than or equal to 0.2MPa, and purge time should be greater than or equal to 3min6.5 Use a combustible gas detector to measure the residual gas concentration in the bottle after purge. Cylinders with a concentration higher than 0.4% (volume) must be re-steam purged.
7 Appearance re-inspection and evaluation
7.1 Preparation
7.1.1 Properly protect the manufacturing mark of the cylinder and the valve seat thread from damage. 7.1.2 Use a rust removal device that does not damage the bottle body to remove rust and coatings on the outer surface of the cylinder one by one. 7.2 Inspection
7.2.1 Valve seat
GB8334-1999
7.2.1.1 Use visual or low-power magnifying glass to check the condition of the valve seat one by one. The inspected bottles with cracks in the valve seat or sunken into the bottle body shall be scrapped. 7.2.1.2 Cracks or crack-like defects are not allowed in the thread, but no more than 3 teeth are allowed to be missing in the effective thread, and the length of the missing teeth shall not exceed 1/6 of the circumference, and the depth of the notch shall not exceed 1/3 of the tooth height. 7.2.1.3 If there is slight corrosion, wear or other damage to the thread, it can be repaired with a tap that complies with the provisions of GB10878. After repair, it must be inspected with a gauge that complies with the provisions of GB/T8336. Cylinders with unqualified inspection results shall be scrapped. 7.2.2 Appearance
7.2.2.1 Cracks, open flame burns, arc damage and volume deformation visible to the naked eye are not allowed on the bottle body. 7.2.2.2 The difference between the maximum and minimum diameters of the same section shall not exceed 0.01D: (inner diameter of the cylinder). 7.2.2.3 Cylinders with sulfur damage, scratches, and pits on the cylinder body whose remaining wall thickness is less than 90% of the design thickness should be scrapped. The measurement method is shown in Appendix B (Appendix Ting of the standard).
Defects that reach the scrap condition, especially linear defects or sharp mechanical damage, should be polished to make the edges smooth, but the wall thickness after polishing should be greater than 90% of the design wall thickness. 7.2.2.4 Cylinders with a dent depth exceeding 10mm or greater than 1/10 of the short diameter of the dent should be scrapped (see Appendix B for measurement method). 7.2.2.5 Cylinders with a dent or scratch depth greater than 0.4mm in a dent with a depth less than 6mm and dents with dents or scratches greater than or equal to 6mm should be scrapped. 7.2.2.6 Cylinders with a residual wall thickness of less than 2/3 of the design wall thickness at isolated pitting corrosion on the cylinder body should be scrapped. 7.2.2.7 Gas cylinders with residual wall thickness less than 90% of the designed wall thickness at the line corrosion or surface corrosion of the cylinder body shall be scrapped. 7.2.3 Welds
7.2.3.1 The appearance inspection of welds must be carried out one by one, and those with the following defects shall be scrapped: a) There are cracks, pores, arc pits, slag inclusions or unfused defects in the weld and its heat affected zone; b) There is an undercut defect on the main weld or component weld on one side of the cylinder body; c) There are depressions or irregular mutations on the weld surface; d) There are scratches with a depth greater than 0.5mm or depressions with a depth greater than 6mm within 50mm on the main weld and both sides. 7.2.3.2 The appearance quality of the longitudinal weld of 118L steel cylinders and its intersection with the girth weld should be inspected in detail. 7.2.3.3 Weld superelevation, spatter on both sides of the weld or other superelevation defects can be ground and smoothly transitioned to the parent material. 7.2.3.4 When there is doubt about the type and severity of weld defects, other non-destructive testing methods should be used for re-inspection, and the detection rate should not be less than 20%. According to JB4730, the plate grade is qualified. 8 Wall thickness measurement
8.1 The wall thickness of the cylinder must be measured. 8.2 The error of the thickness gauge should not be greater than ±0.1mm. 8.3 The thickness measurement point should be selected at one point in the arc transition zone of the upper and lower heads, and the cylinder should be selected at one point 50mm away from both sides of the circumferential weld; for cylinders with severe corrosion, two points should be selected in the arc transition zone of the upper and lower heads. Three points should be selected for the cylinder; two more points should be added for the lower part of the cylinder of the 118L cylinder and the arc transition zone of the lower head. Cylinders with residual wall thickness less than 90% of the designed wall thickness after measurement should be scrapped. 9 Volume measurement
9.1 The volume of the cylinder must be measured. 9.2 The weighing instrument used for volume measurement should be kept accurate, and its maximum weighing value should be 1.5 to 3.0 times the commonly used weighing value. The calibration period of weighing instruments shall not exceed three months.
9.3 The volume measurement adopts the water volume measurement method C (see Appendix A (Appendix of the standard)]. 9.4 The steel cylinder whose current volume is less than the value specified in the standard should be scrapped. 209
10 Water pressure test or volume residual deformation rate measurement GB 8334--1999
10.1 Steel cylinders must be subjected to water pressure test or volume residual deformation rate measurement one by one. The methods, facilities and safety measures for water pressure test and volume residual deformation rate measurement shall comply with the requirements of GB/T9251. 10.2 The water pressure test pressure is 3.2MPa, and the pressure holding time shall not be less than 1min. 10.3 During the hydraulic test, cylinders with leakage, obvious deformation or pressure drop during the pressure maintenance period (not due to leakage of the test device, cylinder valve or bottle mouth) shall be scrapped.
10.4 When the volume residual deformation rate is determined by the internal measurement method or the external measurement method, cylinders with a volume residual deformation rate exceeding 10% shall be scrapped. 10.5 For cylinders that have passed the hydraulic test, the cylinder mouth should be turned upside down for a period of time to allow the residual water in the bottle to flow out. 11 Cylinder valve inspection and assembly
11.1 Cylinder valves must be disassembled for inspection, cleaning and replacement of damaged parts one by one to ensure free opening and closing without leakage. 11.2 The valve body and other parts shall not be severely deformed, and the threads shall not be severely damaged. The requirements shall be in accordance with the provisions of 7.2.1.2. 11.3 When replacing cylinder valves or sealing materials, the provisions of GB7512 must be met. 11.4 The cylinder valve should be firmly assembled and ensure the effective number of threads and sealing performance of its connection with the valve seat. After assembly, the number of exposed threads should be no less than 1 to 2 threads.
11.5 After the cylinder valves are inspected, cleaned and replaced, they are assembled and tested for air tightness in the closed state, opening and closing process and fully open state. The test pressure is 2.1MPa, and the pressure holding time is no less than 1min. No leakage is allowed. 12 Air tightness test
12.1 The cylinder to be tested must be a steel cylinder that has passed the appearance re-inspection and water pressure test or residual deformation rate measurement. Otherwise, it is strictly prohibited to conduct air tightness test.
12.2 The compressed air used for air tightness test shall not contain oil and water; the purity of the nitrogen used shall not be lower than the Class 1 secondary index specified in GB/T3864-1996.
12.3 For all steel cylinders that use air as the medium for air tightness test, the concentration of gas released by the residue in the bottle must be measured before the test. For steel cylinders with a concentration greater than 0.4% (volume), a secondary steam purge must be carried out. Only after the concentration meets the requirements can the test be carried out with air, otherwise the test must be carried out with nitrogen.
12.4 After confirming that the gas concentration in the steel cylinder meets the requirements, the qualified bottle valve shall be tightly installed on the bottle to be tested. 12.5 The gas tightness test of the steel cylinder adopts a waterless test, and its filling device, test water tank, test conditions and methods must comply with the regulations of GB/T12137.
12.6 The gas tightness test pressure is 2.1MPa, and the pressure holding time shall not be less than 1min. During the pressure holding process, the pressure gauge is not allowed to drop; steel cylinders with drowned or deformed bottles shall be scrapped. Steel cylinders that leak due to improper assembly of the bottle valve are allowed to be reassembled before testing.
13 Work after inspection
13.1 Inspection mark
13.1.1 All cylinders that have passed the inspection must be marked with an inspection mark that is not easy to damage, not easy to lose, and has clear handwriting. The content includes the inspection unit code, the current and next inspection dates (year, month, day). 13.1.2 The printing position and method of the inspection mark shall depend on different situations: the inspection unit with a rolling device can roll the inspection mark on the appropriate position of the upper head shoulder of the cylinder. For cylinders with soft metal sign plates welded on the upper head shoulder, the inspection mark should be printed on the specified position of the sign plate by special machinery or manual methods; for old-style cylinders that were originally designed without shields or whose shields are detachable, the inspection mark should be printed on the inspection mark ring on the conical tail of the cylinder valve by special machinery or manual methods [refer to Appendix C (Suggested Appendix) for external dimensions] t; for new-style cylinders with wings welded on the shoulders, the inspection mark should be printed on the shield by special machinery. 210
GB8334—1999
13.1.3 In addition to printing the inspection mark in accordance with 13.1.2, a 5mm diameter inspection mark hole must be drilled at the following specified locations. For cylinders without shields or with removable shields, the inspection mark hole should be drilled on the base, and the year of this inspection should be stamped on the left side of the hole. For cylinders with shields welded to the shoulders, the inspection mark hole should be drilled at the end of the year and month of this inspection. 13.1.4 The height of the stamped font should be 5~10mm and the depth should be 0.3~0.5mm. 13.2 Re-coating
13.2.1 For cylinders that have passed the inspection, remove dust, oil stains, rust, impurities such as oxide scale and welding spatter left during manufacturing, and apply the coating in a dry state. 13.2.2 In addition to the provisions of GB7144 and CJ/T34, the coating must also be carried out in accordance with the following provisions: 13.2.2.1 The height of the red word "Liquefied Petroleum Gas" is 60~~80mm in Fangsong font. 13.2.2.2 The coating should be sprayed evenly in two layers, and no defects such as bubbles, flow marks, cracks or peeling should appear. 13.2.2.3 When applying the paint color of the cylinder, the inspection color standard must be sprayed on the part where the inspection mark is rolled or printed. When using the inspection ring, it should be sprayed on the shield.
13.3 Cylinder inspection record and scrapping
13.3.1 The cylinder inspector must fill in the cylinder inspection results item by item in the "Liquid Petroleum Gas Cylinder Periodic Inspection Record" and fill in the inspection report and submit it to the property unit for filing.
13.3.2 The inspection unit shall be responsible for destroying the scrapped gas cylinders by flattening or sawing them, and shall fill in the "Gas Cylinder Waste Notice" in accordance with the provisions of Appendix 4 of the "Gas Cylinder Safety Supervision Regulations" to notify the gas cylinder property unit. 13.3.3 Inspection units are strictly prohibited from welding or repairing steel cylinders. 211
GB8334—1999
Appendix A
(Standard Appendix)
Method for measuring the water volume of steel cylinders
The volume of steel cylinders must be measured after removing the rust and contamination in the cylinder to avoid errors. The measurement method is as follows: a) Place the steel cylinder that has been weighed empty upright on the floor of the inspection room, fill the bottle with clean water, and let it stand for 24 hours. During this period, the bottle wall should be tapped from bottom to top several times with a wooden hammer, and the water in the bottle should be filled up each time until the water level at the bottle mouth stops dropping. b) After confirming that the bubbles in the bottle have been eliminated and the liquid level in the bottle door has stopped dropping, move the gas cylinder to a weighing scale to weigh the total weight of the bottle and the water. c) Subtract the measured weight of the empty bottle from the total weight of the bottle of water to get the weight of the water in the bottle, and then multiply it by the volume of each dry gram of water at the water temperature in the bottle when weighing (see Table A1).The current volume of the cylinder is obtained. Table A1 Volume of water per kilogram at different water temperatures Temperature,
Temperature, C
Volume,
Temperature, C
Appendix B
(Standard Appendix)
Volume,
Measurement method of the depth of depression, pit, gouge and scratch B1 Measurement method of depression depth (h)
Temperature, C
Volume, L
1. 004.97
1. 007 06
Measure the depth with the chord of the depression as the reference. The measuring tool is a height vernier caliper or a ruler. The ruler should be placed along the axis of the cylinder. The length of the ruler should be greater than three times the maximum diameter of the depression, as shown in Figure B1a). The depth is measured based on the arc of the outer circumference of the cylinder body at the concave part. The measuring tool is an arc-shaped template. The arc-shaped template should be placed along the circumference. The arc length of the template should be greater than 2/5 of the circumference of the cylinder, as shown in Figure B1b). 212
Vernier caliper
Steel ruler
h—Deepness of concave
Cylinder bodywww.bzxz.net
2 Method for measuring the depth of pits, dents and scratches B2
Any of the following two methods can be used: GB8334-1999
Outer surface of steel cylinder
a) The depth of pits, dents and scratches is based on the deepest depth. The special measuring tool for measurement is shown in Figure B2. The radius of curvature of the profile of the card plate coincides with the outer contour of the steel cylinder. The needle tip of the micrometer is inserted into the defect to measure its depth. The wedge angle of the needle tip should be less than or equal to 30° and the radius should be less than or equal to 0.25mm. During the measurement process, the reading of the micrometer should be checked regularly to eliminate the error caused by needle tip wear. Micrometer
Special card
b) Hammer the soft solder into the pit, bump, or scratch, remove the soft lead, and use a caliper to measure the maximum soft lead height, which is the measured depth value. 213
GB8334—1999
Appendix c
(Suggested Appendix)
Inspection mark ring
The outer dimensions of the inspection mark ring of the cylinder are shown in Figure C1, and its material is aluminum. The inspection mark is the inspection unit code and the inspection year and month. +
Amendment No. 1 to GB8334-1999 "Periodic Inspection and Assessment of Liquefied Petroleum Gas Cylinders"
This amendment was approved by the Standardization Administration of the People's Republic of China on January 8, 2002 in the document [200211] of the Standardization Administration of the People's Republic of China, and will be implemented from April 1, 2002.
Comparison table of modified clauses
Before modification
Article 3.1 "…From the date of manufacture, the inspection cycle from the first to the third inspection is 4 years, and the validity period of the fourth inspection is 3 years:" Article 5.1.2 "For steel cylinders with longitudinal welds or spiral welds." Appendix A\) Fill the bottle with clean water and let it stand for 24h214
After modification
Article 3.1
The inspection cycle from the date of manufacture to the third inspection is 4 years, and the validity period of the third inspection is 3 years;" "For steel cylinders with longitudinal welds (except for YSP-50 steel cylinders in Article 5.1.2
)."
Appendix Aa) "Fill the bottle with clean water and let it stand for 8h (the clean water poured into the bottle should have been allowed to stand in the test water tank for one hour). "
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