Some standard content:
Machinery Industry Standard of the People's Republic of China
Inspection and Testing of Gas Cylinder Valve
1 Subject Content and Applicable Scope
This standard specifies the inspection, test methods and inspection rules of gas cylinder valves . JB/T 6904 --- 93
This standard applies to gas cylinder valves used on re-inflatable mobile gas cylinders (hereinafter referred to as valve). 2 Reference standards
GB 7512
GB8335
GB 8336
GB 8337
GB10877
GB 10879
GB 10922
GB 13438
GB 13439
Liquefied petroleum gas cylinder valve
Special thread for gas cylinder
Special thread gauge for gas cylinderbzxZ.net
Gas cylinder Use soluble alloy plug
oxygen cylinder valve
dissolved acetylene cylinder valve
non-thread-sealed pipe thread gauge
argon cylinder valve
liquid Chlorine cylinder valve
3 Inspection and test methods
3.1 Appearance inspection
The appearance of the valve shall be inspected visually. If any of the following conditions occurs, the product shall be deemed unqualified: a.|| tt||Components and parts are missing or the assembly does not comply with the drawing requirements; b. The valve is severely bruised and has defects that affect valve performance; ℃. Obvious thread defects in the air inlet and outlet. 3.2 Inspection of connecting threads
The threads used to connect the valve and the gas cylinder should be inspected with a gauge that complies with GB8336. The thread of the cylindrical pipe at the valve outlet should be checked with a gauge complying with GB10922. When the air outlet of the valve has other threads, it should be checked with gauges that comply with the corresponding standards.
3.3 Opening and closing torque inspection
After installing the valve on a special device, close the valve with a torque not exceeding 1Nm. For valves with a needle structure, use a torque not exceeding 12Nm. The air inlet of the valve is filled with nitrogen or air to the nominal working pressure and immersed in water for 30°C without leakage; then the valve should be able to be opened smoothly according to the above torque regulations. The accuracy error of the torque wrench is ±5%. 3.4 Air tightness test
Install the valve on a special device and conduct the test according to the following two methods: When the valve is in a closed state, fill nitrogen or air from the valve inlet to the nominal working pressure, and immerse it in water for 30 There should be no leakage at the air outlet a.
of the $ bottle valve;
The Ministry of Machinery Industry of the People's Republic of China approved 672 on 1993-07-13
and was implemented on 1994-07-01
JB/T 6904 -- 93
When the valve is in the open state, seal the valve outlet with a plug cap, fill nitrogen or air from the valve inlet to the nominal working pressure, and immerse b.
There should be no leakage between the valve stem and the pressure cap, between the pressure amplitude and the valve body and other parts in the water for 30 seconds. 3.5 Vibration resistance test
Install the valve on a special device, keep the valve in a closed state, fill nitrogen or air from the valve inlet to the nominal operating pressure; then set the Hz, amplitude to 2mm, any Vibrate in one direction for 30 minutes. Each connecting device on the valve is installed on the vibration test bench. There should be no looseness or leakage at the vibration frequency of 33.
3.6 Temperature resistance test
Install the valve on a special device, keep the valve in a closed state, fill the valve inlet with nitrogen or air to the nominal working pressure, and place it in the overflow tank. Make the temperature reach 60°C ± 2°C and -40°C ± 2°C respectively, and keep them warm for 2 hours each (open and close for 1 hour each). The valve should meet the air tightness test requirements of Article 3.4 after high and low temperature tests. 3.7 Pressure resistance test
Connect the air inlet of the valve to the pressure test pump. For valves with safety devices, the safety device should be removed and replaced with a blocking cap; the air outlet should be closed to keep the valve open. Fill the valve with hydraulic pressure to 2 times the nominal working pressure for 3 minutes. There should be no leakage or other abnormal phenomena in the valve body and connections. Note: The test medium is water or other suitable liquids with a viscosity no greater than water. 3.8 Durability test
Install the valve on a special device, close the air outlet, keep the valve in an open state, fill nitrogen or air from the valve inlet to the nominal working pressure, and then install the special device on the durability On the test bench, according to the specified torque and the number of times specified in Table 1, the full-stroke opening and closing valve is tested and meets the requirements of Table 1.
Table 1 Durability times
Class
Type
Diaphragm type
Needle form
Other forms
Tested The opening and closing frequency is 2~30 times/min. Number of opening and closing times in the whole stroke (n)
1000
4000
Result
Result
There should be no leakage and other abnormal phenomena
For valves with a needle structure, if leakage occurs at the pressure cap and valve stem during the durability test, the pressure cap is allowed to be tightened to the specified torque until the leakage disappears, and the test can be continued. 3.9 Safety device action test
For bottle valves that require safety device action, a safety device action test should be performed. 3.9.1 When the safety device is a fusible alloy plug type test, install the valve on a special device, keep the valve in a closed state, fill nitrogen or air from the valve inlet to 0.4MPa, and place the special device into a container of glycerol. Gradually heat up the tank and make it uniform. When the temperature is 95C ± 5℃, the safety device should operate. 3.9.2 When the safety device is a diaphragm or spring type test, connect the valve to the hydraulic pump and fill it with hydraulic pressure to 1.2 to 1.5 times the nominal working pressure. The safety device should act. 3.10 Vacuum test
For bottle valves with vacuum requirements, a vacuum test should be performed. The test device is shown in Figure 1. First install the valve outlet on the tee joint, keep the valve in a closed state, start the vacuum pump, the vacuum degree of the valve should reach 98053.2×10°MPa, or a higher vacuum degree requirement; then use Block the cap, keep the valve in the open state, and operate the vacuum pump. The vacuum degree of the valve should also reach the vacuum degree requirement of 98053.2×10°MPa or higher. Note: The accuracy level of the pressure gauge used in the above test is 1.5. 673
Vacuum Gauge
4 Inspection Rules
Valve
Valve inspection is divided into inspection and type inspection. 4.1 Factory inspection
JB/T 6904—93
Figure 1
The valve must pass the production inspection and be accompanied by a certificate of conformity before leaving the factory. Factory inspection requires piece-by-piece inspection.
4.1.1 Appearance inspection shall be in accordance with Article 3.1.
4.1.2 Inspection of connecting threads shall be in accordance with Article 3.2. 4.1.3 The air tightness test shall be carried out in accordance with Article 3.4. 4.2 Spot check inspection
In addition to the factory inspection items, the spot check inspection content should also include the following content: a.
Temperature resistance test shall be in accordance with Article 3.6,
Safety device action test shall be in accordance with 3.9 provisions. h.
4.3 Spot check inspection method
Tee joint
Vacuum pump
The number of random inspections shall be one thousandth of each batch of products, but shall not be less than 3.
During the inspection process, even if one valve does not meet one of the requirements of this standard, it will be extracted; when the test piece is re-tested, if there is still one unqualified item, the batch of products will be deemed unqualified. . 4.4 Type inspection
4.4.1 Under the following circumstances, the valve must undergo type inspection: a.
b.
c.
When there is a major change; when production is suspended for half a year and resumed;
when continuous production reaches one year.
4.4.2 Number and method of random inspection
Type inspection specimens shall be selected from the batches that have passed the factory inspection, and the number and judgment of the samples shall comply with 4.According to Article 3, testing rules, type inspection items and requirements can be found in Appendix A (Supplement). 674
JB/T6904
93
Appendix A
Type inspection items and requirements
(supplement)
A1 This appendix applies For the type inspection of various types of bottle valves, the inspection sequence, items and quantities are specified in Table A1. Table A1
test piece grouping
A
B
C|| tt||Additional instructions:
Test procedure
1
2
3
5
6
7| |tt||1
2
3
4
5
6
I
2||tt ||3
4
5
6
This standard is proposed by the National Valve Standardization Technical Committee. Test and inspection content
Article 3.1 appearance inspection
Article 3.2 inspection of connecting threads
Article 3.3 opening and closing torque inspection
Article 3.1 air tightness test
3.6 Strip temperature resistance test
3.10 strip vacuum test
3.7 strip pressure resistance test
3.1 strip appearance inspection
3.2 strip connecting thread inspection
3.3 opening and closing torque inspection
3.4 ??air tightness test
3.5 vibration resistance test
3.9 safety device action test
3.1 appearance inspection||tt ||3.2 connection thread inspection
3.3 opening and closing torque inspection
3.4 ??air tightness test
3.10 vacuum test
3.8 durability test| |tt||This standard is under the jurisdiction of Hefei General Machinery Research Institute of the Ministry of Machinery Industry. This standard was drafted by Shanghai Donghai Valve Factory and Hefei General Machinery Research Institute. The drafters of this standard are Cai Yanxin, Qian Faxiang, Zhu Xianting, and Zheng Qinglun. Number of random inspections
1~2
1~2
675
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