CB 3021-1994 Safety valve technical requirements and performance test methods

CB 3021-1994 Safety valve technical requirements and performance test methods CB3021-1994 standard download decompression password: www.bzxz.net

Shipbuilding Industry Standard of the People's Republic of China
CB 3021--94
Safety Valve Technical Requirements and Performance Test Methods 1994-08-22 Issued
China State Shipbuilding Corporation
1995-05-01 Effective
1 Main Content and Scope of Application
Shipbuilding Industry Standard of the People's Republic of China
Safety Valve Technical Requirements and Performance Test Methods This standard specifies the technical requirements and performance test methods for safety valves. CB 3021-94
Classification Number; U5C
Code Name: CB3021-77
This standard applies to safety valves for pipelines and pressure vessels with a pressure of 0.1 to 25.0 MPa and a nominal diameter of not less than 10 mm, 2 Reference standards
GB569—65
GB2501—89
GB12241—89
GB12242—89
CB*56--B3
CB316—83
CB*821—84
CB*822-84
3 Technical requirements
Marine flange connection dimensions and sealing surfaces
Marine flange connection dimensions Wet sealing surfaces (four 3.1 Flange connection dimensions and sealing surfaces shall comply with the provisions of GB2501 and GB569. 3.2 Threaded connection dimensions shall comply with the provisions of CB*56, CB316 and CB°821, CB'822. 3.3 Springs
3. 3.1 Both ends of the spring shall have a supporting plane not less than or equal to three-quarters of the total area. The supporting end shall be tightly fitted to the working bed. The vertical deviation of the spring axis to the supporting planes at both ends shall not exceed 1.7mm for every 100mm length. 3.3.2 The spring index (ratio of median diameter to wire diameter) should be selected within the range of 4 to 10. 3.3.3 For springs without mandrels or working in sleeves, the ratio of free height to median diameter should not be greater than 3. 3.3.4 The deviation of the spring free height shall be in accordance with the provisions of Table 1. Table 1
Free height
>20~60
>60~120
3.3.5 The deviation of the inner diameter of the spring shall be in accordance with the provisions of Table 2. China Shipbuilding Industry Corporation 1994-08-22 approved >120~200
200300
450~600
1995--05-01 implementation
>20~40
CB 3021-94
The deviation of the free height of the spring shall be in accordance with the provisions of Table 3. 3. 3. 6
Working range
Height &
>~100
>100~150
10~12>12~15
±10%8
The spring shall be subjected to strong pressure treatment or heat strong pressure treatment. 10% (not less than two) of the springs with the same heat treatment temperature shall be taken to measure the permanent deformation or stiffness under the specified load. The deviation of the permanent deformation or stiffness shall not exceed 10% (the difference value of symmetrical or asymmetrical distribution may be specified according to the design requirements).
3. 4 Performance requirements
3. 4. 1 The opening pressure deviation shall meet the following requirements: Q
When the opening pressure is less than 0. 5MPa limit deviation, the opening pressure deviation is ±0. 014MPa: When the opening pressure is greater than or equal to 0. 5MPa, the opening pressure deviation is ±3% of the opening pressure. 3.4.2 The discharge pressure shall meet the following requirements:
The discharge pressure of the safety valve for steam shall not be greater than 103% of the opening pressure. The discharge pressure of the safety valve for air or other gases shall be less than or not exceed 110% of the opening pressure. The discharge pressure of the safety valve for water or other liquids shall be less than or not exceed 120% of the opening pressure. The opening and closing pressure difference shall meet the following requirements:
The opening and closing pressure difference of the safety valve for steam shall be in accordance with the provisions of Table 4. Table 4
Opening pressure
For pipeline use
or 20% opening pressure
The opening and closing pressure difference of air or other gas safety valves shall be in accordance with the provisions of Table 5, b.
Opening pressure
For pipeline use
15% opening pressure
The opening and closing pressure difference of water or other liquid safety valves shall be in accordance with the provisions of Table 6. Opening and closing valve
Opening and closing valve
Pressure vessel
10% opening pressurewwW.bzxz.Net
Opening pressure
Opening height shall comply with the following provisions:
CB 3021 94
Opening and closing valve
20% opening pressure
The opening height of the full-opening safety valve shall be greater than or equal to one-fourth of the flow channel diameter, and its deviation shall be ±5% of the average value! b. The opening height of the micro-opening safety valve shall be greater than or equal to one-twentieth or one-fortieth of the flow channel diameter. Before the medium pressure rises to the upper limit of the discharge pressure specified in this standard, the opening height shall reach the design specified value. 3.4.5 The valve action should be stable, without any jumping, bumping, or jamming. 3.4.6 The sealing test pressure should meet the following requirements: The sealing test pressure of the safety valve for steam is 90% of the opening pressure or the minimum value of the seat pressure, whichever is smaller. The sealing test pressure of the safety valve for air or other gases and water or other fluids is 0.03MPa lower than the opening pressure when the opening pressure is less than 0.3MPa. When the opening pressure is greater than or equal to 0.3MPa, it is 90% of the opening pressure. 3.4.7 The sealing test medium shall be in accordance with the requirements of Table 7. Table?
Safety channel for medium
Air or other gas
Water or other infectious agents
3.4.8 The sealing performance shall meet the following requirements:
Test with foreign substances
Flame and steam
Safety valve for steam. If there is no steam leakage at the outlet of the valve by visual or auditory inspection, the sealing performance is qualified. b.
Safety valve for air or other gas with metal sealing surface. The bubble filling per minute shall comply with the provisions of Table 8. a.
Flow channel diameter
Safety adjustment type
General safety limit
Air or other gas safety valve with non-metal sealing surface is not allowed to leak. 10.0
Working pressure MP
Maximum allowable leakage volume Gas-liquid number/ia
When the safety valve for water or other liquids maintains the pressure at the rated pressure for 2 minutes, there should be no water ball flowing on the sealing surface. 3.4.9 The displacement of the safety valve shall comply with the provisions of GB12241 or the national safety supervision case regulations. 4 Test method
4.1 The test medium fluid shall be clear and free of impurities. 4, 2 The test pressure gauge shall be calibrated and its accuracy shall not be lower than Class 1. The test pressure shall be within the range of one-third to two-thirds of the pressure gauge range, and the dial diameter shall be greater than or equal to 100mm4.3 The test shall meet the following requirements,
When testing with water or other liquid media, the air in the body shall be exhausted first, and the liquid remaining in the body cavity shall be removed in time after the test.
CB3021-94
b. The pressure gauge interface shall be close to the inlet end of the safety valve. The safety valve should be directly connected to a container that is large enough to open the valve for testing. c
4.4 Test items
4.4.1 Opening pressure test The test should be carried out according to the designed maximum and minimum opening pressures respectively, and the number of tests should be not less than two. It should be adjusted to the designed minimum opening pressure before leaving the factory. Or adjusted to the pressure specified in the order contract. 4.4.2 Displacement and displacement coefficient measurement according to GB12242. Body strength test requirements according to GB12241.
4, 4.4 Newly designed safety valves or safety valves of finalized design should be tested for the following items. a.
Body strength:
Sealing:
Opening pressure,
Discharge pressure or overpressure;
Return seat pressure or opening and closing pressure difference;
Opening height:
Model characteristics:
Drop plate or displacement system,
Performance test and displacement test methods are in accordance with GB12242, additional notes:
This standard is produced by the National Marine Machinery Standardization Technical Committee Equipment Parts Sub-Technical Committee: This standard is under the jurisdiction of the 63rd Institute of China Shipbuilding Industry Corporation. This standard was drafted by the 704th Institute and the 603rd Institute of China Shipbuilding Industry Corporation. The main drafters of this standard are Liu Jingcheng and Wu Shaozeng.
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