Introduction of GB 12238-89 General Valve Flanges and Wafer Butterfly Valves
GB 12238-89 General Valve Flanges and Wafer Butterfly Valves is a Chinese National Standard for the connection of general valve and pipeline fittings, promulgated and implemented on March 1st, 1989. This standard sets the requirements, sizes, materials, technical conditions and test methods for the connection of general valve and pipe flange.
The scope of application of GB 12238-89 includes ordinary valves, pressure-containing valves, sealing valves and other pipeline connection valve fittings. But it does not involve temperature regulating valves, bellows valves and other special valves, threaded valve and flange which do not conform to the regulations of PN.1.6 MPa and the nominal diameter under DN100.
Requirements and sizes
For GB 12238-89 General Valve Flanges and Wafer Butterfly Valves, the requirements for the flange material in contact with the valve shall be the same as the flange material in contact with the piping system as stated in GB 1804. The nominal diameter, bore diameter and flange thickness shall meet the requirements of GB 14383.1. The pressure rating of flange shall meet the requirements of table 1 and table 2 in the standard.
The nominal size, system pressure, contact surface dimensions and wafer dimensions are set according to table 3 in the standard. The total height of the trimming parts of the butterfly valve, including the rubber packing is not greater than 50mm. The components in contact with the fluid, including valve body, disc, valve shaft, trim parts and fastening bolts shall be made of stainless steel, and other components shall be made of carbon steel or alloy steel.
Materials and Technical Conditions
For GB 12238-89 General Valve Flanges and Wafer Butterfly Valves, the materials of the valve body and valve disc is set according to the requirements of table 4 in the standard. The specific technical conditions for the butterfly valve which conforms to this standard are determined according to table 5. The opening and closing test pressure is determined according to table 6 and the sealing test, flow rate and torque test are determined according to table 6, table 7 and table 8 respectively.
Test Methods
The requirements for inspection and test of GB 12238-89 General Valve Flanges and Wafer Butterfly Valves are determined according to table 9 in the standard. The test methods are described in detail in the standard. On the basis of passing the test, the products should be given a test certificate.
Conclusion
GB 12238-89 General Valve Flanges and Wafer Butterfly Valves is mainly used in the connection of general valve and pipeline fitting. The standard specifies the requirements, sizes, materials, technical conditions and test methods for its application. It should be noted that the standard does not involve temperature regulating valves, bellows valves and other special valves, threaded valves and flanges which do not conform to the regulations of PN.1.6 MPa and the nominal diameter under DN100. It is necessary for users to refer to other national standards for these fittings.
