1 It is necessary to verify that the upstream and downstream pipelines of the valve have been relieved of pressure before disassembling.

2 Care must be taken to prevent damage to the sealing surface of parts, especially non-metal parts, when disassembling and reassembling.

3 The bolts on the flange must be tightened symmetrically, gradually and evenly during assembly.

4 Metal chips, fibers, grease (except those specified for use), dust, other impurities, foreign objects, etc., should not be allowed to contaminate, adhere or stay on the surface of the parts or enter the cavity during assembly.