Before the valve is installed, the model and specification should be checked according to the design requirements, and the correct installation direction of the valve should be determined according to the design drawings, the indication marks of the valve and the flow direction of the pipeline medium.For the valve waiting to be installed, the packing should be enrich, the gasket material should be correct, the gland bolt should have enough margin, and the temporary fixing device inside the valve should be removed. For valves installed in horizontal pipelines, the valve stem should be installed in the upper half of the circumference above the level of the pipeline. The handwheels of the valves on both sides of the safety valve should be easy to operate and can be installed inclined upward or horizontally. Flanged or threaded valves should be installed in the closed state; When welding valve, the valve should be in the closed state; For valves connected by socket welding, there should be a gap of 0.5-1.0mm at the socket end The welding seam connecting the butt welding valve and the pipeline shall be bottomed by hydrogen arc welding.If there is a welded valve on the pipeline with integral heat treatment, it should be welded after the overall heat treatment of the pipe section, and then the welding seam should be subjected to local heat treatment. The Angle between the valve transmission extension rod and the valve stem axis should not be more than 300, its joint should be firm and the rotation should be flexible. For valves with thermal displacement pipes, there should be free expansion and contraction gaps around the transmission rod. After the valve is installed, the operating mechanism and transmission should be debugged and tested to ensure reliable action, flexible start and correct indication.When installing cast iron, ferrosilicon and enamel lined valves, avoid strong connection or uneven force causing damage to the valve body.Double disc gate valves, through lift check valves, pressure relief valves and traps shall be installed in horizontal piping. The safety valve should be installed at the pipe end of the vertical pipeline, the inlet and outlet pipes must be fixed firmly, and the safety valve body must be vertical.Single gate valve and swing check valve should be installed on horizontal pipelines, and can also be installed on vertical pipelines or inclined pipelines.When carry and storing the valve, care should be taken to protect the handwheel from bumps and impacts. When hoisting the valve, it is strictly forbidden to tie the rope buckle on the handwheel or handle.Before installing the large valve, the load-bearing bracket should be pre-installed, and the weight of the valve should not be attached to the equipment or pipeline. The safety valve that needs to be finally adjusted on the pipeline system should be adjusted in time when the pipeline system is put into operation, and the adjustment requirements should comply with the safety valve adjustment of SH/T 3517-2001 (Petrochemical steel pipeline engineering construction technology standard) related regulations for safety valve adjustment. During the adjustment, the user and relevant departments should supervise and confirm on the spot, and lead seal safety valve and fill in the final adjustment record of the safety valve in time.
