How to replace the ball valve seat and seal

Ball valve seat and seal removal, the valve in a partially open position, flush and remove the body inside and outside the possible dangerous substances. Close the ball valve, pull down on both sides of the flange connection bolts and nuts, and completely removing the valve from the pipeline. Remove the drive - in a sequence Actuators, bracket, washer, stem nut, butterfly shrapnel, south, wear-resisting, stem packing. Remove the cover body connection bolts and nuts, separate the bonnet and valve body, and remove the valve cover gasket. Confirm the ball in the off position, it can be more easily from the body out, then remove the seat. In the valve body hole nudge stem until completely remove down, and then remove the o-rings and valve stem packing. Be careful when this operation, in order to avoid scratch stem stuffing-box seal surface and body parts. Reassemble the valve seat and seals: clean and check the removed parts, strongly recommend wrapped spare parts to replace the valve seat and valve cover gasket seal; According to remove the reverse order of assembly; Use specified torque, cross lock flange bolts; Use specified torque, locking stem nut; After installation of actuators, the corresponding input signal through the rotary valve rod drives the valve core to rotate, the valves to open and closed position.