Valves installation procedure

Close the inlet and outlet stop valves and check that valve body is not under pressure. Remove nuts and lift packing flange and packing follower in sufficient height on the valve stem to apply the split packing around diameter of valve stem.

Lower packing follower over the new packing, lower packing flange and tighten sufficiently with nuts to stop leakage See Below Figure. During start-up some leakage may be observed. If pressure is raised considerably, the packing may leak slightly. For best results, it is recommended that after packing installation and adjustment the valve to be fully stroked approximately 20 times to break-in the packing and reduce stem friction.

Close inlet and outlet stop valve and relieve all pressure from piping involved. Loosen hex. Remove the lock nut holding the actuator to the bonnet and lift off the actuator. Remove actuator from valve body assembly as previously described in disassembly of diaphragm actuator from valve body assembly.

Remove bonnet hex. If necessary, remove seat ring by forcing a wooden dowel into seat bore and lifting. Clean all parts thoroughly. Polish stem with crocus cloth. It should be smooth and free of scratches especially in the packing area. Use approved non-residue forming solvent for cleaning.

Wipe dry with clean cloth. Inspect all parts and replace any excessively worn out or damaged part. Install a new graphite packing set as shown on packing installation sketch above Fig.

See previous section on renewing packing set. Seat ring must be correctly seated in place. Fix stud bolts to the valve body flange. Below procedure will be followed to ensure that no mistake is made at installation stage with regard to the correct selection, positioning and installation of all the control valves and actuators assembly.

When the correct valves , test points, vents and drain points have been identified for a specific control valve assembly. These will be tagged and stored ready for installation stage. The flange faces need to be free of dirt, grease, or any surface defects that may cause leakage. Also, the connecting pipeline should be free of any foreign materials, such as rust or welding slag that could damage the seat and disc sealing surface. Actuator s should be mounted on the valve prior to installation so the propper alignment can be made.

Make sure the valve, flanges, and pipe are all compatible with the correct pressure class and materials specified before installation. Check the flange bolts or studs for the correct size and length. The connecting equipment and lines should have the proper alignment prior to valve installation. When installing the valve and gasket s, the pipe should be spread apart just enough to allow the valve and gaskets without actually coming in contact with the flanges.