2016年6月30日星期四

IOM For Gate, Globe & Check Valves

1-RECEPTION
1a- While unpacking the valve, confirm that the valves and any of the accessories were not damaged during transportation.
1b- Do not place the valve directly on the ground or concrete floor. Place the valve on wooden pallet for inspection.
1c- Do not remove the end caps or protective flange coverings until it is ready for inspection or installation. If the protective coverings are removed for inspection, immediately reinstall them after the inspection.
1d- It is strongly recommended that the valves are to be stored in indoor, in a dry, dust free atmosphere.
2-STORAGE
2a- Valve should be stored in a dry, weatherproof building (preferably climate controlled).
2b- The valve/its actuator should have all fluid ports or connections plugged to prevent ingress of water or dust. Coupling parts must be protected with grease or protective oil.
2c- Install plastic or plywood flange protectors on each flange. Tape the edges of the protector with dust-tape to provide an air tight seal.
2d- The product should be operated monthly to ensure lubricated areas have lubricant distributed accordingly. The valve stem should be left in a different position each month.
2e- Spray the inside of the valve to make it clean after installation.

3-INSTALLATION
3.1 Installation Positions
Cast Steel Wedge Gate valves are usually bi-directional, and therefore may be installed in either direction. In some special cases, gate valves may be unidirectional, in which case the direction of flow will be indicated on the valve body.
Globe and check valves are unidirectional, and have the direction of flow indicated on valve body. RELIA piston and ball check valves are recommended for use only in horizontal lines with the cover facing up.Spring loaded RELIA piston and ball check valves are recommended for use in horizontal lines only, but may be installed with cap facing down as well as up. RELIA swing check valves may be installed in horizontal lines or vertical lines where the direction of flow as indicated on valve body is upwards.
3.2 Installation Positions
Remove protective end caps or plugs, and inspect valve ends for damage to threads, socket weld bores or flange faces.
Thoroughly clean adjacent piping system to remove any foreign material that could cause damage to seating surfaces during valve operation.

Verify that the space available for installation is adequate to allow the valve (byvalve supplier )to be installed and be operated.

Caution: Insufficient clearance for the stem in the fully open position may cause the valve to be inoperable. Inadequate clearance for valves may add mechanical loading to the valve ends. Sufficient clearance should be allowed for threaded valves to be “swung” during installation.
3.3 End connections
3.3a- Threaded Ends
Check condition of threads on mating piping.
Apply joint compound to the male end of joint only. This will prevent compound from entering the valve flowpath.
3.3b- Flanged Ends
Check to see that companion flanges are dimensionally compatible with the flanges on the valve body and make sure sealing surfaces are free of dirt.
Install the proper studs and nuts for application and place the flange gasket between the flange facings.
Caution: Stud nuts should be tightened in a criss-cross pattern in equal increments to ensure proper gasket compression.
3.3c- Socket Weld Ends
Remove all grease, oil or paint from the pipe that is to be welded into the valve and from the valve end connections.
Insert the pipe into the valve end connection until it bottoms out in the socket weld bore. Withdraw the pipe 1/16” so that a gap remains between the pipe and the bottom of the socket weld bore to prevent cracks. Tack the pipe into the valve and complete the fillet weld.
Caution: Gate and globe valves should be lightly closed to prevent damage to the seating surfaces and stem caused by thermal expansion during the socket welding process.
3.3d Post-Installation Procedures
After installation, the line should be cleaned by flushing to remove any foreign material. When caustics are used to flush the line, additional flushing with clean water is required. The valve should be opened and closed after installation to ensure proper operation function.
With the line pressurized, check the valve end connections, body to bonnet/cover joints and stem packing area for leaks. The packing may have to be tightened to stop packing leakage at the system pressure.

4-OPERATION
Gate valves should be used only in the fully opened or fully closed position.
Globe valves should be used continuously at openings than 25%.
Caution: Gate and globe valves should not be left in the fully back seated position under normal operating conditions. The packing may dry out under these conditions and leak as the valve is closed.
A cool valve may leak through the gland when opened to hot fluid. Wait before tightening the packing as the problem may go away.
Metal seated check valves (piston, ball and swing) are not zero leak devices and may “seep” in service. This type of valve should always be backed up with an isolation valve (either gate or globe)
5-MAINTENANCE
Proper PPE should be worn when preparing to serve a valve. Observe the following general warnings.
-A valve is a pressurized device containing energized fluids and should be handled with appropriate care.
-Valve surface temperature may be dangerously too hot or too cold to the skin.
-Upon disassembly, attention should be paid to the possibility of releasing dangerous and or ignitable accumulated fluids.
-Adequate ventilation should be available for service.

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