Valves precautions at work

Valve is an important thermal system components and valves operating personnel often have to deal with, so you must become familiar with and master the structure and performance of the valve, the valve correctly identify the direction of the opening flag indicating that the signal should be able to skillfully and accurately adjust and operate the valve promptly and decisively deal with various emergency failures. Operation, the main attention to the following categories:
1 Identify the valve switch direction. General manual valves, hand wheel clockwise direction indicates the direction of the valve is closed, the valve opening direction counterclockwise indicates, there are individual valves open and close the opposite direction and the operation should be checked before closing flag after the operation, plug stem top parallel grooves and channels, indicating the valve in the fully open position, the valve stem rotates 90 °, vertical grooves and channels, indicating the valve in the fully closed position, and some cock to wrench open the channel level behavior, the vertical is off. Three, four valve operation shall be open, closed commutation markers.
(2) force should be appropriate valve operation, the force is too big too fast easily damaged handles, hand wheels, stem and sealing surface abrasions, and even crush the sealing surface, do not use a large wrench to open and close a small valve to prevent excessive force large, damaged valves.
3 Turn on the steam valve, you must first pipeline preheating, excluding condensate, turned slowly turn to avoid water hammer phenomenon, damaged valves and equipment.
Larger diameter valves with bypass valve is open, you should open the bypass valve until the pressure reducing valve on both sides, and then open the large valve. Off, first turn off the bypass valve, and then close the large valve.
Gate valve, globe valve valve open head, to turn 1/4-1/2 turn is conducive to operation check, in order to avoid over-tighten, damaged valves.