Valve is in the fluid system, used to control the direction of fluid, pressure, flow of the device is to make piping and equipment medium (liquid, gas, powder) flow or stop and can control its flow device, valve is an important control component in fluid conveying system.
PREPARATION BEFORE OPERATION
Before operating the valve, read the operating instructions carefully. Before the operation must be clear about the flow of gas, should pay attention to check the valve opening and closing signs. Check the appearance of the valve to see if the valve is damp, if there is moisture to be dry treatment; if found other problems to be handled in a timely manner, not with failure to operate. If the electric valve is not used for more than 3 months, check the clutch before starting, make sure the handle is in the manual position, then check the insulation, steering and electrical wiring.
CORRECT OPERATION OF MANUAL VALVE
Manual valve is the most widely used valve, its handwheel or handle, is designed in accordance with ordinary human, taking into account the strength of the sealing surface, and the necessary closing force. Therefore can not use the long lever or the long board hand to board moves. Some people used to use the plate hand, should strictly pay attention to the opening of the valve should be strong smooth, avoid excessive force, resulting in the opening and closing of the valve, force should be stable, can not impact. Certain high-pressure Valve components that are opened and closed by impact have been considered such that the impact force can not be equal to the general valve.
When the valve is fully open, the handwheel should be reversed a little, so that tight between the threads, so as not to loose damage. For stem valves, remember the stem position at full open and full closed to avoid hitting the dead center at full open. And make it easy to check whether it is normal when it is completely closed. If the valve do off, or between the valve core seal embedded in a larger sundry, fully closed when the position of the valve stem to change. Damage to valve seal face or valve handwheel.
Valve opening: The groove on the top of the stem of the ball, butterfly, and plug valves is parallel to the channel, indicating that the valve is in full open position; when the stem is rotated 90 degrees left or right, the groove is perpendicular to the channel, indicating that the valve is in full closed position. Some Ball Valves, butterfly valves, plug valves to wrench and, channel parallel to open, vertical to close. Three-way, four-way valve operation should be open, closed, reverse signs. The handle should be removed after the operation.
CORRECT OPERATION METHOD OF SAFETY VALVE
The safety valve is tested and pressurized before installation. When the safety valve runs for a long time, the operator should pay attention to checking the safety valve. When checking, the person should avoid the exit of the safety valve, check the lead seal of the safety valve, pull up the safety valve with a wrench by hand, and open it once every once in a while Check the flexibility of the safety valve.
CORRECT OPERATION METHOD OF STEAM TRAP
Trap is easy to be water pollution and other debris blocked the valve. When enabled, first open the flushing valve, flushing pipe. If by-pass pipe is available, the by-pass Valve can be opened for temporary flushing. Drain Valve without flushing pipe and by-pass pipe. Remove the drain valve, open the cut-off flush valve, close the cut-off Valve, install the drain valve, then open the cut-off Valve and activate the drain valve.
CORRECT OPERATION OF PRESSURE REDUCING VALVE
Before opening the relief valve, open the by-pass Valve or the flushing valve, clean the dirt in the pipeline, after the pipeline is cleaned, close the by-pass valve and the flushing valve, then open the relief valve. Some steam pressure reducing valve before there is a steam trap, need to open first, then slightly open the pressure reducing valve after the cut-off Valve, finally put the cut-off Valve before the pressure reducing valve open, watch the pressure gauge before and after the pressure reducing valve, adjust the pressure reducing valve adjusting screw, after the valve pressure to a predetermined value, then slowly open the relief valve after the cut-off Valve, calibration valve after pressure, until satisfactory. Fix The adjusting screw and cover the protective cap.
If the relief valve failure or to repair, should first slowly open by-pass valve, at the same time close the valve before closing, manually roughly adjust by-pass valve, so that the pressure after the relief valve is basically stable at a predetermined value, then close the valve to replace or repair, and then return to normal.
CORRECT OPERATION OF CHECK VALVE
In order to avoid high impact force at the moment the check valve is closed, the valve must be closed quickly to prevent the formation of a large reverse flow velocity, which is the cause of the shock pressure when the valve is suddenly closed. Therefore, the closing speed of the valve should be correctly matched with the attenuation speed of the downstream medium.
If the velocity of the downstream medium varies widely, the minimum velocity is not sufficient to force the closure to come to a steady stop. In this case, the motion of the closing member can be suppressed by a damper within a certain range of its action stroke. The rapid vibration of the closure, will make the valve moving parts wear, wear too fast, leading to premature valve failure. If the medium is pulsating flow, the rapid vibration of the closure is also caused by extreme medium disturbance, where this is the case, the check valve should be located where the medium disturbance is minimal.
Post time: Jul-28-2021