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Valve operation Caution

Valve used to attention
Valve installation is completed, the operator can control valves and actuators are familiar with the structure and performance, correctly identifying the direction of the valve opening, opening signs, signals, instructions, and can skillfully and accurately operate the valve, in a timely manner, decisively deal with various emergency breakdown. Valve operating correctly or not, directly affecting their life, and the equipment and installations related to the smooth, safe production.
Manual valve operation
Manual valve by handwheel, valve handle to operate in the petrochemical plant is common in applications, operators should note the following:
◆ valve opening direction, usually counterclockwise to open that valve, said valve clockwise closing. Therefore, pay attention to the direction switch valve
◆ valve handle, valve hand wheel size is based on the design of human switch. Therefore, if rotating valve manual switch can be realized, generally does not permit use of leverage or wrench to switch the valve. In order to prevent excessive force, damage to the sealing surface and other parts
◆ When the closed-type valve and the valve opening point to death, to turn 1 / 4 circle to 1 / 2 laps to thread a better seal, so as not to be overdone, damaged valves
◆ can not valve, throttle valve to do with, so easy to wash plates and valve sealing surface, and the introduction of vibration leakage, damage to the valve
◆ Open the steam valve should be slow to open, rule out the condensate pipe, preventing water hammer. Damage to the valve and pipe
◆ large diameter gate valve, globe valves and butterfly valves, some with bypass valve, whose role is to balance both sides of the pressure valve to reduce the opening force. So open, should open the bypass valve, slowly open the valve, closing valve should have closed the bypass valve, slowly close the main valve
◆ certain valve closed until the temperature drops, the valve contraction, due to minute leakage sealing surface, this time, the valve should be closed, a valve can close properly again
Automatic valve operation
◆ Trap
In operation, should discharge pipe in the dirt and impurities, prevent debris blockage, does not work. Operation, check the traps work, if too much steam discharge, indicating that the valve is not working properly, if only the discharge of water, indicating the valve is working properly
◆ valve
Safety valve set pressure should be regularly tested, and make constant pressure records and identification, installation, should go through a trial pressure, constant pressure test qualified. Safety valves are used in the past off-tuning, production units have a set of scientific management. In recent years, some units of the safety valve line calibration apparatus, which consists of mechanical, hydraulic and electronic records, whose advantage is that working conditions more in line with actual production data more realistic, and can not affect the production, without disassembly and handling, and improve the safety valve adjustment rate. Drawback is that only for spring safety valve,
And must have threaded stem; must know the average diameter of the valve sealing surface; safety valve can not be cleaned, ground, replacement parts and test for airtight. Such as the safety valve can not be returned after the jump seat Kai will be a lot of running, adversely affecting the production, should take immediate measures to deal with. The approach is hands stiffened and a wrench in the safety valve, to open a gap for some time, excretion of dirt, etc.
◆ valve
Before the opening of bypass valve or flush valve open pipeline cleaning, pipeline clean and close the bypass valve and then opening valve
The operation of other valves
With the other valve is electric, electromagnetic, pneumatic and hydraulic valves and other devices to open and close. By instrument, electric switch remote control. Therefore, operators should learn more about his move the valve structure and working principle, familiar with the operating rules, can operate independently than in the emergency treatment under accident conditions.
Note valve operation
◆ staggered to prevent the valve, the wrong pass, open drain, drain off. Operator to clearly understand the role of each valve and the location of the pipeline in the process, to prevent the misuse, they may have run materials, mixing, pressure-accident. If an oil refinery plant, before the start of steam purge, purge valve after the leak of a short sale related, results, start time, 370 ℃ high temperature slurry discharged from the emptying valve, causing the fire, the introduction of equipment downtime.
◆ low temperature below 0 ℃ season, out of the valve on to the main antifreeze, in a timely manner the end of a plug valve to open, pour it inside the water. Can not be excluded on the work of the valve and stopped the measures to be taken warm.
◆ valve working under high temperature, when the temperature rose to above 200 ℃ heat bolt elongation, easy to make the valve Mifengbuyan, necessary bolts should be "hot tight", hot tight, the valve should not be in full off position. So that the top stem death, and then turn difficult.
◆ valve leakage, leakage should first ascertain the location and cause, in general, two alternative for leakage and external leakage, external leakage into padding their external structure and the valve cover leak, valve leakage and the sealing surface or lining material leakage, the operator should be accurate to judge, he can be solved in time, can not solve the maintenance man in a timely manner to deal with.
◆ the weight of the valve packing gland should not be too tight to turn the stem flexibility is appropriate, the weight of too tight, will increase the valve stem friction, increased operating torque. Valve job, under normal circumstances can not just replace or add packing with pressure, or led to media leaks dangerous.

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