Regulating valve technology of routine maintenance

In the soda ash production systems, increasing the degree of automation. The valve as an automatic control system actuators, has an important role in stabilizing the production, optimal control and so on. With a long-cycle, high-load operation, the control valve jam, corrosion, vibration, internal leakage and other problems continue to occur, resulting in shorter Gas Water Heater Valve regulating the life, work reduced reliability, seriously affecting the plant safe and stable operation. Therefore, the need for timely and accurately find and fix faults in the routine maintenance is very important, lists some common symptom and treatment methods. For reference only;

A regulating valve leakage
1, the drain valve stem length discomfort.
The reason valve leakage: gas open valve stem and valve stem is too short too long, stem up (or down) the distance is not enough, resulting in a gap between the plug and seat, not full contact, leading off lax internal leakage.
Solutions: should be shortened (or extended) valve stem to stem the appropriate length, it is no longer endoleaks.
2, packing filler leaked leaked reasons: after (1) Fill the stuffing is loaded into close contact with the stem, but this contact is not very uniform, some parts in contact with loose, tight contact with some parts, and even some parts did not contact on. (2) there is a relative movement between the stem and packing, as the impact of high temperature and pressure and permeability of the medium, resulting in packing leak. (3) the contact pressure is gradually attenuated filler, the filler itself and other reasons, the medium will leak out from the gap.
Solutions: (1) In order to facilitate the filler loading, chamfer at the top of the stuffing, the stuffing is placed at the bottom of the gap erosion resistant metal protective ring of small to prevent the filler is medium erosion. (2) packing box and packing contact surface should be smooth, reduce packing wear. (3) use of flexible graphite as a filler, which has good air tightness, low friction, small deformation, friction does not change after re-tightening and other characteristics.
3, the valve spool core seat deformation leak.
Spool valve leak valve production was mainly due to the process of casting or casting defects can lead to enhanced corrosion and erosion-corrosion medium through the fluid medium will give rise to the valve seat material erosion and impact, resulting in valve, valve seat deformation (or wear) is not complete, there are gaps, leaks.
Solutions: valve, valve seat corrosion-resistant materials. Worn deformation is not serious, can be used fine sandpaper grinding, eliminate traces improve the finish. If severe deformation, only replace the Gas Control Valve, the valve seat.
Second, the positioner fault locator is to use nozzle flapper technical principles, the general failure often occurs following:
1) Parts affected by temperature, vibration, resulting in mediation valve fluctuations.
2) The nozzle is clogged foreign material, the locator does not work.
3) The spring constant change, resulting in mediation valve control nonlinear.
4) electrical connector seal is not good, the rain will be positioned coil shorted or open circuit.
Solutions: The locator fixed firmly; sealed electrical connector; improving the quality of air purification, sewage drainage regularly.
Third, the valve action failure
1, the valve no action.
Cause: Insufficient supply pressure; actuator failure; valve no output signal; a foreign body in the gas safety burner valve; high-temperature parts trim stuck.
Solutions: Check the gas supply, restore pressure; good or bad, and the spring force of the spring to check whether the actuator diaphragm rupture and without damage (pneumatic valves); check signal; disintegration valve, a check for repairs.
2, the valve stroke inadequate Reason: Locator no improper calibration, stroke adjustment; actuator spring rating is too small; a foreign body within the valve.
Solutions: re-adjust the locator; adjust the spring; demolition valve remove the object.
3, the valve causes slow movement: packing too tight or packing deterioration of aging; the stem is not straight, misalignment, causing friction big; small air pressure.
Solutions: Recovery for the wind pressure; replace or repair the valve stem packing and other components.
Regulating valve maintenance and repair is a highly professional, technical extensive work involved. To do this work, not only need a solid theoretical foundation, but also has a wealth of practical experience, to take a scientific approach to improve the level of maintenance, reduce equipment failure rates, ensure plant safety, stability, long, full, excellent running to improve production efficiency and economic benefits.