Common fault and elimination
Whether regulator operate correctly has large relations with the maintenance works. The fault is varied, but a certain kind of fault emergence also may have different reasons.
一. actuator main fault components
Different types regulator and different parts have some key components, these components are also easy to fault components.
1. pneumatic, hydraulic actuators
a. Diaphragm To diaphragm type actuator, diaphragm is the most important element, under air source system normal circumstance, if actuators do not act, you should think of diaphragm rupture, whether is well installed. When the metal surface has cutting edges, burrs defects, which will bind the diaphragm, and diaphragm must be no leakage. In addition, the diaphragm use for a long time, material aging can also affect use.
b. piston pneumatic, hydraulic actuators piston produced driving force, therefore piston damage, wear is never allowed.
c. gas (liquid) tube is input pressure to actuator pathways, so often should check whether connect tightly, withnot leak.
d. Pushrod should check whether pushrod has bending, deformation, fall off. Pushrod connected with stem tightly, position needs to adjust well, so as to ensure sufficient stroke on-off valve.
e. spring should check whether spring has fracture. Manufacturing, processing and heat treatment inappropriate will make spring fracture. Some springs under overlarge load, also may rupture.
2. electric actuators
a. Motor check motor when can rotate, whether easy to overheat, whether have enough torque and bonding force.
b. servo amplifier check whether has output, whether can adjust.
c. decelerate actuator each manufacturer decelerate actuators are different. So need to check its transmission parts---shaft, gear, worm etc whether is damaged, whether wear is too big.
d. torque controller according to the concrete structure to check its failure reason.
二. valve main fault components
a. body should often check body inner wall corrosion and wear, especially the valves for corrosive medium and high pressure difference, cavitation effect bad process conditions, must ensure the compression strength and corrosion and abrasion resistance.
b. valve core because valve core acts as adjust and cutting fluid, is active component, so scour, corrosion by medium, particle collisions is most important, in high-pressure difference, cavitation cases is more easily damaged, so need to examine its various parts whether damage, wear and corrosion, whether need to repair or replacement.
c. seat seat jointing surface is the key to ensure valve close, its corruption and grinding are also serious. And because the medium penetration, makes fixed seat thread inside surface are often corrosion and loose, should be especially to check this part.
d. stem to check stem and core, whether pushrod connection loosen, whether produce too larger deformation, cracks and corrosion.
e. Packing check PTFE or other packing whether ageing, lack of oil, metamorphism, whether the packing is tight.
f. gaskets and o-rings these vulnerable parts can't crack damage, aging.
