Industrial Valves will fail in predictable ways, and knowing what to look for to act in time to prevent a potential disaster will mean avoiding costly, unexpected down time.For more information see https://orseal.com/.
Leakage Past the Stem or Seat
Leakage past the stem or seat. Typically caused by worn or damaged packing glands, or a worn eroded seat. The packing will have hardened and crumbled, and will need to be taken down and replaced. The seat can be lapped to achieve a seal, or simply replaced with a new seat ring.
Valve Sticking or Seizing
If your valve becomes difficult to operate, or refuses to move at all, the fault may be due to corrosion or process deposits building up on the stem. The valve needs to be flushed and then operated slowly and under control until it moves again. Once freed the stem will need to be greased on a regular basis and the valve operated in and out of the open position in order to prevent further corrosion. A thread lubricant can be used on the stem.
Cavitation Damage
Cavitation is a situation where vapour bubbles are formed in liquid as a result of collapse of vapour bubbles against the internal surfaces of the valve. This causes pitting and erosion on the trim of the valve. This situation can be minimised by reviewing the pressure differential across the valve and selecting the appropriate trim for high pressure drop applications.
Incorrect Pressure Drop
An unexpected decrease in pressure can often be attributed to an undersized valve, blockage in the valve or incorrect location of the valve within the overall system. Refer to the valve design criteria for the size of the valve for the current process conditions. Also check for any blockage within the valve by stripping down the valve and checking for any debris or scale within the valve internals.
Corrosion and Material Degradation
It is important to note that Valve bodies and Trim are typically made of specific materials that can withstand process fluids. HSE guidance on safe isolation of plant and equipment must be followed before any inspection or repair work is carried out on live pressurised systems.
Identifying common faults with your valves before they fail and cause a shutdown to your plant will ensure your safe working and reduce unplanned downtime for you.
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