Cavitation in control valves
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The feed water valve on the steam drum has a pressure of 1.8 MPA on the upstream side and 0.8 MPA on the downstream side; it is a 1-inch single-seat valve that has been in use for 4 years. The valve body has become significantly thinner, and there are perforations; both the upper valve cover and the valve seat are heavily worn. Was this caused by the scouring effect of the deionized water on the upstream side, or by cavitation? What is the typical pressure difference at which cavitation occurs?
It must also be related to water temperature! Design several more water inlet pipes as a backup. Or add a heat exchanger to the pipeline.
A hissing sound is produced when cavitation occurs; once cavitation becomes stable, a grating noise is heard in the control valve, similar to the sound made by gravel flowing through it. You can observe and determine whether it is cavitation. I hope this helps you.
An anti-cavitation control valve can be replaced.
Overall, the material quality is poor; it’s better to replace the entire valve body. I’m not quite sure how cavitation can occur with hot water flowing through a system. A large pressure difference before and after the control valve often leads to flashing, or even cavitation. Isn’t cavitation only something that happens when gas is involved?
I personally agree with the judgment of the brother on the 5th floor
Could you tell me the temperature of the hot water? I’ll try to calculate it. It’s best to have some traffic. Is the valve core plunger-type or cage-type? The fluid velocity is highest at the throttling section of the valve body; vaporization occurs when the pressure at this location is below the saturated steam pressure. When the pressure behind the valve is above the saturated steam pressure, it is in a condition of cavitation ； When the pressure behind the valve is lower than the saturated vapor pressure, it is in a flashing condition.
Your demineralized water control valve is severely corroded – what about the other valves and pipelines?
I don’t know what material the valve body is made of; if it’s an alloy, it can be repaired using laser technology, and its surface can be treated to improve corrosion resistance. Of course, this treatment should be worth as much as the original material itself
It can’t be cavitation; it’s a situation where minor leaks from the valve seat gradually lead to the valve not closing properly. The valve seat is continuously eroded by these leaks, and both the valve body and the valve cover are also subject to erosion due to the high flow rates. The flow rate can be used to determine this. The 4-year period is likely the end of its service life; it should be replaced entirely to ensure safe production.
What material is this valve made of? It’s actually quite good; it’s been in use for four years, and the wear is likely due to erosion. If it’s a domestic valve, then this valve is quite good. If the inside of the valve body is surfaced welded at the time of manufacture, it should be able to last longer