Internal leakage in the programmable control valves of Chengdu West China Hydraulics
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Our company uses Chengdu West China PSA technology and the hydraulic programmable valves provided by that company. When the outdoor temperature drops below -5°C in winter, leakage problems occur in these programmable valves, and a significant number of them develop such leakage issues. We are not sure as to the reason for this; generally, the sealing surfaces of these programmable valves need to be replaced every 2–3 years. I seek advice from experts.
Hydraulic programmable valve – this is not common. Is it a pneumatic programmable control valve instead?
I’m not sure what kind of valve you use; is it a disc valve? There might be two reasons for this. You mentioned that leakage occurs only at -5 degrees; well, one reason is that the gas contains water or other liquids that freeze at -5 degrees, resulting in solid deposits formed by the condensation of these liquids on the sealing surfaces ； Secondly, the sealing material of this type of valve causes internal leakage due to contraction at -5 degrees Celsius,,, But Huaxi should not make such a basic mistake; it’s unlikely that they would choose a sealing material that would have problems at -5 degrees Celsius,,,
http://bbs.hcbbs.com/thread-352976-1-1.html In the replies to that post, it is mentioned that at low temperatures the viscosity of hydraulic oil increases, which causes slower opening and closing; this seems to be related to your issue
It is recommended to switch to pneumatic! What is the gas treatment capacity? What is the pipe diameter? Now many manufacturers are switching to pneumatic systems. Don’t place faith in things like high torque or fast response times, etc.
Compared to hydraulic systems, pneumatic systems are cleaner and simpler, but they generate more noise. In low ambient temperatures, they also require a higher dew point for the instrument air (generally, the dew point of the instrument air should be at least 20 degrees lower than the ambient temperature; this requirement can be met in most chemical plants, as the flow of instrument air through solenoid valves causes throttling and expansion, which results in a drop in temperature). Hydraulic systems require a hydraulic station, and the oil circuits must also be cleaned thoroughly. The pressure is generally above 5 MPag; hydraulic oil becomes dirty when it leaks.