The DN400 steam valve will not open
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The unit was shut down, and the large DN400 steam valve was closed. The unit remained shut down for several months; recently attempts were made to open that valve, but it wouldn’t open – even several people using two F-ratchets were unable to do so. It’s not clear what caused this issue Does anyone have any solutions? Thank you, experts, please share your ideas. Thanks
Possible reasons are as follows: 1. Rust inside the valve: Due to prolonged downtime, rust may have formed inside the valve, causing the valve core to stick to the valve seat. 2. Seal ring aging: The seal ring may harden or crack over time due to lack of use, resulting in difficulty in opening the valve. 3. Excessive torque on the control lever: After being unused for a long time, the control lever may experience an increase in the torque required to operate it due to rust or other factors. Solution: 1. Use a lubricant: Spray rust-preventing lubricant on the moving parts of the valve, especially the valve stem and threaded parts; allow it to penetrate for some time before attempting to operate it. 2. Use heat treatment: Gently heat the relevant parts of the valve to help loosen any stuck components. Be careful not to let the temperature get too high, to avoid damaging the valve components. 3. Use professional tools: If it still cannot be opened, it may be necessary to use specialized valve-opening tools or to enlist the help of professional technicians. 4. Replace parts: If the above methods still do not work, it may be necessary to replace some internal components of the valve, such as seals or valve cores. .
Replace our stem friction track gate valves to prevent this from happening!
After the vehicle has been warmed up and stopped, the thermal expansion and contraction of the internal components of the gate valve cause the gate to become wedged in place
What is the operating pressure of the pipeline? Will the valve not open before starting up and introducing air, or after that?
And what material are the valves and sealing surfaces made of?
It’s obvious that the valve is installed horizontally; the valve disc has shifted, and one side is pressing against the gate disc, resulting in an excessive pressure difference that prevents it from opening. You can try closing the upstream valve tightly; that should allow it to open.
Under pressure-free conditions, the insulation layer must be removed and the packing gland loosened; while operating to open the valve, strike the bottom of the valve body as well as the front and rear gate plates repeatedly
The valve plate is stuck too tightly. Remove the actuator, weld a 2mDN80 steel pipe to the shaft end, and use a chain hoist or jack to push it apart (pay attention to the direction)