The phenomenon where the gate valve cannot be closed
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I’d like to ask everyone! The drain valve (gate valve) of the unit’s evaporator sometimes gets stuck and cannot be closed after drainage is initiated! What are the reasons? Please give me some advice. Thank you everyone!
Sometimes the valve is opened too far, causing the valve disc to come off its track. Sometimes solid impurities get stuck,
The valve was not fully opened each time, and it is also possible that solid impurities got stuck in the screw.
The problems you mentioned generally occur in larger gate valves, those with a diameter of DN80 or more. This is because the lubrication in the copper sleeves is inadequate. There is an oil injection hole in the copper sleeve of the gate valve; use an oil gun to inject some butter into that hole, and after moving the valve a bit, things should get better. It’s important to take good care of the valve – not only by applying butter to the valve stem, but also to the copper sleeves, as that is even more crucial!
The air pressure is too low, the resistance of the valve stem packing is too high, the soft seal of the valve core is damaged, and impurities are stuck.
Something dirty is stuck in the valve passage; turning it on and off a few more times will fix it
The gate plate falling out of the correct position can sometimes also cause jamming