The high pressure steam pipeline gate valve, valve packing at both sides of why there are two symmetrical small hole ah?
The water goes into the filling and fills the little hole, so that the gas in the pipe doesn't run out. It's a way to strengthen the sealing effect.
Water molecules are larger than gas, those two small holes, one water inlet, one water outlet.
Water gate valve is expensive, specially made, and did not use up, it is a waste. If not, just buy regular.