depressurize

1.Should a valve need repair, depressurize and drain the system on both sides of the valve.

如果一个阀门需要维修，则在阀门的两侧对系统进行减压和排放。

2.Always depressurize a regulator before closing the adjusting knob and removing the regulator from the cylinder.

在关闭调钮和从钢瓶上断开调前，总是使调减压。