1. Replace the cylinder outlet seal and valve cap. 替换钢瓶排气口密封和阀门帽。
2. Open vent needle valve and bleed air from hose. Then close vent valve. 开启排气针形阀，并从软管排放空气。然后关闭排气阀。
3. Adding air pressure within the annular space between the body and the sleeve can open, throttle, or close the valve. 在阀体和套管的环形空间内施加气压，就能够实现开启、节流或关闭阀门的功能。
英英解释
n.
1. a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through i
2. device in a brass wind instrument for varying the length of the air column to alter the pitch of a t
3. control consisting of a mechanical device for controlling the flow of a fluid
