A machine where a static pressure rise is obtained by allowing successive volumes of gas to be aspirated into and exhausted out of a closed space by means of the displacement of a moving member. Disposable filter a filter element intended to be discarded and replaced after one service cycle. Drag Occurs when a valve does not close completely after popping and remains partly open until the pressure is further reduced. Drain valve A device designed to remove surplus liquid from the compressed air system. Manual units range from petcock to a ball, gate or globe valve.
Mechanical types consist of ball float.
Electrical drains include solenoid type that is energized by a timer signal, or electric motor driven units. Also pneumatically activated drains. Dripleg Is a pipe extending downward from the bottom of the airline to collect any condensation flow in the pipe. Drive A coupling between the compressor and the engine or motor. Dropleg Is a pipe coming from the top of the airline to feed air to an outlet for tools or air operated devices, so that condensation does not easily flow into the dropleg.