Pumping apparatus

摘要

A conduit supplies a flow of gas to a sealed chamber surrounding the swept volume of a pump. The conduit comprises a flow impedance for limiting the rate of flow of the gas to the sealed chamber. Signals output from pressure transducers provided on either side of the flow impedance are used to detect leakage of gas from the sealed chamber into the pump swept volume, thus indicating the state of the seal surrounding the swept volume.