Flow meter with piezo-ceramic resistance element

摘要

A flow meter particularly for receiving respiratory flows for pulmonary function diagnoses has a perforated piezo-ceramic flow resistance element and transducer in a flow tube for providing a highly-sensitive flow measurement with little resistance to the flow. Electric contact plates abut opposite planar faces of the piezo-ceramic material plate and are spaced apart at the periphery of the piezo-ceramic plate by an insulating disk. Frame members carry the piezo-ceramic plate and electric contact plates and are spaced and protected within a housing of the flow meter by soft, floating seal members. Contact lugs connected to the electric contact plates conduct signals from the meter which are a function of the bending of the piezo-ceramic material plate under the differential flow pressures on an upstream and a downstream side of the piezo-ceramic plate.