Flow sensor

摘要

A flow meter has an elongate housing with a fluid inlet, a fluid outlet and an axial passage therebetween. The fluid passage contains a flow sensor assembly operationally connected in parallel to a flow splitter section. The flow sensor assembly has a flow tube forming an axial passage therethrough and the flow tube has a thermally diffusive sensor region. An upstream resistance thermometer and a downstream resistance thermometer are in thermal contact with the sensor region. The sensor region can additionally contain an electrically insulating coating on its outside surface and resistance thermometers formed by winding a single layer of a fine, uninsulated wire around its outside surface. The sensor assembly can be surrounded by inner and outer housings made of electrically and thermally conductive material connected to the flow tube near the ends of the sensor region and grounded to a printed circuit board.