A turbine flow meter for imparting an angular momentum

摘要

A fluid flowmeter includes a turbine for imparting an angular momentum to a main flow of fluid related to a flow of fluid through the turbine. The flowmeter also includes an impeller for undergoing an angular deflection in response to the angular momentum of the main flow, which angular deflection is indicative of flowrate of the main flow. A poppet valve is provided for opening substantially as a function of pressure of the main flow to provide a bypass flow of fluid. The flow of fluid through the turbine is at most equal to the main flow reduced by the bypass flow. The valve is adapted such that the bypass flow varies so as to ensure that the flow through the turbine maintains substantially constant rotational speed of the turbine independent of flowrate of the main flow.