Flow measuring device

A flow measuring device comprising a housing in which a principal flow duct extends in which a pressure drop producing means producing a pressure drop in the medium flowing through is located and on whose duct wall the tapping openings of a plurality of tapping ducts connected with a flow ascertaining means arranged in or on the housing, are provided, wherein the principal flow duct, including the pressure drop producing means and the tapping openings, is a component of a sleeve-like duct insert inserted into a socket in the housing coaxially, the tapping ducts being composed of housing duct sections extending in the housing and opening at the inner face of the socket and of duct sections which extend in the wall of the duct insert and open at the outer face of the duct insert, the inner face of the socket and the outer face of the duct insert being designed as interfaces ensuring a correctly associated fluid link between the duct sections in the housing and in the insert.