The present document describes a flow measuring apparatus for measuring the air flow through a section of an inhalation apparatus, and for measuring the drug delivery by inhalation using an inhalation apparatus. The flow measuring apparatus comprises a set of Pitot tubes configured for traversing entirely the lumen of the section of an inhalation apparatus. The set of Pitot tubes comprises a first and second Pitot tube which are respectively fluidly connected to a differential pressure sensor, for measuring a difference between a dynamic pressure and a static pressure within the flow measuring apparatus.
