Abstract: A differential pressure flow sensor to measure the differential pressure in fluid flow in a pipe including an elongated pressure tube designed as an elongated hollow tube which is provided at its leading edge with at least one dynamic-pressure aperture and a sensor for the static pressure with at least one sensor aperture formed in the rear edge thereof. The sensor aperture being located in the wake of a body, either a separate body or a part of the hollow elongated tube, with front surfaces swept back from a forward tip and which are provided with detachment edges for the lateral detachment of the incident fluid flow without there being subsequent reattachment. In order to obtain the best test results from this differential pressure flow sensor, arcuate recesses are formed in the front surfaces at a distance from the outer limits for forming detachment edges for deflecting fluid from the planes of the front surfaces.