Patent ID: 7854175

Claim:
A method for measuring flow velocity of a fluid flow, comprising: emitting electric charge carriers into the fluid flow from an emitter electrode, wherein the emitter electrode is under high voltage and touches the fluid flow at a first position, and wherein an emitter current flows through the emitter electrode; receiving a first portion of the emitted charge carriers by a sensor electrode which touches the fluid flow at a second position, wherein a sensor current flows through the sensor electrode, and wherein a second portion of the emitted charge carriers drains off via a counter electrode which is insulated from the emitter electrode; measuring the sensor current and the emitter current to provide a measured value of the sensor current and a measured value of the emitter current; and computing the flow velocity of the fluid flow from the ratio between the measured value of the sensor current and the measured value of the emitter current, the flow velocity of the fluid flow being computed according to a proportional relationship to the ratio between the measured value of the sensor current and the measured value of the emitter current.