Patent ID: 7823444

Claim:
A device for measuring the velocity of flow of a fluid in a respiration system having a fluid flow path, the device comprising: a first thermal sensor element; a controllable heating element associated with said first thermal sensor; a second thermal sensor element, said first thermal sensor element and said second thermal sensor element being arranged at spaced locations from one another at the fluid flow path of the respiration system, said first thermal sensor heating element generating a thermal signal, of a given duration, that is transmitted by the fluid flow along the fluid flow path from the first thermal sensor element to said second thermal sensor element and said second thermal sensor element detecting said thermal signal, of a given duration, from said fluid flow, and said second thermal sensor element being connected to said first thermal sensor element via a feedback connection such that each thermal signal, of a given duration, generated by said first thermal sensor element and detected by said second thermal sensor element brings about a return of a feedback pulse signal to said first thermal sensor element to cause said heating element of said first thermal sensor element to generate another thermal signal, of a given duration; and a controlling and analyzing means connected to said first thermal sensor element and said second thermal sensor element to start said generation of a first thermal signal, of a given duration, by said first thermal sensor element with a first pulse signal of a given duration determining a duration of the thermal signal and to read and analyze a signal frequency of said feedback pulse signals to determine the velocity of flow of the fluid during a further operation.