Respiratory flow sensor

A respiratory flow sensor comprising:

• a housing defining a flow space through which the respiratory flow flows;
• substantially identical first wire and second wire arranged at spaced locations from one another in said housing flow space;
• a power source for heating said first and second wires;
• an air resistance body arranged in a vicinity of said second wire;
• a measuring device;
• a third wire connected to said measuring device as a temperature-dependent electric resistor and arranged in said housing at a spaced location from said first wire and from said second wire, said third wire for determining the temperature of the respiratory flow with said measuring device;
• a central control and evaluating unit connected to the said power source and connected to said measuring device, said central control unit compensating a temperature change of the respiratory flow detected by said third wire based on a change in the heating current flowing through the said first and second wires to provide said first and second wires with an operating temperature that is above the temperature of the respiratory flow by a defined amount and said central control and evaluating unit determining an intensity and the direction of the respiratory flow flowing through said housing from the measured heating currents flowing through said first and second wires.