Active thermal isolation for temperature responsive sensors

An apparatus for monitoring airflow over a specified surface of a body comprising:

• a temperature responsive sensor located in the airflow over the specified surface of the body;.
• means for maintaining said temperature responsive sensor at a constant temperature;
• an active thermal isolator located between said temperature responsive sensor and the specified surface of the body, wherein said active thermal isolator comprises an upper layer facing said temperature responsive sensor and having a relatively high electrical resistance and a lower layer having a relatively high temperature coefficient of resistance;
• and
• means for controlling the temperature of said active thermal isolator to reduce conductive heat flow from said temperature responsive sensor to the body wherein said temperature controlling means controls the temperature of the lower layer of said active thermal isolator.

An apparatus for monitoring airflow over a specified surface of a body comprising:

• a temperature responsive sensor located in the airflow over the specified surface of the body, wherein said temperature responsive sensor is a hot wire anemometer comprising a sensing wire connected end-to-end between a support structure and an active thermal isolator comprising first and second wires in communication with said temperature controlling means, the first wire being wrapped around one end of the sensing wire and the second wire being wrapped around an opposite end of the sensing wire;
• means for maintaining said temperature responsive sensor at a constant temperature;
• said active thermal isolator located between said temperature responsive sensor and the specified surface of the body;
• and
• means for controlling the temperature of said active thermal isolator to reduce conductive heat flow from said temperature responsive sensor to the body.