초록 ▼

Airflow measuring apparatus utilizes a temperature-varying resistance layer on a carrier as a sensor. The resistance and temperature of the temperature-varying resistance layer are maintained substantially constant by a regulator circuit, independent of the amount of cooling by air flowing past the

Airflow measuring apparatus utilizes a temperature-varying resistance layer on a carrier as a sensor. The resistance and temperature of the temperature-varying resistance layer are maintained substantially constant by a regulator circuit, independent of the amount of cooling by air flowing past the element. To minimize errors resulting from heating and cooling of the carrier, the surface of the carrier which does not have the temperature-varying resistance element is covered by a temperature-independent resistance layer and the current through the temperature independent resistance layer is controlled such that the temperature independent resistance layer is at substantially the same temperature as the temperature-varying resistance layer. Thus thermal gradients in the carrier are eliminated.

대표청구항 ▼

In airflow measuring apparatus having a support carrier (10, 10′) located in said airflow, a temperature-varying resistance sensor layer (12) on said carrier and supported thereby whereby the resistance sensor layer (12) will be in thermal transfer relation with respect to both said airflow and said

In airflow measuring apparatus having a support carrier (10, 10′) located in said airflow, a temperature-varying resistance sensor layer (12) on said carrier and supported thereby whereby the resistance sensor layer (12) will be in thermal transfer relation with respect to both said airflow and said carrier, and regulator means (16) for varying the current through said temperature-varying resistance sensor layer in such a manner that the temperature, and hence resistance of said temperature-varying resistance sensor layer remains substantially constant at a predetermined operating temperature, independent of the amount of airflow therealong, the improvement comprising a substantially temperature independent heating means (13) positioned in heat-conductive relation with respect to said support carrier (10, 10′) and electrically insulated from the temperature-varying resistance sensor layer (12) on said carrier to heat said carrier to a carrier temperature corresponding to said operating temperature, whereby errors in measurement resulting from heating and cooling of said carrier are substantially decreased.