Flow Sensor Thermal Time Constant Reduction via Opposite-Side Resistance Placement

The patent transitions from planar arrangement to three-dimensional overlapping arrangement. The flow-rate detection resistance element and temperature compensation resistance element are positioned on opposite faces of the insulation board, overlapping in the planar projection view. This spatial reconfiguration reduces the thermal path length between the elements while maintaining thermal isolation through the insulation board, thereby decreasing the thermal time constant and improving responsiveness without compromising temperature compensation accuracy.

The patent utilizes the thickness dimension of the insulation board to achieve thermal separation while maintaining close thermal coupling. By positioning the resistance elements on opposite faces of the board with overlapping projections, the thermal path is shortened through the insulation board thickness, reducing the thermal time constant. The insulation board's thermal properties in the thickness direction provide sufficient thermal separation for accurate temperature compensation.

The patent segments the sensor structure into distinct functional zones using the insulation board. The flow-rate detection resistance element is positioned on the front face exposed to fluid flow, while the temperature compensation resistance element is positioned on the back face, shielded from direct fluid contact. The overlapping arrangement maintains close thermal coupling for fast response, while the insulation board and structural design prevent fluid contamination of the compensation element.