Thermal flow meter with reinforcing plate and method of manufacturing the same

A thermal flow meter comprising:

• a measurement tube made of resin including an inlet through which liquid enters and an outlet through which the liquid flowing from the inlet exits, and having an internal flow passage that extends along an axis and has a circular cross section from the inlet to the outlet;
• a temperature detecting substrate having a heating resistance element and a temperature detecting resistance element formed on a detection surface thereof along the axis;
• and
• a reinforcing place, wherein
• the detection surface of the temperature detecting substrate is bonded with an adhesive to the measurement tube along the axis, and the reinforcing plate is bonded with the adhesive to the measurement tube along the axis with the internal flow passage interposed between the reinforcing plate and the temperature detecting substrate,
• the measurement tube comprises an outer circumferential surface having a rectangular cross section comprising a first flat surface, the detection surface of the temperature detecting substrate is oppositely positioned relative to the first flat surface of the outer circumferential surface, and the rectangular cross section further comprises a second flat surface on which a face of the reinforcing plate is oppositely positioned with the internal flow passage interposed between the first flat surface and the second flat surface,
• the first flat surface and the detection surface of the temperature detecting substrate are bonded together with the adhesive, and the second flat surface and the face of the reinforcing plate are bonded together with the adhesive;
• the inlet of the measurement tube further comprises a circular cross section;
• and
• the internal flow passage positioned at the rectangular cross section of the measurement tube is offset from a cross sectional center of the measurement tube.