| 主权项 |
1. A micro flow sensor, comprising:
a flow path through which a fluid to be measured flows; a detection unit having:
a heater configured to heat the fluid to be measured in the flow path, andtemperature sensors configured to measure a temperature of the fluid to be measured in the flow path; an arithmetic unit configured to measure a flow rate of the fluid to be measured flowing through the flow path based on the temperature of the fluid to be measured, measured by the temperature sensors; a narrowed portion disposed on an upstream side of the detection unit in the flow path for narrowing the flow path; and a first base plate and a second base plate connected to each other, the first base plate has first and second surfaces, the second surface being a connection surface connected with the second base plate, the second base plate has third and fourth surfaces, the third surface being a connection surface connected with the second surface, wherein: the narrowed portion is provided on an inlet for introducing the fluid to be measured into the flow path and includes a stepped portion formed on the third surface of the second base plate at a boundary between the flow path and the inlet, wherein the stepped portion defines an inner side wall of the second base plate, the inner side wall partially overlapping the inlet, the detection unit is disposed outside of the narrowed portion in the flow path, at least one of the base plates has a groove for defining the flow path, the first base plate has the inlet, the detection unit is disposed outside the second base plate to overlap the flow path, the first and second base plates each have a groove for defining the flow path, and a width Du of the groove in the second base plate and a width Dd of the groove in the first base plate satisfy a relationship of Du ≦Dd. |
