| 摘要 |
PROBLEM TO BE SOLVED: To provide a mass flow rate sensor whose power consumption is small and whose characteristics and responsivity at start up are superior, and to provide a mass flowmeter using the sensor. SOLUTION: The mass flow rate sensor is provided with a semiconductor substrate 1, insulating layer 2, heaters 311, 312, resistance temperature sensors 321, 322 and protective layer 4. The heaters 311, 312 are formed on the surface of the insulating layer 2, and they are arranged and installed to be adjacent to the upstream part and the downstream part of a flow passage. Lower parts of the heaters 311, 312 are formed as a hollow 5 and are insulated thermally from other parts. The sensors 321, 322 are formed on the surface of the insulating layer 2 and are arranged on both sides of the heaters 311, 312, so as to become one row with respect to the flow passage. The mass flow rate sensor and the mass flowmeter, which uses the sensor can find the flow velocity and the direction of a fluid only by the heaters 311, 312 as active elements, and their response with respect to changes in the flow velocity can be made fast.
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