Mitsubishi Denki Kabushiki Kaisha

Ryuji Tohyama

Naruki Suetake

Hiroyuki Uramachi

Shingo Hamada

Tomoya Yamakawa

Minoru Abe

Fumiyoshi Yonezawa

Takeharu Oshima

A flow rate-measuring device capable of measuring accurately a flow rate of fluid to be measured containing a drift or eddy as compared with a conventional device is provided. A flow rate-measuring passage for measuring a flow rate of the fluid to be measured is constructed so that its opening area in an upstream region communicating to an inlet gradually decreases from upstream to downstream. A flow rate-detecting element is disposed near an outlet in the flow rate-measuring passage The device is provided with a leak flow passage allowing a part of the fluid which has flown in from the inlet of the flow rate-measuring passage to leak out of the flow rate-measuring passage at a portion upstream from an outlet of the flow rate-measuring passage in particular upstream from a position where the flow rate-detecting element is disposed.

Flow rate-measuring device

A heat-sensitive type flow sensor which can be manufactured by using discrete parts at low cost in a miniature size with high accuracy and reliability includes a correcting circuitry capable of compensating for a detected current indicating a flow rate of a fluid of concern and outputted from a flow rate detecting circuit. In the heat-sensitive type flow sensor, an arithmetic processing circuit (,) for processing a detection voltage (V,) supplied from a flow rate detecting circuit (,) and indicating the flow rate includes a voltage-to-current conversion circuitry (,) for converting the detection voltage (V,) into a current (I,) and capable of performing gain adjustment, a correcting circuitry (,) for correcting a level of a current signal (I,) outputted from the voltage-to-current conversion circuit (,), and a detection current signal output circuit (,) for outputting the current signal (I,) corrected by the correcting circuitry (,) as a detection output current signal of the heat-sensitive type flow sensor. The correcting circuitry (,) includes diodes implemented as discrete parts which need not exhibit identical characteristic.

Heat-sensitive type flow sensor

A constant voltage circuit having excellent temperature characteristics at a wide temperature range. Temperature characteristics control means constructed by connecting a voltage dividing circuit formed by connecting fixed resistors in series to a diode in parallel is provided between a fixed resistor and a Zener diode having a positive temperature coefficient of a bridge circuit, and the output of a connection point between the fixed resistors of the temperature characteristics control means is applied to the non-inversion input terminal of a differential amplifier to correct the temperature change of the Zener diode.

Constant voltage circuit comprising temperature dependent elements and a differential amplifier

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Tokyo, Japan

Ryuji Tohyama