Mitsubishi Denki Kabushiki Kaisha

Ryuji Toyama

Shinji Taniguchi

Koji Tanimoto

Tomoya Yamakawa

To provide a thermosensitive flow rate detecting in which no response lag occurs even if the flow rate change frequency is high, and no error in detection flow rate is produced even if the power source change would occur, a thermosensitive flow rate detecting device is provided which includes: a heat generating resistor provided in fluid to be measured for generating heat by electric power consumed in accordance with a flow rate of the fluid to be measured; a first temperature detecting resistor for detecting a temperature of the fluid to be measured which changes according to the flow rate; and a second temperature detecting resistor for detecting the temperature of said heat generating resistor, further including a bridge circuit provided with the first temperature detecting resistor and the second temperature detecting resistor, the heating current of the heat generating resistor being controlled such that a temperature difference between the first temperature detecting resistor and the second temperature detecting resistor is kept constant, and the flow rate within the fluid to be measured being detected by using the heating current, wherein a voltage in proportion to the heating current of the heat generating resistor is applied to the bridge circuit.

Thermosensitive flow rate detecting device

The invention provides a flow rate detector capable of precisely detecting a flow rate of an object fluid and effectively reducing a leaning error even when the object fluid is pulsating, thereby improving precision in detection of flow rate. The flow rate detector comprises a flow detector for outputting a flow-detecting signal Sf according to a flow rate of the object fluid utilizing heat transfer phenomenon from an exothermic resistor disposed in a fluid passage to the object fluid, and a gain compensator for compensating an error in a flow-detecting signal Sf by amplifying the flow-detecting signal Sf from the flow detector wherein the gain compensator is arranged to amplify the flow-detecting signal Sf by a substantially constant alternating current gain G larger than a direct current gain G at the time of zero frequency, in a frequency range higher than a frequency f A corresponding to the minimum pulsating frequency of the object fluid.

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Tokyo, Japan

Ryuji Toyama