Patent ID: 6729183
Filing Date: 2004-05-04
Classification: G01F

Abstract:
A thermosensitive flow rate detecting device comprising: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, provided in the fluid to be measured and positioned at a location that is substantially not in fluid communication with the heat generating resistor, for detecting a temperature of the fluid to be measured, wherein the fluid temperature changes in accordance with the flow rate; a second temperature detecting resistor, provided in fluid communication with the heat generating resistor, for detecting the temperature of said heat generating resistor, and a bridge circuit having said first temperature detecting resistor and said second temperature detecting resistor electrically connected together therein, the bridge circuit being adapted to control a heating current of said heat generating resistor to maintain a constant temperature difference between said first temperature detecting resistor and said second temperature detecting resistor, wherein the flow rate within the fluid to be measured is detected by using the heating current, and wherein said bridge circuit receives a voltage that is proportional to the heating current of said heat generating resistor.