US Patent 7100440 Flow meter

A compact and light flow meter having a rapid response includes a main body having a groove portion opened in the upper portion and also having connecting portions for communicating the groove portion and the exterior at both ends of the groove portion; a detachable cover body sealing the opened upper portion of the groove portion having a rectangular sectional shape in which a measured fluid is flowed; and a circuit substrate coming in close contact with the external face of the cover body. A sensor hole opened to the measuring chamber is arranged in the cover body; and a flow sensor is arranged in the circuit substrate so as to be arranged within the sensor hole and set a detecting face to face the measuring chamber.