US Patent 7383741 Flow rate-measuring apparatus

A flow rate-measuring apparatus comprises a housing having a passage for supplying a liquid thereto, and a pair of detecting sections provided at both ends of the housing, and which contain sonic wave transmitter/receiver sections capable of transmitting and receiving sonic wave signals. Cover members are installed on each of the detecting sections, wherein the cover members face the passage in the housing. Curved surfaces, which expand toward the passage, are provided respectively on ends of the cover members.