Patent ID: 6748811
Filing Date: 2004-06-15
Classification: G01F

Abstract:
An ultrasonic flow meter, comprising: a measurement flow path through which a fluid to be measured flows; ultrasonic transducers provided respectively on an upstream side and a downstream side with respect to each other along the measurement flow path: an upstream aperture hole and a downstream aperture hole, the aperture holes for exposing the ultrasonic transducers to the measurement flow path; a first influent suppressor provided for the upstream aperture hole and the downstream aperture hole for reducing inflow of the fluid to be measured into the aperture holes; a second influent suppressor provided on an upstream side of the measurement flow path with respect to the aperture holes for reducing the inflow of the fluid to be measured into the aperture holes; a measurement control section for measuring a propagation time of an ultrasonic wave between the ultrasonic transducers; and a calculation section for calculating a flow rate based on a signal from the measurement control section, wherein the first influent suppressor provided for the aperture holes is an aperture hole sealing section having ultrasonically transmissive holes; and an aperture ratio of the aperture hole sealing section provided for the upstream aperture hole is greater than an aperture ratio of the aperture hole sealing section provided for the downstream aperture hole.