Abstract: A flow rate measurement device is configured to measure a flow rate of a gas flowing inside of a pipeline, and includes an ultrasonic transducer installed so as to be in contact with the pipeline, and a flow rate calculation part configured to calculate the flow rate of the gas according to a result of reception of ultrasonic wave from the ultrasonic transducer, wherein the ultrasonic transducer includes an ultrasonic oscillation part configured to emit the ultrasonic wave toward the inside of the pipeline and an ultrasonic reception part configured to receive the ultrasonic wave, and at least the ultrasonic oscillation part has a focusing part configured to focus the ultrasonic wave on a center of the pipeline.

Abstract: A flow rate measurement device is configured to measure a flow rate of a gas flowing inside of a pipeline, and includes an ultrasonic transducer installed so as to be in contact with the pipeline, and a flow rate calculation part configured to calculate the flow rate of the gas according to a result of reception of ultrasonic wave from the ultrasonic transducer, wherein the ultrasonic transducer includes an ultrasonic oscillation part configured to emit the ultrasonic wave toward the inside of the pipeline and an ultrasonic reception part configured to receive the ultrasonic wave, and at least the ultrasonic oscillation part has a focusing part configured to focus the ultrasonic wave on a center of the pipeline.

Abstract: To reduce pressure loss on a heat-exchanger fluid while downsizing a heat exchange and reducing the production cost of the heat exchanger without impairment of the heat transfer performance of the heat exchanger by forming a fluid channel in surfaces of thin metal plates such as stainless steel plates through the use of an etching technique or the like and by improving the shape of the fluid channel. In a heat exchanger in which a plurality of heat exchanger fins are provided in thin metal plates by using an etching technique or the like and a fluid channel for a heat-exchanger fluid is formed between the two opposed thin metal plates by alternately stacking the thin metal plates, the area of the fluid channel, through which the fluid flows between the heat exchanger fins, is made substantially uniform by forming the heat exchanger fins so as to have a curved cross-sectional shape from the front end thereof to the rear end.

Abstract: To reduce pressure loss on a heat-exchanger fluid while downsizing a heat exchange and reducing the production cost of the heat exchanger without impairment of the heat transfer performance of the heat exchanger by forming a fluid channel in surfaces of thin metal plates such as stainless steel plates through the use of an etching technique or the like and by improving the shape of the fluid channel. In a heat exchanger in which a plurality of heat exchanger fins are provided in thin metal plates by using an etching technique or the like and a fluid channel for a heat-exchanger fluid is formed between the two opposed thin metal plates by alternately stacking the thin metal plates, the area of the fluid channel, through which the fluid flows between the heat exchanger fins, is made substantially uniform by forming the heat exchanger fins so as to have a curved cross-sectional shape from the front end thereof to the rear end.