Abstract: A method of removing harmful gas is performed by a manner that a mixture of photocatalyzer and active carbon with air containing harmful gas and the mixture of photocatalyzer and active carbon are mixed in a chamber so as to drift the mixture in the air, the drifting mixture reacting with the harmful gas in illumination by lighting means, and the mixture catching said harmful gas so as to remove said harmful gas.

Abstract: An ultrasonic metering device having two ultrasonic transducers, each having an ultrasonic conversion element and a wedge for holding the conversion element, mounted on a pair of mounting members which are adapted to be mounted on a pipe in which a fluid to be measured flows. The mounting members clamp the pipe with first end portions of the mounting members being hingedly coupled to each other. Tightening means is provided for coupling opposite free end portions of the mounting members which have clamped the pipe to thereby fixedly secure the mounting members to the pipe.

Abstract: An ultrasonic measuring device for measuring the fluid flow of a high temperature fluid in a conduit. Ultrasonic transducers are mounted on first and second frames which have end portions hingedly coupled to one another. A tightening device at the other ends of the frames are used to secure the frames around the conduit carrying the fluid to be measured. Lead wires extend through hollow pipes between the ultrasonic transducers and connecting terminals at the outward ends thereof. Heat radiating fins may be provided at the outward ends of the pipes. With this construction, the outward ends of the pipes are at room temperature so that ordinary coaxial cables may be joined to the connecting terminals.