Abstract: A composition ratio estimation device estimates a composition ratio of a content having mixed substances with different boiling points in a tank. The content is retained as a liquid in the tank lower part. The substances are partially floatable as a gas or liquid in a space in the tank upper part. The device includes a reference object disposed in the space, a transmitting-receiving unit that transmits radar waves toward the reference object and the surface of the liquid and receives reflected radar waves, a temperature measuring unit that acquires a level at which a boiling point of a floating substance is reached, a dielectric constant calculating unit that stores in advance a physical distance between the unit and the object and calculates a dielectric constant of a space between the unit and the object, and a composition ratio derivation unit that derives a composition ratio of the liquid.

Abstract: A high liquid-level alarm device is configured such that one casing includes a plurality of liquid-level alarm units, the liquid-level alarm units are directed for monitoring one liquid level, issue an alarm for a different height of the liquid level, have radio wave detection units for detecting a radio wave, respectively, each of the liquid-level alarm units has a radio wave detection unit for detecting a radio wave, transmits a radio wave when not detecting a radio wave, and performs a determination operation as to whether a predetermined liquid level is reached, and when one of the liquid-level alarm units is performing the determination operation, the rest of the liquid-level alarm units do not perform the determination operation.