| 摘要 |
PROBLEM TO BE SOLVED: To provide a showcase capable of measuring a distance between a water level sensor and a water level by eliminating the influence by wave even when the wave is generated on a water surface of drainage, and improving measurement accuracy by correctly measuring the distance, in detecting the full of drainage stored in a drainage receiver by using an ultrasonic sensor as the water level sensor. SOLUTION: In this showcase provided with the drainage receiver 4, and the ultrasonic sensor disposed at an upper part of the drainage receiver 4 as the water level sensor detecting a water receiving state of the drainage receiver 4, and measuring the distance between a water surface position of the drainage and the ultrasonic sensor, that is, the water level on the basis of a reflection time of ultrasonic wave emitted from the ultrasonic sensor, a water surface distance measuring range 10 for measuring the distance, is defined in a range outside of a passage of the wind passing through the upper part of the drainage receiver 4. COPYRIGHT: (C)2008,JPO&INPIT |
