| 摘要 |
PURPOSE:To prevent the positional slippage of a liquid level pipe and to prevent the occurrence of an false operation of a photocoupler, by engaging the liquid level pipe with an engaging element provided for a photocoupler cover. CONSTITUTION:A liquid vessel 2 accommodating a liquid W is provided, a transparent liquid level pipe 12 which can be seen from outside through a liquid level window cover 17 fitted to a liquid level window 16 of a case 3 is made to be continuous to the vessel 2, and the liquid W is introduced thereinto. A float 14 is made to float on the surface of this liquid W. Then, the float 14 is detected at a prescribed level of the liquid W in the pipe 12 by a photocoupler 26 fitted to a photocoupler cover 22 engaged with the cover 17, and an indicating operation is conducted. In this construction, said cover 22 is provided with an engaging element 27 for engaging the pipe 12, and thereby the pipe is positioned and supported for the cover 22. Therefore the optical axis of the photocoupler 26 coincides with the center of the pipe 12, i.e. the float 14, without fail, and thus a false operation of the photocoupler 26 is prevented from occurrence. |
