| 摘要 |
PURPOSE:To detect an infiltrating liquid without suffering the effect of a state of transmitting no light and to detect the level of this liquid optically, by a construction wherein a lower end is opened and a dry part and a shaft part are provided above an inner cylinder wherein a sensor head is incorporated, while a sensor head supporting element is provided inside the cylinder. CONSTITUTION:A liquid level detecting sensor 21 is constructed in such a manner that a sensor head supporting element 18 having a sensor head 15 incorporated is inserted into an inner cylinder 1 kept in a prescribed humidity range so that light can be transmitted to a hollow part 20 of the inner cylinder 1, and that the inner cylinder 1 is covered with an outer cylinder 5 having liquid-passing holes 6 and 6'. As for a liquid 19 charging the inner and outer cylinders 1 and 2, a liquid having a larger specific gravity than a liquid to be detected, being hardly dissolved in the liquid to be detected and not being mixed therein and having a low melting point and a high boiling point, e.g. a fluoric inactive liquid, is used therefor, and the surface of the charging liquid is designed to rise above the lower end of the inner cylinder 1. Thereby the fore end of the sensor head 15 is kept from dew condensation or freezing due to the effect of water and from contamination or damage due to dust or the like. When the liquid to be detected infiltrates through the liquid-passing holes 6 and 6' of the outer cylinder 5 accordingly, the charged liquid 19 in the hollow part 20 inside the inner cylinder 1 rises higher than the level of the liquid to be detected, and when it reaches the fore end of the head 15, the level of the infiltrating liquid can be detected. |
