| 摘要 |
The device is based on a spirit level system where a bubble 6 is housed within a reservoir 7 of liquid. One side of the reservoir 7 acts to reflect light, from a source 2 disposed on a side of the reservoir remote therefrom, towards a pair of light sensors 1 and 3 disposed one each side of the source 2. Presence of the bubble 6 at a central zone of the reservoir increases reflectance of the light and the device detects a level condition when signals from both sensors 1, 3 are equal. <IMAGE> |
