| 摘要 |
The device signals the freezing point in order to warn and inform subscribers on roads, motorways, bridges. A hollow chamber of glass or other solid material is partly filled with water in its lower part (1) widening upwards. A coloured liquid (2) is not miscible with water, lighter than water and with a freezing point lower plan the lowest temp. locally occurring, is placed on top of the water. The middle section (3) of the chamber has a large surface and thin, transparent walls. It forms the actual warning surface (5/5a). It connects with the top section (4) widening at the top. It serves as an expansion chamber, and has a hole at the top for filling the liquids, for their evacuation and sealing. When water freezes and expands, it pushes the light coloured liquid (2) from the middle section (3). |
