| 摘要 |
<p>The drinking trough has a water reserve which is maintained at a constant level by a tap and float (37,38). The trough is a hollow insulated container (10) with a sealed part (20) filled with warm air and an open part (30) filled with water to a level to a constant level from which the animals drink. The space (32), between the interior and exterior walls (33,34) of the water container, communicates with the warm air filled space so that the container at its sides and bottom is surrounded by warm air. An electrical heating device (21) is placed in a sealed air filled space.</p> |
