| 摘要 |
PURPOSE:To prevent the freezing of a heat collector in winter by a method wherein when water in a water supply pipe leading to a tank is drained, water in the heat collector is drained automatically in response thereto. CONSTITUTION:When the freezing of a heat collector is expected, the water in a water supply pipe 2 is removed by closing a water supply valve 25 and by opening a supply water draining valve 26. When the water is drained from the water supply pipe 2, the pressure in a lower protective box 6 is released so that an upper bag 9 is subjected to a negative head pressure H shown in the drawing and the whole of water enclosed in the bag 9 is transferred to a lower bag 7 with the result that the bag 7 becomes somewhat swollen as shown by a thin dotted line while the upper bag 9 becomes fully collapsed as shown by a thin dotted line. Accordingly, no water load is applied on the bag 9 and so a transmission cable 14 gets loose due to the moment of load of a weight 13. Further, a water draining valve 19 of the heat collector is lowered to open due to its own weight and the pressure of the head of water filled in a water supply pipe 16 to which it is subjected so that the water in the heat collector is completely drained. |
