| 摘要 |
PURPOSE:To prevent freezing even when bathtub water is discharged inadvertently by providing a changeover valve using a shape memory alloy at an intermediate between a bathtub outgoing pipe and a return pipe. CONSTITUTION:A changeover valve 10 connected to the intermediate between a return pipe 3 and a bathtub outgoing pipe 2 constitutes a circulation circuit while bathtub water has a high temperature, and changes said circuit over to an enclosed circuit by short-circuiting the return pipe 3 and the enclosed circuit when the bathtub water has the temperature of unheated water. The changeover valve 10 has a rotary member 19 which changes over the circulation circuit and the enclosed circuit, and the shape memory alloy which rotates the rotary member. In the above described construction, when the temperature of water within the bathtub outgoing pipe 2 and the tool return pipe 3 is lowered, the shape memory alloy operates to automatically changes the circulation circuit to the enclosed circuit. Therefore, even when water within the bathtub 4 is discharged after bathing, water within the enclosed circuit is not discharged, and hence freezing can be prevented. |
