| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely seal a plastic tube in the penetrating part of a floor or a wall by surrounding a spring made of a shape memory alloy with a heat transmission delaying member for delaying the transmission of heat to the spring during the occurrence of fire. SOLUTION: A heat foamed refractory material 4 is foamed by 3 to 50 times when heated by the heat of fire and a fire resisting characteristic is maintained. An annular shape memory alloy spring 5 is made of, for instance a Ni-Ti alloy, subjected to a shape memory treatment so as to have an inner diameter sufficiently smaller than the outer diameter of a plastic tube 3 and buried in the heat foamed refractory material 4 while being extended by a normal temperature. As the result, the time of application of a contracting force by the shape memory alloy spring 5 is brought close to the time of the softening and melting of the plastic tube 3, the plastic tube 3 receives an expansion force by the foaming of the heat foamed refractory material 4 and the contracting force of the shape memory alloy spring 5 and fastened by a strong force. Thus, the plastic tube 3 is surely sealed.</p> |
