JPS57208375A - Drain valve - Google Patents

Abstract

PURPOSE:To obtain the noiseless and positive operative drain valve by a method wherein a pair of shape memory alloys, one of which contracts and the other of which extends by heating, are fitted at the lower end of a shaft, at the tip of which a diaphragm for opening and closing the valve is provided, and said shaft is moved back and forth by means of heating. CONSTITUTION:The diaphragm 4 energized upward by a spring 5 at all times shuts-off between an influx port 2 and an exhaust port 3. The shaft 9, which is capable of piston motion and at the lower end of which the shape memory alloy 10 contracting by heating and the shape memory alloy 11 extending by heating are fitted as a pair through a sleeve 12, is fixed at the lower end of the diaphragm 4. When the valve is intended to open at this time, the heater 17 of the alloy 10 and the heater of a shape memory alloy 25 are energized. Because the alloy 25 is memorized so as to extend itself by heating, the alloy 25 lifts leaf springs 19 and 20, resulting in unfastening buttons 23 and 24 out of the holes 21 and 22 of the leaf springs 19 and 20 respectively. By the contraction of the alloy 10 simultaneous with the extension of the alloy 25, the shaft 9 is pulled down so as to separate the diaphragm 4 from the exhaust port 3 for draining.