| 摘要 |
PROBLEM TO BE SOLVED: To use a float type drain trap without retarding the closure of a valve over a wide pressure range from low to high pressure and to increase a draining capacity under high pressure. SOLUTION: A first valve seat 8 with a first valve port 7 open to the lower sidewall of a valve chest 3 is formed, and a second valve seat 10 having a second valve port 9 smaller in diameter than the first valve port 7 and restricting the area of passage through the valve port 7 is positioned on the outlet 6 side of the first valve port 7 in such a way as to be capable of moving back and forth. An inlet chamber 12 communicating with the back of the second valve seat 10 from the valve chest 3 is formed and a coiled shape memory alloy 13 serving as a temperature-reactive member is positioned therein. The shape memory alloy 13 contracts at low temperature, that is, at low pressure, and expands at high temperature, that is, at high pressure, so that the second valves seat 10 is deformed to increase or reduce the area of passage through the first valve port 7. A float 15 which opens and closes the first valve port 7 while the second valve seat 10 increases the area of passage through the first valve port 7 from the outlet 6, and which opens and closes the second valve port 9 while the second valve seat 10 reduces the area of passage, is positioned within the valve chest 3.
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