| 摘要 |
PROBLEM TO BE SOLVED: To provide a float valve which can be used over the wide scope of pressure from low to high and causes no valve closing delay. SOLUTION: In this float valve, a casing with a valve chamber 3 inside is formed by a main body 1 including an entrance 4, an exist passage 5 and an exit 6, and a cover 2 connected to the main body 1. A first valve seat 8 on which a first valve hole 7 is opened, is formed on the lower side wall of the valve chamber 3. A second valve seat 10 is arranged at the exit 6 side of the first valve hole 7 possible to move freely. The second valve seat 10 has a second valve hole 9 which is smaller than the first valve hole 7 and closes the first valve hole 7 at a position tightly attached to the first valve seat 8. An entrance chamber 12 opened to the valve chamber 3 is formed at the back of the second valve seat 10. A shape memory alloy 13 in coil shape is arranged as a temperature responsible member. The shape memory alloy 13 contracts at low temperature in low pressure to open the second valve seat 10 from the first hole 7 and expands at high temperature in high pressure to close the second valve seat 10 to the first valve hole 7. A float 15 which opens and closes the first valve hole 7 when the second valve seat 10 opens the first valve hole 7, and opens and closes the second valve hole 9 which is smaller than the first valve hole 7 in diameter when the second valve seat 10 closes the first valve hole 7, is arranged in the valve chamber 3.
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