| 摘要 |
PROBLEM TO BE SOLVED: To improve an air vent device has the same action even if a check valve mechanism for communication/shut-off between a conduit and the inside of an inner case is removed at the lower part inside the inner case to simplify a construction, in the air vent device for conduit provided with an outer case part 1 formed at a high part halfway of the conduit and fixed to a large opening outlet, an inner case part 2 rotatably and tightly fitted in the outer case part and having a float part (upper/lower float bodies 4 and 5) arranged inside, a lid part 3 of the inner case part with a valve port, wherein a plurality of through holes are opened corresponding to the outer case part and the inner case part, positional relationship between the through hole of its own and that of the outer case part is changed by rotation of the inner case part so that the inside of the inner case part and the inside of conduit are made to communicate/shut off with/from each other, and the float part provided inside the inner case part opens/closes the valve port. SOLUTION: The through holes are arranged in at least two, upper and lower, stages (upper/lower through holes 13, 14, 25, and 26). At least the lower through hole is provided at the lower part of a rising float part. COPYRIGHT: (C)2005,JPO&NCIPI
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