| 摘要 |
PROBLEM TO BE SOLVED: To provide a check valve capable of improving valve closing performance of a ball valve, and reducing the number of part items to reduce product cost. SOLUTION: A main body 2 of this check valve 1 is formed of synthetic resin, and a gap size between an inner wall 2e of a valve chest 2a and the ball valve 3 to be 0.06D-0.12D to an outer diameter size D of the ball valve 3 to reduce slide resistance between the inner wall 2e and the ball valve 3, reduce lateral movement of the ball valve 3 in the valve chest 2a, and require less time for its being seated onto a valve set 2c to prevent deterioration of valve closing performance. A downstream opening part of the valve chest 2a is contracted by thermal caulking to provide a diameter-contracted part 2d for supporting one end of a spring 4, thereby a retainer 15 (Fig. 3) can be dispensed with to reduce product cost. |
