| 摘要 |
PURPOSE:To mitigate a water hammer by abruptly decreasing the receiving area of the counterflow pressure and slowly closing a valve body near the complete closure when closing a valve. CONSTITUTION:A valve body 11 has an annular wall 18 to be engaged with the side surface of an annular wall 16 when fully opened and is bored with multiple fluid guide holes 19 on the peripheral wall at a uniform distance in the circumferential direction, and a fluid passage 8 is formed in a liquid buffer chamber 21 normally communicated to the hollow interior of a guide section 7 via a small hole 20 provided on the peripheral wall of the guide section 7 near a step section 5. The buffer chamber 21 has the least volume under the fully closed state that the lug 14 of the valve body 11 is in contact with the opening end surface 15 of the guide section 7 and has the largest volume under the fully opened state that the annular wall 18 of the valve body 11 is engaged with a lug 22 provided on the side surface of the annular wall 16. Accordingly, when the valve body 11 nears the complete closure, the receiving area of the counterflow pressure is abruptly decreased to slowly close the valve body 11, and a waterhammer is mitigated. |
