| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a ball valve which can exert a self-closing function by a simple mechanism.SOLUTION: A ball valve attachment adds a self-closing function to a ball valve which comprises: a cylindrical valve main body having a flow passage for circulating a transportation fluid therein; a spherical valve body which is supported on the flow passage in the valve main body so as to be turnable, and in which a communication passage communicating to the flow passage is formed while penetrating therethrough; an operation member which is connected to the valve body, and turns the valve body in the valve main body; and a turn regulation protrusion which limits a turning range of the operation member so that the flow passage is brought into a closed state when being locked with a part of the operation member. The ball valve attachment comprises: a helical torsion coil spring which is directly or indirectly fixed to the valve main body at one end, and imparts a biasing force to the operation member so as to press a part of the operation member to the turn regulation protrusion; and a cover member which covers the helical torsion coil spring, is fixed with the other end of the helical torsion coil spring, and arranged so as to turn together with the operation member.</p> |
