| 摘要 |
<p>An improved ball valve (1), in particular for gas systems, includes a tampering indicating seal (25) made by injection molding a synthetic or metal material into cavities (19; 21; 22) formed in the screw-clamping nut assembly (11, 13) and including a cap outer portion (29) which substantially covers the surface of the outer face of the nut (13) and/or extending (29A) on the side surface of the nut (13).</p> |
