| 摘要 |
<p>The invention relates to a screw type valve comprising a valve shutter (11) with a base seal (15) and is axially movable in a control box from an open to a closed position through a rotating control stem. This stem (12), has an axial cavity (12a) which acts as a container for holding lubrificating grease; said shutter (11) has an axial through hole which has a first threaded part for connecting the control stem (12) and a second threaded part for receiving a screw (14) for fixing the base seal (15). <IMAGE></p> |
