| 摘要 |
<p>A vacuum seal comprises a pair of spaced die-holders, a pair or die-shaped elements located one in each die-holder and formed of a rigid material and having a parabolic form in axial section, a tube sealed between the die-holders and a removable insert of non-abrasive material having an opening therethrough and fitting closely within the tube. The seal enables lengths of uniform section material to be fed through a wall separating regions at different pressures e.g. for use in vacuum processing of rod, wire or strip. The die-shaped elements provide a severe restriction of the air flow and maintain the material passing through the elements in a central position through the insert. They also damp out vibrations caused by appts. moving the material through the seal.</p> |
