| 摘要 |
<p>The chamber is constructed as a bellows, equipped with an actuating mechanism reciprocating along its longitudinal axis so as to increase and decrease the length and thus the volume of the chamber periodically. In a preferred arrangement (as shown), the actuating mechanism comprises a movable plate with central aperture, through which the material passes. The upstream side of the bellows is of smaller diameter than the downstream side. Press. fluctuations are produced without any direct contact of needles, pistons or similar mechanical moving parts with the material, thus reducing mechanical wear and minimising operating noise.</p> |
