| 摘要 |
<p>A first continuously operating extruder for an extrudable material is fed with filtered such material from a second extruder through a filter and a storage tank having means for applying pressure to the material in the tank. During replacement of a filter, the second extruder is stopped, and the flow of material out of the continuously operating extruder is maintained constant by blocking the passageway between the second extruder and the tank and by applying suitable pressure to the material in the tank until the filter is removed and replaced by a new filter. The blocking device may be separate from a holder for a pair of filters,both the blocking device and the holder being movable by a fluid operable piston and cylinder. Alternatively, a separate blocking device may be omitted, and the filter holder may carry a single filter and have an impermeable portion which provides the blocking function.</p> |
