| CPC A47L 9/1683 (2013.01) [A47L 9/1608 (2013.01); A47L 9/165 (2013.01); A47L 9/1666 (2013.01); A47L 9/1691 (2013.01); B01D 45/16 (2013.01); B01D 50/20 (2022.01); B04C 3/06 (2013.01); B04C 9/00 (2013.01); B04C 2009/004 (2013.01)] | 15 Claims |

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1. Apparatus comprising
a vessel having a longitudinal axis and an annular cross section transverse to the longitudinal axis, said vessel having a first end and a second end, a tangential inlet near the first end, and an axial outlet at the first end, said second end being closed, said vessel being impervious except for the inlet and the outlet,
a vacuum actuated valve biased toward a closed position positioned to seal the inlet, and
a filter positioned in covering relationship with the outlet,
wherein the vessel is unopenable without being damaged.
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