(1) MECHANICAL DRY-TYPE DUST ARRESTORS OR COLLECTORS OF THE VIBRATING POCKET TYPE USING AIR POROUS SHEET-LIKE FILTER MEDIA IN THE FORM OF CUT SHEETS OF FIBER GLASS, PAPER AND CLOTH, AND IN THE FORM OF PREFABRICATED POCKETS OF WOVEN GLASS AND CLOTH, (2) MECHANICAL VISCOUS TYPE DUST ARRESTORS OR COLLECTORS (A) OF THE PORTABLE UNIT OR CELL TYPE FOR USE IN KITCHEN RANGE HOODS, (B) OF THE TYPE USED TO CLEAN THE INTAKE AIR OF ENGINES AND COMPRESSORS AND (C) OF THE AUTOMOTIVE OIL BATH TYPE USED WITH INTERNAL COMBUSTION ENGINES AND HAVING A STATIONARY VISCOUS IMPINGEMENT FILTER MEDIUM AND A VISCOUS OIL BATH WHEREIN THE INCOMING AIR CARRIES OIL INTO THE FILTER MEDIUM FOR CLEANING AND COATING PURPOSES, (3) PORTABLE DUST ARRESTING UNITS OR CELLS HAVING A PERMANENT FRAME AND A VISCOUS IMPINGEMENT TYPE OF FILTER MEDIUM WITHOUT A VISCOUS COATING FOR USE IN PAINT SPRAY BOOTH AIR DISCHARGE OUTLETS, (4) MECHANICAL DRY-TYPE VENTILATING AIR FILTERS (A) OF THE PORTABLE DISPOSABLE TYPE WHEREIN THE ENTIRE AIR FILTER IS DISCARDED AFTER USE AND REPLACED BY A NEW FILTER INSTEAD OF BEING CLEANED, (B) OF THE PORTABLE CELL TYPE HAVING A REPLACEABLE FILTER MEDIUM, (C) OF THE FOLDABLE OR COLLAPSIBLE FRAME TYPE HAVING A REPLACEABLE FILTER MEDIUM, AND (D) OF THE STATIONARY POCKET TYPE HAVING A REPLACEABLE FILTER MEDIUM, (5) MECHANICAL VISCOUS-TYPE VENTILATING AIR FILTERS (A) OF THE DISPOSABLE TYPE WHEREIN THEENTIRE FILTER IS DISCARDED AFTER USE AND REPLACED INSTEAD OF BEING CLEANED, (B) OF THE REPLACEABLE MEDIUM TYPE HAVING A PERMANENT FRAME AND A TEMPORARY VISCOUS IMPINGEMENT FILTER MEDIUM WHICH IS DISCARDED AFTER USE AND REPLACED INSTEAD OF BEING CLEANED, (C) OF THE PORTABLE UNIT OR CELL TYPE HAVING A PERMANENT FRAME AND VISCOUS IMPINGEMENT FILTER MEDIUM, AND (D) OF THE AUTOMATIC SELF-CLEANING TYPE HAVING A MOVABLE VISCOUS IMPINGEMENT FILTER MEDIUM AND A STATIONARY VISCOUS LIQUID BATH FOR FILTER CLEANING AND RECOATING PURPOSES, (6) REPLACEMENT VISCOUS-IMPINGEMENT AIR FILTER PADS FOR VISCOUS-IMPINGEMENT VENTILATING AIR FILTERS OF THE REPLACEABLE MEDIUM TYPE, [ (7) MECHANICAL VISCOUS-TYPE UNITS FOR USE IN COMPRESSED AIR LINES, ] (8) MECHANICAL LOADERS FOR LOADING MECHANICAL DRY-TYPE VENTILATING AIR FILTERS WITH A REPLACEABLE SHEET-LIKE FILTER MEDIUM, AND (9) SPARE POCKETS AND VIBRATING MECHANISMS FOR ITEM 1, SPARE FILTER ELEMENTS FOR ITEM 2(B), SPARE CLEAN-OUT DOORS AND VALVES FOR ITEM 2(C), SPARE LATCHES FOR ITEM 4(B), SPARE POCKETS FOR ITEM 4(D), SPARE FILTER ELEMENTS FOR ITEM 5(B), SPARE FILTER PANELS, FILTER PANEL HOLDING CHAINS AND DRIVE LINKAGES FOR ITEM 5(D) [ AND SPARE FILTER ELEMENTS FOR ITEM 7 ]