Unit filter assembly

Claim 1

A UNIT FILTER ASSEMBLY COMPRISING: AN OPEN-ENDED FRAME MEMBER HAVING AN UPSTREAM DIRTY GAS INLET AND A DOWNSTREAM CLEAN GAS OUTLET; A FIRST SELF-SUSTAINING, DEFORMABLE, GAS PERVIOUS, LONGITUDINALLY EXTENDING, PLENUMFORMING WEB DISPOSED WITHIN SAID FRAME MEMBER IN CONTINUOUSLY PLEATED FASHION TO PROVIDE ADJACENT PLEATS OF GENERALLY U-SHAPED CROSS SECTION, EACH PLEAT HAVING A BASE PORTION EXTENDING A SMALL DISTANCE TRANSVERSELY ACROSS SAID DIRTY GAS INLET AND HAVING FLANK PORTIONS EXTENDING FROM SAID DIRTY GAS INLET TOWARD SAID CLEAN GAS OUTLET; A SECOND, SELF-SUSTAINING, DEFORMABLE, GAS PERVIOUS, LONGITUDINALLY EXTENDING, PLENUM-FORMING WEB DISPOSED WITHIN SAID FRAME MEMBER IN CONTINUOUSLY PLEATED FASHION TO PROVIDE ADJACENT PLEATS OF GENERALLY U-SHAPED CROSS SECTION, EACH PLEAT HAVING A BASE PORTION EXTENDING A SMALL DISTANCE TRANSVERSELY ACROSS SIDE CLEAN GAS OUTLET AND HAVING FLANK PORTIONS EXTENDING FROM SAID CLEAN GAS OUTLET TOWARD SAID DIRTY GAS INLET, SAID FLANK PORTIONS OF SAID PLEATS OF SAID FIRST AND SECOND WEBS BEING INCREMENTALLY FOLDED UPON THEMSELVES TO PROVIDE INWARDLY TURNED FLANGE MEMBERS OF SMALLER EXTENT THAN SAID BASE PORTIONS ENGAGING AGAINST FLANK PORTIONS OF PLEATS OF AN OPPOSITE WEB OF THE PLENUM-FORMING WEBS TO SPACE ADJACENT FLANK PORTIONS OF SAID FIRST AND SECOND WEBS AND FORM GAS PERVIOUS PLENUM CHAMBERS THEREBETWEEN; AND FORAMINOUS MATERIAL DISPOSED WITHIN SAID GAS PERVIOUS CHAMBERS IN SUFFICIENT QUANTITIES TO SUBSTANTIALLY FILL THE SAME.