Multistage air cleaner including pulse cleaning system

A filter mountable in and removable from an assembly, the filter comprising:

• (a) a closed frame structure and an open frame structure;
• (b) first and second filtration media panels mounted in extension between the closed frame structure and the open frame structure;
• (i) the first and second filtration media panels forming a V-shape with an angle of at least about 5 degrees;
• (ii) the first and second filtration media panels and the open frame structure defining an air flow aperture;
• (c) a seal arrangement circumscribing the air flow aperture and projecting outwardly from the open frame structure;
• and
• (d) a stop arrangement projecting outwardly from the open frame structure.

A filter assembly comprising:

• (a) a housing;
• (b) a retention mechanism within the housing, the retention mechanism having a locking member;
• and
• (c) a filter element positioned in the housing operably engaged with the retention mechanism, the filter element comprising:
• (i) a closed frame structure and an open frame structure;
• (ii) first and second filtration media panels mounted in extension between the closed frame structure and the open frame structure;
• (A) the first and second filtration media panels forming a V-shape with an angle of at least about 5 degrees;
• (B) the first and second filtration media panels and the open frame structure defining an air flow aperture;
• (iv) the closed frame structure defining a first receiver indent oriented between the first filtration media panel and the second filtration media panel;
• and
• (d) the locking member engaged with the first receiver indent.