Filter arrangement and methods

A filtration system comprising:

• (a) a tube sheet having at least a single through hole;
• (b) a sleeve member removably and replaceably mounted through said hole;
• (c) a flange fully circumscribing said sleeve member;
• (i) said flange extending radially from said sleeve member;
• (ii) said flange including first and second opposite axial surfaces;
• (d) a gasket member pressed between and against said first axial surface of said flange and said tube sheet to form a seal therebetween;
• and
• (e) a first filter element secured within said sleeve member and through said hole;
• said first filter element having opposite first and second ends;
• and a plurality of flutes;
• (i) each of said flutes having a first end portion adjacent to said first filter element first end, and a second end portion adjacent to said first filter element second end;
• (A) selected ones of said flutes being open at said first end portion and closed at said second end portion;
• and selected ones of said flutes being closed at said first end portion and open at said second end portion.

A method of servicing an air filtration system for a gas turbine system;

• the method comprising:
• (a) removing a pre-filter element from a sleeve member;
• the sleeve member being mounted through a hole in a tube sheet;
• and
• (b) replacing the pre-filter with a second pre-filter;
• the second pre-filter being a pleated panel;
• (c) fanning the pleated panel to form a circular, pleated pre-filter configured for straight-through flow;
• and
• (d) compressing ends of the pleats of the second pre-filter against an inner wall of the sleeve member.