Modular filter cassette

1. A filter assembly for filtering liquids, the filter assembly comprising: a filter housing having a filter inlet defining an inlet flow path and a filter outlet spaced from the filter inlet defining an outlet flow path, the filter housing defining a filter cavity comprising an upstream portion of the filter cavity in fluid communication with the inlet and a downstream portion of the filter cavity in fluid communication with the outlet;

said filter housing comprising a main shell, a side cover, a front end cover, and rear end cover that form the filter housing and the filter cavity in which a filter element is disposed;

a filter cover coupled to the filter housing to retain the filter element in place, said filter cover at least partially defining the filter cavity;

said main shell comprising bottom ribs, said bottom ribs have a tapered tip portion that is angled away from the filter cover from top to bottom to create a drain channel and said main shell comprising top ribs, said top ribs have a tapered tip portion that is angled away from filter cover from bottom to top to form a vent channel;

the filter cavity is at least partially defined by an upstream sidewall, a downstream sidewall spaced from the upstream sidewall, a third wall running from the upstream sidewall to the downstream sidewall, the filter inlet interfaces with the filter cavity at the third wall, and a fourth wall running from the upstream sidewall to the downstream sidewall and spaced from the third wall; and the filter element is shifted toward the upstream sidewall such that a distance between the filter element and the upstream sidewall decreases in a direction from the third wall to the fourth wall;

the filter element comprising a filter membrane to filter micron or submicron impurities from a process fluid disposed in the filter cavity, the filter element at least partially overlapping the filter inlet on a first side of the filter element, the filter element separating the upstream portion of the filter cavity from the downstream portion of the filter cavity, the filter element further comprising a potted rectangular pleated filter with a set of pleats having a first set of pleat tips on an upstream side of the filter element and a second set of pleat tips on a downstream side of the pleated filter, the sets of pleats packed together such that the first set of pleat tips form a generally planar rectangular entrance and the second set of pleat tips form a rectangular generally planar exit interface and wherein the primary flow path of the fluid through the filter element is perpendicular to the flow path through the filter inlet.

2. The filter assembly of claim 1 , further comprising a flow guide disposed between the inlet and the filter element, the flow guide configured to direct flow from the inlet to the upstream sidewall.

3. The filter assembly of claim 1 , further comprising a shifted parallelogram filter holding area, wherein the filter element is disposed in the shifted parallelogram filter element holding area.

4. The filter assembly of claim 1 , wherein the filter element comprises a first flap and a second flap and wherein the first flap and second flap are retained between the filter cover and the filter housing.

5. The filter assembly of claim 1 , further comprising symmetric main body portions.

6. The filter assembly of claim 1 , wherein the first set of pleat tips form a generally planer rectangular entrance interface with the upstream portion of the filter cavity and the second set of pleat tips form a generally planer rectangular exit interface with the downstream portion of the filter cavity.

7. The filter assembly of claim 1 , wherein the inlet interfaces with the filter cavity at the third wall and the outlet interfaces with the filter cavity at the fourth wall.

8. The filter assembly of claim 1 , wherein the upstream portion of the filter cavity is shaped such that the upstream portion of the filter cavity has a decreasing hydraulic diameter away from the filter inlet and the downstream portion of the filter cavity is shaped to have an increasing hydraulic diameter toward the outlet.

9. The filter assembly of claim 1 where main shell has end ribs, bottom ribs, top ribs, and intermediate ribs.

10. The filter assembly of claim 1 where the filter inlet overlaps the drain channel.

11. The filter assembly of claim 1 where a filter vent overlaps the vent channel.