Filter assembly with an inner filter element with a top rib

1. A filter assembly, comprising:

an outer filter element comprising:

an outer filter media;

a first endplate disposed on a first end of the outer filter media, the first endplate defining a depression extending towards the outer filter media, the depression structured to retain a valve;

a second endplate disposed on a second end of the outer filter media opposite the first end;

a throat extending axially from the second endplate away from the outer filter media, a central axis of the throat being radially offset from a longitudinal axis of the filter assembly; and

at least one keying structure disposed on the second endplate and abutting an outside surface of the throat, the keying structure configured to engage a key feature of a housing within which the filter assembly is installed; and

an inner filter element disposed within the outer filter element, the inner filter element comprising:

an inner filter media; and

an inner first endplate coupled to a first end of the inner filter media proximate to the first endplate of the outer filter element, the inner first endplate comprising a circumferential rib extending from the inner first endplate towards the first endplate, the circumferential rib lacking flow passages therethrough along the axial length thereof from a top surface of the inner first endplate to a top portion of the circumferential rib furthest away from the top surface, the circumferential rib extending continuously in 360° around a portion of the top surface of the inner first endplate such that at least a portion of the circumferential rib is disposed circumferentially around the depression.

2. The filter assembly of claim 1 , wherein the keying structure comprises a tab positioned on a surface of the second endplate.

3. The filter assembly of claim 2 , wherein the tab extends radially from a base of the throat.

4. The filter assembly of claim 2 , wherein the tab comprises a rectangular protrusion.

5. The filter assembly of claim 1 , wherein the second endplate defines an opening, the throat extending from an inner circumferential surface of the opening.

6. The filter assembly of claim 1 , wherein the throat defines a groove on a radially outer surface thereof, and further comprising an O-ring disposed in the groove.

7. The filter assembly of claim 1 , wherein the second endplate comprises a skirt extending axially from the second endplate towards the outer filter media.

8. The filter assembly of claim 7 , wherein the skirt is not concentric with the throat.

9. The filter assembly of claim 7 , wherein an inner diameter of the skirt is larger than an inner diameter of the throat.

10. The filter assembly of claim 9 , wherein the second end plate comprises a flange extending between the skirt and the throat.

11. The filter assembly of claim 1 , wherein:

a central channel is defined and extends axially through the outer filter media, and the inner filter media disposed within the central channel.

12. The filter assembly of claim 11 , wherein the inner filter media is coupled to a media support structure disposed in the central channel.

13. The filter assembly of claim 12 , further comprising an inner second plate coupled to a second end of the inner filter media opposite the first end of the inner filter media.

14. The filter assembly of claim 1 , further comprising a center tube extending along the length of the outer filter media within an inner center area of the outer filter media.

15. The filter assembly of claim 14 , further comprising a wrap disposed within the inner center area and coupled to the center tube.

16. A method, comprising:

providing a housing for a filter assembly, the housing having a first portion and a second portion configured to be coupled to each other to define an inner volume for receiving the filter assembly, the second portion defining a key receiving feature;

providing a filter assembly, comprising:

an outer filter element comprising:

an outer filter media,

a first endplate disposed on a first end of the outer filter media, the first endplate defining a depression extending towards the outer filter media, the depression structured to retain a valve,

a second endplate disposed on a second end of the outer filter media opposite the first end,

a throat extending axially from the second endplate away from the outer filter media, a central axis of the throat being radially offset from a longitudinal axis of the filter assembly, and

at least one keying structure disposed on the second endplate and abutting an outside surface of the throat; and

an inner filter element disposed within a central channel of the outer filter element, the inner filter element comprising:

an inner filter media; and

an inner first endplate coupled to a first end of the inner filter media proximate to the first endplate of the outer filter element, the inner first endplate comprising a circumferential rib extending from the inner first endplate towards the first endplate, the circumferential rib lacking flow passages therethrough along the axial length thereof from a top surface of the inner first endplate to a top portion of the circumferential rib furthest away from the top surface, the circumferential rib extending continuously in 360° around a portion of the top surface of the inner first endplate such that at least a portion of the circumferential rib is disposed circumferentially around the depression; and

installing the filter assembly within the housing such that keying structure engages the key feature of the housing.

17. The method of claim 16 , wherein the keying structure comprises a tab positioned on a surface of the second endplate.

18. The method of claim 16 , wherein the tab extends radially from a base of the throat.

19. The method of claim 16 , wherein the second endplate defines an opening, the throat extending from an inner circumferential surface of the opening.

20. The method of claim 19 , wherein:

the second portion of the housing comprises a standpipe configured to be inserted through the opening into a central channel defined by the inner filter media when the filter assembly is installed in the housing.