Air filter assembly

1. A safety filter element comprising:

(a) a first wall of media extending between a closed end cap and an opposite open end cap, the first wall and end caps defining an interior volume, the open end cap defining a sealing structure having a first portion extending into the interior volume;

(b) an internal liner adjacent to the first wall of media and within the interior volume defined by the first wall of media; and

(c) an inset collar secured to the internal liner of the safety filter element at a location between the open and closed end caps and being entirely disposed within the interior volume adjacent to the open end cap.

2. The safety filter element of claim 1 , wherein the inset collar includes registration means for positively engaging an outlet tube of an air filter assembly.

3. The safety filter element of claim 1 , wherein the inset collar has a length less than a length of the first portion of the sealing structure.

4. The safety filter element of claim 1 , wherein the inset collar has a length equal to or greater than a length of the first portion of the sealing structure.

5. The safety filter element of claim 1 , wherein the inset collar extends into the interior volume towards the closed end cap further than the first portion of the sealing structure.

6. The safety filter element of claim 1 , wherein the inset collar has a generally constant internal diameter.

7. The safety filter element of claim 1 , wherein the inset collar is secured to the internal liner of the safety filter element at a location between the open and closed end caps.

8. A filter element comprising:

(a) a first wall of media extending between a closed end cap and an opposite open end cap, the first wall and end caps defining an interior volume having an inner diameter, the open end cap defining a sealing structure having a first portion extending axially towards the closed end cap into the interior volume a first distance; and

(b) an inset collar disposed within the open end cap of the filter element and being at least partially disposed within the interior volume such that the inset collar extends axially towards the closed end cap a second distance that is equal to or greater than the first distance, the inset collar being permanently coupled to the open end cap, wherein the inset collar has a maximum outer diameter less than or equal to the inner diameter.

9. The filter element according to claim 8 , wherein the sealing structure is molded onto the inset collar.

10. The filter element according to claim 9 , wherein the sealing structure is molded onto the first wall of media.

11. The filter element according to claim 8 , wherein the inset collar further comprises at least one protrusion extending radially outward from the inset collar, the at least one protrusion being configured to retain the sealing structure onto the inset collar.

12. The filter element according to claim 8 , wherein the inset collar further comprises a plurality of alignment ribs radially spaced around the inset collar.

13. The filter element according to claim 8 , wherein the inset collar further comprises a flange that engages with a second portion of the sealing structure facing away from the closed end cap.

14. An air filter assembly comprising:

(a) a housing having an interior volume defined by a sidewall extending between a first end, and a second end, the housing having an air inlet opening in the sidewall and an air outlet opening in the first end;

(b) a primary filter element operably installed within the housing interior volume, the primary filter element having an interior volume defined by a first wall extending between a closed end cap and an opposite open end cap;

(c) a secondary filter element operably installed within the primary filter interior volume, the secondary filter element having an interior volume defined by a first wall extending between a closed end cap and an opposite open end cap, the open end cap defining a sealing structure having a first portion extending axially towards the closed end cap into the interior volume a first distance;

(d) an outlet tube operably connected to the housing air outlet opening; and

(e) an inset collar disposed within and permanently attached to the open end cap of the secondary filter element and being at least partially disposed within the interior volume of the secondary filter element such that the inset collar extends axially towards the secondary filter element closed end cap a second distance.

15. The air filter assembly according to claim 14 , wherein the second distance is equal to or greater than the first distance.

16. The air filter assembly according to claim 14 , wherein the inset collar extends entirely over the sealing structure first portion from a first axial end of the first portion to a second axial end of the first portion.

17. The air filter assembly according to claim 14 , wherein the inset collar has a generally constant first internal diameter.

18. The air filter assembly according to claim 14 , further comprising a port configured to receive a sensing device.

19. The air filter assembly of any of according to claim 14 , wherein an interior surface of the inset collar is inset from an interior surface of the outlet tube.