Liquid filtration filter cap

1. A filter cap for attachment to an end of a filter having a central longitudinal passageway, the filter cap comprising:

a base adapted to cover the end of the filter, the base including a hole centered on a longitudinal axis;

a first projection extending from the base in a first axial direction along the longitudinal axis and adapted to be received in the central longitudinal passageway of the filter, the first projection defining a first projection passageway configured to communicate between the central longitudinal passageway and the hole in the base;

a second projection extending from the base in a second axial direction opposite the first axial direction and having a proximal end adjacent the base, a distal end spaced from the base and having an opening, at least one exterior peripheral groove to receive an o-ring, and a recess communicating between the hole in the base and the opening in the distal end; and

a plurality of radial ridges within the recess, each ridge having a bottom joined to the base, the ridge extending in the second direction from the base to an upper end within the recess and not extending into the first projection passageway, and a free end extending longitudinally between the upper end and the bottom of the ridge;

wherein a portion of the recess between the distal end and the upper ends of the plurality of radial ridges has a first transverse dimension, and a portion of the recess between the longitudinally-extending free ends of the radial ridges has a second transverse dimension that is smaller than the first transverse dimension.

2. The filter cap of claim 1 , wherein the first projection and second projection are both cylindrical.

3. The filter cap of claim 1 , wherein an annular recess is at least partially defined by the base and the first projection, the annular recess being adapted to receive the end of the filter.

4. The filter cap of claim 1 , wherein the first projection passageway has a transverse dimension smaller than the second transverse dimension.

5. The filter cap of claim 1 , further comprising a plurality of offset bumps on the base inside the recess, the offset bumps positioned between the ridges and the hole in the base.

6. A filter cap for a filter having a central longitudinal passage, the filter cap comprising:

a base;

a first cylindrical projection extending from the base in a first direction along a longitudinal axis, the first cylindrical projection including a solid cylindrical wall adapted to be received in the central longitudinal passage of the filter, the cylindrical wall having a first internal diameter;

a second cylindrical projection

extending from the base in a second direction along the longitudinal axis opposite the first direction,

extending a second projection distance from the base to a distal end of the second projection,

including a solid cylindrical wall having an external peripheral groove, and

having a second internal diameter larger than the first internal diameter;

an o-ring in the external peripheral groove;

a plurality of radial ridges extending radially inward from the solid cylindrical wall of the second cylindrical projection, the radial ridges being joined to the base and extending in the second direction from the base partway toward the distal end of the second cylindrical projection and not extending into the first projection; and

a passageway defined in the first and second cylindrical projections, the passageway having a first passage diameter in the first cylindrical projection equal to the first internal diameter, having a second passage diameter in the second cylindrical projection between the distal end and the radial ridges, the second passage diameter being equal to the second internal diameter, and having a third passage diameter in the second cylindrical projection larger than the first passage diameter but smaller than the second passage diameter, the portion of the passage having the third passage diameter being defined between ends of the radial ridges.

7. The filter cap of claim 6 , further comprising an annular recess between a portion of the base and the first projection, the annular recess being adapted to receive the end of the filter.

8. The filter cap of claim 6 , further comprising a plurality of offset bumps on the base inside the portion of the passageway having the third passage diameter, the offset bumps positioned between the ridges and extending in the second direction from the base.

9. A filter cap comprising:

a first end;

a first cylindrical projection projecting from the first end of the filter cap;

an annular recess around the first cylindrical projection;

a second end facing away from the first end;

a second cylindrical projection projecting from second end and including at least one peripheral grooves;

an O-ring received in the peripheral groove;

a passageway extending through the first and second projections, the passageway having in the second cylindrical projection a first transverse dimension and at least one second transverse dimension that is smaller than first transverse dimension and closer to the first projection than the portion having the first transverse dimension; and

a plurality of offset bumps on the second end of the filter cap and within the second transverse dimension.

10. The filter cap of claim 9 , further comprising a plurality of ridges extending radially inward within a portion of the second cylindrical projection to define second transverse dimension.

11. The filter cap of claim 9 , wherein the plurality of offset bumps are configured to abut a wall of a valve body and to provide a flow path between said wall and the second end of the filter cap to allow fluid flow from the portion of the passageway in the second projection into the portion of the passageway in the first projection.

12. The filter cap of claim 5 , wherein the plurality of offset bumps are configured to abut a wall of a valve body and to provide a flow path between said wall and the base to allow fluid flow between the first projection passageway and the opening in the distal end.

13. The filter cap of claim 8 , wherein the plurality of offset bumps are configured to abut a wall of a valve body and to provide a flow path between said wall and the base to allow fluid flow between the first projection passageway and the opening in the distal end.