FILTER UNIT
A filter unit includes a body portion having a proximal end and a distal end. An engagement protrusion extends from the proximal end. The engagement protrusion includes a first portion that has a first radius of curvature and a second portion opposing the first portion that has a second radius of curvature that is larger than the first radius of curvature. A protruding retention surface is disposed on and extends radially outward from the body portion. The protruding retention surface is adapted to secure the filter unit in a filter head assembly.
1 . A filter unit comprising:
a body portion having a proximal end and a distal end;
an engagement protrusion extending from the proximal end, the engagement protrusion having a first portion that includes a first radius of curvature and a second portion opposing the first portion that includes a second radius of curvature that is larger than the first radius of curvature; and
a protruding retention surface disposed on and extending radially outward from the body portion, the protruding retention surface adapted to secure the filter unit in a filter head assembly.
2 . The filter unit of claim 1 , further comprising:
a first recessed retention surface disposed on the body portion, the first recessed retention surface adapted to secure the filter unit in the filter head assembly.
3 . The filter unit of claim 2 , further comprising:
a second recessed retention surface disposed on the body portion, the second recessed retention surface adapted to secure the filter unit in the filter head assembly.
4 . The filter unit of claim 3 , wherein the first recessed retention surface and the second recessed retention surface are on substantially opposing sides of the body portion.
5 . The filter unit of claim 1 , further comprising:
a central axis extending substantially centrally through the longitudinal extent of the filter unit, wherein a first plane is defined between the central axis and the first portion of the engagement protrusion and a second plane is defined between the central axis and the protruding retention surface, and wherein the angle between the first plane and the second plane is approximately 10 degrees.
6 . The filter unit of claim 1 , further comprising:
a central axis extending substantially centrally through the longitudinal extent of the filter unit, wherein a first plane is defined between the central axis and the first portion of the engagement protrusion and a second plane is defined between the central axis and the first recessed retention surface, and wherein the angle between the first plane and the second plane is approximately 26 degrees.
7 . The filter unit of claim 1 , wherein the distance from a top edge of the engagement protrusion to the protruding retention surface is approximately 41.2 millimeters.
8 . The filter unit of claim 2 , wherein the distance from a top edge of the engagement protrusion to the first recessed retention surface is approximately 62.8 millimeters.
9 . A filter unit comprising:
a substantially cylindrical body portion having a proximal end and a distal end;
an engagement protrusion extending from the proximal end of the cylindrical body portion;
first and second distinct retention surfaces disposed in the cylindrical body portion; and
a third distinct retention surface disposed on and extending radially outward from the cylindrical body portion.
10 . The filter unit of claim 9 , wherein the first and second distinct retention surfaces are defined by first and second grooves disposed in the cylindrical body portion.
11 . The filter unit of claim 9 , wherein the distance from a top edge of the engagement protrusion to the third retention surface is approximately 41.2 millimeters.
12 . The filter unit of claim 11 , wherein the distance from a top edge of the engagement protrusion to the first retention surface is approximately 62.8 millimeters.
13 . The filter unit of claim 10 , further comprising:
a central axis extending substantially centrally through the longitudinal extent of the filter unit; and
an outlet disposed on the engagement protrusion, wherein the central axis extends through the outlet.
14 . The filter unit of claim 9 , wherein the first and second distinct retention surfaces are disposed on substantially opposing sides of the cylindrical body portion.
15 . A filter unit comprising:
a body portion including an exterior wall and having a proximal end and a distal end;
an engagement protrusion extending from the proximal end, the engagement protrusion having a cross-section with only one axis of symmetry; and
a retention surface disposed on the body portion, the retention surface defined by one of:
a radially extending member that protrudes outwardly from the body portion; and
a groove defined in the exterior wall of the body portion.
16 . The filter unit of claim 15 , further comprising:
a central axis extending substantially centrally through the longitudinal extent of the filter unit, wherein a first plane is defined between the central axis and the first portion of the engagement protrusion and a second plane is defined between the central axis and the retention surface, and wherein the angle between the first plane and the second plane is approximately 10 degrees.
17 . The filter unit of claim 15 , further comprising:
a central axis extending substantially centrally through the longitudinal extent of the filter unit, wherein a first plane is defined between the central axis and the first portion of the engagement protrusion and a second plane is defined between the central axis and the retention surface, and wherein the angle between the first plane and the second plane is approximately 26 degrees.
18 . The filter unit of claim 15 , wherein the distance from a top edge of the engagement protrusion to a first gasket is approximately 2.7 millimeters.
19 . The filter unit of claim 18 , wherein the distance from the top edge of the engagement protrusion to a second gasket is approximately 18.7 millimeters.
20 . The filter unit of claim 18 , wherein the distance from the top edge of the engagement protrusion to the retention surface is approximately 41.2 millimeters.