Patent Description:
Air streams can carry contaminant material therein. It is often desirable to filter these contaminants from the air stream before the air enters a particular system or operation, such as in the case of combustion air entering an engine in a motor vehicle or other power generation equipment.

In filtering systems where a replaceable filter element is inserted into a filter housing, sealing of the filter element within the filter housing is extremely important. In order to effectively filter out contaminants from the air stream as it passes through the filter element and the housing, the seal between the filter element and the housing should be airtight. If not, unfiltered air and dislodged contaminants can pass through gaps between the filter element and the filter housing and enter the system.

These types of filtering systems are known to create axial sealing forces when a gasket of the filter element is axially compressed under a clamping force created between a filter housing lid and a filter housing body in a closed position. It is desirable to improve upon the known unidirectional sealing forces to improve the overall sealing between the filter element and the filter housing, and thus improve the overall filtering effectiveness of the unit.

The following documents may provide useful technical background to the present disclosure: <CIT>, <CIT> and <CIT>.

The present invention provides a filter element and an air filter system as defined in the appended claims. At least one embodiment of the invention provides an air filter system, comprising a filter housing having a housing body with an inlet and an outlet in fluid communication. The filter housing has an annular seal surface extending radially outward from the housing body at the inlet of the housing body. The annular seal surface has an outer lip at an outer edge of the annular seal surface. The housing body also has a housing tooth extending from an inner edge of the annular seal surface axially outward in a direction substantially perpendicular to the annular seal surface.

The air filter system further comprises a filter element having a frame having an inlet panel and a slot. The inlet panel has an annular surface surrounding an inlet opening. The annular surface has exterior and interior edges. The slot is located through one side of the annular surface between the interior and exterior edges of the inlet panel. The filter element also has a gasket attached to the annular surface of the inlet panel. The gasket is formed such that the slot in the annular surface is uncovered, as well as the portion of the annular surface between the slot and the exterior edge of the annular surface. The gasket has a raised portion between the slot and the interior edge of the annular surface. The filter element is situated within the housing body such that the gasket seals against the annular seal surface of the housing body, and such that the housing tooth is disposed through the slot in the annular surface, wherein the interaction between the frame and the housing tooth provides a lateral bias of the housing tooth against the raised portion of the gasket.

In a further embodiment, a filter element is provided. The filter element is for use in a filter housing that has a first housing seal interface that surrounds a storage cavity. The filter element seals with the first housing seal interface to prevent dirty fluid or impurity bypass between the filter housing and the filter element. The filter element includes filter media, a frame and a gasket. The frame is attached to the filter media. The gasket is secured to the frame. The gasket includes a filter element seal interface that surrounds the filter media and is configured to mate with the first housing seal interface, the gasket including a first portion providing an axial seal surface forming part of the filter element seal interface and a second portion providing a radial seal surface forming part of the filter element seal interface.

In one embodiment, the frame is more rigid than the gasket.

In one embodiment, the gasket is an annular gasket. The first portion of the gasket has a greater radial dimension than the second portion of the gasket.

In one embodiment, the gasket has a radially outer periphery formed, at least in part, by the first and second portions. The second portion is stepped radially inward from the first portion forming a radial step in the radially outer periphery of the gasket.

In one embodiment, the axial seal surface of the first portion defines a first plane with the first portion being positioned axially on a first side of the first plane. At least a portion of the radial seal surface of the second portion is axially offset from the first plane and is positioned on a second side of the first plane, opposite the first side.

In one embodiment, a first portion of the frame that is adjacent the second portion of the gasket extends radially outward beyond the second portion of the gasket.

In one embodiment, the first portion of the frame includes a slot extending axially therethrough.

In one embodiment, the slot has a radially inner edge and a radially outer edge. The radial seal surface of the gasket is positioned radially at or radially outward of the radially inner edge of the slot.

In one embodiment, the filter element includes at least one end cap. The filter media includes a first face; a second face and a first end. The filter media extends axially between the first and second faces. The first end extends between the first and second faces. The first end cap secures to the first end. The first end cap is positioned radially between the second portion of the gasket and the first end of the filter media.

The gasket includes a third portion between the first portion and the second portion. This third portion may connect the first portion to the second portion. The first portion is angularly offset from the second portion. The first portion only provides an axially directed seal and the second portion only provides a radially directed seal. As such, at some angular positions of the gasket, only a radially directed seal is provided and at other angular positions only an axially directed seal is provided.

The third portion provides both an axially directed seal and a radially directed seal. The third portion allows from transitioning to relying on the axial seal to relying on the radial seal.

In one embodiment, the radial seal surface includes at least one groove formed therein. The groove extends longitudinally in an axial direction generally orthogonal to the axial seal surface.

In another embodiment, an air filter system including an air filter housing and a filter element as outlined above is provided. The filter housing includes a housing body and a housing tooth. The housing body includes a filter element storage cavity fluidly interposed between an inlet and an outlet. The housing body includes a seal surface defining a first housing sealing interface surrounding the filter element storage cavity. The first housing sealing interface includes a first portion including a radially outward extending axial seal surface for providing an axial seal. The filter housing seal interface includes a second portion including an axially extending radial seal surface facing radially into the filter element storage cavity for providing a radial seal. The housing tooth is adjacent the axially extending radial seal surface. The housing tooth is positioned on a first side of the axial seal surface and the radial seal surface, at least in part, is positioned on a second side of the axial seal surface, opposite the housing tooth. The filter element is removably installed within the housing. The first portion of the gasket of the filter element axially seals with the first portion of the first housing sealing interface. The second portion of the gasket radially seals with the second portion of the first housing sealing interface.

In one embodiment, the frame includes a radially extending flange including a radially directed abutment. The radially directed abutment is in radial abutment with the housing tooth radially biasing the frame towards the radial seal surface of the housing body when the filter element is received in the filter element storage cavity. The radial biasing of the frame by the housing tooth radially biasing the second portion of the filter element seal interface into the second portion of the housing seal interface.

In one embodiment, the frame includes a slot formed in the radially extending flange. The radially directed abutment defines a portion of the slot. The slot extends entirely through the radially extending flange along an axis that is generally parallel to a flow axis of fluid flowing through the filter element.

In one embodiment, the radially directed abutment radially faces the filter media of the filter element.

In one embodiment, the gasket is an annular gasket, the first portion of the gasket having a greater radial dimension than the second portion of the gasket.

In one embodiment, the gasket has a radially outer periphery formed, at least in part, by the first and second portions. The second portion is stepped radially inward from the first portion forming a radial step in the radially outer periphery of the gasket. The slot is angularly offset from the first portion of the gasket and is angularly aligned with the second portion of the gasket.

In one embodiment, the axial seal surface of the first portion of the first housing sealing interface defines a first plane. When installed, the first portion of the gasket is on a first side of the first plane. A portion of the radial seal surface of the second portion of the first housing sealing interface is axially offset from the first plane and is positioned on a second side of the first plane, opposite the first side.

In one embodiment, the first portion of the gasket is angularly offset from the second portion. The first portion of the gasket only provides an axially directed seal with the first portion of the housing seal interface and the second portion of the gasket only provides a radially directed seal with the second portion of the housing seal interface. As such, at some angular positions, only a radially directed seal is provided by the gasket and at other angular positions only an axially directed seal is provided by the gasket.

Embodiments of this invention will now be described in further detail with reference to the accompanying drawings, in which:.

<FIG> illustrates an air filter system <NUM> in an assembled configuration while <FIG> illustrates the air filter system <NUM> in an exploded configuration. The proposed air filter system <NUM> includes an air filter housing <NUM> and a filter element <NUM>. The filter element <NUM> is removable from the air filter housing <NUM> such that the filter element <NUM> can be removed and replaced as necessary.

The air filter housing <NUM> has a housing body <NUM> and a separate housing lid <NUM>. The housing body <NUM> and housing lid define ports <NUM>, <NUM>, which can be either inlets or outlets for dirty and clean air depending on the arrangement of the system. In this example, the port <NUM> of the housing lid <NUM> is the inlet into the system <NUM> and the port <NUM> of the housing body <NUM> is the outlet of the system <NUM>.

With reference to <FIG> and <FIG>, the housing body <NUM> has an inlet opening <NUM> that is in fluid communication with port <NUM>. At the inlet <NUM>, the housing body <NUM> has a seal surface <NUM> that defines a first housing sealing interface that surrounds a filter element storage cavity <NUM>. The first housing sealing interface includes a first portion <NUM> that includes a radially extending axial seal surface <NUM> as well as a second portion <NUM> that includes an axially extending radial seal surface <NUM> that faces radially into the filter element storage cavity <NUM>. The combination of the first and second portions combine such that the filter housing sealing interface extends entirely around the filter element storage cavity <NUM>.

In this example, the housing sealing interface and corresponding seal surfaces <NUM> and <NUM> extend around the entire periphery of the housing body such that the housing seal surface is generally annular. Notably, in this example, it is substantially rectangular and thus, annular will include non-round shapes.

The housing sealing interface and particularly the axial seal surface <NUM> may include, such as in the illustrated embodiment, a sealing bead <NUM> that extends outward from axial seal surface <NUM>. The sealing bead can facilitate sealing of a gasket <NUM>, which is operably sealing attached to filter element <NUM>, against the filter housing sealing interface.

In one example, axial seal surface <NUM> is generally planar except for sealing bead <NUM>.

The housing body <NUM> also has an outer lip <NUM> formed at the outer edge of the annular seal surface <NUM>. The outer lip <NUM> extends upward, substantially perpendicular to the annular seal surface <NUM>.

The housing body <NUM> also has a housing tooth <NUM>. The housing tooth <NUM> extends upward from the interior edge <NUM> of the annular seal surface <NUM>, substantially perpendicular to the annular seal surface <NUM>. In this example, the housing tooth <NUM> is positioned adjacent the second portion <NUM> that includes the axially extending radial seal surface <NUM>.

Thus, the housing tooth <NUM> is on a first side of the sealing surface <NUM>.

In some examples, the housing tooth <NUM> may extend above the outer lip <NUM> of the housing body <NUM> at the inlet <NUM>. The housing tooth <NUM> may have an oval, oblong, rectangular, trapezoidal, or any other shape desired. In some examples, the housing body <NUM> may have multiple housing teeth. In one example, such as illustrated in <FIG>, the housing body <NUM> is generally rectangular in cross-sectional shape and the housing tooth <NUM> is located along one of the short sides of the housing body <NUM>.

The filter element <NUM> is disposed within the housing body <NUM> and particularly within the filter element storage cavity <NUM> as illustrated in <FIG>. With reference to <FIG>, the filter element <NUM> has a frame <NUM> having an inlet panel <NUM>, two side flaps <NUM>, and a slot <NUM>. The inlet panel <NUM> is the initial point of entrance for unfiltered air entering the filter element <NUM>. The inlet panel <NUM> has an inlet opening <NUM> surrounded by an annular radially direct flange <NUM> that provides a surface <NUM>. Air can pass through the inlet opening <NUM>. The inlet panel <NUM> may have webbing <NUM> or support structures integrated within the inlet opening <NUM> to maintain the structural rigidity of the inlet panel <NUM>.

In one example, the frame <NUM> is more rigid than the gasket <NUM>. The frame could be formed from a rigid plastic while the gasket can be formed from a urethane or rubber material. The gasket can be molded to the frame or adhesively secured to the frame. In another example, the frame <NUM> and gasket <NUM> need not have different rigidities. However, the difference in rigidities allows the frame to transfer biasing forces to the gasket <NUM> while allowing the gasket <NUM> to be compliant and form seals with appropriate sealing surfaces of the housing body <NUM>.

The two side flaps <NUM> are attached in laterally spaced relation to the inlet panel <NUM> along opposite interior edges of the inlet panel <NUM>. The two side flaps <NUM> extend substantially perpendicular to the inlet panel <NUM>. The frame <NUM> is thus generally U-shaped. The inlet opening <NUM> is generally located between the pair of side flaps <NUM>.

The slot <NUM> is located through the radially directed flange <NUM> that provides annular surface <NUM> of the inlet panel <NUM> between the interior edge <NUM> and the exterior edge <NUM> of the radially directed flange <NUM> and annular surface <NUM>. When the filter element <NUM> is assembled into the housing body <NUM>, the housing tooth <NUM> is located through the slot <NUM> as illustrated in <FIG>. Because the slot <NUM> cooperates with the housing tooth <NUM> of the housing body <NUM>, it is desirable for the slot <NUM> to have a shape that compliments the shape of the housing tooth <NUM> and is capable of securely receiving the housing tooth <NUM>. When located through the slot <NUM>, the housing tooth <NUM> is surrounded by the inlet panel <NUM> at the inlet plane.

When installed in the housing body <NUM>, a portion <NUM> of the inlet panel <NUM> (see e.g. <FIG> and <FIG>) is located radially between the outer lip <NUM> of the housing body <NUM> and the outer surface <NUM> (see <FIG>) of the housing tooth <NUM>. This portion <NUM> is located proximate slot <NUM>. The portion <NUM> engages outer surface <NUM> of housing tooth <NUM>. The engagement with housing tooth <NUM> creates a lateral bias on the frame <NUM> and, consequently, filter element <NUM> in the direction illustrated by arrow <NUM> (see e.g. <FIG>) and thus towards the towards outer lip <NUM> as illustrated by arrow <NUM>. Consequently, this creates lateral bias on the housing tooth <NUM> that biases the tooth <NUM> inward and away from the outer lip <NUM>, as illustrated by arrow <NUM>.

As briefly mentioned, the filter element <NUM> further includes a gasket <NUM>. The gasket is attached to the annular surface <NUM> of the inlet panel <NUM>. The gasket entirely lines a perimeter edge of the annular surface <NUM>, except for the area over the slot <NUM> and the area of the annular surface <NUM> between the slot <NUM> and the outer edge of the annular surface.

As illustrated in <FIG>, a notch <NUM> is formed in the outer periphery of the gasket <NUM> to prevent the gasket <NUM> from sufficiently interfering with the housing tooth <NUM> during installation that prevents insertion of the housing tooth <NUM> through slot <NUM>. The notch <NUM> aligns with the slot <NUM> and receives the tooth <NUM> when the filter element <NUM> is installed. Due to the notch <NUM>, the radially outer periphery of gasket <NUM> has a radial step therein that accommodates the housing tooth <NUM> once installed.

In some examples, however, the gasket <NUM> may extend between the slot <NUM> and the outer edge <NUM> of the annular surface <NUM>, but not cover or completely cover the slot <NUM>.

With reference to <FIG>, in this example, the gasket <NUM> includes a first portion <NUM> that provides an axial seal surface <NUM> for sealing with axial seal surface <NUM>. The gasket <NUM> includes a second portion <NUM> that is adjacent slot <NUM> that provides a radial seal surface <NUM> for sealing with radial seal surface <NUM> (they are shown overlapped in <FIG> for illustrative purposes). In this embodiment, the second portion <NUM> is only located along one end of the rectangular shape of the gasket <NUM>. The first portion <NUM> of the gasket extends along at least a portion of all four side of the rectangular shape.

Further, the second portion <NUM> is located proximate the notch <NUM>. The notch is located between ends <NUM> (see <FIG>). Additionally slot <NUM> is positioned between ends <NUM>. As such, when viewed from the top, the slot <NUM> is generally angularly aligned with the second portion <NUM> and is angularly between the ends <NUM> of the first portion <NUM> of the gasket <NUM>. The axis about which these components are angularly aligned or offset would be an axis aligned with the flow of air through the filter element <NUM> (see axis <NUM> in <FIG>).

The gasket <NUM> includes third portions <NUM> that transition between the first and second portions <NUM>, <NUM>. In this example, the third portions <NUM> provide both an axial seal surface <NUM> and a radial seal surface <NUM>. As such, the third portions <NUM> seal with both the axial and radial seal surfaces <NUM>, <NUM> of the housing body <NUM>.

As such, when installed, only the first portion <NUM> provides an axially directed seal, the second portion <NUM> only provides a radially directed seal and the third portions provide both axial and radially directed seals.

The seal surfaces <NUM>, <NUM>, <NUM> and <NUM> of the first, second and third portions provide a filter element seal interface that fully seals with the housing seal interface provided by seal surfaces <NUM>, <NUM> of the housing body <NUM>.

In this example, the first portion <NUM> of the gasket <NUM> is positioned on one side of seal surface <NUM> while at least a portion of second portion <NUM> of the gasket is on the opposite side of seal surface <NUM>. As illustrated in <FIG>, the first portion <NUM> is above seal surface <NUM> while a portion of the second portion <NUM> is below seal surface <NUM>.

In one example, seal surface <NUM> of the housing seal interface is generally planar. However, in other embodiments, seal surface <NUM> and any cooperating seal surface of the gasket <NUM> can be non-planar.

In the illustrated example, when installed, the first portion <NUM> is located on one side of the plane defined by seal surface <NUM> and at least a portion of the second portion <NUM> is on the opposite side of the plane defined by the seal surface <NUM>. The first portion <NUM> of the gasket has a greater radial dimension D1 than the radial dimension D2 of the second portion <NUM> as illustrated in <FIG>. Again, this provides a radial step in the outer peripheral shape of gasket <NUM>. Further, the second portion <NUM> has a height H1 that is greater than the height H2 of the first portion <NUM>. Thus, there is an axial step between the bottom end of the second portion <NUM> and the seal surface <NUM>, which forms the bottom of the first portion <NUM>.

The second and third portions <NUM>, <NUM> extend outward and away from seal surface <NUM> of the first portion <NUM>.

With reference to <FIG>, the radially inner edge <NUM> of slot <NUM> may be radially inward of seal surface <NUM> of the second portion when in a relaxed state. As such, in some implementations, when tooth <NUM> is inserted through slot <NUM>, this further promotes compression of second portion <NUM> and sealing between the second portion <NUM> and the seal surface <NUM>. However, the radially outer edge <NUM> is laterally outward of seal surface <NUM>. Thus, seal surface <NUM> is located radially between edges <NUM>, <NUM> that bound, at least in part, slot <NUM>. In some embodiments, the inner edge <NUM> aligns with seal surface <NUM>. Thus, the seal surface <NUM> is typically positioned radially at or radially outward of the inner edge <NUM>.

In this example, edge <NUM> radially faces away from the filter media <NUM> while edge <NUM> faces filter media <NUM>. Further, flange <NUM> is axially offset from the inlet flow face <NUM> of the filter media <NUM>.

With reference to <FIG>, in some examples, seal surface <NUM> of the housing body <NUM> includes radially inward extending ribs <NUM>. The second portion <NUM> of gasket <NUM> may be sufficiently compliant to form around the ribs <NUM> when inserted or radially inward direct grooves <NUM> may be provided to help accommodate ribs <NUM>. Here grooves <NUM> extend longitudinally in an axial direction that is generally orthogonal to the axial seal surface <NUM> of the first portion <NUM>.

As noted above, the tooth <NUM> biases the filter element <NUM> and particularly frame <NUM> and gasket <NUM> radially and against seal surface <NUM>. This force can also help gasket <NUM> mate with or otherwise seal with seal surface <NUM>.

When the filter system <NUM> is assembled with the filter element <NUM> in the filter housing <NUM>, the gasket <NUM> seals with seal surfaces <NUM> and <NUM>. This may include sealing with sealing bead <NUM> as well as with annular lip <NUM>.

Notably, at the location of the housing tooth <NUM>, it has been discussed that the portion of the frame <NUM> between the annular lip <NUM> and the housing tooth <NUM> creates a lateral bias in the housing tooth <NUM>. This lateral bias of the housing tooth <NUM> compresses the second portion <NUM> of gasket <NUM> against the inner surface <NUM> of the housing tooth <NUM>. As a result, a lateral (also referred to as radial) sealing force is created between the filter housing body <NUM> and the filter element <NUM> and particularly gasket <NUM>. The lateral bias is generated by the engagement of outer edge <NUM> bounding slot <NUM> and outer surface <NUM> of tooth <NUM>. Outer edge <NUM> bounding slot <NUM> is thus an abutment against which tooth <NUM> applies pressure biasing the second portion <NUM> of the gasket <NUM> into sealing engagement with the second portion <NUM> of the housing seal interface of housing body <NUM>.

When the housing lid <NUM> is assembled with the housing body <NUM>, an axial sealing force is created between the filter housing <NUM> and the filter element <NUM> due to the compression of the gasket <NUM> between the housing lid <NUM> and the housing body <NUM> (i.e. the housing lid <NUM> acts on the frame <NUM> of the air filter element <NUM> creating a biasing force to compress the gasket <NUM> in a direction generally parallel to the clamping direction of the housing lid <NUM>). As used herein, generally parallel or generally perpendicular shall include deviations of up to <NUM> degrees.

The filter element <NUM> further includes an outlet grate <NUM> as illustrated in <FIG> and <FIG>. The outlet grate <NUM>, in one embodiment, has a base plate <NUM> and two side plates <NUM>. The two side plates <NUM> attach along opposite edges <NUM> of the base plate <NUM>.

With additional reference to <FIG>, the outlet grate <NUM> is sealed and attached to the side flaps <NUM> of the frame <NUM> of the filter element <NUM>. In particular, the side plates <NUM> are received between the laterally spaced apart side flaps <NUM>. The outer surfaces <NUM> of the side plates <NUM> of the outlet grate are adhesively attached (directly or indirectly) to the inner surfaces <NUM> of the side flaps <NUM> of the frame <NUM> such that the base plate <NUM> and the frame <NUM>, and particularly the inlet panel <NUM> thereof, are disposed at opposite ends of the filter element <NUM>. The base plate <NUM> and side plates <NUM> of the outlet grate <NUM> have a perforated structure, such as a honeycomb structure, to allow filtered, outlet air to exit the filter media <NUM> of the filter element <NUM>.

In some embodiments, when pleated media is used, portions of the media may extend around the side plates <NUM>, between the side plates and side flaps <NUM> and then around an outer surface of side flaps <NUM>. Adhesive may be used to secure the media in this configuration. The adhesive and filter media will also be used to promote operative sealing between the filter media <NUM> and the frame <NUM>.

With particular reference to <FIG>, the filter media <NUM>, which may be pleated filter media, is disposed, at least in part, between the frame <NUM> and the outlet grate <NUM>. The filter media <NUM> has opposed flow faces <NUM>, <NUM>. In the present example, folds forming the pleats of the filter media <NUM> extend in the long direction (e.g. parallel to axis <NUM> in <FIG>) and generally form flow faces <NUM>, <NUM>. The filter media <NUM> includes two end faces <NUM> that are not covered by the outlet grate <NUM> or frame <NUM>. In some examples, the outlet grate <NUM> is taped or otherwise adhesively attached to the filter media <NUM>.

The filter element <NUM> also has two end caps <NUM> potted to the frame <NUM>, outlet grate <NUM> and filter media <NUM>. Each end cap <NUM> seals against an associated one of the end faces <NUM> of the filter media <NUM>. The end caps <NUM> and potting material (if present) seal the pleated ends of the filter media <NUM>. In this example, the end caps <NUM> are cup shaped. Each end cap <NUM> receives an end of each side flap <NUM>, an end of the outlet grate <NUM>, and an end of the filter media <NUM>. As illustrated in <FIG>, one of the end caps is generally located between the filter media <NUM> and the second portion <NUM> of the gasket <NUM>.

In some examples, the filter element <NUM> is generally parallelogram shaped, in which case the gasket plane (e.g. seal surface <NUM> is parallel to the inlet and outlet flow faces of the filter element <NUM> and particularly the inlet and outlet flow faces of the filter media <NUM>.

Claim 1:
A filter element (<NUM>) for use in a filter housing (<NUM>) having a first housing seal interface that surrounds a storage cavity (<NUM>), the filter element (<NUM>) comprising:
filter media (<NUM>);
a frame (<NUM>) attached to the media; and
a gasket (<NUM>) secured to the frame (<NUM>), the frame (<NUM>) being more rigid than the gasket (<NUM>), the gasket including a filter element seal interface (<NUM>, <NUM>, <NUM>, <NUM>) that surrounds the filter media (<NUM>) and is configured to mate with the first housing seal interface,
characterized in that:
the gasket (<NUM>) includes a first portion (<NUM>) providing an axial seal surface (<NUM>) forming part of the filter element seal interface and a second portion (<NUM>) providing a radial seal surface (<NUM>) forming part of the filter element seal interface,
wherein:
the gasket (<NUM>) includes a third portion (<NUM>) between the first portion (<NUM>) and the second portion (<NUM>);
the first portion (<NUM>) is angularly offset from the second portion (<NUM>);
the first portion (<NUM>) only provides an axially directed seal and the second portion (<NUM>) only provides a radially directed seal, such that at some angular positions only a radially directed seal is provided and at other angular positions only an axially directed seal is provided; and
the third portion (<NUM>) provides both an axially directed seal (<NUM>) and a radially directed seal (<NUM>).