Gas separation – Residue access – handling or removing means
Reexamination Certificate
2001-10-09
2002-07-02
Bushey, C. Scott (Department: 1724)
Gas separation
Residue access, handling or removing means
C055S432000, C055S476000, C055S498000, C055S502000
Reexamination Certificate
active
06413289
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to reverse flow air cleaner arrangements. That is, the invention concerns air cleaner arrangements wherein filtering flow is in a direction with the “clean” side of the air filter being around an exterior thereof, and the “dirty” side of the air filter being along an interior thereof. The invention particularly concerns such air cleaner arrangements having drainage systems for water accumulating in an interior of associated air filter elements. The invention also concerns provision of preferred components, such as air filter elements, for use with such arrangements; and, to methods involving the use of such arrangements.
BACKGROUND OF THE INVENTION
In general, air cleaner arrangements include a housing and an air filter element. The housing is configured such that air is directed through the air filter element, for filtering. Various geometric configurations of the air cleaner housing, the air filter element, and related seal arrangements are used to effect this.
Many air cleaner arrangements include generally cylindrical air filter elements. Such elements typically include filter media arranged in a cylindrical pattern, with end caps. Seal arrangements are used either on or in conjunction with the end caps, to provide appropriate sealing with the housing or other portions of the air cleaner, and to control the direction of air flow.
Reverse air flow air cleaner arrangements are generally those in which air is directed to an interior of the air filter element before it is filtered, and the air is filtered as it passes through the air filter element from the interior to the exterior. If the air filter element is cylindrical, this means that the unfiltered air is directed into the interior of the cylinder, and then through the filter media, to an exterior, during filtering. Material entrained in the air directed into the air filter, then, is left along an interior of the cylindrical filter media.
Consider, for example, a reverse flow air cleaner arrangement, having a cylindrical air filter element, utilized on an over the highway truck. Air directed into the interior of the cylindrical element may include dust, leaves, large particulates, and even moisture entrained wherein. This material will tend to build up in the interior of the air filter element, in time. If the water depth inside the air filter becomes significant, the water, alone or with fine particulates or salt in suspension, can permeate the filter media. This has the potential to damage engine components. It would be preferred that arrangements be provided to drain the water from the interior of the filter element.
In those arrangements wherein the filter element is operationally oriented such that the longitudinal axis of the cylindrical air filter is substantially vertical, drainage arrangements involving drainage apertures in one of the end caps have been used. In general, these have involved offset (from a central location) apertures in one end cap, and unless the air filter element is oriented nearly perfectly vertically, drainage is inefficient. Also, in such arrangements debris can sometimes collect along interior surfaces of the housing when the arrangement is opened and the element is removed; and, unless the housing is thoroughly cleaned before the element is reinserted into the housing, the debris can interfere with attainment of a good seal at critical locations.
Summary of the Disclosure of U.S. Ser. No. 08/742,244
According to the disclosure of U.S. Ser. No. 08/742,244, an air filter arrangement is provided. The air filter arrangement includes a housing and an air filter element having first and second opposite end caps, filter media and an open filter interior. The first end cap has an air inlet opening therein, for air to be passed into the arrangement to be filtered. The second end cap has a central drainage aperture and an interior surface constructed and arranged to funnel moisture that collects on the second end cap interior surface to the central drainage aperture, and outwardly from the filter element. The central drainage aperture is preferably positioned at a center of the second end cap, with a longitudinal axis of the air filter element passing therethrough. The air filter arrangement also includes an air flow direction arrangement constructed and arranged to direct air flow into the housing, into the open filter interior, through the filter media for filtering and then outwardly from the housing, as filtered air. The air flow direction arrangement generally comprises various features of the housing, seals and filter element.
Preferably, the interior surface of the second end cap is circular. In certain embodiments it includes a plurality of radially directed troughs which terminate in the central drainage aperture. The troughs can be used to help funnel and direct moisture collected on an interior surface of the air filter element in use (i.e., “when operationally” or “operatively” assembled).
In certain preferred arrangements, according to the U.S. Ser. No. 08/742,244 disclosure, the second end cap includes an outer annular compressible portion and the housing includes an annular sealing surface against which the second end cap outer annular compressible portion is sealed, when the air filter arrangement is operatively assembled for use. Such a seal is referred to herein as a peripheral or annular radial seal, around the second end cap. That is, in this context the term “annular” refers to a sealing portion around the outside of the end cap, which seals under radial compression.
In a preferred embodiment, according to the U.S. Ser. No. 08/742,244 disclosure, the housing includes a base having a central, preferably recessed, pan and a sealing bead circumferentially positioned around the central recessed pan. A drainage aperture is provided in the central pan, so that water collected in the pan can be removed from the housing. With such an arrangement, preferably the second end cap is constructed and arranged to form a secondary seal with the sealing bead in the base, when the air filter element is operatively positioned within the housing. Preferably the manner of engagement with the seal bead is by provision of a mating “trough” in the second end cap outer surface.
According to the U.S. Ser. No. 08/742,244 disclosure, preferably the second end cap outer surface has an outer edge or lip; and, the second end cap outer surface is recessed (or depressed) in extension between the outer edge and the trough which engages the sealing bead and the base. In this manner, a preferred gap or space is provided between the filter element second end cap, and the housing base, in the region between the sealing bead of the base and an outer peripheral area of the base. A space in this location accommodates debris that may collect in the housing, without interference with the seal between the second end cap and the housing. This is facilitated by those arrangements involving provision of the seal along an annular portion of the end cap, as a radial seal, rather than as an end or axial seal.
According to the U.S. Ser. No. 08/742,244 disclosure, preferably the second end cap outer surface is configured to provide a funnel surface having a declination angle of at least about 1°, and preferably 1° to 3°, in the region of extension between the outer edge of the second end cap and the portion of the end cap which engages the seal bead in the base.
In preferred arrangements, according to the U.S. Ser. No. 08/742,244 disclosure, an evacuation valve is mounted in the drainage aperture of the recessed pan in the base. This provides for a preferred, controlled, drainage of moisture from the system.
In preferred embodiments, according to the U.S. Ser. No. 08/742,244 disclosure, a soft polymeric material is utilized for the first and second end caps. Preferably each of the polymeric end caps comprise polyurethane. For the end caps, a polyurethane foam material having an “as molded” density of about 14-22 lbs per ft
3
will be preferred (most preferably about 18.4). I
Bartels Dolan
Crenshaw Bruce
Engel Donald Francis
Hacker John
Harold Don
Bushey C. Scott
Donaldson & Company, Inc.
Harold Shirley A.
Merchant & Gould P.C.
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