FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003 As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
Axial flow filter arrangement for air filtration
APPLICANT
Filtrum Fibretechnologies Pvt. Ltd, Gat No.- 87/1 & 87/2, Village - Nandur, Tal - Daund, Dist - Pune, Pin -412202. Maharashtra.
INVENTOR
Payyappilly Antony Thomas, Gat No.- 87/1 & 87/2, Village - Nandur, Tal - Daund, Dist -Pune, Pin -412202. Maharashtra.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention.

BACKGROUND
FIELD OF THE INVENTION
The present invention relates generally to an air intake system of an internal combustion engine. More particularly, the present invention relates to an air filter for the internal combustion engine.
DESCRIPTION OF THE RELATED ART
An internal combustion engine requires air to generate power. The air to be introduced into the engine must be clean to ensure its safe operation. Hence, an air filter is commonly used to remove contaminants from the air. The air filter includes a filter media that traps the contaminants from the air when the air flows through the filter media. The filter media performs the function of a strainer to remove the contaminants from the air.
Traditionally, air filters incorporate a pleated filter element for the filtration of air. However, the pleated filter element has an inadequate surface area compared to an axial flow filter, specifically a spiral filter element. The surface area of the pleated filter element can be increased by placing more pleats closer to each other. However, this results in increased flow restriction. The spiral filter element has come into use due to its large surface area for filtration. The spiral filter element (or cartridge) has a perforated supporting core contained within a casing. The spiral filter element is usually assembled by winding multiple layers of filter media around the supporting core. Typically, the air enters from a top end of the casing and then flows radially through the multiple layers of filter media that may be separated by spacers. The multiple layers of filter media trap the contaminants as the air passes through the spiral filter element. Filtered air is drawn off from a bottom end of the spiral filter element. The advantage conferred by the use of such filter element is higher separation efficiency per unit of filter media employed than that of other filter elements.
A consequence of such type of filtration is the eventual clogging of filter media by the captured contaminants when air enters from a top end of the spiral filter element. This leads to a low

delivery volume of the air to an engine conduit. Usually, casings of filters are designed so as to facilitate periodic cleaning and disposal of the collected contaminants. A consequence of this method of cleaning is that it requires the engine to be shut off and a filter element to be disassembled.
A problem typical of the spiral filter element is that due to its design, the collected contaminants progressively accumulate in the filter media when air enters the spiral filter element from its top end. The filter media cannot be effectively cleaned by conventional means without damaging structure of the filter media. A solution to this problem is to have an inlet for the ingress of air at a bottom end of a filter assembly. This ensures that the separated dust gets dislodged from the filter media due to the force of gravity. The dislodged contaminants are expelled through an evacuation port. This requires a special construction of an inlet at the bottom end of the filter assembly to deliver air at a base of the spiral filter element. This is a disadvantageous design since it requires additional space to accommodate the inlet at the bottom end of the filter assembly in order to deliver air towards the base of the spiral filter element. This increases the complexity and the amount of space occupied by the filter assembly. Due to the high level of modularity in engine hood designs, the space allocated for an air filter assembly is limited by vehicle's geometry and engine's compartment size. Hence, this solution is not optimal in the practical deployment of the filter assembly.
In light of the foregoing, there exists a need for a spiral filter arrangement that prevents the progressive clogging of the spiral filter element. Moreover, there exists a need for the spiral filter arrangement that prevents the need for cleaning of the spiral filter element at regular intervals, thereby reducing complexity of structure of filter assembly and optimizing the space occupied by the filter assembly.
OBJECTS OF THE INVENTION
An object of the present invention is to provide an effective, cost efficient solution to eliminate the clogging of filter media during the operation of an axial flow filter.
Another object of the present invention is to provide an axial flow filter arrangement that eliminates the clogging of filter media and ensures space optimization in an engine compartment.

SUMMARY OF THE INVENTION
The invention discloses a fluid filter arrangement for filtering fluid. The fluid filter arrangement comprises: a bottom enclosure, a top enclosure, an axial flow filter, and a deflecting surface. The top enclosure has an inlet for receiving fluid into the fluid filter arrangement and is mounted on the bottom enclosure. The axial flow filter has a top end and a bottom end. The axial flow filter is mounted within the bottom enclosure. The deflecting surface is mounted on the top end of the axial flow filter. The deflecting surface has a conduit, which is a protruded portion of the deflecting surface, that extends outwardly from the top enclosure. A space that formed between the top enclosure and the deflecting surface defines a fluid passage for the fluid that enters from the inlet. The fluid enters the axial flow filter by means of the fluid passage through the bottom end of the axial flow filter and exits from the top end of the axial flow filter. Filtered fluid is vented out from the fluid filter arrangement through the conduit. Therefore, the fluid filter arrangement prevents clogging of the axial flow filter.
This design of the fluid filter arrangement ensures optimal delivery pressure as required by an engine. In order to take advantage of the dislodgement of dust from filter separation channels by gravity, this design manages to reduce the number of components and complexity required to supply the air to the bottom end of the axial flow filter. More, the fluid filter arrangement optimizes the spatial requirements of the axial flow filter.
BRIEF DESCRIPTION OF DRAWINGS
The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. Embodiments of the present invention will herein after be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:
Fig. 1A is a top isometric view of an air filter arrangement, in accordance with an embodiment of the present invention;
Fig. 1B is a front view of the air filter arrangement, in accordance with an embodiment of the present invention;

Fig. 1C is a side view of the air filter arrangement, in accordance with an embodiment of the present invention;
Fig. 1D is a front sectional view of the air filter arrangement, in accordance with an embodiment of the present invention; and
Fig. 1E is a side sectional view of the air filter arrangement, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
As used in the specification and claims, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "an article" may include a plurality of articles unless the context clearly dictates otherwise.
Those with ordinary skill in the art will appreciate that the elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated, relative to other elements, in order to improve the understanding of the present invention.
There may be additional components described in the foregoing application that are not depicted on one of the described drawings. In the event such a component is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification.
Before describing the present invention in detail, it should be observed that the present invention constitutes a spiral filter arrangement for an air filtration assembly. Accordingly, the components have been represented, showing only specific details that are pertinent for an understanding of the present invention so as not to obscure the disclosure with details that will be readily apparent to those with ordinary skill in the art having the benefit of the description herein.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
An air filter arrangement 100 of an air intake system (not shown) is shown in FIGS.1A-1E. The air filter arrangement 100 is in fluid communication with an internal combustion engine (hereinafter, referred to as an engine) to deliver a constant supply of filtered air to the engine. The air filter arrangement 100 includes a top enclosure 102 and a bottom enclosure 104 as illustrated in FIGS. 1A-1C. The top enclosure 102 is mounted on the bottom enclosure 104. The top enclosure 102 as seen in FIGS. 1A-1C is a hollow cap having a top end and a bottom end. The top enclosure 102 has an inlet 106 at the top end of the hollow cap. The inlet 106 receives atmospheric air from the air intake system.
The bottom enclosure 104 as illustrated in FIGS. 1A-1C is a hollow drum having a top end and a bottom end. In an embodiment, the bottom end of the hollow cap of the top enclosure 102 and the top end of the hollow drum of the bottom enclosure 104 are attached together by a locking clasp assembly. A press fit between the top enclosure 102 and the bottom enclosure 104 ensures sealing of the air filter arrangement 100. Any arrangement that allows the mounting of the top enclosure 102 on the bottom enclosure 104 is within scope of the invention. Moreover, a sealing element 108 may be disposed between the top enclosure 102 and the bottom enclosure 104 to achieve desirable sealing for the air filter arrangement 100.
The air filter arrangement 100 includes an evacuation port 110 positioned at the bottom end of the hollow drum of the bottom enclosure 104. A bottom surface of the hollow drum of the bottom enclosure 104 is tapered towards the evacuation port 110. This allows the contaminants to accumulate at center of the bottom surface which is further discharged out of the air filter arrangement 100 through the evacuation port 110. In a preferred embodiment, the evacuation port 110 may be located at the centre of the bottom surface of the bottom disclosure 104 as seen in FIG.1A to FIG. IB. In another embodiment, the evacuation port 110 may be located

eccentrically from the center on the bottom surface of the bottom enclosure 104. In an embodiment, the evacuation port 110 may have an automatically operated valve equipped with sensors to detect amount of dust collected. Upon collecting a pre-defined level of dust, the valve automatically opens to discharge the collected dust. In another embodiment, the evacuation port 110 may have a valve or a cap that would be manually operated by user in order to discharge the collected dust.
The air filter arrangement 100 further includes an axial flow filter 112. The axial flow filter 112 may be a spiral filter element, a honeycomb filter element, or the like. For better understanding of the invention, the axial flow filter 112 is the spiral filter element. The axial flow filter (hereinafter, referred to as 'spiral filter element 112 for easy understanding of the invention) as illustrated in FIGS.1D-1E has a filter media 114 composed of a plurality of overlapping filter media layers wound in a spiral or helical fashion about a perforated supporting core 116. The plurality of overlapping filter media layers may be separated from each other by the means of spacers to define separation channels. The spacers ensure structural rigidity of the filter media 114 while maintaining a uniform gap between the separation channels. The spiral filter element 112 has a top end 118a and a bottom end 118b as illustrated in FIGS.1D-1E. Further, the spiral filter element 112 has a lateral surface formed by the filter media 114. The lateral surface of the filter media 114 prevents the atmospheric air to flow through the filter media 114. The perforated supporting core 116 as depicted in FIGS. 1D-1E may be a cylindrical tube or a hollow rectangular plate that is sealed at one end. The perforated supporting core 116 has a plurality of perforations along its length. The atmospheric air flows in a radial direction (both inwards and outwards) through the separation channels and enters the perforated supporting core 116 through the plurality of perforations. The contaminants are preferentially decelerated and trapped within the separation channels, leading to dust collection.
The spiral filter element 112 is secured within the bottom enclosure 104 by way of a mounting arrangement 120. In an embodiment, the mounting arrangement 120 is a L-shaped sectional flange that securely mounts the spiral filter element 112 in the bottom enclosure 104. One end of the mounting arrangement 120 is secured to the top end of the bottom enclosure 104 and another end of the mounting arrangement 120 is secured to the spiral filter element 112. In an embodiment, the mounting arrangement 120 having a through hole is contiguous around the spiral filter element 112 to ensure the secure mounting of the spiral filter element 112 in the

bottom enclosure 104. This ensures minimal movement or distortion of the spiral filter element 112 during filtering operation. In another embodiment, two or more flanges are spaced at regular intervals to ensure the secure mounting of the spiral filter element 112 in the bottom enclosure 104. The mounting arrangement 120 may be made of a polymeric material. In another embodiment, the mounting arrangement 120 may be made of materials such as stainless steel, aluminum, and plastic.
The air filter arrangement 100 further includes a deflecting surface 122. The deflecting surface 122 may be a dome shaped profile, a conical profile, a cuboidal profile, or any other curved profile. In a preferred embodiment, the deflecting surface 122 is the dome shaped profile. The deflecting surface 122 (hereinafter, referred to as a "dome 122") is mounted on the top end 118a of the spiral filter element 112 as illustrated in FIG.1D and FIG. 1E. The dome 122 has a conduit 124 that is a protruded portion of the dome 122 and extends outwardly from the hollow cap of the top enclosure 102. The conduit 124 forms an outlet for the air filter arrangement 100 to allow filter air out of the air filter arrangement 100. In an embodiment, the dome 122 is housed in the top enclosure 102. The connection between the dome 122 and the spiral filter element 112 is sealed by a sealing arrangement 126 as illustrated in FIGS. ID-IE. The sealing arrangement 126 is disposed between the top end 118a of the axial flow filter 112 and a bottom end of the dome 122 to prevent passage of the fluid from the inlet 106 into the conduit 124. The sealing arrangement 126 prevents the entry of unfiltered air into the dome 122. The dome 122 may be made of materials such as polymers, plastic, and aluminum. The profiles of the top enclosure 102 and dome 122 lead to formation of a space 128 that defines a fluid passage between an inner surface of the hollow cap of the top enclosure 102 and an outer surface of the dome 122. The fluid passage extends continuously from the inlet 106 of the top enclosure 102 to the bottom surface of the top enclosure 102. The arrangement of the dome 122 and the spiral filter element 112 is such that air can enter the spiral filter element 112 from the bottom end 118b of the spiral filter element 112. Moreover, filtered air that exists from the top end 118a of the spiral filter element 112 is received by the dome 122 and is finally vented out to the engine through the conduit 124.
Air enters the top enclosure 102 of the air filter arrangement 100 by means of the inlet 106 and is directed into the bottom enclosure 104 by means of the fluid passage. The air laden with contaminants and dust enters into the spiral filter element 112 via the bottom end' 118b of the spiral filter element 112. The air interacts with the plurality of filter media layers of the spiral

filter element 112, wherein the dust and contaminants are trapped within the layers of filter media thus filtering the air. The filtered air exits the spiral filter element 112 from the top end 118a and is collected in the dome 122. The sealing arrangement 126 ensures that filtered air does not mix with the air entering via the inlet 106 of the top enclosure 102. This collected filtered air then travels out of the air filter arrangement 100 towards the engine by means of the conduit 124 of the dome 122. The suction pressure generated by the operation of the engine provides the driving force for the air to flow through the filter media 114 from the bottom end 118b to the top end 118a of the spiral filter element 112.
In an embodiment, the top and bottom enclosures 102 and 104, and the dome 122 may be made of a polymeric material. In another embodiment, the top and bottom enclosures 102 and 104, and the dome 122 may be made of materials such as stainless steel, aluminum, or plastic. In yet another embodiment, the air filter arrangement 100 has a housing, which is a unitary structure, having an inlet. The housing is a unitary structure formed by adjoining the top enclosure 102 and the bottom enclosure 104. Specifically, the housing of the air filter arrangement 100 is not divided into two enclosures but is the unitary structure.
Due to the mounting of the spiral filter element 112 as depicted in FIG. 1D and FIG. 1E, the dust and contaminants trapped within the filter media layers of the spiral filter element 112 as a result of the filtration process are easily dislodged due to the force of gravity, thereby ensuring minimal dust compaction in the spiral filter element 112. The dislodged dust is collected onto the bottom surface of the bottom enclosure 104 and migrates towards the evacuation port 110 due to the tapered design of the bottom surface of the bottom enclosure 104.
This design prevents clogging of the spiral filter element 112, thus ensuring optimal delivery pressure as required by the engine. In order to take advantage of the dislodgement of dust from filter separation channels by gravity, this design manages to reduce the number of components and complexity required to supply the air to bottom of the air filter arrangement 100. This optimizes the spatial requirements of the air filter arrangement 100 in the air intake system. Moreover, this design ensures that the air filter arrangement 100 can be retro-fitted to existing engine hood designs. An additional advantage conferred by the design of the top enclosure and bottom enclosure 102 and 104 is that, in case the spiral filter element 112 is damaged or clogged, it can be replaced very easily.

The present invention has been described herein with reference to a particular embodiment for a particular application. Although selected embodiments have been illustrated and described in detail, it may be understood that various substitutions and alterations are possible. Those having ordinary skill in the art and access to the present teachings may recognize additional various substitutions and alterations are also possible without departing from the spirit and scope of the present invention.

We claim:
1. A fluid filter arrangement for filtering fluid, the fluid filter arrangement comprising:
a bottom enclosure;
a top enclosure having an inlet for receiving fluid into the fluid filter arrangement, wherein the top enclosure is mounted on the bottom enclosure;
an axial flow filter, having a top end and a bottom end, mounted within the bottom enclosure; and
a deflecting surface, having a conduit, mounted on the top end of the axial flow filter, wherein the conduit is a protruded portion of the deflecting surface and extends outwardly from the top enclosure, wherein a space between the top enclosure and the deflecting surface defines a fluid passage for the fluid that enters from the inlet, wherein the fluid enters the axial flow filter by means of the fluid passage through the bottom end of the axial flow filter and exits from the top end of the axial flow filter, and wherein filtered fluid exits from the fluid filter arrangement through the conduit.
2. The fluid filter arrangement of claim 1 further comprising an evacuation port that is mounted to the bottom enclosure to discharge separated particles.
3. The fluid filter arrangement of claim 1, wherein the deflecting surface is a dome shaped profile.
4. The fluid filter arrangement of claim 1 further comprising a mounting arrangement to securely mount the axial flow filter within the bottom enclosure.
5. The fluid filter arrangement of claim 1 further comprising a sealing arrangement disposed between the top end of the axial flow filter and a bottom end of the deflecting surface to prevent passage of the fluid from the inlet into the conduit.
6. A fluid filter arrangement for filtering fluid, the fluid filter arrangement comprising:
a housing having an inlet for receiving fluid into the fluid filter arrangement;
an axial flow filter, having a top end and a bottom end, mounted within the housing; and
a deflecting surface, having a conduit, mounted on the top end of the axial flow filter, wherein the conduit is a protruded portion of the deflecting surface and extends outwardly from the housing, wherein a space between the deflecting surface and an inner surface of the housing defines a fluid passage for the fluid that enters from the

inlet, wherein the fluid enters the axial flow filter by means of the fluid passage through the bottom end of the axial flow filter and exits from the top end of the axial flow filter, and wherein filtered fluid exits from the fluid filter arrangement through the conduit.
7. The fluid filter arrangement of claim 6, wherein the deflecting surface is a dome shaped profile.
8. The fluid filter arrangement of claim 6 further comprising a sealing arrangement disposed between the top end of the axial flow filter and a bottom end of the deflecting surface to prevent passage of the fluid from the inlet into the conduit.