DESC:FIELD OF THE INVENTION:

The present invention generally relates to filters/pads in a carbon canister and more particularly, to a filter assembly having mesh filters for providing air ventilation for the carbon canister used in an evaporative emission control system.

BACKGROUND OF THE INVENTION:

A carbon canister is used to trap and adsorb fuel vapor emissions from the fuel tank of a vehicle. It is part of the evaporative emission control system used to reduce air pollution. In an internal combustion engine, fuel vapors are generated from the fuel tank due to temperature change and agitation. These vapors contain volatile organic compounds that contribute to air pollution and the formation of smog. The carbon canister is designed to adsorb these vapors and prevent them from escaping into the environment. The carbon canister installed vehicle reduces air pollution by preventing hydrocarbon vapors from escaping into the atmosphere. Further, the carbon canister improves fuel economy by preventing hydrocarbon vapors from being drawn into the engine. It also prevents the formation of smog.

The carbon canister is usually located in the engine compartment or near the fuel tank. The filters used in existing carbon canisters consist of various types of media that are specially designed for sufficient air ventilation to adsorb/desorb fuel vapors and volatile organic compounds. The most common types of filters used in the carbon canisters include activated carbon filters, desiccant filters, non-woven filters and reticulated foam.

Activated carbon is a highly porous material with a large surface area that effectively adsorb and desorb fuel vapors and volatile organic compounds. Activated carbon can be in the form of pellets, granules, or honeycomb, depending on the specific design of the canister.
Non-woven filters are made of synthetic fibers or other materials. Non-woven filters are designed to capture and retain particles, dust, and other contaminants that may be present in the fuel vapor stream and atmosphere. Non-woven filters are used as a pre-filter to protect the activated carbon. However, non-woven filters in the carbon canister get easily clogged by dirt and other contaminants. This reduces the airflow through the filter which impair the performance of the carbon canister. Further, non-woven filters are more susceptible to damage from moisture and chemicals. This shortens the lifespan of the filter and lead to premature failure of the carbon canister. Also, they are ineffective at trapping hydrocarbon vapors. This led to increased emissions of harmful pollutants into the atmosphere.

Accordingly, there exists a need to provide a filter assembly for a carbon canister that gives better protection against clogging, damage, and ineffectiveness, and overcomes the above-mentioned drawbacks in the prior art.

OBJECTS OF THE INVENTION:

The primary object of present invention is to provide a filter for a carbon canister that gives better protection against clogging, damage, and ineffectiveness.

Another object of the present invention is to provide a mesh filter for a carbon canister that effectively and easily fix in the canister case.

Still another object of the present invention is to provide efficient and proper ventilation during adsorption and desorption in the carbon canister without carbon leakage.

Further object of the present invention is to provide a mesh filter for the carbon canister that is reusable, reliable and durable.

SUMMARY OF THE INVENTION:
Accordingly, the present invention provides a filter assembly for a carbon canister. The filter assembly comprises a top filter and a bottom filter. The top filter is disposed above a liquid trap of the carbon canister and an atmospheric port. The bottom filter is positioned below a compression plate of the carbon canister. In accordance with the present invention, the top filter and the bottom filter include a mesh having a series of evenly spaced micro holes. Specifically, size of the micro holes of the mesh of the top filter and the bottom filter is 2 to 5 microns. The top filter and the bottom filter are made of plastic material selected from a high-density polyethylene (HDPE), polypropylene (PP), a polyamide 6 (PA6) material, and a polyamide 6-6 (PA66) material. The filter assembly of the present invention is capable of maintaining a long-term effectiveness and performance of the canister for sufficient air flow during adsorption and desorption. The filter assembly of the present invention is relatively inexpensive, easy to manufacture, durable, re-cyclable and resistant to clogging.

BRIEF DESCRIPTION OF THE DRAWINGS:

The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figures 1a and1b illustrate a perspective view of a filter assembly of a carbon canister, in accordance the present invention; and

Figure 2 illustrates a closer view of a mesh of the filter, in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION:

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with the prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a filter assembly for a carbon canister. The filter assembly includes plastic mesh filters having micro holes. The micro holes provide efficient ventilation during adsorption and desorption in the carbon canister without carbon leakage. Thus, the filter assembly holds the carbon particles in the case without leakage and provide sufficient air flow.

This present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in the table below:
Component Name Component Number Component Name Component Number
Carbon canister 100 Top filter 5
Casing 1 Bottom filter 6
Bottom cover 2 Spring 7
Compression plate/ Grid 3 Activated carbon 8
Liquid trap 4 Mesh/grid-like structure 10

Referring to figures 1a – 1b, a carbon canister (100) in accordance with the present invention is shown. The carbon canister (100) comprises a housing (1), a bottom cover (2), a compression plate/grid (3), a liquid trap (4), a spring (7), a filter assembly, and an activated carbon (8).

The bottom cover (2) is configured for sealing the complete housing (1) that houses the individual components of the carbon canister (100) in compact state. The spring (7) is configured for keeping the activated carbon (8) bed in compact state. In an embodiment, the spring (7) keeps the activated carbon bed in compact condition. The liquid trap (4) is configured to store the condensed fuel vapors in liquid form and to avoid spread of liquid fuel into the carbon. Further, the activated carbon (8) is configured to adsorb and desorb the fuel vapors containing as hydrocarbons.
As shown in figure 1a, the filter assembly includes a top filter (5) and a bottom filter (6). The top filter (5) is disposed above the liquid trap (4) and an atmospheric port. The bottom filter (6) is positioned below the compression plate (3). Thus, the top filter (5) and the bottom filter (6) are located at top and bottom of the housing (1) and are compatible with the overall design and structure of the carbon canister (100). The filters (5 and 6), typically installed at the inlet, outlet and atmospheric ports of the carbon canister (100), serve as a first line of defence against particulate matter entering the system.

As shown in figure 2, the top filter (5) and the bottom filter (6) include a mesh/grid-like structure (10). The mesh (10) includes a series of evenly spaced micro holes/ openings or pores throughout therein. The micro holes provide efficient ventilation during adsorption and desorption in the carbon canister (100) without carbon leakage. In a preferred embodiment, the size of the micro holes is 2 to 5 microns. However, it is understood here that the size and design of the mesh filter may vary depending on the specific requirements/ application of the carbon canister (100) and the desired level of filtration. In accordance with the present invention, factors such as the flow rate, desired filtration efficiency, and the characteristics of the fuel vapor stream are taken into account when determining the appropriate mesh size and design. The pore size of the mesh (10) is important as it determines the size of the particles that can pass through the filters (5 and 6). The filtering mesh with micro holes allow the passage of air or gas, provide efficient and proper ventilation during adsorption and desorption of the granules while blocking larger particles from entering the carbon canister (100).

In an embodiment, the top filter (5) and the bottom filter (6) are made of plastic material selected from a high-density polyethylene (HDPE), polypropylene (PP), a polyamide 6 (PA6) material, and a polyamide 6-6 (PA66) material. The plastic materials are selected for their durability, chemical resistance, and ability to withstand the harsh conditions within the carbon canister (100). In the context of the present invention, the micro holes are made on the plastic materials by using any one of a laser, drilling, molding or any new technology. Thus, the filtering mesh is woven to create a specific pore/ micro hole size that allows air to pass through it without leaking carbon particles.

In accordance with the present invention, the filters (5 and 6) are configured to prevent larger particles, such as dust, dirt, or debris, from entering the carbon canister (100). The filters (5 and 6) act as a mechanical barrier, capturing these particles and preventing them from reaching and clogging the more delicate activated carbon or other filtering media. Further, the filters (5 and 6) block the dirt and ensure the air that enters the canister is clean and free of contaminants. The filters (5 and 6) can be used in conjunction with other types of filters such as activated carbon filters as per the intended use in exemplary embodiment of the present invention. These filters work together to provide a multi-stage filtration process, with the filtering mesh acting as a preliminary barrier to protect the subsequent filtration media from larger particles.

ADVANTAGES OF THE INVENTION:

1. The filter assembly gives better protection against clogging, damage, and ineffectiveness in the carbon canisters (100) by preventing larger particles from entering and potentially clogging the more sensitive filtering media.
2. The filter assembly is capable of maintaining a long-term effectiveness and performance of the carbon canister (100) for sufficient air flow during adsorption and desorption.
3. The filter assembly is relatively inexpensive and easy to manufacture.
4. The filter assembly is durable, re-cyclable and resistant to clogging.
5. The filter assembly can be used with a variety of pore sizes.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the scope of the invention. ,CLAIMS:We Claim:

1. A filter assembly for a carbon canister (100), the filter assembly comprising:
a top filter (5) disposed above a liquid trap (4) of the carbon canister (100) and an atmospheric port; and
a bottom filter (6) positioned below a compression plate (3) of the carbon canister (100),
characterized in that, the top filter (5) and the bottom filter (6) include a mesh (10) having a series of evenly spaced micro holes.

2. The filter assembly as claimed in claim 1, wherein size of the micro holes of the mesh (10) of the top filter (5) and the bottom filter (6) is 2 to 5 microns.

3. The filter assembly as claimed in claim 1, wherein the top filter (5) and the bottom filter (6) are made of plastic material selected from a high-density polyethylene (HDPE), polypropylene (PP), a polyamide 6 (PA6) material, and a polyamide 6-6 (PA66) material.