Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. TITLE OF THE INVENTION
SELF-CLEANING AIR FILTER ASSEMBLY WITH CONTINUOUS OPERATION CAPABILITY
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
FLEETGUARD FILTERS PRIVATE LIMITED AN INDIAN COMPANY 136, PARK MARINA ROAD, BANER, PUNE, MAHARASHTRA, INDIA, PIN CODE - 411045
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE INVENTION
[001] The present invention relates to the field of air filtration. More particularly, the present invention relates to self-cleaning air filter assemblies for use in various applications, including but not limited to vehicles, industrial equipment, and heating ventilation and air conditioning (HVAC) systems, where efficient and continuous air filtration is required for optimal performance and longevity.
DEFINITION
[002] The terms “air,” “gas,” and “fluid” are used interchangeably to mean any fluid at normal, elevated, or compressed pressures. The invention, while described with reference to air or gas, applies to any fluid, such as air, nitrogen, or other gases.
[003] “Filter restriction” is the resistance to airflow caused by the filter media, accumulated contaminants, or structural obstructions, leading to reduced engine performance, efficiency, and increased fuel consumption.
[004] “Cleaning efficiency” refers to the effective removal of dust and debris, reducing filter restriction and maintaining optimal airflow, longevity, and performance.
[005] The terms “filter,” “filter element,” and “filter media” are used interchangeably to denote components that filter air, fluid, or gas, potentially supported by elements like end plates and center tubes, the configurations being well known in the art.
BACKGROUND OF THE INVENTION
[006] Air filtration assemblies play a major role in various industries, particularly in automotive and heavy equipment sectors, where clean air is required for optimal engine/equipment performance and longevity. Conventional air filters, while effective initially, suffer from a significant drawback: they accumulate dust, debris, and other particulates over time, leading to increased airflow restriction and reduced filtration efficiency.
[007] As the filters become clogged, frequent replacements of the filters is necessitated, resulting in higher maintenance costs, increased vehicle downtime, and potential damage to engines if not addressed promptly. The issue is particularly pronounced in environments with high dust concentrations, such as construction sites, mines, and agricultural areas.
[008] To address the aforementioned challenges, self-cleaning air filter assemblies have been developed. The self-cleaning air filter assemblies typically employ various mechanisms to dislodge accumulated particles from the filter media, extending the filter's operational life and maintaining consistent performance. Some common self-cleaning techniques include reverse air flow, mechanical shaking, and compressed air pulses.
[009] In reverse air flow technique, the direction of airflow is periodically reversed through the filter, attempting to blow off collected particles. However, the reverse air flow technique often fails to remove deeply embedded contaminants and may be less effective for fine particles that adhere strongly to the filter media.
[0010] Mechanical shaking or vibration technique physically agitate the filter element to dislodge debris. While effective for larger particles, the mechanical or vibration technique may struggle with fine dust removal and may potentially cause premature wear of the filter element and supporting structures due to repeated mechanical stress.
[0011] Compressed air pulse technique typically direct short bursts of high-pressure air from the clean side to the dirty side of the filter. The compressed air pulse or short bust technique may be effective, but often faces challenges in achieving uniform cleaning across the entire filter surface, leaving some areas still clogged. Additionally, the high-pressure pulses may potentially damage the filter media over time, reducing its overall lifespan.
[0012] Moreover, many conventional self-cleaning air filter assemblies require the main filtration process to be interrupted during the cleaning cycle. Such interruption may be problematic in applications that demand continuous air supply, such as in vehicle engines operating in dusty environments or certain industrial processes where downtime is costly.
[0013] Despite numerous advancements, the conventional self-cleaning air filter assemblies still face significant limitations in cleaning efficiency, filter longevity, post-cleaning restriction, and operational continuity. Therefore, there is a need for a self-cleaning air filter assembly that is capable of operating continuously, allowing efficient cleaning cycles without interrupting the primary filtration process or engine operation. Further, there is a need for a self-cleaning air filter assembly that ensures thorough and uniform cleaning, effectively remove both large debris and fine particulates while preserving the filter media's integrity, thereby minimizing post-cleaning restriction, downtime and maximizing operational efficiency.
OBJECTS OF THE INVENTION
[0014] Some of the objects of the presently disclosed invention, of which at the minimum one object is fulfilled by at least one embodiment disclosed herein, are as follows.
[0015] An object of the present invention is to provide an alternative, which overcomes at least one drawback encountered in the existing prior art.
[0016] Another object of the present invention is to provide a self-cleaning air filter assembly that achieves high cleaning efficiency, and low restriction value without compromising the integrity or lifespan of the filter media.
[0017] Still another object of the present invention is to provide a self-cleaning air filter assembly that ensures uniform cleaning across the entire filter surface, effectively removing both large debris and fine particles adhering to the filter media.
[0018] Yet another object of the present invention is to provide a self-cleaning air filter assembly that is capable of operating continuously, allowing cleaning cycles without interrupting the main filtration process, even when the engine is running.
[0019] A further object of the present invention is to provide a robust and durable self-cleaning air filter assembly that minimizes the need for frequent replacements, thereby reducing maintenance costs and vehicle downtime.
[0020] Still another object of the present invention is to provide a self-cleaning air filter assembly that optimizes the distribution and impact of cleaning air pulses, enhancing the overall cleaning effectiveness of the assembly.
[0021] An additional object of the present invention is to provide a self-cleaning air filter assembly that is capable of functioning efficiently in high-dust environments, maintaining optimal engine performance and protection under challenging operating conditions.
[0022] Other objects and benefits of the present invention will be more apparent from the following description, which is not intended to bind the scope of the present invention.

SUMMARY OF THE INVENTION
[0023] The present invention relates to self-cleaning air filter assemblies, which provide efficient and continuous air filtration for optimal performance and longevity of equipment.
[0024] The self-cleaning air filter assembly of the present invention comprises a substantially cylindrical housing with first and second ends, which are closed by a first cover plate and a second cover plate, respectively. The self-cleaning air filter assembly further includes a cylindrical, annular pleated filter element positioned concentrically within the housing. The filter element features an annular pleated filter media wall, a first end plate with a central aperture, and a closed second end plate. An annular gap is maintained between the filter element's outer surface and the housing's inner surface, forming the dirty side of the assembly. The filter element encloses an interior space, creating the clean side of the assembly. An air inlet port configured on the housing directs incoming air into the annular gap for cleaning. A dust outlet port expels separated dust. A clean air outlet port is configured on the first cover plate of the housing. The air outlet port is in fluid communication with the interior space and registers with the central aperture of the first end plate, permitting filtered air to exit the assembly. A tube, placed along the longitudinal axis of the filter element within the interior space, has a plurality of holes configured thereon. Multiple nozzles, one each are coupled to a hole in the tube, are designed with a hollow body terminating in a chamfered second free end with a chamfer angle (φ) ranging from 15° to 70°. The tube is connected to a source of pressurized gas or pressurized air, which is pumped through the tube and nozzles to clean the filter element.
[0025] In accordance with one embodiment of the present invention, the length-to-diameter ratio of each nozzle is specified to be in the range of 2:1 to 5:1, and the tube's length-to-diameter ratio is defined within the range of 8:1 to 16:1.
[0026] In accordance with one embodiment of the present invention, each nozzle's chamfered shape is characterized by a chamfer length-to-nozzle length ratio ranging from 1:5 to 1:10, the distance between each nozzle and the inner periphery of the annular pleated filter media wall is set to be in the range of 15% to 50% of the diameter of interior space, the number of nozzles is chosen such that the angle (ϑ) between adjacent nozzles, as measured from the center of the tube, falls within the range of 22.5 to 90 degrees, and the spacing between adjacent nozzles along the length of the tube is designated to be in the range of 15% and 25% of the tube's length.
[0027] In accordance with one embodiment of the present invention, the tube is secured within the interior space using fixtures or butterfly bolts, the source of pressurized gas is configured to supply gas at a pressure ranging from 4 bar to 6 bar, and each nozzle may have a cross-sectional shape selected from the group consisting of circular and rectangular forms.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[0028] The present invention is now described with reference to the accompanying drawing, in which like reference numerals indicate identical or functionally similar elements throughout the several views.
[0029] FIG. 1 illustrates a schematic cross-sectional view of a self-cleaning air filter assembly in accordance with the embodiments of the present invention.
[0030] FIG. 2 illustrates a schematic cross-sectional view of a tube with nozzles in accordance with the embodiments of the present invention.
[0031] FIG. 3 illustrates a schematic cross-sectional view of a nozzle in accordance with the embodiments of the present invention.
LIST OF NUMERALS
[0032] To facilitate a clear understanding of the invention, reference is made to the accompanying drawing where components are identified by specific reference numerals. The following list provides the reference numerals alongside their corresponding components:
1 - Self-cleaning air filter assembly
10 - Cylindrical housing
11 - First end of housing
12 - Second end of housing
13 - Cylindrical wall
14 - First cover plate
15 - Opening in first cover plate
16 - Second cover plate
20 - Cylindrical, annular pleated filter element
21 - Annular pleated filter media wall
22 - First end plate
23 - Central aperture in first end plate
24 - Closed second end plate
25 - Clean air outlet port
30 - Annular gap
40 - Interior space
50 - Air inlet port
60 - Dust outlet port
70 - Tube
80 - Nozzles
81 - First end of nozzle
82 - Second free end of nozzle
83 - Body
84 - Chamfer
100 - Fixtures or butterfly bolts

DETAILED DESCRIPTION
[0033] The present invention pertains to the domain of air filtration. More specifically, the present invention relates to self-cleaning air filter assemblies applicable in a multitude of contexts, encompassing, vehicular systems, industrial machinery, and heating, ventilation, and air conditioning (HVAC) systems, wherein efficacious and unremitting air filtration is imperative for the optimal functionality and durability of the apparatuses.
[0034] In this context, within the ensuing description and appended claims, adherence to specialized lexicon and technical terminology is mandated, with interpretations thereof aligning with their conventional meanings ascribed within the pertinent field, unless explicitly redefined within the context.
[0035] Throughout the exposition and associated claims, the use of singular forms such as "a," "an," and "the" is intended to encompass plural references, thereby embracing diverse instances unless the context unequivocally necessitates a singular interpretation. Similarly, the inclusion of terms like "one," "a," "an," or "the" is deemed inclusive of both singular and plural manifestations, unless the context decidedly dictates otherwise.
[0036] Sequential designations, denoted by terms such as "first," "second," "third," and the like, serve exclusively to differentiate between various elements or components and do not imply any inherent sequence or hierarchical structure, unless explicitly stipulated or inferred from the context.
[0037] The term "may" conveys a sense of possibility or alternative rather than obligation, unless expressly mandated by the contextual milieu.
[0038] References to specific materials, compositions, or substances inherently encompass their functional equivalents unless explicitly specified otherwise by the context.
[0039] Expressions delineating spatial orientation such as "upper," "lower," "top," "bottom," "front," "rear," "side," and the like, serve solely to describe the relative positioning or orientation of elements or components within the disclosed embodiments and should not be construed as confining the invention to any particular spatial configuration unless explicitly declared or inferred from the context.
[0040] Terms such as "coupled," "connected," and "attached," including their variations, are utilized interchangeably and do not impose limitations on the nature of connection or attachment, unless explicitly necessitated by the context.
[0041] Numeric values specified within this discourse are inherently inclusive of a range extending approximately 10% below and above the stated value, unless an alternate range is expressly delineated.
[0042] Phrases such as "in one embodiment" are not indicative of identical embodiments but rather denote distinct instances that may represent different facets or aspects of the invention.
[0043] The terms "optional" or "optionally" signify that subsequent elements, steps, or features may or may not be encompassed within the scope of the invention, contingent upon specific embodiments or implementations.
[0044] When qualifiers like "substantially" or "essentially" are employed to characterize a characteristic or property, they encompass variations recognized by one skilled in the relevant field as not significantly altering the intended outcome or performance of the described embodiment.
[0045] The term "comprising," utilized herein, signifies inclusivity and openness, allowing the incorporation of additional elements, features, components, process steps, sub-steps, and/or aspects as deemed suitable, unless explicitly stated otherwise.
[0046] Measurements and values disclosed herein are considered subject to modification by the term "about," intended to encompass deviations within a range extending approximately ±10% of the stated value, unless a different range is explicitly specified.
[0047] The development of the present invention stems from the need to address the substantial deficiencies or disadvantages observed in conventional self-cleaning filtration assemblies. Existing devices have consistently demonstrated an inability to effectively clean filter elements, resulting in enduring and problematic restrictions on airflow. Despite attempts to adjust cleaning pulses or increase applied pressure, the conventional systems do not achieve a satisfactory reduction in filtration resistance. The persistent inefficacy undermines the operational performance and longevity of the conventional self-cleaning air filter systems/assemblies.
[0048] The self-cleaning air filter assembly of the present invention eliminates or mitigates the limitations and disadvantages of conventional designs, ensuring thorough cleaning and reducing particulate buildup. By enhancing the efficiency of the cleaning process, the present invention attempts to address the issues of residual contamination and airflow restriction, thereby improving the overall effectiveness of the filtration assembly. The invention improves performance and extends filter lifespan across various applications compared to existing technologies.
[0049] The present invention is now described with reference to the accompanying drawing, wherein FIG. 1 illustrates a schematic cross-sectional view of a self-cleaning air filter assembly in accordance with the embodiments of the present invention, FIG. 2 illustrates a schematic cross-sectional view of a tube with nozzles in accordance with the embodiments of the present invention, and FIG. 3 illustrates a schematic cross-sectional view of a nozzle in accordance with the embodiments of the present invention.
[0050] The self-cleaning air filter assembly comprises a cylindrical housing (10) with a closed first end (11) and a closed second end (12), encased by a cylindrical wall (13). The first end (11) receives a first cover plate (14) having a central opening (15), whereas the second end (12) receives a second cover plate (16) thereon. The cover plates (14, 16) may include one or more sealing members positioned between the inner surface of the cover plates and the cylindrical wall edge. In some embodiments, the cover plates may be integral with the cylindrical wall (13). In some other embodiments, the cover plates may be non-integral and may be fastened to the edges of the cylindrical wall (13) using fasteners or by welding. Inside the housing, a cylindrical, annular pleated filter element (20) is positioned concentrically. The filter element (20) features an annular pleated filter media wall (21), a first end plate (22) with a central aperture (23) affixed to one end of the filter media wall (21), and a closed second end plate (24) affixed to the other end of the filter media wall (21). An annular gap (30) is maintained between the outer surface of the filter element (20) and the inner surface of the cylindrical wall (13), forming the dirty side of the air filter assembly. The filter element (20) encloses an interior space (40), creating the clean side of the assembly. Air is drawn into the annular gap (30) through an air inlet port (50) on the cylindrical wall (13), while separated dust is expelled through a dust outlet port (60). The air laden with dust enters the filter media, wherein dust is stopped by the filter media and clean air, or the filtered air is allowed to enter the interior space (40). Filtered air exits the assembly through a clean air outlet port (25), configured on the first cover plate (14), which is in fluid communication with the interior space (40) and aligns with the central aperture (23) of the first end plate (22).
[0051] Further, a tube (70), positioned along the longitudinal axis of the filter element (20) within the interior space (40), is equipped with a plurality of holes, wherein each hole is connected to a nozzle (80), which extends from the surface of the tube (70) in an operative upward direction. The tube (70) is connected to a source of pressurized gas or pressurized air, which is used to pump gas or through the tube (70) and nozzles (80) onto the inner periphery of the annular pleated filter media wall (21) to effectuate cleaning of the filter element (20).
[0052] The nozzle (80) features a body (83), a first proximal end (81) and a distal free end (82). The distal free end (82) is chamfered with a chamfer angle (φ) ranging from 15° to 70°. Preferably, the angle (φ) is in the range of 35° to 55°. In one embodiment, the angle (φ) is 45°.
[0053] The nozzles (80) may be connected to the tube integrally or non-integrally. In some embodiments, the nozzles (80) may be welded to the tube (70). In some other embodiments, the nozzles (80) may be extending from the tube in an integral way and may be manufactured by casting or similar techniques. In cases when the nozzles (80) are non-integral, the tube may be provided with engaging means, and the nozzles (80) may have complimentary engaging means, wherein the engaging means on the nozzle engages with the complimentary engaging means on the tube. In specific embodiments, the engaging means may include threads provided on both the tube and the nozzles. In other embodiments, the engaging means may be of a snap-fit type. In still other embodiments, the engaging means may be of a bayonet type.
[0054] The cylindrical housing (10), made of materials like stainless steel, polypropylene, or plastic, features closed ends (11, 12) and cover plates (14, 16) to ensure structural integrity and an airtight seal. The cylindrical wall (13) encases the filter element, providing support and protection.
[0055] Inside the housing, the annular pleated filter element (20) is positioned concentrically. Made of pleated paper or synthetic fibers, the filter media forms an annular wall (21) that captures dust or contaminants and is secured by the first end plate (22) with a central aperture (23) for clean air exit. The closed second end plate (24) completes the assembly of the annular pleated filter element (20) by sealing the other end of the filter media wall.
[0056] The annular gap (30) between the outer surface of the filter element and the cylindrical wall facilitates the flow of unfiltered air. The interior space (40) within the filter element allows clean air collection, directing it through the clean air outlet port (25), which aligns with the central aperture (23).
[0057] Air enters the assembly through the air inlet port (50) on the cylindrical wall (13) and the separated dust and debris exits through the dust outlet port (60), whereas the filtered air passes through the filter media into the interior space (40). An active suction may be applied to the dust outlet port (60) which facilitates in removing the dust and debris from the annular space (30).
[0058] To clean the filter element, the tube (70), positioned along the longitudinal axis within the interior space (40), is equipped with a series of holes, wherein each hole is connected to the nozzle (80), which has a chamfered second free end (82). The chamfer having an angle (φ) in the range of 15° and 70°. The tube (70) is connected to a source of pressurized gas, which pumps gas through the tube and nozzles to clean the filter media.
[0059] The design of each nozzle within the self-cleaning air filter assembly features a specific length-to-diameter ratio, set in the range of 2:1 and 5:1. The ratio dictates that the nozzle's length is greater than its diameter, a configuration that influences how the pressurized gas is dispersed. By maintaining the proportion, the nozzles are able to direct the gas more effectively across the filter media wall. The elongated design of the nozzles ensures that the cleaning pulses are thoroughly applied to the inner surface or periphery of the filter element, allowing a more efficient removal of accumulated particulates. The precise nozzle design, as discussed herein, enhances the overall performance of the filter, ensuring a more uniform and effective cleaning process.
[0060] The self-cleaning air filter assembly includes nozzles designed with a specific feature in their construction—the chamfered shape. The chamfer (84), which is the beveled edge at the nozzle's end, is defined by a particular length-to-nozzle length ratio. The ratio is set in the range of 1:10 and 1:5, meaning the chamfer's length is proportionately smaller compared to the overall length of the nozzle. The design aspect influences the way the pressurized gas exits the nozzle and interacts with the filter media. The carefully calculated chamfer length allows a focused and controlled flow of air, enhancing the efficiency of particulate removal from the filter media. By refining the shape and size of the chamfer, the design ensures that the cleaning process is both effective and gentle, minimizing the risk of damage to the filter media while maximizing the removal of contaminants. The nozzle's design parameters helps achieve a balanced and effective cleaning action throughout the filter assembly.
[0061] In some embodiments, the tube features a specific length-to-diameter ratio ranging from 8:1 to 16:1. The ratio signifies that the tube's length is considerably longer in comparison to its diameter, a design choice that directly influences the performance and functionality of the assembly. The elongated nature of the tube, relative to its narrow diameter, facilitates a more efficient and uniform distribution of pressurized gas along its entire length. As the gas flows through the tube, it is expelled through multiple holes, each connected to the nozzle. The design ensures that the pressurized gas is delivered evenly across the filter media, enhancing the cleaning process. The extended tube length enables proper spacing of multiple nozzles along its axis, ensuring full coverage of the filter media surface. The tube’s dimensions are designed to enhance the self-cleaning function, ensuring consistent removal of dust and contaminants while preserving the filter element’s performance and durability.
[0062] The self-cleaning air filter assembly is designed with a specific arrangement concerning the positioning of the nozzles relative to the inner surface of the filter media wall. The distance between each nozzle and the inner periphery of the annular pleated filter media wall is carefully calibrated to fall within a range of 15% to 50% of the diameter of the interior space. The spacing impacts the effectiveness of the cleaning process. The selected distance ensures that the pressurized gas, released from the nozzles, reaches the filter media with sufficient force, and spread to dislodge particulates efficiently. By maintaining the specific range, the design avoids the pitfalls of either excessive force, which could damage the filter media, or insufficient force, which could lead to incomplete cleaning. The balanced and calculated spacing allows optimal coverage and penetration of the cleaning gas, ensuring that both large debris and fine particles are effectively removed. The result is a more thorough cleaning process, which enhances the overall efficiency and lifespan of the filter assembly by maintaining its ability to filter air effectively without causing undue wear on the filter media.
[0063] In the self-cleaning air filter assembly, the nozzles are arranged with a specific angular spacing to ensure optimal distribution of cleaning gas across the filter media. The arrangement requires that the angle (ϑ) between adjacent nozzles, measured from the center of the tube, falls within a range of 22.5 to 90 degrees. The configuration is critical for achieving uniform cleaning coverage. The angular spacing allows the pressurized gas to be directed in a manner that maximizes the impact on the filter media surface. By carefully selecting the angle, the design ensures that the cleaning pulses overlap and cover the entire surface area of the filter media, preventing any sections from being missed. The spacing aids in maintaining the efficiency of the cleaning process, as it ensures that each area of the filter receives sufficient attention to dislodge and remove trapped particulates. Furthermore, the arrangement of the nozzles helps in managing the flow dynamics of the pressurized gas, preventing the concentration of force on any single point which could otherwise lead to damage or uneven wear of the filter media. Overall, the nozzle placement enhances the effectiveness of the self-cleaning air filter assembly of the present invention, contributing to the longevity and consistent performance of the air filter assembly.
[0064] In the self-cleaning air filter assembly, the position of nozzles along the length of the central tube affects the cleaning efficiency. In particular, the spacing between two adjacent nozzles may be maintained in the range of 15% and 25% of the tube's length, ensuring that the nozzles are neither too close together nor too far apart. The aforementioned spacing enables achieving a uniform distribution of the pressurized cleaning gas over the entire filter media. The specific positioning of the nozzles ensures that each section of the filter media receives an adequate and consistent blast of cleaning gas, effectively removing accumulated dust and particulates. Further, creation of blind spots is prevented. The distribution of the nozzles also helps to balance the pressure exerted on the filter media, preventing excessive force that could potentially damage the filter. Consequently, the aforementioned way of nozzle spacing contributes to the durability and longevity of the self-cleaning air filter assembly, ensuring reliable performance under various operating conditions.
[0065] In the self-cleaning air filter assembly, the central tube, which serves as a conduit for the pressurized cleaning gas, is securely positioned within the interior space of the filter element. The securement is achieved using fixtures, butterfly bolts, or regular bolts (100), which are placed to hold the tube in position. The fixtures are designed to maintain the tube's stability and alignment along the longitudinal axis of the filter element. By securing the tube firmly, the design ensures that the nozzles, attached along the tube, remain correctly oriented and positioned relative to the filter media. The stability ensures consistent and effective operation of the self-cleaning air filter assembly, as any movement or misalignment of the tube could disrupt the precise delivery of cleaning gas to the filter media. The use of fixtures or butterfly bolts (100) not only provides structural integrity but also facilitates easy installation and maintenance of the self-cleaning air filter assembly.
[0066] The self-cleaning air filter assembly is equipped with the source of pressurized gas or pressurize air (not shown in the figure). In one embodiment, the source is calibrated to supply gas at a pressure in the range of 4 bar to 6 bar. The chosen pressure range enables effective operation of the self-cleaning air filter assembly. The pressure is chosen so that the gas is forcefully expelled through the nozzles, directed towards the filter media to dislodge accumulated particulates. The pressure is high enough to ensure thorough cleaning by effectively removing both fine and coarse particles adhered to the filter surface. However, it is also controlled to avoid causing any damage to the filter media, ensuring that the integrity of the filter element is preserved during repeated cleaning cycles. The specified pressure range balances the need for efficient particulate removal with the longevity and durability of the filter media, allowing the assembly to operate effectively over a prolonged period. The consideration of the pressure ranges ensures that the air filter assembly not only performs its filtration function optimally but also minimizes maintenance requirements and operational disruptions, providing a reliable and efficient solution for maintaining air quality in various applications.
[0067] The pressure range given herein above is exemplary and the pressure range and/or the operating pressure at which the pulses of air or gas are delivered into the tube and through the nozzles may depend on various factors including but not limited to dimensions and geometry of the air filter assembly, the operating conditions of the filter, the restriction before cleaning etc.
[0068] The self-cleaning air filter assembly features nozzles designed with particular attention to their cross-sectional shape. The nozzles may be designed in either a circular or rectangular cross-sectional shape, each offering distinct advantages for the cleaning process. The circular nozzles provide a uniform distribution of pressurized gas, ideal for achieving a consistent cleaning effect over the entire filter media. The circular nozzle ensures that the gas is evenly dispersed, minimizing the risk of uneven cleaning or missing areas. On the other hand, rectangular nozzles may be used to direct the cleaning gas in a more controlled and targeted manner. The rectangular nozzle shape allows a more focused application of pressure, which may be particularly useful in removing stubborn contaminants or in areas of the filter media that require more intensive cleaning. The option to choose between circular and rectangular cross-sectional shapes offers flexibility in the design and application of the cleaning assembly, enabling it to be tailored to specific filtration needs and conditions. The above-mentioned design choice enhances the versatility and efficiency of the air filter assembly, ensuring that it can effectively handle various types of contaminants and operating environments.
[0069] In a working configuration, the self-cleaning air filter assembly operates in a systematic and efficient manner to provide optimal air filtration and maintenance. Initially, dirty air is drawn through the air inlet port (50) into the annular gap (30) surrounding the filter element (20). The air passes through the pleated filter media wall (21), where particles and debris are trapped, allowing clean air to enter the interior space (40) or the clean side of the filter. The cleaned air then flows through the aperture (23) in the first end plate (22). The filtered air exits through the clean air outlet port (25), ready to be used by the engine or equipment.
[0070] As particulates accumulate on the outer surface of the filter media wall (21), the pressure drop across the filter element (20) increases. When the pressure drop reaches a predetermined level, the cleaning mode is activated. The cleaning mode may be activated manually or automatically using suitable circuitry, and mechanisms. Compressed air pulses are introduced through the tube (70), which is connected to the source of pressurized gas. The compressed air flows through the holes in the tube (70) and is expelled through the nozzles (80), which are strategically positioned and have the chamfered exit to spread the air across the filter surface (as described herein above).
[0071] The nozzles (80) are designed to direct the air pulses in a manner that effectively dislodges the accumulated particulates from the filter media wall (21). The dislodged particles are then expelled from the assembly through the dust outlet port (60), located on the cylindrical wall (13) of the housing (10). The cleaning process is conducted without interrupting the main air filtration, allowing continuous operation of the engine or equipment.
WORKING EXAMPLE 1: ENHANCED DUST REMOVAL EFFICIENCY
[0072] An air filter assembly was constructed in accordance with the embodiments of the present invention as described herein. The assembly included a cylindrical housing (10) containing a cylindrical, annular pleated filter element (20). The assembly was set up in a controlled environment to evaluate its dust removal efficiency. Dusty air was introduced through the air inlet port (50) and filtered through the assembly. Once the filter restriction increased significantly, compressed air pulses were supplied through the tube (70) and nozzles (80) at a pressure of 5 bar. Two scenarios were tested: Without nozzles: conventional self-cleaning air filter assembly without nozzles and self-cleaning air filter assembly with nozzles in accordance with the embodiments of the present invention.
[0073] A predetermined amount of dust was fed into the assembly for each scenario. The restriction values before and after cleaning, along with the amount of dust removed, were measured, and recorded.
Table 1: Comparison of Dust Removal Efficiency*
Scenario Dust Fed Restriction After Cleaning Dust Removed
Without Nozzles 1 1 1
With Nozzles 1 0.32 3.8
*The values herein above are normalized.

Table 2: Design Specifications of the Air Filter Assembly
Parameter Value
Tube (70) length-to-diameter ratio 12:1
Nozzle (80) length-to-diameter ratio 3:1
Nozzle chamfer angle 45°
Distance between nozzles 20% of tube length
Angle between adjacent nozzles 45°
Distance between nozzle and filter media 30% of interior space diameter
[0074] The results demonstrate significant improvements in both dust removal efficiency and filter restriction reduction when using the nozzle-based self-cleaning air filter assembly of the present invention. Specifically:
a. Dust Removal: The assembly with nozzles removed 3.8 times more dust compared to the assembly without nozzles.
b. Filter Restriction: After cleaning, the assembly with nozzles reduced the filter restriction to 32% of the level observed in the assembly without nozzles. This represents a 68% reduction in filter restriction.
[0075] These findings indicate that the nozzle-based self-cleaning air filter assembly of the present invention substantially enhances the assembly's overall performance, achieving superior dust removal while significantly lowering filter restriction.
[0076] This example clearly illustrates the enhanced dust dislodgment efficiency of the invented self-cleaning air filter assembly. The nozzle-based design effectively removed nearly four times more dust and resulted in a filter restriction approximately one-third of that observed without nozzles. These improvements contribute to extended filter life, reduced maintenance requirements, and improved overall assembly performance.
TECHNICAL AND ECONOMIC ADVANTAGES OF THE PRESENT INVENTION
TECHNICAL ADVANTAGES
[0077] Continuous Operation: The assembly allows for cleaning cycles without interrupting the main filtration process, even when the engine is running. This ensures constant air filtration and protection.
[0078] Efficient Cleaning: The specially designed nozzles with chamfered ends (angle range 15° to 70°) and strategic positioning ensure uniform and thorough cleaning across the entire filter surface, effectively removing both large debris and fine particles.
[0079] Optimized Nozzle and Tube Design: The specific length-to-diameter ratios of the nozzles (2:1 to 5:1) and tube (8:1 to 16:1), along with the calculated spacing between nozzles, contribute to enhanced cleaning effectiveness and uniform distribution of cleaning air pulses.
[0080] Adaptable Pressure Range: The assembly is designed to operate with a pressurized gas source supplying air at 4 to 6 bars, allowing for effective cleaning without damaging the filter media.
ECONOMIC ADVANTAGES
[0081] Reduced Maintenance Costs: By extending the operational life of the filter element through efficient self-cleaning, the invention minimizes the need for frequent filter replacements, thereby reducing maintenance expenses.
[0082] Decreased Downtime: The continuous operation capability means less frequent stops for filter maintenance or replacement, leading to increased productivity and reduced operational disruptions.
[0083] Improved Fuel Efficiency: By maintaining a consistently clean filter, the assembly helps ensure optimal airflow to the engine, potentially improving fuel efficiency and overall engine performance.
[0084] Longevity in Harsh Environments: The effective self-cleaning air filter assembly of the present invention allows the filter to maintain performance even in high-dust environments, potentially reducing the total cost of ownership for equipment operating in challenging conditions. , C , Claims:We claim:
1. A self-cleaning air filter assembly (1) comprising:
• a cylindrical housing (10) defined by a first end (11), a second end (12), and a cylindrical wall (13) enclosing a space therein, wherein the first end (11) is closed by a first cover plate (14) having an opening (15), and the second end (12) is closed by a second cover plate (16);
• a cylindrical, annular pleated filter element (20) received within the space in the housing (10) in a concentric manner, the filter element (20) comprising:
o an annular pleated filter media wall (21),
o a first end plate (22)
 coupled to a first end of the filter media wall (21), and
 having a central aperture (23), and
o a closed second end plate (24) coupled to a second end of the filter media wall (21);
• wherein an annular gap (30) is maintained between an outer surface of the annular pleated filter element (20) and an inner surface of the cylindrical wall (13), forming a dirty side of the air filter assembly;
• wherein the annular pleated filter element (20) encloses an interior space (40), forming a clean side of the air filter assembly;
• an air inlet port (50) configured on the cylindrical wall (13) for receiving air to be cleaned into the annular gap (30);
• a dust outlet port (60) configured on the cylindrical wall (13) for expelling separated dust;
• a clean air outlet port (25), configured on the first cover plate (14), in fluid communication with the interior space (40) and registering with the central aperture (23) of the first end plate (22), allowing filtered air to exit the assembly;
• a tube (70) received in the interior space (40) and placed along a longitudinal axis of the annular pleated filter element (20), the tube (70) having a plurality of holes;
• a plurality of nozzles (80), each nozzle coupled to one of the plurality of holes in the tube (70), wherein each nozzle (80) comprising:
o a body (83) comprising a hollow tube terminating in a first end (81) coupled to the tube (70) and a second free end (82) terminating in a chamfer (84) having an angle, wherein the chamfer angle is in the range of 15 to 70;
• wherein the tube (70) is connected to a source of pressurized gas ; and
• wherein the pressurized gas is configured to be pumped through the tube (70) and nozzles (80) onto an inner periphery of the annular pleated filter media wall (21) for cleaning the filter element (20).
2. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein each nozzle (80) has a length-to-diameter ratio in the range of 2:1 to 5:1.
3. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the chamfered shape of each nozzle (80) has a chamfer length-to-nozzle length ratio in the range of 1:10 to 1:5.
4. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the tube (70) has a length-to-diameter ratio in the range of 8:1 to 16:1.
5. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the distance between each nozzle (80) and the inner periphery of the annular pleated filter media wall (21) is in the range of 15% to 50% of the diameter of the interior space (40).
6. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the angle between adjacent nozzles, measured from the center of the tube (70), is in the range of 22.5 to 90 degrees.
7. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the distance between adjacent nozzles (80) along the length of the tube (70) is in the range of 15% to 25% of the length of the tube (70).
8. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the tube (70) is held in the interior space (40) using fixtures or butterfly bolts (100).
9. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein the source of pressurized gas is configured to supply gas at a pressure in the range of 4 bar to 6 bar.
10. The self-cleaning air filter assembly (1) as claimed in claim 1, wherein each nozzle (80) has a cross-sectional shape selected from the group consisting of circular and rectangular.
Dated this 02 October 2024
For the Applicant: Fleetguard Filters Private Limited

Deepak Pradeep Thakur
Applicant’s Patent Agent
Reg. No. IN/PA – 3687
To,
The Controller of Patents,
The Patent Office,
At Mumbai