DESC: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
A SPIN-ON FILTER AND A METHOD OF MANUFACTURING THE SAME
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
FLEETGUARD FILTERS PRIVATE LIMITED AN INDIAN COMPANY 136, PARK MARINA ROAD, BANER, PUNE – 411045, MAHARASHTRA, INDIA
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 disclosure pertains to spin-on filters, particularly focusing on a spin-on filter exhibiting significantly enhanced burst strength in comparison to conventional counterparts. Additionally, the disclosure encompasses a method for manufacturing the spin-on filter.
BACKGROUND OF THE INVENTION
[002] Spin-on filters find extensive application across various filtering needs, encompassing but not limited to oil filtration, hydraulic fluid filtration, lubricant fluid filtration, and fuel filtration.
[003] A typical conventional spin-on filter comprises a substantially cylindrical shell with a sealed lower end and an open upper end. This open end accommodates a nut-plate or a cover-plate, with the former securely fastened atop the open end. The nut-plate not only seals the upper end but also facilitates the filter's attachment to a filter head. Within the cylindrical shell resides a filter element, generally comprising annular filter media. This filter element may define a peripheral dirty side and a central annular region serving as the clean side within the shell. The nut-plate features a central opening in fluid communication with the central annular region, allowing cleaned fluid to pass through to a designated utility, such as an engine. Additionally, a series of through holes are strategically positioned on the nut-plate surrounding the central opening, enabling the intake of dirty fluid for filtration into the filter's dirty side.
[004] In conventional designs, the attachment of the nut-plate to the shell typically involves bending the free edge of the shell onto the nut-plate or deforming a section of the shell beneath the nut-plate internally and then bending the shell's free edge onto the upper surface of the nut-plate along its periphery.
[005] However, conventional spin-on filters featuring the aforementioned nut-plate attachment methods exhibit certain drawbacks.
[006] One drawback is the occurrence of leaks or spillage during operation.
[007] Another drawback is the tendency for leaks to develop under high fluid pressures, typically exceeding 50 bar.
[008] Another drawback is that the conventional filters often possess relatively low burst strength.
[009] Therefore, there exists an urgent need for a spin-on filter that addresses the aforementioned drawbacks. Specifically, there is an immediate requirement for a spin-on filter that remains leak-free even under or above 50 bar fluid pressure, has a high burst strength, and can be safely utilized at high pressures.
OBJECTS OF THE INVENTION
[0010] The present disclosure aims to achieve several objects, wherein at least one object is realized by one or more embodiments detailed herein:
[0011] One object of the present disclosure is to offer an alternative solution that mitigates at least one limitation present in the existing prior art.
[0012] Another object is to present a spin-on filter.
[0013] Yet another object is to provide a spin-on filter characterized by high burst strength, typically greater than 50 bar.
[0014] Another object is to provide a spin-on filter capable of maintaining leak-free performance even under high fluid pressures, including those exceeding 50 bar, and reduced and high-pressure cycles.
[0015] Another object is to provide a method of manufacturing the spin-on filter with high burst strength of greater than 50 bar, leak-free performance under high pressures, and leak-free performance under reduced and high-pressure cycles.
[0016] Further objects and advantages of the present disclosure will become evident from the subsequent description, which is not intended to limit the scope of the disclosure.

SUMMARY OF THE INVENTION
[0017] Disclosed is a spin-on filter exhibiting significantly enhanced burst strength in comparison to conventional counterparts and a method for manufacturing the spin-on filter
[0018] In one aspect a spin-on filter is disclosed, wherein the spin-on filter is capable of withstanding a fluid pressure in the range of 50 bar to 120 bar and withstanding a cyclic pressure variation ranging from 0 bar to 35 bar for 1 lakh to 2 lakh cycles.
[0019] The spin-on filter comprises a shell having a bottom end and an open top end, a filter element received within the shell, and a nut-plate having a body. The body is received in the open top end of the shell, wherein the body comprising an upper surface, a lower surface and a peripheral surface, the body having a thickness 'd' at and around the peripheral surface. A first trench having a radius of curvature (R1) is configured on the peripheral surface which being spaced apart from the upper surface, and a second trench having a radius of curvature (R2) is configured on the peripheral surface which is spaced apart from the lower surface and the first trench. In accordance with the embodiments of the present disclosure the radius of curvature (R1) is greater than or equal to the radius of curvature (R2); wherein the spin-on filter is capable of withstanding a fluid pressure in the range of 50 bar to 120 bar and withstanding a cyclic pressure variation ranging from 0 bar to 35 bar for 1 lakh to 2 lakh cycles.
[0020] In accordance with one embodiment of the present disclosure, a third trench is formed on the peripheral surface between the first trench and the second trench, the third trench receiving a sealing member therein, wherein the sealing member is an O-ring or a gasket.
[0021] In accordance with one embodiment of the present disclosure the radius of curvature (R3) of the third trench is less than the radius of curvature (R1), and the radius of curvature (R2), wherein the ratio of the R1 to R3 and R2 to R3 is independently in the range of 0.1 to 10.
[0022] In accordance with one embodiment of the present disclosure, the radius of curvature (R1) is in the range of 1 mm to 10 mm, the radius of curvature (R2) is in the range of 1 mm to 10 mm, the depth of the first trench is in the range of 5 mm to 15 mm, the depth of the second trench is in the range of 5 mm to 15 mm, the thickness of the nut-plate is in the range of 20 mm to 50 mm, the distance between the centres of the first trench, and the second trench is in the range of 10 mm to 100 mm, the distance between the centres of the first trench and the third trench, and the second trench and the third trench is independently in the range of 10 mm to 50 mm, the depth of the third trench is in the range of 2 mm to 10 mm, and the height of the third trench is in the range of 2 mm to 10 mm.
[0023] In accordance with one embodiment of the present disclosure, the first, second, and the third trenches having a cross sectional shape selected from the group consisting of semi-circular, semi-oval, rectangular, square, polygon, and combinations thereof.
[0024] In accordance with another aspect of the present disclosure, a method for manufacturing the spin-on filter is disclosed, wherein the method comprising the steps of forge forming the shell, placing a biasing member is inside the shell, wherein the biasing member rests on the closed end of the shell, placing the filter element on the spring, such that the filter element is supported on the biasing member, placing the nut-plate on an upper end of the filter element, wherein the nut-plate having the first, second, and the third trench configured on the periphery thereof, wherein the sealing member is received in the third trench, and deforming an upper wall portion of the shell wherein the upper wall portion at and around the first and the second trenches being deformed and being received in the first and second trenches, thereby configuring a ring like portions, wherein the third trench which receives the sealing member is sandwiched between the first and the second trenches, and wherein any movement of the nut-plate, whether the movement is rotational and/or up and/or down movement even under high pressure, which may be in the range of 50 bar to 120 bar is avoided.
[0025] In accordance with one embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the first trench is done first, followed by deformation at and around the second trench.
[0026] In accordance with one embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the second trench is done first, followed by deformation at and around the first trench.
[0027] In accordance with one embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done simultaneously.
[0028] In conformity with a specific embodiment delineated herein, the distortion or forming of the shell wall section to complement the profile of the first and second trenches is accomplished by utilizing a forming roller, wherein one or more rollers may be employed to exert pressure on the shell wall section, thereby compelling it to conform to the profiles of the first and second trenches.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[0029] The present disclosure will now be described with the help of the accompanying drawing, in which:
[0030] FIG. 1 illustrates a perspective view of a spin-on filter in accordance with the embodiments of the present disclosure;
[0031] FIG. 2 illustrates a cross-sectional view of the spin-on filter of FIG. 1;
[0032] FIG. 3 illustrates a side view of the spin-on filter of FIG. 1; and
[0033] FIG. 4 illustrates a top view of the spin-on filter of FIG. 1
LIST OF NUMERALS
[0034] The following is a list of numerals employed to indicate various components of the spin-on filter of the present disclosure.
100 – Spin-on filter 106f2 – Lower surface
102 – Shell 106p – Periphery
102a – Open top end 106s – Seal or gasket
102b – Closed bottom end 106t1 – First trench
104 – Filter element 106t2 – Second trench
104a – Pleated filter media 106t3 – Third trench
104b – Top end plate 106O1 – Central Opening
104c – Bottom end plate 106O2 – Plurality of peripheral through holes
106 – Nut-plate 108 – Biasing member
106a – Body
106f1 – Upper surface
DETAILED DESCRIPTION
[0035] Throughout the ensuing description and appended claims, all specialized terminology and technical expressions shall be accorded the meanings conventionally ascribed to them by one skilled in the pertinent art, unless explicitly defined otherwise herein.
[0036] As employed in the present disclosure and the accompanying claims, the singular forms "a," "an," and "the" are intended to encompass plural references, unless the context unambiguously indicates otherwise. Any reference to "one," "a," "an," or "the" should be construed as encompassing both singular and plural forms, unless the context manifestly dictates a contrary interpretation.
[0037] The terms "comprise," "comprises," and "comprising," as utilized in the present disclosure, should be interpreted as being non-limiting and open-ended, allowing for the inclusion of additional suitable elements, including but not limited to one or more additional features, parts, components, process steps, sub-steps, and/or constituents as applicable, unless expressly stated to the contrary.
[0038] Unless otherwise specified, all measurements and values disclosed herein should be interpreted as being modified by the term "about," even if the term "about" is not explicitly employed. The use of the term "about" is intended to encompass deviations within ±10% of the stated value, unless a different range is explicitly delineated.
[0039] The term "substantially" or "essentially," when used in conjunction with a characteristic or property, should be construed as encompassing variations that would be recognized by one skilled in the relevant art as not significantly altering the intended result or performance of the described embodiment.
[0040] The use of the terms "optional" or "optionally" in the description and claims should be interpreted as indicating that the subsequently described element, step, or feature may or may not be included in the scope of the invention, contingent upon the particular embodiment or implementation.
[0041] The use of the term "and/or" between elements in a list is intended to encompass all possible combinations of the listed elements, including both individual elements and combinations of two or more elements, unless the context unambiguously dictates otherwise.
[0042] The use of the phrase "in one embodiment" or similar phrasing does not necessarily refer to the same embodiment, and different occurrences of the phrase may refer to different embodiments or aspects of the invention.
[0043] Any reference to a specific numerical value should be construed as including a range extending from about 10% below the stated value to about 10% above the stated value, unless a different range is explicitly delineated.
[0044] The terms "invention," "present disclosure," and "aspects of the invention" as used herein are intended to encompass all embodiments of the invention, unless the context clearly indicates otherwise.
[0045] The use of the terms "first," "second," "third," and so on, or similar terminology, is solely for the purpose of distinguishing between different elements or components and should not be construed as implying any particular order, sequence, or hierarchy, unless explicitly stated or inferred from the context.
[0046] The terms "coupled," "connected," and "attached," and variations thereof, are used interchangeably throughout the present disclosure and are not intended to be limiting or imply any particular type of connection or attachment, unless the context clearly dictates otherwise.
[0047] The terms "upper," "lower," "top," "bottom," "front," "rear," "side," and the like, are used solely for the purpose of describing the relative positioning or orientation of various elements or components within the embodiments described herein and should not be construed as limiting the invention to any particular orientation or configuration, unless explicitly stated or inferred from the context.
[0048] Any reference to specific materials, compositions, or substances should be interpreted as encompassing both the named materials and their equivalents, unless the context clearly indicates otherwise.
[0049] The use of the term "may" throughout the present disclosure and claims is intended to indicate a possibility or an alternative, but not a requirement or obligation, unless the context clearly dictates otherwise.
[0050] The present disclosure relates to spin-on filters, which exhibit substantially enhanced burst strength in comparison to conventional counterparts. A method for manufacturing the spin-on filter is also disclosed.
[0051] In accordance with one aspect of the present disclosure, a spin-on filter (100) is disclosed. The spin-on filter (100) of the present disclosure comprises a shell (102) having a bottom end (102b) and an open top end (102a). The shell (102) may be made of metal, which may be drawable steel, or any suitable metal. The bottom end (102b) of the shell (102) may be closed without any opening. In some embodiments, the bottom end (102b) may have an aperture formed thereon. The aperture may include a drain valve or similar component which may allow draining of the liquid within the shell. The liquid may be fuel, lubricant, hydraulic fluid, water etc.
[0052] The shell (102) includes an interior space, wherein a filter element (104) received. The filter element (104) may be a pleated filter element (104a) comprising pleated filter media, and end caps (104b, 104c) attached to the ends of the filter media. In some embodiments the filter element (104) may be a spiral type of filter, having filter media in form of spirally wrapped filter paper. Any other type of filter and/or combination of filters is/are well within the ambit of the present disclosure and the present disclosure is not limited to the above-mentioned examples of the filter element.
[0053] The filter element (104) may be directly placed on the bottom end (102b) of shell (102). In an alternative embodiment, the filter element (104) may be placed on a biasing member (108) which is positioned on the bottom end (102b) of the shell (102). The provision of biasing member (108) is known in the art. In one embodiment, the biasing member (108) is a spring.
[0054] Further, the spin-on filter (100) includes a nut-plate (106). The nut plate (106) also known as the cover-plate comprises a body (106a). The nut-plate is received in the open top end (102a) of the shell (102).
[0055] In an embodiment in accordance with the embodiments of the present disclosure, the nut plate (106) may be made of metal, or alloy.
[0056] In accordance with one embodiment of the present disclosure, the nut-plate (106) is having a central hole (106O1) and peripheral holes (106O2) surrounding the central hole (106O1). The central hole (106O1) is in fluid communication with the central clean side, and the peripheral holes (106O2) are in fluid communication with the annular dirty side.
[0057] In accordance with one embodiment of the present disclosure, the body (106a) of the nut plate (106) is defined by and between an upper surface (106f1), a lower surface (106f2), and a peripheral surface (106p) as shown in FIG. 2. The upper surface and the lower surface of the nut plate (106) may be having planar contour or may have any other profile depending on the requirement or application.
[0058] In accordance with one embodiment of the present disclosure, the body (106a) is having a peripheral thickness ‘d’, wherein ‘d’ may range from 10 mm to 50 mm. The thickness of the body (106a) may vary across the diameter thereof. The body (106a) may have a circular disc like shape or any other shape that compliments the inner shape of the shell (102).
[0059] In accordance with the embodiments of the present disclosure, the nut-plate (106) is configured with a first trench (106t1). The word trench herein may include a groove or a pit or any similar formation. The first trench (106t1) is characterized by having a radius of curvature (R1) which is configured on the peripheral surface (106p) of the nut-plate. The first trench (106t1) is spaced apart from the upper surface (106f1) as shown in FIG. 2.
[0060] In accordance with the embodiments of the present disclosure, the nut-plate (106) is configured with a second trench (106t2). The second trench is having a radius of curvature (R2) which is configured on the peripheral surface (106p) and which is spaced apart from the lower surface (106f2) and the first trench (106t1).
[0061] In accordance with the embodiments of the present disclosure, the radius of curvature (R1) of the first trench is greater than or equal to the radius of curvature (R2) of the second trench. This feature of R1 being greater than or equal to R2 provides an advantage which is described below.
[0062] In accordance with one embodiment of the present disclosure, the number of trenches may be increased to more than two. That is the number of trenches formed or configured on the peripheral surface of the nut-plate may be three or four or even more. The number of trenches may depend on the pressure to be handled and also on the size of the spin-on filter. For example, for a small sized spin-on filter wherein the pressure is in the order of 60 bars or more, two trenches may suffice. However, for a large sized spin-on filter, which may be used in hydraulic systems wherein the pressure is high, of the order of 80 bars or more, the number of trenches may be more than two. The present disclosure is not limited by the number of trenches.
[0063] In accordance with the one embodiment of the present disclosure, the ratio of radius of curvature (R1) to the radius of curvature (R2) is in the range of 1 to 20.
[0064] In accordance with the embodiments of the present disclosure, a portion of the shell (102) wall in proximity of the first trench and the second trench is deformed so as to follow the profile of the first trench and the second trench thereby configuring seal between the nut-plate and the shell (102). The provision of the first trench and the second trench with the deformation of the shell wall facilitates in withholding a high pressure as compared to the conventional spin-on filter. Also, the second trench is a kind of sacrificial trench, wherein the deformed shell wall may be dislocated due to the high pressure of the fluid, however due to the provision of the first trench and a sealing member between the first and second trench prevents leakage or early bursting of the spin-on filter.
[0065] In accordance with the one embodiment of the present disclosure, the nut-plate (106) further includes a third trench (106t3) which is formed on the peripheral surface (106p) between the first trench (106t1) and the second trench (106t2). The third trench (106t3) is configured to receiving a sealing member (106s) therein. In one embodiment, the sealing member (106s) is an O-ring. In another embodiment, the sealing member is a gasket. The number of third trenches may be more than one, meaning that, the number of sealing members may be more than one. The sealing member (106s) is provided to prevent leakage of the pressurized fluid from between the shell wall and the peripheral surface of the nut-plate. Again, the number of sealing members may also depend on the size of the spin-on filter, and the operating pressures.
[0066] In accordance with one embodiment of the present disclosure, the radius of curvature (R3) of the third trench (106t3) is less than the radius of curvature (R1), and the radius of curvature (R2).
[0067] In accordance with one embodiment of the present disclosure, the ratio of the R1 to R3 and R2 to R3 is independently in the range of 0.1 to 10.
[0068] In accordance with one exemplary embodiment of the present disclosure, the radius of curvature (R1) is in the range of 1 mm to 10 mm.
[0069] In accordance with one exemplary embodiment of the present disclosure, the radius of curvature (R2) is in the range of 1 mm to 10 mm.
[0070] In accordance with one exemplary embodiment of the present disclosure, the depth of the first trench (106t1) is in the range of 5 mm to 15 mm.
[0071] In accordance with one exemplary embodiment of the present disclosure, the depth of the second trench (106t2) is in the range of 5 mm to 15 mm.
[0072] In accordance with one exemplary embodiment of the present disclosure, the thickness of the nut-plate (106) is in the range of 20 mm to 50 mm.
[0073] In accordance with one exemplary embodiment of the present disclosure, the distance between the centres of the first trench (106t1), and the second trench (106t2) is in the range of 10 mm to 100 mm.
[0074] In accordance with one exemplary embodiment of the present disclosure, the distance between the centres of the first trench (106t1) and the third trench (106t3), and the second trench (106t2) and the third trench (106t3) are independently in the range of 10 mm to 50 mm.
[0075] In accordance with one exemplary embodiment of the present disclosure, the depth of the third trench (106t3) is in the range of 2 mm to 10 mm, and the height of the third trench is in the range of 2 mm to 10 mm.
[0076] In accordance with one embodiment of the present disclosure, the first, second, and the third trenches are each independently having a cross sectional shape selected from the group consisting of semi-circular, semi-oval, rectangular, square, polygon, and combinations thereof.
[0077] In accordance with another aspect of the present disclosure, a method for manufacturing the spin-on filter is disclosed. The method comprises the following steps, which are described herein below in detail.
[0078] In step 1, a shell is formed or drawn by known method. For example, a shell of metal such as mild steel is formed using suitable set of dies. The shell is generally cylindrical in shape. Any other suitable shape is also well within the ambit of the present disclosure and the present disclosure is not limited to shells with cylindrical shape. The unwanted material or edges of the shell are trimmed. Further, the shell may be cleaned further using suitable cleaning agent. The shell is checked for leakages. The shell is so formed that the shell is having an open end and a closed end. In some embodiments, the shell may have a drainage opening at and around the closed end.
[0079] In step 2, a biasing member (108) such as a spring is positioned is inside the shell (102), wherein the biasing member (108) rests on the closed end of the shell (102). The biasing member (108) is having a pre-defined tension depending on the force that is required to urge the filter element, upward direction towards the nut-plate, which is placed above away from the closed end.
[0080] In step 3, a filter element (104) is placed on the spring, such that the filter element is supported on the biasing member (108).
[0081] In step 4, a nut-plate (106) is placed on an upper end of the filter element. The nut-plate (106) employed herein is having three trenches, namely, first, second, and the third trenches configured on the peripheral surface thereof, wherein the sealing member (106s) is received in the third trench.
[0082] In step 5, an upper wall portion of the shell wherein the upper wall portion at and around the first and the second trenches is deformed and is received in the first and second trenches, thereby configuring a ring like portions, wherein the wall portion substantially achieves the shape of the trenches, thereby the third trench which receives the sealing member is sandwiched between the first and the second trenches and any movement of the nut-plate, whether the movement is rotational and/or up and/or down movement even under high pressure, which may be in the range of 50 bar to 120 bar is avoided.
[0083] In accordance with one embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the first trench is done first, followed by deformation at and around the second trench.
[0084] In accordance with another embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the second trench is done first, followed by deformation at and around the first trench.
[0085] In accordance with yet another embodiment of the present disclosure, the deformation of the upper wall portion of the shell at and around the first and the second trenches is done simultaneously.
[0086] In conformity with a specific embodiment delineated herein, the distortion or forming of the shell wall section to complement the profile of the first and second trenches is accomplished by utilizing a forming roller, wherein one or more rollers may be employed to exert pressure on the shell wall section, thereby compelling it to conform to the profiles of the first and second trenches. The deformation or forming of bead which complement the profile of the trench using roller is well known in the art.
[0087] The spin-on filter of the present disclosure is capable of withstanding a fluid pressure in the range of 50 bar to 120 bar, and a cyclic pressure variation ranging from 0 bar to 35 bar for 1 lakh to 2 lakh times.
WORKING CONFIGURATION OF THE SPIN-ON FILTER OF THE PRESENT DISCLOSURE
[0088] The spin-on filter of the present disclosure works in a similar way as that of the conventional spin-on filter. The spin-on filter of the present disclosure is coupled with a filter head, which may include input and output fluid, or liquid lines configured therein. The filter head may be a standard filter head which is well known in the art to which the spin-on filter is coupled for filtering a fluid such as fuel or lubricant.
[0089] The spin-on filter as described in the foregoing detailed exposition is produced using the method delineated herein. It is affixed to a fluid source, which may encompass fuels, lubricants, oils, etc., with the source potentially being an internal combustion engine. The inlet (106O2) links to the incoming line for contaminated fluid, while the outlet (106O1) connects to the clean fluid line exiting the engine. Fluid traverses into the space between the outer perimeter of the filter element and the inner surface of the shell, referred to as the annular region or the so-called 'dirty side' of the filter. Subsequently, the fluid is compelled through the filter element, particularly the filter media, before proceeding to the central interior region of said element. The purified fluid then exits via the central aperture or outlet (106O1) to the engine. Thus, the working of the spin-on filter is almost similar to the conventional filter.
EXAMPLES
[0090] The conventional spin-on filter and the spin-on filter of the present invention were evaluated for burst pressures and the cyclic pressure variations. The conventional spin-on filter had a similar construction as that of the spin-on filter of the present invention but had only one trench and one sealing member, whereas the spin-on filter of the present invention had two trenches (as described herein above) and one sealing member received in the third trench.
[0091] The table 1 herein below lists various dimensions and parameters relating to the conventional spin-on filters and spin-on filters of the present invention, wherein a number of spin-on filters having almost same dimensions were evaluated for burst strength and cyclic pressure variations:
Table 1
Sample Trenches (dimensions in mm) BP PV-NC
FT ST TT S
R1 D1 R2 D2 R3 D3
A 3.5 3.0 NA NA 3.5 2.7 NA 50-65 < 1.0
B 3.5 3.0 3.5 3.0 3.5 2.7 18.5 90 -118 1.0 – 2.0
C 3.5 3.0 3.2 2.8 3.5 2.7 18.5 92-120 1.0 – 1.9
FT – First trench
ST – Second trench
TT – Third trench
A – Conventional spin-on filter
B – Spin-on filter of the present invention
S – Spacing between the first and the second trench
BP – Burst pressure (bar)
PV-NC – Pressure variation from 0-35 bar and number of cycles for which the filter withstood without leaking (number of cycles in multiples of 1 x 105)
Sample – Spin-on filters
[0092] From the above table 1, it is evident that the sample B, which is the spin-on filter of the present invention is capable of withstanding high pressure. More specifically the spin-on filter of the present invention with two trenches formed in the nut-plate (as described herein above), wherein the shell wall is secured at two places at and around the top open end of the shell, the burst pressure is 92 bar, and the number of cycles with pressure variation from 0-35 bar is 1.5 lakhs which is way more as compared to the sample A which is a conventional spin-on filter with a single trench in the nut-plate.
TECHNICAL ADVANTAGES AND ECONOMICAL SIGNIFICANCE OF THE PRESENT INVENTION
[0093] The present invention, i.e., the spin-on filter of the present invention provides numerous technical advantages, wherein the spin-on filter exhibits a high burst strength and can withstand a pressure in the range of 50 bar to 120 bar and can withstand cyclic pressure variations ranging from 0-35 bar for 1,00,000 to 2,00,000 cycles.

,CLAIMS:We claim:
1. A spin-on filter (100) comprising:
- a shell (102) having a bottom end (102b) and an open top end (102a);
- a filter element (104) received within the shell (102);
- a nut-plate (106) having a body (106a) is received in the open top end (102a) of the shell (102), wherein
o the body (106a) comprising an upper surface (106f1), a lower surface (106f2) and a peripheral surface (106p);
o the body (106a) having a thickness ‘d’ at and around the peripheral surface (106p);
characterized in that:
- a first trench (106t1) having a radius of curvature (R1) is configured on the peripheral surface (106p) which being spaced apart from the upper surface (106f1); and
- a second trench (106t2) having a radius of curvature (R2) is configured on the peripheral surface (106p) which is spaced apart from the lower surface (106f2) and the first trench (106t1);
wherein the radius of curvature (R1) is greater than or equal to the radius of curvature (R2);
wherein the spin-on filter is capable of withstanding a fluid pressure in the range of 50 bar to 120 bar;
wherein a portion of the shell (102) in proximity of the first trench and the second trench is deformed so as to follow the profile of the first trench and the second trench thereby configuring seal between the nut-plate and the shell (102); and
wherein the spin-on filter is capable of withstanding a cyclic pressure variation ranging from 0 bar to 35 bar for 1 lakh to 2 lakh times.
2. The spin-on filter (100) as claimed in claim 1, wherein the ratio of radius of curvature (R1) to the radius of curvature (R2) is in the range of 1 to 20.
3. The spin-on filter (100) as claimed in claim 1, wherein a third trench (106t3) is formed on the peripheral surface (106p) between the first trench (106t1) and the second trench (106t2), the third trench (106t3) receiving a sealing member (106s) therein, wherein the sealing member (106s) is an O-ring or a gasket.
4. The spin-on filter (100) as claimed in claim 3, wherein the radius of curvature (R3) of the third trench (106t3) is less than the radius of curvature (R1), and the radius of curvature (R2); wherein the ratio of the R1 to R3 and R2 to R3 is independently in the range of 0.1 to 10.
5. The spin-on filter (100) as claimed in claim 3, wherein the radius of curvature (R1) is in the range of 1 mm to 10 mm, the radius of curvature (R2) is in the range of 1 mm to 10 mm, the depth of the first trench (106t1) is in the range of 5 mm to 15 mm, the depth of the second trench (106t2) is in the range of 5 mm to 15 mm, the thickness of the nut-plate (106) is in the range of 20 mm to 50 mm, the distance between the centres of the first trench (106t1), and the second trench (106t2) is in the range of 10 mm to 100 mm, the distance between the centres of the first trench (106t1) and the third trench (106t3), and the second trench (106t2) and the third trench (106t3) is independently in the range of 10 mm to 50 mm, the depth of the third trench (106t3) is in the range of 2 mm to 10 mm, and the height of the third trench is in the range of 2 mm to 10 mm.
6. The spin-on filter (100) as claimed in claim 3, wherein the first, second, and the third trench having a cross sectional shape selected from the group consisting of semi-circular, semi-oval, rectangular, square, polygon, and combinations thereof.
7. A method for manufacturing the spin-on filter as claimed in claim 3, wherein the method comprising the following steps:
- forge forming the shell (102);
- placing a biasing member (108) is inside the shell (102), wherein the biasing member (108) rests on the closed end of the shell (102);
- placing the filter element (104) on the spring, such that the filter element is supported on the biasing member (108);
- placing the nut-plate (106) on an upper end of the filter element, wherein the nut-plate (106) having the first, second, and the third trench configured on the periphery thereof, wherein the sealing member (106s) is received in the third trench; and
- deforming an upper wall portion of the shell wherein the upper wall portion at and around the first and the second trenches being deformed and being received in the first and second trenches, thereby configuring a ring like portions;
wherein the third trench which receives the sealing member is sandwiched between the first and the second trenches; and
wherein any movement of the nut-plate, whether the movement is rotational and/or up and/or down movement even under high pressure, which may be in the range of 50 bar to 120 bar is avoided.
8. The method for manufacturing the spin-on filter as claimed in claim 7, wherein
- the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the first trench is done first, followed by deformation at and around the second trench; or
- the deformation of the upper wall portion of the shell at and around the first and the second trenches is done sequentially, wherein the deformation at and around the second trench is done first, followed by deformation at and around the first trench; or
- the deformation of the upper wall portion of the shell at and around the first and the second trenches is done simultaneously.
Dated this the 19th day of May 2023
For the Applicant: Fleetguard Filters Private Limited

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