Title of Invention

"A FUEL FILTER COALESCER ELEMENT FOR GROUND AVIATION FUEL HANDLING EQUIPMENT"

Abstract

This invention relates to a filter coalescer cartridge (10) for filtration of aviation fuel comprising a centrally located inner perforated tube (2) provided in the downstream or dirty side with respect of the flow of fuel; a pleated filtration element pack (3) comprising a first filtration media 3 (a) and second filtration media 3(b) supported on said perforated tube (2) for removal of solid contaminants present in said fuel and for initiating the process of coalescing; a perforated retainer (4) supported on said first pleated filtration media (3); an outer filtration media (5) wrapped around said retainer (4) for continuing the process of coalescing; a wrapping (6) around said filtration media (5) for improving water retention and structural strength properties; end caps (1) at either end of said cartridge (10) wit gaskets or (9) or seals held to said end caps (1).

Full Text

FIELD OF INVENTION The present invention relates to fuel filter coalescer element for ground aviation fuel handling equipment. More particularly, the present invention relates to improved aviation fuel filter for providing cleaner fuel to aircrafts. The improved coalescer fuel filter element of the to provide cleaner fuel to the level of 98% efficiency for one-micron size contaminant for defense and civil aviation aircrafts. PRIOR ART Coalescers and separator elements provide aviation turbine fuel, which is free from contamination in the form of sediment and water to an aircraft, and are known in the art. Thus, Patent no. US 6569330 teaches a double-layered filtratlon media pleated with diamond shaped plastic net and wire mesh of 15-30-mesh size to improve the contaminant holding capacity. However this design does not address the filtration efficiency improvement, which is necessary to provide clean fuel for safe flying of aircraft. Another limitation of this design is low filtration efficiency due to bypass of fuel from filter seal and cap. Patent no. GB892663 discloses coalescing or water droplets with open cell plastic foam material by emulsion breaking action of the paper. However in this design water coalescing properties do improve but filtration efficiency and contaminant holding capacity does not improve. Another disadvantage due with this design is that it is commercially not used for air craft fuel filtration as compatibility of foam with aviation turbine fuel is poor and its chances of migrating in to system are quite high. Patent no. GB1107607 discloses coalescing with metal screen coated with polytetrafluoroethylene in a common housing so that fuel reaches the outlet and water is held back by screen. However particulate cleaning and coalescing of water is done in a different designed housing which is more suitable for commercial vehicle segment than aviation. Another disadvantage of this design is that it improves coalescing of water but neither the contaminant holding capacity of filter nor the filtration efficiency. It is recognized in the art that aircrafts require a fuel which should be free from contamination to a very high degree and also free from dissolved water, micro organisms and surfactants. Free and dissolved water helps in growth of microorganisms like fungi etc in the fuel, which contaminates the fuel and is unsafe. Solid contaminants result in faster wear out of engine parts as well as result in blocking the inlet port to restrict the fuel supply to make the aircraft unsafe. Coalescers and separator elements provide aviation turbine fuel, which is free from contamination in the form of sediment and water to an aircraft, and are known in the art. OBJECTS OF THE INVENTION An object of this invention is to propose an improved construction of a filter coalescer cartridge for filtration of aviation fuel. Another object of this invention is to propose a filter coalescer cartridge having improved filteration properties. Still another object of this invention is to propose a filter coalescer cartridge having the required strength properties. Yet another object of this invention is to propose a filter coalescer cartridge which is efficient to a very high degree. STATEMENT OF INVENTION According to this invention there is provided a filter coalescer cartridge for filtration of aviation fuel comprising: (a) a centrally located inner perforated tube provided in the downstream or dirty side with respect to the flow of fuel; (b) a pleated filtration element pack supported on said perforated tube for removal of solid contaminants present in said fuel and for initiating the process of coalescing; (c) a perforated retainer supported on said first pleated filtration media; (d) an outer filtration media wrapped around said retainer for continuing the process of coalescing; (e) a wrapping around said filtration media for improving water retention and structural strength properties; (f) end caps at either end of said cartridge with gaskets or seals held to said end caps. DESCRIPTION OF FIGURES Further objects and advantages of this invention will be more apparent from the ensuing description which read in conjunction with the accompanying drawings and wherein: Fig.l: shows the filter coalescer cartridge of the present invention; Fig.2: shows a plan view of the filter coalescer cartridge; Fig.3: shows the end caps of the filter coalescer cartridge. DESCRIPTION W.R.T. ACCOMPANING DRAWINGS Referring to the drawings and with particular reference to figs. 1 and 2, the filter coalescer cartridge (10) of the present invention comprises an inner perforated tube (2) provided downstream with respect to the flow of fuel. Perforated tube (2) is provided along the entire axial length of the cartridge and forms a support for the filtration media, A pleated element pack (3) is supported on perforated tube (2). The primary function of pleated pack (3) is to capture solid contaminants present in aviation fuel. However, pleated pack (3) also initiates the function of coalescing. In accordance with this invention, element pack (3) comprises a first filtration media (3a) of a sheet of cellulose blended with a Synthetic material, such as polyester and present in an amount of 25 to 40% by weight. If less then 25% by weight of polyester is present, the holding capacity of the pack reduces. First filtration media (3a) comprises a 3 to 4 micron media having higher pore volume for better contaminant holding capacity and improved filtration. Thus, the 6 to 8 micron media of the known art has been reduced to 3 to 4 micron media. Normally, it would be expected that the holding capacity of a 3 to 4 micron media would reduce compared to the known 6 to 8 micron media. Thus, if 'x' is the holding capacity of a 6 to 8 micron media, x/2 would be the holding capacity of a 3 to 4 micron media. However, in accordance with this invention, the same holding capacity of. 'x' is achieved by using thin fibers and whereby the number of pores per unit area increases. Thus, in a 3 to 4 micron media, the number of pores is 4.5 to 5.5 lacs/cm2. In the instance of 6 to 8 micron media, and using the same thin fibers of the present invention, the number of pores is 2 to 2.75 lacs/cm2. Though reference is made to 3 to 4 micron media, it is also possible to use a 6 to 8 micron media. It is known that cellulose has water absorbing properties. As pleated element pack 3 is provided downstream or the dirty side of the filter cartridge, it is exposed to water that may be entrained in the aviation Fuel. Such an exposure to water results in a swelling of the media, and thereby reducing the size of the pores. To prevent such a swelling action of the cellulose media, first filtration media {3a) is impregnated with phenolic resin and, thereafter, provided with a coating of silicon. Such an impregnation and coating imparts strength and water resistant properties. Element pack (3) further comprises a second pleated filtration media (3b) and as shown in Fig.2. Second filtration media (3b) is of HEPA and of 0.3 to 0.5 microns. Filter coalescer cartridge (10) further comprises an outer retainer (4) embracing first pleated element pack (3). Retainer (4) may be made of stainless steel and has a plurality of spaced perforations. Retainer (4) does to a limited extent also assist in the filtration properties, the main function being a support for outer filter media (5). Outer filter media 5 is wrapped on retainer (4). The function of filter media (5) is to continue the water coalescence process initiated by first element media (3). The outer filtration media (5) is no longer in a pleated formation, but in the form of a sheet of 0.25 to 1 micron high efficiency micro glass fiber having hydrophobic properties so as to emulsify water present in aviation fuel to attain improved better water coalescing properties. In order to improve the coalescing properties, outer filtration media 5 is composed of 7 to 8 micron glass fiber media with a glass content of more than 90 to per better coalescing properties. Further 6 to 9 wraps are provided of filtration media 5. The cartridge 10 of the present invention further comprises a mesh 6 composed of Teflon coated glass fibre mesh wrapped with overlap over filtration media 5. Mesh 6 has 40 to 70% area overlapped. It has been found that the presence of such a mesh improves the water repulsion and structural strength properties. Coalescer cartridge (10) further comprises a stocking covering (7). Sealing gasket (9) is held to end caps (1) by epoxy adhesive (9). However, gaskets (9) are directly vulcanited to end caps 1, said epoxy adhesive being a cyno acrylic adhesive. PERFORMANCE TEST FOR COALESCER ELEMENT & SEPARATOR ELEMENT TEST SPECIFICATIONS : API 1581(FIFTH ADDITION) Target conductivity 230+/- lOpS/m Temperature: 28°C System Conditionin|f & Media Migration Check (Table Removed) Continnons Samples; No fibers seen in efiQuent. Water Removal (a) 0.01% of Rated Flow Rate for 30 min. (Table Removed) NOTE: s/s indicates the samples taken just after start, stop procedure. Solid Holding & Removal & Efficiency hv Particle Counter Target Conductivity Solid Addn. Rate Type of SoUd 230 ± lOps/m : 19mg/liter/min. : 10% Copper as Red Oxide R-9998 and 90% Al Ulrafme Test Dust ISO-12103-1 Temperature: 28°C (Table Removed) PARTICULATE EFFICIENCY OBSERVATIONS (Table Removed) Water Removal (a), 0.01% of Rated Flow Rate for 150 mins. (Table Removed) It is to be understood that the system of present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such modifications, changes and adaptations are intended to be within the scope of the present invention, which is further set forth under the following claims: We Claim 1. A filter coalescer cartridge (10) for filtration of aviation fuel comprising:- a) a centrally located inner perforated tube (2) provided in the downstream or dirty side with respect of the flow of fuel; b) a pleated filtration element pack (3) comprising a first filtration media 3 (a) and second filtration media 3(b) supported on said perforated tube (2) for removal of solid contaminants present in said fuel and for initiating the process of coalescing; c) a perforated retainer (4) supported on said first pleated filtration media (3); d) an outer filtration media (5) wrapped around said retainer (4) for continuing the process of coalescing; e) a wrapping (6) around said filtration media (5) for improving water retention and structural strength properties; f) end caps (1) at either end of said cartridge (10) with gaskets or (9) or seals held to said end caps (1). 2. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 1 wherein said second filtration media 3 (b) is formed of cellulose blended with polyester. 3. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 2 comprising 25 to 40% of polyester in said blend. 4. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claims 2 & 3 comprising 2 to 5.51acs of pores for cm2. 5. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 1 wherein said first filtration media 3(a) comprises 3 to 4 microns. 6. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claims 1 to 5 wherein said first filtration media 3 (a) is impregnated with phenotic resin and has a coating of silicon. 7. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 2 wherein said second filtration media 3 (b) is of Hepa. 8. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 1 and 2 wherein said second filtration media 3 (b) comprises micro glass fibers. 9. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 8 comprising to 6 to 9 wraps. 10. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 8 wherein said second filtration media 3 (b) has a glass content of more than 90%. 11. A filter coalescer cartridge (10) for filtration of aviation fuel as claimed in claim 1 wherein said gaskets (9) are directly vulcanized on said end caps (1). 12. A filter coalescer cartridge for filtration of aviation fuel substantially as herein described and illustrated.

Documents:

1332-DEL-2004-Abstract-(24-06-2011).pdf

1332-del-2004-abstract.pdf

1332-DEL-2004-Claims-(24-06-2011).pdf

1332-DEL-2004-Claims-(30-05-2012).pdf

1332-del-2004-claims.pdf

1332-DEL-2004-Correspondence Others-(24-06-2011).pdf

1332-DEL-2004-Correspondence Others-(30-05-2012).pdf

1332-del-2004-correspondence-others.pdf

1332-del-2004-correspondence-po.pdf

1332-del-2004-description (complete).pdf

1332-del-2004-drawings.pdf

1332-DEL-2004-Form-1-(30-05-2012).pdf

1332-del-2004-form-1.pdf

1332-del-2004-form-18.pdf

1332-DEL-2004-Form-2-(30-05-2012).pdf

1332-del-2004-form-2.pdf

1332-DEL-2004-Form-3-(24-06-2011).pdf

1332-DEL-2004-GPA-(24-06-2011).pdf

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