FIELD OF INVENTION:
The present invention relates to a fuel filter system used in internal combustion engine for separating zinc ions and other impurities from the fuel and preventing the nozzles from clogging/ coking.

BACK GROUND OF THE INVENTION:
The main purpose of the filter arrangement is to filter the dirt and rust particles from the fuel. They are normally made into cartridges containing a filter paper. Unfiltered fuel may contain several kinds of contamination, for example paint chips and dirt that has been knocked into the tank while filling. Unfiltered fuel affects the fuel injectors/ nozzles form an intrinsic part of all engines/vehicles.

Technically, large hydrocarbons molecules, fatty acid esters in fuel cause coking, however this phenomenon is substantially enhanced due to the presence of metallic constituents in fuel. Particularly Zinc gets into the fuel by way of plating peel-off, adulterant in fuels in the form of engine oil. Coking basically means, loss of engine power or stoppage, leading to service of nozzles or at times part replacements. It is not possible to remove the entire zinc ions from the fuel by using paper filter/filter element. Various types of filter systems have been used to purify the fuel.

US patent 5,922,199 discloses about a double pass fuel filter assembly (10) has a head portion (12) and an element portion (14) enclosing a replaceable cartridge (18). The assembly has a first inlet port (22) which accepts fuel from a tank (90) and filters it by passage through a screen (43) supported on a tube (36). The fuel that has been filtered by passage through the screen is delivered from the assembly through a first outlet port (24) for delivery to a lift pump (96). Fuel from the lift pump is returned to the fuel filter assembly through a second inlet port (26). The fuel is finely filtered by passage through a loop of filter media (60). Clean fuel is delivered from a second outlet port (28) to an engine (104). Contaminants separated from the fuel by passage through the screen and the media loop are collected in first and second sump areas (78), (80) of the filter housing respectively. An alternative embodiment (110) includes a pre-filter screen (158) integral with a replaceable cartridge (118). The cited patent does not remove the cations from the fuel.

USpatent US 2007/0205147 Al discloses about a liquid filter with directional fluid insert arrangement, the filter assembly for removing particulate contaminants from a fluid, comprises a annular filter element having first and second ends, a filter housing containing the filter element and having first and second ends and a substantially cylindrical side wall defining an annular space between the side wall and the filter element, an end plate secured to the first end of the filter housing and having at least one fluid inlet there through adjacent to the first end of the filter element so that the fluid enters the filter housing through the at least one fluid inlet and flows into the annular space, and a directional fluid insert having at least one of fm disposed between the first end of the filter element and the end plate. The fins provided to cause the fluid entering the filter housing through the at least one fluid inlet to swirl around the filter element.
However all of the above filters are not able to prevent the premature clogging and coking of nozzle essentially due to presence of zinc in the fuel which gets into the fuel by way of plating peel off, adulteration of fuels etc. As such the prior art has not addressed the issue of the zinc removal specifically from the fuel.

To overcome all the drawbacks in the prior art, the present invention discloses a resin bed to improve the fuel filtering efficiency. Therefore the present invention includes a cation exchange resin in the path of fuel to reduce coking significantly.

OBJECT OF THE INVENTION:
1. The first object of the present invention is to exchange the cations with fuel in order to reduce coking tendency in nozzles.
2. The second object of the present invention is to provide an improved fuel filter with easily replaceable resin bed arrangement.

SUMMARY OF THE INVENTION:
The fuel filtering device permits the fuel to pass into the fuel injection pump through the iron exchange bed, which is meshing with the fuel filter element(6). This arrangement is placed inside hollow cylindrical shaped filtration chamber(8).
The inlet fuel flow is diverted through the fuel filter element(6) and resin bed(7) for conducting the ion exchange process. Wherein the resin bed(7) is a cation exchange resin. It can exchange the ions with the fuel.
The above said filter arrangement will remove the maximum quantity of zinc ions and other impurities from the fuel.
The cation exchange resin that may be used is Amberlite IR 120 H, strongly acidic cation exchange resin in Hydrogen form, manufacturer s.d. fine chemicals or combination thereof. The trails were carried out using a constant mass of resign of 25 gm each.

DESCRIPTION OF THE INVENTION:
The invention relates to a fuel filter system. This fuel filter system having a cation exchange resin bed(7) for exchanging the cations such as zinc, chromium and other impurities from the fuel, the fuel filter system protect the nozzle/fuel injectors from clogging/coking. The fuel filter system is placed in the fuel path, prior to the nozzle/fuel injectors.
Now the invention is described with reference to the fig. 1 annexed to the specification.
Fig. 2 illustrates the changes in concentration when using 5% engine oil. Fig. 3 illustrates the changes in concentration when using 10% engine oil.
The fuel filter system includes fuel first set of conventional filter element(6), inlet port(1), outlet port(3) drain screw(9) and the second filter element comprising of resin bed (7). The above components are placed in the cylindrical shaped filtration chamber(8). The hollow cylindrical shaped resin bed(7) is placed in a middle portion of the filtration chamber(8). The resin bed(7) is a combination of cation exchange resins. The resin bed(7) is surrounded by the fuel filter element(6). The whole set is fixed into the filtration chamber(8). The inlet port(1) is mounted on the top of the filtration chamber(8). The inlet port(1) having a curve shaped pipe, one end of the pipe is placed vertically on the fuel filter element(6) for diverting the fuel flow through the fuel filter element(6). The resin bed (7) is a hollow cylinder. The outlet port(3) is connected for collecting the filtered fuel from the hollow portion of the filtration chamber. The above said components are tightly enclosed by the covers, at the top and bottom end of the chamber. A drain screw(9) is connected with a bottom side of the cylindrical shaped filtration chamber(8) through the triangle shaped sachet to collect escaped /drained fuel from the filtration chamber(8).
In fuel filtering process the inlet port(1) diverting the fuel flow through the fuel filter element(6) and resin bed(7). The fuel penetrates the fuel filter element(6) and resin bed(7). The ion exchange process is occurring in the resin bed(7), which exchange/filter the zinc, chromium ions and other impurities from the fuel. In this process maximum amount of impurities are filtered. Finally the filtered fuel reaches the inner side of the resin bed(7) and into the hollow portion of the filtration chamber.
ADVANTAGES OF THE INVENTION:
A predominant nozzle coking elements are zinc, chromium and other impurities. The elements are dislodged from the fuel by ion exchange process thereby minimizing the incidence of nozzle coking.
Cation exchange resin that may be used is Amberlite IR 120 H, strongly acidic cation exchange resin in Hydrogen form, manufacturer s.d. fine chemicals or combination thereof.

WE CLAIMS :-

1. A multistage retrofit fuel filter for delivering filtered fuel to the fuel injection pump comprising :

- a hollow cylindrical filtration chamber having a bottom end and a top end
- a bottom cover disposed on the bottom end of the filter chamber closes the opening on the bottom end of the filtration chamber.
- a top cover disposed on the top end of the filter chamber closes the opening on the top end of the filtration chamber.
- a plurality of nested concentric hollow cylindrical filter members disposed within the filtration chamber forming correspondingly concentric circular first, second and until nth filter members.
- a fuel receiving port disposed on the top cover receiving fuel into said filtration chamber such that fuel to be filtered enters the port and flows radially inwardly through each of the filtering members towards the central hollow portion of the filtration chamber, and
- a fuel delivery port also disposed on the top cover for delivery of a fuel out from the said filtration chamber such that the filter fuel in the hollow portion of the filtration chamber exists out from the fuel delivery port

2. The multistage retrofit fuel filter as claimed in claim 1, wherein the filter elements are cylindrical.

3. The multistage retrofit fuel filter as claimed in claim 1, wherein the first filter elements forms the outer filter element with respect to second filter element.

4. The multistage retrofit fuel filter as claimed in claim 1, wherein the second filter elements forms the outer filter element with respect to first filter element.

5. The multistage retrofit fuel filter as claimed in claim 1, wherein atleast the first filter element is any known filter or filter bed such filter bed elements composed of filter paper.

6. The multistage retrofit fuel filter as claimed in claim 1, wherein atleast the second filter element is ion exchange resin bed.

7. The multistage retrofit fuel filter as claimed in claim 1, wherein atleast second filter element is cation exchange resin bed.

8. The multistage retrofit fuel filter as claimed in claim 1, wherein atleast second filter element is a combination of a cation exchange resin bed.

9. The multistage retrofit fuel filter as claimed in claim 1, wherein the cation exchange resin bed is a single cation exchange resin selected from a group comprising of comprising of a resign formed with Amberlite IR 120 H, or a strongly acidic cation exchange resin in Hydrogen form.

10. The multistage retrofit fuel filter as claimed in claim 1, wherein the cation exchange resin bed is a combination of plurality of cation exchange resin selected from a group comprising of plurality of resin exchange colums formed with Amberlite IR 120 H, or a strongly acidic cation exchange resin in Hydrogen form or combination thereof.

11. The multistage retrofit fuel filter as claimed in claim 1, wherein a drain screw is disposed on the bottom cover to drain fuel from the filtration chamber.