FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:
SELF CLEANING FILTER


APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra . INDIA.

PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to filter cleaning mechanism and particularly to self cleaning filter for liquid dispensers. The present invention more particularly relates to filter cleaning mechanism in self cleaning filter assembly for fuel dispensers.
B) BACKGROUND OF THE INVENTION
[0002] A fuel dispenser is a machine used in filling stations to pump petrol, diesel. kerosene and other types of fuels into vehicles. The fuel dispensers are also known as petrol pumps or gas pumps. The fuel dispenser basically includes a pump, a fuel supply pipe, a flow meter and a fuel supply hose with nozzle and the indicator. The dispenser draws fuel from the underground tank. The fuel dispenser dispenses fuel to vehicle tank through nozzle. During the dispensing of fuel, the hydraulic meter measures accurate amount of the fuel dispensed. The measurement of fuel is conveyed by an electronic or mechanical console. One of the most important functions of the fuel dispensing system is to remove the dust particles in the fuel and to output the filtered fuel to the vehicles through the nozzle.
[0003] A fuel filtration system is generally used in dispensers to remove large particles as well as small debris in the fuel. The solid contaminants such as dirt, rust, and the like, have always been a problem when it occurs in vehicle fuel. The fuels are dispensed directly into vehicle fuel tanks at service stations. However, the problem with fuel contaminants is much more serious due to universal adoption of fuel injection systems for

vehicle engines. A dispensing system usually includes an underground storage tank where fuel is stored in large volumes. The fuel is pumped on demand to an aboveground dispensing unit.
[0004] In the fuel dispensing system the combination pumping unit creates the vacuum pressure and due to this the fuel is sucked from the underground storage tank through pipe lines. The fuel which is sucked from storage tank is not cleaned and hence the filter is provided at the inlet side of the pumping unit for cleaning the fuel. The filter cleans the fuel and prevents damage of sensitive parts in the fuel line. After some period, the filter gets clogged due to the accumulation of the dirt and it affects the performances of the system. As a result, we will not get the desired Liters per Minute (LPM) which is very important need. Accordingly the clogged filter needs to be cleaned frequently resulting in many visits of the service technician, more fatigue and cost. More over the clogged filter is very difficult to replace.
[0005] Hence there is a need to provide a self cleaning filter to prevent the dust from being collected inside the filter surface. Hence there is a need to provide a filter which requires less maintenance and the service cost required for cleaning the filter is less.
C) OBJECTS OF THE INVENTION
[0006] The primary object of the present invention is to provide a self cleaning filter with cleaning mechanism to continuously clean the inner surface of the filtering element in the fuel dispensers easily efficiently and cheaply.

[0007] Another object of the present invention is to provide a self cleaning filter for fuel dispensers to clean the clogged filter without requiring any regular inspection form the service technician.
[0008] Yet another object of the present invention is to provide a self cleaning filter for fuel a dispenser which is suitable for fluids with various densities.
[0009] Yet another object of the present invention is to provide a self cleaning filter for fuel dispenser to reduce the number of cleaning cycle required for cleaning the filter and to reduce the operational cost required for cleaning the filter.
[0010] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0011] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0012] The various embodiments of the present invention provide a self cleaning filter assembly for liquid or fuel dispensers. According to one embodiment of the present invention, a self cleaning filter assembly has a fitter casing provided with a filter unit. The filter unit is arranged inside the filter casing. A filter mesh element is arranged in the filter chamber provided inside the filter unit to filter the dust particles in the fluid. A

check valve assembly is coupled to the filter unit and arranged inside the filter unit. The check valve is lifted due to fuel pressure to permit the flow of the fuel thorough the filter unit. Pluralities of balls with bristles are arranged freely inside the filter unit. The pluralities of the balls with bristles get tumbled inside the filter chamber in the filter unit due to the flow of the fluid inside the filter chamber of the filter unit to rub the filter mesh element to clean the surface of the filter element. The balls with bristles settle down at the bottom, when the fuel flow is stopped. A dust collector is provided at the bottom of the filter housing to receive and hold the dust particles removed from the surface of the filter mesh element.
[0013] The self cleaning filter assembly comprises small balls with bristles around its periphery. The bristled balls are enclosed inside the filter assembly to clean the inner surface of the filtering assembly. It is free to tumble inside the filter assembly by means of fluid pressure generated by the pump. Due to tumbling action, the bristles continuously rub to the inner surface of the filtering chamber hence it will not allow the dirt to get accumulated on the filtering element. The self cleaning filter can be used in petrol pump and all kind of fuel or liquid dispenser. It reduces the number of cleaning cycles required for cleaning the filter thereby reducing the operational cost of filter cleaning.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The other objects, features and advantages will occur to those skilled in the art
from the following description of the preferred embodiment and the accompanying drawings in which:

[0015] FIG. 1 shows a perspective view of the self cleaning filter assembly according to one embodiment of the present invention.
[0016] FIG. 2 shows a cross sectional view of the self cleaning filter according to one embodiment of the present invention.
[0017] FIG. 3 shows an exploded perspective view of the self cleaning filter assembly according to one embodiment of the present invention.
[0018] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0019] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0020] The various embodiments of the present invention provide a self cleaning filter assembly for liquid or fuel dispensers. According to one embodiment of the present invention, a self cleaning filter assembly has a filter casing provided with a filter unit.

The filter unit is arranged inside the filter casing. A filter mesh element is arranged in the filter chamber provided inside the filter unit to filter the dust particles in the fluid. A check valve assembly is coupled to the filter unit and arranged inside the filter unit. The check valve is lifted due to fuel pressure to permit the flow of the fuel thorough the filter unit.
[0021] Pluralities of balls with bristles are arranged freely inside the filter unit. The pluralities of the balls with bristles get tumbled inside the filter chamber in the filter unit due to the flow of the fluid inside the filter chamber of the filter unit to rub the filter mesh element to clean the surface of the filter element. The balls with bristles are tumbled and rotated continuously inside the filter chamber due to the fuel flow pressure inside the filter chamber to rub the filter mesh element continuously. The balls with bristles rub the surface of the filter mesh element to clean the surface continuously and to prevent the accumulation of the dust on the surface of the filter mesh element to maintain the constant flow of the fuel at the desired rate. The balls with bristles settle down at the bottom, when the fuel flow is stopped. The balls with bristles are rotated and tumbled, only when the fluid flow is maintained through the filter chamber.
[0022] A dust collector is provided at the bottom of the filter housing to receive and hold the dust particles removed from the surface of the filter mesh element. A top cover is fastened to the filter casing using fasteners like bolt and nut arrangement etc.
[0023] According to one embodiment of the present invention, a self cleaning filter assembly includes pluralities of small balls with bristles arranged inside the filter unit

freely. The bristled balls are enclosed inside the filter assembly to clean the inner surface of the filtering assembly. The bristled balls are free to tumble inside the filter assembly, due to the fluid pressure generated by the pump. Due to tumbling action, the bristles continuously rub the inner surface of the filtering chamber. The self cleaning filter can be used in petrol pump and all kind of fuel or liquid dispenser. It reduces the number of cycle times required for cleaning the filter and reduces the operational cost of filter cleaning.
[0024] The fuel dispensers or pumps are used for dispensing fuel into vehicle. The self cleaning filter is fitted between pumping unit and inlet of the fuel dispenser in case of suction system or between submersible turbine pump and metering unit in case of a remote system. The self cleaning filter is used in petrol pump and all kind of fuel or liquid dispenser. According to one embodiment of the present invention, the self cleaning filter includes a filter assembly. The check valve assembly and balls with bristles are placed inside the filter assembly. The bristle balls are less in weight, portable and easy to replace, since its size is in microns. The filter assembly with bristled balls is enclosed in the filter casing. Accordingly, when the pump starts, due to the vacuum pressure created by the pump, the fuel is sucked from the underground fuel tank. Simultaneously, due to fuel pressure the check valve is lifted up and fuel enters inside chamber of filter assembly. The fuel flows inward to outward direction, as shown by the arrow direction. Due .to flow of fluid, the bristled balls get tumbled in the inside chamber of the filter assembly and the ball bristles starts rubbing the inner filter mesh. As a result the bristled ball continuously cleans the surface of filtering element and hence eliminates the dirt

from getting accumulated on the filter element surface. Once the delivery stops, the dirt gets settled in the dust collector or drain plug provided at the bottom of the Filter.
[0025] After delivery completion, when the pump stops, the balls get settled down. Again with next delivery the pressure rises and balls starts tumbling inside the filter chamber. Because of this repeated operation, effective performance of filter self cleaning is achieved. The cycle time of filter cleaning will increase and the filter clogging problem gets reduced. The self cleaning filter is suitable for low and high flow rate pumps/dispensers.
[0026] FIG. 1 shows a perspective view of the self cleaning filter assembly according to embodiment of the present invention. As shown in FIG. 1. the self cleaning filter includes a filter assembly 103 which is enclosed in the filter casing 102 and closed using top cover 101. The check valve assembly 106 and balls with bristles 104 are enclosed inside the filter assembly 103. The size of the bristled balls 104 is in microns. Accordingly, when the pump starts, due to the vacuum pressure created by the pump, the fuel is sucked from the underground fuel tank. Simultaneously, due to fuel pressure the check valves 106 is lifted and fuel enters inside the chamber of filter assembly 103. Due to flow of fluid, the bristled balls 104 get tumbled in the inside chamber of the filter assembly 103 and the ball bristles 104 starts rubbing the filter mesh element. As a result the bristled ball 104 continuously cleans the surface of filtering element and hence eliminates the dirt from getting accumulated on the filter element surface. Once the delivery stops, the dirt gets settled in the dust collector or drain plug 105 provided at the bottom of the filter. After delivery completion, when the pump stops, the balls get settled down. Again with next

delivery the pressure rises and balls starts tumbling inside the filter chamber. Because of this repeated operation, effective performance of filter self cleaning is achieved. The cycle time of filter cleaning will increase and the filter clogging problem gets reduced. The self cleaning filter is suitable for low and high flow rate pumps/dispensers.
[0027] FIG. 2 shows a cross sectional view of the self cleaning filter according to one embodiment of the present invention. As shown in FIG. 2, the balls with bristles 104 around its periphery are enclosed inside the filter assembly. The bristled balls 104 are free to tumble inside the filter assembly 103. When pump starts, the fuel is sucked from the underground fuel tank due to vacuum pressure. Due to fuel pressure the check valve 106 gets lifted and fuel enters inside chamber of filter element and flows inward to outward direction, in the direction of arrow. Due to flow of fluid the bristled balls 104 gets tumbled in the inside the filter assembly 103 and the ball bristles 104 starts rubbing the inner surface. As a result, it continuously cleans the inner surface of filter. When the pump stops, the dirt gets settled in the dust collector 105 provided at the bottom of the filter.
[0028] FIG. 3 shows an exploded view of the self cleaning filter according to embodiment of the present invention. As shown in FIG. 3, the filter casing 2 includes inlet 301 and outlet 302 opening. It includes check valve assembly 106 at the bottom of the casing. The check valve assembly 106 and balls with bristles 104 are enclosed in the filter assembly 3. The entire filter assembly is enclosed in a casing 102 and closed using a top cover 101. When the pump starts, due to the vacuum pressure created by the pump, the fuel is sucked from the underground fuel tank. Due to fuel pressure the check valve

106 gets lifted and fuel enters inside chamber of filter assembly 103 and flows inward through inlet valve 301. Due to the flow of fluid, the bristled balls 104 get tumbled in the inside chamber of the filter assembly 103 and the ball bristles 104 starts rubbing the filter mesh element. As a result the bristled ball 104 continuously cleans the surface of filtering element and hence eliminates the dirt from getting accumulated on the filter element surface. The filtered fuel is output through the out let opening 302 in the casing 302. Once the delivery stops, the dirt gets settled in the dust collector or drain plug 105 provided at the bottom of the filter. The drain plug can be opened to remove the dust particles. After delivery completion, when the pump stops, the balls get settled down. Again with next delivery the pressure rises and balls starts tumbling inside the filter chamber. Because of this repeated operation, effective performance of filter self cleaning is achieved.
G) ADVANTAGES OF THE INVENTION
[0029] The various embodiments of the present invention provide a self cleaning filter assembly for liquid or fuel dispensers. It comprises of a bristled balls enclosed inside the filter casing to continuously clean the inner surface of the filtering assembly and to prevent the dust from being collected inside the filter element surface. The self cleaning filter in the present invention is suitable for all density liquid. It reduces the filter clogging time. The cycle time of filter cleaning will increase and the filter clogging problem is reduced. The self cleaning filter is suitable for low and high flow rate pumps or dispensers. The bristle balls are less in weight, portable and easy to replace. As a result the maintenance and the operational or service cost required is less.

[0030] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
[0031] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

Date: March 28, 2009. RAKESH PRABHU
Place: Bangalore. Patent Agent

CLAIMS
What is claimed is:
1. a self cleaning filter assembly comprising:
a filter casing;
a filter unit arranged inside the filter casing:
a filter chamber provided inside the filter unit;
a filter mesh element arranged in the filter chamber;
a check valve assembly coupled to the filter unit;
plurality of balls with bristles arranged freely inside the filter unit;
wherein the plurality of the balls with bristles get tumbled inside the filter
chamber in the filter unit due to the flow of the fluid inside the filter chamber of
the filter unit to rub the filter mesh element to clean the surface of the filter
element.
2. The filter assembly according to claim 1, wherein the check valve is lifted due to fuel pressure to permit the flow of the fuel thorough the filter unit.
3. The filter assembly according to claim I, wherein the balls with bristles are tumbled and rotated continuously inside the filter chamber due to the fuel flow pressure inside the filter chamber to rub the filter mesh element continuously.
4. The filter assembly according to claim 1, wherein the balls with bristles rub the surface of the filter mesh element to clean the surface continuously and to prevent the accumulation of the dust on the surface of the filter mesh element so as to maintain the constant flow of the fuel at the desired rate.

5. The filter assembly according to claim 1. further comprises a dust collector provided at the bottom of the filter housing.
6. The filter assembly according to claim 5, wherein the dust collector receives and holds the dust particles removed from the surface of the filter mesh element.
7. The filter assembly according to claim 1, wherein the balls with bristles settle down at the bottom, when the fuel flow is stopped.
8. The filter assembly according to claim 1, wherein the check valve assembly is arranged inside the filter unit.
9. The filter assembly according to claim 1 further comprises a top cover fastened to the filter casing.
10. The filter assembly according to claim 1, wherein the balls with bristles are rotated and tumbled, only when the fluid flow is maintained through the filter chamber.

Rakesh Prabhu,
Patent Agent, ALMT Legal,
No.2, Lavelle Road, Bangalore-560 001, INDIA
To,
The Controller of Patents,
The Patent office,
Mumbai
Dated this 28TH of March, 2009