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 WITH PROPELLER
MECHANISM


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 systems and particularly to self cleaning filter assembly for liquid or fuel dispensers. The invention more particularly relates to a cleaning mechanism in self cleaning filter assembly.
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 the accurate amount of fuel dispensed. The measurement of fuel is conveyed by an electronic or mechanical console. One of the major requirements 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 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 the fuel is sucked from the underground storage tank through pipe lines due to the vacuum pressure. 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 to 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 do not get the desired Liters Per Minute (LPM) which is very important need. Accordingly the clogged filter needs to be cleaned frequently necessitating many visits of the service technician and resulting in more fatigue and cost. More over the clogged filter is very difficult to replace.
[0005] In conventional filters, the frequency of the filter clogging is more and cleaning the filter twice or thrice in a month is a tedious job. More over the service technician needs to open the filter casing to clean the filter arranged inside filter chamber and to close the filter casing again. This process is time consuming. Due to this, the pump is shut down for around half an hour thereby affecting the sales of the product.
[0006] Hence there is a need to provide a self cleaning filter to prevent the dust from being collected inside the filter surface. Also 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
[0007] The primary object of the present invention is to provide a self cleaning filter with a cleaning mechanism to continuously clean the inner surface of the filtering element in the liquid dispensers easily and efficiently.
[0008] Another object of the present invention is to provide a self cleaning filter with propeller mechanism to clean the clogged filter frequently without requiring any regular inspection from the service technician.
[0009] Yet another object of the present invention is to provide a self cleaning filter with a cleaning mechanism which is suitable for filtering all density fluids in liquid dispenser.
[0010] Yet another object of the present invention is to provide a self cleaning filter with a cleaning mechanism to reduce the downtime or outage duration required for cleaning the filter and to reduce the operational cost required for cleaning the filter.
[0011] 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
[0012] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

[0013] 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 inside which a filter unit is arranged. A filter mesh element is arranged inside the filter chamber provided inside the filter unit. An impeller check valve assembly is coupled to the filter unit. The impeller check valve assembly is lifted up due to the pressure of the fluid to permit the passage of the fluid through the filter chamber. A cover is fastened to the filter casing at the top portion.
[0014] A propeller assembly is arranged inside the filter element. The propeller assembly is coupled to the top cover of the casing. The propeller assembly includes plurality of blades with a curved profile. The blades in the propeller assembly are rotated by the vortex flow of the fluid passed through the filter chamber to agitate and remove the dust particles that are settled on the surface of the filter mesh element. The curved blade profile of the propeller assembly changes the dynamic movement of the fluid passed through the filter chamber. The blades of the propeller are rotated to drive the propeller as the vortex flow of the fluid passed through filter chamber hits the blades of the propeller assembly. The propeller is rotated to create turbulence in the fluid passed through to prevent the adherence of the dust particles carried by the fluid on the filter mesh element. The propeller blades guide the dust particles that are carried by the fluid and come in to contact with the blades to a dust collector. A dust collector is arranged at the bottom of the filter unit.

[0015] According to one embodiment of the present invention, a self cleaning filter assembly for liquid or fuel dispensers comprises of a propeller and a check valve assembly enclosed inside the filter unit. The filter unit is enclosed in a filter casing. A top cover is provided to close the filter casing. The propeller mechanism continuously cleans the inner surface of the filtering element in the liquid dispensers.
[0016] The self cleaning filter assembly includes a filtering element which is enclosed in the filter casing. The impeller check valve assembly and the propeller are placed inside the filter assembly to continuously clean the inner surface of the filtering element. Accordingly, the fuel is sucked from the underground fuel tank, when the pump is started. Due to fuel pressure, the impeller type check valve gets lifted and because of curved blade profile fuel flow dynamics gets changed. Due to the vortex flow of fuel, fuel hits the propeller vanes and drives the propeller. The dirt particles which comes along with fuel hits on the propeller blades and gets settled in the dust collector. Also propeller creates turbulence and due to this, the dirt does not get accumulated on the surface of the filter element. The cycle time of filter cleaning increases and the filter clogging problem gets reduced. This self cleaning filter is suitable for low and high flow rate pumps/dispensers.
[0017] The self cleaning filter can be used in petrol pump and all kinds of fuel or liquid dispensers. It reduces the downtime or outage duration required for cleaning the filter and reduces the operational cost of filter cleaning.

E) BRIEF DESCRIPTION OF THE DRAWINGS
[0018] 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:
[0019] FIG. 1 illustrates a perspective view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention.
[0020] FIG. 2 illustrates a cross sectional view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention.
[0021] FIG. 3 illustrates an exploded view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention.
[0022] FIG. 4 illustrates an exploded view of the propeller mechanism assembly according to one embodiment of the present invention.
[0023] 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
[0024] 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.
[0025] 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 inside which a filter unit is arranged. A filter mesh element is arranged inside the filter chamber provided inside the filter unit. An impeller check valve assembly is coupled to the filter unit. The impeller check valve assembly is lifted up due to the pressure of the fluid to permit the passage of the fluid through the filter chamber. A cover is fastened to the filter casing at the top portion.
[0026] A propeller assembly is arranged inside the filter element. The propeller assembly is coupled to the top cover of the casing. The propeller assembly includes plurality of blades with a curved profile. The blades in the propeller assembly are rotated by the vortex flow of the fluid passed through the filter chamber to agitate and remove the dust particles that are settled on the surface of the filter mesh element. The curved blade profile of the propeller assembly changes the dynamic movement of the fluid passed through the filter chamber. The blades of the propeller are rotated to drive the propeller as the vortex flow of the fluid passed through filter chamber hits the blades of the propeller assembly. The propeller is rotated to create turbulence in the fluid passed through to

prevent the adherence of the dust particles carried by the fluid on the filter mesh element. The propeller blades guide the dust particles that are carried by the fluid and come in to contact with the blades to a dust collector. A dust collector is arranged at the bottom of the filter unit.
[0027] According to one embodiment of the present invention, a self cleaning filter assembly for liquid or fuel dispensers comprises of a propeller and a check valve assembly enclosed inside the filter unit. The filter unit is enclosed in a filter casing. A top cover is provided to close the filter casing. The propeller mechanism continuously cleans the inner surface of the filtering element in the liquid dispensers.
[0028] The self cleaning filter assembly includes a filtering element which is enclosed in the filter casing. The impeller check valve assembly and propeller are placed inside the filter assembly to continuously clean the inner surface of the filtering element. Accordingly, when the pump starts the liquid or fuel is sucked from the underground tank. Due to fluid pressure, the impeller type check valve gets lifted and it hits the propeller with curved vanes.
[0029] Because of curved blade profile fuel flow dynamics gets changed. Due to the vortex flow of fuel, fuel hits the propeller vanes and drives the propeller. Hence the fluid will hit the inner surface of the filter assembly. The dust particles which comes along with fuel hits on the propeller blades and gets settled in the dust collector. Also propeller creates turbulence and due to this the dirt does not get accumulated on the surface of the filter element. The cycle time of filter cleaning will increase and the filter clogging

problem gets reduced. This self cleaning filter is suitable for low and high flow rate pumps/dispensers. The self cleaning filter can be used in petrol pump and all kind of fuel or liquid dispenser. It reduces the downtime or outage duration required for cleaning the filter and reduces the operational cost of filter cleaning.
[0030] FIG. 1 illustrates a perspective view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention. As shown in FIG. 1, the propeller 104 with the curved blades is fixed to the top cover 101. The propeller 104 and the impeller check valve assembly 106 are enclosed in filter assembly 103. The filter assembly 103 is enclosed in a filter casing 102 and closed using the top cover 101. The filter casing 102 includes a fluid inlet opening 107 at the bottom and fluid outlet opening 108 on the body of the filter casing 102. The inlet and outlet opening are provided to suck the liquid or fuel from the underground tank and to output the filtered liquid or fuel.
[0031] FIG, 2 illustrates a cross sectional view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention. It comprises of a propeller 104 with curved blades around it to clean the inner surface of the filter assembly 103. The propeller 104 with curved blades around it is enclosed inside the filter assembly 103 to clean the inner surface of the filtering assembly 103. It is free to rotate inside the filter assembly 103 by means of fluid pressure generated by the pump. The propeller 104 with curved blades on it continuously cleans the inner surface of the filtering chamber hence it will not allow the dirt to get accumulated on the filtering element. Due to fuel pressure the impeller type check valve 106 gets lifted and because of curved blade profile of impeller fuel flow dynamics gets changed. Due to the vortex flow

of fuel, fuel hits the propeller vanes and drives the propeller 104. The dirt particles which comes along with the fuel or liquid hits on the propeller blades and gets settled in the dust collector. Also propeller creates turbulence and due to this the dirt does not get accumulated on the surface of the filter element 103.
[0032] FIG. 3 illustrates an exploded view of the self cleaning filter with propeller mechanism according to one embodiment of the present invention. It shows a top cover with propeller 104, a filter assembly 103, a check valve assembly 106 and a filter casing 102. The propeller 104 is fixed with the top cover 101. The top cover 101 with propeller 104 and the check valve assembly 106 is enclosed inside the filter assembly 103. The entire assembly is enclosed inside the filter casing 102 and finally screwed with the top cover 101. The inlet opening 107 is provided on the filter casing 102 to receive the liquid or fuel from the under ground tank and the filtered liquid is output through the outlet portion 108. Once the liquid or fuel is filtered the dust particles are collected at the dust collector. The dust particles collected can be flushed out by opening the drain plug 105.
[0033] FIG. 4 illustrates an exploded view of the propeller mechanism according to one embodiment of the present invention. It shows the alignment of the top cover 101 with the propeller 104. Initially the shaft 401 is fixed to the top cover 101, and then the propeller with curved vanes 104 is inserted in to the shaft 401 through the central hole in propeller 104. Finally, the propeller 104 is screwed at the end using the provision 402 to prevent the propeller 104 from falling down. The assembly of the propeller 104 with top cover 101 is enclosed inside the filter assembly 103.

G) ADVANTAGES OF THE INVENTION
[0034] The various embodiments of the present invention provide a self cleaning filter assembly for liquid or fuel dispensers. The propeller and the check valve in the present invention is arranged to continuously clean the inner surface of the filtering element in the liquid dispensers. It reduces the downtime or outage duration required for cleaning the filter and reduces the operational cost required for cleaning the filter. It is suitable for filtering all density liquids. More over the number of cycles required for cleaning the filter is increased and hence the filter clogging problem is reduced. The self cleaning filter is suitable for low and high flow rate pumps or dispensers. As a result the maintenance and the operational or service cost required is less.
[0035] 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.

[0036] 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, 2008. 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;
an impeller check valve assembly coupled to the filter unit;
a cover fastened to the filter casing at top portion;
a propeller assembly arranged inside the filter element;
wherein the propeller assembly includes blades which are rotated by the vortex flow of the fluid passed through the filter chamber to agitate and remove the dust particles that are settled on the surface of the filter mesh element.
2. The filter assembly according to claim 1, wherein the propeller assembly includes plurality of blades with a curved profile.
3. The filter assembly according to claim 1, wherein the impeller check valve assembly is lifted up due to the pressure of the fluid to permit the passage of the fluid through the filter chamber.
4. The filter assembly according to claim 1, wherein the curved blade profile of the propeller assembly changes the dynamic movement of the fluid passed through the filter chamber.

5. The filter assembly according to claim 1, wherein the blades of the propeller are rotated to drive the propeller as the vortex flow of the fluid passed through filter chamber hits the blades of the propeller assembly.
6. The filter assembly according to claim 1, wherein the propeller is rotated to create turbulence in the fluid passed through to prevent the adherence of the dust particles carried by the fluid on the filter mesh element.
7. The filter assembly further comprises a dust collector arranged at the bottom of the filter unit.
8. The filter assembly according to claim 1, wherein the propeller blades guide the dust particles that are carried by the fluid and come in to contact with the blades to a dust collector.
9. The filter assembly according to claim 1, wherein the propeller assembly is coupled to the top cover.
10. The filter assembly according to claim 1, wherein the propeller is assembly coupled to the inner surface of the cover.
11. The filter assembly according to claim 1, wherein the propeller is coupled to the inner surface of the cover using fasteners.

12. The filter assembly according to claim 1, wherein the propeller is coupled to the inner surface of the cover using bolts and nut arrangement.
Dated this 28th of March, 2009

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