Description:TECHNICAL FIELD OF THE INVENTION
The system of the present invention relates to fuel tanks. More particularly, the present invention relates to providing a system for cleaning an underground storage tank and reducing contaminants in the fuel. This may help in keeping the underground fuel tank clean which would promote oil companies of supply initiative station also clean fuel to the vehicle engines will promote a healthy combustion system which would lower pollution level through vehicular emission to the environment and will benefit the vehicular owner lower maintenance cost.

BACKGROUND OF THE INVENTION
One of the most difficult problems is cleaning the underground fuel tanks, debris or other types of contamination is detrimental to the overall operation and continued life of the engine, and creates difficulty in maintaining the smooth running of the engine during the use. In an effort to rectify this problem, systems for cleaning fuel tanks have included the removal of water and sludge from the fuel through the use of various means. For example, a concentric suction--discharge arrangement has been used in fuel cleaning operations for many years; likewise, gravity separators and cartridge filters are used in many different applications in the industries. However, the use of a cartridge filter as a direct filter means of cleaning of diesel is a very expensive proposition, in view of the fact that the major sludge found in diesel or the like fuel begins to clog up a cartridge filter very quickly, and therefore the filter must be
changed quite often.US20040020271 A1 discloses a fueling environment includes a contaminant collection chamber positioned in an underground fuel storage tank. Sumps in the fuel dispensers and low point sumps in the piping network drain captured fuel and contaminants to the contaminant chamber by methods such as gravity. A Differential gauge monitors levels within the contaminant chamber for detecting filter clogging for filter replacement. An oil-water separator may be used to economize the use of the contaminant chamber. Further, the underground storage tank may be positioned in various locations in the fueling environment and accommodate a plurality of different types of fuels.

US20060037919 A1 discloses a fuel filtration device for the corrective and preventive maintenance of fuel and fuel containers. An inlet tube removes fuel and particles from a fuel container passing the fuel and particulates through a pre-filter that removes particles greater than ½ cm. Fuel then enters a filter press that removes the remaining contaminants less than ½ cm in size. Filtered fuel returning to the container agitates the remaining fuel and loosens particles within the underground fuel tank. The loosened particulates and fuel are removed and filtered.
WO2009055836 A1 discloses liquid hydrocarbon storage tanks are cleaned by transferring the most contaminated lower fuel layer to a filter vessel on a treatment truck where separation into a contaminants portion and a fuel portion occurs. The remnant fuel in the storage tank is cleaned by multiple passes through an external circuit on the truck. The fuel from the vessel is sometimes returned to the remnant fuel to be cleaned. The contaminants are discarded. The initial separation shortens the cleaning cycle. A flexible dip tube stiffened by a guide rod allows probing of the storage tank floor.
US5409025 A discloses an apparatus and method are disclosed for cleaning and removing particulates from underground liquid fuel storage tanks which typically have restricted access openings to the interior thereof. The apparatus is provided with a main fuel pump having an inlet and outlet, an inflow passage communicating with the pump inlet for conducting fuel to the pump from an underground liquid storage tank, and an outflow passage communicating with the pump outlet for returning fuel from the pump to the same underground tank. The inflow passage is provided with protective strainer and a jet pump for increasing and maintaining the rate and velocity of fuel flowing there through to the main pump. The method of the present invention involves the steps of first dislodging, suspending, and removing particulates from the tank by withdrawing the fuel and suspended particulates from the tank through an outer passage of a coaxial hose, filtering the particulates from the fuel, and discharging filtered fuel back into the tank through an inner passage of the coaxial hose at a high velocity to dislodge and suspend particulates in the tank into the fuel.

US5336418 A discloses a system for cleaning contaminated fuel in a fuel tank by introducing a suction line to substantially the lowermost part of the tank for suctioning off free water and heavy contaminants settled in the tank. The materials are then routed via suction to a first strainer, where free water and contaminants are trapped and retrieved. The filtrate then moves to a separation vessel, whereby the fuel is filtered through a primary filter medium, and the contaminants settle to the bottom of the vessel and are collected. The filtered fuel is then routed to a tertiary filter before being returned to the fuel tank to agitate the contaminants and facilitate this removal by the suction side of the system. This closed loop process is continued until the filtered fuel is substantially free of contaminants.

EP2390013 A3 discloses an equipment for the rapid decontamination of underground tanks used for the storage of liquid fuels, typically for storing hydrocarbons, where the equipment comprises a vehicle comprising at least one storage tank, at least one transfer pump, at least one vacuum pump, and at least one dosing pump for delivering, where required, a biocidal product and which is connected by piping to the tank to enable the transfer of the liquid from the tank to the storage tank by using the pump, that is, via the piping and connected to the tank by piping which carries on its end a sludge removal device, where the sludge removal device also comprises a special tool which has a truncated cone-shaped head with two suitably shaped slits which spray a jet at 360° covering the entire circumference of the tank surface.

The existing systems and methods for cleaning the underground fuel tanks and contaminated fuel are complex, less efficient, and expensive. The filtration stages and arrangements disclosed in the existing systems are unable to efficiently remove water, sludge, and other contaminants from the fuel.

For this reason, there is a requirement to provide an improved system for cleaning of the underground fuel storage tanks which removes water, sludge, and other contaminants from the fuel. The above described prior art system suffers from many disadvantages, which the present invention effectively eliminates.
SUMMARY OF THE INVENTION
The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

An objective of the present invention is to overcome the problems of the prior art.
An objective of the present invention to provide a fuel cleaning system utilizing a primary separator chamber and primary filter contained within a vessel.
Another objective of the present invention to provide a fuel cleaning system which is operated under vacuum suction for the first stage and pressure for the other two ( 2nd stage and 3rd stage).
Another objective of the present invention to provide a system so that there is constant agitation within the fuel tank to assure that the heavy sediments can be removed periodically from the bottom of the fuel underground tank.
Yet another objective of the present invention to provide a portable system that can be utilized to clean fuel within a tank so that the vehicular engines will perform better thereafter using the normal fuel filter which would have an enchanted life getting the maintenance cost down.
Yet another objective of the present invention to provide a cleaning system utilizing suction as a separator in the first stage in the fuel cleaning process and a primary filtration means as the principal well as the second stage use paper pleated filter and third stage of coalescer filter as in process in the cleaning system.
Yet another objective of the present invention to provide a fuel cleaning system utilizing a gravity separator which due to the flow of the fuel into the separator creates a central low-pressure zone and a peripheral high-pressure zone to facilitate the movement of the fuel at the upper level of the separator into a filtration zone.
In the present invention, there is provided a first separator stage a chamber including an inlet means for allowing contaminated fluid to be suctioned to the chamber for circulating the fuel so the centripetal force within the tank forces and heavier solids out against the wall of the chamber for falling to the bottom of the chamber during the process. Further, there is included an initial floor baffle plate wherein the solids which have gathered along the wall of the chamber move to the very bottom of the chamber where they are discharged through a discharge port from the main body of the fuel. As the fuel is circulated, there is included a second stage located after the first stage of the cleaning process both these filter casing have above the inlet line having a centrally located orifice, wherein the fuel moves upward through initial filtering means such as felt and paper pleated arrangement or the like where the contaminant which was not separated out of the fuel in the separator portion is filtered through the first filter means. The fuel then flows to a second, secondary filter means, which filters out to size up to 10 microns. The fuel then flows to a second segment which filters out up to size 10 microns. Then the fuel, being relatively clean is passed through a coalescer filter in which any remaining water droplets are separated, and clean and dry fuel is returned into the return line to the bottom of the tank. This is in effect a closed-loop system with the fuel within a tank being circulated throughout the separator and filter means a number of times until the entire body of fuel within a tank has been cleaned.
In a first aspect of the invention, the invention provides a system for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising at least one underground fuel tank adapted to store the fuel, at least one suction line with a suction mouth adapted to suck the fuel from the at least one underground tank to a stage 1 filtration chamber comprising at least one gravity separator adapted to settle the contaminants or water contained within the fuel at the bottom of the gravity separator, a primary filter contained within the gravity separator of the stage 1 filtration chamber with a filter means 1 adapted to filter the remainder fuel from the gravity separator of the stage 1 filtration chamber, a non-return valve adapted to move the fuel from stage 1 filtration chamber through a gear pump to a stage 2 filtration chamber, a secondary filter contained within a gravity separator of the stage 2 filtration chamber with a filter means 2 adapted to filter the remainder fuel from the gravity separator of the stage 2 filtration chamber, a discharge line adapted to move the fuel from the stage 2 filtration chamber to the stage 3 filtration chamber, a tertiary filter contained within a gravity separator of the stage 3 filtration chamber with a filter means 3 adapted to filter the remainder fuel from the gravity separator of the stage 3 filtration chamber wherein the fuel from the stage 3 filtration chamber is further pumped to an isolation valve and a quick fix coupling to a return line adapted to pump the fuel from the stage 3 filtration chamber to the underground fuel tank and wherein the fuel is passed through the underground fuel tank for recurring circulation through stage 1 filtration chamber to stage 3 filtration chamber till the fuel is filtered to 10 micron filtration.
In an implementation of the aspect as described above, the stage 1 filtration chamber and the stage 2 filtration chamber are sealed by a top lid with a fuel compatible O ring adapted to be used as a gasket to seal the top lid to the stage 1 filtration chamber.
In an implementation of the aspect as described above, the top lid of the stage 1 filtration chamber and stage 2 filtration chamber is further equipped with a ball valve adapted to release any vapors lock that occurred in the stage 1 filtration chamber.

In an implementation of the aspect as described above, the filter means 1 of the primary filter is a polyester felt cloth wrap filter, the filter means 2 of the secondary filter is a paper pleated filter in a casing of the filter means 2 and the filter means 3 of the tertiary filter is a coalescer filter.

In an implementation of the aspect as described above, the stage 1 filtration chamber and stage 2 filtration chamber comprise a fixture to support the polyester felt cloth wrap filter and the paper pleated filter respectively.

In an another aspect of the present invention, the invention provides a process for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising transferring fuel from at least one underground fuel tank through at least one suction line with a suction mouth to a stage 1 filtration chamber, settling the contaminants or water contained within the fuel at the bottom of a gravity separator of the stage 1 filtration chamber, filtering the remainder fuel from the gravity separator of the stage 1 filtration chamber by passing through a primary filter contained within the gravity separator of the stage 1 filtration chamber, transferring the fuel from stage 1 filtration chamber to a stage 2 filtration chamber through a gear pump, filtering the remainder fuel from a gravity separator of the stage 2 filtration chamber by passing through a secondary filter contained in the gravity separator of the stage 2 filtration chamber, transferring the fuel from stage 2 filtration chamber to the stage 3 filtration chamber through a discharge line, filtering the remainder fuel from a gravity separator of the stage 3 filtration chamber by passing through a tertiary filter contained in the gravity separator of the stage 3 filtration chamber wherein pumping the fuel from the stage 3 filtration chamber to an isolation valve and a quick fix coupling to a return line for pumping the fuel from the stage 3 filtration chamber to the underground fuel tank and wherein the fuel is passed through the underground fuel tank for recurring circulation through stage 1 filtration chamber to stage 3 filtration chamber till the fuel is filtered to 10 micron filtration.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 Illustrates a schematic view of the system for underground fuel storage tank cleaning, according to one of the embodiments of the present invention.

Figure 2 Illustrates an elevation, side view, plan view of the first stage filtration of the system, according to one of the embodiments of the present invention.

Figure 3 Illustrates an elevation, side view, plan view of the second stage filtration of the system, according to one of the embodiments of the present invention.

Figure 4 Illustrates an elevation, side view, plan view of the first stage filtration of the system, according to one of the embodiments of the present invention.

Figure 5 Illustrates the flow process of the underground fuel storage tank cleaning, according to one of the embodiments of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may not have been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to "a component surface" includes a reference to one or more of such surfaces.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments belong. Further, the meaning of terms or words used in the specification and the claims should not be limited to the literal or commonly employed sense, but should be construed in accordance with the spirit of the disclosure to most properly describe the present disclosure.

The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

The system of the present invention solves the shortcomings in the art simply and straightforwardly. The fuel cleaning system of the present invention includes removal of water and sludge which is accomplished using a felt separator with a vacuumed extracting means in series with paper cartridge filter. The filter removes particles larger than 10 microns, however, may be used in filter cartridges which can clean fuel up to lower than 10 microns, if required, plus any water that was not removed in the gravity separator. Clean fuel from the filter is discharged at the bottom of the fuel tank at high velocity through a small opening. This agitates the water and sludge. The suction side of the system is located approximately one inch above the high-velocity discharge where it picks up the water and sludge for removal by the separator and filter sections. Fuel in the tank is continuously circulated through the system. During the process, water and sludge are drained from the separator and filter as accumulated. The system is powered by an explosion-proof electric motor driving a pump that handles approximately 5 gallons per minute but may be utilized with a unit that can handle 60 to 80 litres per minute. There are two hoses from the separated filter (1 supply hose and 1 return hose), each being approximately 20 feet long.

The first stage of the system is the fuel cleaning stage utilizing a gravity separator. This makes it possible for the heavy sediments to settle by gravity to the bottom of the separator tank where they can be drained off while the system is in operation. The contaminants which settle out in this stage are a very substantial portion of the total contaminants and may never go through the filter medium which requires cleaning. As a result, it is not necessary to shut the system down during the job to clean or change out the filter components.

In the present system, the discharge side of the separator is packed with steel wool which serves as a coalescent means, and a rough filter for the solids which did not settle out in the gravity separator. In the present system, a standard commercial filter processes and cleans the fuel which is discharged from the gravity separator filter coalescent. The particular filter used in this system. There are several different types of filter elements which are available for use in the unit with various micron rating and water removal capabilities.

In the present system, the pumping unit is independent of the fuel cleaning facilities. The complete unit consists of two identical fuel cleaning units (gravity separator plus cartridge filter), and necessary hoses. The present system of the separator and the filter operates on the pressure rather than the vacuum. In the system, sediments in the tank are purposely agitated by the suction/discharge assembly so that the heavy sediments can be removed periodically. This way the installed fuel filter equipment when used keeps the vehicular engine healthy hence is not overloaded and shut down by heavy contaminants carried by contaminated fuel.
In an embodiment of the present invention, a system for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising at least one underground fuel tank (30) adapted to store the fuel, at least one suction line (7) with a suction mouth (1) adapted to suck the fuel from the at least one underground tank (30) to a stage 1 filtration chamber (3) comprising at least one gravity separator (32) adapted to settle the contaminants or water contained within the fuel at the bottom of the gravity separator, a primary filter (4) contained within the gravity separator (32) of the stage 1 filtration chamber (3) with a filter means 1 adapted to filter the remainder fuel from the gravity separator (32) of the stage 1 filtration chamber (3), a non-return valve (13) adapted to move the fuel from stage 1 filtration chamber (3) through a gear pump (14) to a stage 2 filtration chamber (19), a secondary filter (36) contained within a gravity separator (33) of the stage 2 filtration chamber (19) with a filter means 2 adapted to filter the remainder fuel from the gravity separator (33) of the stage 2 filtration chamber (19), a discharge line (35) adapted to move the fuel from the stage 2 filtration chamber (19) to the stage 3 filtration chamber (25), a tertiary filter (28) contained within a gravity separator (34) of the stage 3 filtration chamber (25) with a filter means 3 adapted to filter the remainder fuel from the gravity separator (34) of the stage 3 filtration chamber (25) wherein the fuel from the stage 3 filtration chamber (25) is further pumped to an isolation valve (26) and a quick fix coupling (27) to a return line (29) adapted to pump the fuel from the stage 3 filtration chamber (25) to the underground fuel tank (30) and wherein the fuel is passed through the underground fuel tank (30) for recurring circulation through stage 1 filtration chamber to stage 3 filtration chamber till the fuel is filtered to 10 micron filtration.
In an additional embodiment of the present invention, it would provide a tank including a downward drive motion of fuel wherein fuel is injected at the upper portion of the chamber, fuel is required to move below the lowermost point of the baffle where the heavier contaminants within the fuel, such as solids and water, are then moved through a lower screen portion consisting of a primary felt filter and removed from the chamber through a drain line. The fuel is then moved up into the second stage portion beyond the first chamber where it meets with the secondary filter medium such as a paper pleated filter or the like where the secondary components are filtered out, and then are discharged into a secondary filtration means where the remaining components (again up to 10 or less micron size) is filtered out and returned into the tank via inlet line to third stage coalescer filter returned to the fuel underground tank.
Additionally, the preferred embodiment utilizing the cylindrical chambered vessel could be utilized in conjunction in a fuel line between a fuel tank and the tank return line. Whereby all fuel moving from the fuel tank to the cleaning system could pass through the separator and primary filter /secondary filters means contained within the separator tank for assuring cleaner fuel within the line than would be present without such filtration unit therein. Utilized in this mode, the separator will perform satisfactorily operating under pressure or a vacuum.
In an another embodiment of the present invention, the invention provides a process for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising transferring fuel from at least one underground fuel tank (30) through at least one suction line (7) with a suction mouth (1) to a stage 1 filtration chamber (3), settling the contaminants or water contained within the fuel at the bottom of a gravity separator (32) of the stage 1 filtration chamber (3), filtering the remainder fuel from the gravity separator (32) of the stage 1 filtration chamber (3) by passing through a primary filter (4) contained within the gravity separator (32) of the stage 1 filtration chamber (3), transferring the fuel from stage 1 filtration chamber (3) to a stage 2 filtration chamber (19) through a gear pump (14), filtering the remainder fuel from a gravity separator (33) of the stage 2 filtration chamber (19) by passing through a secondary filter (36) contained in the gravity separator (33) of the stage 2 filtration chamber (19), transferring the fuel from stage 2 filtration chamber (19) to the stage 3 filtration chamber (25) through a discharge line (35), filtering the remainder fuel from a gravity separator (34) of the stage 3 filtration chamber (25) by passing through a tertiary filter (28) contained in the gravity separator (34) of the stage 3 filtration chamber (25) wherein pumping the fuel from the stage 3 filtration chamber (25) to an isolation valve (26) and a quick fix coupling (27) to a return line (29) for pumping the fuel from the stage 3 filtration chamber (25) to the underground fuel tank (30) and wherein the fuel is passed through the underground fuel tank (30) for recurring circulation through stage 1 filtration chamber to stage 3 filtration chamber till the fuel is filtered to 10 micron filtration.

The system of the present invention is illustrated in the schematic illustration in figure 1 which shows each component of the system disclosed in the present invention. What is provided in the illustration of figure 1 is an underground fuel tank (30) of the type contained upon a cylindrical vessel which would in most instances contains a fuel such as gasoline, kerosene, or diesel fuel, of quantities up to thousands of Kilo liters at a time. What is provided initially as seen in the cross-section of the tank (30) is a suction line (7) having there within a return line/discharge hose (29). The suction line (7) will be utilized for sucking fuel from the tank portion due to the action of the pump (14) along the line with pump (14) moving the fuel contaminants along the line (7) into the next component of the system. A second component of the system as seen in figure 1, would be a gravity separator (32) of the type as will be illustrated further, wherein the fuel is allowed to move through gravity separator (32), wherein contaminants such as sludge or water contained within the fuel would move to the bottom of the gravity separator (32) and be discharged from a drain valve (6) and the remainder of the fuel would move through a primary filter (4) contained within the gravity separator stage 1 filtration chamber (3), out of stage 1 through a fuel will move from stage 1 filter to gear pump (14) through a non-return valve (13) into a gear pump (14). The suction vacuum generated by the gear pump (14) would be indicated on the vacuum gauge (11) whenever necessary opening the isolation valve (9) located at the inlet of the vacuum gauge the vacuum pressure can be viewed. The gear pump (14) is equipped with an external and an internal bypass valve (10) which will regulate the pressure built up generated by the gear pump (14). The pressure developed by the gear pump will be indicated on the pressure gauge (12) located on the outlet of the gear pump (14). The pressure can be viewed by opening the isolation valve (15) on the discharge line of the pump. The discharge line of the gear pump is further given to a three-way valve (16). The three-way valve (16) has two branchings, branching 1 of the discharge line move to stage 2 filtration (19). The other end of the branching is provided with a drain plug (17). Drain plug (17) is provided for taking samples of filtration stage 1 for testing. Through the discharge line of the branching, the fuel from stage 1 of the cleaning stage is pumped to stage 2 of the filtration system. In the filter casing (21) the fuel is passed through a paper pleated filter of ten-micron grain purity. The fuel is moved through a gravity separator (33) of the stage two filtration process. The fuel and water are separated at this stage through a gravity separator (33). Water accumulated at the bottom of the gravity separator is removed from the system using the drain valve (18). Filtered fuel is moved through the paper pleated filter (21) to the discharge of the filtration stage 2. The fuel can be checked after drain water through (18) for testing. An isolation valve (22) is provided to control the flow to filtration stage 3 from filtration stage 2. From filtration stage 2 a Discharge line moves the fuel to the filter stage 3 filtration chamber (25). The stage gravity separator (34) separate any water droplets remaining in fuel are passed over from filtration stage 1 to 2 of fuel cleaning is drained. A drain valve is provided at the bottom of each filtration chamber (6, 18, and 23) will facilitate to drain water from fuel separation. Stage 3 of the filtration system will trap fine droplets of water to the gravity separator and further enabling to drain this from the drain valve (23). The cleaned fuel is passed through stage 1, stage 2, stage 3 of the filtration is further pumped to the isolation valve (26) and quick fix coupling (27) to the discharge hose/return line (29). The operation of drawing contaminated fuel from the underground fuel tank (30) and filtering this through the filtration stages 1, 2, 3 is again fed to the underground tank (30). This circulation process is several times till this ensures the fuel in the underground tank is clean and filtered to 10-micron filtration.

Figure 2 Illustrates an elevation, side view, plan view of the first stage filtration of the system. It discloses component -1: Visigauge (provided to view the product flow thru the chamber and the fuel transparency), component 2: Bracket to anchor the filter casing to assly frame body, component 3: Filter drain, component 4: Filter outlet (N2) and component 5 – Filter inlet (N1).

In an embodiment of the invention, in the first stage filtration: The filter chamber is equipped with a sight glass window component, which gives a clear view of the product suctioned in from the underground fuel tank, the coloration of the product, and view of the water content in the fuel. The product is suctioned into this filtration stage through an inlet nozzle connected to a metal braided clear transparent hose which is lowered to the tank bottom. The first filtration chamber (3) is sealed by the top lid with a fuel compatible O ring used as a gasket to seal the lid with the filter chamber; the lid is also equipped with a ball valve to release any vapors lock occurred in the filtration chamber (3). The filter chamber (3) is provided with a fixture to hold the polyester felt cloth wrap filter. The fuel is passed through to the outlet of the filter, water being heavier than fuel settles down at filter chamber (3) bottom from where it can be drained out using the drain provided N3 on the filter chamber.

Figure 3 illustrates an elevation, side view, plan view of the second stage filtration of the system. It discloses component 1: Inlet to filter chamber, component 2: Outlet to filter chamber, component 3: Air release port, component 4: Filter drain and component -5: Bracket for anchoring filter case.

Figure 4 Illustrates an elevation, side view, plan view of the first stage filtration of the system. It discloses component -1: Inlet to filter casing, component -2: outlet to filter casing, Component -3: air release, Component -4: Filter drain port and component -5: Bracket for anchoring filter case.

In an embodiment of the invention, in the second stage filtration: The filter chamber (19) is feed with fuel through a gear pump (14) mounted prior to the 2nd stage filtration chamber (19). This chamber is equipped with a fixture to support the paper pleated filter. The lid of the chamber (19) is sealed used a fuel resistance O ring, this lid is also equipped with a ball valve on N3 to release vapor created in the chamber the fuel is passed thru the paper pleated filter used in stage two of the filtration system and exit the chamber through the N2 filter outlet. The water in the fuel settles down as this is heavier than fuel and can be drained through the N4 outlet provided for water draining.

In an embodiment of the invention, in the third stage filtration: The filter chamber (25) provided in the third stage is to separate remnant water from the fuel. The fuel is passed to this stage through the inlet N1 from the stage 2 filtration outlet. The fuel is passed thru a coalescer filter element. Water is not allowed to pass through the next stage and the same is repelled by the coalescer filter element. Collected water at the bottom can be seen through a sight glass N6 which can be drained thru N5. Only fuel is passed on through the underground tank for recurring circulation. Once the fuel is appeared to be cleaned the sample can be drained from the underground tank bottom and sample tested for a clear specification.

Figure 5 illustrates the flow process of the underground fuel storage tank cleaning. It shows all the three filtration stages where the contaminated fluid which is sucked from the underground fuel storage tank (30) is passed through the stage 1 filtration chamber (3) to the stage 3 filtration chamber via a stage 2 filtration chamber (19) and finally from the filtered fuel from stage 3 filtration chamber (25) is further pumped to an isolation valve (26) and a quick fix coupling (27) to a return line (29) adapted to pump the fuel from the stage 3 filtration chamber (25) to the underground fuel tank (30) for recurring circulation through the all three filtration stages.
Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
Those skilled in the art will recognize other use cases, improvements, and modification to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.

Claims:WE CLAIM:

1. A system for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising:
at least one underground fuel tank (30) adapted to store the fuel;
at least one suction line (7) with a suction mouth (1) adapted to suck the fuel from the at least one underground tank (30) to a stage 1 filtration chamber (3) comprising at least one gravity separator (32) adapted to settle the contaminants or water contained within the fuel at the bottom of the gravity separator;
a primary filter (4) contained within the gravity separator (32) of the stage 1 filtration chamber (3) with a filter means 1 adapted to filter the remaining fuel from the gravity separator (32) of the stage 1 filtration chamber (3);
a non-return valve (13) adapted to move the fuel from stage 1 filtration chamber (3) through a gear pump (14) to a stage 2 filtration chamber (19);
a secondary filter (36) contained within a gravity separator (33) of the stage 2 filtration chamber (19) with a filter means 2 adapted to filter the remaining fuel from the gravity separator (33) of the stage 2 filtration chamber (19);
a discharge line (35) adapted to move the fuel from the stage 2 filtration chamber (19) to the stage 3 filtration chamber (25);
a tertiary filter (28) contained within a gravity separator (34) of the stage 3 filtration chamber (25) with a filter means 3 adapted to filter the remaining fuel from the gravity separator (34) of the stage 3 filtration chamber (25);
wherein the fuel from the stage 3 filtration chamber (25) is further pumped to an isolation valve (26) and a quick fix coupling (27) to a return line (29) adapted to pump the fuel from the stage 3 filtration chamber (25) to the underground fuel tank (30); and
wherein the fuel is passed through the underground fuel tank (30) for recurring circulation through stage 1 filtration chamber (3) to stage 3 filtration chamber (25) till the fuel is filtered to 10-micron filtration.

2. The system as claimed in claim 1, wherein the stage 1 filtration chamber (3) and the stage 2 filtration chamber (19) are sealed by a top lid with a fuel compatible O ring adapted to be used as a gasket to seal the top lid to the stage 1 filtration chamber (3).

3. The system as claimed in claim 2, wherein the top lid of the stage 1 filtration chamber and stage 2 filtration chamber (19) is further equipped with a ball valve adapted to release any vapors lock occurred in the stage 1 filtration chamber (3).

4. The system as claimed in claim 1, wherein the filter means 1 of the primary filter (4) is a polyester felt cloth wrap filter.

5. The system as claimed in claim 1, wherein the filter means 2 of the secondary filter is a paper pleated filter in a casing (21) of the filter means 2.

6. The system as claimed in claim 1, wherein the filter means 3 of the tertiary filter (28) is a coalescer filter.

7. The system as claimed in claim 1, wherein the stage 1 filtration chamber (3) and stage 2 filtration chamber (19) comprises a fixture to support the polyester felt cloth wrap filter and the paper pleated filter respectively.

8. The system as claimed in claim 1, wherein the stage 1 filtration chamber is equipped with a sight glass window component adapted to give a clear view of the interior of the stage 1 filtration chamber (3).

9. The system as claimed in claim 1, wherein the system is powered by an explosion-proof electric motor driving the gear pump (14) which handles approximately 5 gallons per minute.

10. The system as claimed in claim 1, wherein the gear pump (14) is equipped with an external and an internal bypass valve (10) adapted to regulate pressure built up generated by the gear pump (14)

11. The system as claimed in claim 10, wherein the pressure built up generated by the gear pump will be indicated on the pressure gauge (12) located on the outlet of the gear pump 14.

12. The system as claimed in claim 1, wherein the gear pump (14) comprises a discharge line connected to a three-way valve 16 having at least two branching adapted to connect one end of the branching to the stage 1 filtration chamber (3) to stage 2 filtration chamber (19) and another end of the branching to a drain plug (17).

13. The system as claimed in claim 12, wherein the drain plug 17 is adapted to take samples of stage 1 filtration chamber (3) for testing.

14. The system as claimed in claim 1, wherein the system comprises an isolation valve (22) adapted to control the flow to the stage 3 filtration chamber (25) from the stage 2 filtration chamber (25).

15. The system as claimed in claim 1, wherein the stage 1 filtration chamber (3) comprises a drain valve (6) adapted to remove water and the contaminants accumulated at the bottom of the gravity separator (32) of the stage 1 filtration chamber (3).

16. The system as claimed in claim 1, wherein the stage 2 filtration chamber (19) comprises a drain valve (18) adapted to remove water accumulated at the bottom of the gravity separator (33) of the stage 2 filtration chamber (19).

17. The system as claimed in claim 1, wherein the stage 3 filtration chamber (19) comprises a drain valve (23) adapted to remove water accumulated at the bottom of the gravity separator (34) of the stage 3 filtration chamber (25).

18. The system as claimed in claim 1, wherein the suction line (7) and the return line (29) are steel braided transparent hoses.

19. A process for underground fuel storage tank cleaning and reducing contaminants in fuel, said system comprising:
transferring fuel from at least one underground fuel tank (30) through at least one suction line (7) with a suction mouth (1) to a stage 1 filtration chamber (3);
settling the contaminants or water contained within the fuel at the bottom of a gravity separator (32) of the stage 1 filtration chamber (3);
filtering the remaining fuel from the gravity separator (32) of the stage 1 filtration chamber (3) by passing through a primary filter (4) contained within the gravity separator (32) of the stage 1 filtration chamber (3);
transferring the fuel from stage 1 filtration chamber (3) to a stage 2 filtration chamber (19) through a gear pump (14);
filtering the remaining fuel from a gravity separator (33) of the stage 2 filtration chamber (19) by passing through a secondary filter (36) contained in the gravity separator (33) of the stage 2 filtration chamber (19);
transferring the fuel from stage 2 filtration chamber (19) to the stage 3 filtration chamber (25) through a discharge line (35);
filtering the remaining fuel from a gravity separator (34) of the stage 3 filtration chamber (25) by passing through a tertiary filter (28) contained in the gravity separator (34) of the stage 3 filtration chamber (25);
wherein pumping the fuel from the stage 3 filtration chamber (25) to an isolation valve (26) and a quick fix coupling (27) to a return line (29) for pumping the fuel from the stage 3 filtration chamber (25) to the underground fuel tank (30); and
wherein the fuel is passed through the underground fuel tank (30) for recurring circulation through stage 1 filtration chamber (3) to stage 3 filtration chamber (25) till the fuel is filtered to 10-micron filtration.