This invention relates, generally, to a system for filtering fluid and removing sludge within a storage container, and, in particular, to a sludge removal system for filtering fuel and removing sludge within a fuel storage tank.
The process of storing fuel can include a variety of problems related to retaining fuel quality. Fuel is an organic compound that reacts with air, water, and microbiological growth. It has a relatively short shelf-life and can degrade over time. Thus, when fuel is stored, contaminants often settle out from the fuel. Contaminants more dense than the fuel generally fall to the bottom of the storage tank and are often referred to collectively as sludge.
In order to maximize the usable volume of a storage tank, the fuel pick-up tube is often placed within a few inches of the bottom of the tank to ensure that the contaminants that settle upon the bottom are not drawn into the fuel pick-up tube. Having the pick-up tube near the bottom of the tank is desirable, because it allows more fuel to be withdrawn from the tank before the need to refill the tank. For example, positioning the fuel pick-up tube near the bottom of the tank can be critical for emergency power systems that run for long periods of time without having the tank refueled.
Over time, the layer of contamination on the bottom of the tank can build upward towards the pick-up tube and, consequently, contaminated fuel can be drawn from the tank. Such a result can adversely affect an engine utilizing the fuel. Adverse effects can include clogged filters, scorched injectors, complete engine failure, and other engine problems. If the layer of contamination on the bottom of the tank continues to rise, then the pick-up tube can itself become clogged, thus preventing fuel from being drawn from the tank.
Other storage tank features can contribute to fuel contamination problems. For example, most storage tanks are vented to the atmosphere to relieve pressure build-up. Yet, such venting can introduce moisture and airborne microorganisms into the tank, which eventually make their way to the bottom of the tank due to condensation and gravity. Microorganisms can grow and reproduce in this environment by living in the water while feeding on the fuel. Over time, an interface layer, which can be made up of a stringy, black mass of sediments, can form between the fuel and the water residing at the bottom of the tank. Additional sediments also form on the tank bottom from byproducts of the microorganisms' biological processes. As a result, the pH of the accumulated water decreases providing a corrosive environment. If left unchecked, layers of water and sludge can accumulate on the bottom, and eventually rise upward toward the middle of the storage tank.
Many storage tanks also include a return fuel line through which unused fuel is discharged back into the tank. The problem of suspended sludge accumulating near the bottom of the tank is compounded when fuel is dumped back into the tank through this line, because of an increased introduction of moisture and microorganisms into the tank.
Today's expensive fuel equipment has little tolerance for such dirty, contaminated fuel. For example, the orifices on injectors have become smaller to make engines more fuel-efficient. Consequently, the potential for injection wear and other complications is greater when fuel is delivered from a contaminated source. Moreover, due to the present practice of introducing chemicals to the fuel through the cracking process (to increase yield), current fuel types are more dynamic, and will precipitate particles that link together to form additional sludge. The National Fire Protection Association recognizes the potential for problems associated with contaminated fuel and has provided a standard that “fuel system design shall provide for a supply of clean fuel to the prime mover.” NFPA Standard 110, 7.9.1.2.
Various attempts have been made for reducing the previously identified problems associated with stored fuel. Drains have been introduced at the bottom of small storage tanks to evacuate sludge build-up. Larger tanks, however, are not routinely equipped with such drain plugs, because the plugs are often a source for leaks caused by the pressure of the fuel. Additionally, it is not practical to drain tanks that are full of fuel. Further, underground storage tanks cannot be accessed for drainage.
Valves can be provided, but cannot be located on the bottom of the tank, because the fuel pressure would interfere with the integrity of the seals. Valves that are located a certain distance (e.g., three inches) off the bottom of the tank will not adequately drain contaminants and sludge residing below the valve.
Water and other contaminants can be pumped off the bottom through wands that are sent to the bottom of the tank through an opening on top of the tank. Most wands, however, remain stationary and will not remove the sludge from the other end of the tank because of the angle at which the tank is positioned.
Fuel storage tanks are typically inspected and periodically cleaned to remove the build-up of contaminants. In addition, biocides or biostats can be added to the tank to destroy or inhibit the growth of microorganisms. Finally, filters can be installed and periodically changed. Because of budget constraints and differing maintenance philosophies, however, such measures are not always taken.
What is needed is a sludge removal system that will effectively remove contaminants resting on the bottom of the tank, while ensuring that the level of contaminants does not reach a level that would interfere with the pick-up tube. It is to such a device that the present invention is primarily directed.
Briefly described, in preferred form, the present invention is a sludge removal system for removing contaminants from the bottom of a fluid storage tank. The sludge removal system includes a contaminant intake for receiving contaminants within the tank and a removal member for transporting the contaminants from the contaminant intake to the outside of the tank. More specifically, the contaminant intake prevents the layer of contaminants or sludge from reaching a predetermined level within the tank, such that the predetermined level is generally the lowest level within the storage tank that a pick-up line will draw fluid. By keeping the level of contaminants from reaching the predetermined level, the pick-up line will draw desirable clean fluid, such as fuel, from the storage tank. The term fuel as used herein will be understood to mean natural or synthetic fluids that yield heat through combustion, including, but not limited to, gasoline, kerosene, diesel fuel, and heating oil.
The contaminant intake is formed to define a plurality of perforations that can receive contaminants from the storage tank. The perforations can thus be sized, shaped, and located to provide beneficial contaminant removal. Additionally, portions of the contaminant intake are in communication with the removal member via joint members, such as flexible or swivel joints. The joint members permit portions of the contaminant intake to rotatably move between a first position distal to the bottom of the tank and a second position proximate to the bottom of the tank. The contaminant intake is in the first position, or collapsed position, when the sludge removal system is introduced to, or removed from, an opening, generally at the top of the tank. As the contaminant intake nears the bottom of the tank, the contaminant intake moves to the second position, or extended position, such that the contaminant intake is generally parallel to the bottom of the tank during the removal of contaminants.
Depending upon the shape and size of the storage tank, the contaminant intake can remain stationary, include a plurality of extensions, be moved from one side of the tank to another, or be rotated in a circular pattern to maximize the covered surface area of the bottom of a tank where contaminants are removed.
In another embodiment of the present invention, the containment intake can include a plurality of joint members allowing portions of the contaminant intake to effectively extend along a contoured (or not-flat) bottom of the storage tank. Further, the contaminant intake can comprise a plurality of slideable subportions that permit telescoping retraction and extension of the contaminant intake. Moreover, the contaminant intake can comprise a number of scraping members that scrape contaminants from the bottom of the tank and direct contaminants towards the perforations of the contaminant intake. Also, each outwardly extending end of the contaminant intake can comprise a flange and a coupling end cap to maintain the pressure within the contaminant intake necessary for the removal of contaminants within the tank.
The removal member can further include a coupling member so that a suction device or other pressure differential system can be connected to the removal member to facilitate the transporting of contaminants from within the tank to outside the tank. By reversing the pressure of the suction device, air can be pumped through the removal member and the contaminant intake to clean the sludge removal system and stir up contaminants at the bottom of the tank. Accordingly, the sludge removal system removes the majority of contaminants located near the bottom of the tank and, thus, provides the pick-up line with cleaner fuel from the storage tank.
A principle object of the present invention is to provide an innovative sludge removal system designed for removing contaminants from the bottom of a fluid storage tank.
Another object of the present invention is to provide an innovative sludge removal system designed to be easily installed in current fluid storage tanks.
Still another object of the present invention is to provide a contaminant intake that is easily introduced and removed from an opening of the fluid storage tank.
It is another object of the present invention to provide a contaminant intake that removes contaminants from the bottom of the fluid storage tank and ensures that the top level of the contaminants does not reach a predetermined level generally designated as the lowest level that a pick-up line draws fluid from the fluid storage tank.
Yet another object of the present invention is to provide an effective sludge removal system that adequately removes contaminants from a substantial surface area of the bottom of a fluid storage tank and is adaptable to tanks of varying sizes and shapes.
Another object of the present invention is to provide a contaminant intake that effectively extends along a contoured bottom of a fluid storage tank.
These and other objects, features and advantages of the present invention will become more apparent upon reading the following specification in conjunction with the accompanying drawings.
Referring now in detail to the drawing figures, wherein like reference numerals represent like parts throughout the several views, a sludge removal system 100 of
As illustrated in
The sludge removal system 100 comprises a contaminant removal system 140 and a contaminant retrieval system 150, such that the contaminant retrieval system 150 is adapted to receive contaminants S at the bottom of the storage tank 121 and the contaminant removal system 140 is adapted to transport contaminants S from the contaminant retrieval system 150 to the outside of the storage tank 121 for proper disposal of the removed contaminants S. Together, the contaminant removal system 140 and the contaminant retrieval system 150 ensure that a top level Y of contaminants S does not reach a predetermined level H, which represents the lowest level of fluid F that is drawn by pick-up tube 130.
The contaminant removal system 140 includes a first end in communication with the contaminant retrieval system 150 and a second end in communication with the outside of the storage tank 121. More specifically, the first end of the contaminant removal system 140 can be in communication with the middle of the contaminant retrieval system 150, which is positioned generally perpendicular to the contaminant removal system 140 during the removal of contaminants S from the storage tank 121.
In a preferred embodiment of the present invention, the contaminant removal system 140 comprises a removal member 103, a cam lock 127, and a coupling member 124. The removal member 103 generally includes a hollow core to allow for the transport therethrough of contaminants S from the contaminant retrieval system 150 to the outside of the storage tank 121. The removal member 103 can be a stand pipe or tube that is formed using a variety of suitable, non-corrosive materials including, but not limited to, plastic, carbon steel, rubber, aluminum alloy, and other appropriate material. The length of the removal member 103 depends on the size of the storage tank 121, but has a length sufficient preferably to reach from just above the top of the storage tank 121 to the bottom of the storage tank 121 when aligned vertically.
The coupling member 124, such as a quick-connection coupling, and the cam lock 127 are typically situated near the second end of the removal member 103 (e.g., outside the storage tank 121). The coupling member 124 is adapted to communicate with a suction device (not shown), such as a pump, and suction hose (not shown), such that the suction device provides a negative pressure to the removal member 103 thereby transporting contaminants S from the inside to the outside of the storage tank 121, while the suction hose can be utilized for providing the contaminants S retrieved from the storage tank 121 to a remote storage (not shown) for proper disposal. Additionally, the coupling member 124 is further adapted to communicate with a contaminate filter (not shown) for filtering contaminants from fluid F withdrawn from the storage tank 121, so that the filtered and cleaned fluid F can be returned to the storage tank 121 through an independent return line, such as fluid replenishment line 130. The cam lock 127 is configured to provide security and anti-tampering protection to the sludge removal system 100 being used within the storage tank 121.
Preferably, the contaminant retrieval system 150 comprises a contaminant intake 106 adapted to receive contaminants S from the bottom of the storage tank 121. For example, and not limitation, the contaminant intake 106 can be a suction pipe or tube that is formed using a variety of suitable, non-corrosive materials including, but not limited to, plastic, carbon steel, rubber, aluminum alloy, and other appropriate material. The length of the contaminant intake 106 depends on the size of the storage tank 121, but generally has a length sufficient to reach from one side of the storage tank 121 to the opposing side of the storage tank 121 when aligned horizontally along the bottom of the tank 121.
The contaminant intake 106 can comprise a flange 115 and a coupling end cap 118 positioned at each end of the contaminant intake 106, such that the coupling end cap 118 provides a temporary end and/or thrust relief for the contaminant intake 106, while the flange 115 ensures that the coupling end cap 118 does not detach from the contaminant intake 106 during periods of intense pressure. The suction device connected to the coupling member 124 of the removal member 103 creates sufficient negative pressure for removal of contaminants S and, when flow is reversed, creates sufficient positive pressure for cleaning the removal member 103 and the contaminant intake 106. Accordingly, the flange 115 and coupling end cap 118 assist to keep the pressure within the contaminant intake 106 at an appropriate level.
Additionally, the contaminant intake 106 can include a plurality of joint members 112, such as flexible joints or swivel joints, that are, typically, in communication with the removal member 103 and a portion of the contaminant intake 106. Each joint member 112 is adapted to allow a portion of the contaminant intake 106 to rotationally move between a first position distal to the bottom of the tank 121 and a second position proximate to the bottom of the tank 121. As is described in more detail below, the joint members 112 permit the portions of the contaminant intake 106 to adjust positions when necessary to facilitate various stages of operation of the sludge removal system 100.
The contaminant intake 106 can further comprise a contaminant passage system 160, such that the contaminant passage system 160 is adapted to allow contaminants S to pass from the bottom of the storage tank 121 into the contaminant intake 106. For example, and not limitation, the contaminant passage system 160 comprises a plurality of perforations 109 that allow contaminants S to enter into the contaminant intake 106 from the bottom of the storage tank 121. More specifically, the contaminant intake 106 can be formed to define the plurality of perforations 109, such that the perforations 109 are evenly spaced near, and linearly aligned with, the bottom of the contaminant intake 106. One skilled in the art will recognize that the perforations 109 can be of uniform or varying sizes suitable for the reception of contaminants S, without departing from the scope of the present invention.
In operation, the removal member 103 and contaminant intake 106 are lowered into the storage tank 121 through an opening located at the top of the storage tank 121. The removal member 103 and contaminant intake 106 are submerged into fluid F and lowered into a layer of contaminants S located at the bottom of the storage tank 121. The top layer Y of the contaminants S is located below the top layer X of fluid F, but above the bottom of the storage tank 121. Top layer Y of contaminants S is defined as a varying distance AD above the bottom of the storage tank 121 and depends on various factors such as type, size, and shape of tank 121, as well as the concentration of contaminants located at the bottom of the tank 121.
The portions of the contaminant intake 106 are positioned generally parallel to the bottom of the tank 121 during the removal of contaminants S. As the suction device connected to the removal member 103 via coupling member 124 begins to create a negative pressure within the removal member 103, contaminants S are drawn through the plurality of perforations 109 and into the contaminant intake 106. The removal member 103 then transports the contaminants S from the contaminant intake 106 to the outside of the tank 121 for proper disposal. Accordingly, the removal member 103 and contaminant intake 106 prevent the top layer Y of contaminants S from reaching the bottom (e.g., intake) of the pick-up tube 130 and, therefore, ensures that clean fluid F is drawn from the storage tank 121 through pick-up tube 130.
Typically, the sludge removal system 100 continues to remove contaminants S from the storage tank 121 until the top level Y of the contaminants S is below the predetermined level H or until all contaminants S are substantially removed from the bottom of the storage tank 121. Further, the removal member 103 and the contaminant intake 106 can be cleaned and/or can stir-up the contaminants S on the bottom of the tank 121 by reversing the applied pressure, such as blowing air into removal member 103 via coupling member 124.
The sludge removal system 100 is designed to function temporarily or permanently within standard storage tanks 121. Accordingly, the joint members 112 of the contaminant intake 106, as illustrated in
Although, preferably, the present invention is configured for cylindrical storage tanks 121 having a horizontal alignment, many standard storage tanks 121 include a variety of other shapes and sizes. One skilled in the art will recognize that changes in size, shape, and/or arrangement of the removal member 103 and the contaminant intake 106 may be necessary for each individual storage tank 121. The sludge removal system 100 can be configured to adapt to the differing shapes and sizes of standard storage tanks 121, as illustrated in
Depending upon the size and shape of the storage tank 121, the portions of the contaminant intake 106 may not always be positioned generally parallel to the bottom of the storage tank 121. To facilitate the use of storage tanks 121 with non-flat bottoms, such as the spherical storage tank 121 illustrated in
Storage tanks 121 comprising a flat bottom, such as the rectangular storage tank 121 illustrated in
In another embodiment of the present invention, the removal member 103 can pivot or tilt at the opening located at the top of the rectangular storage tank 121. As the second end of the removal member 103 pivots in one direction, the first end of the removal member 103 moves in the opposite direction.
As the contaminant intake 106 moves from the first, second, and third positions A, B, C, the contaminant intake 106 can remove a substantial amount of contaminants S located along the entire bottom of the tank 121. One skilled in the art will recognize that the removal member 103 can be inserted further into the storage tank 121 as it pivots from the first position A to the second or third position B, C, to maintain the contaminant intake 106 along the flat bottom of the tank 121.
In yet another embodiment of the present invention, the removal member 103 comprises a joint member (not shown) that is adapted to allow the lower portion of the removal member 103 to pivot or tilt and, consequently allows the contaminant intake 106 to move between a first position A located in the middle of the rectangular storage tank 121 to a second position B located near one side of the tank 121 and then to a third position C located near the opposite side of the tank 121. Accordingly, the second end of the removal member 103 remains stationary, while the first end of the removal member 103 in communication with the contaminant intake 106 moves between the first position A, second position B, and third position C.
In still another embodiment of the present invention, the removal member 103, as illustrated in
In another embodiment of the present invention, the contaminant intake 106 remains stationary, instead of moving along the bottom of the rectangular storage tank 121. As illustrated in
The extension members 606 are extensions of the contaminant intake 106 and, therefore, are adapted to receive contaminants S from within the storage tank 121. For example, and not limitation, each extension member 606 can be a suction pipe or tube adapted to receive contaminants S from within the storage tank 121.
Each extension member 606 can comprise a flange 115 and a coupling end cap 118 (similar to that of the contaminant intake 106), which is generally positioned at the second end of the extension member 606. Further, each extension member 606 can include a number of joint members 112, such as flexible joints or swivel joints, which are typically in communication with the contaminant intake 106 and the first end of the extension member 606. Each joint member 112 is adapted to allow the extension members 606, or portions thereof, to adjust positions when necessary to facilitate various stages of operation of the sludge removal system 100. For example, the joint members 112 allow the extension members 606 to extend along a contour of the bottom of the tank 121.
Similar to the contaminant intake 106, each extension member 606 can be formed to define a number of perforations 109, such that each perforation 109 is adapted to receive contaminants S from the storage tank 121. The length of the extension members 606 can vary depending on tank shape and size, but each extension member 606 is generally long enough to cover the distance between the contaminant intake 106, typically positioned at the middle of the tank 121, and one of two opposing sides of the storage tank 121. Accordingly, the extension members 606 enable the contaminant intake 106 to maximize the surface area of the bottom of the rectangular storage tank 121 where contaminants S can be adequately removed by contaminant intake 106.
For example, and not limitation, the contaminant intake 106 comprises a plurality of extension members 606, wherein a subset of the extension members 606 extend outwardly toward a first side of the storage tank 121 and a subset of extension members 606 extend outwardly toward a second side, opposite the first side, of the storage tank 121. Again, the contaminant intake 106 and the extension members 606 remain stationary during operation, because an adequate surface area of the bottom of the storage tank 121 is covered by the contaminant intake 106 and the extension members 606.
To further assist in the configuration of the sludge removal system 100, each portion of the contaminant intake 106 can vary in form, as illustrated in
As illustrated in
As shown in
The flexible joints 112 are sealed to ensure that contaminants S pass efficiently between the portion of the contaminant intake 106 and the removal member 103, as well as to ensure that contaminants S pass efficiently between the subportions 706 of the portion of the contaminant intake 106 during operation.
Instead of a flexible joint 112, the present invention, as illustrated in
As illustrated in
Each slideable subportion 906 comprises a proximal first end and a distal second end, where the proximal first end of the second slideable subportion 906 is adapted to slide from the proximal first end of the first slideable subportion 906 to the distal second end of the slideable subportion 906 (e.g., the extended position) and where the proximal first end of the second slideable subportion 906 is adapted to slide from the distal second end of the first slideable subportion 906 to the proximate first end of the slideable subportion 906 (e.g., the retracted position). One skilled in the art will recognize that each subsequent slideable subportion 906 must have a slightly smaller diameter than the previous slideable subportion 906 to effectively slide within the hollow interior of the previous slideable subportion 906. Additionally, when the telescoping perforated contaminant intake 106 is in the retracted position, the perforations 109 of each slideable subportion 906 align to ensure that the contaminant intake 106 adequately receives contaminants S from the storage tank 121.
In operation, the telescoping perforated contaminant intake 106 is in the retracted position when introduced into the storage tank 121. Upon reaching the contaminants S on the bottom of the tank 121, the slideable subportions 906 of the contaminant intake 106 slide outwardly until the contaminant intake 106 is in the extended position. Depending on the size of the storage tank 121 or the contour of the bottom of the storage tank 121, the telescoping perforated contaminant intake 106 may not be able to fully extend, but will extend as far as possible to adequately cover the bottom of the storage tank 121. One skilled in the art will recognize that the slideable subportions 906 of the contaminant intake 106 can be activated through a mechanical device, such as a hydraulic piston, or though the positive and negative pressure provided by the pump (not shown).
The contaminant intake 106 can further comprise a number of scraping members 1003, as illustrated in
Each scraping member 1003 is generally aligned with a perforation 109 of the contamination intake 106, thus each scraping member 1003 directs loosened contaminants S towards the perforation 109 during operation. The scraping members 1003 can include, but are not limited to, brushes, scrapers, wedges, blades, or other appropriate abrasive materials capable of loosening contaminants S attached to the bottom of the storage tank 121.
Numerous characteristics and advantages have been set forth in the foregoing description, together with details of structure and function. While the invention has been disclosed in several forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions, especially in matters of shape, size, and arrangement of parts, can be made therein without departing from the spirit and scope of the invention and its equivalents as set forth in the following claims. Therefore, other modifications or embodiments as may be suggested by the teachings herein are particularly reserved as they fall within the breadth and scope of the claims here appended.
This application claims priority of U.S. Provisional Patent Application No. 60/682,659, filed 19 May 2005, the entire contents of which is hereby incorporated by reference.
Number | Date | Country | |
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60682659 | May 2005 | US |