|
(11) | EP 2 942 117 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||||||
| (54) | IMPROVED CLEANING SYTEM |
| (57) System and method for cleaning sediments and sludge deposits from inside very large
fluid containers, such as oil or fuel oil tanks, by providing an array of pipelines
with multiple inlets distributed across the tank base. The pipework arrangement converges
to a single outlet which can be attached to a machine to suck out sludge and other
deposits from within the tank. The cleaning is then carried out at greater speed than
with conventionally used methods. This system is also inherently safer than the systems
currently employed because it avoids human exposure to dangerous vapours and liquids.
|
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and a method of cleaning fuel oil, particularly but not exclusively, the present invention relates to a method and apparatus of cleaning fuel oil in industrial tanks.
BACKGROUND TO THE INVENTION
[0002] One of the problems of storing oil in tanks is the build-up of sludge and rust at the bottom of the tank with time. This sludge and rust settles as a contaminated layer and conventional tanks cope with this problem by extracting oil from the tank at a level which is above and spaced away from the contaminated layer.
[0003] However, when fresh oil is introduced to the tank, this can stir up the sludge and rust contaminating the fuel oil for a period of time until it has settled, and over time, the contaminated layer may build-up to an extent which requires the tank to be drained and cleaned as the build-up is impinging on the extraction outlet.
[0004] The cleaning of the tank generally involves one or two people going into the tank and manually removing the sludge using shovels and buckets or by using a suction hose.
[0005] This is time consuming and dangerous and requires for the tank to be drained with the potential loss or a large amount of fuel oil.
SUMMARY OF THE INVENTION
[0006] According to a first aspect of the present invention there is provided a system for cleaning a tank, the system comprising;
a pipework arrangement adapted to be positioned adjacent to the base of a tank to be cleaned, the pipework arrangement defining a plurality of inlets, and
an outlet pipe, the outlet pipe providing fluid communication between the pipework arrangement and, in use, a tank outlet;
wherein, in use, the pipework is adapted to extend across the length and breadth of at least a portion of the base of the tank.
[0007] In at least one embodiment of the present invention, providing a system for cleaning the tank as described above, allows for faster cleaning of the tank due to the extent of the pipework and the use of multiple inlets to remove sludge and contamination that may have settled at the bottom of the tank..
[0009] The pipework arrangement may comprise at least one primary pipework arrangement pipe, the/each primary pipework arrangement pipe adapted to run substantially parallel to a major axis of the tank.
[0010] The/each primary pipe may be connected to at least one secondary pipework arrangement pipe, the/each secondary pipework arrangement pipe attached at an angle the primary pipework arrangement pipe or one of the primary pipework arrangement pipes. The arrangement of pipework arrangement pipes may be similar to a spine and ribs.
[0013] The/each secondary pipework arrangement pipe first end may be connected to the primary pipework arrangement pipe.
[0015] At least some of the pipework arrangement pipes' second ends may define a pipework arrangement reach.
[0018] In some embodiments the system footprint may cover more than 70% of the base of the tank to be cleaned.
[0019] In still further embodiments, the system footprint may cover more than 90% of the base of the tank to be cleaned. For a rectangular tank the base is the lowest surface parallel to the ground upon which the tank is mounted. For a tank with a curved surface, the base is defined by the lower half of the tank up to a height of approximately 20% of the tank radius.
[0030] In further additional or alternative embodiments, the pipework arrangement pipes may be connected by a push fit.
[0033] Additionally or alternatively, each secondary pipework arrangement pipe may comprise a number of pipe sections
[0035] The system may be permanently installable within a tank. Although the system may be removed, and preferred embodiment would see the system being permanently installed in a tank.
[0036] The pipework arrangement pipes may comprise a plurality of pipe sections. Sections of pipe can be used to make up the longer pipework arrangement pipes to facilitate installation.
[0038] One pipe section may be releaseably connected to another pipe section by means of a quick release clamp, a threaded connection, a push fit connection or any suitable releasable connection means.
[0039] The outlet pipe, in use, may extend from the pipework arrangement to an upper surface of the tank. In some installations, an outlet has to be created in the tank to provide a flowpath from the system to the tank exterior. It is preferred to have this outlet located above the surface of the oil or fuel that is within the tank to remove the possibility of leakage around the outlet.
[0041] The upper section may be define a connection, the connection adapted to be connected to a tank outlet.
[0042] The connection may also be adapted to be connected to a fuel cleaning apparatus. A fuel cleaning apparatus is used to suck the fuel in sludge from the bottom of the tank and process it to remove the contaminants from the fuel. This fuel can either be returned to the tank or disposed of with the contaminants.
[0045] The lower pipe section be may be connected to the upper pipe section by a flexible portion. A flexible portion may be provided to facilitate installation and compensate for a misalignment between the tank outlet and the pipework arrangement connection.
[0049] The inlet holes may be located on the underside of at least a portion of the pipework arrangement.
[0050] Alternatively or additionally, the inlet holes may be located on the side of at least a portion of the pipework arrangement.
[0051] In preferred embodiments, the inlet holes may be located on both the side and underside of at least a portion of the pipework arrangement.
[0052] In a particularly preferred embodiment, the inlet holes may be located on the sides and undersides of the secondary pipework arrangement pipes.
[0053] The system may comprise a return pipework arrangement for returning the filtered and/or clean fuel to the tank. In at least one embodiment of the present invention a return pipework arrangement provides a suitable way to return the clean fuel to the tank.
[0054] For clarity, the pipework arrangement for removing contaminated fuel will be called primary or suction pipework arrangement and the pipework arrangement for returning the fuel into the tank will be called return pipework arrangement.
[0055] The return pipework arrangement may be adapted to be positioned adjacent to the base of the tank to be cleaned, may define a plurality of outlets and may comprise an inlet pipe, the inlet pipe providing fluid communication between the pipework arrangement and, in use, a fuel cleaning apparatus wherein, in use, the return pipework arrangement is adapted to extend across the length and breadth of at least a portion of the base of the tank.
[0056] In at least one embodiment of the present invention a return pipework arrangement located adjacent the base of the tank uses the return fuel flow to enhance the mobilisation of the sludge at the bottom of the tank, such that the rate at which the cleaning proceeds can be increased and the system can clean or remove even denser sediments.
[0057] The return pipework arrangement may comprise features equivalent to those of the primary pipework arrangement and are not repeated for brevity.
[0058] The system may comprise formations located adjacent the base of the tank for dividing the base of the tank in two or more sections. In at least one embodiment of the present invention a division of the tank base allows to concentrate the cleaning operations in each or some of the sections, thus concentrating the suction power to one or a few sections at a time.
[0059] The formations may comprise baffles running along the major axis of the tank. In at least one embodiment of the present invention the baffles are simple structural elements that can divide up the tank base in sections and confine the suction action in one or a few sections.
[0060] The system may be configured that each section of the tank base may contain at least a portion of the suction pipework arrangement and at least a portion of the return pipework arrangement. In at least one embodiment of the present invention when a section comprises a section of suction pipe and a section of return pipe, the suction effect can be combined with the mobilising effect of the return fuel flow and be confined in a section of the tank base to improve the cleaning effect of the system.
[0061] The primary or suction pipework arrangement may comprise valves for confining the cleaning of the tank to a portion of the pipework arrangement.
[0062] The return pipework arrangement may comprise valves for confining the cleaning of the tank to a portion of the return pipework arrangement.
[0063] According to a second aspect of the present invention there is provided a method of cleaning a tank, the method comprising the steps of;
assembling a pipework arrangement adjacent the base of a tank to be cleaned; connecting the pipework arrangement to a tank outlet;
applying a suction to the outlet pipe and pipework arrangement such that contaminated fuel oil is sucked through a plurality of pipework arrangement inlets, into the pipework arrangement and from the pipework arrangement contaminated fuel oil is sucked out of the tank outlet via the outlet pipe.
[0065] The step of cleaning the contaminated fuel oil may comprise the step of filtering the fuel oil.
[0067] The method may comprise the step of mobilising the sediments on the bottom of the tank with a return flow of fuel oil into the tank.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] Embodiments of the present invention will now be described with reference to the accompanying drawings in which:
Figure 1 is an end view of a system for cleaning a tank according to a first embodiment of the present invention
Figure 2 is a side view of the system of Figure 1;
Figure 3 is a plan view of the system of Figure 1;
Figure 4 is an enlarged side view of part of the system of Figure 1;
Figure 4a is a close up view of part of Figure 4;
Figure 5 is a system for cleaning a tank according to a second embodiment of the present invention;
Figure 6 is a side view of the system of Figure 5;
Figure 7 is a plan view of the system of Figure 5; and
Figure 8 is a close up end view of part of the system of Figure 5.
Figure 9 is a perspective view of a system for cleaning a tank comprising a return pipework arrangement according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0069] Reference is first made to Figure 1, Figure 2 and Figure 3, end side and plan views respectively of a system, generally indicated by reference numeral 10 for cleaning an industrial fuel tank 12 according to a first embodiment of the present invention. The tank 12 is shown in section to allow the features of the cleaning system 10 to be seen clearly.
[0070] The cleaning system 10 comprises a pipework arrangement 14 positioned adjacent the base 16 of the tank 12. The pipework 14 comprises a primary pipework arrangement pipe 18 located along a major axis 20 of the tank 12 and a large number of secondary pipework arrangement pipes 22 extending at right angles to the primary pipework arrangement pipe 18 across the width 24 of the tank 12.
[0071] The primary pipework arrangement pipe 18 is made up with a number of sections of pipe 58, the pipe sections 58 connected by quick release clamps 56.
[0072] Each secondary pipework arrangement pipe 22 has a first end 26 and a second end 28. Each secondary pipework arrangement pipe first end 26 is connected to, and is in fluid communication with, the primary pipework arrangement pipe 18 and each secondary pipework arrangement pipe second end 28 is blanked off and this distal from the primary pipework arrangement pipe 18, in this embodiment, each secondary pipework arrangement pipe second end 28 being adjacent the side wall 30 of the tank 12.
[0073] Referring particularly to Figure 3, the primary pipework arrangement pipe 18 also has a first end 34 and a second end 38. The primary pipework arrangement pipe first end 34 is connected to an outlet pipe 36 and the primary pipework arrangement pipe second end 38 is blanked off and is distal from the outlet pipe 36.
[0074] The pipework arrangement 14 forms a two dimensional array of the pipework arrangement pipes 18, 22, and the second ends 28, 38 of the pipework arrangement pipes 18, 22 define a footprint 32 (shown in broken outline) indicating the extent of the two dimensional array of the pipework arrangement 14. This footprint 32, as can be seen from Figure 3 extends to more than 90% of the surface of the base 16 of the tank 12.
[0075] The outlet pipe 36 comprises a lower portion 40, an upper portion 42 and a flexible portion 44. The flexible outlet pipe portion 44 connects the lower outlet pipe portion 40 to the upper outlet pipe portion 42. The outlet pipe sections 40, 42, 44 are also connected by quick release clamps 56.
[0076] The outlet pipe 36 is connected to a tank outlet 48 by and outlet pipe connection 50. The system 10 therefore provides fluid communication between the pipework arrangement 14 and the tank outlet 48.
[0077] Reference is now made to Figure 4, an enlarged side view of part of the system 10 of Figure 1, and Figure 4a, a close up view of part of Figure 4. These Figures show the part of the system 10 in the vicinity of the connection 54 between the primary pipework arrangement pipe 18 and the outlet pipe 36. The view in Figure 4 shows the tank 12 in use storing fuel 72 with a layer of contaminants 74 along the tank base 16
[0078] As can be seen from Figures 4 and 4a, the secondary pipework arrangement pipes 22 are suspended underneath the primary pipework arrangement pipe 18 to bring them into close proximity with the base 16 of the tank 12 to maximise the system's 10 ability to suck the contaminants out of the tank. The pipework arrangement secondary pipes 22 are straight, to maintain the close proximity to the tank base 16
[0079] The secondary pipework arrangement pipes 22 are connected to the primary pipework arrangement pipe 18 by further quick release clamps 56 and, similarly, the primary pipework arrangement pipe 18 is connected to the outlet pipe 36 by a quick release clamp 56.
[0080] Referring particularly to Figure 4a, the secondary pipework arrangement pipes 22 define a number of downward facing inlet holes 60 and a number of sideward facing inlet holes 62 adapted to allow the extraction of the contaminated fuel oil layer 74 from beneath clean fuel oil layer 72 from the base of the tank 12 through the pipework arrangement 14 and the outlet pipe 36 under the influence of a suction force applied by an apparatus (not shown) connected to the tank outlet 48.
[0081] The use of sections of pipe 18, 22, 58 connected together with quick release clamps 56 allows for the system 10 to be assembled within the tank 12 on site.
[0082] Referring to Figures 1 to 4a, to install the system 10, the tank 12 is first drained of as much of the fuel oil 72 above the contaminated fuel oil layer 74 in the bottom of the tank 12 as is possible. The sections of pipe 18, 22, 58 are lowered through an access hatch 64 into the tank 12 and assembled in a preferred arrangement using the quick release clamps 56. The tank outlet 48 is cut in the tank at a position directly above the outlet pipe lower portion 40, the outlet pipe upper portion 42 being connected to the tank outlet 48 by the connection 50. Any misalignment between the upper and lower outlet pipe portions 40, 42 is compensated for by the flexible outlet pipe portion 44.
[0083] Once the system is installed, a fuel oil cleaning apparatus (not shown) can be connected to the tank outlet 48 and the outlet pipe connection 50 and a contaminant/fuel oil mix at the bottom of the tank 12 can be removed with minimal disturbance to the fuel oil above. This contaminant/fuel oil mix can be cleaned and the resulting cleaned fuel oil returned to the tank 12.
[0084] Reference is now made to Figures 5 to 8, showing various views (described above) of a system 110 for cleaning a tank 112 according to a second embodiment of the present invention.
[0085] In this embodiment, the system 110 is largely the same as the system 10 of the first embodiment and operates in the same way. The essential difference being that the tank 112 has a circular cross-section and, accordingly, the secondary pipes 122 are curved (Figure 8) to follow the contour of the tank base 116. A thicker contaminated oil layer 174 is formed at the bottom 16 of the tank 112. As well as being thicker, the contaminated fuel layer 174 is also narrower due to the curve of the tank sides 180 than the contaminated fuel layer 74 of a straight sided tank 12, of the sort shown in Figures 1 to 4, having the same volume. This design means the secondary pipes 122 can be shorter than the pipes 22 of the first embodiment and still capture the contaminant layer.
[0086] In Figure 9 a system 210 for cleaning a tank 212 comprising a return pipework arrangement 230 is represented. This system 210 comprises a primary pipework arrangement 214 for removing contaminated fuel from the tank 212. The contaminated fuel is sent to a fuel cleaning and filtering unit (not shown) and then the cleaned fuel is sent back to the tank 212 through the return pipework arrangement 230. The system 210 also comprises baffles 232 arranged adjacent the base of the tank 212. The baffles 232a, 232b divide the base of the tank in three sections 234a, 234b and 234c. In each section 234a, 234b, 234c there is a branch of the primary pipework arrangement 214a, 214b, 214c and a branch of the return pipework arrangement 230a, 230b and 230c. The return flow of the clean fuel is represented by dark arrows 236 and it helps mobilise the sludge and sediments (not shown) deposited at the bottom of the tank 212 so that the sludge can be suctioned trough the primary pipework arrangement 214 completely and at greater speed. The flow of the contaminated fuel is represented by the clear arrows 238.
[0087] Various modifications and improvements may be made to the above described embodiment without departing from the scope of the invention. For example, although quick release clamps are shown for connecting the pipe lengths together, equally the pipes could be threaded together or some sort of push fit connection utilised.
1. A system for cleaning a tank, the system comprising;
a pipework arrangement adapted to be positioned adjacent to the base of a tank to be cleaned, the pipework arrangement defining a plurality of inlets, and
an outlet pipe, the outlet pipe providing fluid communication between the pipework arrangement and, in use, a tank outlet;
wherein, in use, the pipework is adapted to extend across the length and breadth of at least a portion of the base of the tank.
a pipework arrangement adapted to be positioned adjacent to the base of a tank to be cleaned, the pipework arrangement defining a plurality of inlets, and
an outlet pipe, the outlet pipe providing fluid communication between the pipework arrangement and, in use, a tank outlet;
wherein, in use, the pipework is adapted to extend across the length and breadth of at least a portion of the base of the tank.
2. A system according to claim 1 wherein the pipework arrangement comprises at least
one primary pipework arrangement pipe, the/each primary pipework arrangement pipe
adapted to run substantially parallel to a major axis of the tank.
3. A system according to claim 2 wherein the/each primary pipe is connected to at least
one secondary pipework arrangement pipe, the/each secondary pipework arrangement pipe
being attached at an angle to the primary pipework arrangement pipe or one of the
primary pipework arrangement pipes.
4. A system according to claim 2 or claim 3 wherein each pipework arrangement pipe has
a first end and a second end.
5. A system according to claim 4 wherein at least some of the pipework arrangement pipes'
second ends define a pipework arrangement reach.
6. A system according to claim 5 wherein the pipework arrangement reach defines a system
footprint and the system footprint, in use, covers more than 50% of the base of the
tank to be cleaned.
7. A system according to any of claims 2 to 6 wherein the pipework arrangement pipes
are releaseably connected together.
8. A system according to claim 7 wherein the pipework arrangement pipes are connected
by quick release clamps.
9. A system according to any preceding claim wherein the outlet pipe comprises an upper
section and a lower section and the lower pipe section is connected to the upper pipe
section by a flexible portion.
10. A system according to any preceding claim comprising a return pipework arrangement
for returning filtered and/or clean fuel to the tank, the return pipework arrangement
being adapted to be positioned adjacent to the base of the tank to be cleaned, to
define a plurality of outlets and comprises an inlet pipe, the inlet pipe providing
fluid communication between the return pipework arrangement and, in use, a fuel cleaning
apparatus wherein, in use, the return pipework arrangement is adapted to extend across
the length and breadth of at least a portion of the base of the tank.
11. A system according to any preceding claim comprising formations located adjacent the
base of the tank for dividing the base of the tank in two or more sections.
12. A system according to claim 11 wherein the formations comprise baffles running along
a major axis of the tank.
13. A system according to claim 11 or claim 12 being configured such that each section
of the tank base contains at least a portion of the suction pipework arrangement and
at least a portion of the return pipework arrangement.
14. A system according to any preceding claim comprising valves for confining the cleaning
of the tank to a portion of the pipework arrangement or to a portion of the return
pipework arrangement.
15. A method of cleaning a tank, the method comprising the steps of;
assembling a pipework arrangement adjacent the base of a tank to be cleaned; connecting the pipework arrangement to a tank outlet;
applying a suction to the outlet pipe and pipework arrangement such that contaminated fuel oil is sucked through a plurality of pipework arrangement inlets, into the pipework arrangement and from the pipework arrangement contaminated fuel oil is sucked out of the tank outlet via the outlet pipe.
assembling a pipework arrangement adjacent the base of a tank to be cleaned; connecting the pipework arrangement to a tank outlet;
applying a suction to the outlet pipe and pipework arrangement such that contaminated fuel oil is sucked through a plurality of pipework arrangement inlets, into the pipework arrangement and from the pipework arrangement contaminated fuel oil is sucked out of the tank outlet via the outlet pipe.