WO2018185219A1

WO2018185219A1 - A device and method for cleaning interior surfaces of tanks and containers

Info

Publication number: WO2018185219A1
Application number: PCT/EP2018/058725
Authority: WO
Inventors: Kaare Wessel Wetlesen; Ole Meldgaard Nielsen
Original assignee: Oreco A/S
Priority date: 2017-04-07
Filing date: 2018-04-05
Publication date: 2018-10-11
Also published as: EP3385003A1

Abstract

A cleaning device (1) for cleaning interior surfaces of containers, such as oil-tanks, the cleaning device comprises: a flushing liquid inlet pipe (3) for the supply of liquid; an extended flushing liquid pipe (4), extending vertically from an upper position of the oil tank and downwardly to the bottom (5) of the oil-tank and being in fluid communication with the flushing liquid inlet pipe (3); a nozzle hub (6) arranged at the distal end of the extended flushing liquid pipe (4), so as to form a fluid connection between the (4) nozzle hub (6) and a nozzle (7); one or more nozzles (7), arranged on the nozzle hub (6), configured for discharging jets of flushing liquids against walls and bottom of said oil-tank; the cleaning device (1) being arranged between a wall (8) of the oil-tank and a rim seal (10) of a floating roof (9) of the oil-tank.

Description

A DEVICE AND METHOD FOR CLEANING INTERIOR SURFACES OF TANKS AND CONTAINERS

FIELD OF THE INVENTION

The present invention relates to a cleaning device for cleaning interior surfaces of containers, such as oil-tanks.

BACKGROUND OF THE INVENTION

A tank cleaning machine is a machine used to clean e.g. cargo, process, underground storage containers and oils tanks. Oil tanks, in particular, must be cleaned on regular basis, primary to remove hazardous waste generated from tank bottoms, also referred to as sludge. Sludge is a common name for deposits of impurities found at the bottom of the oil tank, and represents a multitude of various pollution particles.

The invention relates to tank cleaning equipment, especially for oil tanks. Cleaning of an oil tank is typically done by means of a pipe lowered into the tank space, usually through the Internal Floating Roof of the oil tank. The tank-cleaning device typically comprises a liquid-pipe for supply of the flushing liquid to a flushing liquid pipe, which has at least one flushing nozzle for discharging the flushing liquid. A switch device is typically provided to bring the pipes and/or the nozzles to rotate around its axis. A control device is typically also provided to control the rotation of the liquid pipe and the flushing nozzle. Material settled on the tank wall and bottom and the cleaning medium are afterwards pumped out, to an external location to the tank.

A problem occurs, when sludge is accumulated along the wall and where different internal structures are present. The up to date cleaning device does not clean these places efficiently.

An improved tank cleaning device and method for cleaning sludge accumulated along the wall and where different internal structures are present would be advantageous. OBJECT OF THE INVENTION

An object of the present invention is to provide an alternative to the prior art.

In particular, it may be seen as an object of the present invention to provide a device and method for cleaning sludge accumulated along the wall and where different internal structures are present.

SUMMARY OF THE INVENTION

The invention relates, in a first aspect, to a cleaning device for cleaning interior surfaces of containers, such as oil-tanks, the cleaning device comprises:

- a flushing liquid inlet pipe for the supply of liquid;

- an extended flushing liquid pipe, extending vertically from an upper position of the oil tank and downwardly to the bottom of the oil-tank and being in fluid communication with the flushing liquid inlet pipe;

- a nozzle hub arranged at the distal end of the extended flushing liquid pipe, so as to form a fluid connection between the nozzle hub and a nozzle;

- one or more nozzles, arranged on the nozzle hub, configured for

discharging jets of flushing liquids; wherein

- the cleaning device being arranged between a wall of said oil-tank and a rim seal of a floating roof of said oil-tank,

The cleaning device may further comprise a raising/lowering system, to adjust a position of the nozzle hub above the bottom of the oil tank.

The cleaning device may further comprise a nozzle tip, preferably being

replaceable arranged at the distal end of the nozzle. The nozzle hub is preferably rotatable around an axis being perpendicular to a longitudinal direction of a vertical axis.

The nozzle may be configured for moving vertically and horizontally.

The nozzle may be configured to rotate between two outer most positions, with an adjustable speed which allows for an vertical washing angel change of 40 degrees, such as lower than 30, preferably lower than 20 degrees. The nozzle hub may comprise one nozzle, such as two nozzles, preferably two or more nozzles.

When the cleaning device comprises two nozzles, the two nozzles may preferably be positioned 180 degrees opposite to each other and each preferably be configured for movement in a horizontal and vertical direction simultaneously.

When the cleaning device comprises two nozzles, the two nozzles may preferably be configured for movement in a horizontal and vertical direction simultaneously as mirror of each other seen from the vertical axis.

The nozzle may be configured for being turned 90 degrees downwardly to enter the oil tank through the pre-installed openings in the oil tank wall being placed in a horizontal position. The cleaning device may further comprise a hydraulic driver control box, configured for controlling said cleaning device.

Preferably, the cleaning device further comprises support elements, such as supporting legs, preferably being arranged on the nozzle hub, configured for supporting the cleaning device to stand on bottom of the oil tank.

The cleaning device may further comprise an adjustable seal, preferably being arranged around the area of between the cleaning device, the floating roof of the oil-tank and wall, to secure an airtight seal. The cleaning device may further comprise a PLC control box, configured for controlling the movement of the nozzle(s).

The cleaning device is preferably configured for use for removing sludge accumulated along the wall and where different internal structures are present.

In a second aspect, the present invention relates to a method of cleaning of interior surfaces. The method preferably utilize a mounting of a cleaning device between wall and floating roof on an oil tank to be cleaned.

The method according to the second aspect of the invention may thus comprise, mounting a cleaning device according to the first aspect of the invention between one or more walls and floating roof on an oil tank to be cleaned.

In the present context a number of terms are used in a manner being ordinary to the skilled person. Some of these terms are detailed below:

Floating Roof is preferably meant to denote a roof top, floating on the liquid within the tank and rising and falling with the liquid level. One purpose of the internal floating roof is to minimize the gaseous zone above the stored liquid.

Cleaning area is preferably meant to denote an area interior to the oil tank to be cleaned.

Nozzle jet is preferably meant to denote a stream of fluid discharged from a nozzle.

Nozzle sweeper is preferably meant to denote a cleaning device according to the present invention. The aspects and embodiments of the present invention may each be combined with any of the other aspects and embodiments. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE FIGURES The present invention and in particular preferred embodiments thereof will now be disclosed in greater details with reference to the accompanying figures. The figures show ways of implementing the present invention and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 is a schematically view of a cleaning device according to the present invention. Figure 2 is a schematically view of a nozzle hub according to the present invention.

Figure 3 is a schematically view of a cleaning device according to the present invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

Reference is made to figure 1 illustrating a cleaning device 1 for cleaning interior surfaces of containers, such as oil-tanks. The cleaning device 1 comprises a flushing liquid inlet pipe 3 for the supply of liquid; an extended flushing liquid pipe 4, extending vertically from an upper position of the oil tank and downwardly to the bottom 5 of the oil-tank and being in fluid communication with the flushing liquid inlet pipe 3; a nozzle hub 6 arranged at the distal (distal to the proximal end at the flushing inlet pipe 3) end of the extended flushing liquid pipe 4), so as to form a fluid connection between the 4 nozzle hub 6 and a nozzle 7; two nozzles 7, arranged on the nozzle hub 6, configured for discharging jets of flushing liquids.

The extended flushing liquid pipe 4 is arranged between a wall 8 of the oil-tank and a rim seal 10 of a floating roof 9 of the oil-tank.

During operation, the nozzles 7 discharges jets of flushing liquids against the oil tank walls and bottom and hereby cleaning the interior, such as the interior surface, of the oil tank. The cleaning device may further comprises a raising/lowering system (not shown in the figures). This raising/lowering system enables a control of the position of the nozzle hub 6 above the bottom of the oil tank, to ensure a larger cleaning area interior to the oil tank. Later, during cleaning operation, the sweeper can be raised/lowered by means of adjusting the support leg. This is not done

automatically.

The nozzle 7 preferably comprises a nozzle tip 11, being replaceable arranged at the distal end of the nozzle 7, so as to adapt for each specific tank design. During operating mode, the nozzle hub 6 is rotatable around an axis being perpendicular to a longitudinal direction of a vertical axis 2, as illustrated in figure 1. The rotation of the nozzle hub 6 ensures a larger cleaning impact zone for the nozzle jets. The nozzle 7 is preferably configured for moving vertically and horizontally. This ensures a larger cleaning impact zone, to obtain an efficient cleaning of the interior of the oil tank and to ensure that the nozzle jet reach the centre of the oil tank. Reference is now made to figure 2 illustrating a nozzle hub 6 according to the present invention.

In figure 2 two nozzles 7 are disclosed as being mounted on the nozzle hub 6. The nozzles 7 are configured to rotate between two outer most positions, with an adjustable speed which allows for an vertical washing angle 16 change of 40 degrees, such as lower than 30, preferably lower than 20 degrees.

The two nozzles 7 are positioned 180 degrees opposite to each other and have movement in both horizontal and vertical direction simultaneously and also as a mirror of each other seen from the vertical axis.

The movement of the nozzles may be done by a nozzle hub 6 with two nozzles 180 degree split, and with the whole nozzle hub 6 rotating around a horizontally axis. In another embodiment, the movement of the nozzles may be done by a static nozzle hub 6 with two nozzles 180 degree split and the two nozzles turning synchronically. In another embodiment, the nozzle movement is done by the two nozzles moving synchronously towards each other, and out again. That is, the nozzles do not remain 180 degrees with respect to each other, but the angle is reduced to a certain point, and then the nozzles moves back to 180 degrees displacement. Additional nozzles 7 may be installed on the nozzle hub 6 allowing for other directions of cleaning angles.

By moving the nozzles 7, which have exchangeable nozzle tips, both vertically and horizontally it is possible to clean the tank wall, the corner between tank wall and tank bottom as well as cleaning the tank floor towards the centre of the tank.

Additional nozzles 7 may be installed on the same nozzle hub 6.

The nozzle 7 is configured for being turned 90 degrees downwardly to enter the oil tank through the pre-installed openings in the oil tank wall 8 being placed in a horizontal position.

In figure 3 the nozzle sweeper is schematically illustrated as stand-alone (without tank wall, floating roof and adjustable seal illustrated). The nozzle sweeper comprises a single nozzle 7 on figure 3.

The nozzle sweeper comprises a hydraulic driver control box 12 and hydraulic motor (not shown in the figures), configured for controlling the nozzle movement. In this way limitation can be introduced and secure a desirable nozzle washing angle along the interior of the oil tank.

The flushing liquid may be drawn from the existing tank cleaning system, which is connected to the flushing liquid inlet pipe 3. The nozzle sweeper may further comprise support elements 13, such as supporting legs, being arranged on the nozzle hub 6. The supporting legs are configured for supporting the cleaning device 1 to stand on the bottom 5 of the oil tank, stabilising the cleaning device in particularly during operation mode. The support leg is preferably adjusted prior to installation. Turning back to figure 1, the cleaning device preferably comprises an adjustable seal 14, being arranged around the area of between the cleaning device 1, the floating roof 9 of the oil-tank and wall 8. The adjustable seal 14 secures an airtight seal. The nozzle sweeper is fixed on the tank shell with a temporary secure connection and the adjustable seal 14 arranged around the area of penetration of the nozzle sweeper, to secure an airtight seal that will prevent nitrogen from inside the oil tank to escape to the exterior.

The cleaning deice further comprises a hydraulic driver control box 12, configured for controlling the movement of the nozzle(s) 7.

The nozzle sweeper is powered by a hydraulic motor (not shown in the figures) similar to existing nozzle sweeper, and not by electric driven equipment.

Controlling the movement of the nozzle extension will be done by the PLC equipment and connected to existing tank cleaning system.

The cleaning device, according to the present invention, is preferably configured for use for removing sludge accumulated along the oil tank wall and where different internal structures are present. The nozzle sweeper is preferably fixed in the position between the tank wall and rim seal by way of temporary secure connection on the tank wall. The nozzle sweeper has a construction that allows for a structural member at the bottom of the nozzle sweeper reaching to the bottom inside the oil tank. As an effect of the positioning of the nozzle sweeper between the tank wall and rim seal, the cleaning device according to the present invention is particular suited for cleaning operations in floating roof tanks where sludge and waste material has accumulated along the wall and where different internal structures are present. The positioning of the nozzle sweeper between the tank wall and rim seal, efficiencies the cleaning of the oil tank walls and enhances the covering of the interior surface cleaning area, so as to optimize the recovery of hydrocarbons. In another embodiment of the present invention, the nozzle sweeper is configured for moving peripherally around the oil tank.

In another aspect the invention relates to a method of cleaning of interior surfaces. The method utilize a mounting of a cleaning device between an oil tank wall 8 and floating roof 9 on an oil tank to be cleaned.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

LIST OF REFERENCES

1 : Cleaning device

2: Vertical axis

3: Flushing liquid inlet pipe

4: Extended flushing liquid pipe

5: Bottom of the oil-tank

6: Nozzle hub

7: Nozzle

8: Wall of the oil tank

9: Floating roof of oil tank Rim seal

Nozzle tip

Hydraulic driver control box

Support element

Adjustable seal

Drive shaft

Vertical washing angle

Claims

1. A cleaning device (1) for cleaning interior surfaces of containers, such as oil- tanks, the cleaning device comprising

- a flushing liquid inlet pipe (3) for the supply of liquid;

- an extended flushing liquid pipe (4), extending vertically from an upper position of an oil tank and downwardly to the bottom (5) of said oil-tank and being in fluid communication with said flushing liquid inlet pipe (3);

- a nozzle hub (6) arranged at the distal end of said extended flushing liquid pipe (4), so as to form a fluid connection between said nozzle hub (6) and one and more nozzles (7);

- said one or more nozzles (7), arranged on said nozzle hub (6),

configured for discharging jets of flushing liquids against walls and bottom of said oil-tank, thereby cleaning the interior of said oil tank; wherein

- said cleaning device (1) being arranged between a wall (8) of said oil- tank and a rim seal (10) of a floating roof (9) of said oil-tank,

2. A cleaning device according to claim 1, further comprising a raising/lowering system, to adjust a position of said nozzle hub (6) above the bottom (5) of said oil tank.

3. A cleaning device according to claim 1 or 2, further comprising a nozzle tip (11), being replaceable arranged at the distal end of said nozzle (7).

4. A cleaning device according to any of the preceding claims, wherein said nozzle hub (6) is rotatable around an axis being perpendicular to a longitudinal direction of a vertical axis (2).

5. A cleaning device according to any of the preceding claims, wherein said nozzle (7) is configured for moving vertically and horizontally.

6. A cleaning device according to any of the preceding claims, wherein said nozzle(7) is configured to rotate between two outer most positions, with an adjustable speed which allows for an vertical washing angle (16) change of 40 degrees, such as lower than 30, preferably lower than 20 degrees.

7. A cleaning device according to any of the preceding claims, wherein said nozzle hub (6) comprises one nozzle (7), such as two nozzles (7), preferably two or more nozzles (7).

8. A cleaning device according to any of the preceding claim 7, wherein the two nozzles (7) are positioned 180 degrees opposite to each other and each are configured for movement in a horizontal and vertical direction simultaneously, or as a mirror of each other seen from the vertical axis.

9. A cleaning device according to any of the preceding claims, wherein the nozzle (7) is configured for being turned 90 degrees downwardly to enter said oil tank through a pre-installed openings in the oil tank wall (8) being placed in a horizontal position.

10. A cleaning device according to any of the preceding claims, further comprising a hydraulic driver control box (12), configured for controlling said cleaning device (1).

11. A cleaning device according to any of the preceding claims, further comprising support elements (13), such as supporting legs, being arranged on said nozzle hub (6), configured for supporting said cleaning device (1) to stand on bottom (5) of said oil tank.

12. A cleaning device according to any of the preceding claims, further comprising an adjustable seal (14), being arranged around the area of between the cleaning device (1), the floating roof (9) of said oil-tank and wall (8), to secure an airtight seal.

13. A cleaning device according to any of the preceding claims, further comprising a PLC control box, configured for controlling the movement of said nozzle(s) (7).

14. A method of cleaning of interior surfaces, said method comprising mounting a cleaning device according to claims 1-13 between one or more walls (8) and floating roof (9) on an oil tank to be cleaned.