JPH0967021A | 1997-03-11 |
Claims 1. Installation for unloading a bulk good from a vessel with a hold which delimits a volume in which the bulk good can be held, wherein the installation comprises a frame with support legs for placing the installation on edges of an opening at the position of an upper side of the hold, wherein the installation further comprises a central throughfeed element which is connected to the frame and extends at least downward therefrom in order to be carried through the opening and into the frame, wherein the installation further comprises a mechanism for pneumatic conveying of the bulk good, wherein the mechanism comprises a connecting pipe which extends through the central throughfeed element and up to a lower section of the central throughfeed element and comprises a pipe system which is connected to the connecting pipe at the position of said lower section and which is provided at a distal end with a nozzle, wherein the pipe system is provided with actuators for controlling a position of the nozzle inside said volume. 2. Installation according to claim 1, wherein the central throughfeed element is height-adjustable relative to the frame. 3. Installation according to the foregoing claim, wherein the central throughfeed element is a hollow post with a slot which extends in the longitudinal direction of the post over substantially its whole operating length, this slot being dimensioned such that the connecting pipe can extend through the slot from inside the hollow post to outside the hollow post. 4. Installation according to the foregoing claim, wherein the frame has a guide mechanism for the connecting pipe so that the connecting pipe protrudes through the slot from inside to outside the post at the position of the frame, irrespective of the height position of the throughfeed element relative to the frame. 5. Installation according to any one of the foregoing claims, wherein the frame comprises a drive mechanism for moving the central throughfeed element upward and downward. 6. Installation according to the foregoing claim, wherein the central throughfeed element is provided with a gear rack and wherein the frame is provided with a gear coupled to a motor, which gear engages on the gear rack. 7. Installation according to any one of the foregoing claims, wherein the pipe system extends substantially lying. 8. Installation according to any one of the foregoing claims, wherein the pipe system comprises at least a first and second pipe segment, wherein the first pipe segment is at a proximal end connected pivotally to the connecting pipe and at a distal end connected pivotally to a proximal part of the second pipe segment, wherein the second pipe segment has said nozzle at a distal end. 9. Installation according to the foregoing claim, wherein the frame has segments corresponding with the pipe segments for holding and controlling the pipe segments. 10. Installation according to any one of the foregoing claims, operatively connected to an engine room with an air displacing mechanism which is provided to generate an air flow through the connecting pipe and the pipe system for the purpose of conveying the bulk good via the air flow. 11. Installation according to any one of the foregoing claims, wherein cover elements for covering the opening in the hold are connected to the frame. 12. Installation according to the foregoing claims, wherein the cover elements are at least partially movable relative to the frame between a folded position and a functional position. 13. Installation according to any one of the claims 11-12, wherein one of the cover elements and the frame comprises a ventilation channel for ventilating the volume, wherein the ventilation channel comprises a dust filter. 14. Installation according to any one of the foregoing claims, wherein the support legs are provided at their distal ends with electromagnets. 15. Installation according to any one of the foregoing claims, wherein the installation is a displaceable installation. 16. Installation according to any one of the foregoing claims, wherein the bulk good is a powder. 17. Method for unloading a bulk good from a hold of a vessel, wherein the method comprises of: opening a hold at the position of an upper side; placing an installation according to any one of the foregoing claims; conveying the bulk good from the hold by means of the installation. 18. Method according to the foregoing claim, wherein the placing comprises of lifting the installation, passing the pipe system through the opening in the hold, and placing the support legs on edges of the opening in the hold. 19. Method according to the foregoing claim, further comprising of connecting the connecting pipe to an engine room with an air displacing mechanism. 20. Method according to the foregoing claim, wherein the conveying comprises of adjusting the height of the throughfeed element in order to place the nozzle at a predetermined height relative to an upper surface of the bulk good, and moving the nozzle reciprocally by moving the pipe system. |
The invention relates to an unloading installation for powders.
When powders are transported by road, this is typically done in a tanker. This is a truck on which a typically substantially cylindrical tank is mounted. Built into the underside of such a tank are systems for fluidizing the powder such that the powder can be pneumatically conveyed into and out of the tank. Pneumatic conveying means that the propelling force with which the powder is conveyed is a gas flow or air flow. It is here in the first instance less relevant whether the gas flow or air flow is realized by suction, underpressure or vacuum, or by blowing or overpressure.
Similar transport means have been developed for ships. More specifically, ships are provided with tanks or silos in which mechanisms are provided at the bottom for fluidizing and pneumatically conveying the powders. A ship typically has a plurality of individual tanks or silos, each having a predetermined volume. The advantage of such a ship is that powders can be transported in reliable manner. Drawbacks are that such a ship is expensive due to its complex construction. The utility is also limited because the tanks are provided fixedly in the vessel. The tanks are also difficult to clean.
It is an object of the invention to improve an unloading installation for transporting powders.
The invention provides for this purpose an installation for unloading a bulk good from a vessel with a hold which delimits a volume in which the bulk good can be held, wherein the installation comprises a frame with support legs for placing the installation on edges of an opening at the position of an upper side of the hold, wherein the installation further comprises a central throughfeed element which extends at least downward from the frame in order to be carried through the opening and into the frame, wherein the throughfeed element is preferably height- adjustable relative to the frame, wherein the installation further comprises a mechanism for pneumatic conveying of the bulk good, wherein the mechanism comprises a connecting pipe which extends through the central throughfeed element and up to a lower section of the central throughfeed element and comprises a pipe system which is connected to the connecting pipe at the position of said lower section and which is provided at a distal end with a nozzle, wherein the pipe system is provided with actuators for controlling a position of the nozzle inside said volume.
The invention is based on the insight that pneumatic conveying of powders can also be realized via the upper side of the volume. A mechanism for fluidizing the powder at the bottom of the volume can hereby be dispensed with. Existing tanks and silos have a mechanism on the underside for fluidizing and pneumatic conveying.
The invention provides an installation which can be placed with legs over an opening in the hold, and wherein the installation has a nozzle which can be moved inside the volume of the hold. The installation has for this purpose a frame with an upright throughfeed which is provided at the bottom with a pipe system. The nozzle will hereby function in the manner of a vacuum cleaner, whereby powder stored in the hold can be sucked up and pneumatically conveyed from the hold in simple manner. The other way around, filling of the hold is also considerably simpler because the hold can be filled via the nozzle, which can be controlled within the volume. The powder can thereby be spread out over the whole surface area of the hold so that formation of dust and piling up of the powder can be avoided.
Because the hold does not comprise a mechanism at the bottom for fluidizing and conveying the powder, the hold can be made flat at the bottom. This appreciably increases the possible applications of the vessel and also allows other types of good to be transported. In other words, the vessel becomes multifunctional. This has been found to have great advantages in practice. This is because powder vessels are typically employed to carry powders from location A to location B. The powder is unloaded and typically also processed at location B. In most cases no new or other powders that require transportation back to location A are made at location B. In practice a powder ship will therefore travel from location B back to location A empty, and be filled again at location A. This is not very efficient, because the ship is only filled for half of the distance travelled. With the vessel according to the invention it becomes possible to transport other goods, for instance pallets or containers or a coarser bulk good such as coal, between location B and location A, this appreciably increasing the cost-efficiency of the vessel. Tests have also shown that cleaning of a hold of a vessel according to invention is significantly simpler than cleaning a silo or tank from a prior art vessel. Building a vessel with an open hold and providing a mechanism is also significantly simpler and cheaper than building a vessel with one or more silos and/or pressure tanks.
The installation is preferably a displaceable installation. More specifically, the installation can be placed on almost any ship with a hold. The support legs are located on the edges of the opening, while the throughfeed element extends into the hold. Provided on the underside of the throughfeed opening is the pipe system with nozzle so that powder can be conveyed from inside to outside the hold via the installation.
The central throughfeed element is preferably a hollow post with a slot which extends in the longitudinal direction of the post over substantially its whole operating length, this slot being dimensioned such that the connecting pipe can extend through the slot from inside the hollow post to outside the hollow post. The slot allows for considerably easier handling of the connecting pipe. More specifically, the connecting pipe will be able to lie on an upper surface or roof of the hold, irrespective of how deep into the hold the throughfeed element extends. The frame further preferably has a guide mechanism for the connecting pipe so that the connecting pipe protrudes through the slot from inside to outside the post at the position of the frame, irrespective of the height position of the throughfeed element relative to the frame.
The frame preferably comprises a drive mechanism for moving the central throughfeed element upward and downward. The central throughfeed element is further preferably provided with a gear rack, wherein the frame is provided with a gear coupled to a motor, which gear engages on the gear rack. The skilled person will appreciate that alternative options can be provided for moving a throughfeed element upward and downward.
The pipe system preferably extends substantially lying. The height of the pipe system can be controlled by adjusting the height of the throughfeed element.
The pipe system preferably comprises at least a first and second pipe segment, wherein the first pipe segment is at a proximal end connected pivotally to the connecting pipe and at a distal end connected pivotally to a proximal part of the second pipe segment, wherein the second pipe segment has said nozzle at a distal end. The frame further preferably has segments corresponding with the pipe segments for holding and controlling the pipe segments. In this way the nozzle can be held at an optimal position relative to the powder surface and be moved to facilitate conveying of the powder in simple manner.
The installation is preferably operatively connected to an engine room with an air displacing mechanism which is provided to generate an air flow through the connecting pipe and the pipe system for the purpose of conveying the bulk good via the air flow.
Cover elements for covering the opening in the hold are preferably connected to the frame. The cover elements are preferably at least partially movable relative to the frame between a folded position and a functional position. One of the cover elements and the frame preferably comprises a ventilation channel for ventilating the volume, wherein the ventilation channel comprises a dust filter. The cover elements enable use of the installation when it is raining. It will be apparent that when the upper side of the hold is opened in order to place the installation, rain may fall via the opening into the hold. This is not desirable, at least not for the entire duration of unloading. The opening is therefore preferably covered. In order to still allow a certain ventilation of the hold, this in order to avoid underpressure and/or overpressure in the hold, ventilation channels are placed. Dust can be kept out of the surrounding area by providing filters in the ventilation channels.
The support legs are preferably provided at their distal ends with electromagnets. The frame can be firmly connected to the edges of the opening of the hold via the electromagnets.
The bulk good is preferably a powder.
The invention further relates to a method for unloading a bulk good from a hold of a vessel, wherein the method comprises of: opening a hold at the position of an upper side; placing an installation according to any one of the foregoing claims; conveying the bulk good from the hold by means of the installation.
The placing preferably comprises of lifting the installation, passing the pipe system through the opening in the hold, and placing the support legs on edges of the opening in the hold.
The method preferably further comprises of connecting the connecting pipe to an engine room with the air displacing mechanism.
The conveying preferably comprises of adjusting the height of the throughfeed element in order to place the nozzle at a predetermined height relative to an upper surface of the bulk good, and moving the nozzle reciprocally by moving the pipe system.
The invention will now be further described on the basis of exemplary embodiments shown in the drawing.
In the drawing: figure 1 shows a perspective view of a vessel which can be unloaded with a device and according to the method of the invention; figure 2 shows a perspective view of a device according to an embodiment placed on a vessel; and figure 3 shows a top view of a device according to a further embodiment placed on a vessel.
The same or similar elements are designated in the drawings with the same reference numerals.
Vessel 1 is also referred to as a ship, and has at least one hold 2. Each hold 2 is formed by a bottom of the ship and upright walls. The bottom and upright walls define a volume. This volume can be filled with goods, for instance bulk goods such as sand, coal, cement, ore or other goods. Break bulk goods can alternatively also be placed in hold 2. Break bulk goods are typically provided on pallets or in containers. These pallets and/or containers can be placed in hold 2 and can even be stacked so as to extend at least partially above the walls of hold 2. These options make a ship 1 widely applicable, thus enabling a high transport efficiency to be achieved. In order to further increase the transport efficiency partitions which divide hold 2 into a plurality of segments are often placed in the hold, as shown in figure 1. In figure 1 one each segment is designated with a reference numeral 2. The volumes of different segments can be filled with different types of good.
Traditionally built for transporting powders are powder ships. These ships have tanks or silos in which the powder can be stored built fixedly into the hold. These silos have means at the bottom for fluidizing the powder in order to convey the powder. In the context of this description powder is defined as a dry bulk material containing a large number of extremely small particles. In the context of this invention the powder has flow properties, and a powder can therefore be fluidized. Powders can be displaced via pneumatic conveying. A pneumatic conveying system displaces a powder by creating an air flow through a pipe, which air flow entrains the powder through the pipe.
Pneumatic displacing of powders by means of an air flow can cause dust to form. Dust formation in combination with pressure as a result of the air flow should preferably be filtered. This is to prevent excessive amounts of dust ending up in the ambient air. There are European standards regarding excessive dust in the ambient air, namely a maximum of 5 mg/m 3 .
Using hatches 3 to close the loading space 2 has the advantage that access to the loading space can be provided for a grab of for instance a transfer crane by sliding the hatches 3. For loading and unloading of powders the hatches 3 are provided to be preferably substantially watertight and substantially dust-tight.
Figure 2 is a schematic drawing in cross-sectional and perspective view of a hold 2 of a vessel. The hold 2 is provided at the top with hatches 3a and 3b, which are partially open in figure 2. Partially opening the hatches 3 creates an elongate opening 6 in the upper side of hold 2, through which access from outside is provided.
Figure 2 further shows a device comprising a frame 4 with a plurality of support legs 5. Support legs 5 are formed to be positioned on edges of the opening 6 and so hold a central zone of the device above opening 6. Four support legs 5 are shown in the figure. The skilled person will appreciate that fewer or more support legs 5 can also be provided to hold a central zone of the device above opening 6. In figure 2 the legs extend substantially lying. The legs can alternatively also extend at a downward angle, departing from the frame. The legs can also take a different form, for instance the form of a bar which supports against an upper surface over a distance. Two legs can thus for instance be provided, at least one leg of which has a T-shaped end for placing the installation over the opening in a stable manner.
A throughfeed element 7 is formed centrally on the frame. Centrally must be understood to mean in a central zone of the frame. Centrally thereby does not require throughfeed element 7 to be formed in the centre or in the centre of gravity of the frame. The only thing required by the word centrally is that throughfeed element 7 not be formed on a corner and preferably not be formed on an edge either.
Throughfeed element 7 is shown in a preferred embodiment, wherein throughfeed element 7 can be moved upward and downward relative to the frame. This is advantageous because the complexity of the movement of nozzle 11 (further discussed hereinbelow) is minimal during conveying of powders. In an embodiment which is not shown the central throughfeed element 7 is however connected fixedly to the frame, whereby it does not necessarily extend upward from the frame. In such an embodiment the pipe system 10 (further discussed hereinbelow) will be more complex so as not to allow only a horizontal movement of nozzle 11 over substantially the whole powder surface, but to also be able to realize a vertical movement of the nozzle. The primary object of the device according to the invention is to unload a bulk good from a hold of a ship. More specifically, the primary object of the invention is to provide a mechanism whereby powder can be conveyed from hold 2. In order to convey powder from hold 2 the principle of a vacuum cleaner can be used. A nozzle 11 is here moved along a surface of the powder in order to suck up the powder by means of an air flow and so convey it. The device comprises for this purpose a connecting pipe 8 which is provided for connection to an engine room with air displacing means. The connecting pipe has a length which is able to bridge a distance between an externally located engine room and the frame. The connecting pipe is for instance a flexible pipe with a diameter lying between 8 cm and 50 cm and with a length of at least 10 metres, preferably at least 15 metres, more preferably at least 20 metres. The connecting pipe has an open end at a distance from the frame, whereby the connecting pipe can be connected to the engine room, and has an end at the position of a lower segment 9 of throughfeed element 7.
Connected to lower segment 9 is a pipe system 10. Pipe system 10 is operatively connected to connecting pipe 8 at the position of lower segment 9 such that an air flow, liquid flow, semiliquid flow or other powder flow is able to flow from pipe system 10 to connecting pipe 8 and/or vice versa. Pipe system 10 has at least two segments. Figure 2 shows an embodiment wherein pipe system 10 has a first segment 17 and has a second segment 18. The first segment 17 extends between lower section 9 and second segment 18. At the position of lower section 9 the first segment 17 is preferably rotatable about an upright axis. First segment 17 can hereby extend over the surface of the powder in different directions. A rotary coupling is preferably provided between first segment 17 and connecting pipe 8 at the position of lower section 9, so that rotation of first segment 17 does not cause torsion of connecting pipe 8. The rotation of first segment 17 is preferably controlled by at least one actuator which is provided between first segment 17 and frame 4. First segment 17 can have a frame part which forms part of the frame and which supports first segment 17. This frame part can then be connected movably to frame 4 via actuators.
In the shown embodiment the second segment 18 extends between first segment 17 and a nozzle 11. Second segment 18 is preferably connected rotatably to first segment 17, such that second segment 18 is able to rotate relative to first segment 17 about an upright axis. In this configuration, particularly when second segment 18 has a length which is roughly the same as the length of first segment 17, a combination of rotations of first segment 17 relative to frame 4 and of second segment 18 relative to first segment 17 enables almost any position in a lying plane in hold 2 to be reached with nozzle 11. The second segment can also be provided with a frame part which is connected rotatably to the frame part of the first segment so as to be driven via actuators.
In the shown embodiment pipe system 10 is formed with a SCARA configuration, wherein the nozzle is movable in a substantially horizontal plane. The height of the nozzle can be controlled by moving throughfeed element 7 upward and downward. This allows a simple construction of the device. This is because the rotations of first segment 17 and second segment 18 need only be controlled in one direction, i.e. about one rotation axis. This is advantageous both for the mechanical construction and for actuation of the movement.
Throughfeed element 7 takes the form of a hollow post which in an upward orientation is connected substantially centrally to frame 4. The frame is provided here with a motor 15 with a gear, and the post is provided with a gear rack 16. By having the gear engage in the gear rack and operating the engine the height of the post relative to the frame can be changed. The height of lower segment 9, and the associated height of the nozzle 11 in hold 2, in particular is controlled via motor 15. The combination of controlling the height of nozzle 11 via motor 15 and controlling the position in the horizontal plane of the nozzle via the rotations of first segment 17 and second segment 18 about an upright axis enables the nozzle to reach almost all positions within the entire volume of hold 2.
The skilled person will appreciate that in an alternative embodiment pipe system 10 can also be formed with telescopic elements, and can be provided to rotate about axes which are positioned at an angle or are lying, in order to enable almost all positions inside the entire volume of hold 2 to be reached with the nozzle.
Central throughfeed element 7, taking the form of a post, is preferably hollow. The cavity is designated with reference numeral 13. Connecting pipe 8 can extend via the cavity up to the lower segment 9. The post preferably has a slot 14. The slot extends over at least the whole operating length of the post and has a width greater than the diameter of connecting pipe 8. Whole operating length is understood to mean the part of the post which can come to lie at the position of frame 4 during normal operation of the device. The primary object of slot 14 is to allow connecting pipe 8 to exit from the post at the position of frame 4. It is particularly when the post protrudes high above frame 4, as shown in figure 2, that this will prevent connecting pipe 8 from exiting from the post all the way at the top. Connecting pipe 8 can exit from the post at the position of frame 4 in any position of the post relative to frame 4, so that connecting pipe 8 can be handled easily. This facilitates use of the device and increases safety.
The device can be applied irrespective of whether hatches 3 open in the longitudinal direction of the ship or the transverse direction of the ship. Different sizes of hold can also be unloaded. The skilled person will appreciate that the dimensioning of pipe system 10 and central throughfeed element 7 are relevant hereto.
Figure 3 shows a top view and shows a further aspect of the invention. Shown on the righthand side of the figure is connecting pipe 8, which is connected at a distal end to an external engine room. Shown on the left-hand side with broken lines are first pipe segment 17 and second pipe segment 18. These are shown with broken lines because they are situated in hold 2, below the upper surface thereof. Figure 3 shows the frame 4 and the support legs 5. The support legs are provided at distal ends with magnets 24, preferably electromagnets. Suction cups can alternatively be provided to connect support legs 5 releasably to the upper surface of the hold. The figure shows that each leg 5 is provided with a magnet 24. Alternatively, only one of or a selection of the legs 5 can be provided with a magnet 24. An electromagnet has the advantage that magnetic attraction and resulting connection of the legs to the surface can be controlled.
Figure 3 further shows that frame 4 is provided with additional elements for covering the opening which results between hatches 3a and 3b to maximum extent. Rain is hereby unable to fall into the hold when the installation is in place. More specifically, one or more filters 23 are provided bordering on the location where the central throughfeed element 7 is connected to the frame. Filters 23 are provided in an air passage opening and filter incoming and outgoing air, typically by mechanically obstructing particles of a predetermined particle size. The predetermined particle size is determined by the type and the properties of the filter material used to make the filter. By providing an air passage opening with a filter the space can be ventilated, underpressure and overpressure can be avoided and dust, coming from the powder, to the surrounding area can be minimized.
At least two cover elements 20a and 20b are further preferably connected to frame 4. Cover elements 20 are each provided on one side of the frame in order to cover the opening on that side. Cover elements 20 preferably connected movably or removably to the frame. This is illustrated in that cover element 20a is in folded-down position in figure 3 and thereby wholly covers the opening between the hatches 3a and 3b on that side of frame 4. Cover element 20b is shown in partially upward position in figure 3, and arrow 21 indicates the folding down of the cover element. In figure 3 hinges 22 are provided between each cover element 20 and the frame. It will be apparent that a snap mechanism or tilting mechanism or other mechanism can be provided to connect the cover elements to the frame.
Use of the device as described above is simple and as follows. When a vessel arrives at a location where the vessel can be unloaded, hatch 3 is opened at least partially. A device as described above is moved toward the vessel and is carried with its pipe system and at least the lower section of the central throughfeed element into hold 2 via the opening. The device is then placed with its support legs on edges of the opening. These legs can be locked, for instance by switching the electromagnet. After placing, the cover elements 20 are placed to cover opening 6. The connecting pipe is then connected via an engine room. By driving an air flow in the connecting pipe the nozzle 11 can suck up powder in the hold in the manner of a vacuum cleaner. The pipe system then preferably moves systematically over the surface of the bulk good in the hold. The throughfeed element will also systematically drop down in accordance with the amount of material which has been unloaded from the hold in order to maintain an optimal position of nozzle 11 relative to the surface. When the hold is empty, the electromagnets can be switched off and the device lifted off the hold. In this way no requirements are imposed on the vessel for the purpose of unloading the powder. Powder can be unloaded dry and in simple manner.
The skilled person will appreciate on the basis of the above description that the invention can be embodied in different ways and on the basis of different principles. The invention is not limited to the above described embodiments. The above described embodiments and the figures are purely illustrative and serve only to increase understanding of the invention. The invention will not therefore be limited to the embodiments described herein, but is defined in the claims.