BULK MATERIAL STORAGE WITH UNLOADING DEVICE HAVING A MOVABLE WALL AND METHOD FOR UNLOADING SUCH STORAGE

Abstract: An unloading device for bulk material in a storage space, comprising a conveyor means (5) to discharge the bulk material in the longitudinal direction of said storage space (1) wherein said conveyor means is, at least during the end phase of unloading, at a low level within the storage space, and a displacable wall part (7) and driving means for displacing said wall part such as by supplying a pressure fluid to a chamber adjacent said wall part, such that by displacing said wall part bulk material moves towards said conveyor, such as in a storage space wherein a boundary is present preventing the flow of bulk material aside said boundary towards the conveyor.

Description: BULK MATERIAL STORAGE WITH UNLOADING DEVICE HAVING A MOVABLE WALL AND METHOD FOR UNLOADING SUCH STORAGE The invention is concerned with a bulk material storage with unloading device with displacing wall part and method for unloading such storage. From EP-A-0523126 a ship hold is known with an automatic unloading device, comprising a horizontal scraper conveyor, movable between a high and a low position, and on both sides thereof flexible walls located against the hold wall and movable by compressed air, said walls being designed to carry bulk material to the conveyor that is not carried thereto by gravity. The conveyor is designed such that during the end phase of unloading the conveyor slides the bulk material forwardly over the flat ship bottom, to which a side edge of the flexible walls is also connected. The flexible walls are mounted to the hold wall and to four inflatable sections located between said walls and the hold wall such that in an end position they provide an inclined upwardly and outwardly from the conveyor extening flat panel making an angle with the horizontal larger than the natural slide angle of the bulk material. These flexible walls are mainly designed for exclusively sideways displacement of the bulk material. However, one specific embodiment is described, wherein prior to the end phase of unloading, the bulk material immediately aside the conveyor is raised to make sure that it slides downward to the conveyor. In that case in a first step the outward inflatable section 14a is slighly inflated, whereafter in a second step the inner inflatable section 14d is partly inflated and there- after the outward inflatable section is further inflated while simultaneously the inner inflatable section is slightly emptied. The second step can be repeated several times. During the end phase of unloading first the mid inflatable sections 14b and 14c are alternatingly inflated and emptied and finally the flexible walls provide the inclined upwardly and outwardly from the conveyor extening flat panel. Thus, EP-A-0523126 does not disclose raising of bulk material during the end phase of unloading. From GB-B-1241162 a ship hold is known with an automatic unloading device, comprising a horizontal conveyor provided in a central recess in a furthermore flat hold bottom and on both sides thereof flexible walls located against the hold wall and movable away therefrom by compressed air, which are designed to carry the bulk material to the conveyor that is not carried thereto by gravity. The flexible walls provide a wall part of a single inflatable chamber mounted to the hold bottom adjacent the central recess and to the hold side wall at a higher level. This document does not teach, that the bulk material is raised by the flexible walls. In their end position the flexible walls provide the circumference of a circle segment, of which the centre of curvature is located far outside the hold. In one aspect the object of the invention is a multi purpose system and method of above type as alternative to the prior art. In an alternative aspect the object is maximization of the space use of the storage for bulk material. In another alternative aspect the object is the possibility of provision in an already existing storage. In a still further alternative the object is increased protection against wear. In another alternative aspect the object is a reliable displacement behaviour of the displacable wall. In still another alternative aspect the object is a more favourite loading of the displacable wall. In a further alternative aspect the object is completely automatic unloading of the hold. Alternatively, the object is combination of two or more alternative aspects of the invention. Therefor, the invention is characterised by the enclosed one or more independent claims. Dependent claims relate to further developments of the invention. Although the invention is here particularly described in relation with a ship hold, it must be obvious that the invention is applicable to many other fields. Examples of other fields of application are the cargo hold of a land vehicle, such as a lorry or train wagon, or a stationary storage site. According to an embodiment of the invention care is taken such that the discplacable wall part carries the bulk material to a higher level during at least the end phase of unloading, preferably from a level below a boundary edge in the central part of the storage or adjacent the conveyor present therein, to at least substantially the same level or thereabove. In that way it is possible to automatically unload the storage completely without the need for special structural measure- ments to the storage and/or the conveyor, such as in case of GB-B-1241162 or EP-A-0523126, repsectively. According to a preferred embodiment this carrying to a higher level is made possible in that the end of the displacable wall part adjacent the conveyor at least during the end phase of unloading is present at a higher level. Further advantages, alternative objects and alternative apects of the invention will be clear from the description of a presently, non-limiting, best mode for carrying out the invention, as shown in the drawings, which show in: Fig. 1 schematically in cross section a storage according to the invention, during two different unloading steps; Fig. 2 a view similar to fig. 1 of the storage during two other unloading steps; and Fig. 3 the storage of fig. 1 in top view. The storage 1 in this embodiment is the hold of a vessel 20 that floats in the water 21. A vessel for inland-navigation is shown, that can be designed as push or tow barge or as ship. However, the vessel can also be a sea ship or a so called coaster. But the invention is particularly applicable to the inland-navigation, since in that area there are tight restrictions to the maximum obtainable hold volume by a.o. regulations (a.o. safety and environment), ship channel depth, water levels and maximum passage height below bridges or else. The hold 1 is typically delimited by fixed, at least substan- tially vertical, side walls 2, 3 and a fixed, at least substantially flat, floor 4 therebetween. Walls 2, 3 and floor 4 are made of sheet material, preferably metal such as steel. They can be part of a double wall or bottom, as is typical. Details, such as cable gutters, cable shafts or other typical appliances are not shown. In the central part of the hold 1 a longitudinally extending conveyor 5 is provided therebeneath, the conveying surface of which is at some distance above the floor 4. The convey- or 5 can be a belt type, screw type or chain type, or any other convenient conveyor type. The conveyor has a typical structure and is therefor not further examplified. Above the conveying surface of the conveyor 5 there is provided a merely schematically illustrated dispensing member 16. This can be a simple stationair protection cage 16, known as such, through which bulk material always passes. In an alternative this can be a bulk material passing structure that can be controllably closable at its top and/or sides, such that flow of bulk material towards the conveyor 5 is controlled. In that case this member 16 can have controlled, e.g. with slides, closable bulk material passage openings on top and/or aside. The conveyor 5 feeds bulk material to a lifting conveyor 6 (see fig. 3) provided at a longitudinal end, which brings the bulk material to a desired level, e.g. tranfers it onto a discharge conveyor (not shown) above the hold 1 and extending to the shore. The displacable wall part is in this embodiment provided by a flexible membrane 7 extening lengthwise of the hold 1 and of preferably wear resistant and pull tight material, e.g. of a (natural) rubber or plastic, such as PVC or polyurethane, possibly reinforced with fibres, wherein said membrane 7 preferably has only a small elastic elongation at pulling forces, e.g. 10% at the most. The membrane 7 is with its upper edge 12 at least substantially indisplacable mounted to the side wall 2 or 3, and with its lower edge 14 at least substantially indisplacable mounted to the upper edge of a bulkhead 22 extending at a distance adjacent the conveyor 5 upwards from the floor 4. This bulkhead 22 provides a barrier to a flow towards the conveyor of bulk material adjacent the bulkhead 22. A slide gutter 26 connects to the upper side of the bulkhead 22 and extends sideways and downwards towards the conveyor 5. Between the membrane 7 and fixed boundaries 2, 3, 4 of the hold 1 there is a inflatable chamber 23, delimited by a fluid tight membrane 11 that is, according to the cross section of fig. 1 a closed loop extending longitudinally of the hold 1 such that it is tube, hose or sausage shaped. While in this embodiment the inflatable chamber 23 is made from a single section, also an embodiment is possible wherein the inflatable chamber comprises several, such as two or three of more sections, e.g. provided by as many separate tubes 11. If divided into several sections, it is possible to inflate the inflatable chamber in a controlled way by separately inflating and/or emptying one or more sections, for which control means can be present. However, then also an embodiment is possible, wherein at least substantially simultaneously fluid is fed to the several sections, such that a behaviour is provided that is at least substantially comparable with that of a single inflatable chamber 23. The inflatable chamber 23 is connected to inflating means, such as a compressed gas (air) source, such that inflating is possible. It will be obvious to the skilled person, how the inflating means should be designed with valves or else to controllably inflate and empty the inflatable chamber 23. At a high and a lower level, here at the longitudinal edge 12 and 14, respectively, of the membrane 7, the boundary of the inflatable chamber 23, provided by the membrane 11, is at least substantially indisplacable mounted to the surrounding structure. In this way the deformation behaviour of the inflatable chamber is positively influenced. Also at the location indicated with 13 the inflatable chamber is at least substantially indisplacable mounted to the surrounding structure. Unloading the hold 1 proceeds as follows: While the membrane 7 is pressed against the fixed hold boundary 2, 3, 4 and the hold 1 is completely filled with bulk material, the conveyor 5 is engaged such that the bulk material below the dispensing member 16 is fed in longitudinal direction towards the lifting conveyor 6, which takes the bulk material above the hold. With gravity aid the member 16 continuously allows enough bulk material to the conveyor 5 such that it almost continuously discharges bulk material. After some time the situation is obtained as illustrated at the left-hand side of the drawing of fig. 1, wherein the bulk material provides a natural slope 15, and therefor no longer automatically flows towards the conveyor by gravity action. At some time during the period that the automatic flow of bluk material towards the conveyor starts to decrease untill zero in that the slope 15 starts to form ("zero" means the time at which the slope shape 15 is obtained), one begins to move the membrane 7 away from the fixed hold boundary 2, 3, 4. Therefor compressed fluid is fed to the inflatable chamber 23, such that the membrane 7 is loaded by the membrane 11. This pressing away starts close to the upper edge 12 of the membrane 7 and results in that the bulk material at the top of slope 15 is pressed aside, such that it flows downwards towards the conveyor 5 along the slope 15 (viz. arrow 17 in fig. 1). This is a continuing process, wherein the height of the slope 15 gradually deminishes while the membrane 7 is more and more pressed away, first merely from the relevant side wall 2, 3, at a later moment also from the floor 4. Thus, the shifting point 24 where membrane 7 disconnects from the hold boundary 2, 3, 4 gradually moves from the edge 12 to the edge 14. It is surprisingly found out that the desired, optimised, displacement of the bulk material is obtained with the membrane 7 without requiring that the inflatable chamber 23 is sectionwise exposed to compressed air, as is known from EP-A- 0523126. According to the present invention the loading of the membranes 7, 11 is therefor more favourite, yielding a more favourite service life or, at equal service life, a material savings. Indeed, GB-B-1241126 teaches that the inflatable chamber is a single part, viewed in cross section of the hold, however it does not disclose the moment in time at which the bulk material in the hold is brought into movement and also not the way in which the inflatable chamber is shaped during inflation, while also no disclosure is given of a material layer between the inflatable chamber and the bulk material, such as the membrane 7 according to the present invention, such that when applying the teachings of GB-B-1241162, the effects of the present invention are not obtained. The single inflatable chamber 23 also offers the possibility of extreme displacement of the membrane 7 (viz. the right-hand side of the drawing of fig. 2). The pressure head in the inflatable chamber 23 does not have to rise above 1 bar, and it is found out that a pressure head of about 0.2 bar can be convenient. The length of the inflatable chamber 23 depends on the dimensions of the hold 1 and can be 13.5 m. Thus, after some time a situation is obtained as shown in the drawing to the right-hand side of fg. 1 or the left-hand side of fig. 2. The membrane 7 now also provides that bulk material present below the level of the upper egde of the bulkhead 22 arrives at least at the same level and preferably thereabove, such that also said bulk material can arrive at the conveyor 5. By continuing unloading finally the situation is abtained shown to the right-hand side in the drawing of fig. 2. Due to this displacement of the membrane 7, at least during this end phase of unloading the bulk material still within the hold 1 and aside the conveyor 5 is moved upward to arrive at the slide gutter 26 to slide thereover and onto the conveyor 5 due to gravity action. The hold 1 is automatically and completely unloaded, despite the presence of the bulkhead 22 in the central area of the hold 1, which bulkhead 22 provides a boundary edge at a substantial distance of e.g. at least 10 cm above the floor 4. As the drawing shows, it is preferred that the membrane 7 arrives at an end position at the end of unloading, wherein at least a part 25 at a distance to its edges is at least substantially at the level of the edge 12 or thereabove and/or at least substantially vertically above the edge 14 or there beyond. This is e.g. possible if the edge 14 is at a distance above the floor 4 and in rest the membrane is at least over substantially its complete surface supported by the bulkhead 22, the floor 4 and the side wall 2 or 3. It is appreciated that the membrane 7 experiences an important change of position at its edges 12, 14. If with its edges 12, 14 fixedly clamped, the membrane will deform i por- tantly due to bending. In an attempt to limit said deformation, it is preferred to design the clamping means such that they can pivot. Fig. 3 shows that the membrane 7 does not occupy the complete length of the hold 1, and that a part of the hold is occupied by a next membrane 8 that can be operated independent of the membrane 7, and therebehind there is an inflatable chamber independent from inflatable chamber 23. The conveyor 5 is common to all membranes 7, 8. Therefor the parts front, back, left and right of the hold 1 can be unloaded mutually independently, favourising the balance of the hold 1. It is obvious how the inflatable chambers are sealed at the longitudinal ends . Further alternatives also belong to the invention. E.g. wherein the edge 14 is mounted such that it can move upward. E.g. the edge 14 is initially located at the floor 4 while during the end phase of unloading it moves upward along the bulkhead 22 to arrive at the end position shown to the right in the drawing of fig. 2. According to another alternative the part of the membrane 7 extending along the bulkhead in fig. 1 can be replaced by a bending rigid sheet (shown in phantom as 28 in fig. 2) the longitudinal edge 14 of which is pivotably mounted to the upper edge of the bulkhead 22 while its lower edge (shown in phantom as 27 in fig. 2) is mounted to the corresponding longitudinal edge of membrane 7. In an alternative to this the membrane 7 can be mounted to the bulkhead 22 while the free longitudinal edge of said sheet 28 rests freely onto the membrane 7. In both embodiments the membrane 7 provi- des, at least during the end phase of unloading, for the upward movement of a pivoting sheet aside the conveyor, yielding complete unloading. While the drawing shows that the conveyor is completely above the floor 4, the invention also covers and embodiment wherein the conveyor is at least partly lowered into the floor 4. The invention also covers an embodiment wherein the conveyor means is a slide sheet or gutter, possibly inclined. The invention also covers embodiments based on one or more separate details, or a functional equivalent therefor, of the embodiments as described above and shown in the drawing. Thus, the invention is concerned with, a.o., an unloading device for bulk material in a storage space, comprising a conveyor means to discharge the bulk material in the longi- tudinal direction of the storage space wherein said conveyor means, at least during the end phase of unloading is at a low level within the storage space, and a dispalcable wall part and driving means to displace said wall part, such as by supplying a pressure fluid to a chamber adjacent said wall part, such that by displacing said wall part bulk material moves towards said conveyor. Particularly the invention con- cenrs such an unloading device applied to a storage space having a boundary preventing the flow of bulk material aside said boundary towards the conveyor. The invention is also concerned with a method for unloading a storage space filled with bulk material, wherein at least during the end phase of unloading a wall part is displaced to provide that bulk material moves toward a conveyor, wherein said wall part prefera- bly initially rests against a boundary of said storage space. According to a further alternative aspect of the invention it is possible to make the conveyor means easy accessible for e.g. work to be carried out thereon, such as maintenance or repair. According to a further development of the inventi- on, the requirement to remove the bulk material from the storage space in downward direction is eliminated.

Claims: CLAIMS 1. Storage (1) comprising two fixed walls and a bottom and provided with a displacable wall part, which wall part e.g. has a flexible part on the one hand delimiting the storage space and on the other hand delimiting a chamber with variable volume, wherein said displacable wall part is cargo feeding connected to a discharge (5), which discharge extends preferably above the floor of the storage, characterised in that the wall part preferably comprises a single circumferentially closed elongated annular part (11), viewed over the height of the storage. 2. Storage according to claim 1, wherein a number of mutually independent operatable, displacable wall parts is provided in the longitudinal direction of said hold. 3. Storage according to any of hte preceeding claims, wherein said discharge comprises a conveyor extending in the longitudinal direction of said hold. 4. Storage according to claim 3, wherein said conveyor is a belt conveyor. 5. Storage according to any of the preceeding claims, wherein said flexible wall part is mounted to the top side of a fixed wall of said hold and to the boundary of the conveyor. 6. Storage according to claim 5, wherein the mounting is a pivot mounting. 7. Storage according to any of the preceeding claims, being part of a vessel. 8. Storage according to any of the preceeding claims, wherein said chamber is provided with water feed/discharge means .

Inventors: KEIJSERS ALBERTUS MARTIN PETRU, KEIJSERS, ALBERTUS, MARTIN, PETRUS
Applicants: KEIJSERS ALBERTUS MARTIN PETRU, KEIJSERS, ALBERTUS, MARTIN, PETRUS
Application year: 2000
Main classification: B63B27
IPC codes: B63B27, B65D88