MATERIALS TRANSPORTATION AND STORAGE APPARATUS

Abstract: A storage container is provided with a base comprising inclined walls for directing descending material in the container towards a plurality of discharge locations. The inclined walls may define a plurality of hexagonal or circular hoppers. Material may be drawn from the discharge location by vacuum, or may pass through openings at the discharge locations.

Description: MATERIALS TRANSPORTATION AND STORAGE APPARATUS The present invention relates to apparatus for the transportation and storage of materials. In particular, the present invention relates to apparatus for the transportation and storage of bulk solid particulate materials such as grain, pulverised fuel ash (PFA) , plastics, fertilisers, animal feeds, pelletised sewage materials, chemical or pharmaceutical components or products, foodstuffs, or any other particulate materials. The present invention also relates to a base for a storage container. It is presently known to store bulk solid particulate materials in silos on sites where the materials are either awaiting use as a component in the manufacturing of an end product, a by-product of such a manufacturing process, or the product itself. For example, grain is used in the manufacture of spirits such as whisky, PFA is a by-product from the burning of coal in power stations, and animal feed may be stored in silos before being bagged or transported in bulk. The silos in which such materials are stored are generally of one of two different forms. These are: (i) flat-bottomed silos of relatively large diameter; and (ii) silos having a tapering lower base or hopper defining an outlet, such silos typically being relatively tall and of small diameter, and being supported above ground upon a framework. Silos having a tapering base or hopper defining an outlet require a hopper with a wall angle of approximately 60° from the vertical to enable materials of average cohesion to flow from the silo. This limits the diameter of the silo, and results in relatively tall, slender silos which are expensive to manufacture, and require supporting framework, discharge conveyors, loading spouts and the like beneath the outlet of the hopper, further increasing the height of the silo. Flat-bottomed silos are less expensive to construct than the hopper silos, are generally of lower height, having a relatively large diameter, and are disposed with their base adjacent to and supported by the ground. However, the withdrawal of material from such flat-bottomed silos is less straightforward, as the silos require complex material extraction apparatus . Such extraction apparatus is typically a mechanical auger or screw feed discharger mechanism, comprising a helical, rotating auger which transports material stored in the silo to an outlet. However, materials may build-up in areas of the silo which are beyond the reach of the auger, requiring a periodic manual ' excavation of built-up materials, particularly where perishable materials such as grain or foodstuffs are stored in the silo. In an effort to overcome this problem, various forms of mechanical systems have been employed. One system employs multiple augers arrayed around the base of a flat- bottomed silo, discharging to a single or multiple outlets. Alternative systems employ a single auger, including a planetary rotation mechanism to rotate the auger around the base of the silo, or a fixed auger in a rotating silo. However, all of these mechanical discharge systems are expensive to construct, and are susceptible to a high degree of erosive wear and other problems associated with moving parts in a harsh environment. Furthermore, if the system should fail or require maintenance, a manual excavation of material in the silo is required to gain access to the auger before replacement of failed components or maintenance can be carried out. This is time-consuming, and delays the withdrawal of material whilst the necessary work is completed. Alternative materials extraction apparatus comprises a number of gas permeable tiles, forming a sloping base in the flat-bottomed silo. Aeration of the material in the silo allows the material to "flow" towards an outlet of the silo. However, this technique is only suitable for materials which are not cohesive, and is therefore not suitable for extracting, for example, fine materials, damp or fibrous materials . In further alternative systems, it is known to provide a so-called "suck-blow" system for discharging materials, typically from large storage silos or sheds, the holds of ships and the like. Such systems comprise a single static inlet nozzle in the silo or the like, connected to a vacuum vessel via a conduit, with a pressure vessel connected to the vacuum vessel and a discharge tube through which air flows under pressure. However, in such systems, it is difficult to balance the air requirements in the vacuum and the discharge conduits, it is not possible to provide a continuous flow of material, and there remains a need to perform a manual excavation of the storage vessel or the like to remove material which cannot be accessed by the static inlet nozzle. It is amongst the objects of the present invention to obviate or mitigate at least one of the foregoing disadvantages According to a first aspect of the present invention, there is provided apparatus for the transportation of solid particulate material from a material source, the apparatus comprising: a vacuum chamber for receiving material from the material source; a vacuum means for creating a vacuum in the vacuum chamber for drawing material into said vacuum chamber; an intermediate chamber for selective communication with the vacuum chamber for receiving material from the vacuum chamber; and a discharge chamber for selective communication with the intermediate chamber for receiving material from the intermediate chamber and for discharging material therefrom. Thus the present invention may allow material to be continuously withdrawn from the material source, whilst simultaneously continuously discharging material from the discharge chamber. This may be achieved by continuously withdrawing materials into the vacuum chamber, and selectively discharging material from the vacuum chamber into the intermediate chamber, and from the intermediate chamber into the discharge chamber. The intermediate chamber may receive materials from the vacuum chamber, to allow the continuous withdrawal into the vacuum chamber simultaneously with the discharge from the discharge chamber. The solid particulate material may be grain, pulverised fuel ash (PFA) , plastics, fertilisers, animal feeds, pelletised sewage materials, chemical or pharmaceutical components or products, foodstuffs, or any other material . The material source may be a storage vessel, a silo, a ship's hold, a building such as a warehouse, or any other suitable source. Preferably, the apparatus further comprises a conveying means for conveying material discharged from the discharge chamber. The conveying means may comprise a conveying conduit coupled to the discharge chamber and to a compressor, the conduit having at least one outlet distal from the apparatus at a point where the material is to be transported. Thus, the compressor may provide a flow of air in the conduit which travels in a direction towards the outlet of the conduit, to transport the material through the conveying means. Preferably, the apparatus is a self-contained unit located out with the material source. Thus, the apparatus may be serviced and maintained without disrupting the storage of material in the material source, as would be the case, for example, where a mechanical auger is provided for transportation of material from the material source. Furthermore, this may enable the apparatus to be used with a plurality of material sources. Also, in the case of shut-down for maintenance, the apparatus may be replaced with an alternative apparatus, enabling transportation of material from the material source to continue with minimum disruption. Conveniently, in use, the vacuum chamber is disposed uppermost of the vacuum, intermediate and discharge chambers, and the discharge chamber is disposed lowermost. Preferably, the vacuum chamber, the intermediate chamber and the discharge chamber comprise pressure vessels. The vacuum chamber, intermediate chamber and the discharge chamber may be adapted to withstand variations in pressure both above and below atmospheric pressure. Preferably, the vacuum chamber further comprises a material inlet and a material outlet. The material inlet may be coupled to the material source. Conveniently, the material inlet is coupled to the material source via a conduit. The conduit may include a nozzle disposed within the material source. The apparatus may further comprise gas injection means for injecting a gas into the material in the material source, to aerate said material for aiding withdrawal thereof. The gas injection means may comprise a conduit coupled to a gas supply, the gas injection conduit having an outlet disposed in the material source. Alternatively, the apparatus may further comprise a conduit having an inlet open to atmosphere, to allow gas to be supplied to the material in the material source through an outlet, to aerate said material for aiding withdrawal thereof. The outlet may be disposed adjacent to the inlet of the material conduit. Preferably, the vacuum means comprises a vacuum pump coupled to the vacuum chamber via a vacuum conduit . Thus the present invention may allow that, when the vacuum pump is activated, a vacuum or at least a partial vacuum, is created within the vacuum chamber. This in-turn "sucks" material into the vacuum chamber from the material source, via the material conduit nozzle, the material conduit and the inlet of the vacuum chamber. Preferably, the intermediate chamber further comprises a material inlet and a material outlet. Conveniently, the material inlet of the intermediate chamber is coupled to the material outlet of the vacuum chamber. Preferably, the discharge chamber further comprises a material inlet and a material outlet. Conveniently, the material inlet of the discharge chamber is coupled to the material outlet of the intermediate chamber. Preferably, the apparatus further comprises two or more material flow valves. The first material flow valve may be disposed between the outlet of the vacuum chamber and the inlet of the intermediate chamber. The second material flow valve may be disposed between the outlet of the intermediate chamber and the inlet of the discharge chamber. The material flow valves may be actuated between an open and a closed position to selectively allow material to flow between the respective chambers. Preferably, the apparatus further comprises means for equalising the pressure between selected ones of the chambers. Conveniently, the apparatus includes at least two such means for equalising pressure, and may comprise a first means for equalising the pressure between the vacuum chamber and the intermediate chamber, and a second means for equalising the pressure between the intermediate chamber and the discharge chamber. The means for equalising the pressure may comprise a conduit coupled at one end to a selected one of said chambers, and at an opposite end to a selected second one of said chambers, to allow fluid communication between said selected chambers. The means may further comprise a fluid flow valve disposed in the conduit and which may be actuated between an open and a closed position to selectively allow fluid communication between the said chambers. The means may further comprise a filter to prevent the solid particulate material from passing through the conduit . According to a second aspect of the present invention, there is provided a method for the transportation of solid particulate material from a material source, comprising the steps of: withdrawing material from the material source into a first chamber; selectively discharging material from the first chamber into an intermediate chamber; selectively discharging material from the intermediate chamber into a discharge chamber; and discharging material from the discharge chamber. Preferably, the method further comprises the step of creating a vacuum in the first chamber to withdraw the material from the material source. The method may further comprise the step of coupling a material conduit between the material source and the first chamber. Conveniently, the method further comprises the step of conveying material discharged from the discharge chamber to a point where the material is to be discharged. The step of conveying material may comprise providing a discharge conduit having at least one outlet and an inlet which is in communication with the discharge chamber, and creating a flow of gas through the discharge conduit to transport the material. According to a third aspect of the present invention, there is provided apparatus for the transportation of solid particulate material from a material source, the apparatus comprising: a material withdrawing means for withdrawing material from the material source; and at least two material transportation conduits, selectively coupled to the material withdrawing means, and each having an inlet in the material source for transporting material therefrom, wherein said inlets are disposed spaced apart in the material source to selectively withdraw material from at least two spaced locations therein. Conveniently, a plurality of material transportation conduits are provided. The material transportation conduits may be selectively coupled to the means for withdrawing material by providing a valve associated with each material transportation conduit and which valve may be actuated between an open and a closed position. Thus, the present invention may allow material in the material source to be withdrawn from a number of locations, to prevent the build-up of material in locations in the material source which cannot be accessed by a single conduit. Thus the need for a manual excavation of material caused by such a build-up may be obviated or at least minimised. The materials source may be a storage vessel, silo, a ship hold, a building such as a warehouse or any other suitable source. The material withdrawing means may include a vacuum chamber for receiving material from the material source, and vacuum means for creating a vacuum in the vacuum chamber for drawing material into said vacuum chambers . Two or more such material withdrawing means may be provided. Conveniently, the apparatus comprises a plurality of material transportation conduits. The conduit inlets may be spaced laterally and arrayed around a base of the material source, to withdraw material from selected locations within the material source. Preferably each material transportation conduit includes a valve which may be actuated between an open and a closed position to selectively allow passage of material through a selected conduit. Preferably only one valve is open at any one time to allow material to be withdrawn via a single, selected conduit. Alternatively, material may be withdrawn from more than one selected material transportation conduit simultaneously. Conveniently, the material transportation conduits include a nozzle at the inlet to each conduit. The apparatus may further comprise gas injection means for injecting a gas into the material in the material source to aerate said material for aiding withdrawal thereof. The gas injection means may comprise a gas injection conduit coupled to a gas supply, the gas injection conduit having an outlet disposed in the material source. Alternatively, the apparatus may further comprise a conduit having an inlet open to atmosphere, to allow.gas to be supplied to the material in the material source through an outlet, to aerate said material for aiding withdrawal thereof. The outlet may be disposed adjacent to the inlet of the materials conduit. According to a fourth aspect of the present invention, there is provided a method for the transportation of solid particulate material from a material source, comprising the steps of: providing means for withdrawing material from the material source ; providing at least two material transportation conduits, each having a material inlet; disposing the inlets of each material transportation conduit spaced apart in the material source; and selectively coupling a selected material transportation conduit to the material withdrawing means to selectively withdraw material from the material source. Preferably, the step of providing means for withdrawing material from the material source comprises withdrawing material into a first chamber. The material may be withdrawn into the first chamber by creating a vacuum in the first chamber. According to a fifth aspect of the present invention, there is provided a base for a storage container, the base comprising inclined side walls for directing material to at least two lower discharge locations. Thus the present invention may allow material to be withdrawn from a storage container without a build-up of material, as the material is directed to the discharge locations from where it may be discharged from the container, and thus does not become built-up in regions of the storage container which cannot be accessed for material withdrawal. The base may be adapted to be located in an existing storage container. This may allow the base to be located in an existing storage container in a retro-fit. Alternatively, the base may be provided as an integral part of a storage container. Thus a storage container may be constructed to incorporate the base. The inclined side walls of the base may provide the side walls for the storage container. Alternatively, the storage container may have side walls separate from the side walls of the base. Preferably, there are a plurality of discharge locations, and the base further comprises a number of internal inclined walls which direct materials to the discharge locations. The internal inclined walls may define a number of material hoppers, which taper towards a lower discharge location. Conveniently, the material hoppers are hexagonal in cross-section. This may facilitate construction of the base as the hexagonal hoppers fit together in a honeycomb pattern. Alternatively, the hoppers may be circular, quadrilateral, or any other suitable shape in cross-section. The material hoppers may be of steel sheet and may be welded or bolted together to form the insert. Alternatively, the material hoppers may be of aluminium alloy sheet, concrete, a glass- lined metal sheet such as a vitreous enamel lined metal sheet, a fibre glass composite resin material, or indeed any appropriate material. Preferably, the lower portion of each hopper tapers to a point which defines the discharge location. This may allow material to be withdrawn by disposing an inlet of a material transportation conduit at the discharge location. Alternatively, the lower portion of each hopper may have a discharge aperture. This may enable material to discharge by free-flow from the discharge aperture. In a further alternative, the base may comprise a cone-shaped insert which, together with the inclined side walls, define an annular, tapering channel defining the at least two lower discharge locations. According to a sixth aspect of the present invention, there is provided a method of modifying a storage container comprising the steps of: providing a base for the storage container, the base having inclined walls which define tapering material hoppers for directing material within the storage container towards at least two discharge locations; and locating the base within the storage container. Preferably, the base is coupled to the storage container to seal the base to the container. Thus the present invention may allow an existing storage container to be modified by the location of a shaped base within the container, to direct material towards the discharge locations and therefore prevent the build-up of material; a storage container, such as an oil tank, may thus be converted to a silo suitable for storing solid particulate material . Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig 1 is a side view of a material transportation and storage apparatus in accordance with an embodiment of the present invention; Fig 2 is a side view of the apparatus of Fig 1 shown coupled to a material storage silo; Fig 3 is a cross-sectional side view of part of the apparatus of Fig 1 shown including a gas injection conduit; Figs 4A to 4F are cross-sectional views of an apparatus similar to the apparatus of Fig 1, showing the apparatus during transportation and storage of material, from start-up of the apparatus in Fig 4A, to continuous flow of material in Fig 4F; Figs 5A to 5C are schematic cross-sectional side views of the apparatus of Fig 1 being used to transport material from the hold of a ship, a storage silo and a storage building respectively, the apparatus including multiple material transportation conduits; Fig 6 is a schematic cross-sectional plan view of apparatus for the transportation of material in accordance with an alternative embodiment of the present invention; Fig 7 is a side view of a silo having two of the material transportation and storage apparatus of Fig 1 coupled thereto, and including a material transportation apparatus similar to the apparatus of Fig 6; Fig 8 is a cross-sectional plan view of the silo of Fig 7; Figs 9A and 9B are plan views of a base for a storage container in accordance with an alternative embodiment of the present invention; Fig 10 is a side view of a storage container including the base of Figs 9A and 9B, and showing apparatus for transporting material from the storage container; Figure 11 is a schematic sectional side view of a material withdrawal arrangement; Figures 12A and 12B are schematic plan and sectional side views of a further withdrawal arrangement; Figures 13A and 13B are schematic side and plan views of storage containers in accordance with an embodiment of the present invention; and Figure 14 is a schematic plan view of a storage container in accordance with a further embodiment of the present invention, including an alternative material transport arrangement . Referring firstly to Fig 1, there is shown an apparatus for the transportation and storage of solid, particulate material, the apparatus indicated generally by reference numeral 10. The apparatus 10 includes an upper vacuum chamber 12, an intermediate chamber 14, a lower discharge chamber 16, a material inlet conduit 18, a vacuum pump 20, a vacuum conduit 22, a compressor ("or blower") 24 and a discharge conduit 26. The vacuum chamber 12 is coupled to the vacuum pump 20 via the vacuum conduit 22, and the material inlet conduit 18 is coupled to the vacuum chamber 12. Also, the vacuum chamber 12 is coupled to the intermediate chamber 14, and includes a material flow valve 28 disposed between the vacuum chamber 12 and the intermediate chamber 14. The vacuum chamber 12 is also coupled to the intermediate chamber 14 via a pressure equalisation conduit 30 which includes a valve 32. In turn, the intermediate chamber 14 is coupled to the discharge chamber 16 via a material flow valve 34, and a pressure equalisation conduit 36, which includes a valve 38. Also, the discharge chamber 16 is coupled to the discharge conduit 26 at an outlet 40 of the discharge chamber 16, and the compressor 24 is coupled to the discharge conduit 26. Referring now to Fig 2, the apparatus 10 of Fig 1 is shown coupled to a silo 42 for the discharge of solid particulate materials from the silo 42 via material inlet conduit 18, which has an inlet 44 in the silo 42. To withdraw material from the silo 42, the vacuum pump 20 is activated, creating at least a partial vacuum in the vacuum chamber 12 which draws material from the silo 42 via conduit 18. Meanwhile, the compressor 24 is activated, creating a flow of air through the discharge conduit 26 in the direction indicated by the arrow A. The vacuum chamber 12 includes a level sensor (not shown) , such that when the material in the vacuum chamber 12 reaches a predetermined level, the material is discharged from the vacuum chamber 12 to the intermediate chamber 14, and from there into the discharge chamber 16, to then be discharged via discharge conduit 26, as will be described in more detail below. The discharge chamber 16 also includes a level sensor 46 to regulate the flow of material from the intermediate chamber into the discharge chamber. Referring now to Fig 3, the material inlet conduit 18 is shown in more detail. The inlet 44 of the conduit 18 is shown cut-away such that the relative positioning of the outlet 50 of gas injection conduit 48 to the inlet 44 of conduit 18 can be seen. The material inlet conduit 18 includes a material flow valve 52 which may be actuated between open and closed positions to allow materials to flow through the conduit 18 to the vacuum chamber 12, and the inlet 44 of the conduit 18 includes a nozzle (not shown) shaped to achieve optimum withdrawal of the solid particulate material from the silo 42. A gas may be drawn into the material in the silo 42 via the gas induction conduit 48, whose outlet 50 is disposed adjacent to the inlet 44 of conduit 18. This gas aerates the material in the proximity of the inlet 44 to aid withdrawal of the material, and is used where large volumes of material are to be withdrawn, or where it proves difficult to draw air through the material, thereby hampering withdrawal. The flow of gas is adjusted until the optimum withdrawal of material is obtained. There follows a more detailed description of the operation of the material transportation and storage apparatus of Figs 1 to 3. Referring now to Figs 4A to 4F, there is shown the various stages in the storage and transportation of solid particulate material by the apparatus 10 of Fig 1 from start-up at Fig 4A, to the continuous supply of material at Fig 4F. In Figs 4A to 4F, the vacuum pump 20, conduit 22, material inlet conduit 18 and the upper portion of the vacuum chamber 12 have been removed for clarity. In Fig 4A, the vacuum pump 20 has been activated, and a volume of solid particulate material 54 has been withdrawn from the silo 42 into the chamber 12. The material flow valve 28 is initially closed and remains closed until the material 54 in the chamber 12 reaches a pre-determined level, measured via a level sensor (not shown) . The air pressure within the vacuum chamber 12 is approximately -700 mbarg (gauge pressure) . The valve 32 is initially closed such that the vacuum chamber 12 is isolated from the intermediate chamber 14. The compressor 24 is activated, and air is discharged along the discharge' conduit 26 in the direction indicated by the arrow "B". The discharge chamber 16, which is coupled to the discharge conduit 26, experiences a positive air pressure of between 100 mbarg up to 6 barg and the intermediate chamber 14 likewise experiences a positive pressure. Turning now to Fig 4B, the materials 54 in the vacuum chamber 12 have now reached the predetermined level . The valve 32 of the pressure equalisation conduit 30 is opened to equalise pressure between the vacuum chamber 12 and intermediate chamber 14, to prevent "blow-back" of materials when the material flow valve 28 is opened. Thus the intermediate chamber 14 now experiences an air pressure in the region of -700 mbarg similarly to the vacuum chamber 12, and remains isolated from the discharge chamber 16; the valve 34 and a valve 39 in the pressure equalisation conduit 36 remain closed. The material flow valve 28 is then opened to allow material to flow from the vacuum chamber 12 to the intermediate chamber 14. When the intermediate chamber 14 has been filled to a predetermined level, measured by a suitable level sensor (not shown), the valves 28 and 32 are closed, as shown in Fig 4C. During this time, material 54 continues to be withdrawn from the silo or the like into the vacuum chamber 12, with initially withdrawn material having been discharged into the intermediate chamber 14. Turning now to Fig 4D, the valves 38 and 39 are then opened to equalise pressure between the intermediate chamber 14 (experiencing a pressure in the region of -700 mbarg) and the discharge chamber 16 (experiencing a positive pressure of up to 6 mbarg) , again to prevent a "blow-back" of materials 54 when material flow valve 34 is opened. When the pressure has been equalised, the valve 34 is opened to allow material to flow into the discharge chamber 16. Turning now to Fig 4E, the material 54 flows freely from the discharge chamber 16 into the discharge conduit 26 under gravity, and subsequently travels along the discharge conduit 26 in the direction of air flow. Discharge conduit 26 transports the material 54 along its length to an outlet (not shown) which may discharge the materials 54 directly onto a conveyor, into a vehicle, a secondary storage silo, a ship hold or the like. When the material 54 in the discharge chamber 16 has reached the predetermined level measured by the level sensor 46 (not shown in Figs 4A to 4F) , the valves 34, 38 and 39 are closed, whilst the materials 54 continue to discharge from the discharge chamber 16, to isolate the discharge chamber 16 from the intermediate chamber 14, in preparation for the intermediate chamber 14 receiving further material 54. Meanwhile, material 54 is continuing to be withdrawn from the silo or the like into the vacuum chamber 12, and when the level of the material in the vacuum chamber 12 reaches the predetermined level, material is discharged from the vacuum chamber 12 into the intermediate chamber 14 by repeating the steps of Figs 4A to 4C. Simultaneously, the level of material in the discharge chamber 16 is decreasing. Thus, when further material 54 has been discharged from the vacuum chamber 12 into the intermediate chamber 14, the valves 28 and 32 are closed, pressure is equalised between the intermediate chamber 14 and the discharge chamber 16 (by opening valves 38 and 39) , and valve 34 is then opened to discharge materials into the discharge chamber 16. Thus it will be appreciated that, by regulating the flow of- material between the chambers 12, 14 and 16, a continuous flow of material through the discharge conduit 26 may be achieved. Furthermore, the vacuum chamber 12 has a higher storage capacity than either of the intermediate chamber 14 or the discharge chamber 16, and thus material may be continuously withdrawn from the silo or the like into the vacuum chamber 12. The system is controlled and regulated via a suitable control system which activates and deactivates the vacuum pump 20, compressor 24, valves 28, 32, 34, 38, 39 and 52 (shown in Fig. 3) according to the levels of the material 54 in the various chambers . Also, the vacuum conduit 22 and the pressure equalisation conduits 30 and 36 include filters (not shown) to prevent any of the solid particulate material 54 from entering any of these conduits . Filters (not shown) in the vacuum chamber 12 prevent any materials passing through the conduit 22 to the vacuum pump. When necessary, a compressed air "shock" may be applied to the filters to clean them and remove any caked- on solids. Referring now to Figs 5A to 5C, there is shown the material transportation and storage apparatus 10 of Figs 1 to 4F in use discharging material 54 from the hold 56 of a ship 58, from a storage silo 60, and a storage building such as a warehouse 62, respectively. Also shown in Figs 5A to 5C is an apparatus for the transportation and storage of materials indicated generally by reference numeral 64, in accordance with an alternative embodiment of the present invention. The apparatus 64 comprises a main material conduit 66, similar to the material inlet conduit 18 of the apparatus 10 of Fig 1, and a number of secondary material conduits 68 which are coupled to the main material conduit 66. Each of the secondary material conduits 68 includes a valve 70, which may be actuated between an open and a closed position, to selectively withdraw the material 54 from the ship 58, silo 60, or storage building 62 respectively. When the apparatus 64 is coupled to a material transportation and storage apparatus such as the apparatus 10 of Fig 1, material 54 may be selectively withdrawn from, for example, the ship 58 via any one of the selected secondary conduits 68, and the main conduit 66. The conduits 68 are disposed in a fixed array and spaced around the ship 58 to enable withdrawal of material 54 from multiple locations within the ship 58. This helps to minimise the build-up of material in locations in the ship 58 which could not be accessed by a single conduit 68. It will be appreciated by persons skilled in the art that any appropriate number of conduits 68 may be provided. The apparatus 66 includes a gas induction conduit 72 associated with each secondary conduit 68, similar to the gas induction conduit 48 of Fig 3. Referring now to Fig 6, there is shown a material transportation apparatus similar to the apparatus 64 of Figs 5A to 5C, and indicated generally by reference numeral 74. The apparatus 74 is coupled to the apparatus 10 of Fig 1 and includes a main material conduit 66 which is coupled to branch conduits 76 via a three-way valve 78, which may be actuated between a number of positions, to allow the withdrawal of material via either one of the branch conduits 76, or in certain circumstances, from both conduits 76 simultaneously. Each of the branch conduits 76 has a number of secondary material conduits 68 coupled thereto, each of the secondary conduits 68 having an inlet 80 in a silo 82. Each of the secondary conduits 68 includes a valve (not shown) which may be actuated between open and closed positions in order to allow selective withdrawal via a selected conduit 68. Typically material is withdrawn from the silo 82 via a single, selected conduit 68 at any one time. The provision of a plurality of such secondary conduits 68 enables an inlet 80 of each conduit 68 to be located spaced around the base of the silo 82, to enable the withdrawal of material over a wide area. This avoids the build-up of material in sections of the silo 82, ensuring a continuous supply of material from the silo 82, and this ensures consistent depletion of the level of material. The conduit 68 which is selected for withdrawal of material is alternated on a controlled basis, which may vary from a time period of two minutes up to approximately two hours per conduit 68, following which an alternative conduit 68 is selected for withdrawal. This process is repeated to selectively withdraw material from all of the conduits 68. To aid this process, the silo 82 may include a shaped internal base, as will be discussed in more detail below with reference to a further alternative embodiment of the present invention shown in Figs 9A to 10. The silo 82 includes a central material distribution cone 112 and inclined internal side walls 114, which together direct material in the silo 82 towards an annular discharge area 116. The material conduits 68 of the apparatus 74 are disposed with their respective inlets 80 in the discharge area 116. In directing material to the discharge area 116, the volume of material which cannot be accessed via the conduits 68 is minimised, and therefore the number of conduits 68 otherwise required is reduced. Referring now to Figs 7 and 8, there is shown a material transportation apparatus similar to the apparatus 66 of Figs 5A to 5C, and indicated generally by reference numeral 84. A silo 85 is shown coupled to the apparatus 84 and an apparatus for transportation and storage of material, such as the apparatus 10 of Fig 1. In the embodiment of Fig 7, two such apparatus 10 are provided located on opposite sides of the silo 85. The apparatus 84 is similar to the apparatus 74 of Fig 6 and like parts share the same reference numerals . The provision of two such apparatus 10 enables material to be withdrawn from the silo 85 via two inlets 80 of the apparatus 84 simultaneously, on opposite sides of the silo 85. This is achieved by withdrawing material via a selected conduit 68 associated with each apparatus 10. It will be appreciated that any suitable arrangement of the secondary conduits 68 of the apparatus 64 shown in Figs 5A to 5C may be provided, depending upon the dimensions and storage capacity of the relevant silo, and upon other requirements, such as the required withdrawal rate of material from the silo. The silo 85 also includes a central material distribution cone 212 and inclined side walls 214 which together divert material in the silo 85 towards an annular discharge area 216, in a similar manner to the cone 112 and walls 114 of silo 82. Referring now to Fig 9A, there is shown an apparatus for the storage of material in accordance with a further alternative embodiment of the present invention, comprising an insert for the base of a silo, the insert indicated generally by reference numeral 86. The insert 86 is constructed from sheet metal, typically steel, and is located in the flat-bottomed base of a silo such as the silos 42, 60, 82 or 85 of Figs 2, 5B or Figs 6 to 8, which are generally cylindrical, of relatively large diameter, and having a flat-bottom which receives the insert 86, which is welded or otherwise sealed to the inner surface of the side wall (not shown) of the silo. The insert 86 includes a number of material hoppers 88 which are generally hexagonal in plan and which are welded together. The hoppers 88 each have a rim 90, and taper from the rim 90 towards a discharge area 92 disposed lowermost in the insert 86. The hexagonal construction of the hoppers 88 facilitates construction of the insert 86 as it reduces the number of voids, and enables the hoppers 88 to be constructed from a number of shaped plates, as will be described below with reference to Fig 9B . The void areas 94 where the insert 86 abuts the silo are filled either with further shaped hoppers, or with an angled steel sheet, inclined towards the wall of the silo. Material is discharged from the silo in the region of the discharge areas 92 using a suitable discharge system, such as the apparatus 64 of Figs 5A to 5C, incorporating material conduits 68. A material conduit 68 is provided for each hopper 88, with the inlet 80 of each conduit 68 disposed in the discharge area 92, which is lowermost in the insert 86. Alternatively, each discharge area 92 may define an opening, through which material may pass under the influence of gravity, and in combination with which a screw conveyer, gravity assisted air slide, conveyer, vibrator or the like of types known in the art may be utilised. Referring now to Fig 9B, the structure of the hoppers 88 of the insert 86 of Fig 9A is shown in more detail. In particular, the individual panels 96 of each material hopper 88 are shown. Each of the panels are welded together to form the material hoppers 88, and each of the hoppers 88 are subsequently fixed to adjacent hoppers 88 to form the insert 86. The panel 96 disposed adjacent to the wall of the silo has an arcuate rim portion 98, to conform with the cylindrical wall of the silo. It will be appreciated by persons skilled in the art that any suitable number of hoppers 88 may be provided, of suitable dimensions to suit the particular silo in which the insert 86 is to be located. ' Referring now to Fig 10, there is shown a silo 100 having an insert 102 similar to the insert 86 of Figs 9A and 9B . The insert 102 includes material hoppers 104. In the embodiment of Fig 10, a solid particulate material 106 is withdrawn from the silo 100 through the material hoppers 104. The hoppers 104 each have an outlet 108 lowermost in the insert 102, through which the material 106 is withdrawn using, for example, conventional "suck-blow" transportation apparatus 110, as an alternative to the apparatus described above which withdraws material via conduits 68 inserted from the top of the relevant silo. The apparatus 110 comprises a lock hopper 118 and a discharge chamber 120, coupled to suitable discharge apparatus (not shown) , such as a discharge conduit. The lock hopper 118 alternatively experiences atmospheric pressure and is then pressurised for discharge to chamber 120. The hopper 118 is fed gravity from the silo at atmospheric pressure and then isolated from the silo. Pressure is then balanced with the chamber 120 for discharge, and a constant flow is provided from the chamber 120. Reference is now made to Fig.11 of the drawings, which illustrates an alternative material withdrawal arrangement 130 shown located in the lower part of an insert hopper 132, similar to the hoppers 104 described above. However, the lower or discharge area 134 of the hopper 132 is blanked off, and material 136 is withdrawn from the hopper 132 via a material conduit 138 having a flared inlet 140. Also, an atmospheric air inlet conduit 142 leads to an annular outlet 144 around the inlet 140. This arrangement facilitates aeration of the material 136, and minimises the possibility of blockage of the inlet 140. Reference is now made to Figs. 12A and 12B of the drawings, these figures illustrating an alternative twin- outlet hopper 150, in which the hopper discharge area 152 defines an elongate slot in communication with a pair of outlet valves 154, 156, facilitating gravity-fed material withdrawal. The valves 154, 156 may be opened together or in isolation and may feed the same or different material transport arrangements. Reference is next made to Figs. 13A and 13B of the drawings, which illustrate a silo 160 provided with a base 162 formed of a plurality of nineteen hexagonal tapering hoppers 164. All but the central hopper 164 selectively communicates through an outlet opening with one of nine screw auger conveyors 166, which are arranged to carry material from the outlet openings to a point below the central hopper 164, from where a chain conveyor 168 carries the material to a discharge point 170. Fig.14 illustrates a similar hopper 180, provided with an alternative conveyor configuration. Various modifications may be made to the foregoing within the scope of the present invention. For example, the apparatus 10 may discharge material from the discharge chamber 16 directly into a vehicle, storage container, or directly onto a material conveyor, or any suitable conveying means. The apparatus 10 may withdraw material from more than one single selected material conduit 68. This may be achieved by providing a vacuum chamber 12, intermediate chamber 14 and discharge chamber 16 of greater internal volume to accommodate larger volumes of material, and by providing a vacuum pump 20 of a higher capacity to enable the vacuum chamber 12 to withdraw material from multiple selected conduits 68. The apparatus 10 may include a plurality of material inlet conduits 18 which may each include a material flow valve to selectively allow material to be withdrawn through each conduit 18. The apparatus 10 may therefore be connected to a number of the apparatus 64, 74 or 84 either disposed within a single silo or the like, or disposed within separate silos, such that the apparatus 10 may withdraw material from selected points within a single silo, or from multiple silos or the like. The material hoppers 88 of the insert 86 may be of any suitable shape in cross-section, for example, circular or quadrilateral, with any voids formed between adjacent hoppers filled with suitably shaped void hoppers, angled sheets, or the like. The apparatus 64, 74 and 84 may used for storing flake ice and may be cladded for insulation purposes to prevent melting; or may be used for storing sugar, requiring similar insulation. Gas may be injected by the conduits 48, 72 for very fine particulate materials. The material hoppers may be of aluminium sheet, concrete, or a glass-lined metal sheet such as a vitreous enamel liner metal sheet, or a fibre-glass composite resin material . Silos provided with the material hoppers may discharge directly into vehicles or other vessels, or conveyors may carry material from the hoppers to a single outlet, or may carry material to be mixed with material from other silos before discharge.

Claims: CLAIMS 1. A base for a storage container, the base comprising inclined side walls for directing descending material in the container towards at least two spaced discharge locations . 2. A base as claimed in claim 1, wherein there are a plurality of discharge locations, and the base further comprises internal inclined walls for directing material to the discharge locations. 3. A base claimed in claim 2, wherein the inclined walls define a plurality of hoppers, each hopper tapering towards a lower discharge location. 4. A base as claimed in claim 3 , wherein the hoppers are hexagonal . 5. A base as claimed in claim 4, wherein the hexagonal hoppers are configured in a honeycomb pattern. 6. A base as claimed in claim 3, wherein the hoppers are circular. 7. A base as claimed in any one of claims 3 to 6, wherein the hoppers are formed of metal sheet . 8. A base as claimed in any of the preceding claims, in combination with a plurality of material transportation conduits each having an inlet at a respective discharge location. 9. A base as claimed in any of claims 2 to 8 , wherein a lower portion of each hopper defines a discharge opening. 10. A base as claimed in claim 1, wherein the base comprises a cone-shaped insert which, together with the inclined side walls, defines an annular, tapering channel defining the at least two discharge locations. 11. A base as claimed in any preceding claim, wherein each discharge location is in selective communication with a material conveyor. 12. A base as claimed in any of the preceding claims, wherein the base is adapted to be located in an existing storage container. 13. A storage container comprising a base in accordance with any of the preceding claims. 14. A method of modifying a storage container comprising the steps of : providing a base for the storage container, the base having inclined walls which define tapering material hoppers for directing descending material within the storage container towards at least two spaced discharge locations; and locating the base within the storage container. 15. Apparatus for the transportation of solid particulate material from a material source, the apparatus comprising: a vacuum chamber for receiving material from a material source; a vacuum means for creating at least a partial vacuum in the vacuum chamber for drawing material into said vacuum chamber; an intermediate chamber for selective communication with the vacuum chamber for receiving material from the vacuum chamber; and a discharge chamber for selective communication with the intermediate chamber for receiving material from the intermediate chamber, and the material being dischargeable from the discharge chamber. 16. Apparatus as claimed in claim 15, wherein the apparatus further comprises a conveying means for conveying material discharged from the discharge chamber. 17. Apparatus as claimed in claim 16, wherein the conveying means comprises a conveying conduit coupled to the discharge chamber and to a compressor, the conduit having at least one outlet distal from the discharge chamber . 18. Apparatus as claimed in any one of claims 15 to 18 wherein, the apparatus is a self-contained unit adapted for location outwith a material source. 19. Apparatus as claimed in any one of claims 15 to 18, wherein, the vacuum chamber is disposed uppermost of the vacuum, intermediate and discharge chambers, and the discharge chamber is disposed lowermost. 20. Apparatus as claimed in any one of claims 15 to 19, wherein the vacuum chamber, the intermediate chamber and the discharge chamber comprise pressure vessels. 21. Apparatus as claimed in any of claims 15 to 20, wherein a material inlet of the vacuum chamber is coupled to a material conduit. 22. Apparatus as claimed in any one of claims 15 to 21, wherein the apparatus further comprises gas injection means for injecting a gas into the material in the material source, to aerate the material for aiding withdrawal thereof. 23. Apparatus as claimed in claim 22, wherein the gas injection means comprises a conduit for coupling to a gas supply, the gas injection conduit having an outlet disposed in the material source. 24. Apparatus as claimed in claim 23 wherein the gas supply is atmospheric air. 25. Apparatus as claimed in any one of claims 15 to 24, wherein the vacuum means comprises a vacuum pump coupled to the vacuum chamber via a vacuum conduit. 26. Apparatus as claimed in any one of claims 15 to 25, wherein a first material flow valve is disposed between an outlet of the vacuum chamber and an inlet of the intermediate chamber, a second material flow valve is disposed between an outlet of the intermediate chamber and an inlet of the discharge chamber, and the material flow valves are adapted to be actuated between an open and a closed position to selectively allow material to flow between the respective chambers. 27. Apparatus as claimed in any one of claims 15 to 26, wherein the apparatus further comprises means for equalising the pressure between selected ones of the chambers . 28. Apparatus as claimed in claim 27, wherein the means for equalising the pressure comprises a conduit coupled at one end to a selected one of said chambers, and at an opposite end to a selected second one of said chambers, to allow fluid communication between said selected chambers and a fluid flow valve disposed in the conduit and which is actuated between an open and a closed position to selectively allow fluid communication between the said chambers . 29. Apparatus as claimed in claim 28, wherein said equalising means further comprises a filter to prevent the solid particulate material from passing through the conduit . 30. A method for the transportation of solid particulate material from a material source, the method comprising the steps of: creating at least a partial vacuum in a first chamber and drawing material from the material source into the first chamber; selectively discharging material from the first chamber into an intermediate chamber; selectively discharging material from the intermediate chamber into a discharge chamber; and continuously discharging material from the discharge chamber . 31. A method as claimed in claim 30, the method further comprising the step of conveying material discharged from the discharge chamber to a remote discharge point. 32. A method as claimed in claim 31, wherein the step of conveying material comprises providing a discharge conduit having at least one outlet and an inlet which is in communication with the discharge chamber, and creating a flow of gas through the discharge conduit to transport the material. 33. Apparatus for the transportation of solid particulate material from a material source, the apparatus comprising: a material withdrawing means for withdrawing material from the material source; and at least two material transportation conduits, selectively coupled to the material withdrawing means, and each having an inlet in the material source for transporting material therefrom, wherein said inlets are disposed spaced apart in the material source to selectively withdraw material from at least two spaced locations therein. 34. Apparatus as claimed in claim 33, wherein a plurality of material transportation conduits are provided. 35. Apparatus as claimed in claim 34, wherein the material transportation conduits are selectively coupled to the means for withdrawing material by providing a valve associated with each material transportation conduit and which valve is actuated between an open and a closed position. 36. Apparatus as claimed in any one of claims 33 to 35, wherein the material withdrawing means includes a vacuum chamber for receiving material from the material source, and vacuum means for creating at least a partial vacuum in the vacuum chamber for drawing material into said vacuum chambers . 37. Apparatus as claimed in claim 36, wherein two or more such material withdrawing means are provided. 38. Apparatus as claimed in any one of claims 33 to 36, wherein the apparatus comprises a plurality of material transportation conduits. 39. Apparatus as claimed in claim 38, wherein the conduit inlets are adapted to be spaced laterally and arrayed around a base of a material source, to withdraw material from selected locations within the material source.

Inventors: CURLE WILLIAM, CURLE, WILLIAM
Applicants: CURLE WILLIAM, CURLE, WILLIAM
Application year: 2000
Main classification: B65D88
IPC codes: B65D88, B65G53