WO1996030727A1

WO1996030727A1 - Discharge chute for non-flowable bulk materials

Info

Publication number: WO1996030727A1
Application number: PCT/US1996/003900
Authority: WO
Inventors: James H. Hara
Original assignee: Skarhar, Inc.
Priority date: 1995-03-31
Filing date: 1996-03-22
Publication date: 1996-10-03
Also published as: AU5427796A

Abstract

In a preferred embodiment, a method of promoting discharge of essentially non-flowable material (21) through a bottom opening (30) of a container (20) within which the material is stored, including the steps of: slowly applying pressure to upwardly press at least a lower portion of mass of the material; and thereafter, releasing the pressure, whereby portions of the material fall through the bottom opening.

Description

Discharge Chute for Non-Flowable Bulk Materials

Technical Field

The present invention relates generally to the discharge of bulk material, essentially non-flowable in nature, from storage containers and, more particularly, but not by way of limitation, to method and means for causing non-flowable bulk material to discharge through an opening at the bottom of a bin or hopper.

Background Art

While it will be understood that the present invention may be useful for unloading any essentially non-flowable bulk material from any container, such as a storage bin or hopper, the invention is herein described, for illustrative purposes only, in connection with the design of the cargo holds for a self-unloading cargo vessel for carrying non-flowable materials such as limonitic nickel ore or synthetic gypsum.

High grade limonitic nickel ore as is a red-brown, clay-like material which is actually limonite containing a significant percentage of nickel ore and having an average moisture content of from about 35% to about 40%. Typically it is constituted of up to 5% gravel, 10% to 12% coarse and fine sands, 39% to 41% silt, and 42% to 46% clay. Having particle sizes up to only 1 millimeter, its bulk density is 1.4 metric tons per cubic meter, and its angle of repose is often as steep as 90 degrees from the horizontal. Thus, it may be characterized as a heavy, wet and sticky, non-flowable particulate material which is very difficult to retrieve from a hopper or bin storage facility, such as the hold of a ship. For example, if the material is stored in a hopper having a bottom opening closed by a gate, when the gate is opened the material will not flow through the opening but will "hang-up" within the hopper, bridging or arching across the bottom opening. For that reason, such bottom-opening hoppers have not been used to store such material except when imposed by necessity, as when the material must be transported by ship. When dropped into the cargo hold of a ship during loading and then subjected to the motions incidental to an ocean voyage, it becomes compacted within the hold and is dislodged only with considerable difficulty using picks, or water or air jets or the like directed at the mass. Because of its weight and density, even shovelling of the material is very difficult.

The common technique for unloading such material from the cargo hold or a ship is to use a crane-hoisted grab bucket whose opened jaws are dropped onto the material through the opened top of the cargo hold whereupon, as the bucket is lifted, its closing jaws grasp and collect a quantity of the material within the bucket. However, the material is so dense and clay-like in nature that the jaws, either when dropped onto the material through the opened hold or as the bucket is being closed, do not penetrate substantially the mass of material and, consequently, the bucket is only partly filled as it closes. Thus, it is common practice to lower a bulldozer into the hold to operate on top of the stored material, constantly heaping it towards a peak at which the open-jawed bucket can grasp a greater quantity of the material with each bite. The bulldozing is augmented by shovelling and waterjetting to finally remove the cargo from the hold.

It is apparent that such conventional unloading techniques are costly and time consuming, and it is therefore generally believed that bulk cargos of such material are not efficiently transported by ship. Of course, the unloading problem would be the same were the material to be stored in silos or hoppers on land, for example, at the refinery. For the same reasons as described with respect to its unloading from a ship's cargo hold, the nickel ore is more often stored in piles on large ground storage areas to facilitate its subsequent retrieval using the aforementioned grab bucket and bulldozer gathering techniques.

Another difficult to handle material having similar physical and non-flowing characteristics to nickel ore is synthetic gypsum produced in flue gas desulphurization processes in which lime is employed to react with the sulphur.

Accordingly, it is a principal object of the present invention to provide method and means for the storage and discharge of non-flowable bulk material which permits the material to be stored in containers.

It is a further object of the invention to provide such method and means by which such bulk material can be automatically removed from a storage container, such as ^a ship's hold, in manner similar to that in which flowable bulk may be self-unloaded through an opening in the bottom of the storage container.

It is an additional object of the invention to provide such method and means to permit more rapid, more efficient, and less costly unloading of such materials. It is another object of the invention to provide such means that is easily and economically constructed and which can be installed in otherwise conventional storage containers. Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures. Disclosure of Invention

The present invention achieves the above objects, among others, by providing, in a preferred embodiment, a method of promoting discharge of essentially non- flowable material through a bottom opening of a container within which said material is stored, comprising the steps of: slowly applying pressure to upwardly press at least a lower portion of mass of said material; and thereafter, releasing said pressure, whereby portions of said material fall through said bottom opening.

Brief Description of Drawings

Understanding of the present invention and the various aspects thereof will be facilitated by reference to the accompanying drawing figures, submitted for purposes of illustration only and not intended to define the scope of the invention, on which:

Figure 1 is a fragmentary and diagrammatic cross- sectional view of a hopper for non-flowable bulk materials incorporating one form of the invention.

Figures 2A, 2B and 2C are diagrammatic cross- sectional illustrations useful for explaining the operation of the invention. Figure 3 is a diagrammatic cross-sectional view through a middle body portion of an ocean-going bulk cargo carrying vessel incorporating a modified form of the invention as a feature thereof.

Figure 4 is a fragmentary, cross-sectional profile of another ocean-going bulk cargo carrying vessel incorporating the presently preferred embodiment of the invention as a feature thereof.

Figure 5 is a fragmentary deck plan view, partially cut-away, of the vessel to an enlarged scale, taken along line "5-5" on Figure 4, as the vessel would appear when moored at an off-loading shore facility. Figure 6 is a further enlarged and diagrammatic cross-sectional view taken through a middle body portion of the vessel along line "6-6" on Figure 4.

Figure 7 is a perspective and fragmentary perspective view of portions of a laterally adjacent pair of cargo holds in the ship of Figure 4.

Figure 8 is a fragmentary and diagrammatic cross- sectional side elevational view, to a further enlarged scale, of one of the hopper chutes at the bottoms of the cargo holds in the vessel of Figure 4.

Figure 9 is a diagrammatic cross-sectional view through a middle body portion of an ocean-going bulk cargo carrying vessel incorporating another modified form of the invention as a feature thereof. Figures 10A and 10B are fragmentary diagrammatic illustrations of a principal feature shown in Figure 9, for explaining its operation;

Figure 11 is a diagrammatic cross-sectional view through a middle body portion of an ocean-going bulk cargo carrying vessel incorporating still another modified form of the invention as a feature thereof.

Figure 12 is a fragmentary and diagrammatic perspective illustration of a further modified form of the invention.

Best Mode for Carrying Out the Invention

Reference should now be made to the drawing figures, on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers direct the reader to the view(s) on which the element(s) being described is (are) best seen, although the element(s) may be seen also on other views. Referring first to Fig. 1, a hopper for storing essentially non-flowable material 21 in bulk, such as the previously described limonitic nickel ore or synthetic gypsum, is generally indicated by the reference numeral 20. Hopper 20 is defined by opposite vertical sidewalls 22, 23; opposite parallel and vertical endwalls, only one endwall 24 of which is partially shown in Fig. 1; and an angularly disposed movable flap or discharging panel 25 constituting all of what is the sloping bottomwall of the hopper. In the illustrated embodiment, the free and 25b of the movable panel 25 is pivotable about its fixed upper and 25a where it is rotatably connected via an elongated horizontally extending hinge 26 along the lower edge 23a of the hopper sidewall 23. The pivotal movement of the bottom panel 25 is powered by one or more horizontally or angularly disposed hydraulic rams 27 (only one of which is shown) connected via pivot connections 27a, 27b, between the panel 25 and a fixed location 28 exteriorly of hopper 20. Although not illustrated, it will be understood that the movement of each ran 27 is controlled by an hydraulic fluid pump and suitable valves for introducing and releasing fluid under pressure to and from the ram. Ram 27 is connected at a middle location along the length of the panel 25, whose extents of swingable movement respectively above and below its normal, full-lined position 25 are generally indicated by broken lines 25c, 25d.

The lateral spacing between the free, lower and 25b of the bottomwall panel 25 and the lower end 22a of the opposite vertical wall 22 defines a horizontally disposed hopper bottom discharge opening, generally indicated by the reference numeral 30, through which discharge opening bulk material 21 is intended to be gravity-discharged, as indicated by the vertical arrow, upon opening a laterally slidable hopper bottom gate 31 using an hydraulic ram (not shown) from its dotted-line closed position, closing the hopper bottom opening 30, to its opened position shown in fragmentary solid lines. A conveyor 32 therebelow includes conveyor rollers 32a, mounting a conveyor belt 32b which conveys material 21 away from bottom opening 30 as soon as the material falls therethrough. Of course, it will be appreciated that material 21 might also be discharged directly into a truck or the like, positioned beneath hopper opening 30, for subsequent carting to another location.

As previously noted, the bulk material 21 is essentially non-flowable material containing clay and having a very high water content, so that it compacts into a sticky mass when loaded into an open topped hopper such as hopper 20. Thus, upon opening bottom gate 31 by moving it from its broken-line or closed position to its solid-line or open position as shown on Figure 1, only a first slug or chunk 21a of the material may drop through the hopper discharge opening 30. The remainder of the material 21 "hangs up" within the hopper 20 because it tends to "arch across" opening 30, as indicated by line 21b, adhering to the walls and bottom of the hopper. Even poking the material at its arch 21b, using a shovel or rod or the like, fails to cause it to flow or otherwise continuously drop through opening 30. At best, a vertical "rat hole", generally indicated by dotted line 21c, will form through material 21 over opening 30, possibly extending to its top surface 2Id as some material falls therethrough, but the remainder will stay within hopper 20, at an angle of repose approaching 90 degrees adjacent the "rat hole".

To dislodge the material and cause it to substantially "flow" through the hopper bottom opening 30, movable panel 25 is located adjacent to the opening, at the deepest region within the hopper where material 21 is the most compacted. Its angular disposition and intended movement against and away from the underside of the mass will create an unstable condition within material 21 which will cause it to break off and tumble under its own weight, falling into any "rat hole" which may have formed and, in any event, through the opening 30. The repeated, slow maneuvering of the panel 25, first upwardly and then downwardly, sequentially recreates such instability within the material, causing successive, comparatively small lumps of it to break off frequently, thereby promoting flow through hopper opening 30.

The panel 25 normally reposes at an angle of from about 35 degrees to about 60 degrees from the horizontal, preferably 45 degrees. Its arc of pivotal movement is such as to press the free end of the panel upwardly a distance d-i into the contained material and, thereafter, a distance dz downward, i.e., radially from about 15 degrees above to about 15 degrees below its normal position, as indicated by broken lines 25c and 25d. Thus, the radial distance of panel movement is over an arc of about 30 degrees between its upper and lower positions 25c and 25d. Panel movement is induced by the reciprocal movement of the fluid powered ram 27, as indicated by the double arrow on Figure 1. This reciprocal movement upwardly and then downwardly is conducted at a slow rate, of up to about 4 cycles per minute, preferably about 2 cycles per minute, and may include a slight delay at the nodes or peak points of the cyclical movement.

Although the internal actions and reactions within mass 21 are not actually known, it is believed that the induced upward pressure creates an unstable condition within mass 21 due to the greater distance of movement into the mass, and therefore greater imparted work energy, of the outer, free and 25b of the panel 25 as compared with that of its pivotally connected inner end 25a. In a test of a one-fifth sized model it was observed that the central portion of the upper surface 21d of mass 21 was elevated about 100mm, to the dotted line position 21e in Fig. 1, responsive to 100 mm of vertically projected, upward movement d-i of the free end 25b of the panel 25. Some cracking or splitting apart of the material occurred within the area of its top surface 21d, as indicated on Figure 2A. Moreover, some compacting of material 21 occurred immediately adjacent to upwardly moving panel 25, most compaction occurring adjacent its outer, free end 25b and diminishing in amount in gradient fashion towards its inner, pivotal end 25a as indicated by the particle accumulations D on Figures 2A and 2B. During upward movement of panel 25, the particles of material 21 within region D appeared to stick together so that, during subsequent downward movement, a void space V (Figure 2B) was temporarily formed as the panel moved away from the pressed-together material D. This further destabilized the momentary unbalanced conditions of repose of material 21, so that the 21b (Figure 1) of material collapsed, resulting in a dropping of material 21 whose vertical momentum, in turn, appeared to establish shearing forces between distinct internal regions A and B (Figure 2C) of the remaining mass, which was sufficient to break off further quantities. This shearing action appeared to be augmented by the receding, angular disposition of downwardly moving panel 25, which permitted larger mass A to move some distance downwardly prior to any significant initial downward movement of mass B.

The unbalanced conditions established within the material 21 by the working movement of panel 25 are enhanced, and the resulting discharging flow of material is made more continuous where hopper sidewall 22, opposite panel 25, is vertical or substantially vertical, i.e., disposed at an angle of not more than about 20 degrees away from the vertical, and the unbalanced conditions are even further enhanced if sidewall 22 is lined with a sheet of friction-reducing material such as sheet lining 22e of ultra-high molecular weight (UHMW) polyethylene, as illustrated on Figure 1. Alternatively, a different plastic, or a stainless steel sheet, or a coating of an anti-abrasive paint might be used. A similar sheet 25e (Figure 1) of friction-reducing material may be attached to panel 25, and to the remaining walls of the hopper.

It is believed that the movement of angularly disposed discharging panel 25 works in conjunction with its opposed substantially vertical hopper sidewall 22 to induce the desired unbalanced internal conditions within the mass of the contained material 21 and that, for example, the use of an additional, similarly angularly disposed and movable panel in substitution of the wall 22, working oppositely to the panel 25, does not induce establishment of the desired unstable internal conditions of the contained material. Further, it is believed significant to the discharging action that free end 25b of panel 25 be spaced laterally a considerable distance away from the sidewall 22, to provide the horizontal bottom opening 30 therebetween, and that the free end not be immediately adjacent to sidewall 22. Moreover, the vertical height of hopper 20 is believed to be irrelevant to the discharging action, i.e., the induced flow of the material will occur even when the cargo fills a much deeper hopper, as is the cargo hold of a ship.

A test model hopper of approximately one-fifth (1/5) the size of the intended hopper in a cargo ship was built and operated successfully to provide substantially continuous flow of limonitic nickel ore material, as described, through a rectangular hopper bottom opening of approximately 0.95 meters (m) by 1.5 m. The test hopper, which would hold about 6 cubic meters of material, was 1.6 m wide in the direction of the movable panel (e.g., between sidewalls 22 and 23 on Figure 1), and 1.5 m long. The hingedly connected, movable panel (25 on Figure 1) was initially disposed at a 45 degree angle, and measured 1.5 m between its hinge and its free end. The overall height of the hopper was 2.95 m measured upwardly from the plane of the hopper bottom opening, which was initially closed by an hydraulically movable horizontal bottom gate. Although the hopper endwalls were vertical over their entire height, the referred to sidewalls were flared, at a 45 degree angle, over the uppermost 0.7 m of their respective heights. Swinging movement of the angular hopper bottom panel was provided by a reciprocatable hydraulic ram attached thereto, whose strokes produced angular movement, first a vertically projected distance of 100 mm in the upward direction measured at the free end of the panel, and then a vertical distance of 150 mm in the downward direction. The stroke rate was about 15 seconds per stroke, producing working pressure of about 170 kilograms per square centimeter (kg/cm2) on the material at the conclusion of the upward stroke. The hopper interior, excepting for the flared upper portion of the two sidewalls, was lined with UHMW polyethylene. The material had been found to have arched across the opening after an initial chunk of the material fell through when the horizontal bottom gate was first opened. However, subsequent repetitions stroking of the panel produced good flowability of the material through the hopper bottom opening. It is believed that a similar hopper and movable bottom panel arrangement, having dimensions which are five times those of this test hopper, will function in the same manner.

Such an enlarged hopper arrangement is exemplified by Figure 3 which illustrates an ocean-going bulk cargo carrying vessel, generally indicted by reference numeral 40, whose respective cargo holds 41 incorporate the present invention as a means for inducing discharging flow of essentially non-flowable bulk material such as nickel ore or synthetic gypsum (not shown), downwardly through their respective bottom openings 42 onto respective, longitudinally extending belt conveyors, generally indicated by the reference numerals 43. Each cargo hold 41 is defined by a longitudinal outboard bulkhead 44, a longitudinal inboard bulkhead 45, and respective transverse bulkheads 46, only one of which is illustrated in Figure 3 with respect to each hold 41. After removal of their hatch covers 47, respective holds 41 are loaded with bulk cargo via their top openings which are defined by the vertical hatch coamings 48 which extend around their perimeters.

Extending longitudinally between its transverse, end-defining bulkheads 46 each cargo hold 41 has opposite sloping bottom walls 49 and 50, respectively sloped at an angle from the horizontal of from 35 degrees to 75 degrees, preferably 45 degrees. Respective angular bottoms 49 and 50 have upper fixed sloping portions 49a, 50a, and lower movable sloping portions 49b, 50b whose respective lower, free ends are spaced laterally away from a short-height, vertical longitudinal bulkhead 53 located centrally of each hold 41, and define one side of each bottom opening 42. Bulkhead 53 defines the respective opposite sides of the opposed pair of bottom openings 42 in each hold 41, as shown. Pivotal movement of each of portions 49b, 50b about their respective hinges 51, 52 is by reciprocable hydraulic rams (not shown), similar to ram 27 on Figure 1 which moves panel 25 in that Figure. Fixed, center, vertical longitudinal bulkhead 53 also provides the preferred vertical wall opposite to each of movable panel portions 49b, 50b. Each of bottom openings 42 is closed by an openable gate (not shown), which is opened before the slow, reciprocal angular movements of the panels 49b, 50b are commenced. To provide economies in operation of the required hydraulic rams (not shown), respective pairs of panels 49b, 50b of the two cargo holds 41 should preferably work in alternately opposite directions. That is, with reference to Figure 3, as panel portions 49b are concurrently moved upwardly to their upper dotted line positions 49c, respective panel portions 50b are concurrently being moved downwardly to their lower dotted line positions 50d. Similarly, when panel portions 49b are being moved downwardly to their lower dotted line positions 49d, respective panel portions 50b are being moved upwardly to their upper dotted line positions 50c. Longitudinally adjacent panels should also be operated oppositely to each other. These opposite actions of alternate panels also augment the desired unbalanced condition of the cargo mass above longitudinal, short-height bulkheads 53 in each hold 41.

Thus, when cargo ship 40 is to be unloaded, longitudinal conveyors 43, one on either side of the centerline of the ship as shown in Figure 3, are started to convey the discharging cargo to the stern or other location on the ship for offloading. Movable gates (not shown) are opened beneath bottom openings 42, whereupon initial chunks of the non-flowable bulk cargo material may drop onto moving conveyors 43. Respective hydraulic rams (not shown) are then actuated to slowly and repeatedly arcuately move panels 49b, 50b in the previously described manner, whereupon the cargo in holds 41 drops substantially continuously through openings 42 onto conveyors 43 which move the discharging cargo material away from beneath holds 41 to the offloading location.

Referring now to Figures 4-8, there is illustrated an ocean-going cargo vessel or ship incorporating the presently preferred embodiment of the invention, generally indicated by reference numeral 60. Referring primarily to Figure 4, the vessel has a bow end 61, a stern end 62 in which the engine room 63 is located, and a bottom 64. Superstructure 65, including a bridge deck and bridge, ship's funnel, etc., rises above the main deck 66 of the ship. The vessel is intended to carry essentially non-flowable bulk cargo such as limonitic nickel ore or synthetic gypsum within some twenty cargo holds, each generally indicated by reference numeral 67. Each of the transversely adjacent cargo holds 67 extends in the athwartship direction from the longitudinal centerline 68 towards one side of the ship, as shown on Figure 6, and a extends a uniform distance between adjacent transverse bulkheads 69 in the fore and aft direction of the ship, as shown on Figure 4. The respective port and starboard holds on opposite sides of the longitudinal centerline 68 are aligned with each other in the longitudinal direction, as seen on Figure 4. The bulk cargo (not shown) is loaded into each hold 67 from above the main deck 66 (Figure 4) via respective open-topped cargo hatches indicated by hatch coamings 70 which surround the respective openings over each cargo hold 67. A hatch cover 70a on the hatch coaming 70 covers and closes each hatch after the cargo has been loaded. The ship is a self-unloading type in which, as will be understood from the conventional "W"-shape of each transversely adjacent pair of cargo holds as seen on Figure 6, each hold empties its cargo via a bottom opening 81 (Figures 7 and 8) onto a longitudinally extending, moving conveyor 73 which, as seen on Figures 4 and 5, conveys the material aft to deposit it on an unloading chute 74.

With particular reference to Figures 6 and 7, each cargo hold 67 in any transversely adjacent pair thereof is defined by a vertical bulkhead on longitudinal centerline 68 of the ship which provides its inner vertical sidewall 67a; an opposite, outboard vertical sidewall 67b; oppositely disposed longitudinally spaced apart transverse bulkheads 69 of the ship, delineating the respective endwalls of each hold; and inclined fixed bottom walls 67c and 67d which slope downwardly and laterally towards a plurality of longitudinally aligned, box-like hopper chutes 80. Chutes 80 define the plurality of bottom discharge openings 81 in each cargo hold 67.

As illustrated on Figures 7 and 8, within each of hopper chutes 80, between its endwalls 84, 85, is mounted a movable bottom flap or panel 82 whose upper end 82a is pivotally mounted on one of vertical chute sidewalls 80a by a horizontal hinge 83 which extends between chute endwalls 84, 85 (Figure 7). It will be noted that chute endwalls 84, 85 are oriented at right angles to endwalls 69 of cargo hold 67, although it will be understood that chutes 80 might be oriented with their endwalls paralleling the cargo hold sidewalls 67a, 67c, if desired. The free end 82b of each panel 82 is laterally spaced way from opposite vertical side wall 80b of the chute, to define bottom opening 81.

Reciprocal pivotal movement of panel 82 between its upper position (dotted line 82c) and its lower position (dotted line 82d) is effected using one or more hydraulic rams 86, only one of which is shown. The ram 86 is pivotally connected at one of its ends 86a to panel 82 and at the other of its ends 86b to a fixed support member 88 on the vessel 60. The bottom discharge opening 81 is closed by an hydraulically actuated bottom closing gate 87, which is movable horizontally as shown by the arrow on Figure 8, between its dashed-line closed position 87a and its opened position indicated by solid lines 87.

Each chute 80 is supported by support members 88, and belt conveyor 73 therebelow is supported by a roller frame 89 which mounts conveyor rollers 73a which, in turn, carry moving belt 73b. As seen on Figures 4 and 5, each of parallel cargo discharge conveyors 73 extends beneath all of longitudinally aligned holds 67 along one side of the ship, to collect bulk cargo discharged from any of them and transport it towards stern 62, through a conveyor tunnel 73c, to discharge over the stern via the associated one of a pair of retractable and extendable cargo slides 74. The bulk material tumbles down slides 74 and is discharged overboard, to be received on a cross-conveyor 75 which is mounted on a float 76 extending outwardly from a pier of dock 77 to which ship 60 is moored. Float 76 is swingable out from dock 77 as indicated by dotted lines and arrows on Figure 5. Although other arrangements might be employed, float 76 is swingable back towards dock 77 to facilitate maneuvering of ship 60 when docking or moving away from dock 77. The arrowheads on Figure 5 illustrate the movement towards dock 77 of cross-conveyor 75, which may be inclined upwardly, to discharge the cargo therefrom into an open-bottomed hopper 75a which, in turn, feeds it on to a dockside continuation of the cross conveyer, as shown. The cargo is thus moved inland to a storage or processing location (not shown).

Each cargo hold 67 is preferably provided with a plurality of discharge chutes 80 at its bottom. In the illustrated embodiment, each cargo hold has six such chutes, as shown on Figures 5 and 7. The chutes 80 are arranged in longitudinally aligned pairs, their movable bottom panels 82 preferably facing in the fore and aft direction of the ship 60, above one of conveyors 73 onto which the chutes will discharge the cargo material. Between each pair and across angular bottom wall 67d within any hold 67 there is preferably provided a short height, transverse vertical partition or apron 90. Longitudinally extending, vertical skirts 91 (Figure 7) depend from the respective vertical endwalls 84, 85 of the aligned chutes 80 downwardly to and along the respective sides of each belt conveyor 73 to avoid spillage of the material being discharged on to the conveyors. As seen on Figure 6 the sloping inboard bottom wall 67d in each hold 67 is disposed at an angle of from about 35 degrees to 45 degrees to the horizontal, whereas the outboard bottom wall 67d has an inclination of about 70 degrees or 75 degrees.

With reference to any pair of longitudinally aligned chutes 80, as illustrated on Figure 7, their respective movable bottom panels 82 are preferably operated synchronously but oppositely with respect to each other, with the slow, reciprocal angular motion as previously described, by respective hydraulic rams 86 (Figure 8). That is, when panel 82 of, say, forwardmost chute 80 of the pair is moving upwardly towards its uppermost position 82c (Fig. 8), panel 82 of the other chute 80 of the pair is moving downwardly towards its lowermost position 82d (Figure 8), and vice versa. Thus, while upward unbalanced pressure in the cargo material is being generated in one chute, a releasing of pressure thereon and creation of a temporary void space therebelow is occurring in the other. It is believed that this synchronized, oppositely symmetrical motion of the two panels in the pair will generate additional internal unbalanced forces within all of the mass of material within the hold 67, especially in the mass situated immediately above both of the chutes in the pair. These unbalanced forces will assist in producing the shearing and tumbling action of the cargo material to cause its flow and discharge through chute openings 81, as previously described. The desired creation of unbalanced forces within the cargo mass during the panel movements is believed to be further enhanced by the unsymmetrical angular dispositions of opposing sloped bottom wall portions 67c and 67d of the cargo hold, and by the presence of short-height transverse vertical aprons 90 between chute pairs.

In a modified form of the invention illustrated on Figure 9 and explained with references to Figures 10A and 10B, the movement of the nickel ore, synthetic gypsum, or other essentially non-flowable bulk cargo towards bottom discharge chutes 80 within each cargo hold 67 is augmented by a scraper panel 100 which is initially upright against and along inner vertical wall 67a of each hold 67. Panels 100 within each of any pair of transversely adjacent holds 67 are worked together by the vertical translatory movement of a longitudinally extending hinge 101 to which their respective upper longitudinal edges 100a, are connected. Hinge 101 extends along the longitudinal centerline 68 of the ship 60, as shown in Figure 9. This concurrent action of pair of panels 100 is effected by one or more hydraulic jacks 102 whose cylinder 102a rests on inner bottom 64a of ship 60 and whose ram 102b is attached to hinge 101 between two scraper panels. Preferably two such jacks

102 are employed for each pair of panels 100 attached at the one-third points along the length of the hinge 101, which length corresponds to the distance between the respective transverse bulkheads 69 which define the forward and rearward endwalls of a pair of cargo holds 67.

Vertical downward movement of jack ram 102b pulls hinge 101 downwardly, with translatory movement, to cause panels 100 to tilt as well as to move downwardly so that their lower edges 100b spread laterally, respectively moving downwardly and outwardly on and along respective sloping bottoms 67d of the holds 67 as the panels tilt, as indicated by dotted lines on Figure 9. Vertical upward movement of jack ram 102b returns panels 100 to their upright positions against respective inner vertical walls 67a of holds 67. The desired vertical reciprocal movement is controlled by an operator to move the cargo laterally towards chutes 80 at the bottoms of bottom walls 67d. Respective ends of longitudinal hinge 101 move within and are guided by vertical slides (not shown) attached to each transverse bulkhead 69, and rollers (not shown) may be attached along the lower ends 100b of the panels.

This lateral movement of the cargo is promoted in a manner somewhat similar to that provided by angular panels 82 within chutes 80. That is, with particular reference to Figures 10A and 108, the downward movement of each panel 100 (Figure 10A) generates and establishes internal unbalanced pressures and some void spaces V (above hinge 101) within the cargo mass M, compacting the lowermost portion D of the cargo as it does so, and the upward movement of each panel 100 (Fig. 10B) momentarily creates void spaces V beneath the mass as the panel retracts angularly. The result is that the established potential energy of the mass over void spaces V and the unbalanced forces within cargo M cause the mass of material to shear and collapse towards chutes 80. The operator may stop the downward movement of panels 100 as resistance increases, and raise them to permit such tumbling action as chutes 80 empty more and more of the cargo through discharge openings 81. Of course, the limit of the downward movement is that at which the panels 100 would be extended into parallel relationship on and along the bottomwalls 67d. It will be noted that gravity assists the falling movement of cargo mass M downwardly along the angled bottoms 67d, and that the amount of force required to be imparted by panels 100 is less than what one might initially expect. To accelerate collapsing of the moving mass M over chutes 80, a plurality of laterally directed water jet or air jet orifices 103 may be provided along the length of each bottom wall 67d at points laterally spaced away from, but close to chutes 80, preferably on the inboard sides, as indicated on Figure 9. Jets of either air or water at high pressures, emitted either continuously or intermittently through orifices 103 induce breaking off along the lower edges of the compacted masses of cargo being moved outwardly by panels 100 towards the chutes. Further, the outwardly facing surfaces of each panel 100 may be provided with a 1/8" thick sheet of UHMW polyethylene or similar friction-reducing material to assist the sliding of cargo masses M therealong. It will be noted that the creation of the desired unbalanced internal forces within the cargo mass in each hold is enhanced by the cross-directional disposition of transversely facing movable panels 100 relative to longitudinally facing movable panels 82 within chutes 80, and the resulting changes in the directions of exerted pressures within the cargo mass.

An alternative form of these augmenting panels is illustrated on Figure 11. Two, vertically upright panels 105 are movable laterally and reciprocally in the transverse direction while retaining their upright dispositions as their lower edges 105b slide along respective sloping bottom walls 67d of cargo holds 67, their concurrent movement being induced by one or more hydraulically actuated jacks 106 mounted vertically along the ship's longitudinal centerline 68, as shown. The upper end of ram 106a of each jack is pivotally connected at pivot point 108a to one link rod 107a of a pantograph mounting 107 of each panel 105, as indicated on Figure 11. The cylinder portion 106b of each vertical jack 106 is mounted in fixed position on centerline 68 as shown. The lower end of each link rod 107a is pivotally connected, as at 108b, to lower edge 105b of its associated panel 105, and the other link rod 107b of each pantograph 107 is pivotally connected at each of its ends to extend between panel upper edge 105a and fixed location 109 at the base of jack cylinder 106b. Thus, each link rod 107b moves arcuately about fixed pivot point 109 as its upper end pivots on laterally and downwardly moving vertical panel 105 during the vertical movement of jack ram 106a, and lower edge 105b of each panel 105 moves along and guided by sloping bottom 67d during the movement of jack 106.

Respective guide rails (not shown) for the ends of the panels 105 are attached to vertical transverse bulkheads 69 at either end of each cargo hold 67, and the outboard surfaces of each panel 105 are preferably coated with a sheet of UHMW polyethylene or similar friction-reducing material.

As chutes 80 operate as previously described to discharge cargo material onto respective conveyers 73, jacks 106 are operated in downward direction to move vertical panels 105 with translatory movement, provided by pantograph linkages 107a, 107b, in outboard direction to urge the cargo material outboard to feed it, in substantially continuous manner, over chutes 80 disposed along the outboard sides of cargo holds 67, as will be understood from Figure 11. Movement of the cargo mass along downwardly sloping bottom 67d is assisted by gravity, and the breaking off of the material over the chutes 80 may be assisted by the operation of air or water jets 103, as in the embodiment of Figure 9.

Further, and as illustrated on Figure 12, lower edge 105b of each panel 105 may have a panel skid 110 pivotally attached thereto, to assist the movement of the mass towards chutes 80. The width of panel skid 110 is about one-third of that of downwardly sloping bottomwall 67d on which it rests. Air or water jet orifices 103 may also be employed, if desired, for the previously described purpose. Preferably, the extent of movement is such that the maximum distance each panel skid 110 moves along bottomwall 67d is about one-third the width of the latter in the downward direction. The movement of panel skid 110 is guided by cradles 111 in which steel balls (not shown) are disposed. The upwardly facing surfaces of panel skids 110, as well as the surfaces of the panels 105, may be coated with friction-reducing material to aid the movement of the cargo material off the panel skis 110 and into chutes 80 as the unloading proceeds.

If desired, a panel skid such as panel skid 110 may be hingedly attached along lower end edge 100b of each panel 100 on the Figure 9 embodiment, for the same purpose.

It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Claims

1. A method of promoting discharge of essentially non-flowable material through a bottom opening of a container within which said material is stored, comprising the steps of:

(a) slowly applying pressure to upwardly press at least a lower portion of mass of said material; and (b) thereafter, releasing said pressure, whereby portions of said material fall through said bottom opening.

2. A method, as defined in Claim 1, wherein said bottom opening is substantially horizontally disposed and said steps include:

(a) slowing pressing an angularly disposed panel upwardly and angularly a distance into said material from a location on one side of said bottom opening and towards a substantially upright wall extending upwardly substantially from the opposite side of said bottom opening; and

(b) thereafter, releasing said pressure by slowly moving said panel in opposite direction a distance away from said material, whereby portions of said material fall through said bottom opening.

3. A method, as defined in Claim 1, wherein: said pressing is applied from substantially adjacent to said bottom opening.

4. A method, as defined in Claim 2, wherein: said angularly disposed panel has a horizontally disposed free lower end edge substantially defining said one side of said bottom opening, and said panel is mounted for pivotal movement about an opposite, horizontally disposed upper end edge thereof, whereby said pressing comprises pivoting said panel about its said upper end edge to move said panel free end said distances into and away from said material.

5. A method, as defined in Claim 1, wherein: said pressing and releasing steps are performed slowly and repetitively in substantially continuous manner.

6. A method, as defined in Claim 5, wherein: said pressing and releasing steps are performed at a rate of substantially two (2) cycles per minute.

7. A method, as defined in Claim 4, wherein: said panel is initially disposed at an angle of between about 35 degrees and about 60 degrees from the horizontal, and said pressing and releasing steps are performed by pivoting said panel about its said upper end edge first upwardly over an arc of about 15 degrees from its said initial angular disposition to an upper position thereof and then downwardly over an arc of about 30 degrees from its said upper position to a lower position thereof, and thereafter repetitively between said upper and lower positions.

8. A method, as defined in Claim 7, wherein: said angle of initial disposition is substantially 45 degrees.

9. A method, as defined in Claim 4, further comprising: slowly pressing an initially vertical second panel against said material to move it in lateral and downward direction towards the first said panel along an angular bottomwall of said container disposed adjacent to and above the first said panel.

10. A method, as defined in Claim 9, wherein: said lateral pressing additionally comprises: slowly wedging the lower edge of said second panel into and beneath said material from said lateral direction, said second panel lower edge engaging and being guided by said angular bottomwall during said wedging movement, and thereafter releasing said wedging of said second panel by reversing the direction of its said wedging movement to form a temporary void space beneath said material into which portions of said material fall.

11. A method of offloading essentially non- flowable material from a plurality of aligned cargo holds within which it is stored on a bulk cargo carrying ship, said cargo holds being spaced above longitudinally extending conveyor means for receiving said material as it is discharged from each of said cargo holds through respective horizontally disposed bottom openings of each hold and for carrying said discharged material to an offloading location on said ship, comprising the steps of:

(a) starting the offloading movement of said conveyor means, opening said bottom openings of said plurality of cargo holds;

(b) slowly pivoting at least one angularly disposed panel in each said cargo hold, each panel having a horizontally disposed free lower end edge adjacent to one side of said bottom opening and a hingedly mounted upper end edge spaced away from said bottom opening, a radial distance of substantially 15 degrees upwardly to press said material upwardly and towards a substantially upright bulkhead extending upwardly substantially from the opposite side of said bottom opening; (c) then slowly moving said panels in opposite direction: and (d) slowly repeating said pressing and opposite movements of said panels, whereby said material in said plurality of cargo holds falls substantially continuously through said bottom openings onto said moving conveyor means.

12. A method, as defined in Claim 11, wherein: said pressing and opposite movements of said panels are performed alternately and oppositely with respect to each other.

13. A container for storing and unloading therefrom essentially non-flowable material in bulk, comprising:

(a) a pair of spaced apart opposite endwalls, a pair of spaced apart opposite sidewalls respectively extending between said pair of endwalls, and container bottom means comprising means defining a substantially horizontally disposed bottom opening within the area defined by said endwalls and sidewalls for unloading said material therethrough;

(b) an openable bottom gate normally closing said bottom opening; (c) material discharging means comprising an angularly disposed discharging panel having a substantially horizontal lower end edge normally positioned adjacent to one side of said bottom opening above said bottom gate and an upper end edge mounted for pivotal movement at a location spaced upwardly and laterally away from said one side of said bottom opening, a wall extending upwardly substantially from the side of said bottom opening which is opposite to said one side thereof; and (d) means for pivoting said panel slowly upwardly to move its said fee end edge into the weight of said material when within said container and slowly downwardly to return its said free end edge at least to its said normal position.

14. A container, as defined in Claim 13, wherein: said pivoting means is further adapted to move said discharging panel downwardly below its said normal position.

15. A container, as defined in Claim 13, wherein: said upwardly extending wall is substantially vertical.

16. A container, as defined in Claim 15, wherein: said vertical wall has friction-reducing material disposed thereon.

17. A container, as defined in Claim 14, wherein: said discharging panel in its said normal position is disposed at an angle of from substantially 35 degrees to substantially 60 degrees to the horizontal, and said pivoting means is adapted to move said panel upwardly a radial distance of up to substantially 15 degrees above said normal position and downwardly a radial distance of up to substantially 15 degrees below said normal position.

18. A container, as defined in Claim 17, wherein: said angle is substantially 45 degrees.

19. A container, as defined in Claim 17, wherein: said pivoting means is adapted to so move said panel at a rate of substantially two cycles per minutes.

20. A container, as defined in Claim 41, wherein: said upwardly extending wall is one of said pair of container sidewalls, and said discharging panel upper end edge is mounted for pivotal movement on the opposite one of said pair of container sidewalls.

21. A container, as defined in Claim 14, wherein: said container bottom means further comprises an angularly disposed fixed container bottom portion extending angularly upward from said discharging panel upper end edge to one of said pair of container sidewalls, said panel upper end edge being pivotally mounted on said fixed bottom portion.

22. A container, as defined in Claim 21, wherein: said container is the cargo hold of a ship, said endwalls comprising respective transverse bulkheads of said ship, and said ship having movable conveyor means thereon beneath said container bottom opening for receiving said material as it is unloaded through said bottom opening and conveying said material to an offloading location on said ship.

23. A container for storing and unloading therefrom essentially non-flowable material in bulk, comprising:

(a) a pair of spaced apart opposite endwalls, a pair of spaced apart opposite sidewalls respectively extending between said pair of endwalls, and container bottom means comprising an angularly disposed container bottom sloping downwardly from one of said sidewalls towards the opposite one of said sidewalls and having a lower end, and at least one material discharging chute attached to and extending below said fixed bottom portion lower end; (b) said chute comprising a pair of spaced apart vertical endwalls having respective horizontally aligned lower edges, at least one substantially upright sidewall extending between said vertical endwalls and having a lower edge horizontally aligned with said chute endwall lower edges;

(c) an angularly disposed and movable discharging panel extending between said chute endwalls and having a substantially horizontal lower free end edge normally horizontally aligned with said chute endwall lower edges and spaced laterally away from said chute sidewall lower edge thereby together forming a horizontal bottom opening of said chute and said container;

(d) an openable bottom gate normally closing said bottom opening;

(e) said discharging panel further having an upper end edge which is pivotally mounted on hinge means extending substantially between said chute endwalls; and (f) means for imparting slow, reciprocal pivotal movement to said discharging panel to move its said lower free end edge upwardly into the weight of said material when within said chute and downwardly to its said position horizontally aligned with said chute sidewall and endwall lower edges.

24. A container, as defined in Claim 23, wherein: said chute endwalls are oriented substantially parallel to said opposite sidewalls of said container, one of said chute endwalls being attached to said container bottom lower end.

25. A container, as defined in Claim 23, wherein: said container bottom means comprises a pair of said material discharging chutes each having their said chute endwalls oriented substantially parallel to said opposite sidewalls of said container, one of said endwalls of each chute being attached to said container bottom lower end, and which further comprises a substantially vertical apron extending transversely of and between the chutes which constitute said pair thereof; said apron extending upwardly within said container.

26. A container, as defined in Claim 25, wherein: said means for imparting movement to said movable discharging panels of the chutes constituting said pair thereof is adapted to move said panels in opposite directions with respect to each other.

27. A container, as defined in Claim 23, wherein said container bottom means f rther comprises: at least one fluid jet orifice disposed substantially on said container bottom adjacent to its said lower end for introducing fluid under pressure into said container adjacent to each said chute.

28. A container, as defined in Claim 23, wherein: (a) said container is the cargo hold of a ship; (b) said pair of container endwalls comprises respective transverse bulkheads of said ship, one of said container sidewalls comprises a center longitudinal bulkhead of said ship; and

(c) said container bottom slopes downwardly from said longitudinal bulkhead: and said container further comprises:

(d) a vertical second panel initially disposed substantially against said center longitudinal bulkhead and having a lower end edge engaging said container bottom wall; and

(e) means mounting said second panel for lateral and downward movement on said sloping container bottom with its said lower end edge engaging the latter to move said material, when within said hold, towards said at least one chute.

29. A container, as defined in Claim 28, wherein: said second panel mounting means comprises: a pantograph linkage arrangement connected to said second panel, and an hydraulic jack having means providing reciprocal vertical movement thereof, said pantograph linkage also being connected to said jack whereby said movement of said jack induces translatory lateral and downward movement of said second panel.

30. A container, as defined in Claim 29, further comprising: a panel skid in substantially slidable engagement on said sloping container bottom and connected to said lower end edge of said second panel, said panel skid having width extending part way down said sloping bottom wall.

31. A container according to claim 28, wherein: said second panel has an upper end edge, and said second panel mounting means comprises horizontal hinge means extending along said second panel upper end edge, and vertical hydraulic jack means connected to said hinge means for moving said second panel hinge means downwardly and upwardly with translatory movement, whereby said second panel also tilts during said movement of its said lower end edge downwardly on said sloping container bottom.