AU2002301872B2 - Shipping Container for Powdered Material - Google Patents

Description

1 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: QR Limited Actual Inventors: Martin Dyrbus Paul Anthony Mullins Kelvin Bruce Heazlewood Address for Service: CULLEN & CO. Patent & Trade Mark Attorneys 239 George Street Brisbane QId 4000 Invention Title: Shipping Container for Powdered Material The following statement is a full description of the invention, including the best method of performing it, known to us: 2 TECHNICAL FIELD The invention described herein relates to shipping containers used for the transport of materials that are in the form of a fine powder. In particular, the invention relates to shipping containers that meet ISO specifications. The invention also relates to a method of 5 transporting powdered materials using the subject containers. BACKGROUND ART It is frequently necessary to transport materials that are of a powdered nature from the site of manufacture to the site of distribution, storage or use. A difficulty with powdered 10 materials, particular fine powders such as cement, is that the material settles during transportation. Settling of cement can be to the extent that the material becomes rock-like. Pressurised air is commonly used to discharge settled powdered material from a shipping container. Air lances, for example, can be inserted into the settled mass. On supplying air of sufficient pressure to the mass via the lance, at least a portion of the 15 material is fluidised allowing it to be pumped from the container. Other ways of fluidising settled material include air mats and vibra pads. Pressure vessels for the shipping of powdered material are available. However, such containers have the following disadvantages: * they are heavier per unit volume than standard shipping containers; 20 * they are more expensive per unit volume than standard shipping containers; and . if made to fit within ISO shipping container dimensions have reduced capacities relative to a standard shipping container. Shipping containers are known that are constructed to International Convention for Safe Containers (CSC) standards that can be used for transporting powdered material. 25 Special adaptations are required to remove the material from the container, particularly if settled, without loss thereof to the environment. (Avoidance of loss of material to the environment precludes the simple dumping of the container contents into a hopper.) A variety of methods have been described for removal of powdered material from a shipping container. For example, the container described in GB 2 219 784 A has a false 30 floor therein through which low or medium pressure air is pumped to fluidise the material for evacuation through the floor. In GB 2 116 938 A there is similarly described a shipping container in which the floor is covered by an air-permeable mat. Shipping containers of the type described in the previous paragraph overcome at least the weight disadvantage of pressure vessel-type shipping containers but of 3 themselves have limitations. Specifically, evacuation rates with some particulate materials such as cement are low and evacuation is not always complete. Efficient shipping of powdered materials demands complete evacuation of the container used for the shipping of the material. 5 There is therefore a need for a shipping container that can be used for the efficient transportation of bulk quantities of powdered materials but which does not require use of a pressure vessel to contain the material. The object of the invention is thus to provide a shipping container for powdered material which: . is of minimum tare weight; and 10 e permits complete evacuation of the container contents. SUMMARY OF THE INVENTION In a first embodiment of the invention, there is provided a shipping container for powdered material, said container being of a generally rectangular shape and having a 15 floor, a roof, side walls, a front end wall and a rear end wall, wherein said rear end wall comprises a plurality of outwardly sloped panels which form an oblique pyramid whose apex is proximal said floor and is mid-way between said side walls of said container, and wherein said container further comprises: a sealable inlet port in said roof; 20 a sealable outlet port at said apex of said pyramid; a plurality of air mats adjacent said outlet port on said floor of said container; a plurality of vibra pads on the lower portion of said rear end wall of said container; at least one air lance in said outlet port; at least one vibrator in external contact with said floor of said container; 25 a high pressure system for independently supplying air to said at least one air lance and said at least one vibrator; and a low pressure system for supplying air to said vibra pads and said plurality of air mats. In a second embodiment, the invention provides a method of transporting bulk 30 powdered material to a delivery site, the method comprising the steps of: a) charging a shipping container according to the first embodiment with said powdered material; b) moving said container to said delivery site; 4 c) connecting said container outlet port via a hose to a pneumatic conveying vessel for transferring said powdered material to a holding silo; d) fluidising settled powdered material adjacent said outlet port by supplying air to said air mats, vibra pads and at least one air lance while elevating the front end of said 5 container; e) transferring fluidised powder from said container to said silo; and f) activating said at least one vibrator towards completion of discharge of said powdered material. Other embodiments of the invention will become apparent from the detailed 10 description of the invention which follows. Exemplification of the invention will be aided by reference to the accompanying drawings to be briefly described hereafter. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a shipping container according to the invention. 15 Figure 2 is a view from above of the shipping container shown in Figure 1. Figure 3 is a view of the front end of the shipping container shown in Figure 1. Figure 4 is a view of the rear end of the shipping container shown in Figure 1. Figure 5 is a cross-sectional view at A-A of Figure 1. Figure 6 is a partial enlarged cross-sectional view at B-B of Figure 2. 20 DETAILED DESCRIPTION OF THE INVENTION The term "powdered material" as used herein includes, but is not limited to, cement flour, flyash, magnetite, and prilled or powdered sulfer. The term "low pressure" denotes a pressure of typically not more than about 100 25 kPa. The term "high pressure" denotes a pressure of 550 to 690 kPa. Any reference to an ISO shipping container is a reference to a container having approximate dimensions of 6.1 m in length by 2.5 m in width by 2.7 m in height as will be known to those of skill in the art. 30 The term "comprise" and variants of the terry such as "comprises" or "comprising" are used herein to denote the inclusion of a stated integer or stated integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive interpretation of the term is required.

5 With reference to the first embodiment of the invention, as defined above the shipping container is of generally rectangular shape. Preferably, the shipping container of the invention has the same external dimensions as a standard ISO shipping container. However, it will be appreciated that the container can be of any size. 5 A shipping container according to the invention typically includes other features of standard ISO shipping containers such as top and bottom corner fittings and fork lift pockets on the bottom thereof. However, to prevent adherence of material to the walls of a container the inside surfaces are smooth. There are furthermore advantageously included at the junctions of the walls and floor deflector plates to smooth out these junctions. The 10 deflector plates are preferably concave with respect to the interior of the container. With regard to the inlet port, this can be any suitable hatch or arrangement through which the powdered material can be admitted into the container. Sealing can be by any of the means known in the art and include merely providing a resilient material at the periphery of a hatch which contacts the roof at the opening therein covered by the hatch. Valves can 15 also be used as the sealing means in an inlet port configured therefor. The outlet port is typically a discharge tube terminating in a fitting adapted for connection to a complementary fitting on any hose use for evacuating the contents of the container. Sealing of the port is by any suitable valve. Preferably, sealing is by way of a pneumatically operated butterfly valve. 20 With regard to the air mats, these are obtained from bulk air mat material which will be known to those of skill in the art. A section of air mat of an appropriate size is mounted into a frame which can be fixed to the container floor and an air supply line connected thereto. The air mats typically are arranged in a vee pointing toward the outlet port. Air mats can also be fitted to the internal surface of the rear end wall adjacent the outlet port. 25 Containers typically comprise 10 to 25 air mats. Containers typically have from 3 to 7 vibra pads. A preferred number of pads is 5 positioned as will be detailed below. The vibrator can be any of the vibrators known to those of skill in the art including ball, sonic and hammer vibrators. Preferably, containers according to the invention include 30 two vibrators, both lying on the centre-line of the floor with one positioned at about the centre of the container and the second in between the first vibrator and the rear end wall. With regard to the at least one air lance, where sealing of the outlet port is by way of a valve, there are preferably two such lances, one on each side of the valve. This ensures that the powder remains fluidised during passage through the outlet port.

6 The high pressure air system comprises individual systems of pipes for each type of component supplied by the overall system. The individual piping systems have inlet connectors and non-return valves that are advantageously duplicated on each side of a container. This duplication allows greater flexibility in connection to a supply of air. 5 The low pressure air system, as indicated above, is for supply of air to the air mats. The supply is advantageously via a header. Shipping container according to the invention can further include a pressure relief valve in the roof thereof. An access door can also be provided in the front wall. However, it will be appreciated that a container according to the invention does not include the full width 10 or full height doors of a standard ISO shipping container. Shipping containers according to the invention are typically fabricated from a metals material. A preferred material is steel. Turning to the second embodiment of the invention, as indicated above the subject containers can be conveniently used for the transportation of bulk powdered material. With 15 the subject containers up to 32 tonnes gross can be transported per container of a typical tare weight of 4 tonnes. With regard to the steps of the method, charging the container can be by any suitable means including pumping or gravity feed from a silo. With materials such as cement and noxious or dangerous materials in particular, loading is advantageously by way 20 of a chute that is sealably connected to the inlet port of the container to prevent spillage of the material. Moving the container (step (b)), as with standard shipping containers, can be by air, road, rail or sea with the container carried within an airplane, or mounted to a motor vehicle trailer or tray, railway wagon or ship, respectively. A plurality of containers can be moved 25 by any of these means. In step (c), connection of the outlet port to the hose is typically by way of male and female components that can be clipped or clamped together but can be disengaged on completion of evacuation of the container. A preferred connection is by what is referred to in the art as a "Kamlok". 30 Step (d) of the method will be explained in greater detail below. During evacuation, the container is tilted so that the floor is between an angle of 400 and 60". This tilting causes material to flow towards the outlet port which is lowermost. A preferred angle is 60".

7 Regarding the final step of the method, pump-out of the container can be at a rate as great as 60 tonnes per hour. Having broadly described the invention, a shipping container and method of use will now be exemplified with reference to the accompanying drawings. 5 Referring now to Figures 1 to 4, there is shown container 1 comprising floor 2, roof 3, side walls 4 and 5, front end wall 6 and rear end wall 7. Container 1 has overall dimensions of: length, 6.1 m; width, 2.5 m; and height 2.7 m. The container has at each corner a fitting for receiving hooks, shackles or twistlocks. One such corner fitting is item 8. The container further has frame members at its edges, one of which is item 9 of Figure 1 and cross 10 members, one of which is item 10 of that figure. Pockets 11 and 12 are provided in the sides of the container for receiving the tines of a fork lift for lifting the container with such equipment. The components of container 1 referred to above are fabricated from steel. With reference to roof 3 (see Figures 1 and 2), this includes an inlet port 13 in the 15 form of a lockable hatch and a combined pressure relief valve/vent. The last-mentioned item is suitably a Model SSM25OK2 with mounting spigot No. SFU250EI available from Kockums Bulk Services Pty Ltd of 139 Bamfield Road, Heidelberg West, Victoria. Front end wall 6 (see Figure 3) includes an access door 15 which has on the inside surface at its periphery a rubber seal so that when locked in the closed position contents 20 cannot be lost via the access door opening. Access door 15 plays no part in container filling and discharge and is only used for inspection of an empty container. Rear end wall 7 will now be described with reference to Figures 1 and 4. Wall 7 comprises a number of angled plates, three of which are items 16, 17 and 18. These plates, in combination with portion of floor 2, form an oblique pyramid whose apex lies close 25 to the plane of floor 2. An outlet port 19 in the form of a 200 mm ID discharge tube lies at the apex of the oblique pyramid. Outlet port 19 will be referred to in greater detail below. Since the panels forming end wall 7 are set back from the extremity 20 of container 1 (see Figure 1), braces are provided between frame members. Two such brace members are items 21 and 22 of Figures 1 and 4, respectively. The space between frame members 30 and the panels of end wall 7 is used for other container components. Panels are also provided for protecting and/or containing components. For example, items 23 to 25 of Figure 4 are covers for the discharge port. The internal and other detail of the container of Figures 1 to 4 can be appreciated from Figure 5 which is a cross-sectional view in plan at the axis of the discharge tube 8 forming outlet port 19. In Figure 5, there can be seen that there are eleven air mats arranged in a vee with the point of the vee at outlet port 19. One of the air mats is item 26 of the figure. Another two groups 27 and 28 of four air mats each are mounted at the base of each of panels 18 and 16, respectively, of end wall 7. Each air mat of the foregoing 5 groups of air mats is a 240 by 180 mm section of T5-5 mm Polyester Air Slide matting available from Filtration Fabrics Pty Ltd of 175 Elliot Road, Banyo, Queensland. Container 1 also includes five vibra pads, one each on panels 16, 17 and 18 mounted 200 mm in from the outlet port and 382 mm up from the floor (not visible in Figure 5) and two, 29 and 30, mounted on floor 2. There are also two ball vibrators mounted 10 beneath floor 2, one in the position indicated by item 31 and the other in the position indicated by item 32. Outlet port 19 includes a pneumatically operated butterfly valve 33 (Keystone AR2 CYE2 1.75 uc as 2129E). Port 19 also has an air lance 34 at the inlet thereto and a second air lance 35 between valve 33 and a camlok 36 at the distal end of the port. 15 Duplicate air supply systems 37 and 38 can also be seen in Figure 5. Figure 6 shows detail of a junction between wall 5 and floor 2. Deflector plate 39 which is at 450 to the wall and floor, can be seen to smooth out the junction. Corner fitting 40 and frame member 41 can also be seen in this figure as well as portion of a crossmember 42 at the front edge of the container. 20 The deflector plate at the junction of end wall 7 and floor 2 (see Figure 1) in the vicinity of the outlet port is advantageously at 30* to the floor. Having described in detail a container according to the invention, its use in the method of the invention will now be illustrated. The detailed description will be given in respect of cement as the powdered material for transportation. 25 An empty container 1 is charged with cement via hatch 13 by gravity feed from a supply silo. Typically 28 tonne is loaded per container. The filled container is then transferred, if necessary, to a transportation means such as a motor vehicle tray or trailer, a railway wagon, or to the hold or deck of a ship. The container is then carried to the delivery site. 30 At the delivery site, a hose is connected to outlet port 19 via camlok 36. The hose feeds a pneumatic conveying vessel (such equipment being available, for example, from Kockums Pty Ltd: see above) which in turn feeds a holding silo. Low and high pressure air supplies are then connected as appropriate to the lines comprising the container air systems. To facilitate correct connection of an external supply line to a container air line, 9 the various container lines are advantageously differently sized. Container evacuation is initiated by fluidising cement (necessary since the cement settles during transportation) by supplying air to air lances 34 and 35, the air mats (ie, the group including air mat 26 and groups 27 and 28) and the vibra pads. Simultaneously, butterfly valve 33 is opened and the 5 container tilted to an angle of 600. This is done by pivotally securing the rear end of the container at point 43 and jacking or lifting the front end of the container. Fluidised cement is drawn out of the container by the evacuation system described above. The tilting of the container ensures that solidified cement away from the outlet port moves thereto where it is fluidised by the air lances, air mats and vibra pads. 10 Evacuation takes of the order of 30 minutes. During roughly the last 5 minutes of evacuation, the vibrators are activated to ensure that any cement residue on the floor of the container is dislodged. Complete evacuation is determined by comparing the amount of cement transferred to the holding silo with the amount of cement originally loaded into the container. 15 In the event of excessive pressure build-up in the container, pressure relief valve 14 operates to equalise the pressure variation. The container evacuation procedure can be computer controlled to minimise operator input. The computer also logs the amount of cement delivered by each container. It will be appreciated that many changes can be made to the shipping container and 20 method of use exemplified above without departing from the broad ambit and scope of the invention. Any reference to publications cited herein is not an admission that the disclosures constitute common general knowledge in Australia.

Claims (20)

1. A shipping container for powdered material, said container being of a generally rectangular shape and having a floor, a roof, side walls, a front end wall and a rear end wall, wherein said rear end wall comprises a plurality of outwardly sloped panels which form an 5 oblique pyramid whose apex is proximal said floor and is mid-way between said side walls of said container, and wherein said container further comprises: a sealable inlet port in said roof; a sealable outlet port at said apex of said pyramid; a plurality of air mats adjacent said outlet port on said floor of said container; 10 a plurality of vibra pads on the lower portion of said rear end wall of said container; at least one air lance in said outlet port; at least one vibrator in external contact with said floor of said container; a high pressure system for independently supplying air to said at least one air lance and said at least one vibrator; and 15 a low pressure system for supplying air to said vibra pads and said plurality of air mats.

2. The shipping container according to claim 1, wherein said inlet port comprises a hatch.

3. The shipping container according to claim 1 or claim 2, wherein said outlet port 20 comprises a discharge tube having therein a pneumatically operated butterfly value.

4. The shipping container according to any one of the preceding claims, wherein the distal end of said outlet port includes a fitting for connecting said outlet to a hose for evacuation of said container.

5. The shipping container according to any one of the preceding claims, wherein air 25 mats are further provided on the inside surfaces of said panels comprising said rear end wall at about the level of said outlet port.

6. The shipping container according to any one of the preceding claims, comprising from 10 to 25 air mats.

7. The shipping container according to any one of the preceding claims, comprising 30 from 3 to 7 vibra pads.

8. The shipping container according to any one of the preceding claims, comprising two said vibrators lying on the centre-line of said floor with one at about the mid-point between said outlet port and said front wall and the other about half way between said outlet port and the first-mentioned vibrator. 11

9. The shipping container according to any one of the preceding claims, comprising two said air lances in said outlet port.

10. The shipping container according to any one of the preceding claims, wherein inlets to said high and low pressure systems are duplicated on each side of said container. 5

11. The shipping container according to any one of the preceding claims, wherein said container further includes a pressure relief value in the roof thereof.

12. The shipping container according to any one of the preceding claims, wherein said container further includes an access door in the front end wall thereof.

13. The shipping container according to any one of the preceding claims, wherein said 10 container has the overall dimensions of an ISO shipping container.

14. A method of transporting a powdered material, the method comprising the steps of: a) charging a shipping container according to any one of claims 1 to 13 with said powdered material; b) moving said container to said delivery site; 15 c) connecting said container outlet port via a hose to a pneumatic conveying vessel for transferring said powdered material to a holding silo; d) fluidising settled powdered material adjacent said outlet port by supplying air to said air mats, vibra pads and at least one air lance while elevating the front end of said container; 20 e) transferring fluidised powder from said container to said silo; and f) activating said at least one vibrator towards completion of discharge of said powdered material.

15. The method according to claim 14, wherein in step (b) said container is moved by air, road, rail or sea. 25

16. The method according to claim 14 or 15, wherein in step (d) connection of said outlet port to said hose is by way of male and female components that can be clipped or clamped together but can be disengaged on completion of evacuation of the container.

17. The method according to any one of claims 14 to 16, wherein in step (d) said elevation is at an angle between 40* and 600 to the horizontal. 30

18. The method according to anyone of claims 14 to 17, wherein a plurality of containers are transported.

19. A shipping container for powdered material, which container is substantially as hereinbefore described with reference to the accompanying drawings. 12

20. A method of transporting a powdered material, which method is substantially as hereinbefore described with reference to Detailed Description of the Invention. Date: 28 April 2009