Assembly for transporting and storing powder

Abstract

The present invention relates to an assembly comprising a container configured to contain a quantity of powder and a support structure arranged to support the container, wherein the support structure comprises an upright hollow section and at least a part of the container penetrates the upright hollow section.

Description

[0001] Assembly for Transporting and Storing Powder

[0002] Technical Field of the Invention

[0003] The present invention relates to an assembly for transporting and storing powder. In particular, the present invention relates to an assembly for transporting and storing metal powder for use in an additive manufacturing process.

[0004] Background to the Invention

[0005] Additive manufacturing (AM) generally relates to the process of manufacturing 3D objects by building up layers of a material or materials. The materials may be supplied to additive manufacturing machines in the form of powders (e.g. metal powders). Currently, AM powders (e.g. sub-micron metal powders) are alloyed and milled at a powder manufacturing facility before being packed, under controlled atmosphere conditions, into airtight plastic containers, e.g., CurTec (RTM) bottles made form high density polyethylene (HDPE). However, these containers are limited by their size, meaning numerous small containers are needed when transporting large quantities of powder which is undesirable from a logistics perspective. Moreover, filling AM machines with powder that is being stored in multiple containers is an inefficient process that increases the risk of operator exposure and the risk of the powder and the environment being contaminated during logistics, transport, and handling. There is also an environmental impact associated with using plastic containers to transport and store powder. For example, approximately 17 kg of plastic waste is generated when transporting 450 kg of powder for use in an AM build.

[0006] Hoppers for transporting and storing larger quantities of AM powder are known. Such hoppers typically comprise an upper cylindrical section and a lower conical section comprising a mouth through which AM powder is discharged in use. Three V- section support legs are fixed to and are spaced circumferentially around the hopper.

[0007] The support legs are mounted onto an industry standard pallet system having 2-way access so that the hopper can be transported using a fork-lift truck. While such hoppers are able to transport greater quantities of powder compared to CurTec bottles, there remains a need for a hopper that is capable of holding greater quantities of powder per flat metre of footprint in response to the substantial increase in AM machine throughput in recent years.

[0008] It is an object of embodiments of the invention to provide a container that is capable of transporting and storing large quantities of AM powder and which is better able to distribute the load.

[0009] It is an object of embodiments of the invention to provide a container for transporting and storing AM powder which has a reduced impact on the environment.

[0010] It is a further object of embodiments of the invention to provide a container that can be moved easily within a warehouse or AM manufacturing facility.

[0011] It’s another object of embodiments of the invention to provide a container that minimises the risk of operator exposure and powder contamination.

[0012] Summary of the Invention

[0013] According to a first aspect of the invention there is provided an assembly comprising a container configured to contain a quantity of powder and a support structure arranged to support the container, wherein the support structure comprises an upright hollow section and at least a part of the container penetrates the upright hollow section. Due to the container extending into the upright hollow section the assembly is able to carry a larger volume of powder per flat metre of footprint compared to the conventional cylindrical hoppers comprising V-section support legs.

[0014] The upright hollow section may comprise a cut-out and at least a part of the container, including part of its internal volume, may reside within the cut-out formed in the upright hollow section. The upright hollow section may have a square crosssection. In some embodiments the upright hollow section may be made from steel.

[0015] The container may comprise an inverted square pyramidal portion and a cuboidal body portion. In some embodiments a part of the body portion and / or a part of the square pyramidal portion reside within the cut-outs.

[0016] The assembly may comprise a plurality of upright hollow sections. In particular, the assembly may comprise at least four hollow upright sections. The upright hollow sections may be arranged in use to receive corners of the container. By providing four upright hollow sections the assembly is better able to distribute the load than prior assemblies with three legs, meaning the assembly is more stable in use.

[0017] The container may comprise a top plate. The top plate may cover an open end of the body portion. By covering the body portion with the top plate, powder in the container can be transported and stored under inert conditions, e.g. under an inert atmosphere, which helps to ensure that the powder is not exposed to gaseous contaminants such as oxygen and that it does not come into contact with other foreign bodies that could lead to failed builds or negatively affect the final mechanical properties of built parts. The container may comprise a removable lid arranged, in use, to sealingly close an opening formed in the top plate. The top plate may comprise a circular opening. The opening may comprise a coupling member such as a ferrule. In use, the removable lid may seal against a mating surface of the ferrule. The removable lid and ferrule may be clamped together using a clamp which extends circumferentially around the lid and ferrule.

[0018] The removable lid may comprise one or more fittings. The fittings allow valves, gauges, and other ancillaries to be connected to the lid and communicate with the internal volume of the container. For example, at least one fitting may serve as an inlet so that powder may be admitted into the container. This powder inlet may be connected to a first flow control device for controlling the flow of powder into the container. In some embodiments the powder inlet may be connected to a butterfly valve. At least one of the fittings may serve as a gas inlet. The gas inlet may be connected to a second flow control device for selectively controlling the flow of a gas into the container. The gas may comprise air or an inert gas such as argon for preserving the condition of the powder in the container. The second flow control device may comprise a ball valve. In particular, the gas inlet may comprise a push fit ball valve. A pressure gauge and a pressure release valve may be respectively coupled to fittings on the lid so that pressure in the container can be monitored and controlled.

[0019] In some embodiments powder may be conveyed into or out of the container under vacuum with powder entering or exiting the container via the first flow control device. The upright hollow sections may extend above the height of the fittings. In embodiments where ancillaries such as the first and second flow control devices, pressure gauge and pressure release valve are connected to the fittings, then the upright hollow sections may extend above the ancillaries. This serves to protect the fittings, ancillaries and the top of the container in use and during transport as well as removing the need for a removable transport frame. In this regard, if the container toppled over, the upright hollow sections would absorb the impact.

[0020] The container may comprise an outlet. In particular, the square pyramidal portion of the container may comprise the outlet. A coupling member may be mounted within the outlet for connecting the outlet to a third flow control device, e.g. a butterfly valve, for controlling the flow of powder out of the container. In this way, powder exiting the container via the outlet can be discharged into an additive manufacturing machine or into another component of an additive manufacturing process in a controlled manner. The coupling member may comprise a ferrule having a radially outwardly extending connection flange.

[0021] The assembly may comprise a plurality of gussets which, in use, extend between the upright hollow sections and an upper surface of the container. Each upright hollow section may be provided with two gussets. The gussets may be arranged at right angles to each other. The gussets serve to strengthen the connection between the upright hollow sections and the container.

[0022] The assembly may comprise a base. The base may be connected to and extend between the upright hollow sections. The base serves to strengthen and increase the overall rigidity of the assembly. The base may be configured to receive the forks of a forklift or pallet truck. In some embodiments, the base may comprise four sides and each side may comprise a pair of passages for receiving the forks of the forklift or pallet truck. Such an arrangement facilitates transport of the container within a warehouse or additive manufacturing facility since it can be accessed from the front, the rear and from both sides. This is particularly advantageous if the assembly is to be transported using a forklift truck and space to manoeuvre is limited.

[0023] The upright hollow sections may comprise a top cap. The top cap may be configured to receive a lifting bolt so that the assembly can be lifted by a crane. The 10 lifting bolt may comprise a threaded tail portion and a looped portion. The top cap may comprise a threaded aperture and a hex nut which are adapted to receive the threaded tail of the lifting bolt. The hex nut may be welded to the top cap and in use may be housed within the upright hollow section. The top cap may be welded to the upright hollow section. In some embodiments the assembly may be provided with the lifting bolts.

[0024] The assembly may comprise an earthing point. The earthing point safeguards against electrostatic discharge to protect users handling the assembly in use. At least one of the hollow upright sections may comprise the earthing point. The earthing point may comprise a metal or metal alloy stud, e.g. formed from stainless steel. The stud may be threaded and may be securable within a threaded hole formed in a wall of at least one upright hollow section. In other embodiments, the stud may be welded within the upright hollow section, to create a strong permanent bond. The hollow upright sections may comprise a bottom cap. In some embodiments the hollow upright sections may comprise a skid plate. The skid plate may be formed from a polymeric material. In particular, the polymeric material may comprise nylon.

[0025] A brace plate may extend between a pair of upright hollow sections. The brace plate serves to improve the strength and rigidity of the assembly in use. This is particularly advantageous for larger containers which are designed to hold heavier loads of powder. The assembly may comprise at least four brace plates, each extending between a different pair of upright hollow sections. In this way, each side of the assembly comprises a brace plate which ensures that the load is distributed evenly. In some embodiments two or more brace plates may extend between a pair of upright hollow sections.

[0026] The components of the container assembly may be formed from a metal or metal alloy such as stainless steel. The support structure may be welded to the container. In particular, the upright hollow sections may be welded to the container to secure parts of the container within the cut-outs. The base may be welded to the upright hollow sections. The gussets may be welded to the upper surface of the container and to the upright hollow sections. The brace plates may be welded to the upright hollow sections.

[0027] The interior of the container may be smooth to facilitate flow of powder out the container. The exterior of the container may be free from cracks and crevices to minimise the risk of powder contamination.

[0028] The assembly may comprise display information. For example, the container may comprise information relating to the type of the powder being stored in the container. The container may comprise a QR or other machine -readable code which links to software that stores and manages data relating to the condition of the powder in the container. This enables an operative to understand whether powder can be introduced into an AM process. The display information may comprise general or individual information about the hopper, such as build information, certificates, user guides, powder containment history and powder specifications for example.

[0029] According to a second aspect of the invention there is provided a hollow section for use in the assembly according to the first aspect of the invention, wherein the hollow section comprises a cut-out which is adapted to receive a part of the container.

[0030] The hollow section may have a generally square-cross section.

[0031] The cut-out may comprise a lower curved portion and a sloped upper portion.

[0032] Detailed Description of the Invention

[0033] In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0034] Figure 1 is a front perspective view of the assembly for transporting and storing AM powder comprising a base;

[0035] Figure 2 is a rear perspective view of the assembly shown in Figure 1 ;

[0036] Figure 3 is a front view of the assembly shown in Figure 1 ;

[0037] Figure 4 is a top view of the assembly shown in Figure 1;

[0038] Figure 5 is a bottom view of the assembly shown in Figure 1 ;

[0039] Figure 6 is a perspective view of a partially assembled base separate from the assembly shown in Figure 1 ; Figure 7 is a perspective view of a fully assembled base shown in Figure 1 ;

[0040] Figure 8 is an exploded perspective view of a hollow upright section comprising a top cap and a bottom cap;

[0041] Figure 9 is a cross-sectional view of the upright hollow section comprising a top cap and a bottom cap; and

[0042] Figure 10 is a front perspective view of a hollow upright section.

[0043] Referring to the drawings, Figures 1-3 show an assembly 100 which comprises a container 10. The container 10 may include powder, e.g. metal powder, for an additive manufacturing process.

[0044] The container 10 comprises an inverted square pyramidal portion 11 having tapering side walls 12 that lead to an outlet 13. The container also comprises a body portion 14. The body portion 14 is integral with the square pyramidal portion 11 and is cuboidal in shape. The body portion 14 comprises four side walls 15 that extend upwardly above the inverted square pyramidal portion 11. The side walls 15 are joined together at their edges to define four upwardly extending corners. The container 10 comprises a bevelled or chamfered edge 16 that extends between the sidewalls 15 and a top plate 17.

[0045] The top plate 17 comprises a circular opening which allows powder to be admitted into the container 10. A removable lid 18 is provided for closing the circular opening. The lid 18 comprises an annular groove on an underside thereof for receiving a seal. The seal may be made from food-grade silicone or a synthetic rubber such as ethylene propylene diene terpolymer (EPDM). In use, the lid 18 seals against a first coupling member (not shown) mounted within the circular opening. In this embodiment the first coupling member is a ferrule. The first coupling member comprises an annular collar portion with an annular connection flange at one end. The annular connection flange may comprise an annular indentation on an upper surface thereof for receiving a seal, e.g. an O-ring. The lid 18 is clamped to the first coupling member using a clamp 5 19. The clamp 19 comprises a pair of curved arms 20 which each define a recess for receiving respective flanges of the coupling member and the lid 18. In this embodiment, the arms 20 each have a first end 21 and a second end 22. The arms 20 are connected at their first ends 21 which allows the arms 20 to pivotally move relative to one another. The clamp 19 also comprises a catch 23 for releasably connecting the arms 20 at their second ends 22. The catch 23 may have a mechanism for adjustably drawing the second ends 22 of the clamp arms 20 towards each other.

[0046] The lid 18 is provided with a plurality of apertures with fittings that allow valves, gauges, and other ancillaries to be connected to the lid 18 as appropriate and communicate with the internal space within the container 10. In this embodiment the lid 18 is provided with a first valve arrangement 24 for controlling the flow of powder into the container 10 through an aperture in the lid 18. In particular, the first valve arrangement 24 is in the form of a butterfly valve. However, it will be appreciated that the first valve arrangement 24 can comprise any suitable valve type for controlling the flow of powder into the container 10. As best shown in Figure 4, the butterfly valve 24 comprises a first handle 25 which, in use, may be used to open and / or close the butterfly valve 24. The lid 18 also comprises a gas inlet 26a and a gas outlet 26b to which respective ball valves 27a, 27b are connected. The gas inlet 26a and gas outlet 26b allow the atmosphere inside the container 10 to be controlled. In this respect, the gas inlet 26a can be used to admit a gas into the container 10, whilst the outlet 26b can be used as a balancing line. Accordingly, the gas inlet 26a and gas outlet 26b may be used to control a pressure level inside the container 10. For example, it may be desirable to increase the pressure within the container 10 to aid flow of the powder from the outlet 13. The gas may in some instances comprise air or a specific type of gas that is capable of preserving the condition of the powder in the container 10. For example, the gas may comprise an inert gas (e.g. argon, nitrogen, etc.) which may suitably inhibit oxidation or other deterioration of the powder within the container. The lid 18 is additionally provided with a pressure gauge 28 and a pressure release valve 29 which allows the pressure within the container 10 to be monitored and controlled respectively.

[0047] 10 The outlet 13 of the container 10 is adapted for connection to a second valve arrangement 30 which is configured to control the flow of powder out of the container 10 into a component of an additive manufacturing process, e.g. into an additive manufacturing machine. The second valve arrangement 30 may comprise a butterfly valve. A second coupling member in the form of a ferrule is mounted within the outlet 13 so that the outlet can be coupled to the second valve arrangement 30. The second coupling member comprises an annular connection flange. This annular connection flange comprises an annular indentation on an outer surface thereof for receiving a seal.

[0048] The second coupling member is hollow and defines an outlet port through which flowable material can exit the container 10. The annular connection flange of the second coupling member is secured against a corresponding flange of the second valve arrangement 30 using a second clamp 31. The opposite end of the second valve arrangement 30 comprises a further flange so that it may be coupled to an additive manufacturing machine for example, or to another component of an additive manufacturing process. Clamps sold under the trade mark TRI-CLAMP are also suitable for securing the annular connection flange of the second coupling member to the corresponding flange of the second valve arrangement 30.

[0049] The assembly 100 comprises four elongate, upright hollow sections 32 or ‘legs’ which, in use, support the container 10. The legs 32 have a generally square cross- section with curved corners and house the upwardly extending corners of the body portion 14. As best shown in Figures 8 and 10, each leg 32 comprises a cut-out 33 for receiving the corners of the body portion 14. The cut-out 33 comprises a sloped upper portion 33a for receiving the bevelled or chamfered edge 16 and a curved lower portion 33b for receiving the container 10 at the junction between the body portion 14 and the inverted square pyramidal portion 11. The body portion 14, the inverted square pyramidal portion 11 and the bevelled or chamfered edge 16 are welded to the legs 32 to secure the container 10 therein. So, part of the internal volume of the container 10 extends into the interior of the legs 32.

[0050] The legs 32 are arranged to extend above the first valve arrangement 24, the gas inlet 26, the pressure gauge 28, and the pressure release valve 29 (hereafter collectively referred to as “ancillaries”). This helps protect the ancillaries in use. The assembly 100 also comprises a plurality of gussets 34 which extend between an upper surface of the container 10 and an exterior surface of the legs 32. Each leg 32 is connected to two gussets 34. The gussets 34 are arranged at right angles to each other, and the base of 20 each gusset 34 is tapered to accommodate the bevelled or chamfered edge 16. The gussets 34 serve to strengthen the connection between the legs 32 and the container 10.

[0051] Each leg 32 comprises a top cap 35. The top cap 35 is welded to the leg 32 and comprises an aperture 36 and a hex nut 37. The hex nut 31 is welded to the underside of the top cap 35 and, in use, is housed within the leg 32. The aperture 36 and hex nut 37 are dimensioned and arranged to receive a lifting bolt (not shown) so that the assembly 100 can be lifted by a crane or other lifting device. The lifting bolt comprises a threaded tail portion which threadably engages the hex nut 37 and a looped portion 5 for engaging a component of the crane or other lifting device. Each leg 32 also comprises a bottom cap 38 which in use serves as a skid plate to protect and reinforce the bottom of the leg 32. The bottom cap 38 is formed from nylon and comprises a central circular opening 39. Each comer of the bottom cap 38 also comprises a frustoconical opening 40 which enables the bottom cap 38 to be secured to the leg 32 using suitable fasteners (not shown).

[0052] The assembly 100 comprises a base 41 which serves to the strengthen and increase the overall rigidity of the assembly 100. The base 41 is formed from four substantially identical tubular members 42 having a rectangular cross-section which interlink and are connected together to form a hash-shaped frame. Each tubular member 42 comprises a first end 43 having a first rectangular opening 43 a and a second opposite end 44 having a second rectangular opening 44a. The first and second rectangular openings 43a, 44a serve as access points for the forks of a forklift or pallet truck which extend through the tubular members 42 in use. The first and second ends 43, 44 of each tubular member 42 comprise cut away parts that are located inward from the first and second openings 43a, 44a. The cut-away parts define respective channels 43b, 44b that extend in a direction perpendicular to the long axis of the tubular member 42. The first end 43 comprises a u-shaped channel 43b while the second end 44 comprises an n- shaped channel 44b. The u-shaped and n-shaped channels 43b, 44b are substantially the same size and shape and are positioned so that, in use, the n-shaped channel 43b of one tubular member 42 faces and engages the u-shaped channel 44b of another tubular member 42 arranged transversely thereto. The tubular members 42 are then welded together along the adjacent edges of the members forming the channels. The rigid hashshaped frame is then welded to the legs 32 as shown in Figure 1 to provide a rigid support structure for the container. As best shown in Figure 1 , the tubular members 42 are spaced at the same height from the bottom of the legs 32, meaning the first and second openings 43 a, 44a of each tubular member 42 are accessible in the same plane. This has the advantage of standardising fork entry from all sides. It also has the benefit of providing a substantial flat area beneath the base 41 so that the base 41 (and therefore the assembly 100) can be lifted and transported securely by a pallet truck. Due to the tubular members 42 being spaced at the same height from the bottom of the legs 32, the container 10 is also able to sit closer to the ground thereby lowering its centre of gravity.

[0053] It also creates strapping points low to the ground for transportation, where straps can loop between the first and second ends 43, 44 at each corner of the base 41.

[0054] 15 As best shown in Figure 7, the base 41 comprises four sides and each side comprises a first opening 43a and a second opening 44a which, in use, define a pair of access points for receiving the forks of a forklift or pedestrian truck. Since the base 41 of the assembly 100 has ‘four-way access’ and can receive the forks of a forklift or pedestrian truck from the front, rear and from both sides, this facilitates handling and movement of the assembly 100 within a warehouse or AM facility.

[0055] Depending on the size of the container 10 the assembly 100 may comprise a plurality of rectangular braces plates (not shown). For example, for larger containers 10 such as those shown in Figures 1-3 that are configured to hold heavier loads, e.g., 500 L of powder, each side of the assembly 100 may be provided with a brace plate which extends between and is substantially perpendicular to a pair of legs 32. For smaller assemblies which are configured to hold lighter loads, e.g., 250 L of powder, the brace plates can still be provided but are not strictly necessary.

[0056] To dissipate the build-up of electrostatic charge the assembly 10 is provided with an earthing point 45 in the form of a stainless-steel stud. The stud is welded within a hole formed in the wall of at least one leg 32. However, in other embodiments the stud may be threadedly connected to the leg 32.

[0057] As best shown in Figures 1-3, the container 10 comprises a holder 46 for storing documents which is fixed to an exterior surface of one of the side walls 15. Display information 47 may also be provided on an exterior surface of the base 41 as shown in Figure 3.

[0058] The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

CLAIMS1. An assembly comprising a container configured to contain a quantity of powder and a support structure arranged to support the container, wherein the support structure comprises an upright hollow section and at least a part of the container penetrates the upright hollow section.

2. An assembly as claimed in claim 1, wherein the upright hollow section comprises a cut-out and at least a part of the container resides within the cut-out formed in the upright hollow section.

3. An assembly as claimed in claim 2, wherein the container comprises an inverted square pyramidal portion and a body portion having a square cross-section.

4. An assembly as claimed in claim 3, wherein a part of the body portion and a part of the square pyramidal portion reside within the cut-out.

5. An assembly as claimed in claim 4, wherein the assembly comprises at least four hollow upright sections.

6. An assembly as claimed in any of claims 1 to 5, wherein the container comprises a top plate to provide a sealed interior volume.

7. An assembly as claimed in claim 6, wherein the container comprises a removable lid arranged, in use, to sealingly close an opening formed in the top plate.

8. An assembly as claimed in claim 7, wherein the removable lid comprises one or more fittings.

9. An assembly as claimed in claim 8, wherein at least one fitting is connected to first flow control device for controlling the flow of powder into the container.

10. An assembly according to claim 8 or 9, wherein at least one fitting is connected to a second flow control device for controlling the flow of a gas into the container.

11. An assembly as claimed in claims 8 to 10, wherein the upright hollow sections extend above the height of the fittings, the first flow control device and the second flow control device.

12. An assembly as claimed in any preceding claim, wherein the container comprises an outlet within which is mounted a coupling member for connecting the outlet to a third flow control device for controlling the flow of powder out of the container.

13. An assembly according to claim 12, wherein coupling member comprises a ferrule having a radially outwardly extending connection flange.

14. An assembly as claimed in any preceding claim, wherein the assembly comprises a plurality of gussets which in use extend between the upright hollow sections and an upper surface of the container.

15. An assembly as claimed in any preceding claim, wherein the assembly comprises a base which extends between and is connected to the upright hollow sections.

16. An assembly as claimed in claim 15, wherein the base is configured to receive the forks of a forklift or a pedestrian truck.

17. An assembly as claimed in 16, wherein the base comprises four sides and each side comprises a pair of passages for receiving the forks of the forklift or pedestrian truck.

18. An assembly as claimed in any preceding claim, wherein the upright hollow sections comprise a top cap configured to receive a lifting bolt so that the assembly can be lifted by a crane.

19. An assembly as claimed in any preceding claim, wherein the assembly comprises an earthing point.

20. An assembly as claimed in any preceding claim, wherein the hollow upright sections comprise a bottom cap.

21. An assembly as claimed in any preceding claim, wherein a brace plate extends between a pair of upright hollow sections.

22. An assembly as claimed in any preceding claim, wherein the upright hollow sections are welded to the container.

23. A hollow section for use in the assembly as claimed in any preceding claim, wherein the hollow section comprises a cut-out which is adapted to receive a part of the container.

24. A hollow section as claimed in claim 23, wherein the hollow section has a square-cross section.

25. A hollow section as claimed in claim 23 or claim 24, wherein the cut-out comprises a curved lower portion and a sloped upper portion.

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