GB2620611A

GB2620611A - A method and apparatus for forming a steady stream of plasticised solid feed material

Info

Publication number: GB2620611A
Application number: GB2210313.9A
Authority: GB
Inventors: Mistry Nimisha; Avis Jonathan; Hoppenbrouwers Marc; De Schipper Mathijs; Rijfers Andre
Original assignee: Kraft Foods Schweiz Holding GmbH
Current assignee: Kraft Foods Schweiz Holding GmbH
Priority date: 2022-07-13
Filing date: 2022-07-13
Publication date: 2024-01-17
Also published as: GB202210313D0; WO2024013191A1

Abstract

An apparatus 10 for forming a steady stream of plasticised solid feed material comprises: a piston-in-cylinder ram 11 to compact shredded solid feed material to form a solid billet 12 of plasticised solid feed material in the cylinder 13 which extrudes at least a portion of the solid billet from an exit end of the cylinder; a transfer path 14 in communication with the exit end of the cylinder 13; and a heater 15 associated with at least a portion of the transfer path 14 to plasticise the plasticised solid feed material and heat to temperature to form a plasticised solid feed material. The corresponding method is also disclosed.

Description

A METHOD AND APPARATUS FOR FORMING A STEADY STREAM OF PLASTICISED SOLID FEED MATERIAL

Technical Field of the Invention

The present invention relates generally to methods and apparatus for processing a particulate solid material to form a plasticised solid feed material. The invention further relates to methods and apparatus for forming a plasticised solid feed material from food products, in particular confectionery products, and products obtained therefrom.

Background to the Invention

It is also known to provide 3D printing of food such as confectionery. For example, US2012/0251688 provides a 3D printer for the 3D printing of chocolate in which the apparatus includes a reservoir configured to shear and heat a chocolate material to provide flowable chocolate, a pump configured to pump the flowable chocolate material from the reservoir and a print head configured to receive the pumped flowable chocolate material and extrude a portion thereof to form a 3 -dimensional solid object.

Likewise. US2017/0259482 describes an apparatus and process for the 3D printing of chocolate comprising a printer cartridge having a cartridge barrel for containing a chocolate print material, an extruder having a nozzle and a pneumatic system for enabling pressurised air to push the print material from the printer cartridge to the extruder.

Known 3D chocolate and confectionery extruders therefore generally utilise cartridges or containers of molten and/or tempered chocolate which are pushed, via pressure through an extrusion die head as the printer head. In such apparatus, it can be very difficult to control pressures within the system or apparatus, and the use of cartridges or reservoirs means that batch processing is generally undertaken, rather than continuous processing, Similarly. European patent No. EP3902405 discloses a 3D printing apparatus comprising at least one print head, a supply system for continuously supplying at least one print material to the or each print head in a flowable state, and at least one pressure regulation device for regulating the back pressure of the or each tlowable print material to the or each print head. The supply system may comprise at least one supply path and, in this application, includes at least one screw-containing pump (or rotor-containing pump).

Current 3D processes use liquid tempered chocolate to be filled into cartridges, which are then cooled and stored for crystallization before use in the 3D printer. This invention eliminates this process step by using a steady stream of ambient solid (crystalized) chocolate as a direct feed to the 3D printer or to fill the 3D printing cartridges It would therefore be advantageous to provide a 3D printing apparatus and method, suitable for the 3D printing of chocolate and other confectionery, in which a continuous process is possible, which continuous process may be modified in situ, and in which changes in material flow, volume and consistency can be accommodated without stopping or negatively affecting the 3D printing process.

It would also be advantageous to provide a 3D printing apparatus, particularly for confectionary and chocolate, in which extrusion of the chocolate may be performed with a solid start material (such as chocolate flakes or powder), and which can be performed continuously, irrespective of changes to the volume, flow rate or consistency of the chocolate material.

It is therefore an aim of embodiments of the present invention to overcome or

mitigate at least one problem of the prior art.

Summary of the Invention

According to a first aspect of the invention, there is provided an apparatus for forming a steady stream of plasticised solid feed material, the apparatus comprising: a. a piston-in-cylinder ram to compact shredded, solid feed material to form a solid billet of feed material in the cylinder and to extrude at least a portion of the solid billet from an exit end of the cylinder; b. A transfer path in communication with the exit end of the cylinder; c. A heater associated with a portion of the at least a portion of the transfer path to plasticise the feed material and heat to temperature to form a feed of plasticised, solid feed material.

According to a second aspect of the invention, there is provided a method for forming a steady stream of plasticised solid feed material, the method including the steps of: a. Introducing shredded, solid feed material to a piston-in-cylinder ram; b. Compacting the shredded feed material to form a solid billet of feed material in the cylinder; c. extruding at least a portion of the solid billet from an exit end of the cylinder into a transfer path in communication with the exit end of the cylinder; d. heating the feed material in at least a portion of the transfer path to plasticise the feed material and heat the feed material to temperature to form a feed of plasticised, solid feed material.

Providing an apparatus and method to process a particulate solid material to form a plasticised solid feed material as described forms a solid billet in the cylinder and then extrudes the solid billet material into a conduit which is heated to temperature, to form a direct feed of plasticised solid feed (crystallised) chocolate for use by a 3D printer or to be loaded into a cartridge use by a 3D printer. Crystallised chocolate is formed by tempering so that the cocoa butter in the chocolate takes on a stable crystalline form. Properly crystallised chocolate has desirable texture characteristics, such as good 'snap' and mouth feel, a glossy appearance and resists melting. Products formed using under crystallised chocolate have a chocolate shell with a grey colour, dull spots, and would melt at the touch. Moreover, moulded chocolates and hollow figures formed using under crystallised chocolate would harden very slowly and be very difficult to un mould and have a less than optimum appearance.

Whilst the present invention may be described with more particular reference to formation of a plasticised solid feed material, particularly a food material such as chocolate, in a 3D printing or forming process, the plasticised solid feed material, 30 depending upon the type of material used, can be used for a broader range of forming processes, such as in extrusion, to deposit 'reformed' chocolate or other feed material onto a shaped belt or into a mould, or to co-extrude it with a filling for example.

The or each feed material may comprise any material which is in a solid state, preferably a particulate solid state at ambient temperature (e.g room temperature), which can be heated into a plasticised but still solid state.

The or each feed material may comprise a polymeric material, an elastomeric material, a plastic material, a plastics material or a food material. In preferred embodiments the feed material is a food material, more preferably a confectionery material. In especially preferred embodiments, the confectionery material is chocolate, such as milk chocolate, dark chocolate, white chocolate or compound chocolate.

The apparatus preferably forms a steady stream of plasticised solid feed material exiting the transfer path. The piston-in-cylinder ram firstly forms a solid compressed billet in the cylinder and then the material is plasticised whilst conveyed through the transfer path.

The definition of plasticised, solid feed material is important. It is plasticised, solid feed material form use in another, downstream process (to be contrasted with 'feed material' which is fed into the process to form the plasticised, solid feed material). The feed material entering the process/apparatus will preferably be solid, and may be particulate solid. It is important that the feed material exiting the process/apparatus is solid but softened or plasticised to allow forced flow through the transfer path.

Preferably, the plasticised, solid feed material will not flow once the driving force applied by the piston-in-cylinder ram is removed. The plasticised solid material inside the piston-in-cylinder ram is not a liquid and preferably will not flow under the influence of gravity. To achieve this state of plasticised solid feed material, the temperature of the plasticised solid feed material should remain below the melting temperature of the feed material. As an example, for a chocolate feed material (although dependent on the makeup of the chocolate), this temperature is generally between 23°C and 35°C, preferably approximately 29°C. It is preferred that the temperature of the feed material at the exit from the transfer path is approximately 29°C as this will preferably be plasticised solid feed material. It is preferred that the temperature of the plasticised solid feed material is below 30°C at all times during the process. The chocolate is preferably not melted at any stage, but rather it is plasticized or softened or otherwise warmed, to be transportable through the process and for use in a subsequent process.

The apparatus includes a piston-in-cylinder ram to compact shredded feed material to form a solid billet of feed material in the cylinder and to extrude at least a portion of the solid billet from an exit end of the cylinder.

Shredded feed material may be fed to the piston-in-cylinder ram. The shredded feed material may have a size of between lmm to 5mm There will normally be a distribution of sizes of shredded feed material in the feed to the piston-in-cylinder ram.

The feed material may be pieces, lumps, 'buttons', granules, or the like. The feed material may be provided in a larger size and broken up or otherwise reduced in size to feed the piston-in-cylinder ram.

A cylinder filling hopper or similar may be provided to collect and direct the shredded feed material into an upper end of the piston-in-cylinder ram. In one form, the shredded feed material may be gravity fed into an upper end of the piston-in-cylinder ram. Agitation may be provided to assist with the filling of the piston-in-cylinder ram. The hopper and/or the piston-in-cylinder ram may be agitated to assist with filling.

The piston of the piston-in-cylinder ram will preferably reciprocate. The piston will preferably move in a substantially vertical direction.

The piston-in-cylinder ram may be located at a lower end of the cylinder filling hopper. The piston of the piston-in-cylinder ram may extend through the exit opening of the cylinder filling hopper. This may assist with pressing shredded feed material into an upper end of the piston-in-cylinder ram.

A lower end of the piston will preferably clear the upper end of the exit opening of the cylinder filling hopper at the top of the up stroke of the piston. This may allow more shredded feed material to enter the upper part of the cylinder, preferably assisted by gravity and/or agitation.

On the downward stroke of the piston, the shredded feed material is initially compacted at an upper part of the cylinder. This initial compaction will preferably allow much of the air to escape the cylinder about the piston. Further downward movement of the piston in the cylinder will then preferably act to compress the compacted shredded feed material to form a solid billet of feed material at a lower part of the cylinder. A lower end of the cylinder is preferably convergent leading to the exit from the cylinder in order to assist the formation of the billet in the lower part of the cylinder. The billet is preferably a solid mass of compressed material.

The billet may be always present within a lower part of the cylinder, that is the piston never makes it to the exit end of the cylinder such that a 'billet' of material remains in the cylinder. Alternatively, the piston may extrude all of the billet before returning on an upstroke to refill. This alternative is less preferred as it may allow air to become trapped in the cylinder and/or within the billet itself.

The cylinder is preferably relatively small in diameter in order to minimise the force required to compress the material into a billet. A preferred internal diameter of the cylinder is between 15mm and 500mm. For relatively small-scale embodiments, an IS internal diameter of approximately 20 mm is preferred.

An air gap clearance may be provided between an outer cylindrical surface of the piston and the inner cylindrical surface of the cylinder. This air gap clearance may allow air from within the shredded feed material to escape during compaction and/or compression. The air gap may be approximately 0.1mm. For example, the internal diameter of the cylinder may be 22.5mm and an outer diameter of the piston may be 22.3mm The piston speed is preferably relatively slow on the downstroke. The speed of the downstroke may be lower than the speed of the upstroke. A downstroke speed of between lmm/s and 5mails is preferred with approximately 1 5mm/s being particularly 25 preferred.

The piston may have a flattened or a shaped tip end. A convex shaped tip end may be preferred.

Compaction and/or compression of the shredded feed material in the cylinder may increase the temperature of the material in the cylinder. As mentioned above, it is important that the temperature of the material remain relatively low. The temperature of the cylinder may be controlled to control the temperature of the material in the cylinder. Cooling may be provided. A cooling mechanism may be provided about the cylinder, or a part thereof, particularly a lower part where the compression of the shredded feed material preferably occurs. The compression in the lower part of the cylinder may at least to begin to plasticise the feed material in the billet within the lower part of the cylinder.

Cooling may be provided immediately after the exit from the cylinder. Cooling may be provided relative to a part of the transfer path immediately after the exit from the cylinder. Preferably, cooling may be provided between the exit from the cylinder and the heater. Any method of cooling may be used for example, a fan or cooling jacket. Any cooling may preferably act circumferentially about the part of die transfer path. A material temperature of approximately 15°Cand 20°C may he preferred at this point.

The cylinder may he between 100mm and 500mm in length. For benchtop examples, the cylinder may he between 100mm and 150mm and most preferably approximately 125mm in length. The length should be sufficiently long to allow initial compaction of the shredded feed material at an upper portion of the cylinder and then compression into a billet at a lower part of the cylinder. If the billet is too large in the cylinder, then the force required to move it will increase but it is also important that the billet is formed in the cylinder and that a portion of billet remain at a lower part of the cylinder to minimise air in the transfer path which is undesirable for consistent product.

A cylinder of approximately 125mm in height allows a compaction height of approximately 60num to 65mm and a compression height (billet height) of approximately 60mm to 65mm. Where the size of die cylinder changes, the proportion /5 of compaction height to compression height may remain similar or the same at approximately 1:1.

The apparatus also includes a transfer path in communication with the exit end of the cylinder. The transfer path may be an elongate conduit. The length of the transfer path is important as it should be sufficiently long to allow heating of the billet (for example, to allow a chocolate feed material to reach a plasticised state) hut not too long as the length of the transfer path will increase friction forces in the transfer path which in turn will require more force from the piston-in-cylinder ram to drive the billet through the transfer path.

The piston-in-cylinder ram will also preferably act to drive at least a portion of the billet through the transfer path.

A slower temperature rise in the billet is preferred to a quicker temperature rise.

A slower temperature rise in the billet is preferably more controllable. The length of the transfer path is therefore preferably optimised to heat the billet to a preferred temperature and then to maintain the temperature for the billet at that temperature for the remainder of the length of the transfer path.

The transfer path may be a substantially circular cross-section conduit. The conduit will preferably have a suitably small internal diameter to minimise any boundary layer effects. This may allow the billet to be heated and plasticise entirely through the thickness of the billet while travelling through the conduit.

The length of the conduit and the internal diameter of the conduit will be related parameters. For example. a conduit of between 2mm and 10mm in internal diameter is preferred and more preferably approximately 4-5mm in internal diameter. At approximately 4-5mm in internal diameter, the conduit will preferably be between 500-1000m m in length, more preferably between 700-900mm in length and most preferably, between 800-830mm in length. This may provide sufficient length to heat the billet in the conduit to plasticise the billet whilst allowing the use a heater which maintains the material at a sufficiently low temperature so as not to melt the billet. Where the conduit is larger, similar proportions may be used.

The transfer path conduit may be rigid rather than flexible given that the billet will be movable through the conduit under force, but not be liquid.

The conduit may be shaped. A sinuous or winding configuration is preferred.

This configuration may also create axial and/or circumferential mixing of the billet in the conduit as it traverses through the conduit rather than plug flow. This may act to mix the billet as it traverses through the conduit, exposing all parts of the billet to the heat and facilitating flow under force without melting.

The apparatus also includes a heater associated with a portion of the transfer path to plasticise the feed material and heat to temperature to form a feed of plasticised solid feed material.

The heater may be provided relative to a substantial part of the length of the transfer path. Preferably, a heater is provided relative to at least half and preferably at least three quarters of the length of the transfer path.

Any type of heater may be used. One or more heaters may be provided. Different heaters may be provided in different parts of the length of the transfer path. Preferably, all sides of the transfer path conduit are heated equally.

The heater may be or comprise a jacket heater and/or a bath heater. In one embodiment, a bath heater may be provided over a part of the length of the transfer path conduit and a jacket heater over another part of the length of the transfer path conduit. The bath heater may be provided closer to the exit end of the piston-in-cylinder ram and the jacket heater is provided after the bath heater.

The temperature of the billet in the transfer path is important as an elevated temperature is preferably required to plasticise the billet to allow flow under force, but the temperature is preferably sufficiently low to prevent melting. The temperature of the billet in the conduit will generally depend on a number of parameters but will preferably he between 23°C and 35°C, more preferably approximately 30°C and most preferably between 28°C and 32°C. Processing the billet at this temperature will preferably plasticise but not melt a billet of chocolate for example.

The apparatus may be used in connection with a 3D printing apparatus comprising at least one print head.

The transfer path may provide the plasticised solid feed material to at least one supply path for a 3D printing apparatus. In some embodiments, at least 2, 3, 4, 5, 6, 7, 8, 9 or at least 10 supply paths may be present. In preferred embodiments a single supply path may be provided.

The or each print head may comprise an additional piston-in-cylinder ram. The provision of an additional piston-in-cylinder ram in association with the or each print head may assist with the consistent expulsion of the plasticised solid print material. The or each print head may comprise a nozzle at its distal end. The presence of the nozzle helps to control the thickness of the printed material and/or to direct the flow of print material as it exits the print head.

In embodiments plasticised solid feed material is continuously supplied to the or each piint head and can be extruded out of the or each printed head at any desired rate, by adjusting feed at the feed end of the apparatus. Therefore, the rate of extrusion out of each print head may be individually controlled by if an individual feed apparatus is provided.

The or each supply path may comprise a single print head, or may comprise at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45 or at least 50 print heads and/or no more than 2, 3,4, 5, 6,7. 8, 9, 10, 15, 20,25, 30, 35, 40, 45 or no more than 50 print heads.

The at least one print head of a supply path may be arranged into at least one print module. In some embodiments, the or each supply path comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9 or at least 10 print modules. The or each print module may comprise at least 1, 2, 3, 4.5, 6,7, 8, 9 or at least 10 print heads. In some embodiments, the or each print module comprises between 3 to 7 print heads, such as 5 print heads.

The apparatus may be used to fill a tillable or refillable cartridge. The finable or refillable cartridge may function in a manner similar to a syringe. The fillable or refillable cartridge may include an elongate hollow barrel, an outlet at one end of the barrel and a movable plunger located within the barrel for movement toward the outlet for expulsion of material from the barrel and away from the outlet to allow filling of the bard.

The barrel may be made of any material but for a barrel handling food material, will preferably be metal and food grade stainless steel or similar is preferred. The barrel may have any suitable volume, preferably at least 50m1.

The outlet of the cartridge may have an attachment structure provided to allow the cartridge to be attached (releasably) to a 3D printer. A thread may be preferred. One or more structures such as a land or similar may be provided to allow a tool to be used to engage the outlet.

The plunger may be made of any material but for a food material, could be metal and food grade stainless steel or similar is preferred or a food grade plastic. One or more wiper seals may be provided between the plunger and the barrel. An outer side or portion of the plunger may include one or more abutment portions such as lands, to allow a printer to apply force to the plunger to force movement of the plunger, usually toward the outlet to expel material.

The cartridge may be oriented vertically or horizontally when it is to be filled. The tip of the cartridge may be uppermost or lowermost during filling. The cartridge may be mounted from the tip during filling. The cartridge may be attached relative to an indexing mechanism during filling to allow loading of multiple cartridges to be filled. A carousel or linear indexing mechanism may be used.

One method of filling a cartridge is to fill from the tip, forcing the plunger in the opposite direction, as the cartridge is filled.

An additional piston-in-cylinder ram may be used to inject material exiting the transfer path conduit into a cartridge.

A cartridge may be heated during the filling process to maintain the material in a plasticised form during filling. Although any type of heater could be used, a jacket heater may be preferred. The jacket heater may, in use, extend about the barrel of the cartridge during filling. The jacket heater may be split or provided in more than one part to allow the parts to be separated to load and remove the cartridges. The parts may be hinged relative to one another.

A coupling will preferably be provided between the exit from the transfer path and the tip of the cartridge. A mating dry break coupling is preferred as this may minimise or prevent leakage or loss of material when the cartridge is disconnected.

Back pressure or counter pressure may be applied to plunger of the cartridge during filling to prevent air building up in the cartridge. A back pressure of between I bar and 5bar is preferred with a back pressure of approximately 2bar being particularly preferred.

In one aspect of the present invention, there is provided a method for filling a cartridge with a plasticised solid feed material, the cartridge including an elongate hollow barrel, an outlet at one end of the hard and a hollow movable plunger located within the barrel for movement toward the outlet for expulsion of material from the barrel and away from the outlet to allow filling of the ban-el, the method comprising the steps of: Coupling the plunger of a cartridge relative to a piston-in-cylinder ram; Forcing the plasticised solid feed material through the tip to at least partially fill the barrel; and Applying a counter pressure to the plunger of the cartridge during filling to prevent air building up in the cartridge.

Detailed Description of the Invention

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: Figure 1 is a schematic view of an apparatus of an embodiment feeding a 3D printer including cartridges of plasticised solid feed material.

Figure 2 is a schematic view of an apparatus of an embodiment.

Figure 3 is an axonometric view of an apparatus of an embodiment used to form and fill cartridges with plasticised solid feed material.

Figure 4 is a sectional side view of a cartridge of an embodiment.

Figure 5 is a schematic sectional view of a plurality of cartridges in a partially filled configuration.

In the embodiments illustrated in Figures 1 to 3, an apparatus 10 for forming a steady stream of plasticised solid feed material is shown. The illustrated apparatus 10 comprises a piston-in-cylinder ram 11 to compact shredded feed material to form a solid billet 12 of feed material in the cylinder 13 and to extrude at least a portion of the solid billet 12 from an exit end of the cylinder 13. An elongate transfer path conduit 14 is provide in communication with the exit end of the cylinder 13. A heat bath 15 is associated with at least a portion of the transfer path conduit 14 to plasticise the feed material and heat to temperature to form a feed of plasticised solid feed material.

The apparatus illustrated in Figures 1 to 3 forms a steady stream of plasticised solid confectionery material (chocolate, such as milk chocolate, dark chocolate, white chocolate or compound chocolate) as a feed material, exiting the transfer path conduit 14. The piston-in-cylinder ram 11 firstly forms a solid compressed billet 12 in the cylinder 13 and then the material is plasticised whilst conveyed through the transfer path conduit 14.

For a chocolate feed material (although dependent on the makeup of the chocolate), the processing temperature of the billet in the transfer path conduit 14 is preferably approximately 29°C. It is preferred that the temperature of the feed material at the exit from the transfer path conduit 14 is approximately 29°C as this will preferably be plasticised solid feed material. It is preferred that the temperature of the plasticised solid feed material is below 30°C at all times during the process. The IS chocolate is then not melted at any stage, but rather it is plasticized or softened or otherwise warmed, to be plasticised.

Shredded, solid feed material is fed to the piston-in-cylinder ram 11. The shredded feed material may have a size of between lmm to 4mm. There will normally be a distribution of sizes of shredded feed material in the feed to the piston-in-cylinder ram 11.

As illustrated in Figure 1, a shredder 18 driven by a motor 21 is provided above a collection hopper 19 which shreds feed material and provides the shredded feed material to a laterally extending guide tray 20 which extends over a cylinder filling hopper 17. The guide tray is associated with a mechanical agitator 22 to agitate the shredded feed material to move it along the guide tray and over the cylinder filling hopper 17 In the embodiment illustrated in Figures 1 and 3, the cylinder filling hopper 17 collects and direct the shredded feed material into an upper end of the piston-in-cylinder ram 11. In the illustrated embodiment, the shredded feed material is gravity fed into an upper end of the piston-in-cylinder ram 11. An agitator 23 is associated with the cylinder filling hopper 17 to assist with the filling of the piston-in-cylinder ram II. In Figure 3, the shredder 18 is fed from a feed hopper 50.

The piston 16 of the piston-in-cylinder ram 11 will reciprocate in use. The piston 16 of the illustrated embodiment reciprocates in a substantially vertical direction.

The cylinder 13 is located at a lower end of the cylinder filling hopper 17, as shown in Figure 1. The piston 16 of the piston-in-cylinder ram 11 extends through the lower exit opening of the cylinder filling hopper 17.

As shown in Figure 1. a lower end of the piston 16 clears the upper end of the exit opening of the cylinder filling hopper 17 at the top of the upstroke of the piston 16. This may allow shredded feed material to enter the upper part of the cylinder 13, preferably assisted by gravity and/or agitation.

On the downward stroke of the piston 16, the shredded feed material is initially compacted at an upper part 23 of the cylinder 13 as shown in Figure 2. This initial compaction may allow much of the air to escape the cylinder 13 about the piston 16. Further downward movement of the piston 16 in the cylinder 13 will then preferably act to compress the compacted shredded feed material to form a solid billet 12 of feed material at a lower part 24 of the cylinder 13. A lower end of the cylinder 13 is preferably convergent leading to the exit from the cylinder 13 in order to assist the formation of the billet 12 in the lower part of the cylinder 13. At this stage, the billet 12 is preferably a solid mass of compressed feed material.

A billet 12 may be always present within a lower part 24 of the cylinder 13, that is, the piston 16 is never inserted into the cylinder 13 far enough to reach the exit end of the cylinder 13 such that a 'billet' of material remains in the cylinder 13.

The cylinder 13 is preferably relatively small in diameter in order to minimise the force required to compress the material into a billet 12. As illustrated, the internal diameter of the cylinder is approximately 20 mm.

An air gap clearance is provided between an outer cylindrical surface of the piston 16 and the inner cylindrical surface of the cylinder 13. This air gap clearance may allow air from within the shredded feed material to escape during compaction and/or compression. The air gap may be approximately 0.1mm. In the illustrated embodiment, the internal diameter of the cylinder is 22.5mm and an outer diameter of the piston is 22.3mm The piston speed is preferably relatively slow on the downstroke. The speed of the downstroke may be lower than the speed of the upstroke. A downstroke speed of approximately 1.5mm/s is particularly preferred.

Compaction and/or compression of the shredded feed material in the cylinder may increase the temperature of the material in the cylinder 13. As mentioned above, it is important that the temperature of the material remain relatively low.

In the illustrated embodiment, cooling 25 is provided immediately after the exit from the cylinder 13. Any method of cooling may be used for example, a fan to blow air 25 as shown in Figure 1 could be used or a cooling jacket 26 as shown in Figure 3.

Any cooling may preferably act circumferentially about the part of the transfer path. A material temperature of approximately 15°C to 20°C may be preferred at this point.

The cylinder 13 of the illustrated embodiment is approximately 125mm in length. The length is sufficiently long to allow initial compaction of the shredded feed material at an upper portion 23 of the cylinder 13 and then compression into a billet 12 at a lower part 24 of the cylinder 13. If the billet 12 is too large in the cylinder 13, then the force required to move it will increase but it is also important that the billet 12 is formed in the cylinder 13 and that a portion of billet 12 remain at a lovver part 24 of the cylinder 13 to minimise air in the transfer path conduit 14 which is undesirable for a consistent product.

The cylinder 13 shown in Figure 2 is approximately 125mm in height, allowing a compaction height of approximately 60mm to 65mm and a compression height (billet height) of approximately 60mm to 65mm.

As shown, the transfer path is an elongate conduit 14. The length of the transfer path conduit 14 is important as it should be sufficiently long to allow heating of the billet 12 (for example, to allow the chocolate feed material chocolate to plasticise without de-tempering/de-crystallising the material) but not too long as the length of the transfer path conduit 14 will increase friction forces in the transfer path conduit 14 which in turn will require more force from the piston-in-cylinder ram 11 to drive at least a portion of the billet 12 through the transfer path conduit 14.

The piston-in-cylinder ram 11 will act to compress the feed material and also to drive the billet 12 through the transfer path conduit 14.

The billet 12 is heated in the transfer path conduit 14. A slower temperature rise in the billet 12 is preferred to a quicker temperature rise. A slower temperature rise in the billet 12 is preferably more controllable. The length of the transfer path conduit 14 is therefore preferably optimised to heat the billet 12 to a preferred temperature and then to maintain the temperature for the billet 12 at that temperature for the remainder of the length of the transfer path conduit 14.

The transfer path conduit 14 of the embodiments shown is substantially circular in cross-section. The conduit 14 will preferably have a suitably small internal diameter to minimise any boundary layer effects. This may allow the billet 12 to be heated and plasticised entirely through the thickness of the billet 12 while travelling through the conduit.

The length of the conduit 14 and the internal diameter of the conduit 14 will be related parameters. The illustrated conduit 14 is approximately 4-5mm in internal diameter. At approximately 4-5mm in internal diameter, the conduit 14 is preferably between 800-830mm in length. This may provide sufficient length to heat the billet 12 in the conduit to plasticise the billet 12 whilst allowing the use of a heater which maintains the material at a sufficiently low temperature so as not to melt the billet 12.

The transfer path conduit 14 illustrated is rigid.

The conduit 14 has a sinuous or winding configuration as shown in Figure 2. This may act to mix the billet 12 as it traverses through the conduit 14, exposing all parts of the billet 12 to the heat and facilitating flow under force without melting.

As shown in the embodiments in each of Figures 1 to 3, a heater is provided relative to at least half and preferably at least three quarters of the length of the transfer path. Preferably, all sides of the transfer path conduit 14 are heated equally.

The heater in Figure 1 is a jacket heater 25. A bath heater 15 is provided over a part of the length of the transfer path conduit 14 in Figures 2 and 3. In Figure 3, a jacket heater 28 is provided over another part of the length of the transfer path conduit 14 after the bath heater 15.

The temperature of the billet 12 in the transfer path conduit 14 is important as an elevated temperature is required to plasticise the billet 12 to allow flow under force, but the temperature should remain preferably sufficiently low to prevent melting, de-tempering or over-softening. The temperature of the billet 12 in the conduit will generally depend on a number of parameters but will preferably be between 29°C and 30°C. Processing the billet 12 at this temperature will preferably plasticise but not melt a billet 12 of chocolate for example.

As shown in Figure 1, the apparatus 10 may be used in connection with a 3D printing apparatus comprising at least one print head.

As illustrated in Figure 1, a pair of cartridges 29 are provided each relative to a print platform. Each cartridge is associated with a supply path at a lower end in connection with the cartridge outlet which leads to two print nozzles 30. Each print nozzle 30 has a print cylinder 31 associated therewith to help with ensuring a consistent feed of print material from the cartridge to the print nozzle 30.

A single motor 32 is shown to move the plungers of both cartridges 29. A motor 33 is also provided to drive the two piint cylinders of each platform.

Actuated valves 34 are provided for filling and priming the supply path between cartridge outlet and the print nozzles 30. Actuated valves 35 are also provided at the print nozzles 30.

In Figure 1, there is an X-Y stage adjustor 36 for the print platform of each nozzle group and a Z stage adjustor 37 for the print platform of each nozzle group.

The apparatus may also be used to fill a finable or refillable cartridge 29 an example of which is shown in Figure 4. The fillable or refillable cartridge 29 may function in a manner similar to a syiinge. The fillable or refillable cartridge illustrated in Figure 4 includes an elongate hollow barrel 38, an outlet 39 at one end of the barrel 38 and a movable plunger 40 located within the bard 38 for movement toward the outlet 39 for expulsion of material from the barrel 38, and for movement away from the outlet 39 to allow filling of the barrel 38.

The barrel 38 may be made of any material but for a food material, a food grade stainless steel or similar is preferred. The barrel has a material volume 41 of approximately 300m1.

The outlet 39 of the cartridge may have an attachment structure such as a threaded portion (not shown) provided to allow the cartridge 29 to be attached (releasably) to a 3D printer (an example of which is illustrated in Figure 1).

One or more configurations such as a land 42 shown in Figure 4, may be provided to allow a tool (not shown) to be used to engage the outlet 39 to attach and detach from the loading system and the 3D printer.

The plunger 40 may be made of any material but for a food material, a food grade stainless steel or similar is preferred. One or more wiper seals 43 may be provided between the plunger 40 and the barrel 38. The plunger 40 may also include one or more abutment lands 44, to allow a printer, such as that shown in Figure 1, to apply force to the plunger 40 to force movement of the plunger 40 toward the outlet 39 to expel material from the cartridge 29.

As shown in Figures 4 and 5, the plunger 40 may be hollow with an opening at a forward end thereof. The cartridge 29 may be filled with material through the hollow plunger 40.

The cartridge 26 may be oriented vertically when it is to be filled as shown in Figures 3 or 5. The tip of the cartridge 26 may be uppermost during filling.

As shown in Figure 3, the cartridge 26 may be suspended from the tip during filling. The cartridge 26 may be attached relative to an indexing mechanism during filling to allow loading of multiple cartridges to be filled. A rotating indexing carousel, as shown in Figure 3 or linear indexing mechanism as shown in Figure 5 may be used. A servo motor 47 is used to drive the carousel through indexed rotation.

As shown in Figure 3, an additional piston-in-cylinder ram may be used to inject. material exiting the transfer path conduit into a cartridge 26. In Figure 3, the additional piston-in-cylinder ram is located inside jacket heater 28 and reciprocates as indicated by the large arrow.

As shown in Figure 3, a cartridge 26 may be heated during the filling process to maintain the material in a plasticised foun during filling. Although any type of heater could be used, a jacket heater 45 may be preferred. As shown in Figure 3, the jacket heater 45 may, in use, extend about the barrel 38 of the cartridge 26 during filling. The illustrated jacket heater 45 is split or provided in more than one part to allow the parts to be separated to load and remove the cartridges 26. The parts may be hinged relative to one another.

A mating dry break coupling 48 will preferably be provided between the exit from the transfer path conduit 14 and the (plunger 40 of the) cartridge 26 as this will minimise or prevent leakage or loss of material when the cartridge 26 is disconnected.

Back pressure or counter pressure 46 may be applied to plunger 40 of the cartridge 26 during filling to prevent air building up in the cartridge 26 as shown in Figure 2. A back pressure of approximately 2bar is particularly preferred in the illustrated embodiments.

As shown in Figure 3, a plunger drive 49 with a loadcell is used to apply the back pressure to the plunger during filling.

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 apparatus for forming a steady stream of plasticised solid feed material, the apparatus comprising: a. a piston-in-cylinder ram to compact shredded, solid feed material to Form a solid billet of feed material in the cylinder and to extrude at least a portion of the solid billet from an exit end of the cylinder; b. A transfer path in communication with the exit end of the cylinder; c. A heater associated with at least a portion of the transfer path to plasticise the solid feed material and heat to temperature to form a feed of plasticised solid feed material. 2. 3. 4. 5. 6. 7. 8.An apparatus as claimed in claim 1 wherein the feed material is a food material, optionally a confectionery material chosen from the group including chocolate, milk chocolate, dark chocolate, white chocolate or compound chocolate.An apparatus as claimed in claim 1 or claim 2 further including a cylinder filling hopper provided to collect and direct shredded, solid feed material into an upper end of the piston-in-cylinder ram.An apparatus as claimed in any one of the preceding claims wherein the piston of the piston-in-cylinder ram reciprocates and a lower end of the piston clears an upper end of the exit opening of the cylinder at the top of an up stroke of the piston.An apparatus as claimed in any one of the preceding claims wherein an air gap clearance is provided between an outer cylindrical surface of the piston and an inner cylindrical surface of the cylinder.An apparatus as claimed in any one of the preceding claims further comprising a cooling mechanism is provided immediately after an exit from the cylinder relative to a part of the transfer path immediately after the exit from the cylinder. An apparatus as claimed in any one of the preceding claims wherein the transfer path conduit is flexible.An apparatus as claimed in any one of the preceding claims wherein the transfer path conduit has a sinuous or winding configuration.9. An apparatus as claimed in any one of the preceding claims wherein the heater is provided relative to at least half and preferably at least three quarters of a length of the transfer path.10. An apparatus as claimed in any one of the preceding claims wherein a first heater is provided over a part of the length of the transfer path conduit.11. An apparatus as claimed in any claim 10 wherein a second heater is provided over another part of the length of the transfer path conduit after the first heater.12. An apparatus as claimed in any one of the preceding claims further comprising a fill station with at least one fillable or refillable cartridge relative to an exit end of the transfer path conduit.13. An apparatus as claimed in any claim 12 wherein the fillable or refillable cartridge includes an elongate hollow barrel, an outlet at one end of the barrel and a movable plunger located within the barrel for movement toward the outlet for expulsion of material from the barrel and away from the outlet to allow filling of the barrel with the plasticised solid feed material.14. An apparatus as claimed in a claim 13 wherein the outlet of the fillable or refillable cartridge has an attachment structure provided to allow the fillable or refillable cartridge to be releasably attached to a downstream process.15. An apparatus as claimed in any claim 12 or claim 13 wherein the plunger is hollow with an opening at a forward end thereof so that the fillable or refillable cartridge is filled with the plasticised solid feed material through the plunger.16. An apparatus as claimed in any one of claims 12 to 15 wherein an additional piston-in-cylinder ram is used to inject the plasticised solid feed material exiting the transfer path conduit into the fillable or refillable cartridge.17. An apparatus as claimed in any one of claims 12 to 16 further comprising a heater to heat. the fillable or refillable cartridge during filling.18. An apparatus as claimed in a claim 17 wherein the heater provided in more than one part to allow the more than one part to be separated to load and remove the cartridges.19. An apparatus as claimed in any one of claims 12 to 17 further comprising a mating dry break coupling is provided relative to the fillable or refillable cartridge.20. A 3D printing apparatus comprising an apparatus for forming a steady stream of plasticised solid print material as claimed in any one of the preceding claims and at least one print head wherein the plasticised solid print material is provided to at least one supply path of the 3D printing apparatus.21. A method for forming a steady stream of plasticised solid feed material, the method including the steps of: a. Introducing shredded, solid feed material to a piston-in-cylinder ram; b. Compacting the shredded, solid feed material to form a solid billet of feed material in the cylinder; c. extruding at least a portion of the solid billet from an exit end of the cylinder into a transfer path in communication with the exit end of the cylinder; d. heating the feed material in at least a portion of the transfer path to plasticise the feed material and heat the feed material to temperature to form a Iced of plasticised solid feed material.22. A method as claimed in claim 21 wherein the step of extruding forces flow of the plasticised solid feed material through the transfer path.23. A method as claimed in claim 21 or claim 22 wherein the temperature of the plasticised solid feed material remains below a melting temperature of the feed material.24. A method as claimed in claim 23 wherein, for a chocolate feed material, the temperature of the plasticised solid feed material is heated to between 23°C and 35°C by the heater.25. A method as claimed in any onc of claims 21 to 24 further comprising a step of shredding the solid feed material to a size of between lmm to 5mm beforeintroduction to the piston-in-cylinder ram.26. A method as claimed in any one of claims 21 to 25 wherein, on a down stroke of the piston, the shredded, solid feed material is initially compacted at an upper part of the cylinder. 27. 28. 29. 30. 31. 32. 33.A method as claimed in claim 26 wherein further downward movement of the piston in the cylinder compresses the compacted shredded, solid material to form a solid billet of feed material at a lower part of the cylinder.A method as claimed in any one of claims 21 to 27 wherein the billet is always present within a lower part of the cylinder.A method as claimed in any one of claims 21 to 28 wherein the billet of plasticised solid feed material undergoes axial and/or circumferential mixing in the transfer path conduit as it traverses through the transfer path conduit.A method as claimed in any one of claims 21 to 29 wherein the billet in the transfer path conduit is maintained between 23°C and 35°C.A method as claimed in any one of claims 21 to 30 comprising the further step of filling at least one fillable or refillable cartridge including an elongate hollow bard, an outlet at one end of the barrel and a movable plunger located within the barrel for movement toward the outlet for expulsion of material from the barrel and away from the outlet for filling of the barrel with the plasticised solid feed material.A method as claimed in claim 31 wherein the plunger is hollow, and the method comprises the step of filling at least one fillable or refillable cartridge through the hollow plunger.A method as claimed in either one of claims 31 or 32 comprising the further step of applying back pressure to plunger during filling to prevent air building up in the cartridge.