Device for emptying a graphite crucible

Abstract

The present disclose describes a device (100) for emptying a graphite crucible (110) containing graphite powder, the device (100) comprising a connection unit (120), a lifting assembly (220) and a tipping assembly (250) connected to the connection unit (120) and the lifting assembly (220), wherein the tipping assembly (250) is configured to rotate the connection unit (120) and the lifting assembly (220) in a vertical plane while the connection unit (120) and the lifting assembly (220) are arranged in a static position relative to one another.

Description

Device for emptying a graphite crucibleField of inventionThe present invention relates to the field of synthetic graphite manufacturing.Background

[0001] The demand for synthetic graphite has increased significantly in recent years, largely due to its use as anode material in lithium-ion batteries. The process of producing synthetic graphite from coke particles may generally be subdivided into several steps comprising a graphitization step.

[0002] One way of performing graphitization is to fill graphite crucibles with the material to be graphitized followed by heating said material to ~3000 °C in a furnace before cooling the graphite crucibles and the resulting graphite powder therein. Cooling of graphite crucibles containing graphite powder is generally performed by simply allowing the crucibles to cool naturally, optionally in an inert atmosphere. Such natural cooling of graphite crucibles containing graphite powder typically takes a several days, thus occupying the graphite crucible for a long time before said crucible is ready for being reused.

[0003] It is an aim of the present invention to provide a device and method that may be employed to reduce the time between consecutive uses of a graphite crucible for graphitization purposes.Summary of the invention

[0004] A first aspect of the present invention provides a device for emptying a graphite crucible containing graphite powder, wherein the graphite crucible comprises a graphite crucible open top and comprises a graphite crucible closed base, the device comprising: a connection unit comprising a conduit comprising a conduit first opening, a conduit second opening and a conduit wall, a first sealing element arranged around the conduit first opening, a main valve configured to close off and open the conduit, a first gas inlet arranged in fluid communication with a first part of the conduit located between the main valve and the conduit first opening, a first gas outlet arranged in fluid communication with the first part of the conduit, and a water-cooling element arranged in contact with the conduit wall, a lifting assembly comprising a base portion arranged facing the conduit first opening, and a lifting mechanism connected to the base portion and configured to move the base portion towards the conduit first opening, and a tipping assembly connected to the connection unit and the lifting assembly, wherein the tipping assembly is configured to rotate the connection unit and thelifting assembly in a vertical plane while the connection unit and the lifting assembly are arranged in a static position relative to one another.

[0005] In an embodiment of the invention the conduit is shaped as a funnel, and the conduit first opening is larger than the conduit second opening.

[0006] In another embodiment of the invention the funnel comprises at least a first and a second side wall section, where the first side wall section has a lower inclination than the second side wall section.

[0007] In yet another embodiment of the invention the device further comprises a vibrator.

[0008] In another embodiment of the invention the first sealing element is cylindrical.

[0009] In another embodiment of the invention the base portion is arranged in a first plane, the conduit first opening is arranged in a second plane, and the first plane and second plane are parallel.

[0010] In another embodiment of the invention the first sealing element and the base portion are heat resistant up to a temperature of at least 450 °C.

[0011] In another embodiment of the invention the base portion of the lifting assembly comprises a plurality of rollers, and a locking mechanism for locking each roller in place.

[0012] In another embodiment of the invention the connection unit further comprises a second sealing element arranged around the conduit second opening.

[0013] In another embodiment of the invention the main valve is a knife gate valve.

[0014] In another embodiment of the invention the cross section of the knife gate valve is of the same size or larger than the cross section of the conduit.

[0015] In another embodiment of the invention the connection unit further comprises a second gas inlet arranged in fluid communication with a second part of the conduit located between the main valve and the conduit second opening, a second gas outlet arranged in fluid communication with the second part of the conduit.

[0016] In another embodiment of the invention the tipping assembly comprises a motor and a connector, wherein the connector is connected to the connection unit, the lifting assembly, and the motor.

[0017] A second aspect of the present invention provides a method for emptying a graphite crucible containing graphite powder, wherein the graphite crucible comprises a graphite crucible open top and comprises a graphite crucible closed base, the method comprises the steps of providing a device for emptying a graphite crucible, placing the graphite crucible on the base portion, moving, by the lifting mechanism, the base portion towards the conduit first opening until the graphite crucible open top engages the first sealing element, providing, bythe lifting mechanism, a clamping force on the graphite crucible in the axial direction of the graphite crucible by forcing the graphite crucible towards the first sealing element, introducing an inert purge gas into the first part of the conduit via the first gas inlet, extracting gas from the first part of the conduit via the first gas outlet, circulating cooling water in the water-cooling element, rotating, by the tipping assembly, the connection unit, the lifting assembly and the graphite crucible in a vertical plane while the connection unit and the lifting assembly are arranged in a static position relative to one another, and opening the main valve.

[0018] In an embodiment of the invention the method further comprises a step of engaging the connection unit with an opening of a dump tank between the step of rotating the connection unit and the lifting assembly and the step of opening the main valve.Brief description of the drawings

[0019] Figure la is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where a graphite crucible is placed on a base portion of a lifting assembly of the device,

[0020] Figure lb is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where a graphite crucible is placed on a base portion of a lifting assembly of the device, and where the graphite crucible is brought into engagement with a connection unit of the device,

[0021] Figure 2 is a schematic illustration of a device for emptying a graphite crucible containing graphite powder showing a close up of a first sealing element arranged around a conduit first opening of a connection unit of the device,

[0022] Figure 3 is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where a conduit of a connection unit of the device is shaped as a funnel,

[0023] Figure 4a is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where a graphite crucible is placed on a base portion of a lifting assembly of the device, and where the base portion of the lifting assembly comprises a plurality of rollers.

[0024] Figure 4b is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where a graphite crucible is placed on a base portion of a lifting assembly of the device, where the graphite crucible is brought into engagement with a connection unit of the device, and where the base portion of the lifting assembly comprises a plurality of rollers.

[0025] Figure 5 is a schematic illustration of a device for emptying a graphite crucible containing graphite powder, where the device comprises a vibrator located in various optional positions, and

[0026] Figure 6 is a schematic illustration of a device for emptying a graphite crucible containing graphite powder showing a tipping assembly of the device rotating a connection unit and a lifting assembly of the device in a vertical plane while the connection unit and the lifting assembly are arranged in a static position relative to one another.Detailed description of the invention

[0027] In the following, general embodiments as well as particular exemplary embodiments of the invention will be described. References will be made to the accompanying drawings. It shall be noted, however, that the drawings are exemplary embodiments only, and that other features and embodiments may well be within the scope of the invention as claimed. Further, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The term "invention" may herein be used interchangeably with the term "disclosure". The term "producing" may herein be used interchangeably with the term "obtaining".

[0028] Unless otherwise defined, all terms of art, notations and other scientific terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this invention pertains. Certain terms of art, notations, and other scientific terms or terminology may, however, be defined specifically as indicated below.

[0029] The present invention provides a device 100 for emptying a graphite crucible 110 containing graphite powder, and a method employing such a device 100 for emptying a graphite crucible 110 containing graphite powder. The device 100 comprises a connection unit 120, a lifting assembly 220, and a tipping assembly 250 and the device 100 is generally configured to tip a graphite crucible 110, for example upside down, such that any graphite powder located therein may be removed from the graphite crucible 110, at least in part by means of gravity. Figures la and lb schematically illustrate an example of a device 100 for emptying a graphite crucible 110.

[0030] The device 100 for emptying a graphite crucible 110 may generally be operated by placing the graphite crucible 100 to be emptied on a base portion 230 of the lifting assembly 220 before lifting the base portion 230 by means of the lifting mechanism 240 until the graphite crucible 110 engages the connection unit 120. Once the graphite crucible 110 has engaged the connection unit 120, the liftingmechanism 240 may force the graphite crucible 110 towards the connection unit120 such that the graphite crucible 110 is clamped in place between the base portion 230 of the lifting assembly 220 and the connection unit 120. The tipping assembly 250 may then rotate the connection unit 120 and the lifting assembly 220 together with the graphite crucible 110 in a vertical plane while the connection unit 120 and the lifting assembly 220 are arranged in a static position relative to one another. Once the graphite crucible 110 has been rotated, any graphite powder in the graphite crucible 110 may be emptied out of the graphite crucible 110. The connection unit 120 may here be a connector that is configured to connect to an open top of the graphite crucible 110 and to direct the content of the graphite crucible 100 into for example a dump tank 350 once the graphite crucible 110 has been rotated. A visual representation of the operation of the device 100 may be seen for example in the figures la, lb and 6.

[0031] As schematically illustrated in figures la, lb, and 2, the graphite crucible 110 may be a cylindrical graphite crucible that comprises a graphite crucible open top, and a graphite crucible closed base. The graphite crucible may generally comprise a hollow interior that may contain graphite powder, and optionally a removable lid. The device 100 for emptying a graphite crucible 110 may thus be configured, e.g., sized and programmed, to empty a cylindrical graphite crucible that comprises a graphite crucible open top and comprises a graphite crucible closed base. As will be appreciated by a person skilled in the art, however, the device 100 for emptying a graphite crucible 110 may be configured to empty a graphite crucible 110 that has a non-cylindrical shape by making minor adjustments to the device described herein. As a way of example, the graphite crucible 100 may be an open top cylindrical graphite crucible with a diameter of 60 cm, a height of 100 cm and with a crucible wall of 4 cm, where each quantity for example may vary by +- 50%.

[0032] A connection unit 120 may, as schematically illustrated in figures la, and lb, comprise a conduit 130 comprising a conduit first opening 140, a conduit second opening 150, and a conduit wall 160. The connection unit 120 may thus for example comprise a tube, funnel, duct or similar that makes up the conduit 130, and may be configured to connect to the graphite crucible 110 and to direct graphite powder from within the graphite crucible 110 into for example a separate receptacle once the graphite crucible 110 has been rotated. The connection unit 120 may comprise a first end 121 that is configured to engage with a graphite crucible 110 such that the conduit 130 is brought into fluid communication with the graphite crucible hollow interior. Preferably, the first end121 of the connection unit 120 is configured to engage with a graphite crucible110 such that a seal is formed between the graphite crucible 110 and the connection unit 120. The connection unit 120 may for example comprise a first sealing element 170 arranged around the conduit first opening 140, i.e., at the first end 121 of the connection unit 120. Here, the first sealing element 170 may be configured to form a seal, optionally air-tight, between the connection unit 120 and the graphite crucible 110 when the graphite crucible 110 is engaged with the connection unit 120.

[0033] The lifting assembly 220 may, as schematically illustrated in figures la and lb, comprise a base portion 230 arranged facing the connection unit 120 and a lifting mechanism 240 connected to the base portion 230. More specifically, the base portion 230 may be facing the conduit first opening 140 of the connection unit 120, and the lifting mechanism 240 of the lifting assembly 220 may be configured to move the base portion 230 towards the conduit first opening 140, i.e., the first end 121 of the connection unit 120. The lifting assembly 220 may optionally be directly connected to the connection unit 120, or alternatively be indirectly connected to the connection unit 120, for example via the tipping assembly 250. The lifting mechanism 240 may for example comprise a motor or another suitable mechanism such as a hydraulic system. As will be appreciated by a person skilled in the art with knowledge of the present disclosure, the lifting mechanism 240 may be realized in a series of ways, and the lifting mechanism 240 may for example comprise one or more of a rail, gear system, power supply etc.

[0034] In operation of the device 100, a graphite crucible 110 may initially be placed on the base portion 120 of the lifting assembly 220 before being moved towards the connection unit 120 until the graphite crucible engages the connection unit 120. Once the graphite crucible 110 has engaged the connection unit 120, the lifting mechanism 240 may provide a clamping force on the graphite crucible 110 by forcing the graphite crucible 110 towards the connection unit 120. This clamping force may here be sufficiently strong to keep the graphite crucible 110 in place when the graphite crucible 110 later is rotated between 0 and 180 ° in a vertical plane. As is schematically illustrated in figures la and lb, the clamping force applied to the graphite crucible 110 may preferably be applied in the axial direction 111 of the graphite crucible 110. The latter is particularly preferable when employing a cylindrical graphite crucible with a hollow interior, as the strain from the clamping will be distributed along the length of the crucible walls. The alternative of clamping the graphite crucible 110 in the radial direction of the graphite crucible 110 is less preferable, as the latter implies an increased risk of breaking the graphite crucible 110. Preferably, the base portion 230 ofthe lifting assembly 220 is arranged in a first plane and the conduit first opening is arranged in a second plane, where the first plane and second plane are parallel. The latter configuration is preferable for enabling an even clamping force on the graphite crucible 110.

[0035] The tipping assembly 250 is as schematically illustrated in figures la, lb and 6 connected to the connection unit 120 and the lifting assembly 220 and is configured to rotate the connection unit 120 and the lifting assembly 220 in a vertical plane while the connection unit 120 and the lifting assembly 220 are arranged in a static position relative to one another. This static position between the connection unit 120 and the lifting assembly 220 enables any clamping force applied to a graphite crucible 110 to be maintained during the rotation by the tipping assembly 250 such that the graphite crucible 110 may be maintained in a fixed position relative to the connection unit 120 and lifting assembly 220. The tipping assembly 250 may, as schematically illustrated in figures la, lb and 6, comprise one or more connectors 310 that connects the connection unit 120 and the lifting assembly 220 and that maintains the static position between the connection unit 120 and the lifting assembly 220. As will be appreciated by a person skilled in the art with knowledge of the present disclosure, such a connector 310 or connectors 310 may comprise for example one or more bent girders, a series of interconnected steel bars, etc. The rotation by the tipping assembly 250 may be performed by means of a motor 300 or another suitable driving mechanism such as a hydraulic system. The tipping assembly 250 may thus in a particular example comprise a motor 300 and a connector 310 where the connector 310 is connected to the connection unit 120, the lifting assembly 220, and the motor 300.

[0036] The connection unit 120 may, as schematically illustrated in figures la and lb, comprise a main valve 180 configured to close off, and open the conduit 130. The main valve 180 may here be employed to retain the content of the graphite crucible 110 until the graphite crucible 110 has been rotated to a predetermined position by the tipping assembly 250, e.g., over a dump tank 350 or another suitable receptacle. After the graphite crucible 110 has been arranged in predetermined position, the main valve 180 may be opened, and any graphite powder may be emptied out of the graphite crucible 110 through the conduit 130 of the connection unit 120. The main valve 180 is preferably a knife gate valve that optionally may be of the same size or larger than the cross section of the conduit 130. A knife gate valve has been found to be preferable when emptying a graphite crucible 110 comprising graphite powder, as a gate knife valve i.a. has been found to limit the amount of blockage, and thus flow resistance in theconduit 130 as compared for example a butterfly valve or a ball valve. A knife gate valve that is of the same size or larger than the cross section of the conduit 130 is particularly preferable, as the latter has been found to further reduce blockage of the conduit 130 by reducing the amount of obstruction in the conduit 130.

[0037] The device for emptying a graphite crucible may according to the present invention be configured to empty a graphite crucible that has been allowed to cool for a period after having been kept at a temperature sufficient for graphitization in a graphitization furnace. The device for emptying a graphite crucible may more specifically be configured to empty a graphite crucible containing graphite powder with a temperature up to 1500 °C, optionally or additionally where the graphite crucible has a surface temperature of up to 450 °C. The lifting assembly and the connection unit may thus be specifically configured to withstand said temperatures. Graphite powder with a temperature up to 1500 °C may herein be interpreted as graphite powder where at least a part of the graphite powder has a temperature up to 1500 °C. As will be appreciated by a person skilled in the art with knowledge of the present disclosure, different parts of the graphite powder within a graphite crucible may have different temperatures dependent on the location of the part of graphite powder and that the average temperature of the graphite powder for example may be in the range 300 °C - 1000 °C or alternatively 450 °C - 800 °C. A first part of the graphite powder located close to the wall of the graphite crucible may for example be cooler than a second part of the graphite powder located more centrally in the graphite crucible.

[0038] The first sealing element 170 of the connection unit 120 may generally be a gasket, optionally configured to withstand temperatures up to at least 450 °C. The first sealing element 170 of the connection unit 120 may more specifically be a mica gasket or a stainless-steel reinforced mica gasket. A mica gasket or a stainless-steel reinforced mica gasket has been found to be preferable when emptying a graphite crucible 110 containing hot graphite powder. Many conventional gaskets such a silicone or rubber gaskets have been found less suitable for sustaining elevated temperatures. The first sealing element 170 may optionally or additionally comprise a plurality of sections, for example to ease replacement due to wear over time that may be caused by contact with hot graphite crucibles. The first sealing element 170 may be circular, i.e., cylindrical, which may be preferable if the graphite crucible to be emptied is cylindrical. The first sealing element 170 may thus have the same diameter as a cylindrical graphite crucible, e.g., the same diameter as the diameter measured at thecentre of the wall of the cylindrical graphite crucible. The base portion 230 of the lifting assembly 220 is preferably arranged in a first plane and the conduit first opening 140 is arranged in a second plane, where the first plane and second plane are parallel. The latter configuration is preferable for obtaining an even seal along the whole of the first sealing surface. The connection unit 120 may, as schematically illustrated in figure 2, further comprise a recess 320 arranged around the conduit first opening 140 for receiving the first sealing element 170. Such a recess 320 has been found to be preferable for improving the seal obtained by the first sealing element 170, and also in order to maintain the first sealing element 170 in place.

[0039] The connection unit 120 comprises as schematically illustrated in figures la and lb a first gas inlet 190 and a first gas outlet 200, where the first gas inlet 190 and the first gas outlet 200 are arranged in fluid communication with a first part of the conduit located between the main valve 180 and the conduit first opening 140. The first gas inlet 190 may here be employed to introduce an inert gas into the first part of the conduit 130, whereas the first gas outlet 200 may be employed to extract gas from the first part of the conduit 130. The first gas inlet 190 and the first gas outlet 200 may thus be employed in order to purge the first part of the conduit 130, for example in order to purge the first part of the conduit 130 of any oxygen. The first gas inlet 190 and first gas outlet 200 may in other words be employed in order to reduce any oxidation of any graphite powder during emptying of the graphite crucible 110, particularly as the graphite crucible 110 is tipped and any graphite powder located therein is stirred up. The first gas inlet 190 and the first gas outlet 200 may each comprise a valve and one or more gas connectors for being connected to a suitable gas supply and gas extraction line / exhaust respectively.

[0040] The first gas inlet 190 may optionally be employed in order to fluidize any graphite powder in a graphite crucible 110 once the graphite crucible 110 has been rotated by the device 100. Once the graphite crucible 110 has been rotated, any purging has been performed, and the main valve 180 is opened, gas may be introduced through the first gas inlet 190 in order to fluidize the graphite powder in the graphite crucible 110 such that the graphite powder flows more easily out of the graphite crucible 110. The connection unit 120 may optionally be provided with an additional gas inlet 360, where said additional gas inlet 360 may be configured to be employed for fluidizing any graphite powder in a graphite crucible 110 once the graphite crucible 110 has been rotated by the device 100. The additional gas inlet 360 may for example be shaped to direct gas flow towards the inner side of the graphite crucible base. Figure 5schematically illustrates a device for emptying a graphite crucible 110, where the device 100 comprises a connection unit 120 that comprises an additional gas inlet 360.

[0041] The connection unit 120 may further comprise a water-cooling element 210 arranged in, or in contact with the conduit wall 160, directly or indirectly. The water-cooling element 210 may here be configured to cool the connection unit 120, or more specifically the conduit wall 160, which may be preferable when emptying a graphite crucible 110 containing graphite powder with an elevated temperature. The water-cooling element 170 may here generally be a water conduit in thermal communication with, e.g., in physical contact with, the conduit wall 160. The water-cooling element 210 may, as schematically illustrated in figures la and lb, for example be a pipe, or alternatively be a jacket element embedded in or surrounding the connection unit 120. The watercooling element 210 may, as will be appreciated by a person skilled in the art, be connected to a water inlet and a water outlet. As will further be appreciated by a person skilled in the art, the water-cooling element 210 may alternatively be employed to use another cooling medium than water, e.g., oil, glycol, or air. The water-cooling element 210 may further be arranged in contact with the main valve 180 and may be configured to cool the main valve 180, preferably at least the part of the main valve 180 that may be brought in contact with graphite powder, e.g., at least a knife blade of a knife gate valve.

[0042] The device 100 for emptying a graphite crucible 110 may, as schematically illustrated in figure 6, be configured to empty the graphite crucible 110 into a dump tank 350 or another form of suitable receptacle. A dump tank 350 may here be a receptable configured to store and cool graphite powder, and optionally be configured to be maintained under an inert atmosphere. The connection unit 120 may thus be configured to connect to a dump tank 350, e.g., by being provided with suitable means for being connected to a dump tank 350. The connection unit 120 may for example comprise a second sealing element 290 arranged around the conduit second opening 150, where the second sealing element 290 for example may be employed to make a seal with an inlet of dump tank 350 when the connection unit 120 engages with a such. The second sealing element 290 may generally be of the same or different type as the first sealing element 170, and the second sealing element 290 may thus optionally be configured in any one or more of the same ways as the first sealing element 170 described above.

[0043] As schematically illustrated in figures la and lb, the connection unit 120 may further comprise a second gas inlet 330 arranged in fluid communication with asecond part of the conduit 160 located between the main valve 180 and the conduit second opening 150, and a second gas outlet 340 arranged in fluid communication with the second part of the conduit. The second gas inlet 330 may here be employed to introduce an inert gas into the second part of the conduit, whereas the second gas outlet 340 may be employed to extract gas from the second part of the conduit. The second gas inlet 330 and the second gas outlet 340 may thus be employed in order to purge the second part of the conduit, for example to purge the second part of the conduit of any oxygen. The second gas inlet 330 and second gas outlet 340 may thus be employed in order to reduce any oxidation of any graphite powder being emptied into a dump tank 350. Any oxygen located in the second part of the conduit after the connection unit has been engaged with the dump tank 350 may thus be removed, and based on the configuration of the dump tank 350, the second gas inlet 330 and second gas outlet 340 may optionally be employed to purge the dump tank 350 itself. The second gas inlet 330 and the second gas outlet 340 may each particularly comprise a valve and one or more gas connectors for being connected to a suitable gas supply and gas extraction line / exhaus respectively.

[0044] As schematically illustrated in figure 3, the conduit 130 of the connection unit 120 may be shaped as a funnel 260. Here, the conduit first opening 140 may be larger than the conduit second opening 150, or alternatively, the conduit second opening 150 may be larger than the conduit first opening 140. A funnel shaped conduit is generally preferable when the opening of the dump tank 350 for emptying any content of the graphite crucible 110 into has a smaller or larger opening than the graphite crucible 110. A funnel shaped conduit where the conduit first opening 140 is larger than the conduit second opening 150 is particularly preferable as such a configuration has been found to reduce dust formation and hence reduce the time necessary to empty a graphite crucible 110.

[0045] As schematically illustrated in figure 3, the conduit 130 of the connection unit 120 may be shaped as an eccentric funnel. More generally, the conduit 130 of the connection unit 120 may be shaped as a funnel 260 that comprises at least a first and a second side wall section, where the first side wall section has a lower inclination than the second side wall section. The latter has been found to be preferable in order to reduce friction between the funnel 260 and the graphite powder to be emptied and to reduce blockage of the funnel 260. The time for emptying a graphite crucible 110 of graphite powder may thus further be reduced as compared to a symmetric funnel.

[0046] As schematically illustrated in figure 5, the device 100 for emptying a graphite crucible 110 may further comprise a vibrator 270. The vibrator 270 may be arranged for example in direct or indirect contact with the connection unit 120, the lifting assembly 220 or the tipping assembly 250. The vibrator 270 may be employed in order to shake up the graphite powder to be emptied, and thus enable improved flow of graphite powder out of the graphite crucible 110. As will be appreciated by a person skilled in the art, a vibrator 270 may generally be connected to any part of the device 100 for emptying a graphite crucible as long as vibrations may be transferred to the graphite powder to be emptied.

[0047] The base portion 230 of the lifting assembly 220 may generally be configured to receive a graphite crucible 110 comprising graphite powder, where the surface of the graphite crucible 110 may have a temperature up to 450 °C, or alternatively above 450 °C. The base portion 230 may for example be made of a suitable material such as steel. A softer steel is generally preferable to a harder steel in order to limit wear of the graphite crucible 110, and the base portion 230 may thus preferably be made of carbon steel, for example spheroidized or fully annealed steel. The base portion 230 may, as schematically illustrated in figures 4a and 4b be aligned with a conveyor-based transport system for graphite crucibles that may be employed in order to limit wear on the graphite crucibles to be emptied. The base portion of the lifting assembly 220 may thus generally be configured to slidingly receive a graphite crucible 110, i.e., be configured such that a graphite crucible 110 may be slid onto the base portion 230. The base portion 230 may for example comprise a plurality of rollers 280, e.g., cylinders that are rotatable. The graphite crucible 110 may then be rolled onto the base portion 230 of the lifting assembly 220, e.g., from a conveyer system. The rollers 280 may here be provided with a locking mechanism 281, where the locking mechanism 281 may be configured to lock one or more of the rollers 280 in place and prevent it from rotating. The locking mechanism 280 may for example comprise one or more locking pins, and / or breaks.

[0048] The present invention further provides a method for emptying a graphite crucible containing graphite powder, wherein the method employs the device for emptying a graphite crucible. The graphite crucible is here preferably a graphite crucible that is cylindrical, which comprises a graphite crucible open top, and a graphite crucible closed base. The method for emptying a graphite crucible containing graphite powder involves more specifically the employment of the device for emptying a graphite crucible in order to rotate a graphite crucible in the vertical plane so that any graphite powder inside the graphite crucible may be removed from the graphite crucible.

[0049] The method comprises an initial step of placing the graphite crucible on the base portion of the lifting assembly of the device followed by a step of moving, by the lifting mechanism, the base portion towards the conduit first opening until graphite crucible open top engages the connection unit. Upon engagement the graphite crucible may form an airtight seal with the connection unit, thereby providing a fluid communication between the graphite crucible interior and the conduit of the connection unit. The engagement between the graphite crucible open top and the connection unit may here preferably be between the graphite crucible open top and the first sealing element of the connection unit.

[0050] After the graphite crucible has engaged the connection unit, the lifting mechanism may provide a force, i.e., a clamping force on the graphite crucible in the axial direction of the graphite crucible by forcing the graphite crucible towards the first sealing element. The seal between the connection unit and the graphite crucible may then be increased, and the graphite crucible may, due to this clamping force, be held in place between the base portion of the lifting assembly and the connection unit. The connection unit and the lifting assembly may be connected to each other by for example the tipping assembly but may alternatively or optionally be connected to each other by a separate connection element / connector, or alternatively by a plurality of separate interconnected connection elements. When the lifting assembly forces the graphite crucible towards the first sealing element the connection between the connection unit and the lifting assembly may thus stop the connection unit from moving such that clamping of the graphite crucible may be obtained.

[0051] After the graphite crucible has been clamped between the base portion of the lifting assembly and the connection unit, the first part of the conduit of the connection unit may be purged using an inert purge gas. An inert purge gas may be introduced into the first part of the conduit via the first gas inlet, and gas may be extracted from the first part of the conduit via the first gas outlet. The purging may continue until a predetermined oxygen concentration is obtained in the first part of the conduit of the connection unit such that oxidation of the graphite powder in the graphite crucible may be limited to predetermined level.

[0052] Before rotating the graphite crucible in a vertical plane, cooling water may be circulated in the water-cooling element. The water-cooling may for example be performed for a non-zero period, e.g., at least ~10 seconds, before rotating the graphite crucible in a vertical plane such that the conduit wall, and optionally the main valve of the connection unit may be cooled prior to being exposed to the graphite powder.

[0053] After purging and water-cooling has been initiated, the tipping assembly may then rotate the connection unit, the lifting assembly and the graphite crucible in a vertical plane while the connection unit and the lifting assembly are arranged in a static position relative to one another. The clamping force between the lifting assembly, the graphite crucible and the connection unit will here hold the graphite crucible in place so that it remains in a fixed position between the connection unit and the base portion of the lifting assembly.

[0054] Once the connection unit, the lifting assembly and the graphite crucible has been rotated in a vertical plane, for example such that the graphite crucible has been rotated more than 90 °, preferably 180 °, the main valve may be opened and the graphite powder inside the graphite crucible may be removed from the graphite crucible. The connection unit may optionally be engaged with an opening of a dump tank or similar before the main valve is opened. The second part of the conduit of the connection unit may additionally be purged prior to opening the main valve.

[0055] The terms "tip" and "rotate", and the terms "rotating", and "tipping" may herein generally be used interchangeably to refer to the action of rotating a graphite crucible in a vertical plane, optionally at least 90 °. The tipping assembly may thus alternatively be termed a rotation assembly.

Claims

Claims1. A device (100) for emptying a graphite crucible (110) containing graphite powder, wherein the graphite crucible (110) comprises a graphite crucible open top and comprises a graphite crucible closed base, the device (100) comprising: a connection unit (120) comprising a conduit (130) comprising a conduit first opening (140), a conduit second opening (150) and a conduit wall (160), a first sealing element (170) arranged around the conduit first opening (140), a main valve (180) configured to close off and open the conduit (130), a first gas inlet (190) arranged in fluid communication with a first part of the conduit located between the main valve (180) and the conduit first opening (140), a first gas outlet (200) arranged in fluid communication with the first part of the conduit, and a water-cooling element (210) arranged in contact with the conduit wall (160), a lifting assembly (220) comprising a base portion (230) arranged facing the conduit first opening (140), and a lifting mechanism (240) connected to the base portion (230) and configured to move the base portion (230) towards the conduit first opening (140), and a tipping assembly (250) connected to the connection unit (120) and the lifting assembly (220), wherein the tipping assembly (250) is configured to rotate the connection unit (120) and the lifting assembly (220) in a vertical plane while the connection unit (120) and the lifting assembly (220) are arranged in a static position relative to one another.

2. The device (100) according to claim 1, wherein the conduit (130) is shaped as a funnel (260), and wherein the conduit first opening (140) is larger than the conduit second opening (150).

3. The device (100) according to claim 2, where the funnel (260) comprises at least a first and a second side wall section, where the first side wall section has a lower inclination than the second side wall section.

4. The device (100) according to any one of the previous claims, further comprising a vibrator (270).

5. The device (100) according to any one of the previous claims, wherein the first sealing element (170) is cylindrical.

6. The device (100) according to any one of the previous claims, wherein the base portion (230) is arranged in a first plane, the conduit first opening (140) is arranged in a second plane, and the first plane and second plane are parallel.

7. The device (100) according to any one of the previous claims, wherein the first sealing element (170) and the base portion (230) are heat resistant up to a temperature of at least 450 °C.

8. The device (100) according to any one of the previous claims, wherein the base portion (230) of the lifting assembly (220) comprises a plurality of rollers (280), and a locking mechanism for locking each roller (280) in place.

9. The device (100) according to any one of the previous claims, wherein the connection unit (120) further comprises a second sealing element (290) arranged around the conduit second opening (150).

10. The device (100) according to any one of the previous claims, wherein main valve (180) is a knife gate valve.

11. The device (100) according to claim 10, wherein the cross section of the knife gate valve is of the same size or larger than the cross section of the conduit.

12. The device (100) according to any one of the previous claims, wherein the connection unit (120) further comprises a second gas inlet (330) arranged in fluid communication with a second part of the conduit located between the main valve (180) and the conduit second opening (150), a second gas outlet (340) arranged in fluid communication with the second part of the conduit.

13. The device (100) according to any one of the previous claims, wherein the tipping assembly (250) comprises a motor (300) and a connector (310), wherein theconnector (310) is connected to the connection unit (120), the lifting assembly (220), and the motor (300).

14. A method for emptying a graphite crucible (110) containing graphite powder, wherein the graphite crucible (110) comprises a graphite crucible open top and comprises a graphite crucible closed base, the method comprises the steps of providing a device (100) according to any one of the claims 1 - 13, placing the graphite crucible (110) on the base portion (230), moving, by the lifting mechanism (240), the base portion (230) towards the conduit first opening (140) until the graphite crucible open top engages the first sealing element (170), providing, by the lifting mechanism (240), a clamping force on the graphite crucible (110) in the axial direction of the graphite crucible (110) by forcing the graphite crucible (110) towards the first sealing element (170), introducing an inert purge gas into the first part of the conduit (130) via the first gas inlet (190), extracting gas from the first part of the conduit (130) via the first gas outlet (200), circulating cooling water in the water-cooling element (210), rotating, by the tipping assembly (250), the connection unit, the lifting assembly (220) and the graphite crucible (110) in a vertical plane while the connection unit and the lifting assembly (220) are arranged in a static position relative to one another, and opening the main valve (180).

15. The method according to claim 14, further comprising a step of engaging the connection unit with an opening of a dump tank (350) between the step of rotating the connection unit and the lifting assembly (220) and the step of opening the main valve (180).

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