NO20231123A1 - Crucible cleaning device and method of cleaning residues from an inside of cruciple - Google Patents

Description

CRUCIBLE CLEANING DEVICE

TECHNICAL FIELD

The invention relates to a device for cleaning residues from a crucible.

BACKGROUND

Crucibles are used for transporting molten metals, such as aluminum, at elevated temperatures. A crucible is a cylindrical container with or without additional lid, such that the material to be transferred can easily be placed inside the container. The molten metal may then either be poured or by pressure discharged into a mold, furnace etc., or otherwise utilized. When a crucible has been used for transferring molten metal, residues from the metal are left in the crucible. The residues occupy space within the crucible and may negatively affect the performance of the crucible (metal yield), and so the residues must be removed at regular intervals to optimize the metal transfer. Crucibles as described herein are for industrial use and may accommodate up to 1m<3 >of molten metal, or more.

Different devices for cleaning residues from crucibles exist, but these devices are mainly large, bulky, and very energy inefficient. Known devices for cleaning crucibles may comprise a small rotatable cleaning head that is guided in a circular manner around the inside of the crucible, usually by means of rotating the crucible. The rotating cleaning head grinds the residues into debris. As the cleaning head is guided upwards, the circumference of the inside of the crucible is cleaned. As the circumference is cleaned, the cleaning head is guided further into the crucible, until the bottom of the crucible is clean. The crucible is in most cases positioned upside down in such machines. Such a device requires considerable power for rotating the heavy crucible in addition to powering the rotating head that is movable in minimum two directions within the crucible. This requires tough, mechanical parts and the devices are both large and energy-consuming.

Other devices for cleaning residues from crucibles may comprise a full profile cleaning head. A full profile cleaning head is a cleaning head having a diameter spanning the inside diameter of the crucible to be cleaned. The cleaning head may as such not be guided in a circular manner around the inside of the crucible, but the rotation axis of the cleaning head may instead coincide with a center axis of the cylindrical crucible. Because of the weight and size of these devices, the rotation axis of the cleaning head is horizontal or near horizontal, to allow the grinded residues to escape the crucible. A full profile cleaning head commonly comprise a helix element to convey the debris out of the crucible. The crucible is held stationary in the device, and the cleaning head is fed into the crucible.

Crucibles are heavy, and securing a crucible containing residues at an angle requires structurally strong, and thus heavy, equipment. The equipment must also withstand the impact and vibrations from the rotating cleaning head. Known devices for cleaning crucibles commonly include hydraulic systems, which are tough and reliable, but expensive to both install and run. Hydraulic systems are also slow in response. Known devices are less adaptable to crucibles of different sizes, i.e. inner diameter and depth, and are very little energy efficient. Commonly known devices for cleaning residues from a crucible comprise a motor and a cleaning head that run at a fixed speed and a cleaning cycle that takes a fixed amount of time, regardless of the amount of residue in the crucible. Such known devices are therefore oversized and overpowered for most of the work they perform, and are not very adaptable. Known devices for cleaning residues from crucibles are also very loud due to the movement of heavy parts and the pneumatic and hydraulic operation.

There is therefore a need for an improved device for cleaning residues from a crucible to reduce or eliminate the above mentioned disadvantages of known techniques. It is an objective of the invention to achieve this and to provide further advantages over the state of the art.

SUMMARY OF THE INVENTION

It is an object of the invention to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problem.

According to a first aspect, there is provided a crucible cleaning device, comprising:

a cleaning head rotatably controlled about a vertical axis for cleaning residues from a crucible comprising a brim and a bottom;

a crucible retaining element for mating with the crucible and fixing the crucible with the brim positioned below the bottom such that a centre axis of the crucible coincides with the vertical axis;

the crucible retaining element comprising releasable locking means for fixing the crucible to the crucible retaining element and preventing rotation and movement of the crucible in a horizontal plane;

the crucible retaining element is connected to at least one vertical control device for controlling the crucible retaining element and the crucible along the vertical axis to lower the crucible onto the cleaning head and raising the crucible from the cleaning head.

According to an embodiment, the cleaning head is vertically connected to a motor for controlling the rotation of the cleaning head.

According to an embodiment, the motor is controlled by torque monitoring. According to an embodiment, the crucible cleaning device comprises a debris collector positioned below the cleaning head and above the motor.

According to an embodiment, the crucible retaining element comprises horizontal support elements connected to vertical guide elements for preventing movement in a horizontal plane.

According to an embodiment, the crucible retaining element comprises a flange for mating with the brim of the crucible.

According to an embodiment, the at least one vertical control device is connected to the crucible retaining element by a vertical translation element.

According to an embodiment, the at least one vertical control device is a servo motor and the vertical translation element is a trapezoid screw.

According to an embodiment, the cleaning head comprises a plurality of replaceable fixed bits provided on a base.

According to an embodiment, a plurality of the fixed bits protrude from the base in a radial direction from the vertical axis, forming a gap between the base and tips of the fixed bits.

According to an embodiment, the base comprises openings for passing of residues from above the base to below the base.

According to an embodiment, the releasable locking means comprises a clamp controlled by an electric motor.

According to an embodiment, the crucible cleaning device comprises vertically extending panels to form a generally closed housing when the crucible is mated with the crucible retaining element to cover an upper part of the crucible cleaning device.

According to second aspect, there is provided a method of cleaning residues from an inside of a crucible with a crucible cleaning device, comprising the steps of:

mating the crucible on a crucible retaining element of the crucible cleaning device;

fixing the crucible to the crucible retaining element;

rotating a cleaning head;

lowering the crucible retaining element and the crucible along a vertical axis onto the cleaning head until the crucible is clean;

raising the crucible retaining element and the crucible;

releasing the crucible from the crucible retaining element;

removing the crucible from the crucible cleaning device.

According to an embodiment, the speed of lowering the crucible retaining element and the crucible is controlled by the amount of torque on the motor.

BRIEF DESCRIPTION OF THE FIGURES

The aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying figures. The figures are provided to illustrate the general structures of the invention. Like reference numerals refer to like elements throughout.

Fig. 1 shows an isometric view of an embodiment of a crucible cleaning device with a crucible.

Fig. 2 shows an isometric exploded view of the crucible cleaning device. Fig. 3a shows a section view through the crucible cleaning device with a crucible in an upper position.

Fig. 3b shows a section view through the crucible cleaning device with a crucible in a lower position.

DETAILED DESCRIPTION

The invention will now be described with reference to the accompanying figures, in which preferred example embodiments of the invention are shown. The invention may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the invention to the skilled person.

It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an" and "the" are intended to mean that there are one or more of the elements or steps unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

Referring initially to figure 1 and figure 2, figure 1 shows an embodiment of a crucible cleaning device 1 with a crucible 2 installed, and figure 2 shows the crucible cleaning device 1 in an exploded view. The crucible cleaning device 1 comprises a cleaning head 3, rotatable about a vertical axis Z. The vertical axis Z may be generally vertical, i.e. the axis may deviate from a vertical axis by some degrees. The vertical axis Z is closer to a truly vertical axis than a truly horizontal axis. The cleaning head 3 is stationary relative to the crucible cleaning device 1, i.e. it may rotate about the vertical axis Z but is fixed from moving in any directions. The cleaning head 3 is a full profile cleaning head, i.e. the diameter of the cleaning head 3 corresponds to the inner cleaning diameter of the crucible 2. The inner cleaning diameter is the diameter of a clean crucible, which may vary from the actual inner diameter of a new crucible. As is known in the art, a full profile cleaning head typically has a clearing of 8-10 mm from the inner circumference of a crucible, in order to avoid damaging the crucible.

The cleaning head 3 comprises a base 4 and a plurality of replaceable fixed bits 5. The base 4 may comprise a generally horizontal base, onto which the fixed bits 5 are replaceable provided. The fixed bits 5 may as such be replaced, but they are fixed when installed on the base 4. The fixed bits 5 are prone to wear and tear, and a horizontal base 4 provides easy replacement and attachment of new fixed bits 5. The fixed bits 5 are stationary provided on the base 4 to reduce the amount of moving parts and ensure longevity. A fixed bit 5 may e.g. be secured to the base 4 by a screw-connection. The fixed bits 5 comprise tips 6 to grind the residues inside the crucible 2 into debris that are easily removed. The tips 6 may be sharp and comprise carbide.

Fixed bits 5 protrude in an upwards direction from the base 4, i.e. in a direction generally along the vertical axis Z. However, a fixed bit 5 may deviate from the vertical axis Z by several degrees. The fixed bits 5 are distributed on the base 4 such that when the cleaning head 3 rotates, the tips 6 of the fixed bits 5 are distributed evenly across the diameter of the cleaning head 3. A plurality of fixed bits 5 may also protrude from the side of the base 4, i.e. in a generally radial direction from the vertical axis Z. The tips 6 are thus provided a distance away from the base 4 in a radial direction from the vertical axis Z. A gap is thus formed between the outer diameter of the base 4 and the inner diameter of the crucible 2 when the cleaning head 3 is inside the crucible 2. This gap allows debris to easily escape the inside of the crucible 2 past the cleaning head 3.

The base 4 may further comprise openings 7. The openings 7 extend through the base 4, and reduce the amount of material on the base 4. The openings 7 further allow debris to escape the inside of the crucible 2 past the cleaning head 3. The openings 7 may be provided on a horizontal portion of the base 4. As illustrated in figure 3a and 3b, the openings 7 may also be provided on an undercarriage of the base 4. The openings 7 on the undercarriage of the base 4 reduce air resistance as the cleaning head 3 rotates, and reduces the impact on the downwards flow of dust and debris.

The crucible cleaning device 1 further comprises a motor 8. The motor 8 controls the rotation of the cleaning head 3, such as speed and torque. The motor 8 is preferably an electric motor, and more preferably an electric variable speed motor. Being able to vary the speed allows the rotation of the cleaning head 3 to be adapted to the amount of residues in the crucible 2. The more residues, the more friction, and the rotational speed of the cleaning head 3 may e.g. be increased. For crucibles 2 with less residues, the speed may be reduced, and both energy and wear and tear on the equipment is reduced. The cleaning head 3 is preferably vertically connected to the motor 8, and the motor 8 is thus provided below the cleaning head 3. Such a vertically connected crucible cleaning device 1 can be made very compact and allows for a small footprint. It is also very energy efficient due to the use of gravity for lowering the crucible 2 onto the cleaning head 3. The motor 8 is preferably controlled by torque monitoring, as further described with reference to figure 3a and 3b.

The motor 8 is connected to the cleaning head 3 by a connection assembly 9. The connection assembly 9 transfers rotational forces from the motor 8 to the cleaning head 3, and may comprise a sub frame comprising axels and gears for supporting and transferring the rotational forces. The connection assembly 9 may in an embodiment comprise a reduction gear, and may also comprise one or more axial bearings. Great forces are at work when a rotating cleaning head 3 mills out residues from a crucible 2, but because the cleaning head 3, motor 8 and connection assembly 9 are stationary in space (i.e. not moving relative to another), an assembly comprising the cleaning head 3, motor 8 and optionally the connection assembly 9 can be made very robust and with few parts.

The crucible cleaning device 1 further comprises a crucible retaining element 10. The crucible retaining element 10 retains the crucible 2 and prevents movement of the crucible 2 relative to the crucible retaining element 10. The crucible retaining element 10 is fixed in a horizontal plane XY, such that it is prevented from movement in the horizontal plane XY, and also prevented from rotation in the horizontal plane XY. The horizontal plane XY may be generally horizontal, i.e. the plane may deviate from a truly horizontal plane by some degrees. The horizontal plane XY is perpendicular to the vertical axis Z, and should be level enough to support a crucible 2 even if the crucible 2 is not fixed to the crucible retaining element 10. The crucible retaining element 10 mates with the crucible 2 and retains it such that a longitudinal axis C of the cylindrical crucible 2 coincides with the vertical axis Z of the cleaning head 3. The crucible retaining element 10 is in the illustrated embodiment a circular element comprising a circular flange 11, such that a centre axis extending normally to the crucible retaining element 10 is also coincident with the vertical axis Z.

The crucible retaining element 10 is configured for mating with the brim 27 of a crucible 2, as illustrated in figure 1. More particularly, the flange 11 of the crucible retaining element 10 is configured for mating with the brim 27 of the crucible 2. The brim 27 may also comprise connection means for a lid (not illustrated), if a crucible 2 comprises a lid. Further, the brim 27 may comprise e.g. a spout (not illustrated), for facilitating pouring the molten metal out of the crucible 2. The crucible 2 may rest on the circular flange 11, and the crucible retaining element 10 may be formed such that the crucible 2 is centred onto the crucible retaining element 10. The longitudinal axis C of the crucible 2 is thus coincident with the vertical axis Z of the cleaning head 3. The crucible retaining element 10 may comprise an outer flange 12 protruding upwards, further providing support and easy mating of the crucible 2 to the crucible retaining element 10.

The crucible retaining element 10 may comprise horizontal support elements 13. The horizontal support elements 13 are configured to interact with vertical guide elements 14, and thus prevent horizontal movement and rotation of the crucible retaining element 10. The horizontal support elements 13 may preferably be lowfriction elements such as bearings or wheels, but may in more simpler embodiments be a pin, a guiding ring or similar. The horizontal support elements 13 may form part of the crucible retaining element 10, or may be screwed, welded or otherwise connected to the crucible retaining element 10. The vertical guide elements 14 may be posts or rails configured to interact with bearings or wheels, but may also be slots or tracks if they are part of a structure serving other functions.

The vertical guide elements 14 are fixed, and may be part of, or supported by, a frame 15. The crucible cleaning device 1 may comprise a frame 15 as a structural element, and the vertical guide elements 14 may be provided on the frame 15, or as part of the frame 15. The motor 8 may also be connected or fixed to the frame 15. The vertical guide elements 14 provide compact, stable and low-friction guiding of the crucible retaining element 10 along the vertical axis Z.

The horizontal support elements 13 and vertical guide elements 14 may be provided in pairs, preferably equally spaced around the crucible retaining element 10. Preferably, a crucible cleaning device 1 comprises at least three horizontal support elements 13 and corresponding vertical guide elements 14. In a preferred embodiment a crucible cleaning device 1 comprises four horizontal support elements 13 and four vertical guide elements 14. The frame 15 may be a generally square or rectangular frame, and a vertical guide element 14 may be provided in each corner of the frame 15. As the horizontal support elements 13 are connected to the vertical guide elements 14, movement or rotation of the crucible retaining element 10 is prevented in the horizontal plane XY, but the crucible retaining element 10 is allowed to be controlled in the vertical direction Z.

To mate the brim 27 of a crucible with the crucible retaining element 10, the crucible 2 must thus be turned upside-down (i.e. with the bottom portion 28 of the crucible 2 in an upper position, and the brim 27 of the crucible 2 in a lower position) and positioned onto the crucible retaining element 10. The crucible 2 may be lifted onto the crucible cleaning device 1 with a forklift, a crane or similar hoisting means. As illustrated in figure 1, a crucible 2 may comprise openings 16 on e.g. the bottom portion 28 for engagement with the forks of a forklift.

The crucible retaining element 10 comprises releasable locking means 17 for fixing the crucible 2 to the crucible retaining element 10. When the crucible 2 is fixed to the crucible retaining element 10, the crucible 2 is thus prevented from rotation and movement relative to the crucible retaining element 10. The releasable locking means 17 may be any means known in the art of releasably locking two flanges together, but may in a preferred embodiment comprise a clamp. The releasable locking means 17 may further comprise an electric motor 18 controlling the clamp. Electric motors 18 are small, efficient and exert precise control. The electric motor 18 may be a servomotor. Servomotors connected to clamps provide a firm grip, and locking and releasing the crucible 2 may be remotely controlled.

The crucible retaining element 10 is controllable in a direction along the vertical axis Z, normal to the horizontal plane XY. The crucible retaining element 10 may be connected to at least one vertical control device 19, for controlled lowering and raising of the crucible retaining element 10 generally along the vertical axis Z. In a preferred embodiment, the crucible retaining element 10 is connected to at least two vertical control devices 19.

Preferably, the vertical control device 19 is an electric motor. Electric motors such as servo motors are very responsive, and enables great control and synchronisation of the vertical movement of the crucible retaining element 10. The crucible retaining element 10 is preferably connected to at least two vertical control devices 19, as in the illustrated embodiment. The at least two vertical control devices 19 are synchronized for full control of the lowering and raising. Preferably, the vertical control devices 19 are equally spaced around the crucible retaining element 10. The vertical control devices 19 may also be fixed to the frame 15. The vertical control devices 19 are preferably servo motors, allowing accurate control of the vertical movement of the crucible retaining element 10. If an abnormal behaviour is detected, such as a sudden increase in the torque in the motor 8, a servo motor may immediately halt the lowering of the crucible retaining element 10, slow the movement down or slightly lift it again.

The vertical control devices 19 may be connected to the crucible retaining element 10 by vertical translation elements 20. The vertical translation elements 20 convey vertical action from the vertical control devices 19 to the crucible retaining element 10, such that the crucible retaining element 10 is moved steadily up or down. The vertical control devices 19 may as such be positioned a distance away from the crucible retaining element 10, while the vertical translation elements 20 allow for sufficient vertical movement of the crucible retaining element 10. The vertical translation elements 20 may be trapezoid screws which provides great precision in vertical translation. The vertical translation elements 20 thus enables the vertical control devices 19 to be less powerful, and thus require less energy, while still being able to precisely control the lowering and raising of the crucible retaining element 10 and the crucible 2. The vertical translation elements 20 thus enable a heavy mass to be lifted and lowered by relatively little energy input, and also provides fine adjustment of the vertical movement of the crucible retaining element 10 and crucible 2.

The crucible cleaning device 1 may further comprise a debris collector 21. The debris collector 21 is positioned below the cleaning head 3, and may preferably be positioned above the motor 8, as the motor 8 is vertically connected to the cleaning head 3. A portion of the connection assembly 9 may extend through the debris collector 21. The debris collector 21 thus covers the motor 8 and collects debris falling downwards, and not only prevents debris, dust, etc. from contaminating the motor 8, but also collects it. The debris collector 21 may comprise a raised portion 22 to also cover most of the connection assembly 9. The sloped sides of the raised portion 22 may also allow debris to collect at the bottom of the debris collector 21. The bottom of the debris collector 21 may be slightly angled and may be connected to a debris bin 23 for collection of debris and dust. As the cleaning head 3 rotates and mills debris from the crucible 2, shaking and vibrations occur. These vibrations also affect the debris collector 21, and contributes to guiding dust and debris from the debris collector 21 to the debris bin 23.

The crucible cleaning device 1 may comprise vertically extending panels 24, and the debris collector 21 may extend through the vertically extended panels 24. The debris bin 23 may as such be positioned on the outside of the vertically extending panels 24, and may be a separate element from the crucible cleaning device 1. The vertically extending panels 24 may encompass the crucible cleaning device 1, and may preferably be connected to the frame 15.

As previously discussed, the frame 15 may be generally square or rectangular, and thus comprise four vertical sides. In the illustrated embodiment, the vertically extending panels 24 covers four vertical sides. As illustrated in figure 1, when a crucible 2 is mated with the crucible retaining element 10, the crucible 2 may generally cover the upper part of the crucible cleaning device 1. As such, a generally closed space may thus be formed within the vertically extending panels 24 and the crucible 2. Such a closed space protects the environment from debris and dust. The vertically extending panels 24 may also physically protect the environment from the moving parts inside the crucible cleaning device 1, and also act as noise dampening.

The vertically extending panels 24 may also comprise a suction vent 25. The suction vent 25 allows for the creation of a slight under-pressure inside the generally closed housing formed by the vertically extending panels 24 and crucible 2. An under-pressure prevents dust and fine particles from escaping the crucible cleaning device 1. Even fumes emerging from the crucible cleaning device 1 may be drastically reduced by such a suction vent 25. Because of the low volume inside the vertically extending panels 24 and crucible 2, a sufficient under-pressure is easy and energy-efficient to achieve. The suction vent 25 may be connected to a suction pump, a bag house, or other means known in the art of creating an under-pressure for cleaning the air.

Referring now to figures 3a and 3b, the crucible cleaning device 1 is shown with the crucible 2 fixed in an upside-down position to the crucible retaining element 10. Figure 3a shows the crucible retaining element 10 in a first position, where the crucible retaining element 10 is in an upper position, and figure 3b shows the crucible retaining element 10 in a second position, where the crucible retaining element 10 is in a lower position. The crucible retaining element 10 may in the first position be positioned at the level of the top of the cleaning head 3, or slightly above. A crucible 2 positioned on the crucible retaining element 10 will thus not be in contact with the cleaning head 3 before the crucible retaining element 10 is lowered somewhat. The crucible cleaning device 1 may comprise a control device 26, and the depth of a crucible is known beforehand and may be programmed into the crucible cleaning device 1. The crucible retaining element 10 thus stops when the cleaning head 3 is a predetermined distance from the inside of the bottom 28 of the crucible 2. This is known in the art of cleaning crucibles. The inside of the bottom 28 may be a generally flat area as in the illustrated embodiment, or it may be a curved area.

If the motor 8 is controlled by torque monitoring, the rotational speed of the cleaning head 3 can be adjusted to optimize the speed and provide as energyefficient performance as possible based on the feedback from the motor 8. The motor 8 may also cooperate with the vertical control devices 19, such that the speed of descent is also controlled. The control device 26 may connect and control the components of the crucible cleaning device 1. The speed of descent of the crucible retaining element 10 may be slow at first, and the pick up as the cleaning head 3 enters the crucible 2. The speed of descent may also be increased e.g. if the amount of residues inside the crucible 2 is low (e.g. the friction is low). As such, the crucible cleaning device 1 is very adaptable and a crucible 2 with less residues may be cleaned more energy efficient than a crucible 2 with more residues.

Similarly, the speed of descent may be decreased if the friction rises. The vertical control devices 19 may even be programmed to reverse the vertical movement, if needed. That is, if the friction between the cleaning head 3 and the crucible 2 e.g. rises above a predetermined threshold when the crucible retaining element 10 and crucible 2 is lowered, the vertical control devices 19 can be programmed to completely stop the descent, and even lift the crucible retaining element 10 and crucible 2 somewhat, to start the cleaning process again, or to allow e.g. a human operator to inspect the cleaning head 3. Factors such as the torque of the motor 8, the speed of the vertical control devices 19, etc. may easily be customized to different users, and different crucibles 2. The crucible cleaning device 1 may as such be operated very flexibly and energy efficient.

Because the crucible retaining element 10 of the crucible cleaning device 1 is controlled in a vertical direction, the weight of the crucible 2, fixed to the crucible retaining element 10, helps force the crucible 2 onto the cleaning head 3 as the crucible 2 is cleaned. Because of this design, utilizing the force of gravity, less energy is needed to clean the crucible 2. Due to less energy needed, the motors and control devices can all be electrically controlled, further making the crucible cleaning device 1 energy efficient and compact. Even if the vertical axis Z deviates from a truly vertical axis by some degrees, the same effect of utilizing gravity to lower the crucible onto the cleaning head 3 is attained. When the crucible retaining element 10 and the crucible 2 is raised from the cleaning head 3, a large amount of residue is cleaned from the crucible 2, and less energy is needed to elevate the crucible retaining element 10 and the cleaned crucible 2.

At the end of the cleaning cycle, the crucible retaining element 10 and crucible 2 may therefore be moved relatively fast up to the first position. The releasable locking means 17 are released, and the crucible 2 may be removed from the crucible cleaning device 1, cleaned and ready to be used. An indicator on the control device 26 may indicate that the cleaning cycle has finished, and that the crucible 2 is unlocked and can be removed from the crucible cleaning device 1.

Claims (15)

1. A crucible cleaning device (1), comprising:

a cleaning head (3) rotatably controlled about a vertical axis (Z) for cleaning residues from a crucible (2) comprising a brim (27) and a bottom (28);

a crucible retaining element (10) for mating with the crucible (2) and fixing the crucible (2) with the brim (27) positioned below the bottom (28) such that a centre axis (C) of the crucible (2) coincides with the vertical axis (Z);

the crucible retaining element (10) comprising releasable locking means (17) for fixing the crucible (2) to the crucible retaining element (10) and preventing rotation and movement of the crucible (2) in a horizontal plane (XY);

the crucible retaining element (10) is connected to at least one vertical control device (19) for controlling the crucible retaining element (10) and the crucible (2) along the vertical axis (Z) to lower the crucible (2) onto the cleaning head (3) and raising the crucible (2) from the cleaning head (3).

2. The crucible cleaning device (1) according to claim 1, wherein the cleaning head (3) is vertically connected to a motor (8) for controlling the rotation of the cleaning head (3).

3. The crucible cleaning device (1) according to claim 2, wherein the motor (8) is controlled by torque monitoring.

4. The crucible cleaning device (1) according to claims 2 or 3, wherein the crucible cleaning device (1) further comprises a debris collector (21) positioned below the cleaning head (3) and above the motor (8).

5. The crucible cleaning device (1) according to any one of the previous claims, wherein the crucible retaining element (10) comprises horizontal support elements (13) connected to vertical guide elements (14) for preventing movement in a horizontal plane (XY).

6. The crucible cleaning device (1) according to any one of the previous claims, where the crucible retaining element (10) comprises a flange (11) for mating with the brim (27) of the crucible (2).

7. The crucible cleaning device (1) according to any one of the previous claims, wherein the at least one vertical control device (19) is connected to the crucible retaining element (10) by a vertical translation element (20).

8. The crucible cleaning device (1) according to claim 7, wherein the at least one vertical control device (19) is a servo motor and the vertical translation element (20) is a trapezoid screw.

9. The crucible cleaning device (1) according to any one of the previous claims, wherein the cleaning head (3) comprises a plurality of replaceable fixed bits (5) provided on a base (4).

10. The crucible cleaning device (1) according to claim 9, wherein a plurality of the fixed bits (5) protrude from the base (4) in a radial direction from the vertical axis (Z), forming a gap between the base (4) and tips (6) of the fixed bits (5).

11. The crucible cleaning device (1) according to claims 9 or 10, wherein the base (4) comprises openings (7) for passing of residues from above the base (4) to below the base (4).

12. The crucible cleaning device (1) according to any one of the previous claims, wherein the releasable locking means (17) comprises a clamp controlled by an electric motor (18).

13. The crucible cleaning device (1) according to any one of the previous claims, wherein the crucible cleaning device (1) comprises vertically extending panels (24) to form a generally closed housing when the crucible (2) is mated with the crucible retaining element (10) to cover an upper part of the crucible cleaning device (1).

14. A method of cleaning residues from an inside of a crucible (2) with a crucible cleaning device (1) according to any one of the previous claims, comprising the steps of:

mating the crucible (2) on a crucible retaining element (10) of the crucible cleaning device (1);

fixing the crucible (2) to the crucible retaining element (10);

rotating a cleaning head (3);

lowering the crucible retaining element (10) and the crucible (2) along a vertical axis (Z) onto the cleaning head (3) until the crucible (2) is clean;

raising the crucible retaining element (10) and the crucible (2); releasing the crucible (2) from the crucible retaining element (10); removing the crucible (2) from the crucible cleaning device (1).

15. The method according to claim 14, wherein the speed of lowering the crucible retaining element (10) and the crucible (2) is controlled by the amount of torque on the motor (8).