Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A FURNACE FOR PREPARING FUSED (HOMOGENISED) SAMPLES
Document Type and Number:
WIPO Patent Application WO/2014/124484
Kind Code:
A1
Abstract:
The present disclosure provides a furnace for preparing fused (homogenised) samples. The furnace comprises a housing and a carousel positioned within the housing. The carousel is arranged to rotate about an axis and has a plurality of receiving stations. The receiving station is arranged such that crucibles with the samples and also casting dishes can be received by the carousel. The furnace also comprises a heater that is arranged to heat the samples to a temperature that is sufficient to melt the samples in the crucibles. Further, the furnace comprises at least one mechanism for loading and unloading the carousel with the crucibles; loading and unloading the carousel with the casting dishes; and decanting the melted samples from the crucibles into the casting dishes.

Inventors:
HOHENSTEIN, Boyne Friederich (7 Perina Way, City Beach, Western Australia 6015, AU)
Application Number:
AU2014/000107
Publication Date:
August 21, 2014
Filing Date:
February 11, 2014
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
IMP GROUP (PTY) LTD (34 Hasler Road, Osborne Park, Western Australia 6017, AU)
International Classes:
F27B9/16
Domestic Patent References:
WO2003098140A12003-11-27
Foreign References:
EP1455175A12004-09-08
EP2458388A22012-05-30
Other References:
See also references of EP 2956726A4
None
Attorney, Agent or Firm:
GRIFFITH HACK (Level 19, 109 St Georges TerracePerth, Western Australia 6000, AU)
Download PDF:
Claims:
Claims :

1. A furnace for preparing fused (homogenised) samples, the furnace comprising:

a housing;

a carousel positioned within the housing and arranged to rotate about an axis, the carousel having a plurality of receiving stations, the receiving station being

arranged such that crucibles with the samples and also casting dishes can be received by the carousel;

a heater arranged to heat the samples to a

temperature that is sufficient to melt the samples in the crucibles; and

at least one mechanism for:

loading and unloading the carousel with the crucibles ;

loading and unloading the carousel with the casting dishes; and

decanting the melted samples from the crucibles into the casting dishes.

2. The furnace of claim 1 wherein the at least one mechanism is arranged to move at least one crucible and at least one casting dish simultaneously.

3. A furnace for preparing fused (homogenised) samples and heating casting dishes, the furnace comprising:

a housing;

a carousel positioned within the housing and arranged to rotate about an axis, the carousel having a plurality of receiving stations, each receiving station being arranged such that crucibles with the samples and also casting dishes can be received by the carousel; a heater arranged for heating the samples to a temperature that is sufficient to melt the samples in the crucibles; and

at least one mechanism for:

loading and unloading the carousel with the crucibles ;

loading and unloading the carousel with the casting dishes;

wherein the at least one mechanism is arranged to load the carousel simultaneously with at least one crucible and at least one casting dish.

4. The furnace of claim 3 wherein the at least one mechanism is arranged for decanting melted samples from the crucibles into the casting dishes.

5. The furnace of any one of the preceding claims wherein the at least one mechanism comprises a respective component mechanism that is arranged to load the carousel simultaneously with the crucibles and the casting dishes and a respective component mechanism that is arranged to decant the melted samples form the crucibles into

respective casting dishes. 6. The furnace of any one of the preceding claims wherein the at least one mechanism is arranged such that one crucible and one respective casting dish are moved together . 7. The furnace of any one of the preceding claims wherein each receiving station of the carousel has at least one aperture for receiving at least crucible and at least one casting dish.

8. The furnace of claim 7 wherein the at least one aperture of each receiving station is arranged such that the at least one crucible and the casting dish are

positioned along a radius of the carousel when received by the at least one aperture.

9. The furnace of any one of claims 1 to 6 wherein the carousel comprises two or more component carousels that are positioned above one another and wherein the receiving stations of a first component carousel have apertures that are arranged for receiving the crucibles and the receiving stations of a second carousel have apertures arranged for receiving casting dishes.

10. The furnace of any one of claims 1 to 6 wherein the carousel comprises two or more component carousels that are positioned above one another and wherein the receiving stations of both a first and a second component carousel have apertures and wherein each aperture is arranged for receiving crucibles and casting dishes.

11. The furnace of any one of claims 1 to 6 wherein the carousel comprises two or more component carousels that are positioned above one another and wherein the receiving stations of both a first and a second component carousel have apertures and wherein each aperture is arranged to receive either a crucible or a casting dish in an

alternating manner.

12. The furnace of any one of any one of the preceding claims wherein the at least one mechanism comprises a component mechanism for decanting melted samples from the crucibles into the casting dishes and wherein that

component mechanism is positioned outside of the housing.

13. The furnace of any one of any one of the preceding claims wherein the at least one mechanism comprises a component mechanism for decanting melted samples from the crucibles into the casting dishes and wherein that

component mechanism is positioned inside of the housing. 14. The furnace of any one of the preceding claims wherein the housing has an access port in a side wall portion through which in use the crucibles and the casting dishes are moved in a substantially horizontal direction. 15. The furnace of any one of the preceding claims wherein the at least one mechanism comprises a first arm having a portion for supporting a crucible and a casting dish and being arranged for contraction and extension along a length of the arm whereby the first arm is arranged such that a crucible and a casting can be moved between a receiving station of the carousel and a position that is remote from the carousel, the first arm being arranged such that a crucible and a respective casting dish can be moved simultaneously between a receiving station of the carousel and a position that is remote from the carousel.

16. The furnace of claim 15 wherein the at least one mechanism comprises a second arm having a portion for supporting a crucible and a casting dish and being

arranged for contraction and extension along a length of the arm whereby the second arm is arranged such that a crucible and a casting can be moved between a receiving station of the carousel and a position that is remote from the carousel, the second arm being arranged such that a crucible and a respective casting dish can be moved between a receiving station of the carousel and a position that is remote from the carousel. 17. The furnace of claim 16 wherein the first arm is arranged for positioning the crucibles and the casting dishes into the receiving stations of the carousel and the second arm is arranged for removing the crucibles and the casting dishes from the receiving stations. 18. The furnace of any one of the preceding claims comprising a control system that is arranged to control operation of the furnace in an automated manner.

19. The furnace of claim 18 wherein the control system is configured to effect removal of a crucible and a

respective casting dish after the sample has been treated in a manner such that the sample forms a homogeneous glass when cooled subsequent to the heat treatment. 20. The furnace of any one of the preceding claims wherein the furnace is arranged to impart a rocking, oscillating or vibrating motion to the samples in the crucibles when the crucibles are positioned in the

receiving stations and exposed to heat treatment.

21. The furnace of any one of the preceding claims wherein the furnace comprises an arrangement for lifting and lowering the crucibles and/or casting dishes relative to the at least one mechanism.

22. The furnace of any one of the preceding claims wherein the heater is arranged for heating both the crucibles with the samples and the casting dishes.

23. A furnace system for preparing fused (homogenised) samples, the furnace system comprising:

a first furnace for preheating of the samples; and a second furnace for receiving crucibles with samples after preheating of the samples, the second furnace being in accordance with any one of claims 1 to 22.

24. A method of preparing fused (homogenised) samples, the method comprising the steps of: providing crucibles with samples and casting dishes to at least one mechanism for moving the crucibles and the casting dishes; moving groups of at least crucible and at least one casting dish in sequence to receiving stations of a carousel of the furnace using the at least one mechanism for moving the crucibles and casting dishes; exposing the crucibles with the samples and the casting dishes to heat treatment in the furnace sufficient for melting of the samples; rotating the crucibles and casting dishes about an axis of the carousel; and subsequently removing the groups of the crucibles and the casting dishes in sequence using the at least one mechanism for moving the crucibles and the casting dishes and

positioning the crucibles and the casting dishes on a conveyor for moving the crucibles away from the furnace.

25. The method of claim 24 comprising decanting the melted samples from the crucibles into respective casting dishes .

26. The method of claim 25 comprising decanting the melted samples from the crucibles into respective casting dishes at a position inside the furnace.

27. The method of claim 25 comprising decanting the melted samples from the crucibles into respective casting dishes at a position outside the furnace. 28. The method of any one of claims claim 24 to 27 wherein the furnace is a second furnace and the step of providing crucibles with samples and casting dishes comprises the initial step of exposing the samples in the crucibles to a preheating treatment in a first furnace. 29. The method of any one of claims 24 to 28 wherein the step of moving the crucibles and the casting dishes comprises moving the crucibles and casting dishes in a substantially horizontal direction and through an access port in a side wall of a housing of the furnace. 30. The method of any one of claims 24 to 29 wherein the method is conducted in an automated manner.

Description:
A FURNACE FOR PREPARING FUSED (HOMOGENISED ) SAMPLES

Field of the Invention

The present invention broadly relates to a furnace for preparing fused (homogenised) samples.

Background of the Invention

A variety of samples such as mineral samples, cement samples and other materials need to be homogenized (or "fused") before they can be analysed by analytical

techniques such as X-Ray fluorescence (XRF) spectrometric analysis, inductively-coupled plasma mass spectrometry (ICP MS) and other analytical techniques. Sample

preparation typically involves mixing the sample with a flux and positioning the resultant mixture into a furnace that is heated to form a homogeneous melt.

In the case of XRF analysis the homogeneous melt is then allowed to cool in a crucible to form a glass bead which is then analysed or the homogenized melt is cast into a casting dish that is usually preheated and allowed to cool prior to the analysis. PCT publication number WO2003098140 discloses a furnace that has a carousel for movement of the batch of samples about an axis.

The present invention provides further improvement. Summary of the Invention

The present invention provides in a first aspect a furnace for preparing fused (homogenised) samples, the furnace comprising:

a housing;

a carousel positioned within the housing and arranged to rotate about an axis, the carousel having a plurality of receiving stations, the receiving station being

arranged such that crucibles with the samples and also casting dishes can be received by the carousel;

a heater arranged to heat the samples to a

temperature that is sufficient to melt the samples in the crucibles; and

at least one mechanism for:

loading and unloading the carousel with the crucibles ;

loading and unloading the carousel with the casting dishes; and

decanting the melted samples from the crucibles into the casting dishes.

The at least one mechanism may be arranged such that the crucibles and the casting dishes are moved separately, but typically is arranged to move at least one crucible and at least one casting dish simultaneously.

The present invention provides in a second aspect a furnace for preparing fused (homogenised) samples and heating casting dishes, the furnace comprising:

a housing;

a carousel positioned within the housing and arranged to rotate about an axis, the carousel having a plurality of receiving stations, each receiving station being arranged such that crucibles with the samples and also casting dishes can be received by the carousel;

a heater arranged for heating the samples to a temperature that is sufficient to melt the samples in the crucibles; and

at least one mechanism for:

loading and unloading the carousel with the crucibles; and

loading and unloading the carousel with the casting dishes;

wherein the at least one mechanism is arranged to load the carousel simultaneously with at least one

crucible and at least one casting dish.

The at least one mechanism of the furnace in accordance with the second aspect of the present invention may arranged for decanting melted samples from the crucibles into the casting dishes.

The following introduces features that the furnace in accordance with the first aspect or in accordance with the second aspect of the present invention may have. The heater may be arranged for heating both the crucibles with the samples and the casting dishes.

The at least one mechanism may be arranged such that one crucible and one respective casting dish are moved

together . The at least one mechanism for moving may be arranged for manual operation, but typically is arranged for automatic operation controlled by a controlling system. The at least one mechanism may comprise a respective component mechanism that is arranged to load the carousel simultaneously with the crucibles and the casting dishes and a respective component mechanism that is arranged to decant the melted samples form the crucibles into

respective casting dishes.

Each receiving station of the carousel may have at least one aperture for receiving at least crucible and at least one casting dish.

In one specific embodiment each receiving station

comprises one aperture for receiving one crucible and one casting dish. The aperture of the receiving station may be arranged such that the crucible and the casting dish are positioned along a radius of the carousel when received by the aperture. The aperture may comprise a first portion for receiving one of the casting dish and the crucible and a second portion for receiving the other one of the crucible and the casting dish. The first and second portions may be positioned along a radius of the carousel.

The carousel may also comprise two or more component carousels that are positioned above one another. The receiving stations of a first component carousel may have apertures that are arranged for receiving the crucibles and the receiving stations of a second carousel may be have apertures arranged for receiving respective casting dishes. Alternatively, the receiving stations of both the first and the second component carousel may have apertures that are arranged for receiving crucibles and casting dishes for example in an alternating manner. The component mechanism for decanting may be positioned inside the housing of the furnace or outside of the housing .

The heater may be arranged to heat the crucibles with the respective sample mixtures, such as a suitable mixture of a mineral sample material and a flux, and the casting dishes to a temperature to effect melting of each sample and flux mixtures. In one embodiment the at least one mechanism is arranged to move the crucibles and the casting dishes in a radial direction of the carousel. The housing typically has an access port in a side wall portion through which in use the crucibles and the casting dishes are moved in a substantially horizontal direction. The access port may comprise an access door that is arranged to close the access port.

The at least one mechanism may comprise a first arm having a portion for supporting a crucible and/or a casting dish and being arranged for contraction and extension along a length of the arm whereby the first arm is arranged such that a crucible and/or a casting can be moved between a receiving station of the carousel and a position that is remote from the carousel. In one specific embodiment of the present invention the first arm is arranged such that a crucible and a respective casting dish can be moved simultaneously between a receiving station of the carousel and a position that is remote from the carousel. The at least one mechanism may comprise a second arm having a portion for supporting a crucible and/or a casting dish and being arranged for contraction and extension along a length of the arm whereby the second arm is arranged such that a crucible and/or a casting can be moved between a receiving station of the carousel and a position that is remote from the carousel. In the specific embodiment of the present invention the second arm is arranged such that a crucible and a respective casting dish can be moved between a receiving station of the carousel and a position that is remote from the carousel.

The first arm may be arranged for positioning the

crucibles and the casting dishes into the receiving stations of the carousel and the second arm may be

arranged for removing the crucibles and the casting dishes from the receiving stations.

The furnace may also comprise a device for measuring temperature .

The furnace may comprise a control system that is arranged to control operation of the heater, the carousel and the at least one mechanism. The control system may be

configured to effect removal of a crucible and typically also a respective casting dish after the sample has been treated in a manner such that the sample forms a

homogeneous glass when cooled subsequent to the heat treatment .

The control system may be arranged to control operation of the furnace in an automated manner.

The control system may comprise a microprocessor and may be arranged to control operation of the furnace such that the first arm in use positions a sequence of crucibles and casting dishes into a sequence of receiving stations and the heater subsequently heats the samples in the crucibles and the casting dishes. Further, the control system may be arranged to control the furnace such that the second arm removes the crucibles and the casting dishes sequentially from the receiving stations after completion of a

predetermined heat treatment. The control system may be arranged such that loading, rotation by the carousel, heat treatment, unloading and decanting are performed in an automated manner. Further, the control system may be arranged such that parameters are selectable by a user. For example, the parameters may include a rotation rate of the carousel, a temperature of the furnace or a duration of the heat treatment.

The control system in accordance with one example

comprises a timer for timing a period of time during which the samples are exposed to the heat treatment. The control system with the timer may be arranged to interrupt the heat treatment after a predetermined time or effect an alarm signal. The control system may comprise a memory device for storing control parameters.

The furnace may be arranged to impart a rocking,

oscillating or vibrating motion to the samples in the crucibles when the crucibles are positioned in the

receiving stations and exposed to heat treatment and which may be controlled by the control system.

The furnace may comprise an arrangement for lifting and lowering the crucibles and/or casting dishes relative to the at least one mechanism. In this case, the control system may be arranged such that the first arm delivers a crucible and typically also a respective casting dish to a position over a respective receiving station and the arrangement for lowering and lifting lifts the carousel such that the crucible typically also the respective casting dish is positioned in the aperture of the

respective receiving station.

The control system may be arranged such that, after completion of heat treatment, the arrangement for lowering and lifting the crucibles and/or casting dishes lowers the carousel to a position below a crucible and/or a casting dish on the second arm and the second arm then moves the crucible and/or the casting dish to a position outside the housing of the furnace.

Further, the furnace may comprise a conveying system that is arranged for conveying a sequence of crucibles and casting dishes to the first arm and a sequence of

crucibles and casting dishes away from the second arm of the at least one mechanism. The furnace may be arranged such that the conveying system moves the crucibles and the casting dishes to a remote location after decanting the melted sample mixture from the crucibles into the casting dishes .

In one embodiment the carousel is one of a plurality of carousels. For example a first carousel may be positioned over a second carousel and arranged for rotation about the same axis.

The access door of the access port may be arranged for remote controlled operation and the control system

typically is arranged to control the operation of the access door in an automated manner to allow operation of the at least one mechanism. The control system may be arranged to control the operation of the access door in a manner such that loss of thermal energy through the access port is reduced or minimised.

The present invention provides in a third aspect a furnace system for preparing fused (homogenised) samples, the furnace system comprising:

a first furnace for preheating of the samples; and a second furnace for receiving crucibles with samples after preheating of the samples, the second furnace being in accordance with the first aspect of the present

invention.

The present invention provides in a fourth aspect a method of preparing fused (homogenised) samples, the method comprising the steps of: providing crucibles with samples and casting dishes to a at least one mechanism for moving the crucibles and the casting dishes; moving groups of at least crucible and at least one casting dish in sequence to receiving stations of a carousel of the furnace using the at least one mechanism for moving the crucibles and casting dishes; exposing the crucibles with the samples and the casting dishes to heat treatment in the furnace sufficient for melting of the samples; rotating the crucibles and casting dishes about an axis of the carousel; and subsequently removing the groups of the crucibles and the casting dishes in sequence using the at least one mechanism for moving the crucibles and the casting dishes and positioning the crucibles and the casting dishes on a conveyor for moving the crucibles away from the furnace.

The method may also comprise decanting the melted samples (typically with a flux) from the crucibles into respective casting dishes at a position outside of the furnace or at a position inside the furnace.

Further, the furnace may be a second furnace and the step of providing crucibles with samples and casting dishes may comprise the initial step of exposing the samples in the crucibles to a preheating treatment in a first furnace.

The step of moving the crucibles and the casting dishes may comprise moving the crucibles and casting dishes in a substantially horizontal direction and typically through an access port in a side wall of a housing of the furnace. The method may be conducted in an automated

manner. Further, the method may comprise selecting parameters, such as a temperature of the furnace or a rotation rate of the carousel.

The method may also comprise imparting a rocking or oscillating motion to the samples in the crucibles during heat treatment.

The invention will be more fully understood from the following description of specific embodiments of the invention. The description is provided with reference to the accompanying drawings. Brief Description of the Drawings

Figures 1 shows a top view of a furnace for preparing fused (homogenised) samples and heating casting dishes in accordance with an embodiment of the present invention;

Figures 2 and 3 show schematic cross-sectional side views of the furnace; Figures 4 and 5 show top views of the furnace;

Figures 6 to 8 show schematic cross-sectional side views of the furnace; Figures 9 and 10 show schematic perspective views of the furnace; and

Figure 11 is s flow chart illustrating a method of preparing fused (homogenised) samples and heating casting dishes in accordance with an embodiment of the present invention .

Detailed Description of Specific Embodiments Embodiments of the present invention relate to a furnace for preparation of fused (homogenized) samples suitable for analytical techniques, such as X-ray fluorescent spectrometry or mechanical analysis techniques such as inductively-coupled plasma mass spectrometry.

Referring now to Figures 1 to 10, a furnace for, and a method of, preparing fused (homogenised) samples and heating casting dishes in accordance with embodiments of the present invention is now described.

Sample preparation typically involves mixing the sample with a flux and weighing the resultant sample mixture. The sample with flux is then placed in a furnace 100 in which the sample mixture that is heated to form a homogeneous melt . The furnace 100 comprises a housing 102 in which a

carousel 104 is positioned. The carousel 104 is arranged for rotation about an axis and Figures 2 and 6 to 8 show a drive 105 of the carousel 104. The carousel 104 has a plurality of receiving stations 106 that each have an aperture and the apertures are positioned in a ring-like manner along the periphery of the carousel 104. Each aperture of a receiving station 106 is sized to receive and hold a crucible 108 and a respective casting dish 109. The crucibles 108 and the respective casting dishes 109 have radial lips that extend in a ring-like manner at an upper portion of the crucibles 108 and the casting dishes 109, which rest on the carousel 104 when the crucibles 108 and the casting dishes 109 are positioned in the receiving stations 106.

The furnace 100 is arranged for heating samples in the crucibles 108 and the casting dishes 109 to a temperature suitable for melting the samples to generate fused

(homogenised) samples that form a homogeneous glass bead when cooled and are suitable for the above-mentioned analysis techniques. The samples for fusion may for example include mined materials (in powder form) or any other type of mineral that is suitably prepared. The furnace 100 also comprises a mechanism 110 for moving the crucibles 108 and the casting dishes 109 between respective receiving stations 106 and a location that is exterior to the housing 102. The mechanism 110 comprises a first arm 112 and a second arm 114. The first arm 112 is arranged for moving the crucibles 108 and the casting dishes 109 from the exterior position to a receiving station 106 of the carousel 104. The second arm 114 is arranged for moving the crucibles 108 and the casting dishes 109 out of receiving stations 106 and to the exterior location. Both arms 112 and 114 have suitable support surfaces for supporting the crucibles 108 and the casting dishes 109 and are arranged for moving by suitable electrical or hydraulic means in horizontal directions.

Each aperture of each receiving station 106 has a first portion 106a and a second portion 106b. Each first portion 106a and each respective second portion portions 106b is positioned along a radius of the carousel 104. The first portions 106a have a diameter that is smaller than that of the second portions 106b. In the illustrated embodiment the crucibles 108 have an outer diameter (below the described lip) that is smaller than that of the casting dishes 109 and the first and second portions 106a and 106b have corresponding inner diameters. However, a person skilled in the art will appreciate that various other arrangements are possible. Figure 1 shows crucibles 108 and respective casting dishes 109 positioned on the first arm 112 and the second arm Figure 2 shows the first arm 112 after it moved a crucible 108 and a respective casting dish 109 over a receiving station 106 of the carousel 104 to load the carousel. The carousel 104 comprises a mechanism for lifting the carousel 104 along an axis of the carousel 104. Figures 3 and 4 shows the carousel 104 after it has been lifted to receive crucible 108 and a casting dish 109 in respective aperture portions 106a and 106b of the receiving station 106.

Figures 5 and 6 show the first arm 112 in a retracted configuration after leaving the carousel 104 and the second arm 114 in an extended configuration with end portions of the first arm 114 being positioned at another one of the crucibles 108 and another one of the casting dishes 109 after completion of the heat treatment for the respective sample. The carousel 104 is then lowered such that the crucible 108 and the casting dish 109 is

positioned on a support surface of the second arm 114 and the second arm 114 is subsequently contracted, which is illustrated in Figure 7.

The furnace 100 also comprises a mechanism 115 for

decanting the sample from the crucibles 108 into

respective casting dishes 109. The mechanism 115 for decanting the samples is arranged to grip a crucible 108 and rotate the crucible 108 by 180 ° about a horizontal axis such that the respective sample is decanted into an adjacent casting dish 109. In the embodiment as

illustrated in Figures 1 to 10, the mechanism for

decanting 115 forms a part of the mechanism 110 for moving the crucibles 108 and the casting dishes 109 and is operated by suitable electrical or hydraulic means. In the illustrated embodiment the mechanism 110 for moving the crucibles 108 and the casting dishes 109 comprises two of the mechanisms 115 for decanting for decanting and one of the mechanisms 115 is positioned at each arm 112 and 114. A person skilled in the art will appreciate that in an alternative variation only the second arm 114 may comprise the mechanism for decanting 115. The mechanism for decanting 115 is arranged for decanting of the sample at a position outside the housing 102.

However, a person skilled in the art will appreciate that the in a variation of the described embodiment the

mechanism 115 for decanting the sample may also be

positioned and arranged for decanting the sample at a position within the housing 102.

Figures 8 and 9 show the mechanism 115 for decanting during decanting of a sample from a crucible 108 into a respective casting dish 109. Figure 10 shows the mechanism 115 for decanting after decanting has been completed and before the crucible 108 and the casting dish 109 are conveyed by a suitable conveying system to a location that is remote from the furnace 100.

After decanting the samples in the casting dishes 109 (which are formed from platinum) , the samples are allowed to cool such that a glass bead is formed, which

subsequently is analysed using X-ray fluorescence (XRF) techniques or other suitable techniques. The glass beads are removed from the casting dishes 109, which are cleaned for reuse. A person skilled in the art will appreciate that such a conveying system may take any suitable form and such systems are known in the art. The housing 102 of the furnace 100 has an access port 116 at a side portion through which the arms 112 and 114 move the crucibles 108 and the casting dishes 109. The access port 116 has an access door (not shown) that can be remotely opened and closed when the first or second arms 112, 114 are in use. In variations of the described embodiment the furnace 100 may also comprise more than one carousel 104 and the carousels may be positioned over one another and arranged for rotation about a common axis driven by the drive 105. In this case the furnace 100 comprises a suitable means for moving all carousels up and down such that the arms 112 and 114 are able to operate as described above. Alternatively, the furnace 100 may also comprise more than one mechanism for moving the crucibles 108 and casting dishes 109 and the mechanisms may be stacked on top of one another in the same manner as the carousels .

The furnace 100 comprises control electronics (not shown) that is arranged to allow automated operation of the furnace 100. Further, the furnace 100 comprises

temperature sensors (not shown) and is arranged such that a user can select a temperature and a duration of the heat treatment. These parameters may be preselected and the control electronics is arranged to operate in accordance with the pre-selected parameters in an automated manner. Consequently, the control electronics controls operation of the drive 105, a heater (not shown), the carousel 104, the first and second arms 112 and 114, and the mechanism 115 for decanting the samples from the crucibles 108 into the respective casting dishes 109. The control electronics is also arranged to control operation of the access door (not shown) at the access port 116 when the first or second arms 112, 114 are in use. In one specific

embodiment a drive shaft of the carousel 104 is arranged for imparting an oscillating movement about the axis of the carousel 104 and is also controlled by the control system.

In another variation of the described embodiment a further furnace (not shown) may be used for pre-heating (or "pre- roasting", typically at a temperature of the order of 500 ° C) of the samples to initiate chemical processes prior to forming the fused (homogenized) samples using the furnace 100 at a temperature that may be of the order of 1000 ° C.

Referring now to Figure 11, a flow chart of a method 1100 of preparing fused (homogenised) samples and heating casting dishes in accordance with an embodiment of the present invention is now described. The furnace may be the above-described furnace 100. The method 1100

comprises the initial step 1102 of providing crucibles with samples and casting dishes to a mechanism for moving the crucibles and the casting dishes. Further, the method 1100 comprises step 1104 of moving groups of the crucibles and the casting dishes in sequence to respective receiving stations of a carousel of the furnace using the mechanism for moving the crucibles and casting dishes. Further, the method 1100 comprises step 1106 of exposing the crucibles and the casting dishes to heat treatment in the furnace sufficient for melting of the samples. Step 1108 rotates the crucibles and casting dishes about an axis of the carousel and step 1110 removes the groups of crucibles and the casting dishes in sequence using the mechanism for moving the crucibles and the casting dishes. Step 1112 decants the samples from the crucibles into the respective casting dishes (at positions inside or outside of the furnace) and step 1114 positions the crucibles and the casting dishes on a conveyor for moving the crucibles away from the furnace.

Having described a specific embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various changes and

modifications could be effected therein by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims. For example, in a variation of the described embodiment the carousel may also comprise two or more component carousels that are positioned above one another. The receiving stations of a first component carousel may have apertures that are arranged for receiving the crucibles 108 and the receiving stations of a second carousel may have apertures arranged for receiving the casting dishes 109. Alternatively, each component carousel may be arranged such that the crucibles and the casting dishes are placeable in each carousel component in an alternating manner.