DEVICE AND METHOD FOR THERMAL ANALYSIS OF A SAMPLE

Description

[0001] The present invention relates to a device and a method for a thermal analysis of a sample.

[0002] Devices for the thermal analysis of a sample are known in various designs from the prior art and comprise a sample chamber for holding (at least) one sample to be analyzed or for holding (at least) one sample crucible containing the sample to be analyzed. Furthermore, the devices include a temperature control unit for maintaining the temperature of the sample chamber and a measuring unit for measuring the temperature of the sample and one or more other measured parameters.

[0003] Thermal analysis methods can be advantageously used, for example, to characterize material properties (e.g., specific heat capacity, thermal conductivity, melting, decomposition and crystallization temperatures), including, for example, the properties of temperature-dependent or temperature-changing processes (e.g., enthalpies during phase transitions or chemical reactions, etc.).

[0004] Examples of methods for thermal analysis include thermogravimetry (TG), differential thermal analysis (DTA), and the derived method of differential scanning calorimetry (DSC).

[0005] In the methods of particular interest within the scope of the invention, the sample is typically tempered according to a temperature program, during which a chamber temperature inside the sample chamber is changed and simultaneously the sample temperature and additionally one or more further measured parameters relating to the properties of the sample are measured by means of the measuring device.

[0006] In thermogravimetry (TG), one such "property of the sample" is, for example, the weight or mass of the sample measured during a temperature program.

[0007] Depending on the specific design of the measuring device, in thermal analysis, in addition to measuring the sample temperature and, for example, the sample mass, a large number of other physical quantities can, in principle, be measured during the course of the temperature program.

[0008] An example of this is the determination of the temperature-dependent caloric effects of a sample using DSC with simultaneous determination of the temperature-dependent mass of the sample using thermogravimetry (TG). Another example is the determination of the type and quantity of volatile decomposition products of a sample during the course of a temperature program using mass spectrometry (MS) with simultaneous determination of the temperature-dependent mass of the sample using thermogravimetry (TG). Thermal analysis using several different methods simultaneously is also referred to here as "simultaneous thermal analysis."

[0009] The term used here, namely the "properties of the sample" (measured by the measuring device), is therefore to be understood very broadly and can, for example, include the aforementioned "type and quantity" of volatile decomposition products.

[0010] With certain materials and samples made from them, the problem arises that the samples can be contaminated by components of the atmosphere such as oxygen, carbon dioxide, water (humidity), etc., and / or can react chemically with such components, so that the samples in question are thereby altered in an undefined way.

[0011] With regard to the storage and / or transport of a sample, a simple solution to the problem is to "package" the sample immediately after its preparation in a sample crucible with an airtight crucible cover placed on top, or to prepare the sample in a sample crucible and immediately provide this crucible with the airtight crucible cover.

[0012] However, even with a sample contained in a crucible with an airtight crucible cover placed on top, the aforementioned risk of contamination and / or chemical reaction remains as soon as the sample is introduced into the device as part of a so-called "sample preparation" and the crucible cover has to be removed or otherwise opened in preparation for thermal analysis, which is mandatory for many thermal analyses.

[0013] One possible solution to this problem is to place the still airtight sealed sample crucible together with the device into an airtight sealed chamber (so-called "glove box") and then carry out the sample preparation and thermal analysis in this chamber under vacuum or under a protective gas atmosphere.

[0014] Apart from this very elaborate and, for cost reasons, rather impractical solution, the problem can be somewhat mitigated by using a sample crucible with a crucible cover which does not have to be completely removed (e.g., unscrewed) during sample preparation, but in which, for example, a small hole can be pierced with a needle to create a medium-permeable connection between the inside of the sample crucible and the sample chamber of the device for the subsequent thermal analysis.

[0015] However, even with this procedure, i.e., "puncturing" the crucible cover in ambient air, there remains a certain risk of contamination and / or chemical reaction with components of the ambient air during the introduction of the sample into the device.

[0016] German patent DE 198 36 372 A1 describes a heating unit for vaporizing a sample by heating. The sample is located in a container whose opening is hermetically sealed by a rubber gasket. The heating unit comprises hollow needle-shaped inlet tubes for supplying carrier gas into the container and a hollow needle-shaped outlet tube for expelling the vaporized components and the carrier gas from the container. These outlet tubes pierce the rubber gasket when the container is inserted into the heating unit.

[0017] JP 2013-186090 A describes a calorimeter with two receiving sections formed in a heating area for receiving individual sample containers. The openings of the receiving sections are each closed with a stopper, and the sample containers are each closed with a screw cap, with a hollow needle passing through the stopper and the screw cap, allowing gases from the respective sample container to be released via the needle.

[0018] It is an object of the present invention to reduce, in a device and a method for thermal analysis, the risk of alteration of the sample due to undesired chemical or physical reactions during sample preparation.

[0019] According to a first aspect of the invention, this problem is solved by a device for a thermal analysis of a sample having the features of claim 1.

[0020] The invention advantageously makes it possible to drastically reduce the risk of undesirable changes to the sample as a result of chemical or physical reactions with components of the ambient air, since the sample crucible can be introduced into the sample chamber in an airtight sealed state and opened there under a defined gas atmosphere.

[0021] In a preferred embodiment of the invention, the gas atmosphere generated in the sample chamber contains at least one gas selected from the group consisting of nitrogen, argon, and helium. Such a gas atmosphere can also be referred to as an inert gas atmosphere or a protective gas atmosphere, depending on its purpose.

[0022] Many conventional devices and methods for thermal analysis already provide for the sample chamber to be permeated by a so-called carrier gas during the thermal analysis process in order to remove gaseous substances released from the sample (e.g., volatile components or volatile reaction products) in a defined manner and supply them to an analysis unit of the measuring device, such as a gas chromatography / mass spectrometry system.

[0023] In this case, it may be provided that at least part (e.g., gas source, gas inlet, etc.) of the means for generating a carrier gas flow in the sample chamber is also used to generate the gas atmosphere in the sample chamber during sample preparation. The compositions of the gases used during sample preparation ("protective gas") and during thermal analysis ("carrier gas") can be identical or different.

[0024] In one embodiment of the invention, the chamber cover and the piercing device are structurally combined as a single cover / piercing unit.

[0025] This offers the advantage for many existing device designs that the invention can be implemented simply and cost-effectively through a minor modification of the design.

[0026] In a further development of this embodiment, it is provided that the device has an additional chamber cover which can be placed on the chamber opening of the sample chamber instead of the cover / piercing unit.

[0027] This further development is particularly advantageous, for example, when the chamber cover, in addition to its function of preventing the exchange of media and / or energy (heat) between the sample chamber and the environment, has at least one further function during thermal analysis. According to this development, after the hole has been pierced in the crucible cover and before the thermal analysis of the sample, the cover / piercing unit can be replaced by a chamber cover optimized with respect to the aforementioned additional function(s). Such an additional function could, for example, be to provide a gas outlet through which the gas acting as a carrier gas during the thermal analysis of the sample, along with gaseous components originating from the sample, is routed from the sample chamber to an analysis unit of the measuring device (e.g., gas chromatography / mass spectrometry system).

[0028] In another further development of this embodiment, it is provided that the cover / piercing unit has a gas outlet (e.g. at least one small opening) through which gas from the gas atmosphere of the sample chamber can flow out into the environment when the cover / piercing unit is placed on the chamber opening.

[0029] With this further development, a rapid and complete displacement of air from the sample chamber can be advantageously achieved immediately after the covering / piercing unit is attached, by generating the gas atmosphere through a gas flow through the sample chamber caused by the gas guidance device, in which gas flows into the sample chamber, e.g. at a point relatively far from the chamber opening, and is allowed to flow out at the aforementioned gas outlet of the covering / piercing unit.

[0030] If, at this stage of sample preparation (and preferably with gas still flowing), the hole is then pierced in the crucible cover and subsequently the cover / piercing unit is removed from the chamber opening of the sample chamber (in order to replace it with another chamber cover before carrying out the thermal analysis), the gas flow through the sample chamber in this direction, i.e. from the inside of the device to the chamber opening of the sample chamber, advantageously prevents or minimizes the ingress of ambient air into the sample chamber.

[0031] The cover / piercing unit can, for example, have a wall provided for covering the chamber opening and a guide bearing formed on the wall for movable support of the needle, wherein the needle can extend from an inner side of the wall facing the sample chamber when the cover / piercing unit is attached, through the wall to an outer side of the wall facing away from the sample chamber when the cover / piercing unit is attached.

[0032] In the latter case, for example, it can be provided that a "needle drive" intended for the piercing process is achieved by a mechanical action (thrust) on the section of the needle located on the outside of the wall. This has the advantage, for example, that no corresponding drive components are required inside the sample chamber for driving the needle. Rather, these drive components can be arranged on the outside of the cover / piercing unit without affecting the sample chamber and without causing space constraints.

[0033] If, in the application situation of the device, a vertical piercing movement of the needle from top to bottom is provided, then in many cases, a manually operated and therefore very simple embodiment of a cover / pierce unit may be of particular interest, which has a wall provided for covering the chamber opening and a guide bearing formed on the wall for the movable support of the needle, wherein the needle extends from the aforementioned inner side of the wall through the wall to the aforementioned outer side of the wall, and wherein the cover / pierce unit further comprises a weight guided vertically on the cover / pierce unit, which can be dropped by a user from a predetermined height relative to the needle onto a distal end of the needle or another point on the needle.

[0034] As an alternative to a manual operation by which such a weight can be lifted to the predetermined height and then dropped, it is also possible to equip the piercing device or the cover / piercing unit with a suitable motorized device.

[0035] As an alternative to using a falling weight, which generally produces an advantageous, relatively rapid insertion motion of the needle, it is also possible to provide a motorized device that acts on the needle via a gear connection to drive its insertion motion. With such an embodiment, it is particularly possible to provide a relatively slow insertion motion of the needle.

[0036] An optimal piercing motion (e.g., rapid or slow, with a short or long stroke), as well as, for example, an optimal shape design of a needle piercing the crucible cover, and in particular of its tip, can be determined empirically depending on the application (construction of the crucible cover).

[0037] In one embodiment, the needle has a rotationally symmetrical shape at least in the region of its tip and an adjacent shaft region (e.g., a cylindrical shaft with a conical tip). With a conical needle tip, an angle defined by the needle tip when viewed from the side can, for example, lie in a range of 5° to 60°, and in particular 10° to 30°.

[0038] In one embodiment of the invention, the piercing device has a mechanical stop to limit the piercing depth of the needle. Alternatively or additionally, the piercing device may, for example, have a spring mechanism that preloads the needle against its piercing direction, whereby, for example, in the aforementioned embodiment with a falling weight, a defined piercing depth can also be achieved.

[0039] In one embodiment of the invention, the piercing device includes a mechanical centering device for centering the sample pot including the pot cover with respect to the needle.

[0040] The centering device can, for example, have two or more centering jaws for contacting a lateral surface of the sample pot or the pot cover placed on it, in order to force the sample pot together with the pot cover into a specific position relative to the needle (centering) before the hole is pierced in the pot cover of the sample pot by means of the needle of the piercing device.

[0041] In one embodiment of the invention, it is provided that a crucible holder with a support surface for placing the sample crucible is formed in the sample chamber, wherein the crucible holder is movable between a first position for placing the sample crucible and piercing a hole in the crucible cover and a second position for carrying out the thermal analysis of the sample.

[0042] The second position of the movable crucible holder is preferably provided further away from the chamber opening and / or "further inside the device" than the first position.

[0043] In a more specific embodiment, the crucible holder is movable in the vertical direction, with the second position being located further away from the chamber opening and / or "further inside the device" than the first position.

[0044] Although movable crucible holders are often provided in devices known from the prior art, they primarily serve to simplify the insertion and placement of the sample crucible, held, for example, with tweezers, into the device (e.g., through a relatively small chamber opening of the sample chamber). It should be borne in mind that, in order to ensure the most precise temperature control of the sample to be analyzed in the sample chamber, the sample must generally be in a position "further inside" the device during the subsequent analysis.

[0045] Within the scope of the present invention, the aforementioned movable crucible holder offers, for example, the additional advantage that the constructive realization of the piercing device, whether structurally combined with the chamber cover (as a cover / piercing unit) or separate from the chamber cover, becomes simpler.

[0046] Furthermore, the aforementioned movable crucible holder makes it possible (with appropriate design) to keep away mechanical stresses caused by piercing the hole in the crucible cover of the sample crucible from mechanically sensitive components of the device, for example a balance intended for thermogravimetric analysis (TG).

[0047] A further advantage of the embodiment with a movable crucible holder arises if the device has an additional chamber cover that can be placed on the chamber opening of the sample chamber instead of a cover / piercing unit. In this case, it can be provided that the sample crucible, along with the already pierced crucible cover, is moved from the first position (for placing the sample crucible and piercing the crucible cover) to a second position that is "further inwards" (e.g., recessed downwards into the device) or at least further away from the chamber opening compared to the first position, before the cover / piercing unit is then removed from the chamber opening of the sample chamber (in the second position of the crucible holder) and replaced by the other chamber cover.

[0048] Since the sample crucible is located further inside or at least further away from the chamber opening in the second position, where a certain exchange between the gas atmosphere and ambient air can take place after the cover / piercing unit has been removed, the sample is particularly well protected from contact with ambient air during this phase (replacement of the chamber cover).

[0049] In this context, it should also be noted again that the previously mentioned inert gas flow through the sample chamber from the interior of the device towards the chamber opening already advantageously protects the sample from contact with ambient air. This protection can, however, be further enhanced by moving the sample crucible (with the already pierced crucible cover) from the first position to the second position, thus moving it further away from the chamber opening.

[0050] According to another aspect of the invention, the problem stated at the outset is solved by a method for a thermal analysis of a sample with the features of claim 8.

[0051] The embodiments and special configurations described here for the device according to the invention can, individually or in any combination, also be provided in an analogous manner as embodiments or special configurations of the method according to the invention, and vice versa.

[0052] In one embodiment, the chamber cover and the piercing device are structurally combined as a cover / piercing unit, wherein, after piercing the hole in the crucible cover and before carrying out the thermal analysis of the sample, the cover / piercing unit is removed from the chamber opening of the sample chamber and replaced by another chamber cover.

[0053] In a further development of this embodiment, it is provided that the generation of the defined gas atmosphere is realized by a gas flow through the sample chamber effected by means of the gas guidance device, the flow rate of which is higher during the replacement of the cover / piercing unit by the other chamber cover than during the performance of the thermal analysis.

[0054] In one embodiment of the method, it is provided that a crucible holder which can be moved between a first position and a second position is formed in the sample chamber, and that The insertion of the sample crucible into the sample chamber is carried out by placing the sample crucible on a support surface of the crucible holder with the crucible holder in the first position; after placing the chamber cover on the chamber opening of the sample chamber and creating the gas atmosphere in the sample chamber, the hole is pierced in the crucible cover with the crucible holder in the first position; after piercing the hole in the crucible cover and before carrying out the thermal analysis of the sample, the crucible holder is moved from the first position to the second position.

[0055] The second position of the movable crucible holder is preferably located further away from the chamber opening and / or further inward in the device than the first position. In particular, the crucible holder can be moved vertically, with the second position being located further away from the chamber opening and / or further inward in the device (e.g., further down) than the first position.

[0056] In a further development, it is provided that the device has an additional chamber cover which can be placed on the chamber opening of the sample chamber instead of a cover / piercing unit, and that the removal of the cover / piercing unit from the chamber opening and its replacement by the other chamber cover takes place with the crucible holder in the second position.

[0057] A sample crucible with a crucible cover, specially designed for use in a device and / or process of the type described herein, may, for example, have: a sample crucible of at least approximately cylindrical shape with an interior for receiving the sample and with a crucible opening, a crucible cover that can be placed on or fitted onto the sample crucible at the crucible opening, the crucible cover features: a lid, in particular a screw lid, which can be connected or joined to an opening edge of the sample crucible, with a lid hole formed therein, and a pierceable sealing layer arranged on the inside of the lid, sealing the interior of the sample crucible.

[0058] Advantageously, in such a sample crucible with a crucible cover, the piercing of a hole in the crucible cover provided for in the inventive method can be carried out in such a way that the needle used for this purpose passes through the lid hole and then pierces the sealing layer underneath.

[0059] The cross-sections of the lid hole and the needle must be selected to match each other so that the needle, or at least one tip of the needle, fits through the lid hole. In one embodiment, the opening area of ​​the lid hole is larger by at least a factor of 2, and in particular by a factor of 4, than the maximum cross-sectional area of ​​a section of the needle or needle tip located in the area of ​​the lid hole during the piercing process. Alternatively, it is generally advantageous if this opening area of ​​the lid hole is larger by at most a factor of 10 than this maximum cross-sectional area of ​​the needle (tip).

[0060] The material and thickness of the sealing layer on the one hand, and the material and shape of the needle on the other, must be chosen to match each other so that the needle can penetrate the material of the sealing layer and thus pierce a hole in the sealing layer.

[0061] Advantageously, regardless of the design of the needle, the material and shape (especially, for example, thickness) of the lid can be chosen according to the desired mechanical stability of the lid, since during the piercing process the needle passes through the lid in the area of ​​the lid hole, which is designed, for example, as a suitably dimensioned bore.

[0062] The sample crucible may have a crucible body that is at least approximately in shape like a bowl or a pot.

[0063] In one embodiment, the sample crucible is made of a metal or metal alloy, such as steel, or tungsten, titanium, or aluminum (or an alloy thereof), wherein the surfaces bounding the interior of the sample crucible may be coated. Suitable materials for such a coating include, in particular, precious metals or precious metal alloys, such as gold or a gold alloy.

[0064] In one embodiment, the sample crucible has a circular base with a cylindrical or conical shell extending upwards from it in use. The base and the shell can, for example, be integrally joined. In this case, the opening of the sample crucible is defined by the upper edge of the shell.

[0065] The sample crucible can, for example, have a maximum lateral dimension in the range of 5 to 15 mm and / or a height in the range of 5 to 15 mm, preferably with a lateral dimension / height ratio in the range of 1.0 to 1.5. The wall thickness of the crucible body can, for example, be in the range of 0.5 to 1 mm.

[0066] The crucible cover, which is placed on or attached to the opening of the sample crucible, can, as already mentioned, have at least one lid and, underneath it (towards the interior of the sample crucible), a pierceable sealing layer. In one embodiment, the lid is made of a metallic material (metal or metal alloy) such as steel, titanium, or aluminum (e.g., the same material as the sample crucible).

[0067] In one embodiment, the lid is designed as a screw cap with a thread (internal or external thread) that can be screwed onto a corresponding thread (external or internal thread) of the sample crucible in the area of ​​the crucible opening.

[0068] In one embodiment, the pierceable sealing layer, arranged on the inside of the lid and sealing the interior of the sample crucible, is formed as a film made of a metallic material. Gold or a gold alloy, for example, is advantageously suitable as the material for the sealing layer. The thickness of the sealing layer can be, for example, in the range of 50 to 200 µm.

[0069] To achieve the sealing effect, it can be provided, for example, that an edge of the sealing layer is pressed all around by the lid onto an upper edge area of ​​the sample crucible, in other words, that it is clamped between the lid and the sample crucible.

[0070] In an advantageous further development, it is provided that the crucible cover also has a stabilizing layer arranged on the inside of the sealing layer with a stabilizing layer hole formed therein coaxially to the cover hole.

[0071] In this case, for example, it may be provided that an edge of the two-layer construction consisting of a sealing layer and a stabilizing layer arranged underneath is clamped all around between the lid and the sample crucible in order to achieve the sealing of the interior of the sample crucible.

[0072] In this advanced training, the stabilizing layer advantageously provides mechanical support for the sealing layer, so that when piercing the hole in the crucible cover (piercing the sealing layer), the sealing layer cannot retreat under load from the needle, thus achieving a better defined and reproducible geometry of the pierced hole.

[0073] By arranging the stabilization layer hole coaxially to the lid hole and thus coaxially to the needle during the insertion process, it is advantageously avoided that the insertion movement of the needle is hindered by the stabilization layer.

[0074] In one embodiment, the opening area of ​​the stabilizing layer hole is larger by at least a factor of 2, in particular by a factor of 4, than the maximum cross-sectional area of ​​a section of the needle or needle tip located in the area of ​​the stabilizing layer hole during the piercing process.

[0075] In one embodiment of the device according to the invention, this device comprises at least one sample crucible including a crucible cover of the type described herein.

[0076] A cover / piercing unit for a device for thermal analysis of a sample may, for example, comprise: a wall provided for covering the chamber opening; a guide bearing formed on the wall; and a needle movably mounted by means of the guide bearing, which extends from an inner side of the wall facing the sample chamber when the cover / piercing unit is in place, through the wall to an outer side of the wall facing away from the sample chamber when the cover / piercing unit is in place.

[0077] In such a covering / piercing unit, special embodiments and configurations can be provided, as already described here in connection with the device according to the invention.

[0078] According to another aspect of the invention, the use of a method of the type described herein for carrying out one or more thermal analyses of a sample is proposed, selected from the group consisting of thermogravimetric analysis (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC).

[0079] In one embodiment of this use, a simultaneous thermal analysis comprising one of the aforementioned analysis methods and at least one further analysis method is provided.

[0080] In an advantageous, more specific embodiment, the use for thermal analysis includes determining the mass of a sample during a temperature program using thermogravimetry (TG) and simultaneously determining the type and quantity of volatile decomposition products of the sample during this temperature program using mass spectrometry (MS or GC-MS).

[0081] In one embodiment, the temperature program defines a temperature inside the sample chamber (chamber temperature), for which the method may include, for example, measuring the chamber temperature and, based on this, controlling the temperature control device, preferably with a control (e.g., PID control) of the chamber temperature.

[0082] Alternatively, the temperature program can define a predetermined time profile of the sample temperature, for which the corresponding control (especially regulation) of the temperature control device can be carried out, e.g. based on the measured sample temperature.

[0083] Depending on the specific implementation of the method or the measuring device used, one or more additional parameters of the sample are measured, particularly parameters relating to the sample's properties. For example, when using thermogravimetry (TG), the weight or mass of the sample is measured as an additional parameter during a temperature change or a temperature program. Alternatively or additionally, another parameter can relate to the type and / or quantity of volatile products (e.g., determined using gas chromatography and / or mass spectrometry), and / or include at least one additional temperature and / or temperature difference (e.g., in DSC).Preferably, the method includes recording measurement data during the temperature program, in particular data representing the temperature-dependent and / or time-dependent profile of at least one temperature, chamber temperature and sample temperature (preferably both). By evaluating such data during the temperature control process and / or after completion of the temperature program, one or more material parameters of interest for the sample subjected to the method can be determined.

[0084] The invention is further described below with reference to exemplary embodiments and the accompanying drawings. These depict: Fig. 1 a sectional view of a device for thermal analysis of a sample according to an exemplary embodiment, Fig. 2 a somewhat simplified detail of the sectional view of Fig. 1 , namely a cover / piercing unit of the device of Fig. 1 , Fig. 3 a cutaway perspective view of the cover / pierce unit of Fig. 2 , Fig. 4 a perspective view of a hood part of the cover / piercing unit of the Fig. 2 and 3 Fig. 5 a schematic exploded view of a sample crucible with crucible cover according to an exemplary embodiment, Fig. 6 a top view of a lid of the crucible cover of Fig. 5 , Fig. 7 a top view of a stabilizing layer of the crucible cover of Fig. 5 , and Fig. 8 a sectional view of a device for thermal analysis of a sample according to a further embodiment.

[0085] Fig. 1 Figure 1 shows an embodiment of a device 10 for the thermal analysis of a sample. The device 10 has a sample chamber 12 for receiving a sample crucible 14 with a crucible cover 16 placed on it. During the thermal analysis, the sample to be analyzed is located inside the sample crucible 14.

[0086] The sample chamber 12 has a chamber opening 18 in an upper area of ​​the device 10, through which the sample crucibles 14 can be inserted into the sample chamber 12 to prepare for the analysis.

[0087] The device 10 further comprises a temperature control unit 20, by means of which the sample chamber 12, and thus the sample located in the sample crucible 14, is temperature-controlled during the analysis of the sample. In the illustrated example, the temperature control unit 20 has a hollow cylindrical heating jacket 22 (e.g., electric resistance heating).

[0088] In the illustrated embodiment, the device 10 is configured to carry out a method for thermal analysis of the sample, in which the sample is tempered according to a predetermined temperature program, during which a chamber temperature inside the sample chamber 12 is changed, wherein during the course of the temperature program a sample temperature and additionally one or more further measured quantities relating to properties of the sample are measured by means of a measuring device of the device 10.

[0089] In the illustrated embodiment, a thermogravimetric analysis (TG) is provided for the thermal analysis of the sample, in which (as a further measured variable) the change in the mass of the sample during the course of the temperature program is measured.

[0090] In the illustrated embodiment, the measuring device therefore comprises, in addition to a temperature measuring device for measuring the sample temperature, in particular a scale 26, by means of which the weight of the sample, including the components provided for receiving and storing the sample on the scale 26, is measured during the course of the temperature program. In this example, these components include, for example, the sample crucible 14 with its cover 16 and a sample crucible holder 28. By evaluating the weight measured by the scale 26 during the course of the temperature program, the temperature-dependent change in the mass of the sample is obtained.

[0091] To generate a defined gas atmosphere or gas flow in the sample chamber 12, the device 10 has a gas guidance system which, in the illustrated embodiment, has in particular a gas inlet 30 arranged in a lower region of the sample chamber 12. In the illustrated example, a further gas inlet 31 is arranged in the lower region of the sample chamber 12. A gas (e.g., nitrogen, argon, or helium, or a mixture containing at least one such inert gas) can be allowed to flow into this region of the sample chamber 12 via these gas inlets 30, 31.

[0092] In the example shown and in the Fig. 1 In the depicted situation, the gas supply device further comprises a gas outlet 32 ​​arranged in an upper region of the sample chamber 12, through which the protective gas can be allowed to flow out in this region of the sample chamber 12. In the example, the gas supply device of the apparatus 10 also includes a pressure sensor 34 for measuring a pressure in the sample chamber 12 and an overpressure relief valve (safety valve) 36, which releases gas from the sample chamber 12 in the event of excessive pressure.

[0093] To seal the sample chamber 12 of the device 10 gas-tight from the atmosphere (ambient air) during thermal analysis, the device 10 further comprises one or more (selectively) chamber covers that can be placed on the chamber opening 18 of the sample chamber 12. In the Fig. 1 In the situation shown, such a chamber cover 40 is placed on the chamber opening 18.

[0094] A special feature of the device 10 is that, in order to reduce the risk of an undesirable change to the sample as a result of chemical or physical reactions with components of the ambient air, the sample crucible 14 can be inserted into the sample chamber 12 in an airtight sealed state by means of the crucible cover 16 and opened there under a gas atmosphere generated by means of the gas guidance device.

[0095] For this purpose, the device 10 further comprises a piercing device 42, which is equipped with a needle 44 (e.g. made of steel or another metal alloy) and is designed to pierce a hole in the crucible cover 16 of the crucible 14 with the needle 44 when the sample crucible 14 is held in the sample chamber 12 and the chamber cover 40 is placed on the chamber opening 18.

[0096] In the example shown, the chamber cover 40 and the piercing device 42 are structurally combined as a cover / piercing unit 40, 42 and are in Fig. 1 The figure shows a situation in which, after the sample crucible 14 was inserted through the chamber opening 18 into the sample chamber 12, the cover / piercing unit 40, 42 was placed on the chamber opening 18.

[0097] In this situation, the said hole can be pierced in the crucible cover 16 of the sample crucible 14 using the needle 44.

[0098] In the illustrated embodiment, the cover / piercing unit 40, 42 has a wall 46 serving to cover the chamber opening 18 and a guide bearing 48 (sliding bearing) formed on the wall 46 for the movable support of the needle 44. The needle 44 extends from an inner side of the wall 46 facing the sample chamber 12 when the cover / piercing unit 40, 42 is in place, through the wall 46 to an outer side of the wall 46 facing away from the sample chamber 12 when the cover / piercing unit 40, 42 is in place.

[0099] In the example shown, a "drive of the needle" intended for the piercing process is achieved by a mechanical force acting on the section of the needle 44 located on the outside of the wall 46.

[0100] For this purpose, the piercing device 42 has a vertically movable weight 50 which can be dropped by a user from a predetermined height relative to the needle 44 onto a radial projection 52 formed on the shaft of the needle 44, thus positioning the needle 44 Fig. 1 to drive downwards and to pierce the said hole in the pot cover 16 by means of a needle tip 54 of the needle 44.

[0101] To predetermine the height from which the weight 50 is dropped onto the radial projection 52 of the needle 44, the illustrated example shows, for instance, a further radial projection 56 on the shaft of the needle 44. During the aforementioned manual operation, the user can first lift the weight 50, guided by the shaft of the needle 44, until it reaches the further radial projection 56, which serves as a stop, and then release the weight 50. Alternatively or additionally to the formation of a stop (projection 56) defining the drop height, one or more markings ("scale") could, for example, be provided on the shaft of the needle 44 to allow the weight 50 to be lifted to one or more predefined drop heights.

[0102] In the illustrated example, the piercing device 42 further comprises a spring assembly 58, which serves to preload the needle 44 against its piercing direction and is designed in the illustrated example as a spiral compression spring surrounding the shaft of the needle 44, which is supported on one side by the wall 46 and on the other side by the radial projection 52 of the needle 44. Advantageously, the piercing process of the needle 44 can thus be carried out with a well-defined, reproducible piercing depth, the extent of which ultimately depends on the characteristics of the spring assembly 58, the drop height and the mass of the weight 50, and the properties of the needle tip (material, geometry) in conjunction with properties of the crucible cover 16 to be pierced (e.g., material and thickness of a sealing layer to be pierced).

[0103] In contrast to the illustrated embodiment, the piercing device 42 could, for example, also have a mechanical stop to limit the piercing depth of the needle 44.

[0104] Within the scope of the invention, it has proven to be mostly advantageous if the chamber cover 40 with its wall 46 forms a (dome-like) "hood part" (cf. e.g. Fig. 4 ) forms such that, by placing the chamber cover 40 or, in the illustrated example, the cover / piercing unit 40, 42, the sample chamber 12 is expanded in a dome-like shape in the area of ​​the chamber opening 18. In this case, a gas outlet of the chamber cover 40 is preferably arranged in a distal area of ​​the hood shape (as is the case for the gas outlet 32 ​​provided in the illustrated example).

[0105] In the illustrated example, the piercing device 42 further comprises a mechanical centering device 60 ("centering aid") by means of which the sample crucible 14, including the crucible cover 16, is centered with respect to the piercing device 42 and thus the needle 44 before the piercing process is carried out. Advantageously, the piercing of the crucible cover 16 thus takes place at a well-defined location on the crucible cover 16.

[0106] In the illustrated example, the centering device 60 of the cover / piercing unit 40, 42 is formed by several centering jaws 62, which are arranged on the inside of the wall 46 and are, for example, integrally formed with the wall 46, such that during the piercing process they contact a lateral surface of the sample pot 14 and / or a lateral surface of the pot cover 16 in order to force the sample pot 14 together with the pot cover 16 into a specific position relative to the needle 44 (centering) before the hole is pierced in the pot cover 16 of the sample pot 14 by means of the needle 44.

[0107] Furthermore, the movable crucible holder in the illustrated example has the advantage that the sample crucible 14, including the already pierced crucible cover 16, can be moved from the first position to the second position before the cover / piercing unit 40, 42 is removed from the chamber opening 18 of the sample chamber 12 in the second position and replaced by the other chamber cover. Since the sample crucible 14 is located further down in the second position and thus further away from the chamber opening 18, where a certain amount of gas exchange between the gas atmosphere and ambient air is unavoidable in practice after the removal of the cover / piercing unit 40, 42, the sample is even better protected from contact with ambient air during this sample preparation phase (replacement of the chamber cover).

[0108] Fig. 2 shows, enlarged and somewhat schematically simplified, the cover / piercing unit 40, 42 from the sectional view of Fig. 1 .

[0109] Fig. 3 shows a cutaway perspective view of the cover / pierce unit 40, 42.

[0110] Fig. 4 shows a perspective view of a "hood part" of the cover / piercing unit 40, 42 of the Fig. 2 and 3 , comprising the wall 46 and the centering device 60 formed by several centering jaws 62.

[0111] If the chamber cover is not used during thermal analysis, apart from its function of protecting against the exchange of media and / or energy (heat) between sample chamber 12 and the environment (in Fig. 1 Since the cover / piercing unit 40, 42 above has an additional function, it is advantageous if, after piercing the hole in the crucible cover 16 and before performing the thermal analysis of the sample, the cover / piercing unit 40, 42 is replaced by a chamber cover optimized with respect to the aforementioned additional function(s). Such an additional function could, for example, be to provide a carrier gas outlet through which gas acting as a carrier gas during the thermal analysis of the sample, along with gaseous components originating from the sample, is conveyed from the sample chamber 12 to an analysis device (e.g., comprising a mass spectrometer).

[0112] In the illustrated embodiment, the device 10 therefore has a further chamber cover (not shown) which can be placed on the chamber opening 18 of the sample chamber 12 instead of the cover / piercing unit 40, 42 and which, similar to the gas outlet 32 ​​of the cover / piercing unit 40, 42, has a gas outlet to which a gas line leading to an analysis device can be connected or is connected.

[0113] A method for thermal analysis of the sample carried out using the device 10 may in particular include the following steps: Insertion of the sample crucible 14, including the crucible cover 16 and the sample contained therein, through the chamber opening 18 of the sample chamber 12 into the sample chamber 12; placement of the cover / piercing unit 40, 42 onto the chamber opening 18 of the sample chamber 12; creation of a gas atmosphere in the sample chamber 12 by means of the gas guidance device 30, 31, 32; piercing of a hole in the crucible cover 16 of the sample crucible 12 by means of the piercing device 42 of the cover / piercing unit 40, 42; performance of the thermal analysis of the sample by means of the temperature control device 20 for temperature control of the sample chamber 12 according to a predetermined temperature program (time-dependent temperature profile) and the measuring device for measuring the sample temperature and the mass change of the sample.

[0114] If the procedure for the thermal analysis of the sample simultaneously with thermogravimetry (TG) provides for a time-dependent determination of the type and quantity of volatile decomposition products of the sample during the course of the relevant temperature program by means of mass spectrometry (MS), the cover / piercing unit 40, 42 is removed from the chamber opening 18 of the sample chamber 12 after the hole has been pierced in the crucible cover 16, but before the thermal analysis of the sample is carried out, and replaced by another chamber cover mentioned above, on which a gas outlet is formed, through which the volatile decomposition products of the sample are led to a mass spectrometer during the thermal analysis.

[0115] In this process, a gas flow through the sample chamber 12 is effected by means of the gas guidance device, in that the gas in question, which can also be referred to as a carrier gas with regard to its function in connection with mass spectrometry, is admitted at a predetermined flow rate in the lower area of ​​the sample chamber 12 at the gas inlet 30 and / or 31 and is released in the upper area of ​​the sample chamber 12 at the gas outlet of the chamber cover (possibly e.g. via a separation column of a gas chromatography device) towards the mass spectrometer.

[0116] In a very similar way, such a gas flow through the sample chamber 12 can already be provided during the sample preparation phases preceding the actual analysis, namely when the sample crucible 14 is inserted into the sample chamber 12 and when the cover / piercing unit 40, 42 is removed from the chamber opening 18 and the other chamber cover is subsequently placed on the chamber opening 18.

[0117] In this context, it is advantageous that the cover / piercing unit 40, 42, as already mentioned with reference to Fig. 1 The device has a gas outlet 32 ​​through which, when the cover / piercing unit 40, 42 is placed on the chamber opening 18, the gas flowing into the sample chamber 12 via the gas inlet 30 of the device 10 can escape from the sample chamber 12 to the outside environment. This allows the air to be advantageously and quickly displaced from the sample chamber 12 after the cover / piercing unit 40, 42 is placed and replaced by the gas atmosphere ("protective gas atmosphere"), in which the crucible cover 16 can then be opened (by piercing with the needle 44).

[0118] It is preferably provided that the gas flow through the sample chamber 12 effected by means of the gas guidance device is such that its flow rate during the insertion of the sample crucible 14 into the sample chamber 12 and / or during the replacement of the cover / piercing unit 40, 42 by the other chamber cover is higher (e.g. by at least a factor of 2) than during the performance of the thermal analysis.

[0119] Returning to Fig. 1 In the embodiment of the device 10 shown therein, the sample crucible carrier 28 or its Fig. 1 The upper end is formed as a crucible holder with a support surface for placing the sample crucible 14 on it, wherein in this example a special feature is that this crucible holder is movable in the vertical direction between a in Fig. 1 The first position shown is for setting down the sample crucible 14 and for piercing the hole in the crucible cover 16, and a second position (not shown) for carrying out the thermal analysis of the sample.

[0120] In this second position, the sample crucible 14 is located approximately in the center of the heating jacket 22 of the temperature control unit 20 for the purpose of carrying out the thermal analysis. The second position of the movable crucible holder or the movable sample crucible support 28 is therefore further down than the one in Fig. 1 The first position shown is provided, i.e. further away from the chamber opening 18 and further inwards in the device 10.

[0121] In the first position, the insertion and placement of the sample crucible 14, held e.g. with tweezers, into the device 10 (through the chamber opening of the sample chamber 12) is simplified, whereas in the second position precise temperature control of the sample during thermal analysis can be ensured.

[0122] Furthermore, the movable crucible holder in the illustrated example has the advantage that a mechanical load caused by piercing the hole in the crucible cover 16 of the sample crucible 14 is not transferred to the balance 26 used in this example for thermogravimetric analysis (TG). Specifically, in the first position, the sample crucible holder 28 is raised upwards by means of a lifting device 70 and thus mechanically decoupled from the balance 26. Only after the hole has been pierced in the crucible cover 16, but before the thermal analysis is carried out, is the sample crucible holder 28 lowered downwards by means of the lifting device 70 and thus placed on the balance 26.

[0123] Furthermore, the movable crucible holder in the illustrated example has the advantage that the sample crucible 14, including the already pierced crucible cover 16, can be moved from the first position to the second position before the cover / piercing unit 40, 42 is removed from the chamber opening 18 of the sample chamber 12 in the second position and replaced by the other chamber cover. Since the sample crucible 14 is located further down in the second position and thus further away from the chamber opening 18, where a certain amount of gas exchange between the gas atmosphere and ambient air is unavoidable in practice after the removal of the cover / piercing unit 40, 42, the sample is even better protected from contact with ambient air during this sample preparation phase (replacement of the chamber cover).

[0124] Since the illustrated embodiment features a crucible holder (sample crucible carrier 28) that can be moved between the first position and the second position, the method carried out with the device 10 can therefore advantageously provide that the insertion of the sample crucible 14 into the sample chamber 12 is carried out by placing the sample crucible 14 on a support surface of the crucible holder provided at the upper end of the sample crucible carrier 28 with the crucible holder in the first position, that after placing the chamber cover (in the example: cover / piercing unit 40, 42) on the chamber opening 18 of the sample chamber 12 and generating a defined gas atmosphere (and preferably gas flow) in the sample chamber 12, the hole is pierced in the crucible cover 16 with the crucible holder in the first position, and that after piercing the hole in the crucible cover 16 and before carrying out the thermal analysis of the sample, the crucible holder is moved from the first position to the second position.

[0125] In the following description of further embodiments, the same reference numbers are used for identically functioning components, each supplemented by a lowercase letter to distinguish the embodiment. Essentially, only the differences from the embodiment(s) already described are addressed, and otherwise, reference is expressly made to the description of the preceding embodiments.

[0126] The following refers to the Fig. 5 bis 7 An embodiment of a sample crucible 14a with a crucible cover 16a, which can be used particularly advantageously in a method according to the invention, is described.

[0127] Fig. 5 shows the sample crucible 14a with crucible cover 16a in a schematic exploded view from the side.

[0128] The sample crucible 14a has a cylindrical shape with an interior for receiving the sample and with a crucible opening 80a on an upper end face of this cylindrical shape.

[0129] The crucible cover 16a, which is placed on or attached to the crucible opening 80a of the sample crucible 14a, consists in the illustrated example of a lid 82a, a pierceable sealing layer 84a (sealing film) and a stabilizing layer 86a.

[0130] The lid 82a is designed as a screw-on lid and can be connected (here: screwed on) to an opening rim of the sample crucible 14a around its entire circumference. In this example, the lid 82a has an internal thread on its circumferential rim that can be screwed onto a corresponding external thread of the sample crucible 14a. The lid 82a also has a centrally located lid hole 88a that passes through the lid 82a.

[0131] The penetrable sealing layer 84a is arranged on the inside of the lid 82a in the assembled state of the "sample pot / pot cover combination" 14a, 16a and serves in this state to seal the interior of the sample pot 14a.

[0132] The stabilizing layer 86a is arranged on the inside of the penetrable sealing layer 84a in the assembled state. Furthermore, the stabilizing layer 86a has a stabilizing layer hole 90a arranged coaxially to the cover hole 88a and passing through the stabilizing layer 86a.

[0133] In the assembled state of the sample pot / pot cover combination 14a, 16a, an edge of the two-layer construction consisting of sealing layer 84a and stabilizing layer 86a arranged below it is clamped all around between the lid 82a and the sample pot 14a.

[0134] In the illustrated example, the sample crucible 14a is formed in one piece (base and body) from steel, with the interior surfaces coated with a gold alloy. The crucible cover 16a, in the illustrated example, consists of steel (lid 82a) and a gold alloy (sealing layer 84a and stabilizing layer 86a).

[0135] In the case of the sample crucible 14a with crucible cover 16a, the piercing of a hole in the crucible cover 16a can advantageously be carried out in such a way that the needle used for this purpose (e.g. needle 44) is inserted into the Fig. 1 bis 4 The needle passes through the cover hole 88a and then pierces the sealing layer 84a located underneath. The stabilizing layer 86a advantageously provides mechanical support for the sealing layer 84a, preventing it from yielding under the pressure of the needle when the hole is pierced, thus ensuring a well-defined and reproducible hole geometry. The provision of the stabilizing layer hole 90a advantageously prevents the needle's piercing motion from being obstructed by the stabilizing layer 86a.

[0136] Fig. 6 shows a top view of the lid 82a of the crucible cover 16a.

[0137] Fig. 7 shows a top view of the stabilization layer 86a of the crucible cover 16a.

[0138] The diameters of the cover hole 88a and the stabilizing layer hole 90a, on the one hand, and of the needle, on the other hand, are to be selected to match each other so that the needle, or at least one tip of the needle, fits through the cover hole 88a and preferably also through the stabilizing layer hole 90a. In the example shown, the diameters of the cover hole 88a and the stabilizing layer hole 90a are the same size and each has a diameter of approximately 0.5 mm.

[0139] Fig. 8 shows a further embodiment of a device 10b for the thermal analysis of a sample. As already mentioned with reference to Fig. 1 The described device 10 comprises a sample chamber 12b for receiving a sample crucible 14b with a crucible cover 16b placed thereon, wherein the sample to be analyzed is located inside the sample crucible 14b. The sample chamber 12b has a chamber opening 18b in an upper region of the device 10b, through which the sample crucible 14b can be inserted into the sample chamber 12b to prepare for analysis. The device 10b further comprises a temperature control device 20b, by means of which the sample chamber 12b is temperature-controlled according to a predetermined temperature program during the analysis of the sample. During this program, the chamber temperature inside the sample chamber 12b is changed, and a measuring device of the device 10b measures the sample temperature and, additionally, one or more other measurable parameters relating to the properties of the sample.

[0140] Unlike device 10 of Fig. 1 The device 10b is designed to perform a thermal analysis of the sample, including the method of differential scanning calorimetry (DSC).

[0141] In this case, sample chamber 12b contains two sample crucible holders 28b-1 and 28b-2, which function as "sensors" and are equipped with thermocouples for temperature measurement. Each crucible of the type described can be placed on one of these holders. During the DSC procedure, both sample crucibles, or possibly two samples simultaneously (e.g., the "actual sample" and a "reference sample"), are subjected to simultaneous temperature control in sample chamber 12b. Alternatively, instead of simultaneously temperature controlling two samples, the second crucible can also be used "empty" (i.e., without a sample or reference sample) during the procedure.

[0142] The measuring device of the apparatus 10b therefore includes a temperature measuring device for measuring the temperatures of both the actual sample (in the sample crucible 14b) and the reference sample (or an "empty" second sample crucible).

[0143] Each of the sample crucible supports 28b-1, 28b-2 serves, in the operating situation of the device 10b, to allow a sample crucible, such as the illustrated sample crucible 14b, to be positioned on it in order to define the arrangement of the sample crucible, including any sample it may contain (including a "reference sample"), in the sample chamber 12b, and to measure the temperature at the bottom of the respective crucible, i.e., the sample temperature (in the case of crucible 14b containing the sample). For this purpose, a thermocouple (not shown in the figure) is arranged on the surface or inside each sample crucible support 28b-1, 28b-2.

[0144] In the dynamic differential calorimetry performed using the device 10b, the evaluation of a measurement result (measurement data) specifically determines a time-dependent profile of the difference between the temperatures measured by the two sensors (sample crucible carriers 28b-1, 28b-2), particularly to determine energetic effects and / or, for example, a temperature-dependent specific heat capacity of the sample. In a further development of the device 10b (not shown), a combination of DSC with at least one other thermoanalytical method, such as, for example, TG (thermogravimetric analysis), could be provided.

[0145] As with the device 10 already described above ( Fig. 1 ) are also present in device 10b ( Fig. 8 ) a chamber cover 40b and the piercing device 42b are structurally combined as a cover / piercing unit 40b, 42b, which again has a wall 46b, a guide bearing 48b formed thereon, and a needle 44b movably mounted therein.

[0146] Unlike device 10 ( Fig. 1 ) is in device 10b ( Fig. 8 ), in adaptation to the "eccentric" position of the crucible cover 16b to be pierced of the sample crucible 14b, the guide bearing 48b and thus the needle 44b are not arranged in the center of the (e.g. circular) chamber cover 40b but eccentrically.

[0147] In summary, the invention and the described embodiments make it possible to insert an airtight sealed sample crucible into a device for thermal analysis of a sample under inert gas conditions and only open it there under inert gas conditions. Advantageously, this drastically reduces the risk of sample alteration due to undesirable chemical or physical reactions with components of the ambient air during sample preparation.

Claims

1. Device (10) for thermal analysis of a sample, comprising - a sample chamber (12) for receiving a sample crucible (14) with a crucible cover (16) placed thereon for airtight sealing of the sample crucible (14), inside which there is a sample to be analyzed, wherein the sample chamber (12) has a chamber opening (18) for inserting the sample crucible (14) in its sealed state into the sample chamber (12), - a temperature controlling means (20) for controlling the temperature of the sample chamber (12), - a measuring means for measuring the temperature of the sample and one or more other measurement quantities, - a gas guiding means (30, 31, 32) for generating a defined gas atmosphere in the sample chamber (12) after the sample crucible (14) in its sealed state has been inserted into the sample chamber (12), - a chamber cover (40) that can be placed on the chamber opening (18) of the sample chamber (12), - a piercing means (42) having a needle (44) that is suitable for piercing a hole in the crucible cover (16) of the sample crucible (14) with the needle (44) when the sample crucible (14) in its sealed state is received in the sample chamber (12) and the chamber cover (40) is placed on the chamber opening (18), in order to open the sample crucible (14) under the defined gas atmosphere by perforating the crucible cover (16).

2. Device (10) according to claim 1, wherein the chamber cover (40) and the piercing means (42) are structurally combined to form a cover / piercing unit (40, 42).

3. Device (10) according to claim 2, wherein the device (10) has an additional chamber cover (40) which can be placed on the chamber opening (18) of the sample chamber (12) instead of the cover / piercing unit (40, 42).

4. Device (10) according to claim 2 or 3, wherein the cover / piercing unit (40, 42) comprises: - a wall (46) provided for covering the chamber opening (18), - a guide bearing (48) formed at the wall (46) for movably supporting the needle (44), wherein the needle (44) extends from an inner side of the wall (46) facing the sample chamber (12) when the cover / piercing unit (40, 42) is placed, through the wall (46) to an outer side of the wall (46) facing away from the sample chamber (12) when the cover / piercing unit (40, 42) is placed.

5. Device (10) according to any one of the preceding claims, wherein the piercing means (42) has a mechanical stop for limiting a piercing depth of the needle (44).

6. Device (10) according to any one of the preceding claims, wherein the piercing means (42) comprises a mechanical centering means (60) for centering the sample crucible (14) together with the crucible cover (16) with respect to the needle (44).

7. Device (10) according to any one of the preceding claims, wherein a crucible receptacle with a support surface for placing the sample crucible (14) thereon is formed in the sample chamber (12), and wherein the crucible receptacle is movable between a first position for placing the sample crucible (14) and piercing a hole in the crucible cover (16) and a second position for performing the thermal analysis of the sample.

8. Method for thermal analysis of a sample which is located inside a sample crucible (14) with a crucible cover (16) placed thereon, in particular using a device (10) according to any one of the preceding claims, comprising the following steps: - Inserting the sample crucible (14) with the crucible cover (16) placed thereon for airtight sealing of the sample crucible (14) through a chamber opening (18) of a sample chamber (12) into the sample chamber (12), - Placing a chamber cover (40) on the chamber opening (18) of the sample chamber (12) and generating a defined gas atmosphere in the sample chamber (12) by means of a gas guiding means (30, 31, 32) after the sample crucible (14) in its sealed state has been inserted into the sample chamber (12), - Piercing a hole in the crucible cover (16) of the sample crucible (14) received in its sealed state in the sample chamber (12) by means of a piercing means (42) in order to open the sample crucible (14) under the defined gas atmosphere by perforating the crucible cover (16), - Performing the thermal analysis of the sample using a temperature controlling means (20) for controlling the temperature of the sample chamber (12) and a measuring means for measuring a temperature of the sample and one or more other measurement quantities.

9. Method according to claim 8, wherein the chamber cover (40) and the piercing means (42) are structurally combined to form a cover / piercing unit (40, 42), and wherein, after piercing the hole in the crucible cover (16) and before performing the thermal analysis of the sample, the cover / piercing unit (40, 42) is removed from the chamber opening (18) of the sample chamber (12) and replaced by another chamber cover.

10. Method according to claim 9, wherein the gas atmosphere is generated by a gas flow through the sample chamber (12) effected by means of the gas guiding means (30, 31, 32), the flow rate of which during the replacement of the cover / piercing unit (40, 42) with the other chamber cover is higher than during performance of the thermal analysis.

11. Use of a method according to any one of claims 8 to 10 for performing one or more thermal analyses of a sample selected from the group consisting of thermogravimetric analysis, differential thermal analysis, and dynamic differential calorimetry.