Apparatus and method for thermal analysis of a sample

Abstract

The present invention relates to a thermal analysis of a sample and provides a device (10) for performing thermal analysis on a sample, comprising: a sample chamber (12) for accommodating a sample crucible (14) on which a crucible cover (16) is placed, and a sample to be analyzed is located inside the sample crucible, wherein the sample chamber (12) has a chamber opening (18) for placing the sample crucible (14) into the sample chamber (12); a temperature regulating device (20) for regulating the temperature of the sample chamber (12); and a measuring device for measuring the temperature of the sample chamber (12). The invention also provides a method for thermally analyzing a sample, a sample crucible (14) having a crucible cover (16) and a covering / piercing unit (40, 42).

Description

Technical Field

[0001] The invention relates to a device and a method for thermal analysis of a sample, a sample crucible with a crucible cover which can be used therein, and a covering / piercing unit which can be used for such a device. Background Art

[0002] Devices for thermal analysis of samples are known in various embodiments from the prior art and have a sample chamber for accommodating (at least one) sample to be analyzed or for accommodating (at least one) sample crucible, the sample to be analyzed being located inside the sample crucible. In addition, the device has a temperature control device for temperature control of the sample chamber and a measuring device for measuring the sample temperature and one or more other measured variables.

[0003] Methods for thermal analysis can be advantageously used, for example, for the characterization of material properties (e.g. specific heat capacity, thermal conductivity, melting temperature, decomposition temperature and crystallization temperature), including, for example, temperature-dependent properties or processes occurring during temperature changes (e.g. enthalpy during phase changes or chemical reactions, etc.).

[0004] Examples of methods for thermal analysis are derivative methods such as thermogravimetric analysis (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC).

[0005] For methods of particular interest within the scope of the present invention, the sample is usually temperature-regulated according to a temperature program, in which the chamber temperature in the sample chamber is varied and the sample temperature and one or more other measured variables of the sample which are additionally related to the sample properties are simultaneously measured by means of a measuring device.

[0006] For thermogravimetric analysis (TG), during a temperature program, for example the weight or mass of a sample is measured as such a “property of the sample”.

[0007] Depending on the specific design of the measuring device, for thermal analysis, in addition to the measurement of the sample temperature and, for example, the sample mass, various measurements of other physical quantities can in principle also be provided during the temperature program.

[0008] An example of this is the determination of the temperature-dependent thermal effect of a sample by means of DSC and, at the same time, the temperature-dependent mass of the sample by means of thermogravimetric analysis (TG). Another example is the determination of the type and amount of volatile decomposition products of a sample by means of mass spectrometry (MS) during a temperature program and, at the same time, the temperature-dependent mass of the sample by means of thermogravimetric analysis (TG). Thermal analysis using several different methods at the same time is also referred to as "simultaneous thermal analysis".

[0009] Therefore, the term "property of the sample" (measured by the measuring device) as used herein should be understood very broadly and may include, for example, the "type and amount" of the above-mentioned volatile decomposition products.

[0010] For certain materials and samples produced therefrom, the problem arises that the samples can become contaminated by atmospheric components such as oxygen, carbon dioxide, water (humidity), etc. and / or chemically react with these components, thereby changing the relevant sample in an undefined way.

[0011] With regard to the storage and / or transport of the samples, a simple solution to this problem is to "pack" the samples immediately after their production in a sample crucible with a gas-tight crucible cover mounted thereon, or to prepare the samples in a sample crucible and to provide the crucible with a gas-tight crucible cover immediately thereto.

[0012] However, even if the sample is placed in a sample crucible with a gas-tight crucible cover on it, the above-mentioned risks of contamination and / or chemical reactions still exist once the sample has been placed in the device within the scope of so-called "sample preparation" and here the crucible cover has to be removed or otherwise opened in preparation for the thermal analysis, which is mandatory for many thermal analyses.

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

[0014] Apart from this very complicated and, for cost reasons, rather impractical solution, the problem can be alleviated to a certain extent 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 a small hole can be pierced, e.g. with a needle, in order to create a media-permeable connection between the interior of the sample crucible and the sample chamber of the device for subsequent thermal analysis.

[0015] However, even in this manner, i.e. the crucible cover is "pierced" in the ambient air, there is still a certain risk of contamination and / or chemical reactions with components of the ambient air during the introduction of the sample into the device. Summary of the invention

[0016] One object of the present invention is to reduce the existing risk of sample changes due to undesired chemical or physical reactions within the scope of sample preparation in an apparatus and a method for thermal analysis.

[0017] According to a first aspect of the present invention, the object is achieved by a device for thermal analysis of a sample, the device having:

[0018] a sample chamber for accommodating a sample crucible with a crucible cover thereon, the sample to be analyzed being located inside the sample crucible, wherein the sample chamber has a chamber opening for inserting the sample crucible into the sample chamber,

[0019] - a temperature regulating device for regulating the temperature of the sample chamber,

[0020] - a measuring device for measuring the temperature of the sample and one or more other measured variables,

[0021] - a gas guiding device for generating a gas atmosphere in the sample chamber,

[0022] - a chamber cover, which can be placed on the chamber opening of the sample chamber,

[0023] A piercing device equipped with a needle, which is suitable for piercing a hole in the crucible cover of the sample crucible with the needle when the sample crucible is accommodated in the sample chamber and the chamber cover is placed on the chamber opening.

[0024] The invention has the advantage that, since the sample crucible can be placed in a closed state in the sample chamber and there can be opened under a defined gas atmosphere, the risk of undesired changes in the sample due to chemical or physical reactions with components of the ambient air can be significantly reduced.

[0025] In a preferred embodiment of the invention, it is provided that the gas atmosphere generated in the sample chamber contains at least one gas selected from the group consisting of nitrogen, argon and helium. For its purposes, this gas atmosphere can also be referred to as an inert gas atmosphere or a protective gas atmosphere.

[0026] In many conventional thermal analysis devices and methods, it is provided that during the thermal analysis a so-called carrier gas flows through the sample chamber in order to discharge 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 a measuring device (e.g. a gas chromatograph / mass spectrometer).

[0027] In this case, it can be provided that at least part of the means for generating a carrier gas flow in the sample chamber (e.g. a gas source, a gas inlet, etc.) is also used in addition to the gas atmosphere in the sample chamber within the scope of the sample preparation. The composition of the gases during the sample preparation on the one hand ("protective gas") and during the performance of the thermal analysis on the other hand ("carrier gas") can be selected to be identical or different from one another.

[0028] In one embodiment of the invention, it is provided that the chamber cover and the puncture device are structurally combined to form a covering / puncture unit.

[0029] This results in the advantage for many device designs that are already in use that the invention can be implemented simply and cost-effectively by relatively minor modifications to the design.

[0030] In a variant of this embodiment, it is provided that the device has a further chamber cover which can be placed on the chamber opening of the sample chamber instead of on the covering / piercing unit.

[0031] For example, if the chamber cover has at least one other function in addition to the function of protecting the medium and / or energy (heat) exchange between the sample chamber and the environment when performing thermal analysis, then this variant is particularly advantageous. According to this variant, the covering / piercing unit can be replaced by a chamber cover optimized with respect to the aforementioned other function after the puncture hole in the crucible cover and before performing thermal analysis of the sample. This other function can be, for example, providing a gas outlet through which a gas acting as a carrier gas is conveyed from the sample chamber to an analysis unit of a measuring device (e.g. a gas chromatograph / mass spectrometer) in the thermal analysis of the sample together with the gas components from the sample.

[0032] In another variant of this embodiment, it is provided that the covering / piercing unit has a gas outlet (eg at least one small opening) through which gas from the gas atmosphere of the sample chamber can flow outwardly into the environment when the covering / piercing unit is mounted on the chamber opening.

[0033] With this variant, it is advantageously possible to achieve a rapid and complete exhaust of air from the sample chamber immediately after the covering / piercing unit has been installed, wherein a gas atmosphere is created by a gas flow in the sample chamber with the aid of a gas guiding device, wherein the gas flows into the sample chamber, for example, at a position relatively far from the chamber opening and flows out at the gas outlet of the covering / piercing unit.

[0034] If, at this stage of sample preparation (where it is advantageous to continue to flow gas), a hole is then punctured in the crucible cover and the covering / puncturing unit is then removed from the chamber opening of the sample chamber (in order to replace it with another chamber cover before performing the thermal analysis), a gas flow in the sample chamber in this direction is prevented or minimized, i.e. ambient air is advantageously infiltrated into the sample chamber from the interior of the device for the chamber opening of the sample chamber.

[0035] The covering / puncturing unit can, for example, have a wall provided for covering the chamber opening and a guide bearing designed on the wall for a bearing of a movable needle, wherein the needle can extend from the inner side of the wall facing the sample chamber when the covering / puncturing unit is placed, through the wall to the outer side of the wall facing away from the sample chamber when the covering / puncturing unit is placed.

[0036] In the latter case, it can be provided, for example, that the "driving of the needle" for the puncturing process is realized by a mechanical action (thrust) on the part of the needle located outside the wall. This has the advantage, for example, that no corresponding drive components in the sample chamber are required to drive the needle. Instead, these drive components can be arranged on the outside of the covering / puncturing unit without affecting the sample chamber and without problems with installation space.

[0037] If a vertical puncturing movement of the needle from top to bottom is provided in the use of the device, then in many cases, in particular a very simple embodiment of a covering / puncturing unit which can be operated manually and therefore has a wall provided for covering the opening of the chamber and a guide bearing designed on the wall for movable support of the needle, wherein the needle extends through the wall from the above-mentioned inner side of the wall to the above-mentioned outer side of the wall, and wherein the covering / puncturing unit also has a weight on the covering / puncturing unit which can be guided in vertical movement and which can be dropped from a predetermined height relative to the needle to the distal end of the needle or to another position on the needle by manual operation of the user.

[0038] As an alternative to a manual operation, by means of which the weight can be raised to a predetermined height and then lowered, it is also conceivable to equip the piercing device or the covering / piercing unit with an electric device suitable for this purpose.

[0039] Instead of using a falling weight (where a falling weight is used to generate the generally advantageous relatively fast insertion movement of the needle), it is also considered to provide an electric device that acts on the needle via a gear connection to drive its insertion movement. With such an embodiment, it is particularly possible to provide a relatively slow insertion movement of the needle.

[0040] The optimum insertion movement (eg fast or slow, short or long stroke) and the optimum shape of the needle for piercing the crucible cover, in particular the optimum shape of its tip, can be determined depending on the application (design of the crucible cover), for example empirically.

[0041] In one embodiment, the needle has a rotationally symmetrical shape (e.g. a cylindrical shaft with a tapered tip) at least in the region of its tip and in the region of the shaft adjacent thereto. For a tapered tip, the angle defined from the tip when viewed from the side can, for example, be in the range of 5° to 60°, in particular in the range of 10° to 30°.

[0042] In one embodiment of the invention, it is provided that the puncture device has a mechanical stop to limit the puncture depth of the needle. Alternatively or additionally, it can be provided, for example, that the puncture device has a spring device which preloads the needle into its puncture direction, whereby, for example, in the case of the above-described embodiment with a falling weight, a defined puncture depth can also be achieved.

[0043] In one embodiment of the invention, it is provided that the piercing device has a mechanical centering device for centering the sample crucible including the crucible cover relative to the needle.

[0044] The centering device can, for example, have two or more centering claws for contacting the outer surface of the sample crucible or a crucible cover placed thereon in order to force the sample crucible and the crucible cover into a specific position (centering) relative to the needle before the hole is inserted into the crucible cover of the sample crucible by means of the needle of the piercing device.

[0045] In one embodiment of the invention, a crucible receptacle having a storage surface is provided in the sample chamber for storing a sample crucible thereon, wherein the crucible receptacle is movable between a first position for storing the sample crucible and piercing a hole in the crucible cover and a second position for performing a thermal analysis of the sample.

[0046] In this case, the second position of the movable crucible receptacle is preferably arranged further away from the chamber opening and / or “closer to the interior of the device” than the first position.

[0047] In a more specific embodiment, a vertical movability of the crucible receptacle is provided, wherein the second position is arranged further away from the chamber opening and / or “closer to the interior of the device” than the first position.

[0048] Although a movable crucible receptacle is usually also provided with devices known from the prior art, this serves primarily to simplify the insertion and storage of a sample crucible, which is held in the device, for example with tweezers (for example through a relatively small chamber opening of the sample chamber), taking into account that in order to ensure the most precise possible temperature regulation of the sample to be analyzed in the sample chamber, the sample usually has to be located "further inside" in the device during the subsequent analysis.

[0049] However, within the scope of the invention, the above-mentioned movable crucible receptacle achieves additional advantages, for example, that the design of the piercing device, whether structurally combined with the chamber cover (as a covering / piercing unit) or separated from the chamber cover becomes easier.

[0050] Furthermore, the above-mentioned movable crucible receptacle can be separated from mechanically sensitive components of the device (eg a scale for thermogravimetric analysis (TG)) from mechanical loads caused by puncturing a hole in the crucible cover of the sample crucible.

[0051] Another advantage of the embodiment with a movable crucible receptacle is that the device has a further chamber cover which can be placed on the chamber opening of the sample chamber instead of the covering / piercing unit. In this case, it can be provided that the sample crucible is moved together with the already pierced crucible cover from a first position (for storing the sample crucible and piercing the crucible cover) into a second position, which is arranged "further inside" (e.g. sunk into the device) or at least further away from the chamber opening relative to the first position, before the covering / piercing unit is removed from the chamber opening of the sample chamber (in the second position of the crucible receptacle) and replaced by the further chamber cover.

[0052] Because the sample crucible in the second position is located further inside or at least further away from the chamber opening, a certain exchange between the gas atmosphere and the ambient air can occur at the chamber opening after removing the covering / piercing unit, the sample is particularly well protected from contact with the ambient air at this stage (replacing the chamber cover).

[0053] In this case, it should also be noted again that the above-mentioned protective gas flow from the sample chamber inside the device for the chamber opening of the sample chamber advantageously already acts to protect the sample from contact with the ambient air. However, this protection is also advantageously increased by moving the sample crucible (with the crucible cover that has been pierced) from the first position to the second position, thereby further away from the chamber opening.

[0054] According to another aspect of the invention, the first object is achieved by a method for thermal analysis of a sample located inside a sample crucible having a crucible cover thereon, in particular using a device of the type described herein, wherein the method comprises the following steps:

[0055] - placing the sample crucible into the sample chamber through the chamber opening of the sample chamber,

[0056] - placing the chamber cover on the chamber opening of the sample chamber and generating a gas atmosphere in the sample chamber by means of a gas guiding device,

[0057] - piercing a hole in the crucible cover of the sample crucible by means of a piercing device,

[0058] A thermal analysis of the sample is performed with the aid of a temperature control device for regulating the temperature of the sample chamber and a measuring device for measuring the sample temperature and one or more further measured variables.

[0059] The embodiments and special configurations described here for the device according to the invention can be provided in an analogous manner, alone or in any combination, as embodiments or special configurations of the method according to the invention, and vice versa.

[0060] In one embodiment, the chamber cover and the piercing device are structurally combined to form a covering / piercing unit, wherein after piercing the crucible cover and before performing a thermal analysis of the sample, the covering / piercing unit is removed from the chamber opening of the sample chamber and replaced by another chamber cover.

[0061] In a variant of this embodiment, it is provided that the gas atmosphere is generated by a gas flow in the sample chamber by means of a gas guiding device, the flow rate of which is higher during replacement of the covering / piercing unit with another chamber cover than during the thermal analysis.

[0062] In one embodiment of the method, it is provided that the crucible receptacle is designed to be movable in the sample chamber between a first position and a second position, and

[0063] - placing the sample crucible into the sample chamber by storing the sample crucible on a storage surface of the crucible receiving portion when the crucible receiving portion is in the first position,

[0064] - when the crucible receiving portion is in the first position, after placing the chamber cover on the chamber opening of the sample chamber and generating a gas atmosphere in the sample chamber, piercing a hole in the crucible cover,

[0065] After piercing the crucible cover and before thermal analysis of the sample, the crucible receptacle is moved from the first position to the second position.

[0066] Here, the second position of the movable crucible receiving part is preferably arranged further away from the chamber opening and / or closer to the interior of the device than the first position. In particular, the movement of the crucible receiving part can be carried out in the vertical direction, wherein the second position is arranged further away from the chamber opening and / or closer to the interior of the device than the first position (for example, further downward).

[0067] In a variant it is provided that the device has a further chamber cover which can be placed on the chamber opening of the sample chamber instead of on the covering / piercing unit and when the crucible receptacle is in the second position the covering / piercing unit is removed from the chamber opening and replaced by the further chamber cover.

[0068] According to another aspect of the invention, a sample crucible with a crucible cover is proposed, which is designed in a special manner for a device and / or a method of the type described herein and comprises:

[0069] a sample crucible of at least approximately cylindrical design having an inner space for accommodating the sample and a crucible opening,

[0070] a crucible cover which can be placed or placed on the sample crucible at the crucible opening of the sample crucible;

[0071] Wherein, the crucible cover has:

[0072] a cover which can be connected to or to the edge of the opening of the sample crucible, in particular a screw cover in which a cover hole is provided,

[0073] A pierceable sealing layer, which is arranged at the inside of the lid and seals the inner space of the sample crucible.

[0074] Advantageously, for such a sample crucible with a crucible cover, provision is made according to the invention for piercing the hole in the crucible cover so that a needle for this purpose passes through the cover hole and then pierces the sealing layer located underneath.

[0075] The cross sections of the cover hole on the one hand and the needle on the other hand are selected accordingly to be adapted to one another so that the needle or at least one of the needle's tips passes through the cover hole. In one embodiment, the opening surface of the cover hole is at least 2 times larger, in particular 4 times larger, than the maximum cross section of the part of the needle or the needle tip that is located in the region of the cover hole during the puncture process. On the other hand, it is generally advantageous if the opening surface of the cover hole is 10 times larger than the maximum cross-sectional area of ​​the needle (tip).

[0076] The material and thickness of the sealing layer on the one hand and the material and shape of the needle on the other hand should be selected to be adapted to one another so that the material of the sealing layer can be penetrated by the needle and thus a hole can be made in the sealing layer.

[0077] Advantageously, the material and shape design of the cover (in particular, for example, the thickness) can be selected depending on the desired mechanical stability of the cover, regardless of the design of the needle, since during the puncture process the needle passes through the cover in the region of a cover hole, for example, which is designed to be a hole of suitable size through the cover.

[0078] The sample crucible may have a crucible body having at least approximately the shape of a bowl or a pot.

[0079] In one embodiment, the sample crucible is formed from a metal or a metal alloy, such as steel or for example tungsten, titanium or aluminum (or alloys thereof), wherein the surface defining the interior space of the sample crucible can be coated, for example. Precious metals or precious metal alloys, such as gold or gold alloys, are particularly contemplated as materials for such coatings.

[0080] In one embodiment, it is provided that the sample crucible has a circular bottom with a cylindrical or conical jacket which is connected upwardly to the circular bottom in the case of use. The bottom and the jacket can be designed to be connected to each other in one piece, for example. In this case, the crucible opening of the sample crucible is defined by the upper edge of the jacket.

[0081] The maximum lateral extension of the sample crucible may be, for example, in the range of 5 mm to 15 mm and / or the height may be in the range of 5 mm to 15 mm, preferably with a lateral extension / height ratio in the range of 1.0 to 1.5. The wall thickness of the crucible body may be, for example, in the range of 0.5 mm to 1 mm.

[0082] The crucible cover which can be placed at the crucible opening of the sample crucible or is placed on the sample crucible has, as already mentioned, at least one cover and underneath (towards the interior of the sample crucible) a pierceable sealing layer. In one embodiment, the cover is made of a metallic material (metal or metal alloy), for example steel, titanium or aluminum (e.g. of the same material as the sample crucible).

[0083] In one embodiment, it is provided that the cover is designed as a screw cap with a thread (internal or external thread) which can be screwed into a corresponding thread (external or internal thread) of the sample crucible in the region of the crucible opening.

[0084] In one embodiment, the pierceable sealing layer arranged on the inside of the lid and sealing the interior space of the sample crucible is formed as a film of a metallic material. For example, gold or a gold alloy is advantageously considered as a material for the sealing layer. The thickness of the sealing layer can be, for example, in the range of 50 μm to 200 μm.

[0085] To achieve a sealing effect, it can be provided, for example, that the edge of the sealing layer is pressed circumferentially from the cover to the upper edge region of the sample crucible, in other words, is clamped between the cover and the sample crucible.

[0086] In an advantageous variant, it is provided that the crucible cover further comprises a stabilizing layer arranged on the inner side of the sealing layer, the stabilizing layer having a stabilizing layer hole therein which is designed coaxially with the cover hole.

[0087] In this case, for example, it can be provided that the edge of the two-layer structure of the sealing layer and the stabilizing layer arranged below the sealing layer is clamped between the cover and the sample crucible in the circumferential direction to achieve sealing of the interior space of the sample crucible.

[0088] In this variant, the mechanical support of the sealing layer is advantageously formed together with the stabilizing layer so that when a hole is pierced in the crucible cover (piercing the sealing layer), the sealing layer cannot retract under the load of the needle, thus achieving a better defined and reproducible geometry of the piercing.

[0089] The arrangement of the stabilizing layer hole in the stabilizing layer coaxially with the cover hole and thus coaxially with the needle during the puncture process advantageously avoids the puncture movement of the needle being hindered by the stabilizing layer.

[0090] In one embodiment, the opening surface of the stabilizing layer hole is at least 2 times larger, in particular 4 times larger, than the maximum cross section of the part of the needle or needle tip which is located in the region of the stabilizing layer hole during puncture.

[0091] In one embodiment of the device according to the invention, the device comprises at least one sample crucible comprising a crucible cover of the type described herein.

[0092] According to another aspect of the present invention, a covering / piercing unit of an apparatus for thermally analyzing a sample is proposed, wherein the apparatus has a sample chamber for accommodating a sample crucible with a crucible cover placed thereon, the sample to be analyzed is located inside the sample crucible, and wherein the sample chamber has a chamber opening for inserting the sample crucible into the sample chamber, wherein the covering / piercing unit has: a wall arranged for covering the chamber opening; a guide bearing designed on the wall; and a needle movably supported by means of the guide bearing, the needle extending through the wall from an inner side of the wall facing the sample chamber when the covering / piercing unit is placed to an outer side of the wall facing away from the sample chamber when the covering / piercing unit is placed.

[0093] In the case of such a covering / piercing unit according to the invention, in particular special embodiments and designs can be provided, as have already been described here in conjunction with the device according to the invention.

[0094] According to another aspect of the invention, the use of a device of the type described herein and / or a method of the type described herein for performing one or more thermal analyses of a sample is proposed, wherein the thermal analyses are selected from the group consisting of thermogravimetric analysis (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC).

[0095] In one embodiment of the use, a simultaneous thermal analysis is provided which comprises one of the above-mentioned analysis methods and at least one other analysis method.

[0096] In an advantageous more specific embodiment, a use for thermal analysis is provided, which comprises determining the mass of the sample during a temperature program by means of thermogravimetric analysis (TG) and simultaneously determining the type and amount of volatile decomposition products of the sample during the temperature program by means of mass spectrometry (MS or GC-MS).

[0097] In one embodiment of the present invention, the temperature program defines the temperature inside the sample chamber (chamber temperature), for which the method may include, for example, measuring the chamber temperature and driving the temperature control device based on this, preferably using the regulation of the chamber temperature (such as PID regulation) to drive the temperature control device.

[0098] Alternatively, the temperature program can also define a predetermined time course of the sample temperature, for which, for example, a corresponding control (in particular regulation) of the temperature control device can be carried out accordingly based on the measured sample temperature.

[0099] According to the specific implementation of the method or the measuring device used therein, one or more other measured variables of the sample are measured, in particular measured variables such as those related to the characteristics of the sample. For example, when using the method of thermogravimetric analysis (TG), the weight or mass of the sample is measured as a further measured variable during the temperature change or temperature program. Alternatively or additionally, another measured variable may refer to, for example, the type and / or amount of volatile products (e.g. derived by means of gas chromatography and / or mass spectroscopy), and / or may include at least one other temperature and / or temperature difference (e.g. by DSC). Preferably, the method comprises recording measurement data during the temperature program, in particular data representing at least one of the chamber temperature and the sample temperature (preferably both), temperature-dependent and / or time-dependent processes. By evaluating such data, during the temperature regulation and / or after the completion of the temperature program, for example, one or more material parameters of interest of the sample subjected to the process can be derived. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] The present invention will be further described below according to embodiments with reference to the accompanying drawings. The accompanying drawings show:

[0101] Figure 1 shows a cross-sectional view of a device for thermal analysis of a sample according to one embodiment,

[0102] Figure 2 Shows Figure 1 A slightly simplified schematic detail of a cross-sectional view of Figure 1 The covering / piercing unit of the device,

[0103] Figure 3 Shows Figure 2 A cross-sectional perspective view of the covering / piercing unit,

[0104] Figure 4 Shows Figure 2 and Figure 3 A perspective view of the cover part of the covering / piercing unit,

[0105] Figure 5 shows a schematic exploded view of a sample crucible with a crucible cover according to one embodiment,

[0106] Figure 6 Shows Figure 5 A top view of the lid of the crucible cover,

[0107] Figure 7 Shows Figure 5 A top view of the stabilizing layer of the crucible cover, and

[0108] Figure 8 A cross-sectional view of an apparatus for thermally analyzing a sample according to another embodiment is shown. DETAILED DESCRIPTION

[0109] Figure 1 An embodiment of a device 10 for thermal analysis of a sample is shown. The device 10 has a sample chamber 12 for accommodating a sample crucible 14 having a crucible cover 16 placed thereon. The sample to be analyzed is located inside the sample crucible 14 during thermal analysis.

[0110] In the upper region of the device 10 , the sample chamber 12 has a chamber opening 18 , through which a sample crucible 14 can be introduced into the sample chamber 12 in preparation for the analysis.

[0111] The device 10 also has a temperature control device 20, by means of which the sample chamber 12 and thus the sample located in the sample crucible 14 are temperature-controlled during the sample analysis. In the example shown, the temperature control device 20 has a hollow cylindrical heating jacket 22 (eg resistance heating).

[0112] In the exemplary embodiment shown, the device 10 is designed to carry out a method for thermal analysis of a sample, wherein the sample is temperature-regulated according to a predetermined temperature program, during which the chamber temperature inside the sample chamber 12 is changed, wherein during the temperature program with the aid of a measuring device of the device 10 the sample temperature and additionally one or more other measured variables relating to properties of the sample are measured.

[0113] In the exemplary embodiment shown, a thermogravimetric analysis (TG) is provided for the thermal analysis of the sample, wherein (as a further measured variable) the change in the mass of the sample is measured during the temperature program.

[0114] In the embodiment shown, therefore, in addition to the temperature measuring device for measuring the temperature of the sample, the measuring device also comprises a balance 26, by means of which the weight of the sample and the weight of the components for receiving and storing the sample arranged on the balance 26 are measured during the temperature program. In this example, these components include, for example, the sample crucible 14 with the crucible cover 16 and the sample crucible support 28. The temperature-dependent change in the mass of the sample is obtained by evaluating the weight measured by means of the balance 26 during the temperature program.

[0115] In order to generate a defined gas atmosphere or gas flow in the sample chamber 12, the device 10 has a gas guiding device, which in the embodiment shown has in particular a gas inlet 30 arranged in the lower region of the sample chamber 12. In the example shown, a further gas inlet 31 is arranged in the lower region of the sample chamber 12. Via these gas inlets 30, 31, a gas, for example 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.

[0116] In the examples shown and in Figure 1 In the case shown, the gas-conducting device also has a gas outlet 32 ​​arranged in the upper region of the sample chamber 12, in which region of the sample chamber 12 the protective gas can be discharged via the gas outlet 32. In this example, the gas-conducting device of the device 10 also includes a pressure sensor 34 for measuring the pressure in the sample chamber 12 and an overpressure exhaust valve (safety valve) 36, which exhausts gas from the sample chamber 12 in the event of an excessive pressure.

[0117] In order to cover the sample chamber 12 of the device 10 in a gas-tight manner with respect to the atmosphere (ambient air) when performing the thermal analysis, the device 10 also has one or more (optionally) chamber covers which can be placed over the chamber opening 18 of the sample chamber 12. Figure 1 In the case shown, such a chamber cover 40 is placed on the chamber opening 18 .

[0118] A feature of the device 10 is that, in order to reduce the risk of undesired changes in the sample due to chemical or physical reactions with components of the ambient air, the sample crucible 14 can be introduced into the sample chamber 12 in a gas-tightly sealed state by means of the crucible cover 16 and opened there in a gas atmosphere generated by means of a gas guiding device.

[0119] For this purpose, the device 10 also has a piercing device 42, which is equipped with a needle 44 (for example made of steel or another metal alloy), which is designed to pierce a hole in the crucible cover 16 of the sample crucible 14 when the sample chamber 12 is accommodated in the sample crucible 14 and the chamber cover 40 is placed on the chamber opening 18.

[0120] In the example shown, the chamber cover 40 and the piercing device 42 are structurally combined to form a covering / piercing unit 40, 42, and Figure 1 2 shows a situation in which, after the sample crucible 14 has been introduced into the sample chamber 12 through the chamber opening 18 , the covering / piercing unit 40 , 42 is placed onto the chamber opening 18 .

[0121] In this case, the hole may be pierced in the crucible cover 16 of the sample crucible 14 by a needle 44 .

[0122] In the embodiment shown, the covering / piercing unit 40, 42 has a wall 46 for covering the chamber opening 18 and a guide bearing 48 (sliding bearing) formed on the wall 46 for a movable bearing of the needle 44. In this case, the needle 44 extends through the wall 46 from the inner side of the wall 46 facing the sample chamber 12 when the covering / piercing unit 40, 42 is placed to the outer side of the wall 46 facing away from the sample chamber 12 when the covering / piercing unit 40, 42 is placed.

[0123] In the example shown, the “needle drive” provided for the puncture process is achieved by the action of a mechanical force on the portion of the needle 44 located outside the wall 46 .

[0124] For this purpose, the puncture device 42 has a weight 50 that can be guided to move vertically, and the weight 50 can be lowered from a predetermined height relative to the needle 44 to a radial protrusion 52 formed on the shaft of the needle 44 by manual operation of the user, thereby driving the needle 44 downward. Figure 1 The needle 44 is inserted into the crucible and the hole is pierced in the crucible cover 16 by means of the needle tip 54 of the needle 44 .

[0125] In order to predetermine the height at which the weight 50 falls on the radial protrusion 52 of the needle 44, in the example shown, for example, another radial protrusion 56 is formed on the shaft of the needle 44. In the above-mentioned manual operation, the user can first lift the weight 50 guided on the shaft of the needle 44 until the weight 50 reaches the other radial protrusion 56 serving as a stopper, and then release the weight 50. Alternatively or in addition to forming a stopper (protrusion 56) for defining the drop height, for example, one or more marks ("scales") can also be provided on the shaft of the needle 44 so that the weight 50 can be lifted to one or more drop heights defined thereby.

[0126] In the example shown, the piercing device 42 also has a spring device 58, which serves to preload the needle 44 with respect to its piercing direction and is designed in the example shown as a helical compression spring around the axis of the needle 44, which is supported on the one hand on the wall 46 and on the other hand on 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, wherein the extent of this piercing depth ultimately depends on the characteristics of the spring device 58, the drop height and the mass of the weight 50, and the properties of the needle tip (material, geometry) in combination with the properties of the crucible cover 16 to be pierced by it (e.g. the material and thickness of the sealing layer to be pierced).

[0127] In contrast to the exemplary embodiment shown, the puncturing device 42 can also have a mechanical stop, for example, in order to limit the puncturing depth of the needle 44 .

[0128] As is generally advantageous within the scope of the invention, it has been shown that the chamber cover 40 and its wall 46 form a (dome-shaped) "hood component" (see, for example, Figure 4 ), whereby the sample chamber 12 is expanded in a dome-shaped manner in the region of the chamber opening 18 by placing a chamber cover 40 or in the example of the covering / piercing unit 40, 42 shown. In this case, the gas outlet of the chamber cover 40 is preferably arranged in the distal region of the hood shape (in the case of the gas outlet 32 ​​provided in the example shown).

[0129] In the example shown, the piercing device 42 also has a mechanical centering device 60 (“centering aid”), by means of which the sample crucible 14 including the crucible cover 16 is centered relative to the piercing device 42 and thus relative to the needle 44 before the piercing process is performed. Advantageously, the piercing of the crucible cover 16 thus takes place at a well-defined position of the crucible cover 16.

[0130] In the example shown, the centering device 60 of the covering / piercing unit 40, 42 is formed by a plurality of centering claws 62, which are arranged on the inner side of the wall 46 and are designed, for example, integrally with the wall 46, so that when the piercing process is carried out, these centering claws contact the surface of the sample crucible 14 and / or the surface of the crucible cover 16 in order to force the sample crucible 14 and the crucible cover 16 into a specific position (centering) relative to the needle 44 before a hole is pierced in the crucible cover 16 of the sample crucible 14 by means of the needle 44.

[0131] Furthermore, in the example shown, the movable crucible receptacle has the advantage that the sample crucible 14 together with the already pierced crucible cover 16 can be moved from a first position into a second position, before which the covering / piercing unit 40, 42 in the second position is removed from the chamber opening 18 of the sample chamber 12 and replaced by another chamber cover. Since the sample crucible 14 is in the second position further downwards and thus further away from the chamber opening 18, in which a certain gas exchange between the gas atmosphere and the ambient air is unavoidable in practice after the removal of the covering / piercing unit 40, 42, the sample is better protected from contact with the ambient air during this sample preparation phase (changing the chamber cover).

[0132] Figure 2 Shows from Figure 1 The schematic covering / piercing units 40, 42 are enlarged and slightly simplified in the cross-sectional view of FIG.

[0133] Figure 3 A cross-sectional perspective view of the covering / piercing unit 40, 42 is shown.

[0134] Figure 4 Shows Figure 2 and Figure 3A three-dimensional view of the “cover part” of the covering / piercing unit 40, 42, which includes a wall 46 and a centering device 60 formed by a plurality of centering claws 62.

[0135] When performing thermal analysis, in addition to the function of protecting the medium and / or energy (heat) exchange between the sample chamber 12 and the environment, if the chamber cover also has other functions (such as Figure 1 If, after the perforation of the crucible cover 16 and before the thermal analysis of the sample is performed, the covering / piercing units 40, 42 are replaced by a chamber cover that is optimized with respect to the above-mentioned other functions, as shown in the figure, above the covering / piercing units 40, 42, then it is advantageous that after the perforation of the crucible cover 16 and before the thermal analysis of the sample is performed, the covering / piercing units 40, 42 are replaced by a chamber cover that is optimized with respect to the above-mentioned other functions. Such other functions can be, for example, providing a carrier gas outlet, in the case of thermal analysis of the sample, a gas that acts as a carrier gas is transported from the sample chamber 12 to an analysis device (for example, including a mass spectrometer) together with gas components from the sample.

[0136] In the embodiment shown, 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 covering / piercing unit 40, 42 and has a gas outlet similar to the gas outlet 32 ​​of the covering / piercing unit 40, 42, to which a gas line leading to the analysis device can be connected or connected.

[0137] The method of performing thermal analysis of a sample using the apparatus 10 may include in particular the following steps:

[0138] - placing the sample crucible 14 including the crucible cover 16 placed thereon and the sample contained therein into the sample chamber 12 through the chamber opening 18 of the sample chamber 12,

[0139] placing the covering / piercing unit 40 , 42 onto the chamber opening 18 of the sample chamber 12 and generating a gas atmosphere in the sample chamber 12 by means of the gas-conducting devices 30 , 31 , 32 ,

[0140] - perforating a hole in the crucible cover 16 of the sample crucible 14 by means of the perforating device 42 of the covering / perforating unit 40 , 42 ,

[0141] A thermal analysis of the sample is performed with the aid of a temperature control device 20 for temperature control of the sample chamber 12 according to a predetermined temperature program (time-dependent temperature course) and a measuring device for measuring the change in sample temperature and sample mass.

[0142] Here, if the method for thermal analysis of a sample simultaneously provides for a time-dependent determination of the type and amount of volatile decomposition products of the sample during a relevant temperature program by means of mass spectrometry (MS) for thermogravimetric analysis (TG), then, after puncturing a hole in the crucible cover 16, but before carrying out a thermal analysis of the sample, the covering / puncturing unit 40, 42 is removed from the chamber opening 18 of the sample chamber 12 and replaced by the above-mentioned other chamber cover, on which a gas outlet is provided, via which the volatile decomposition products of the sample are conducted to the mass spectrometer during the thermal analysis.

[0143] Here, a gas flow in the sample chamber 12 is induced by means of a gas guiding device, wherein a relevant gas, which can also be called a carrier gas due to its function related to mass spectrometry, flows into the lower region of the sample chamber 12 at the gas inlet 30 and / or 31 at a predetermined flow rate and is discharged into the mass spectrometer in the upper region of the sample chamber 12 at the gas outlet of the chamber cover (if necessary, for example via a separation column of a gas chromatograph).

[0144] In a completely analogous manner, such a gas flow in the sample chamber 12 is already provided in a preliminary actual analysis phase of sample preparation, i.e. when the sample crucible 14 is introduced into the sample chamber 12 and when the covering / piercing unit 40 , 42 is removed from the chamber opening 18 and another chamber cover is subsequently placed on the chamber opening 18 .

[0145] In this case, it is advantageous if the covering / piercing units 40, 42 are as already mentioned with reference to Figure 1 The described has a gas outlet 32, through which the gas flowing into the sample chamber 12 via the gas inlet 30 of the device 10 can flow out of the sample chamber 12 to the environment, for the covering / piercing unit 40, 42 placed on the chamber opening 18. Thus, after placing the covering / piercing unit 40, 42, the air can advantageously be quickly evacuated from the sample chamber 12 and replaced by a gas atmosphere ("inert gas atmosphere"), in which the crucible cover 16 can then be opened (by piercing with the needle 44).

[0146] It is preferably provided here that the gas flow in the sample chamber 12 caused by the gas guiding device is realized in such a way that the flow velocity of the gas flow during the insertion of the sample crucible 14 into the sample chamber 12 and / or during the replacement of the covering / piercing unit 40, 42 by another chamber cover is higher than during the performance of the thermal analysis (for example, at least twice as high).

[0147] Back to Figure 1 ,exist Figure 1 In the embodiment shown in FIG. 1 , the device 10 is composed of a sample crucible support 28 or a sample crucible support 28 disposed on the sample crucible. Figure 1 The crucible receiving portion is formed at the middle and upper end, and the crucible receiving portion has a storage surface for storing the sample crucible 14 thereon, wherein one feature in this example is that the crucible receiving portion can be Figure 1 The device is shown to move in a vertical direction between a first position for storing the sample crucible 14 and for piercing a hole in the crucible cover 16 and a second position (not shown) for performing thermal analysis of the sample.

[0148] In this second position, the sample crucible 14 is located approximately in the center of the heating jacket 22 of the temperature control device 20 in order to perform the thermal analysis. The second position of the movable crucible receptacle or the movable sample crucible support 28 is thus arranged at a position corresponding to the temperature of the sample crucible 14. Figure 1 The first position shown is a lower position, ie, a position further away from the chamber opening 18 and closer to the device 10 .

[0149] In the first position, the introduction and storage of the sample crucible 14 in the device 10 (through the chamber opening of the sample chamber 12 ), for example held with tweezers, is simplified, while in the second position, precise temperature regulation of the sample during thermal analysis can be ensured.

[0150] Furthermore, in the example shown, the movable crucible holder has the advantage that the mechanical loads caused by the puncturing of the crucible cover 16 of the sample crucible 14 are not transmitted to the balance 26, which is provided in this example for thermogravimetric analysis (TG). In a first position, the sample crucible holder 28 is lifted upwards by means of the lifting device 70 and is thus mechanically separated from the balance 26. Only after the puncturing of the crucible cover 16, but before the thermal analysis is performed, the sample crucible holder 28 is lowered downwards by means of the lifting device 70 and is thus stored on the balance 26.

[0151] Furthermore, in the example shown, the movable crucible receptacle has the advantage that the sample crucible 14 together with the already pierced crucible cover 16 can be moved from a first position into a second position, before which the covering / piercing unit 40, 42 in the second position is removed from the chamber opening 18 of the sample chamber 12 and replaced by another chamber cover. Since the sample crucible 14 is in the second position further downwards and thus further away from the chamber opening 18, in which a certain gas exchange between the gas atmosphere and the ambient air is unavoidable in practice after the removal of the covering / piercing unit 40, 42, the sample is better protected from contact with the ambient air during this sample preparation phase (changing the chamber cover).

[0152] Since in the illustrated embodiment a crucible receiving portion (sample crucible support 28) is formed which is movable between a first position and a second position, the method performed with the device 10 can advantageously be arranged.

[0153] - when the crucible receiving portion is in the first position, the sample crucible 14 is placed in the sample chamber 12 by storing the sample crucible 14 on a storage surface of the crucible receiving portion arranged at the upper end of the sample crucible support 28,

[0154] After placing the chamber cover (in the example the covering / piercing unit 40, 42) on the chamber opening 18 of the sample chamber 12 and generating a defined gas atmosphere (preferably a gas flow) in the sample chamber 12, piercing a hole in the crucible cover 16 when the crucible receiving part is in the first position; and

[0155] After piercing a hole in the crucible cover 16 and before performing a thermal analysis on the sample, the crucible receptacle is moved from the first position to the second position.

[0156] In the following description of further embodiments, the same reference numerals are used for components having the same function, each component being supplemented by a small letter to distinguish the embodiment. Here, substantially only the differences of the embodiments already described are discussed, and reference is furthermore explicitly made to the description of the previous embodiments.

[0157] Reference below Figures 5 to 7 An exemplary embodiment of a sample crucible 14a having a crucible cover 16a which can be used particularly advantageously within the scope of the present invention is described.

[0158] Figure 5 A schematic exploded view from the side of a sample crucible 14a with a crucible cover 16a is shown.

[0159] The sample crucible 14 a has a cylindrical shape having an inner space for accommodating a sample and a crucible opening 80 a on an upper end surface of the cylindrical shape.

[0160] In the example shown, the crucible cover 16a consists of a lid 82a, a pierceable sealing layer 84a (sealing membrane) and a stabilizing layer 86a, which can be placed or placed on the sample crucible 14a at the crucible opening 80a of the sample crucible 14a.

[0161] The lid 82a is designed as a screw lid and can be connected circumferentially to the opening edge of the sample crucible 14a at its circumferential region (here: screwable). In this example, the lid 82a has an internal thread at its circumferential edge region, which can be screwed to a corresponding external thread of the sample crucible 14a. In addition, the lid 82a has a centrally arranged lid hole 88a that passes through the lid 82a.

[0162] The pierceable sealing layer 84a is arranged on the inner side of the cover 82a in the installed state of the “sample crucible / crucible cover combination” 14a , 16a and serves in this state to seal the interior of the sample crucible 14a .

[0163] The stabilizing layer 86a is arranged on the inner side of the pierceable sealing layer 84a in the installed state. In addition, the stabilizing layer 86a has a stabilizing layer hole 90a which is arranged coaxially with the cover hole 88a and passes through the stabilizing layer 86a.

[0164] In the mounted state of the sample crucible / crucible cover combination 14a, 16a, the edge of the two-layer structure consisting of the sealing layer 84a and the stabilizing layer 86a arranged therebelow is clamped in the circumferential direction between the cover 82a and the sample crucible 14a.

[0165] In the example shown, the sample container 14a is formed in one piece from steel (bottom and jacket), wherein the surfaces defining the interior space are coated with a gold alloy. In the example shown, the crucible cover 16a consists of steel (lid 82a) and a gold alloy (sealing layer 84a and stabilizing layer 86a).

[0166] In the case of a sample crucible 14a having a crucible cover 16a, it may be advantageous to pierce a hole in the crucible cover 16b so that a needle (eg Figures 1 to 4 The needle 44 in the cover is inserted through the cover hole 88a and then pierces the sealing layer 84a located below the cover hole 88a. In this case, the stabilizing layer 86a is advantageously used to form a mechanical support for the sealing layer 84a, so that when the hole is pierced in the sealing layer 84a, the sealing layer cannot retract under the load of the needle, thereby achieving a well-defined and reproducible geometry of the hole. The arrangement of the stabilizing layer hole 90a advantageously avoids the piercing movement of the needle being hindered by the stabilizing layer 86a.

[0167] Figure 6 A top view of the lid 82a of the crucible cover 16a is shown.

[0168] Figure 7 A top view of the stabilization layer 86a of the crucible cover 16a is shown.

[0169] The diameters of the cover hole 88a and the stabilizing layer hole 90a on the one hand and the size of the needle on the other hand are selected to be adapted to one another so that the needle or at least one tip of the needle passes 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 have the same size and are approximately 0.5 mm.

[0170] Figure 8 Another embodiment of an apparatus 10b for thermal analysis of a sample is shown. Figure 1Like the device 10 described above, the device 10b has a sample chamber 12b for accommodating a sample crucible 14b, on which a crucible cover 16b is placed, wherein the sample to be analyzed is located inside the sample crucible 14b. The sample chamber 12b has a chamber opening 18b in the upper region of the device 10b, through which the sample crucible 14b can be placed in the sample chamber 12b in preparation for analysis. The device 10b also has a temperature control device 20b, by means of which the sample chamber 12b is temperature-controlled according to a predetermined temperature program when analyzing the sample, in which process the chamber temperature inside the sample chamber 12b changes and the sample temperature and one or more other measured variables additionally related to the sample properties are measured by means of a measuring device of the device 10b.

[0171] and Figure 1 Unlike apparatus 10 in FIG. 1 , apparatus 10b is designed to perform thermal analysis of a sample including dynamic differential calorimetry (DSC).

[0172] In this case, two sample crucible holders 28b-1, 28b-2 (equipped with thermocouples for temperature measurement) are provided in the sample chamber 12b, which serve as "sensors", and a sample crucible of the type described can be stored on each of the sample crucible holders. When performing DSC, both sample crucibles are simultaneously or, if necessary, both samples (e.g., "actual sample" and "reference sample") are simultaneously subjected to a common temperature regulation in the sample chamber 12b. Alternatively to the simultaneous temperature regulation of both samples, the second crucible can also be used "empty" during the method, for example (i.e., no sample or reference sample is stored therein).

[0173] The measuring means of the device 10b therefore comprise temperature measuring means for measuring the temperature of both the actual sample (in the sample crucible 14b) and the reference sample (or the "empty" second sample crucible).

[0174] In the case of use of the device 10b, each sample crucible support 28b-1, 28b-2 is used to be able to arrange a sample crucible (for example, the sample crucible 14b described) on each sample crucible support, so that the sample crucible and the sample (including the "reference sample") are arranged in a defined manner in the sample chamber 12b, and for this purpose, the temperature on the lower side of the relevant crucible is measured or the sample temperature is measured (in the case that the crucible 14b contains a sample). For this purpose, a thermocouple (not shown in the figure) is arranged on the surface or in the interior of each sample crucible support 28b-1, 28b-2.

[0175] For the dynamic differential calorimetry performed with the device 10b, in particular, the time-dependent course of the temperature difference measured with the aid of two sensors (sample crucible holder 28b-1, 28b-2) is determined when evaluating the measurement results (measurement data), in particular so that energy effects and / or, for example, temperature-dependent specific heat capacity of the sample can be determined. In a variant (not shown) of the device 10b, for example, a combination of DSC with at least one further thermal analysis method, in particular, for example, TG (thermogravimetric analysis), can be provided.

[0176] With the above-mentioned device 10 ( Figure 1 ), in device 10b ( Figure 8 ), the chamber cover 40b and the puncture device 42b are also structurally combined to form a covering / puncturing unit 40b, 42b, which also has a wall 46b, a guide bearing 48b formed thereon and a needle 44b movably mounted therein.

[0177] With device 10( Figure 1 ) is different, in device 10b ( Figure 8 ), adapted to the "eccentric" position of the crucible cover 16b of the sample crucible 14b to be pierced, the guide bearing 48b and the needle 44b are not arranged in the center of the (eg circular) chamber cover 40b, but are arranged eccentrically.

[0178] In summary, the invention and the described embodiments enable a hermetically sealed sample crucible to be placed in a device for thermal analysis of a sample under protective gas conditions and only opened under protective gas conditions. Advantageously, the risk of changes in the sample due to undesired chemical or physical reactions with components of the ambient air is thus significantly reduced during sample preparation.

Claims

1. A device (10) for thermal analysis of a sample, comprising: - a sample chamber (12) for accommodating a sample crucible (14) having a crucible cover (16) placed thereon, the sample to be analyzed being located inside the sample crucible (14), wherein: The sample chamber (12) has a chamber opening (18) for placing the sample crucible (14) into the sample chamber (12). - a temperature regulating device (20) for regulating the temperature of the sample chamber (12), - a measuring device for measuring the temperature of the sample and one or more other measured variables, - a gas guiding device (30, 31, 32) for generating a gas atmosphere in the sample chamber (12), - a chamber cover (40) which can be placed on the chamber opening (18) of the sample chamber (12), - a piercing device (42) equipped with a needle (44), the piercing device (42) being adapted to pierce a hole in the crucible cover (16) of the sample crucible (14) with the needle (44) when the sample crucible (14) is accommodated in the sample chamber (12) and the chamber cover (40) is placed on the chamber opening (18), wherein the chamber cover (40) and the puncture device (42) are structurally combined to cover the puncture unit, and the device (10) has another chamber cover, and Therein, after puncturing a hole in the crucible cover (16) and before performing a thermal analysis of the sample, the cover puncturing unit is removed from the chamber opening (18) of the sample chamber (12) and replaced by the other chamber cover.

2. The device (10) according to claim 1, wherein: The further chamber cover can be placed on the chamber opening (18) of the sample chamber (12) instead of covering the puncture unit.

3. The device (10) according to claim 1 or 2, wherein: The cover puncture unit has: - a wall (46) arranged to cover the chamber opening (18), - a guide bearing (48) formed on the wall (46) for bearing a movable 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 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 is placed.

4. The device (10) according to claim 1 or 2, wherein: The puncture device (42) has a mechanical stopper, which is used to limit the puncture depth of the needle (44).

5. The device (10) according to claim 1 or 2, wherein: The piercing device (42) has a mechanical centering device (60) for centering the sample crucible (14) including the crucible cover (16) relative to the needle (44).

6. The device (10) according to claim 1 or 2, wherein: A crucible receiving portion having a storage surface is provided in the sample chamber (12) for storing the sample crucible (14) on the storage surface, wherein the crucible receiving portion is movable between a first position for storing the sample crucible (14) and piercing a hole in the crucible cover (16) and a second position for performing a thermal analysis of the sample.

7. A method for thermal analysis of a sample, the sample being located inside a sample crucible (14), the sample crucible (14) having a crucible cover (16) placed thereon, the method comprising the following steps: - placing the sample crucible (14) into the sample chamber (12) through the chamber opening (18) of the sample chamber (12), - placing a chamber cover (40) on the chamber opening (18) of the sample chamber (12) and generating a gas atmosphere in the sample chamber (12) by means of gas-conducting devices (30, 31, 32), - piercing a hole in the crucible cover (16) of the sample crucible (14) by means of a piercing device (42), - performing a thermal analysis of the sample by means of a temperature control device (20) for regulating the temperature of the sample chamber (12) and a measuring device for measuring the sample temperature and one or more other measured variables, The chamber cover (40) and the piercing device (42) are structurally combined to form a covering piercing unit, and after piercing a hole in the crucible cover (16) and before performing a thermal analysis of the sample, the covering piercing unit is removed from the chamber opening (18) of the sample chamber (12) and replaced by another chamber cover.

8. The method according to claim 7, wherein: The gas atmosphere of the sample chamber (12) is generated by a gas flow caused by means of gas guiding devices (30, 31, 32), the flow rate of which is higher during replacement of the cover piercing unit with another chamber cover than during the performance of the thermal analysis.

9. A sample crucible (14a) with a crucible cover (16a), for use in the device (10) according to any one of claims 1 to 6 and / or the method according to any one of claims 7 to 8, the sample crucible (14a) comprising: - a sample crucible (14a) of at least approximately cylindrical design, having an inner space for accommodating the sample and a crucible opening (80a), - a crucible cover (16a) which can be placed or is placed on the sample crucible (14a) at the crucible opening (80a) of the sample crucible (14a), in, The crucible cover (16a) has: - a cover (82a) which can be connected or connected to the opening edge of the sample crucible (14a), the cover (82a) having a cover hole (88a) formed therein, A pierceable sealing layer (84a) which seals the interior of the sample crucible (14a) and is arranged on the inner side of the cover (82a).

10. The sample crucible (14a) with a crucible cover (16a) according to claim 9, wherein: The lid (82a) is a threaded lid.

11. The sample crucible (14a) with a crucible cover (16a) according to claim 9 or 10, wherein: The crucible cover (16a) further comprises: A stabilizing layer (86a) which is arranged on the inner side of the sealing layer (84a) and has a stabilizing layer hole (90a) therein which is designed coaxially with the cover hole (88a).

12. A cover puncture unit of a device (10) for thermal analysis of a sample, wherein: The device (10) comprises a sample chamber (12) for accommodating a sample crucible (14), the sample crucible (14) having a crucible cover (16) placed thereon, the sample to be analyzed being located inside the sample crucible (14), and wherein the sample chamber (12) has a chamber opening (18) for inserting the sample crucible (14) into the sample chamber (12), wherein the cover piercing unit comprises: - a wall (46) arranged to cover the chamber opening (18), - a guide bearing (48) formed on the wall (46), - a needle (44) movable by means of the guide bearing (48), the needle (44) extending from the inner side of the wall (46) facing the sample chamber (12) when the cover piercing unit is placed, through the wall (46) to the outer side of the wall (46) facing away from the sample chamber (12) when the cover piercing unit is placed, Therein, after puncturing a hole in the crucible cover (16) and before performing a thermal analysis of the sample, the cover puncturing unit is removed from the chamber opening (18) of the sample chamber (12) and replaced with another chamber cover.

13. Use of the device according to any one of claims 1 to 6 and / or use of the method according to any one of claims 7 to 8 for performing one or more thermal analyses of a sample, the thermal analyses being selected from the group consisting of thermogravimetric analysis, differential thermal analysis and differential scanning calorimetry.

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