Calibration method for differential scanning calorimeter

Abstract

To provide a calibration method for a differential scanning calorimeter.SOLUTION: A differential scanning calorimeter comprises a temperature-controlled heat source and a sensor arrangement (9). The sensor arrangement (9) comprises sample- and reference-side pan support regions (4r), sample- and reference-side measurement regions, one or more measurement region sensors operative to output a differential heat flow signal (U) representative of the difference in heat flowing across the sample- and reference- side measurement regions (5r) and sample- and reference-side local heater arrangements (3r). A sample pan and a reference pan are arranged on the respective sample and reference-side pan support regions. A volume surrounding the pans is filled with a measuring gas. The method to determine a second calibration factor CE of the differential scanning calorimeter comprises the steps of creating a first steady state of a desired temperature. The method comprises the steps of, once the first steady state is reached, applying heating power to one of the pan support regions (S) by the use of the respective local heater arrangement and determining the second calibration factor based on the ratio of the differential heat flow signal U and the differential heating power.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for calibrating a differential scanning calorimeter, in particular to a method for determining a second calibration factor that allows a given calibration to be adapted to a desired measurement gas and temperature without the need for measurements with reference materials. Furthermore, the present invention relates to a method for determining a conversion factor that can be used together with the second calibration factor to characterize the internal geometry of a differential scanning calorimeter and to calibrate the measurements of the differential scanning calorimeter without or with only limited reference measurements. Finally, the present invention relates to a self-calibrating differential scanning calorimeter that uses at least one of the methods according to the invention.

[0002] A differential scanning calorimeter measures the heat flow to or from a sample in response to the temperature of the sample, allowing phase changes in the sample to be detected and characterized.

[0003] During measurement, the sample is placed in a pan. The pan and the sample inside are in thermal contact with a temperature-controlled heat source, usually a furnace. The pan is typically placed on a pan support area that is part of the sensor device. The volume surrounding the pan is otherwise filled with a measurement gas. The sensor device includes a measurement area and a measurement area sensor that outputs a signal indicative of heat flow through the measurement area.

[0004] The measurement gas is characterized by its chemical nature or by its density or pressure at the temperature of the measurement. The measurement gas may be air at the same pressure as the surroundings, or it may differ from this condition by having a lower or higher pressure or density and / or by having a different chemical nature.

[0005] Calibration is necessary to establish the relationship between the output of the sensor device and the positive or negative heat flow generated by the sample.

[0006] Obviously, part of the heat generated or required by the sample will bypass the path through the pan support area and flow through the measurement gas surrounding the pan. The ratio of the effectiveness of the heat flow paths through the pan support area and through the measurement gas depends to a large extent on the choice of pan and measurement gas, as well as on the sensor device and its mounting, and partly on the temperature of the measurement. Therefore, the calibration should take at least these factors into account. [Background technology]

[0007] In the prior art, differential scanning calorimeters are calibrated using calibration samples: reference substances with known transition characteristics at different temperatures are placed in a pan of the type required for the measurement and measured while surrounded by the measurement gas. The calibration coefficient is determined by comparing the readings of the prior art sensor device with known values ​​of the positive or negative heat flow generated by the sample.

[0008] This method has at least two disadvantages: on the one hand, the temperatures at which calibration measurements can be made are limited to the phase transitions of the reference material; on the other hand, such calibrations are time consuming and need to be repeated for each pan type and measurement gas. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides at least a second calibration factor C E It is possible to overcome these challenges by applying a calibration function using the second calibration factor C E is determined with the aid of an electric heater instead of a reference material. This allows the second calibration factor C to be determined at any temperature and for any measurement gas, without relying on a calibration sample at hand. E Then, this second calibration factor C E can be used to adapt the calibration to the selected measurement conditions. [Means for solving the problem]

[0010] A differential scanning calorimeter includes a temperature controlled heat source and a sensor device. The sensor device includes a pan support area on the sample side and a pan support area on the reference side, a measurement area on the sample side and a measurement area on the reference side, and a local heater device on the sample side and a local heater device on the reference side. The local heater device is preferably an electric heater device. The temperature controlled heat source is preferably a furnace.

[0011] The sample-side pan support area is adapted to receive in thermally conductive contact the bottom area of ​​the sample pan. The pan support area of ​​the reference side is adapted to receive in thermally conductive contact the bottom area of ​​the reference pan. The measurement area on the sample side surrounds the pan support area on the sample side, and the measurement area on the reference side surrounds the pan support area on the reference side.

[0012] In one embodiment, the sample-side measurement area sensor and the reference-side measurement area sensor are operable to output a differential heat flow signal (U) representative of the difference between heat flowing across the measurement area on the sample side and heat flowing across the measurement area on the reference side.

[0013] In one embodiment, the sample-side measurement area sensor and the reference-side measurement area sensor generate a sample-side heat flow signal (U S ) and the reference heat flow signal (U R ).

[0014] A sample-side local heater device is adapted to apply heating power to a sample-side pan support area. A local heater device on the reference side is adapted to apply heating power to a pan support area on the reference side.

[0015] A sample pan of a desired pan type is placed on the pan support area on the sample side and a reference pan of the same desired pan type is placed on the pan support area on the reference side. The volume surrounding the sample pan and reference pan is filled with the desired measurement gas.

[0016] Second calibration factor C using a differential scanning calorimeter E The method for determining Creating a first steady state of a desired temperature by using a heat source; once the first steady state is reached, applying heating power to either the sample side pan support area or the reference side pan support area by using the respective local heater device so as to reach a second steady state; Differential heat flow signal U and Differential heating power, determining a second calibration factor based on the ratio of Includes.

[0017] The differential heat flow signal U is the direct output of the sample-side and reference-side measurement area sensors in one embodiment of the differential scanning calorimeter. In this embodiment, the differential heat flow signal U is measured directly. In other embodiments of the differential scanning calorimeter, the differential heat flow signal U is the direct output of the sample-side heat flow signal U. S and the reference heat flow signal U R So, the difference between the two values ​​is: U=U S -U R is determined as:

[0018] The differential heating power is the difference between the heating power applied to the sample side and the heating power applied to the reference side during the second steady state.

[0019] Preferably, the sample-side measurement area and the reference-side measurement area include sample-side and reference-side measurement area sensors in the form of thermoelectric devices operable to output a differential thermoelectric voltage signal as a differential heat flow signal (U) representative of the difference between heat flowing across the sample-side measurement area and heat flowing across the reference-side measurement area.

[0020] Preferably, the sample-side measurement area includes a sample-side measurement area sensor in the form of a thermoelectric device and the reference-side measurement area includes a reference-side measurement area sensor in the form of a thermoelectric device. The thermoelectric device generates a sample-side heat flow signal (U S) as the thermoelectric voltage signal on the sample side, and the heat flow signal on the reference side (U R ) as a reference-side thermoelectric voltage signal.

[0021] In one embodiment, the sample-side and reference-side measurement area sensors are realized by a thermoelectric device that compares the temperature of the sample-side pan support area with the temperature of the reference-side pan support area. This is preferably done by a thermoelectric device in which an electrical junction between wires of a first and second metal is located directly beneath the sample-side pan support area and the reference-side pan support area. The thermoelectric device is operable to output a differential thermoelectric voltage signal as a differential heat flow signal (U) representative of the difference between the heat flowing across the sample-side measurement area and the heat flowing across the reference-side measurement area.

[0022] In one embodiment, the sample-side measurement area sensor is a thermometer, preferably a thermoelectric device, that measures the temperature of the sample-side pan support area. The reference-side measurement area sensor in this embodiment is also a thermometer, preferably a thermoelectric device, that measures the temperature of the reference-side pan support area. The thermometer measures a sample-side heat flow signal (U S ), and the reference heat flow signal (U R ).

[0023] The sensor device can be realized as a single detection unit or as a collection of detection units. If the sensor device is realized as a collection of detection units, the sensor device preferably comprises a first detection unit and a second detection unit. Thereby, the first detection unit preferably comprises parts related to the sample side, while the second detection unit comprises parts related to the reference side. In another embodiment of the sensor device realized as a collection of detection units, the local heater is arranged on the first detection unit, while the pan support area and the measurement area are arranged on the second detection unit. The measurement area sensor can be included in the first or second detection unit or belong to a third detection unit.

[0024] The first steady state is preferably determined by a second calibration factor C E determines the temperature at which During the second steady state, at least one of the local heater devices is turned on and supplies a known amount of heat to the system. The heat generated by the local heater devices flows partially through a measurement area surrounding the respective local heater device and partially to a pan located on the pan support area to which the respective local heater device can provide its heat. The heat flow through the measurement area generates sample-side and reference-side heat flow signals or differential heat flow signals.

[0025] Therefore, the ratio of the measured differential heat flow signal to the known heat flow generated by the local heater is: Heat flow resistance through the measurement area relative to the total heat flow resistance, or The heat flow resistance through the contact between the pan and the pan support and through the measurement gas, relative to the total heat flow resistance, Includes information about.

[0026] This situation can be described by the model shown and explained with reference to FIG. In one embodiment, the second calibration factor is: U = differential heat flow signal, P el can be written as follows, where is the differential heating power:

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[0027] Subsequent measurements can be calibrated using this result as follows.

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[0028] Here, P S is the heat flow to or from the sample, U is the differential heat flow signal, P elis the differential heating power detected during the measurement of the sample. F is a conversion factor that depends on the geometry of the measurement and can be provided to the user, for example in the form of a table. Further options for deriving a suitable value for the conversion factor F are described below. C E is the second calibration factor, which was determined with the method according to the invention using a local heater of the sensor device.

[0029] This calibration can be used for measurement modes with and without a local heater. In this latter case the differential heating power is zero: el =0.

[0030] In a preferred embodiment, the local heater devices on the sample side and the reference side are realized as electric heater devices, in which the heating power applied to the sample side and the reference side, respectively, is determined by measuring the voltage and current between the two terminals of each electric heater device.

[0031] Preferably, the electrical resistance R of each electric heater device S , R R R is evaluated to be the ratio of the measured voltage to the measured current, and this value is stored along with the first steady-state temperature. S is the electrical resistance of the electric heater device on the sample side. R R is the electrical resistance of the electric heater device on the reference side.

[0032] Because heaters age over time, measuring both voltage and current simultaneously to determine electrical resistance improves accuracy compared to alternative solutions where the calibration method involves measuring either voltage or current and uses a given resistance value to determine heating power. Storing the electrical resistance value is useful for detecting aging effects, damage, and asymmetries between the reference and sample sides.

[0033] The self-calibrating differential scanning calorimeter according to the present invention calculates the second calibration coefficient C according to the above-mentioned method. EThe self-calibrating differential scanning calorimeter comprises, in addition to the features of a differential scanning calorimeter suitable for use in this method, a data evaluation unit.

[0034] The data evaluation unit can receive the differential heat flow signal and / or the heat flow signals on the sample side and the reference side as well as the differential heating power and / or a signal indicative of the heating power applied to the sample side and the reference side, respectively. In a preferred embodiment, the data evaluation unit can receive the voltage and current between the respective terminals of both electric heater devices as signals indicative of the heating power applied to the sample side and the reference side, respectively.

[0035] The data evaluation unit further includes a memory having a set of instructions, the set of instructions including: E The method includes instructions for performing the method for determining

[0036] Preferably, the set of instructions further comprises: E Particularly preferably, the determined second calibration factor C E is stored with data describing the pan type, the measurement gas, and the first or second steady state desired temperature as each instruction is executed.

[0037] The type of bread is usually determined by the material and size of the bread. Bread types can also differ in their shape and further characteristics.

[0038] Preferably, the data evaluation unit calculates a second calibration coefficient C E and (b) adapted to evaluate the heat flow to or from the sample in the sample pan based on a differential heat flow signal, and / or sample and reference side heat flow signals, and / or signals indicative of the heating power applied to the sample and reference sides, respectively, in combination with the differential heat flow signal.

[0039] In a further embodiment, the data evaluation unit is equipped to access or receive a conversion factor F which depends on the type of pan and preferably on the first or second steady state temperature.

[0040] Preferably, the data evaluation unit determines the conversion factor F and / or the second calibration factor C based on the differential heat flow signal and / or the heat flow signals on the sample side and the reference side and / or the signals indicative of the heating powers applied to the sample side and the reference side, respectively. E In combination with the sample pan, the apparatus is equipped to evaluate the heat flow to or from the sample in the sample pan.

[0041] A self-calibrating differential scanning calorimeter has access to the uncalibrated raw data and can allow the user to take advantage of the second calibration coefficients without having to calculate them themselves or on an external computer.

[0042] In most cases, C. E changes only slowly over time and depends in most cases on the choice of pan type, measurement gas, and temperature. Therefore, the determined C E Storing the values ​​makes it possible to reduce the number of calibration measurements and therefore the total calibration time. If the stored data also contains information about the pan type, the measurement gas, and the temperature, the user can easily store the stored second calibration factor C for the desired measurement conditions, even if the measurement conditions have changed since the last measurement. E The user can select and / or instruct the self-calibrating DSC to access and use the C. The measurement conditions, in this case, include pan type, measurement gas, and temperature. The user and / or instructions stored in the memory of the self-calibrating DSC can specify a tolerance in the measurement conditions. The tolerance is the degree to which the desired measurement conditions are within the C. E The stored C values ​​may vary within the range specified by the measurement conditions and intervals at which they were determined. EThe values ​​are intervals deemed appropriate to use for the desired measurement conditions.

[0043] A conversion factor F can be introduced to describe the dependence of the adjustment on the type of pan. The factor F can be chosen to be independent of the individual sensor device itself.

[0044] This allows the user to be provided with a set of values ​​of the conversion factor F for the types of bread available, or to be provided with the conversion factor F together with the bread it relates to. The conversion factor F can be used with different sensor devices of the same type, and with different differential scanning calorimeters of the same type and shape.

[0045] A data evaluation unit having access to or able to receive the conversion factor F for the desired pan type can further reduce the need for calibration measurements. At least in measurement modes where the heat flow generated by the sample is balanced by the heat flow generated by the local heater device such that there is no differential heat flow signal U, only the conversion factor F is needed to evaluate the desired value of the heat flow to or from the sample.

[0046] The evaluation of the desired heat flow due to the sample is described in detail with reference to FIG. The second calibration factor C E can be determined by the method according to the invention before the measurement is started and the conversion factor F can be provided to the user, so that the heat flow to the sample is preferably calculated by a second calibration factor C E and a conversion factor F.

[0047] In a preferred embodiment of the self-calibrating differential scanning calorimeter, the data evaluation unit determines a first default calibration coefficient C that depends on the type of pan, the measurement gas, and the temperature. Hd can be accessed.

[0048] The data evaluation unit of this preferred embodiment of the self-calibrating differential scanning calorimeter preferably further comprises a data evaluation unit for evaluating the heat flow to or from the sample in the sample pan, either directly or by measuring the difference U=U between the heat flow signal on the sample side and the heat flow signal on the reference side. S -U R The differential heat flow signal is determined to be either 0.01 or 1.001 and a first default calibration factor.

[0049] In formula form, this evaluation is P S =U / C Hd Here, P S indicates the heat flow to or from the sample in the sample pan.

[0050] During this measurement, neither the sample side local heater device nor the reference side local heater device applies heating power to the pan support areas on the sample side and reference side, respectively.

[0051] This allows the user to perform measurements even if there is no time to perform a proper calibration. Moreover, it offers the user the possibility to cross-check the measurements if he has the impression that the determination of the second calibration factor has returned an incorrect result, which may be due to, for example, technical problems with the local heater device or a typo in the calculations.

[0052] Preferably, the first default calibration factor C Hd is the differential heat flow measured as a differential heat flow signal (U) in the absence of any localized heating, multiplied by the known heat flow P generated by a reference material. S is a first calibration factor determined by comparing

[0053] Preferably, a first default calibration factor C at the desired measurement conditions Hd is the differential heat flow measured under different measurement conditions, without any local heating, as a differential heat flow signal (U), compared to the known heat flow P generated by the reference material. S by interpolation and / or extrapolation using a first set of calibration coefficients determined by comparing

[0054] The method for determining the conversion factor F can be applied to a common differential scanning calorimeter. However, it is more comfortable for the user to carry out the method using a self-calibrating differential scanning calorimeter according to the invention.

[0055] A first embodiment of a method for determining the conversion factor F using a differential scanning calorimeter comprises the following steps, preferably carried out using a self-calibrating differential scanning calorimeter: The second calibration factor C E at a first desired temperature, the pan containing a calibration sample known to undergo an exothermic or endothermic transition at a transition temperature different from the first desired temperature. Controlling the heat source such that the transition temperature is reached and the transition of the sample occurs while no heat is being applied by the sample side local heater arrangement or the reference side local heater arrangement. integrating the differential heat flow signal U during the transition of the calibration sample and comparing this result with the theoretical enthalpy of transition of the calibration sample, this comparison being preferably performed by calculating a ratio, a first calibration coefficient C H The step is saved as. The ratio of the first calibration factor to the second calibration factor (C H / C E ) as a conversion factor F, preferably together with the type of pan used for this measurement.

[0056] The differential heat flow signal U can be measured directly or calculated as the difference U between the measured heat flow signal on the sample side and the measured heat flow signal on the reference side, U = U S -U R It can also be determined by calculating

[0057] As explained above, the second calibration factor C E uses a known heat flow generated by a local heater device that heats the pan support area for calibration and determines a first calibration coefficient C Huses the known transition of a calibration sample in the pan, which is placed in the pan support area for calibration. By combining both calibration coefficients, a conversion factor F can be determined that characterizes the thermal resistance between the pan and its surroundings.

[0058] In a further embodiment, the first desired temperature is equal to the transition temperature and C E is determined by using a local heater device on the reference side and a reference pan after a transition of a calibration sample placed in a sample pan on the sample side occurs. In particular, if the heating power applied to the pan support area on the reference side is similar to the heating power generated by the sample during its transition, this allows the first and second calibration factors C E and C H As well as the coefficient F can be determined at even more similar temperatures.

[0059] A second embodiment of the method for determining the conversion factor F by means of a common differential scanning calorimeter, preferably a self-calibrating differential scanning calorimeter, comprises the following steps: The second calibration factor C E performing the method of determining at a third temperature; A first default calibration factor C for the pan type, the measurement gas, and preferably a third temperature Hd accessing the The ratio between the first default calibration factor and the second calibration factor (C Hd / C E ) as a conversion factor F, preferably together with the type of pan used for this measurement; Includes. The steps of this method are preferably carried out in a self-calibrating differential scanning calorimeter.

[0060] This allows the conversion factor F to be determined without a calibration sample. This method can be used when measurements are to be made on a bread type for which there is no F value available. When this method is used with a general differential scanning calorimeter, the step of accessing the first default calibration factor may involve database access, or the use of an external computer program by the user.

[0061] A third embodiment of the method for determining the conversion factor F of a type of pan placed in a given oven in the pan support area on the sample side, used by a differential scanning calorimeter using a type of pan, a given oven as a temperature-controlled heat source, and a pan support area on the sample side, is: The geometric coefficient g, which is the thermal resistance between the pan of a given pan type placed in the pan support area on the sample side and the furnace, assuming the thermal conductivity of the gas to be 1 L preferably by computer simulation; Geometric coefficient g L and estimating a value of a conversion factor F based on the radius r of the base of said type of bread; Includes.

[0062] Preferably, this method is used to determine the conversion factor F of a self-calibrating differential scanning calorimeter using this pan type, a furnace as the temperature controlled heat source, and a sample-side pan support area.

[0063] Preferably, the height d of the area between the pan and the pan support area is also used to estimate the value of the conversion factor F according to this embodiment. Preferably, the thermal resistance R between the pan and the oven L is calculated by the measurement gas having thermal conductivity λ,

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[0064] The thermal resistance between the pan and the pan support area is also determined by the measurement gas and can be approximated as a pan base of radius r and a cylinder with height d, usually a few microns, preferably between 10 and 30 μm, most preferably between 15 and 17.5 μm.

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[0065] The conversion factor F is the ratio C of the first calibration factor to the second calibration factor H / C E The first calibration factor C H is determined with a known heat source or sink inside the pan. The second calibration factor, C E is determined with a known heat source heating the pan support area beneath the pan. As explained below, according to the model in Figure 2, F represents the ratio of thermal resistances.

[0066]

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[0067] Therefore, the effective thickness of the measurement gas between the pan and the furnace (effectively g L ) to determine the conversion factor F. L To determine , the thermal resistance can be calculated, for example, by computer simulation, assuming a thermal conductivity λ = 1 in the units used in the calculation. It is also possible to carry out such simulations for a different value of thermal conductivity and divide the results by this value.

[0068] This method allows a user to estimate the calibration of a pan with an unknown coefficient F without having to measure it.

[0069] Such an estimate of the conversion factor F is calculated using the second calibration factor C determined by the method described above. E This eliminates the need for a calibration sample altogether. Preferably, this third embodiment is used to provide F-values ​​for pans for which there are no suitable values ​​derived with the aid of a calibration sample.

[0070] A method for assessing heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrating differential scanning calorimeter, preferably comprises the following steps. Placing a sample in a sample pan of a pan type, placing the sample pan in the pan support area on the sample side, and placing an empty reference pan of the same pan type in the pan support area on the reference side. Controlling a temperature controlled heat source to follow a desired temperature program. Measuring or determining a differential heat flow signal while no heat is being applied by the local heater arrangement on the sample side or the reference side. Differential heat flow signal U, conversion factor F, and second calibration factor C E estimating the heat flow to or from the sample using a conversion factor F selected according to the type of pan and a second calibration factor C E is selected depending on the type of pan, the measurement gas, and the temperature of the measurement, step.

[0071] Preferably, the chemistry and / or conditions of the measurement gas in the volume surrounding the sample and reference pans are adapted to desired values.

[0072] In this case, the estimated heat flow is

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[0073] This heat flow estimate is calculated using a second calibration factor, CE uses a local heater device and the conversion factor F can be derived from tables, other data sources, or computer simulations and / or theoretical calculations, so it can be derived with high accuracy without the need for calibration samples.

[0074] In a preferred embodiment of the method for evaluating the heat flow to or from a sample in a sample pan using a differential scanning calorimeter, a second calibration coefficient C E According to the present invention, E Between the determination of and the evaluation of the heat flow to or from the sample, a second calibration factor C can be calculated without removing the sample or reference pan. E is determined using the method for determining

[0075] This is because the contact between the pan support area and the pan located on it is the second calibration factor C used in the calibration. E This has the advantage that the determination and measurement of θ are the same, which improves the quality of the calibration.

[0076] A further method for evaluating the heat flow to or from a sample in a sample pan uses a differential scanning calorimeter, preferably a self-calibrating differential scanning calorimeter. The method includes an evaluation step, at least one calibration step, and a measurement step. The at least one calibration step and the measurement step are both performed using the same pan type and the same measurement gas. The calibration step includes the following steps.

[0077] Placing a sample pan containing a calibration sample in the sample pan support area and placing an empty reference pan of the same type in the reference pan support area. The calibration sample is known to undergo an exothermic or endothermic transition at a transition temperature. Controlling the heat source such that the transition temperature is reached and the transition of the calibration sample occurs while no heat is being applied by the local heater device on the sample side or the reference side. integrating the differential heat flow signal U during the transition of the calibration sample and comparing this result with the theoretical enthalpy of transition of the calibration sample, this comparison preferably being performed using a first calibration coefficient C H The step is saved as. The measurement step includes the following steps.

[0078] Placing a sample pan containing a sample of the substance of interest in the pan support area on the sample side and placing an empty reference pan of the same type in the pan support area on the reference side. Controlling the temperature controlled heat source to follow a desired temperature program while no heat is being applied by the local heater devices on the sample or reference side. Observing the differential heat flow signal.

[0079] The evaluation step includes the following steps: A differential heat flow signal and preferably a first calibration coefficient C H and estimating the heat flow to or from the sample of the target material from the comparison result of the calibration step, which is stored as

[0080] Preferably there are several calibration steps, where each calibration step is carried out at a different transition temperature, the transition temperatures preferably being selected to be within the temperature range covered by the temperature program of the measurement step.

[0081] Preferably, the chemistry and / or conditions of the measurement gas in the volume surrounding the sample and reference pans are adapted to desired values.

[0082] Preferably, this embodiment of the method for estimating the heat flow further comprises a second calibration factor C E The method for determining C H Preferably, the ratio C at different temperatures is determined by a further calibration step performed at a temperature equal to the transition temperature used to determine H / C E The F values ​​obtained from the calculation of are added to a memory accessible to the data evaluation unit.

[0083] A further method for assessing heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrating differential scanning calorimeter, comprises the following steps. Placing a sample in a sample pan of a pan type, placing the sample pan in the pan support area on the sample side, and placing an empty reference pan of the same pan type in the pan support area on the reference side. Controlling a temperature controlled heat source to follow a desired temperature program. Controlling the local heater devices on the sample side and the reference side so that the absolute value of the differential heat flow signal is minimized. A differential heating power P as well as a differential heat flow signal U, preferably from the heating power of local heater devices on the sample and reference sides el Measuring or determining. ·Differential heat flow signal U, differential heating power P el , a conversion factor F, and a second calibration factor C E estimating the heat flow to or from the sample using a conversion factor F and a second calibration factor C E is selected depending on the type of pan, the measurement gas, and the temperature of the measurement, step.

[0084] Preferably, the chemistry and / or conditions of the measurement gas in the volume surrounding the sample and reference pans are adapted to desired values.

[0085] As explained with reference to FIG. 2, the heat flow to or from the sample is determined by a second calibration factor C E and the value of the conversion coefficient F, the measured values ​​U and P el It can be calculated from the following:

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[0086] In this case, the differential heat flow signal U is minimized. In the ideal case, this would result in U=0 and only the conversion factor F is needed to derive the result. However, when the control is slowed down, an associated differential heat flow signal U arises, so that a second calibration factor C is needed in the evaluation of the result. E may need to be considered.

[0087] As explained above, the conversion factor F is a geometric property of the measurement setup and is independent of the sensor device used for the in situ measurement, therefore the heat flow determined by this method is much more independent of the instrument with which it is determined.

[0088] Differential heating power P el can have a positive or negative value. If the sample generates heat, heat is generated on the sample side and the local heater device on the reference side is controlled to compensate for it. On the other hand, if the sample needs heat for a transition, the local heater device on the sample side is controlled to start generating heat to compensate for this heat sink.

[0089] In a preferred embodiment of the further method for evaluating the heat flow, the differential heating power P el is set to minimize the absolute value of the differential heat flow signal U by the gain k p The pressure sensor is controlled by a proportional controller having a

[0090] Differential heating power P el is the value obtained by subtracting the value on the reference side from the value on the sample side, i.e., P el =P el,S -P el,r and U is the differential heat flow signal, the proportional controller is

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[0091] Preferably, the gain is determined by a gain constant k and a default first calibration factor C Hd The value of the gain constant k is selected depending on the desired time resolution of the measurement, and the default first calibration factor C Hd The value of is selected depending on the temperature, pan type, and measurement gas.

[0092] Such a selected gain allows the user to work with the same desired time resolution under different measurement conditions, e.g. temperature, pan type and measurement gas.

[0093] Particularly preferably, the heating power of the local heater devices on the sample side and on the reference side is controlled by controlling the voltage and / or current supplied to the local heater devices in the form of electric heater devices. Thereby, the second calibration factor C E The electrical resistance R of the electric heater device is determined by a preferred embodiment of the method for determining S , R R is taken into consideration.

[0094] This method allows the electrical resistance at different temperatures to be determined, so that the results can be used to calculate the desired differential heating power (P el These are particularly useful for determining the voltage or current required to achieve a given voltage.

[0095] In a preferred embodiment of the further method for evaluating the heat flow to or from a sample in a sample pan, a second calibration factor C E is C EBetween the determination of and the evaluation of the heat flow to or from the sample in the sample pan, a second calibration factor C can be calculated without removing the sample or reference pan. E is determined by the method for determining

[0096] If the local heating devices are electrical heating devices, their electrical resistance R S , R R is preferably a second calibration coefficient C E This is determined during the determination of the

[0097] By using this embodiment, the actual placement of the pans can be taken into account which can improve the results.

[0098] A further embodiment of a method for evaluating heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrating differential scanning calorimeter, comprises at least one calibration step and a measurement step, the at least one calibration step and the measurement step both being performed using the same pan type and the same measurement gas, and the evaluation step being performed after the calibration step and the measurement step.

[0099] The calibration step includes the following steps. Placing a sample pan containing a calibration sample in the pan support area on the sample side. The calibration sample is known to undergo an exothermic or endothermic transition at a transition temperature. Placing an empty reference pan of the same type in the pan support area on the reference side. Preferably, a second calibration factor C E or by determining a second calibration factor C for a given condition E The second default calibration factor, C, is created by accessing the previously stored value of Ed A step of determining: Controlling the heat source such that the transition temperature is achieved and transition of the calibration sample occurs while the electric heater is controlled to minimize the differential heat flow signal. During the sample transition, the differential heating power P of the local heater devices on the sample and reference sides as well as the differential heat flow signal U areel Measuring or determining. Over time, the transition of the sample Differential heat flow signal U and ○ Second default calibration factor C Ed and the differential heating power P el The product of Difference between (UP el C Ed ) step. comparing this integral value with the theoretical enthalpy of transition of the calibration sample, this comparison value being preferably a default second calibration coefficient C used in the integration; Ed together with the first calibration factor C H The step is saved as. Preferably, the comparison between the integral of the difference between the differential heat flow signal and the product of the second default calibration factor and the differential heating power and the theoretical enthalpy of transition of the calibration sample is performed by a mathematical operation such as calculating their quotient.

[0100] The measurement step includes the following steps. Placing a sample pan containing a sample of the substance of interest in the pan support area on the sample side and placing an empty reference pan of the same pan type in the pan support area on the reference side. Controlling a temperature controlled heat source to follow a desired temperature program. Controlling the local heater devices on the sample side and the reference side so that the absolute value of the differential heat flow signal is minimized. The differential heat flow signal U as well as the differential heating power P el Measuring or determining.

[0101] The evaluation step includes the following steps: ·Differential heating power P el , differential heat flow signal U, default second calibration factor C Ed , and the comparison result of the calibration step, preferably a first calibration coefficient C H estimating the heat flow to or from the sample using

[0102] In this case, the heat flow to and from the sample in the sample pan can be calculated as follows:

number

[0103] In a preferred embodiment, in a method for evaluating the heat flow to or from a sample in a sample pan of a certain pan type surrounded by a measurement gas, a conversion factor F is selected depending on said pan type and the temperature of a preferably temperature-controlled heat source. The measurement gas and its properties are preferably determined by a second calibration factor C determined at the temperature of the pan of said pan type, the measurement gas and the preferably temperature-controlled heat source. E This is taken into account by selecting

[0104] The choice of the measurement gas and its properties such as density or pressure determine its thermal conductivity. As can be seen in the description of the theoretical method for determining F, the thermal conductivity of a gas is determined by both terms: the thermal resistance R between the sample support area and the pan k , and the thermal resistance between the pan and the temperature-controlled heat source R L Since F only represents the ratio of these two resistances, the thermal conductivity of the measurement gas cancels out, and F is independent of the measurement gas at hand, as long as thermal conductivity is the dominant heat transfer process in the measurement gas.

[0105] C E The method of determining F is very fast, does not require specific samples, and selects F depending on the type of pan and preferably the temperature, while C E Since the effect of the measurement gas can be taken into account, no additional sensors or additional user input is required to determine the measurement gas and its conditions. The measurement is simply a C E The process can begin with the determination of:

[0106] In a preferred embodiment of the self-calibrating differential scanning calorimeter, the sensor devices are located in a volume surrounded by the same temperature controlled heat source. Preferably, a single detection unit contains the sensor devices.

[0107] Such a self-calibrating differential scanning calorimeter has a second calibration coefficient C E This arrangement makes it particularly easy to ensure symmetry between the sample side and the reference side.

[0108] In another embodiment, the pan support area on the sample side, the measurement area on the sample side, and the local heater device on the sample side are part of a first detection unit. The pan support area on the reference side, the measurement area on the reference side, and the local heater device on the reference side are part of a second detection unit. The sensor device includes, in this embodiment, a first and a second detection unit.

[0109] In a preferred embodiment, the first and second detection units of this embodiment are located in a volume surrounded by the same temperature controlled heat source.

[0110] In another preferred embodiment, the first detection unit is disposed in a first volume surrounded by a first temperature-controlled heat source and the second detection unit is disposed in a second volume surrounded by a second temperature-controlled heat source. The first temperature-controlled heat source and the second temperature-controlled heat source are preferably connected such that their temperatures are the same.

[0111] In a preferred embodiment of the self-calibrating differential scanning calorimeter, the single, first and / or second detection units are positioned to contact the temperature-controlled heat source on a surface opposite the pan support area. This arrangement ensures thermal contact between the temperature-controlled heat source and the respective detection unit, while allowing the detection units to be replaced without modifying the temperature-controlled heat source.

[0112] In another preferred embodiment, the single, first and / or second detection unit is positioned such that its edge is in contact with the temperature-controlled heat source, while the surface opposite the pan support area is exposed to a volume surrounded by the temperature-controlled heat source. [Brief description of the drawings]

[0113] [Figure 1] FIG. 1 is a highly schematic diagram of a self-calibrating differential scanning calorimeter. [Diagram 2] FIG. 2 is a diagram of a corresponding thermal circuit model. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0114] The diagram of Figure 1 is a highly schematic partial cross-sectional view of a self-calibrating differential scanning calorimeter in a plane extending perpendicular to the horizontally extending pan support area 4r. F A furnace 1 is shown forming a heat source controlled according to a given temperature program and appears as a rectangle enclosing a volume surrounding the sensor arrangement. The sensor arrangement comprises a sample side S and a reference side R which differs only by the presence of a sample 7 in a pan 2s of the sample side S. The self-calibrating differential scanning calorimeter further comprises a data evaluation unit 10.

[0115] To avoid overcrowding the figure, most of the reference numbers are shown only on the reference side of the sensor device, although the respective structures are also present on the sample side. Similarly, although the heat flows are shown on the sample side, they apply to the reference side as well.

[0116] The sensor apparatus 9 includes sample-side and reference-side pan support areas 4r, the measurement areas on the sample side and reference side including thermoelectric devices operable to output at least one thermoelectric voltage signal representative of heat flow 6m across a measurement area 5r surrounding the respective pan support area 4r. The sensor apparatus 9 further includes sample-side and reference-side local heater devices in the form of electric heater devices 3r.

[0117] Pans 2s, 2r adapted to receive samples 7 of the substance to be analysed are supported by a thermally conductive pan support area 4r which is part of the sensor device 9. The sensor device 9 is in thermal contact with the furnace 1. The measurement area 5r is arranged such that mechanical contact between the furnace 1 and the sensor device 9 is established only by one end of the measurement area 5r, the other end of the measurement area 5r being an area in thermal contact with the electric heater device 3r and the pan support area 4r.

[0118] The thermally conductive member formed by the measurement area 5r thereby establishes a heat flow path 6m between the oven 1 and the pan support area 4r, which will be referred to below as the measurement heat flow path 6m, the characteristic of which is indicated by the subscript "m".

[0119] The circles drawn in the measurement area 5 symbolize thermoelectric junctions located in the swirl area of ​​the thermoelectric device that meanders around the pan position. With this configuration, the thermoelectric device generates a thermoelectric voltage signal representative of the measured heat flow 6m flowing across it. This thermoelectric voltage signal is one embodiment of a heat flow signal. The thermoelectric device is one embodiment of a measurement area sensor.

[0120] An electric heater device 3r is arranged below the respective pan support area 4r. Straight arrows symbolize the heat flow from the area of ​​the electric heater device 3r towards the respective pan 2r, 2s. This heat flow path 6k is referred to below as contact heat flow path 6k and its characteristic is indicated by the subscript "k".

[0121] Besides the measurement heat flow 6m and the contact heat flow 6k, each pan 2s, 2r is in thermal contact with the oven 1 via a sensor device 9 and a measurement gas 8 filling the volume between the pan 2 and the oven 1. This heat flow path 6l is also indicated by a straight arrow. It is referred to below as the gas heat flow path 6l, the characteristic of which is indicated by the subscript "l".

[0122] In a typical differential scanning calorimeter, the overall apparatus is axially symmetric about a central axis that is perpendicular to each pan support area 4r on both the sample side and the reference side, such that both the sample side and reference side pan support areas 4r have circular peripheries, and each thermoelectric device snakes between an inner concentric circle of the thermoelectric junction and an outer concentric circle of the thermoelectric junction, thereby forming a sample side measurement area 5r and a reference side measurement area 5r that appear as projected rings surrounding the respective pan support areas.

[0123] The sample and reference parts of the calorimeter can each be modeled as shown in the circuit diagram in Figure 2. This model uses an analogy between electrical and thermal systems. Temperature differences are modeled as voltages, and heat flows are modeled as currents. Thermal resistances are modeled as electrical resistances, and heat capacitances are modeled as electrical capacitances. The heaters that generate the heating power are modeled as current sources. The temperature-controlled heat source functions similarly to ground in an electrical circuit.

[0124] The representation of the different parts of the self-calibrating differential scanning calorimeter is indicated by primed reference numbers of the respective parts.

[0125] In this circuit diagram, T F indicates the temperature of furnace 1', T T indicates the temperature of the sample / reference pan 2'. T m indicates the temperature in the pan support area 4'. The measured heat flow 6m' between the oven 1' and the pan support area 4' is measured by the measuring resistance R m At the furnace temperature level T f and the pan support area temperature level T m In parallel with this, the heat capacity C of the measurement area 5r is m is connected.

[0126] Thermal contact resistance R k is the temperature T m Pan support area and pan temperature T T Characterize the contact heat flow between the pan and the heat exchanger by the thermal contact resistance R k is governed by the unavoidable gap between the pan support area and the pan deposited on it. The contact resistance R k The heat flow path through is the contact heat flow path 6k'.

[0127] Gas Resistance R L is the furnace temperature T f Furnace 1' and pan temperature T T Characterize the gas heat flow path 6l' between the pan and the gas resistance R L depends on the calorimeter geometry and the measurement gas 8'. The gas resistance R L Connected in parallel to the sample / reference pan 2' is the heat capacity CT It is.

[0128] P * el represents the heat flow supplied to the sample / reference position, or the heating power produced by energizing the electric heater device 3′. P S symbolizes the heat flow experienced by the sample 7' in the sample pan 2s. P * DSC is the measurement resistance R m The measured heat flow is 6 m' through the tube.

[0129] The heat flow signal U generated by each or both measuring areas, preferably by a thermoelectric device, s , U r or differential heat flow signal U=U s -U r is one of the raw measurements and is the basis for determining the desired properties of the sample 7'. Another raw measurement is the heat flow P * el It can be said that:

[0130] The model shown in Figure 2 can be used for both the sample side and the reference side. The difference between the two is that there is no sample on the reference side, so the P * S = 0, whereas on the sample side, P * S =P S It is just the fact that it is.

[0131] In the following, P el,s and P el,r and P * el =P el,r On the sample side, P * el =P el,s In the following, P el should denote the differential heating power generated by energizing the electric heater device, i.e., Pel =P el,s -P el,r It is.

[0132] In the following, P DSCs and P DSCr respectively represent the heat flow in the sample on the reference side, i.e., P * DSC =P DSCr On the sample side, P * DSC =P DSCs In the following, P DSC represents the differential heat flow, i.e., P DSC =P DSCs -P DSCr It is.

[0133] The following formula:

number

number

number

[0134] In one embodiment of the present invention, the sample and reference side electric heater devices are controlled to minimize the differential measured heat flow. If this control were perfect, P DSC =P DSC,s -P DSC,r = 0. Since there is no sample on the reference side, no heat can be generated, so P* S From these relationships, the differential heating power P of the electric heater device is expressed as el (P el =P el,s -P el,r ) can be used to express

number

[0135] In another embodiment of the present invention, neither the sample side electric heater device nor the reference side electric heater device is energized. In this case, P * el =P el,s =P el,r = 0. Since there is no sample on the reference side, no heat can be generated, so P * S From these relationships, equation (4) gives the differential heat flow (P DSC =P DSC,s -P DSC,r ) can be used to express

number

[0136] In a further embodiment of the invention, the sample and reference side electrical heater devices are energized, but not enough to make the differential heat flow through the measurement region negligible. In such a case, equation (4) becomes:

number

[0137] Finally, there is no heat generated by the sample (P * S = 0), but with heating power generated only by the local heating device on either the reference side or the sample side, the following relationship is obtained from equation (7):

number

[0138] However, to evaluate equations (5) to (7), it is necessary to describe, on the one hand, the different thermal resistance terms and, on the other hand, to convert the measured or determined differential heat flow signal U into a differential heat flow P DSC A calibration factor is needed to link the

[0139] The first calibration factor is the ratio of a differential heat flow signal U detected while measuring the transition of an established reference material as a sample to a known heat flow value P of the established reference material under given measurement conditions. S During this measurement, no electric heater device is used. This first calibration factor is

number

[0140] Similarly, the second calibration factor is calculated for an electric heater device with a known differential heat flow P el The differential heat flow signal U measured while generating the el This second calibration factor can be written as the ratio of . No heat is produced by the sample during this measurement.

number

[0141] By applying the mathematical relationship in equation (6) which describes the situation in the absence of heating power by the local heater, the first calibration factor C H can therefore be expressed as follows:

number

number

[0142] By applying the mathematical relationship in equation (8) which describes the situation in the absence of heating power by the sample, the second calibration factor C E can therefore be expressed as follows:

number

[0143] However, the ratio F of the two calibration factors is independent of the measurement area and the sensor device and is proportional to the contact resistance R k and gas resistance R L It is determined solely by and depends on the ratio of

number

[0144] This independence from the sensor device allows the coefficient F to be determined for a set of possible measurement conditions for one DSC of a given type and the data to be reused for other instruments of the same type, or after changing the sensor device on the same instrument.

[0145] The contact resistance is dominated by the resistance of the thin gas layer between the pan and the pan support area, and this gas is the measurement gas that causes the gas resistance, so the specific thermal conductivity of the measurement gas is the fraction R k / R L and F can be considered as a numerical value that approximately describes the shape of the bread in the oven. This allows F to be calculated theoretically, for example by computer simulation.

[0146] Moreover, this observed independence from the sensor device allows the same F value to be used for different measurements using the same type of pan. To adapt the calibration to different temperatures and different measurement gases, a second calibration factor C can be obtained by using an electric heater device on one side of the sensor device. E can be determined.

[0147] C H In contrast to C E No reference material is required to determine C E can be determined at essentially any desired temperature, but C H The temperatures at which F can be determined are limited to the transition temperatures of known reference materials. Since F is nearly independent of temperature, C E By using and F, C H C for temperatures that cannot be measured directly H Values ​​can be interpolated.

[0148] Combining equations (7), (11) and (13) with the first and second conversion factors and the adjustment factor F to evaluate the heat flow to and from the sample gives:

number

[0149] This is C E and F.

number

[0150] The user can choose to use the electric heater device during the measurement, to use the electric heater device controlled to minimize the absolute value of the differential heat flow signal U, or to not use the electric heater device at all. This choice determines the U or P el may be set to 0 or may need to be measured and taken into account. In a preferred embodiment, F is selected based on the type of pan, and CE is determined before or after the measurement of the sample, which allows precise adaptation to the temperature at which the measurement is or should be performed, as well as to the measurement gas and its conditions during the measurement.

[0151] In this example, the calculation and definition of the calibration coefficients are explained using mathematical expressions in an easy to read format. The use of F and C in a self-calibrating differential scanning calorimeter E In carrying out the determination, the calculation is, for example, from the measured heat flow signal U to the measured heat flow P DSC and use these P instead of U to determine the heat flow to and from the sample. DSC The conversion factor F may be varied by providing intermediate results such as using a value of F. Furthermore, the inverse of the first and second calibration factors and / or of F may be used to realize the invention. Further variations in the selection of the sign of the differential quantity are possible. Thus, the second calibration factor is preferably any calibration factor determined by applying a differential heating power to the pan support area by using a local heater device and comparing this value with the measured differential heat flow signal U. Furthermore, the conversion factor F is preferably any coefficient characterizing the ratio between the thermal contact resistance and the thermal gas resistance. [Explanation of symbols]

[0152] 1 furnace 2 Pan (s: sample, r: reference) 3 Electric heater device (s: sample, r: reference) 4 Pan support area (s: sample, r: reference) 5. Measurement area with thermoelectric junction 6 Heat flow path 6m measurement heat flow path 6k contact heat flow path 6l Gas heat flow path 7. Sample 8. Measurement gas 9 Sensor device 10 Data Evaluation Unit

Claims

1. Second calibration coefficient C of differential scanning calorimeter Ｅ A method of determination, The differential scanning calorimeter described above is a. A temperature-controlled heat source, preferably a furnace (1), b. Includes a sensor device (9), wherein the sensor device (9) is i. Sample-side and reference-side pan support regions (4r) are adapted to receive the bottom regions of the sample pan (2s) and reference pan (2r) in thermally conductive contact, respectively. ii. The sample-side and reference-side measurement areas, respectively, that surround the pan support area (4r) on the sample-side and the reference-side, - Sample-side and reference-side measurement area sensors that can be operated to output a differential heat flow signal (U) representing the difference in heat flowing across the sample-side and reference-side measurement areas (5r), and / or - The heat flow signal on the sample side (U) represents the heat flowing across the measurement area on the sample side. Ｓ A sample-side measurement area sensor capable of outputting ) and a reference-side heat flow signal (U) representing the heat flowing across the reference-side measurement area. Ｒ A reference-side measurement area sensor that can be operated to output ) The measurement areas include the sample side and the reference side, iii. Local heater devices (3r) on the sample side and the reference side, adapted to apply heating power to the pan support regions (4r) on the sample side and the reference side, respectively. Includes, c. A sample pan of the desired type of bread is placed in the pan support region on the sample side, a reference pan of the same desired type of bread is placed on the pan support region on the reference side, and the volume surrounding the sample pan and the reference pan is filled with the desired measurement gas. The aforementioned method, a. A step of creating a first steady state of a desired temperature by using the heat source, b. Once the first steady state is reached, the step of applying heating power to either the pan support region (S) on the sample side or the pan support region (R) on the reference side by using each of the local heater devices in order to reach a second steady state, c. i. Direct measurement, or the difference U = U between the heat flow signal on the sample side and the heat flow signal on the reference side. Ｓ -U Ｒ The differential heat flow signal U is determined as follows, ii. During the second steady state, the differential heating power is the difference between the heating power applied to the sample side and the heating power applied to the reference side. The steps include determining the second calibration coefficient based on the ratio of, Methods that include...

2. a. The local heater devices (3r) on the sample side and the reference side are electric heater devices. b. The heating power applied to the sample side and the reference side, respectively, is determined by measuring the voltage and current between the two terminals of each of the electric heater devices. c. The electrical resistance R of each of the aforementioned electric heater devices. Ｓ , R Ｒ The second calibration coefficient C of the differential scanning calorimeter according to claim 1 is preferably evaluated as the ratio of the two measured values ​​and preferably stored together with the first steady-state temperature. Ｅ A method for determining this.

3. A second calibration coefficient C according to the method of claim 1 Ｅ A self-calibrating differential scanning calorimeter suitable for determining a. A temperature-controlled heat source, preferably a furnace (1), b. Includes a sensor device (9), wherein the sensor device (9) is i. Sample-side and reference-side pan support regions (4r) are adapted to receive the bottom regions of the sample pan (2s) and reference pan (2r) in thermally conductive contact, respectively. ii. The sample-side and reference-side measurement areas, respectively, that surround the pan support area (4r) on the sample-side and the reference-side, - Sample-side and reference-side measurement area sensors that can be operated to output a differential heat flow signal (U) representing the difference in heat flowing across the sample-side and reference-side measurement areas (5r), and / or - The heat flow signal on the sample side (U) represents the heat flowing across the measurement area on the sample side. Ｓ A sample-side measurement area sensor capable of outputting ) and a reference-side heat flow signal (U) representing the heat flowing across the reference-side measurement area. Ｒ A reference-side measurement area sensor that can be operated to output ) The measurement areas include the sample side and the reference side, iii. Local heater devices (3r) on the sample side and the reference side, adapted to apply heating power to the pan support regions (4r) on the sample side and the reference side, respectively. Includes, The self-calibrated differential scanning calorimeter further, c. A self-calibrated differential scanning calorimeter, comprising a data evaluation unit (10) capable of receiving the differential heat flow signal, and / or the heat flow signals on the sample side and the reference side, and the differential heating power and / or signals indicating the heating power applied to the sample side and the reference side, respectively, preferably the voltage and current between the terminals of each of the electric heater devices, d. The data evaluation unit, i. The second calibration coefficient C according to claim 1 Ｅ Execute the method to determine ii. Preferably, the determined second calibration coefficient C Ｅ Preferably, this is stored together with data describing the type of pan, the measuring gas, and the desired temperature in the first steady state. Includes memory having a set of instructions for, e. The data evaluation unit (10) preferably further comprises: i. Access or receive a conversion coefficient F that depends on the type of bread, ii. Based on the differential heat flow signal and / or the heat flow signals on the sample side and the reference side, and / or the differential heating power and / or the signals indicating the heating power applied to the sample side and the reference side, respectively, the conversion coefficient F and / or the second calibration coefficient C Ｅ In combination with the above, the heat flow to or from the sample in the sample pan is evaluated. A self-calibrating differential scanning calorimeter characterized by being equipped in such a way.

4. The data evaluation unit (10) has a first default calibration coefficient C that depends on the type of pan, the measured gas, and the temperature. Ｈｄ The data evaluation unit can access the data, and preferably further measures the heat flow to or from the sample in the sample pan, either by directly measuring the difference U = U between the heat flow signal on the sample side and the heat flow signal on the reference side. Ｓ -U Ｒ A self-calibrated differential scanning calorimeter according to claim 3, equipped to evaluate the differential heat flow signal, which is determined to be a certain value, as the ratio of the first default calibration coefficient.

5. A method for determining the conversion coefficient F using a differential scanning calorimeter, preferably a self-calibrated differential scanning calorimeter as described in claim 3 or 4, a. The second calibration coefficient C according to claim 1. Ｅ A method for determining the first desired temperature, comprising the step of performing the method at the first desired temperature, wherein the pan includes a calibration sample known to undergo an exothermic or endothermic transition at a transition temperature different from the first desired temperature. b. A step of controlling the heat source so that the transition temperature is achieved and the transition of the sample occurs while the local heater device on the sample side or the reference side is not applying heat, c. A step of integrating the differential heat flow signal U during the transition of the calibration sample and comparing the result with the theoretical enthalpy of the transition of the calibration sample, wherein the comparison is preferably performed by calculating the ratio of the first calibration coefficient C Ｈ The steps are saved as follows: d. The ratio of the first calibration coefficient to the second calibration coefficient (C Ｈ / C Ｅ The steps include: storing the conversion coefficient F, preferably together with the type of bread used in the measurement; Methods that include...

6. A method for determining the conversion coefficient F using a differential scanning calorimeter, preferably a self-calibrated differential scanning calorimeter as described in claim 4, a. The second calibration coefficient C described in claim 1 Ｅ The method for determining the third temperature is performed in the third step, b. The first default calibration coefficient C for the type of pan, the measuring gas, and preferably the third temperature. Ｈｄ Steps to access and c. The ratio of the first default calibration coefficient to the second calibration coefficient (C Ｈｄ / C Ｅ The steps include: storing the conversion coefficient F, preferably together with the type of bread used in this measurement; Methods that include...

7. A method for determining the conversion coefficient F of the type of pan placed in the oven in the sample-side pan support region, used in a self-calibrated differential scanning calorimeter according to claim 3 or 4, which preferably uses a given type of pan, a given furnace as a temperature-controlled heat source, and a sample-side pan support region, a. Assuming the thermal conductivity of the gas is 1, the geometric coefficient g is the thermal resistance between the given type of pan placed in the pan support region on the sample side and the furnace. Ｌ The steps include: estimating this preferably by computer simulation, b. A step of estimating the value of the transformation coefficient F based on the geometric coefficient g and the bottom radius r of the type of bread, Methods that include...

8. A method for evaluating the heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrated differential scanning calorimeter as described in claim 3 or 4, The differential scanning calorimeter described above is a. A temperature-controlled heat source, preferably a furnace (1), b. Includes a sensor device (9), wherein the sensor device (9) is i. Sample-side and reference-side pan support regions (4r) are adapted to receive the bottom regions of the sample pan (2s) and reference pan (2r) in thermally conductive contact, respectively. ii. The sample-side and reference-side measurement areas, respectively, that surround the pan support area (4r) on the sample-side and the reference-side, - Sample-side and reference-side measurement area sensors that can be operated to output a differential heat flow signal (U) representing the difference in heat flowing across the sample-side and reference-side measurement areas (5r), and / or - A sample-side measurement area sensor that can be operated to output a sample-side heat flow signal (US) representing the heat flowing across the measurement area on the sample side, and a reference-side measurement area sensor that can be operated to output a reference-side heat flow signal (UR) representing the heat flowing across the measurement area on the reference side. The measurement areas include the sample side and the reference side, iii. Local heater devices (3r) on the sample side and the reference side, adapted to apply heating power to the pan support regions (4r) on the sample side and the reference side, respectively. Includes, The aforementioned method, a. The steps of placing the sample in a sample pan of a certain type of bread, placing the sample pan in the bread support area on the sample side, and placing an empty reference pan of the same type of bread in the bread support area on the reference side, b. The step of controlling the temperature-controlled heat source in accordance with a desired temperature program, c. The step of measuring or determining the differential heat flow signal while no heat is being applied by the local heater device on the sample side or the reference side, d. The differential heat flow signal U, the conversion coefficient F, and the second calibration coefficient C Ｅ A step of estimating the heat flow to or from the sample using the following: the conversion coefficient F is selected according to the type of pan, and the second calibration coefficient C Ｅ The steps are selected by the type of pan, the measuring gas, and the measuring temperature, Methods that include...

9. A method for evaluating the heat flow to or from a sample in a sample pan using a differential scanning calorimeter as described in claim 8, The second calibration coefficient C Ｅ C Ｅ A method determined according to claim 1, without removing the sample pan or the reference pan between the determination of the heat flow described in claim 8 and the evaluation of the heat flow described in claim 8.

10. A method for evaluating the heat flow to or from a sample in a sample pan using a self-calibrated differential scanning calorimeter according to claim 3 or 4, The evaluation step includes at least one calibration step and measurement step, both of which are performed using the same type of pan and the same measurement gas. a. The calibration step is: i. The steps of placing the sample pan containing a calibration sample known to undergo an exothermic or endothermic transition at a certain transition temperature in the pan support region on the sample side, and placing an empty reference pan of the same type in the pan support region on the reference side, ii. A step of controlling the heat source such that the transition of the sample occurs when the transition temperature is achieved and no heat is being applied by the local heater device on the sample side or the reference side. iii. A step of integrating the differential heat flow signal U during the transition of the calibration sample and comparing the result with the theoretical enthalpy of the transition of the calibration sample, wherein the comparison is preferably made using a first calibration coefficient C Ｈ The steps are saved as follows: Includes, b. The measurement step is: i. The steps of placing the sample pan containing the sample of the target substance in the pan support area on the sample side, and placing an empty reference pan of the same type in the pan support area on the reference side, ii. A step of controlling the temperature-controlled heat source to conform to a desired temperature program while it is not being heated by the local heater device on the sample side or the reference side, iii. The step of observing the differential heat flow signal, Includes, c. The evaluation step described above is: i. The differential heat flow signal and preferably a first calibration coefficient C Ｈ A step of estimating the heat flow of the target substance to or from the sample from the comparison results of the calibration step, which are stored as follows: Includes, d. A method wherein preferably there are multiple calibration steps, each calibration step performed at a different transition temperature, the transition temperature preferably selected to be within a temperature range covered by the temperature program of the measurement step.

11. A method for evaluating the heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrated differential scanning calorimeter as described in claim 3 or 4, The differential scanning calorimeter described above is a. A temperature-controlled heat source, preferably a furnace (1), b. Includes a sensor device (9), wherein the sensor device (9) is i. Sample-side and reference-side pan support regions (4r) are adapted to receive the bottom regions of the sample pan (2s) and reference pan (2r) in thermally conductive contact, respectively. ii. The sample-side and reference-side measurement areas, respectively, that surround the pan support area (4r) on the sample-side and the reference-side, - Sample-side and reference-side measurement area sensors that can be operated to output a differential heat flow signal (U) representing the difference in heat flowing across the sample-side and reference-side measurement areas (5r), and / or - A sample-side measurement area sensor that can be operated to output a sample-side heat flow signal (US) representing the heat flowing across the measurement area on the sample side, and a reference-side measurement area sensor that can be operated to output a reference-side heat flow signal (UR) representing the heat flowing across the measurement area on the reference side. The measurement areas include the sample side and the reference side, iii. Local heater devices (3r) on the sample side and the reference side, adapted to apply heating power to the pan support regions (4r) on the sample side and the reference side, respectively. Includes, The aforementioned method, a. The steps of placing the sample in a sample pan of a certain type, placing the sample pan in the pan support area on the sample side, and placing an empty reference pan of the same type in the pan support area on the reference side, b. The step of controlling the temperature-controlled heat source in accordance with a desired temperature program, c. A step of controlling the local heater devices on the sample side and the reference side so that the absolute value of the differential heat flow signal is minimized, d. Preferably, the differential heating power P is obtained from the heating power of the local heater devices on the sample side and the reference side, similar to the differential heat flow signal U. ｅｌ A step to measure or determine, e. The differential heat flow signal U, the differential heating power P ｅｌ , the conversion coefficient F, and the second calibration coefficient C Ｅ A step of estimating the heat flow to or from the sample using the following: the conversion coefficient F is selected according to the type of pan, and the second calibration coefficient C Ｅ The steps are selected by the type of pan, the measuring gas, and the measuring temperature, Methods that include...

12. A method for evaluating the heat flow to or from a sample in the sample pan according to claim 11, a. The differential heating power P ｅｌ The gain k is set to minimize the absolute value of the differential heat flow signal U. ｐ Controlled by a proportional control device having, b. Preferably, the gain is a gain constant k and the default first calibration coefficient C Ｈｄ The gain constant k is selected according to the desired time resolution of the measurement, depending on the ratio of the first calibration coefficient C. Ｈｄ a method selected according to temperature, the type of pan, and the gas to be measured.

13. A method for evaluating the heat flow to or from a sample in the sample pan according to claim 11, The second calibration coefficient C Ｅ C Ｅ A method determined according to claim 1, without removing the sample pan or the reference pan between the determination of the heat flow described in claim 11 and the evaluation of the heat flow described in claim 11.

14. A method for evaluating the heat flow to or from a sample in a sample pan using a differential scanning calorimeter, preferably a self-calibrated differential scanning calorimeter as described in claim 3 or 4, The differential scanning calorimeter described above is a. A temperature-controlled heat source, preferably a furnace (1), b. Includes a sensor device (9), wherein the sensor device (9) is i. Sample-side and reference-side pan support regions (4r) are adapted to receive the bottom regions of the sample pan (2s) and reference pan (2r) in thermally conductive contact, respectively. ii. The sample-side and reference-side measurement areas, respectively, that surround the pan support area (4r) on the sample-side and the reference-side, - Sample-side and reference-side measurement area sensors that can be operated to output a differential heat flow signal (U) representing the difference in heat flowing across the sample-side and reference-side measurement areas (5r), and / or - A sample-side measurement area sensor that can be operated to output a sample-side heat flow signal (US) representing the heat flowing across the measurement area on the sample side, and a reference-side measurement area sensor that can be operated to output a reference-side heat flow signal (UR) representing the heat flowing across the measurement area on the reference side. The measurement areas include the sample side and the reference side, iii. Local heater devices (3r) on the sample side and the reference side, adapted to apply heating power to the pan support regions (4r) on the sample side and the reference side, respectively. Includes, The aforementioned method, a. Including at least one calibration step and measurement step, both performed using the same type of pan and the same measurement gas, and an evaluation step performed after the calibration step and the measurement step, b. The calibration step is: i. The steps of placing the sample pan containing a calibration sample known to undergo an exothermic or endothermic transition at a certain transition temperature in the pan support region on the sample side, and placing an empty reference pan of the same type in the pan support region on the reference side, ii. Preferably by the method described in claim 1, or the second calibration coefficient C for a given condition Ｅ By accessing the previously stored value of the second default calibration coefficient C Ｅｄ The steps to determine, iii. A step of controlling the heat source such that the transition temperature is achieved and the transition of the sample occurs while the local heater is controlled and the differential heat flow signal is minimized, iv. During the transition of the sample, the differential heating power P is present, similar to the differential heat flow signal U. ｅｌ A step to measure or determine, v. Over the time of the transition of the sample, - The differential heat flow signal U and, - The second default calibration coefficient C Ｅｄ and the differential heating power P ｅｌ Product of (P ｅｌ C Ｅｄ ) and the difference between them (U-P ｅｌ C Ｅｄ The step of integrating ) and vi. A step of comparing this integral value with the theoretical enthalpy of the transition of the calibration sample, wherein this comparison value is preferably the default second calibration coefficient C used in the integral. Ｅｄ Along with the first calibration coefficient C Ｈ The steps are saved as follows: Includes, c. The measurement step is: i. The steps of placing the sample pan containing the sample of the target substance in the pan support area on the sample side, and placing an empty reference pan of the same type in the pan support area on the reference side, ii. A step of controlling the temperature-controlled heat source in accordance with a desired temperature program, iii. A step of controlling the local heater devices on the sample side and the reference side so that the absolute value of the differential heat flow signal is minimized, iv. Similar to the differential heat flow signal U, the differential heating power P ｅｌ A step to measure or determine, Includes, d. The evaluation step described above is: i. The differential heating power P ｅｌ , the differential heat flow signal U, the default second calibration coefficient C Ｅｄ , and the comparison result of the calibration step, preferably the first calibration coefficient C Ｈ Using the sample P Ｓ Heat flow to sample P Ｓ Steps to estimate the heat flow from, Methods that include...

15. a. The conversion coefficient F is selected according to the type of pan and, preferably, the temperature of the temperature-controlled heat source. b. On the other hand, the measurement gas preferably has a second calibration coefficient C determined using the type of pan, the measurement gas, and preferably the temperature of the temperature-controlled heat source. Ｅ A method for evaluating the heat flow to or from a sample in a sample pan of the type of pan surrounded by the measuring gas described in claim 8, which is considered by selecting the appropriate option.

16. a. The sensor device is placed in a volume surrounded by the same temperature-controlled heat source, b. Preferably, a single detection unit includes the sensor device. A self-calibrating differential scanning calorimeter according to claim 3 or 4.

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