• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:AT510042A4
    申请号:T12932010
    申请日:2010-08-02
    公开日:2012-01-15
    发明作者:
    申请人:Anton Paar Gmbh；
    IPC主号:
    专利说明:

    • · 1 • · «« «· · * ······· ♦ ·····································································
    The invention relates to a method according to the preamble of patent claim 1 and a rotational rheometer according to the preamble of patent claim 11.
    In order to determine the flow behavior of complex, especially not ideal viscous liquids, solutions, melts, dispersions or gels up to solids, rotation tests are often carried out with rotary rheometers. Such a device is described for example in AT 404 192 B.
    In the conventional and rotary rheometers according to the invention, the liquid and / or solid samples to be determined are introduced into the measuring gap, which is formed between two measuring parts of defined geometry. For carrying out the experiment, differently shaped measuring parts can be attached to the intended stelite parts of the rheometer. By means of the control parts, the measuring parts are positioned relative to each other axially by mechanical lifting devices, possibly by means of control electronics, and thus form a measuring gap S defined height d. For this positioning units are known with exactly known linear feed as well as systems with additional length measuring system. The thickness of the measuring gap is determined by displacement sensors or distance sensors.
    The sample is subjected to a shearing load by rotation and / or oscillation of at least one of the measuring parts. Depending on the device type, the upper measuring part rotates, e.g. according to the Searle method, or the lower measuring part, for example a measuring cup, e.g. according to Couette method. The opposite of the sample medium of this rotation and / or shear resistance manifests itself in a torque acting on the measuring parts and is a measure of the Theological properties of the substance under investigation.
    The resulting torque and / or the phase position of the current absorbed by the drive motor is determined and fed to an evaluation unit. Different versions of rotary rheometers with combined drive and measuring motor are also known as separate arrangements of drive and torque measurement by a separate measuring motor on the other measuring part. The functional relationship between current consumption of the measuring motor and torque is known, the evaluation is then carried out by means of a connected evaluation unit.
    At the same time the measured turning angle! or the speed of the drive motor together with the torque acting translated into the theological parameters shear rate and shear stress and calculates the viscosity of the sample examined. For this purpose, in addition to the gap width d, the other parameters of the system must be known, e.g. Opening angle of the cone in a conical measuring part and its radius or the radii of the measuring cylinder in a cylinder measuring system.
    Experiments with a shear rate specification can also be carried out as with specification of a defined shear stress; Accordingly, the experiment is designed.
    The measured values for the thickness d of the measuring gap S with the displacement sensors are linked in the evaluation unit with the measured values relating to the moment of the substance to be examined and possibly the measured values of a normal force measuring device with which the forces exerted by the sample on the measuring parts are determined used to calculate the viscosity.
    The following applies to the shear viscosity η of ideal liquids in general: η = shear stress τ / shear rate (/)
    In a rotational viscometer in which a sample or substance is measured with the height h resulting from the thickness of the measuring gap S, which results between a stationary measuring part (plate) and a measuring part (plate) with a radius R rotating relative thereto , the following relationships apply to the shear rate D and the viscosity η: ω * R τ 2 * Μ 1 2 * M * h D <R) h η D (K) zr * / f 3 D [R] π * Κ ** ω
    At default, e.g. a constant torque M, changes the angular velocity ω in the same ratio as the height h, whereby the calculated viscosity remains constant. If, however, a height change is not taken into account in the calculation, the following error results for the viscosity η:
    If the height h - k * h (error factor k) is used, the actual angular velocity is determined: and for the determined viscosity: 2 * M * h
    K * R'i * D [! V * h h .... h '.., D (R) .. calculated sample height [m] actual sample height [m] ω. ω
    Shear rate at radius &quot; R &quot; [1 / s] ... calculated angular velocity [1 / s] ... actual angular velocity [1 / s] τ
    Shear stress [Pa] Μ ............................................. ........ torque [Nm] η ..................................... ..................... Viscosity [Pa.s]
    From the above derivation, it can be seen that in case of a measurement error of the sample height, the viscosity changes inversely proportional to the height ratio, i. a measurement error of + 1% results in a 1% reduction in viscosity. The thickness d of the measuring gap is usually t to 2 mm, whereby for a viscosity error of <1% the determination of the gap thickness with an accuracy of better than 10 pm or 20 pm is necessary,
    Therefore, the constant keeping of the thickness d of the measuring gap S is important and at least one readjustment takes place.
    In practice, it is attempted to take this circumstance into account by selecting a waiting time until the beginning of the measurement for a currently examined sample, which is based on empirically determined values or determined by preliminary tests on the material to be investigated.
    A proposed variant of checking the correct starting time for a measurement uses two temperature sensors in the upper and lower measuring part of the rheometer and determines when these two indicate the same temperature
    In addition, it is proposed to control the sample heating with both elements. If the same temperature has been reached in the upper and lower measuring sections, the stable measuring time should be reached. A problem with this approach is that each thermocouple, e.g. a Pt 100, depending on its properties has its own characteristic and must be adjusted by comparison measurement, a vote and balance between the two elements is always problematic and when controlling the sample heating with these two elements, the temperature drift in the sample is rather strengthened.
    In Fig. 1 and 2, a rheometer is shown, which is the starting point of the present invention and based on the rheometer according to AT 409304 B1.
    As already mentioned, the invention will be explained, for example, with reference to a plate / plate measuring system in which the sample 19 is located between a lower measuring part 1b formed as a fixed plate and an upper measuring part 1a formed as a rotating plate. The rotating plate 1a may be smaller Have dimensions as the fixed plate 1b,
    The measuring gap S can be determined and adjusted indirectly with a length measuring system 12, 13 which has an accuracy of <1 pm. As length measuring systems can transducer with resistance change (potentiometer), inductive displacement sensor
    (LVDT), or incremental transducers or gauges are used. Instead of a displacement measurement, a defined measuring gap S can also be set by the unit 50 is driven by the spindle 9 with a known pitch by measuring the angular rotation of the spindle with an angle encoder 10 height-adjusted. The disadvantage, however, is that these systems determine the distance between the unit 50 and the stand 11 and not directly the thickness d of the measuring gap S. Under constant environmental conditions (constant room temperature, constant and equalized sample and Meßsystemtemperatur) can thus Meßsystemspalte μ- However, practical experience shows that within the duration of the theological measurement of a sample, the change in the measuring gap can be a few 0.1 mm, caused by the following influences: thermal expansion and mechanical distortion of the stator 11 and thermal expansion of the Measuring parts 1a, 1b and the shaft 3, which results in an extremely high influence using temperature control chambers with a temperature range of -180 ° to 600 ° C, - Stativsteifigkeit and the stiffness of the shaft bearing 5, since viscoelastic substances under shear normal forces to some 10N to generate. High-end rheometers thus have a compensation device, which makes it possible to readjust the gap, for example via an empirically determined temperature / displacement function, and thus to keep it constant. Due to the mostly unknown temperature-equalization times, the multitude of measuring geometries and the different tempering chambers, a sufficiently good compensation can not be achieved in practice.
    The thickness d of the measuring gap S is expediently determined using a unit 22 formed by a displacement sensor which directly measures the distance between the measuring parts 1a, 1b without contact and adjusts, adjusts and / or keeps constant with the aid of the control unit 24. With a temperature measuring unit 21, the temperature of the measuring part 1a is determined.
    From the measured values, an output signal X = f (S) is obtained, which indicates the distance of the measuring parts as a function of the thickness of the measuring gap S. The unit 22 thus provides an electrical signal which is in a known function to the thickness of the measuring gap S. The output signals of the measuring unit 22 are sent to the control or evaluation unit 24 for further use, in particular for adjusting or readjusting or keeping constant the measuring gap or for evaluating measuring results or for calculating desired values, e.g. Viscosity values supplied.
    Furthermore, the temperature dependence of the output signals of the unit 22 is additionally to be considered.
    The temperature is measured with a temperature sensor 21, which may be placed in the unit preferably formed by a displacement sensor or as close as possible to it. The circuit 51 or the subsequent evaluation unit 24 is supplied with the temperature measurement, whereby the influence of the temperature on the measured value of the thickness d of the measuring gap S can be largely compensated. The temperature dependence of the measuring unit 22 or of the displacement sensor is determined empirically in a reference run, in that the temperature is traversed within the range of application at different constant gap sizes.
    For example, a decrease in temperature in the sample and / or in its environment usually leads to a gap widening; the samples contract and the dimensions of the measuring parts, of the stand and of the measuring shaft given by thermal expansion decrease overall, the gap becomes larger. The mechanical feed or the adjustment unit of the unit 50 must therefore reduce the thickness d of the measuring gap S in order to keep the gap thickness the same.
    Alternatively, a heating of the sample and / or its surroundings leads to a gap narrowing, in particular by a flow of the samples and expansion of the components of the rheometer, in particular of the statics, the actuators and the measuring parts. Here, the rheometer can react by mechanical readjustment with regard to a gap extension.
    In both cases, the gap width is readjusted until a constant, set or predetermined measuring temperature is reached, and thus the thickness d is readjusted against its thermally induced change d in order to keep the gap height constant.
    The sequence of a measurement now takes place in the steps
    Insertion of the sample 19 between the two measuring parts 1a, 1b and adjustment of the thickness d of the measuring gap S between the two measuring parts 1a, 1b to the desired gap thickness
    Temperature control of the sample 19 by means of temperature specification to a not shown heating / cooling device of the rheometer, wherein the o temperature is measured near or at the surface of the sample 19 and / or at a measuring part 1a, 1b with the sensor 21 and based on this value o heating / cooling device is controlled with the control and evaluation unit 24 until reaching the predetermined measurement temperature setpoint by means of the control and evaluation of the rheometer.
    This raises the problem of when to start with the measurement, since the adjustment or control of the measurement temperature in the sample 19 is accompanied by changes in the thickness d of the measuring gap S. To set a time for the start of measurement is at a method of the type mentioned initially provided, - that starting with the time at which at least a portion of a Messteiis reaches the predetermined measurement temperature or its temperature has fallen below a predetermined distance to this measurement temperature, for the changing thickness of the measuring gap and / or the thickness change or readjustment speed, in particular running, at predetermined measuring times and / or for predetermined time intervals limited by predetermined measuring times, are determined, and only when these measured values have fallen below a certain predetermined threshold is the measurement of the theological parameters begun ,
    According to the invention, even after reaching the
    Measuring temperature setpoint on the sensor 21, the remaining temperature drift monitored by the observation of the required Dickennachstellwertes the measuring parts and / or the Abstandsänderungs- or readjustment speed of the measuring parts and / or changing per unit time distance of the measuring parts. The measured values determined for this purpose allow a more accurate prediction or determination as to whether the required temperature compensation has taken place in the sample to be investigated or for the measuring gap and the entire system is stable. For this purpose, the thermal expansion rates ΜΙΔΤ of the overall system can be determined, since any temperature drift in the system due to the thermal change of the
    Sample properties and the rheometer geometry causes a change in the sample geometry and thus there is a change in the gap geometry. This change is compensated by descending the mechanical lifting device or unit for adjusting the gap thickness. As part of this review, the achievement of a desired accuracy class can be determined and the precision level reached can be determined and displayed and evaluated based on the maximum remaining changes. Only then does the start of the measurement and the output of the theological parameters and / or storage of the same take place in the evaluation unit. The entire process can be automated via the control and evaluation unit of the rheometer after prior selection of the accuracy class. It is thus provided that the difference value of the measured values determined for these two measuring times is formed for two selected measuring times, and / or for a selected one of two 7 * * * «« ··· * · / · * ··· · · · * * * »I * * * * * ··························································································································································································································· - that the determined difference value is compared with a predetermined threshold value, and - that depending on the comparison, the input or readjustment or constancy of the thickness of the measuring gap as done and considered sufficient and started with the measurement of the rheometric parameters is, or - that is continued with the determination of a further formed difference value and its comparison with the threshold and evaluation of the comparison.
    According to the present invention, the instantaneous thickness d of the measuring gap S is determined at certain times, that is to say at certain measuring times or the changes in thickness which have occurred are measured at predetermined measuring times, or the respective rates of change in thickness are measured at certain measuring times or is determined for certain time intervals, resulting for the respective time interval thickness change or the occurred thickness change rate. Particularly when a readjustment of the measuring gap S to a constant value of the thickness d of the measuring gap S occurs, these measured values result from the adjustment movements made by the device for keeping the measuring gap constant for the two measuring parts 1a, 1b relative to each other. The paths or the speeds with which the readjustment takes place are carried out by the adjusting unit or by the unit 50 which adjusts the unit 50, and are determined as measured values at the respective measuring times or for the respective time intervals.
    It is possible to form the difference values between measured values determined in each case for successive measuring times. It is preferred to determine the measured values at measuring times, between which a number of further measuring times are located, for which measured values were likewise determined, which at most are also used to form further difference values. The same applies to the determination of the difference values for the measured values determined for time intervals. As such, measured values can be determined continuously. However, it is expedient to keep the cycle times or the time interval between the individual measurement times relatively low and to select the measured values for forming the difference values such that greater time intervals between the times at which measured values are selected for forming the difference values than between the measurement times lie. It is useful if the distances between the measuring times are equal to each other and / or the time intervals for determining the
    Measured values are always the same length and / or that the time interval of the predetermined measurement times are limited.
    It is expediently provided that the measured values for the thickness and / or the readjustment values required for the readjustment or constant thickness control and / or the required changes in the thickness change rate are used for the formation of difference values, optionally such that these values have been determined at two selected measurement times whose time interval is such that at least one further measurement time lies between these two selected measurement times, or were determined for selected measurement times which are at the beginning and at the end of a selected time interval formed by a plurality of successive time intervals. It is provided according to the invention that the first measuring time and / or the beginning of the time interval for determining the further difference value lies at a later time than the measuring time and / or the beginning of the time interval for and / or the previously compared difference value. Thus, the course of the change of the measuring gap S is detected until the readjustments made fall below a predetermined threshold value and are no longer considered to be relevant for the measurement.
    It is expedient for the measured values of the rate of change of thickness to be determined for selected time intervals which comprise at least two time intervals.
    According to the invention, it is provided that a plurality of threshold values of different levels is predetermined and, depending on the desired measurement accuracy of one of these threshold values, is used for the comparison. By selecting the threshold values, the beginning of the first measurement is shifted until the measured values or the difference values lie below a predefined threshold value, that is to say the change in the thickness and / or the rate of change of the measurement gap is below a predefined value, with which the accuracy class of the subsequently started measurement is determined.
    It can further be provided that, when the time Z is reached, the measuring parts and / or a sample chamber surrounding the sample are thermostated and / or the predetermined measuring temperature reached is kept at a constant value. Thus, a required readjustment of the measuring gap by thermal influences is largely minimized.
    A rotation rheometer according to the invention of the type mentioned above is according to the invention, characterized in that - the control and recording unit comprises a measuring unit, with the measured values for the thickness starting at a specific time at predetermined measuring times * ···> c · · ♦ * * * * * * T * * * * * * t * * »and / or for the readjustment value required for the compensation of the change in thickness of the measuring gap and / or for the thickness change or readjustment speed of the measuring gap required within a preceding time interval Measuring gap or for determined by the measuring time intervals, - that the measured values are fed to a comparison unit, with which the respective values are comparable to a predetermined threshold, - and that the output signal of the comparison unit of the control and evaluation unit is supplied. It is advantageous if the measuring unit is assigned a difference former, with which difference values of measured values determined at selected measuring times or for selected time intervals are formed and these are supplied to the comparison unit.
    In order to determine the measuring times, it is provided that the measuring unit comprises a clock for establishing or determining the predetermined time intervals and the predetermined measuring times. With this rheometer the measuring accuracy can be further increased. Furthermore, desired accuracy can be better defined or maintained. In order to determine accuracy classes for the measurement, it is provided that the comparison unit has a threshold value store in which a plurality of threshold values are stored.
    The invention further relates to a data carrier on which a program for carrying out the method according to the invention is stored or a computer program with program code means, configured for carrying out the method according to the invention, if this program is executed on a computer or a computer program stored on a data carrier is, or a data carrier with electronically readable control signals, which can cooperate with a programmable computer system so that a method according to the invention is carried out. Finally, the invention relates to a computer program product with program code for carrying out the method according to the invention when the program is executed on a computer.
    The invention will be explained below by way of example with reference to the drawings. 1 shows a rheometer according to the invention, FIG. 2 shows a detail from FIG. 1, FIGS. 3, 4 and 5 show diagrams relating to measured value profiles.
    Fig. 1 shows - as already mentioned above - schematically a Rotationsrheometer with a combined drive and measuring motor 2, a rotary and drive shaft 3, an angle encoder 4 and a frictionless storage 5, which is shown here as an air bearing schematically without supply lines. A device 6 for normal force measurement, which can be realized with arbitrary measuring units, is embodied here in the form of a position sensor or distance measuring device on the air bearing.
    Trained as plates measuring parts 1a and 1b are easily interchangeable by a quick release 31 on the measuring and drive shaft 3 and a removable holder for the lower measuring part 1b. The adjustment of the thickness of the measuring gap 5 via the height adjustment of a lifting table 50 which is mounted axially displaceable axially adjustable relative to the stand 8. In the measuring gap S between the two measuring parts 1a, 1b is the sample to be examined 19th
    In general, the thickness d of the measuring gap S can be measured indirectly via the detour of the stand 8 and the lifting table 50 with a length or distance measuring system 12, 13. As length or distance measuring systems can with transducers
    Resistance change, inductive displacement sensor, incremental transducer, gauges od. Like. Find use. Instead of a displacement measurement, a measuring gap S defined thickness d can be adjusted by the lifting device 50 is adjusted via a spindle 9 of known pitch with thrust bearing 9a and motor 9b and the measurement of the spindle angle with the angle encoder 10. Instead of the spindle drive, other linear drives can be used, for example, a Uhnig-mother drive (rolling bearings), linear motors, pneumatically driven adjusting devices.
    In alternative arrangements, the lower measuring part can be made height adjustable and the upper measuring part together with the engine block is fixed to the tripod.
    The rotational rheometer shows even with a small change in the thickness d of the measuring gap S influence on the accuracy of the results, the gap is according to the above equation in the calculated result to the viscosity, thermal effects play a major role.
    The gap change results in a temperature change as a sum of thermal expansion and mechanical distortion of the tripod 8. thermal expansion of the upper and lower measuring part 1a, 1b and the measuring shaft 3 and the stator stiffness and stability of storage.
    High-end rheometers have a compensation device that adjusts the thickness d of the measuring gap S via an empirically determined temperature / displacement function and thus keeps it constant. Also possible is the direct determination of the distance between the two measuring parts and the direct compensation of the changes in the gap thickness.
    In this case, the distance between the two measuring parts, which form the measuring gap S, while still set by a mechanical lifting device on the tripod, the actual thickness d of the measuring gap S is no longer indirectly but measured without contact directly between the two measuring parts 1a and 1b. In this case, one of the two measuring parts carries the displacement sensor, while the respective other measuring part carries the component influencing the displacement sensor or influences the component itself. The output signals of the displacement sensors are fed to the evaluation unit and thus allow the distance between the measuring parts to be measured and / or adjusted and / or kept constant. Advantageously, it is provided that with the output signals of the displacement sensors, a device for changing or adjusting or readjusting the measuring gap is controlled by height adjustment of at least one of the two measuring parts. Usually, a height adjustment of the lifting table.
    2 shows non-contact measuring sensors 22 for the distance measurement integrated into the lower measuring part 1b, together with the temperature measuring element 21, which optionally corrects a temperature-dependent measured value of the contactless distance sensors working according to calibration and / or simultaneously measures the sample and measuring temperature. The size X thus determined as a function of the distance s is transmitted to the control and evaluation unit, optionally via the linking unit 51, where it is available for height correction or readjustment of the measuring device via the mechanical lifting system. This variable can be, for example, the impedance value of an inductive sensor.
    A temperature drift of the system negatively influencing the measuring accuracy can thus be compensated for by adjusting or descending the measuring parts with the unit for mechanical gap adjustment.
    In many experimental settings, the sample temperature is an important parameter. The behavior of substances is characterized depending on their temperature, for example, temperature-dependent yield stress can be determined by experiments in tempered chambers and / or measuring parts. Usually find tempering with selectable experimental temperatures in the range of -180 ° C up to 600 ° C and above use, measuring parts and chambers with Peltier elements, electrical heating and flow with tempered gases are state of the art.
    In general, the sample temperature in one of the two measuring parts 1a, 1b or near the sample is measured by means of thermocouple 21 (see FIGS. 1 and 2) and the tempering chamber and / or heating device of the measuring parts are thus controlled or regulated.
    After a temperature change in the sample which is adjusted by means of a heating element in a measuring part and / or in a tempering chamber, a certain time elapses until the sample is at the setpoint temperature. In addition to the selected measuring body and the gap geometry, the heat conductivity and / or heat capacity of the sample also plays a major role. In particular, temperature control chambers with a uniform heating of sample and / or measuring parts 1a, 1b and measuring shaft 3 may take a longer time until thermal equilibrium is reached at the temperature setting. Structurally stable samples are measured several times and the measured values or the viscosity values in the evaluation unit are determined until these viscosity values no longer show any drift, with the result that a multiple test procedure is required.
    Especially in the case of materials which structurally change during the measurement, e.g. Polymers, pseudoplastic samples with high relaxation times, e.g. Yoghurt, but the way of multiple measurement is not available, since every single measurement changes the sample and thus affects the result. Here, the invention provides a remedy.
    FIGS. 3 and 4 show, for two different gap widths and samples with poor thermal conductivity, the development of the viscosity η measured with a rotational rheometer, for example according to AT 409304 A1, and the thermal expansion rates V of this system as the rate of gap readjustment (v = Ad / At) a temperature jump, plotted over time t. The temperature measurements T of the sensor 21 show the temperature development near the surface of a measuring part. While the gap thickness is kept constant by the control unit 24, the size V = Ad / At, the speed or movement specifications of the mechanical, the gap thickness continuously readjusting the lifting system 9, 9a, 9b, 10 clearly shows the slower and slower setting or Wachregelung the measuring gap S,
    In FIG. 3, starting from a temperature of 150 ° C., the sample 19 is cooled to 20 ° C. in a measuring gap S of the gap width or thickness d = 0.047 mm. After reaching this target temperature TM at the temperature sensor 21, the viscosity measurement was started on a structurally stable sample 19 and recorded the control variable of the lifting or gap control system 50 for determining the Theological parameters. While the measured with the sensor element 21 from this time temperature T remains constant, you can clearly see the further taking place gap change or the course of the required adjustment due to the slower adjusting * * * φ · «· · φ» · · φφ »· φφ Φ · · · · · thermal equilibrium in the sample or in its environment. The readjustment speed v is given as measured values for the readjustment.
    The graph clearly shows the correlation of the measured viscosity η, which is expected to approach the basic or final value nFinal after reaching the thermal equilibrium in the sample 19, with the measured rate of change or expansion of the gap system. This means that a measurement of the parameters was started too early at time Z,
    In the case of FIG. 4, a sample 19 was heated in a gap of 1 mm gap height, starting from 50 ° C. to 150 ° C., and here too this correlation is clearly recognizable. At time Z, the gap thickness has not yet reached the preset final value, due to thermal changes in thickness in the sample and changes in length of the individual components in the system, the readjustment speed changes over a considerable period of time. The measuring temperature was reached after about 3 minutes, the readjustment of the measuring gap is not completely completed at 20 minutes. The Nachregelungsgeschwindigkeit and the required travel distances are decreasing more and more, so that from a certain selectable time, when a desired accuracy for the measurement of the parameters is reached, the ever decreasing Nachregelungswerte can be neglected. After about 20 minutes, the still occurring Nachregelgeschwindigkeit could be neglected and the measurement of the parameters are started.
    Depending on the desired accuracy of the measurement, the measurement after reaching the required or desired temperature compensation or after reaching or exceeding or falling below - depending on the location and choice - a predetermined threshold for the current gap change the measurement is started.
    In an advantageous embodiment variant, test intervals or time intervals with a constant time duration, e.g. of 200 seconds, defined and the slope of the determined in this selected time interval Nachregelungsgeschwindigkeit and / or the associated change in thickness of the measuring gap determined and treated as a linear function. The slope of the movement curve in this time interval can be used as a measured value. For this purpose, in each case the slope of the adjustment curve is calculated using the measured values of the time interval or the differential value of the slope Measured values at the beginning and end of the time interval are determined and it is compared whether these are already smaller than a predefined threshold value for a desired accuracy category. For a standard measurement, for example, the threshold value for the gap movement can be set to <2 pm/200s, for precision measurement to below 0.5pm / 200s.
    In this case, at a small time interval to predetermined measuring times, for example, measured values are determined every 10 seconds, a new selected measuring interval is started, i. the measured values of the gap movement are z. Every 10 seconds for one or a selection of selected time intervals of e.g. 200 seconds and the measured value determined for the entire selected interval is used for comparison purposes. This means that the measured values are used to form several selected intervals, which intervals are formed with a time lag behind each other.
    FIG. 5 shows a diagram in which the absolute thickness d absolute of the measuring gap S and the relative thickness d ".iativ or the rates of change of thickness as well as the temperature T are plotted against the time t. It can not be seen that the gap thickness has not yet reached its final value at time Z, and that after about 20 minutes the readjustment of the gap or the rates of change in the thickness change approach a minimum. A measurement with predetermined accuracy could thus be started at time TM,
    By specifying constant selected time intervals and determining the time intervals, e.g. 200 seconds, resulting changes in the gap thickness, the determined for the respective time intervals difference values Ad / At, formed with the measured values beginning and at the end of each selected time interval, the threshold and the difference value is compared with the threshold value.
    If equally long time intervals are present, the rate of change for the readjustment of the measurement gap immediately after time Z is greater and the distance of the gap thickness from the desired value of the gap thickness greater than for a time interval which has a considerable distance from time Z. In this latter time interval, the change in the measured value for the readjustment speed is substantially lower than in the first time interval lying immediately after time Z. A comparison of the measured or difference values obtained for the first and for the latter time interval with one and the same threshold value can result in the threshold being regarded as exceeded for the first measuring interval and being considered as being undershot for the latter measuring interval. In FIG. 5, a suitable time for a measurement of the parameters could be, for example, the time tm, * * ms:
    It can be provided that, starting with time Z, a time interval is formed with a predetermined number of measured values held constant. Such a time interval could contain, for example, 20 measured values, for example the measured values 1 to 20. A time interval formed next could contain the measured values 2 to 21, the next time interval the measured values 3 to 22, so that continuously selected time intervals are available whose measuring or Difference values can be compared with a selected threshold for a desired accuracy class.
    The specified difference values are the change values of the measured values for specific time intervals. These difference values can be formed with the thicknesses d of the measuring gap S measured at the beginning and at the end of the selected time interval. This difference value can also be a change in a readjusting speed, for which the speed of the readjustment or for the entire time interval is determined at the beginning and at the end of the interval. Such a difference value may be formed with the changes in the thickness values of the measuring gap, measured at the beginning and at the end of the time interval. Depending on the length of the interval or the distance of the measurement times, larger or smaller increases result in difference values. In particular, it is expedient to approximate the measured curves resulting from the readjustments of the gap thickness for particular time intervals by straight lines, since this simplifies the calculation of the difference values.
    权利要求:
    Claims (15)
    [1]
    1. A method for determining rheometric parameters of samples (19) with a Rotationsrheometer, wherein the thickness (d) of the measuring parts (1a, 1b) limited measuring gap (S) with a measuring unit (22) measured and a predetermined thickness value at a change or adjustment of the measuring temperature to a predetermined measuring temperature setpoint is adjusted or readjusted or kept constant, characterized in that - starting from the time (Z) to which at least a portion of a measuring part (1a, 1b) the predetermined measuring temperature (TM) has reached or has fallen below a predetermined distance from this measurement temperature (TM), for the changing thickness (d) of the measuring gap (S) and / or for the thickness change or Nachregelungsgeschwindigkeit (Ad /, At), in particular running, too predetermined measurement times and / or for predetermined, limited by predetermined measurement times time intervals measured values are determined, and only if this measurement values have fallen below a certain predetermined threshold, the measurement of the theological parameters is started.
    [2]
    2. The method according to claim 1, characterized in that - for two selected measuring times in each case the difference value of the measured values determined for these two measuring times is formed, and / or for a selected time interval delimited by two selected measured values a difference value of the beginning and the end - that the determined difference value is compared with a predetermined threshold value, and - that depending on the comparison, the input or readjustment or constancy of the thickness (d) of the measuring gap (S) as done and considered sufficient and with the measurement of the rheometric parameters is started, or - that the determination of a further difference value formed and its comparison with the threshold value and evaluation of the comparison is continued.
    [3]
    3. The method according to claim 1 or 2, characterized in that the distances between the predetermined measuring times and / or the time intervals are chosen to be equal to each other and / or that the time intervals are limited by the predetermined measuring times.
    [4]
    4. The method according to any one of claims 1 to 3, characterized in that for the formation of difference values, the measured values for the thickness (d) and / or the Nach st for the readjustment or constant thickness required st eil values and / or the If necessary, these values were determined at two selected measurement times, the time interval is such that between these two selected measurement times at least one further measurement time is, or were determined for selected measurement times, the beginning and at the end of a selected time interval formed by several consecutive time intervals.
    [5]
    5. The method according to any one of claims 1 to 4, characterized in that the first measuring time and / or the beginning of the time interval for the determination of the further difference value at a later time than the measuring time and / or the beginning of the time interval for and / / or the previously compared difference value has been determined.
    [6]
    6. The method according to any one of claims 1 to 5, characterized in that the measured values of the thickness change rate are determined for selected time intervals which comprise at least two time intervals.
    [7]
    7. Method according to claim 1, characterized in that a plurality of threshold levels of different values are specified and, depending on the desired accuracy of measurement, one of these threshold values is used for the comparison,
    [8]
    8. The method according to any one of claims 1 to 7, characterized in that from reaching the time (Z) the measuring parts (1a, 1b) and / or a sample (19) surrounding the sample chamber are thermostated and / or reached, predetermined measurement temperature is kept at a constant value.
    [9]
    9. The method according to any one of claims 1 to 8, characterized in that the measuring signal of the measuring unit (22) for determining the thickness (d) of the measuring gap (S) is temperature-compensated,
    [10]
    10. The method according to any one of claims 1 to 9, characterized in that starting with the time (Z), the temperature drift of the thickness (d) of the measuring gap (S), that is, by changing the temperature of the sample (19) in their approximation Changes in thickness of the measurement gap (S) caused by the measurement temperature, the change in the thickness (d) of the measurement gap (S) are further measured, and the thickness (d) is continuously adjusted or adjusted to the predetermined thickness value.
    [11]
    11. rotational rheometer with a control and recording unit (24) for the rheometric parameters of a sample (19) derived from the measuring parts (1a, 1b) with a measuring unit (22) for determining the thickness (d) of the measuring parts (1a, 1b) limited measuring gap (S) and one of the measuring unit (22) controlled adjusting unit (9, 9a, 9b, 10) for adjustment or readjustment or to maintain the thickness (d) to a (m) predetermined thickness value by adjusting or adjusting the Distance of the measuring parts (1a, 1b), characterized in that - the control and recording unit (24) comprises a measuring unit (30), starting at a certain time (Z) at predetermined measuring times measured values for the thickness (d) and or for the readjustment value for the compensation of the change in thickness of the measuring gap (S) which has been required within a preceding time interval and / or for the thickness change or readjustment speed of the measuring gap (S) or f for the time intervals determined by the measuring times, that the measured values are fed to a comparison unit 32, with which the respective values are comparable to a predetermined threshold value, and that the output signal of the comparison unit 32 of the control and evaluation unit 24 ) is supplied.
    [12]
    12. A rotational rheometer according to claim 11, characterized in that the measuring unit (30) is associated with a difference former (31) with which difference values of measured values determined at selected measuring times or at selected time intervals are formed, and these difference values are supplied as measured values to the comparison unit.
    [13]
    13. rotational rheometer according to claim 11 or 12, characterized in that the measuring unit (30) comprises a clock for establishing or determining the predetermined time intervals and the predetermined measurement times.
    [14]
    14. rotational rheometer according to one of claims 11 to 13, characterized in that the comparison unit (32) has a threshold value memory, in which a plurality of threshold values is stored,
    [15]
    15. Data carrier on which a program for carrying out a method according to one of claims 1 to 10 is stored, and / or computer program with program code means adapted to carry out a method according to one of claims 1 to 8, when the program is executed on a computer , and / or computer program according to one of claims 1 to 8, stored on a data carrier, and / or data carrier with electronically readable control signals, which can interact with a programmable computer system such that a method according to one of claims 1 to 8 is executed, and / or computer program product with program code for carrying out the method according to one of claims 1 to 8, when the program is executed on a computer. -Wien, at 3, Augtrsr2fr10
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    同族专利:
    公开号 | 公开日
    GB2482603A|2012-02-08|
    AT510042B1|2012-01-15|
    DE102011109140B4|2019-05-16|
    GB2482603B|2014-08-13|
    US8904852B2|2014-12-09|
    DE102011109140A1|2012-05-16|
    US20120024047A1|2012-02-02|
    GB201113302D0|2011-09-14|
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    AT404192B|1996-05-02|1998-09-25|Anton Paar Gmbh|ROTATIONAL VISCOSIMETER|
    DE19911441A1|1999-03-04|2000-09-07|Anton Paar Gmbh Graz|Rheometer for rotation viscometers with cylinder measuring system has measurement vessel and thermostat making heat-conductive contact only in their upper region, particularly around upper periphery of measurement vessel|
    AT409304B|1999-09-24|2002-07-25|Anton Paar Gmbh|Rotational|
    DE10058399A1|1999-11-29|2001-05-31|Anton Paar Gmbh Graz|Rotation rheometer, has heat pump, especially Peltier block, provided to heat, cool or temperature regulate upper measurement part with gap to lower measurement part|
    DE10260981A1|2002-12-21|2004-07-01|Thermo Electron Gmbh|rheometer|
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    JPH06129974A|1992-10-15|1994-05-13|Matsushita Electric Ind Co Ltd|Rotative viscosity gauge|
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    AU2002950831A0|2002-08-16|2002-09-12|Gbc Scientific Equipment Pty Ltd|Rheometer|
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    FR2873444B1|2004-07-22|2007-03-02|Univ Pasteur|PIEZORHEOMETER MEASUREMENT CELL AND CORRESPONDING PIEZORHEOMETER|
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    AT508237B1|2009-04-28|2011-05-15|Anton Paar Gmbh|METHOD AND DEVICE FOR DETERMINING THE RHEOLOGICAL PROPERTIES OF MEDIUM SAMPLES|DE102012014737A1|2012-07-26|2014-01-30|Basf Coatings Gmbh|Stator plate for rotating- or oscillating rheometer, has annular rotating or oscillating measuring head, while annular groove is formed on upper surface of stator plate for receiving sample to be examined|
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    AU2014402304B2|2014-07-31|2017-12-21|Halliburton Energy Services, Inc.|Variable diameter viscometer for evaluating well fluids|
    US10695729B2|2016-03-24|2020-06-30|Highland Fluid Technology, Inc.|Optimizing drilling mud shearing|
    US10613010B2|2017-12-06|2020-04-07|Ametek, Inc.|Intertial torque device for viscometer calibration and rheology measurements|
    AT520990A1|2018-03-01|2019-09-15|Anton Paar Gmbh|rheometer|
    US10761078B2|2018-09-04|2020-09-01|Lincoln Industrial Corporation|Apparatus and methods for testing oil separation from grease|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    AT12932010A|AT510042B1|2010-08-02|2010-08-02|METHOD FOR DETERMINING RHEOMETRIC PARAMETERS OF SAMPLES AND ROTATIONAL RHEOMETERS|AT12932010A| AT510042B1|2010-08-02|2010-08-02|METHOD FOR DETERMINING RHEOMETRIC PARAMETERS OF SAMPLES AND ROTATIONAL RHEOMETERS|
    DE102011109140.1A| DE102011109140B4|2010-08-02|2011-08-01|Method for determining rheometric parameters of samples and rotational rheometers|
    GB201113302A| GB2482603B|2010-08-02|2011-08-02|Rheometer|
    US13/196,451| US8904852B2|2010-08-02|2011-08-02|Method for establishing rheometric parameters of samples and rotational rheometer|
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