• 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:
    In a measuring method for measuring the viscosity of a substantially non-compressible measuring medium (F) with a first container (2) having measuring device (1), wherein from the first container (2) the measuring medium (F) via a in Operating position in a certain capillary angle (α) to the horizontal, preferably perpendicularly arranged capillary (11) via an outlet opening (13) of the capillary (11) can leak, in a first process step, the measuring medium (F) in the with a compressible medium , in particular ambient air (L) filled first container (2) introduced, after which the measuring medium (F) fills a partial volume (VF0) of the total volume (V0) of the first container (2), wherein in a second process step depending held a first Pressure difference (Δp1) and a second pressure difference (Δp2) kept constant or a pressure difference Δp (t) decreasing over time between a pressure (p1 or p2; p (t)) of the compressible Me in the first container (2) and a pressure (p0) of the compressible medium (L) at the outlet opening (13) of the capillary (11), wherein in a third method step the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit of time for the first pressure difference (Δp1) kept constant and the second pressure difference (Δp2) kept constant or for one due to the volume decrease (dVF (t) / dt) of the measuring medium (F) decreasing first pressure difference (Δp (t)) is determined to at least two measurement points of the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit time on the pressure difference (Δp) as the result straight line (14) in a coordinate system determine, in a final method step, the kinematic viscosity (v) from the value (15) of the result line (14) for the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit time at the pressure difference of Δp = 0 and the dynamic viscosity (η) of the measuring medium (F) from the S teigung the result line (14) is determined.
    公开号:AT518658A4
    申请号:T50014/2017
    申请日:2017-01-12
    公开日:2017-12-15
    发明作者:Wolfgang Belitsch Dr
    申请人:Wolfgang Belitsch Dr；
    IPC主号:
    专利说明:

    Viscometer for determination of dynamic and kinematic viscosity
    The invention relates to a measuring method for measuring the viscosity of a substantially incompressible measuring medium with a measuring device having a first container, wherein the measuring medium can flow out of the first container via a capillary and via an outlet opening of the capillary.
    Such a measuring method and such a measuring device are known from the document AT 508 276 Bl. In the measuring method disclosed in this document, the following method steps are carried out to measure the dynamic viscosity η as the physical size of a substantially incompressible liquid measuring medium: in a first method step, the measuring medium is introduced into a container filled with a compressible medium, after which the measuring medium fills a partial volume of the total volume of the container and, wherein in a second method step an initial pressure of the compressible medium is measured and, wherein in a third method step, the total volume of the container is changed by a predetermined change volume AV and, wherein in a fourth method step a change in internal pressure of the compressible medium in the container caused by the change in volume is measured, and in a fifth method step the liquid measuring medium is passed through at least one opening of the container Capillary flows, wherein the change internal pressure is measured at least one measurement time and wherein in the second process step, the initial pressure of the liquid measuring medium after exiting the capillary surrounding compressible medium is measured, wherein the measurement of the dynamic viscosity η of the liquid measurement -Mediums done by evaluating the measured data measured by the law of Hagen-Poiseuille.
    In the measuring method according to patent AT 508 276 Bl, therefore, the time At is measured, which requires a certain partial volume AVf of the measuring medium for the flow through the capillary, in order to obtain a value by transforming the law of Hagen-Poiseuille Δ νΔΐ = + 7i * Rk4 * Δρ / (8 * LK * r |) equation η = Δί * RK4 * π * Δρ / (8 * LK * ΔνΡ) to determine the dynamic viscosity η. According to the measuring method according to Patent AT 508 276 B1, two measurement processes are necessary for the determination of the kinematic viscosity v. VjU = + 7t * DK4 * ΙΔρΙ / (128 * LK * r |) + π * ϋκ4 * (p * g * h) * sin (a) / (128 * LK * η) for the measuring medium pressed down with the equation (Δνρ / Δί) Υι0 = - π * ϋκ4 * ΙΔρΙ / (128 * LK * r |) + π * ϋκ4 * (p * g * h) * sin (a) / (128 * LK * η) for the upwardly aspirated measuring medium the equation (ΔνΡ / Δΐ) ν, ιι - (ΔνΡ / Δί) ν, 0 = 2 * π * DK4 * Δρ / (128 * LK * η) to determine the dynamic viscosity and the equation (AVF / At) v! U + (AVF / At) Vi0 = 2 * π * Dk4 * (p * g * h) sin (a) / (128 * Lk * η) is obtained to determine the density and with the aid of the equation v = η / p the kinematic viscosity v is obtained.
    In the known measuring method and the known measuring device has proven to be a disadvantage that the meter must be set up very accurately horizontally with the capillary for measuring the dynamic viscosity horizontally arranged in order to obtain any measurement errors. The dynamic viscosity is determined in that a pressure difference is set on a horizontal capillary, whereas the kinematic viscosity is determined by determining the volumetric flow caused by gravity in a vertical capillary. Consequently, if the known measuring device is not positioned exactly horizontally, then the capillary is also not exactly horizontal, which is why a proportion of the kinematic viscosity is measured when determining the dynamic viscosity, which leads to a measurement error.
    Furthermore, it has proved in the known measuring device as a disadvantage for the measurement of the kinematic viscosity that 1. two successive measurements are necessary, which leads to twice the measuring time and thus also increases the total error of the measurement, 2. Δρ constant and in the two process steps. Pressing "and" sucking "must be exactly the same size, but with opposite sign, which is not feasible, especially with the method with a Δρ that changes with time, 3. depending on the design of the measuring cell for measuring" pressing "or" sucking "Would be cheaper, but in the present method for measuring the kinematic viscosity both steps must be applied.
    The invention has for its object to provide a measuring method according to the type specified in the first paragraph, in which the kinematic viscosity and the dynamic viscosity can be determined with a capillary simultaneously with a single measurement, while also increasing the accuracy of measurement.
    To solve the above-mentioned object is provided in such a measuring method with a measuring device with a capillary in operating position at a certain angle to the horizontal, preferably vertically arranged capillary, that in a first process step, the measuring medium in the filled with a compressible medium, in particular ambient air first Container is introduced, after which the measuring medium fills a partial volume of the total volume of the first container and, wherein in a second method step, a pressure difference between a pressure of the compressible medium in the first container and a pressure of the compressible medium at the outlet opening of the capillary is adjusted and , In a third method step, the volume decrease of the measuring medium per unit time for the pressure difference kept constant or for a decreasing by the decrease in volume of the measuring medium pressure difference is determined by at least two Mes in a final step, the kinematic viscosity of the value of the result line for the volume decrease of the measuring medium per unit time at the pressure difference of Δρ = 0 and the dynamic viscosity of the measuring medium is determined from the slope of the result line.
    The invention is based on the finding that the volume flow of the measuring
    Medium per unit time at constant or decreasing pressure difference at the two ends of the capillary over two or more measuring points results in a result straight line in a coordinate system. Furthermore, a variety of tests and measurements, the knowledge of the invention has enabled the kinematic viscosity at the pressure difference of Δρ = 0 from the value of the result line for the volume decrease of the measuring medium per unit time and that the dynamic viscosity of the measuring medium from the Slope of the result line can be determined by inserting into a formula.
    Due to the features according to the invention it is achieved that both the dynamic viscosity and the kinematic viscosity can be measured simultaneously during a measurement with only one measuring method and only one measuring device. It is particularly advantageous here that the measuring medium only has to be introduced into the measuring device once and both the dynamic and the kinematic viscosity can be displayed after the measuring method has been processed.
    Furthermore, it has proved to be advantageous that the measuring method not only works for capillaries arranged horizontally or vertically in a measuring instrument, but can in principle be used with any capillary angle to the horizontal, since the capillary angle has no influence in this measuring method for calculating the dynamic viscosity and the formula for calculating the kinematic viscosity in the constant K2 is included and can be taken into account when measuring the capillary angle with position sensors.
    The invention will be described below with reference to an embodiment shown in the figures, to which the invention is not limited.
    FIG. 1 shows a measuring device with a vertical capillary for measuring the kinematic and the dynamic viscosity.
    FIG. 2 shows the result straight line determined in a first embodiment variant of the measuring method.
    FIG. 3 shows eleven measuring points of a practical measurement to the first embodiment variant of the measuring method.
    FIG. 4 shows the result straight line determined by the measuring device during the practical measurement according to FIG.
    FIG. 5 shows 32 measuring points of a practical measurement in a second variant of the measuring method.
    FIG. 6 shows how the evaluation device of the measuring device determines the result straight from the measuring points according to FIG.
    FIG. 7 shows the result straight determined by the measuring device during the practical measurement according to FIG.
    1 shows a measuring device 1 according to a first embodiment of the invention for measuring the kinematic and dynamic viscosity of a substantially incompressible measuring medium, which is formed by a liquid F. The measuring device 1 has a first container 2 with a volume Vo, in which a pressure po prevails when the container 2 is empty. Empty here is to be understood that the liquid to be measured F has not yet been introduced into the first container 2, wherein the first container 2 but with a compressible medium, in this embodiment with ambient air or air L, is filled. A computer 3 forms an evaluation device which is connected to a pressure sensor 4 in order to measure the pressure p (t) prevailing in the first container 2 during the different method steps of the measuring method. The computer 3 further forms control means and is connected via a control line with a Peltier element 5, which for stabilizing the temperature of the liquid F and the air L in particular in the first container 2, but also in containers connected thereto, during the execution of the measuring method is trained.
    The measuring device 1 further comprises means of change 6, which are provided for compressing or decompressing the air L in the first container 2 and with which the total volume Vo of the first container 2 is variable by a predetermined change volume AV. The changing means 6 are formed in this embodiment by a servomotor 7, a cylinder with the change volume AV and a displaceable in the cylinder by the servomotor 7 piston 8. The computer 3 is connected via a control line to the servomotor 7 and controls the position of the piston 8 in the cylinder and thus the volume of the first container. 2
    The measuring device 1 further has a second container 9, which is designed to be open at the top, which is why the liquid contained in the second container 9 F is surrounded with air L with the pressure po, which corresponds to the pressure prevailing in the measurement ambient pressure. The computer 3 further has a pressure sensor 10, which measures the current ambient pressure on the housing of the computer 3 before and during the execution of the measuring method.
    Furthermore, the measuring device 1 has a capillary 11 which connects the first container 2 to the second container 9 at a capillary angle α = 90 ° to the horizontal when the measuring device 1 is arranged in the operating position. Through the capillary 11, the liquid contained in the first container 2 F can flow through the force of gravity and / or by a pressure difference Δρ = p (t) - po flow from the first container 2 into the second container 9. If the pressure difference is negative and in terms of magnitude greater than the gravity on the liquid F, then the liquid F can be sucked from the second container 9 in the first container 2. The capillary 11 has a thin flow cross-section Dk, through which the liquid F can flow through an opening 12 of the first container 2 via the capillary 11 and an opening 13 of the capillary 11 into the second container 9.
    In general, the viscosity of a liquid can be determined by measuring the time it takes for an amount of liquid to be under the influence of a driving force to flow through a capillary. A distinction is made between the concept of kinematic viscosity v and the dynamic viscosity η, where the driving force for measuring the kinematic viscosity v represents the dead weight of the liquid to be measured in the gravitational field of the earth, and where the driving force for measuring the dynamic viscosity η is a pressure difference between the dmck is given to the liquid at the beginning and at the end of the capillary. The dynamic viscosity η is the actual measure of the viscosity of the liquid. The time duration At, which requires a certain volume of fluid AVp as a result of the pressure difference Δρ for the passage through a horizontally arranged capillary of length LK and diameter Dk, is related to the dynamic viscosity η of the fluid F in the following context:
    Hagen-Poiseuille law: AVF / At = π * Dk 4 * Δρ / (128 * LK * η)
    According to the first embodiment shown in Figure 1, the second container 9 is executed open at the top, which is why the pressure po in the second container is always equal to the ambient pressure. The mode of operation of the measuring device 1 according to the first exemplary embodiment is described below on the basis of the measuring method processed by the measuring device 1. In the first method step, the liquid F is introduced via an opening, not shown in FIG. 1, of the first container 2 into the first container 2, after which the liquid F to be measured fills a partial volume Vfo of the total volume Vo of the first container 2 and fills with air L. is surrounded by the pressure po, which corresponds to the prevailing ambient pressure during the measurement.
    With one of the operating elements T of the computer 3, after the introduction of the liquid F, the automated measuring method can be started. Thereafter, the computer 3 outputs a control pulse to the servomotor 7 to move the piston 8 in the cylinder by a compression stroke. In this second method step of the measuring method, the total volume Vo of the container 2 is reduced by the predetermined change volume AV. In accordance with this second method step of the measuring method, a pressure difference Ap between the pressure p = p (t) in the first container 2 and a pressure p0 of the air L at the outlet opening 13 of the capillary 11 or in the second container 9 is thus set at a time t , Subsequently, the pressure p caused by the volume change Vo - VFo - AV is measured in the container 2 with the pressure sensor 4 and stored in the computer 3.
    From this time t, the liquid F flows through the capillary 11 depending on the set pressure difference Ap, which is why the pressure p (t) changes over time due to the decrease or increase in the liquid F in the first container 2. In a third method step, the volume decrease VF (t) of the fluid F per time unit t is determined for the pressure difference Ap (t) decreasing as a result of the decrease in volume VF (t) of the fluid F.
    The dependence of the volumes and pressures before and after the compression or during the outflow of the liquid F from the first container 2 over time due to the pressure difference Δρ = p (t) - po between the two capillary ends is governed by the law of Boyle-Mariotte described:
    Po * (Vo - VF0) = p (t) * (V0 - AV - Vfo + VF (t)).
    This results in VF (t) = AV - (Vo - VF0) + (Vo - VF0) * Po / p (t) for the volume of the measuring medium or fluid FF and for the volume flow dVF / dt = (Vo - VF0) * Po * d (l / p (t)) / dt.
    Thus, the volume flow dVi / dt of the measuring medium from the measured decay curve of the pressure p (t) can be determined.
    According to the first embodiment of the measuring method, the liquid F flows driven by the pressure difference Ap (t) and additionally driven by gravity from the first container 2 into the second container 9 until the pressures in the container 2 and in the container 9, taking into account the gravitational pressure p * g * h * sin (a) are in equilibrium. The volume flow dV / dt, which decreases as a result of the decreasing pressure difference Ap (t), is registered according to the invention as a result straight line 14 in a coordinate system, as shown in FIG. The computer 3 determines and stores the result line 14 electronically to evaluate them - as described below.
    In a concluding method step, the result straight line 14 determined from at least two measuring points is used to obtain i = Κι * 1 / η * Api + K2 * 1 / v and (dVF / dt) 2 = by means of the following formulas (dVF / dt) Κι * 1 / η * Ap2 + K2 * 1 / v with the constants ^ = 7 ^ 0 ^ / (128¾) and K2 = 7i * DK4 * g * h * sin (a) / (128 * LK) with LK as Length of the capillary and DK as the diameter of the capillary 11 and the capillary angle α of the capillary 11 to the horizontal to determine the kinematic viscosity v and the dynamic viscosity η. Namely, the relation holds that an offset 15 of the result line 14 to the zero point of the coordinate system as kinematic viscosity v and the slope of the result line 14 as dynamic viscosity η can be evaluated with the above formulas.
    This is done so that from dVp / dt = Κι * 1 / η * Δρ + K2 * l / v (A) with Κι = constant, η = constant, K2 = constant, v = constant by differentiating the volume flow dVF / dt after the differential pressure Δρ d (dVF / dt) / d (Ap) = Κι * 1 / η (B) or I / η = d (dVF / dt) / d (Ap) * 1 / K |, (C) becomes. This means that the reciprocal of the dynamic viscosity η is proportional to the change in the volume flow dVp / dt with the pressure difference Δρ times the proportionality constant 1 / Ki.
    On the other hand, assuming Δρ = 0 in the above equation (Α), we obtain (dVF / dt) Ap = o = K2 * 1 / v (D) and 1 / v = (dV F / dt) Ap = o * l / K2. (E)
    This means that the reciprocal of the kinematic viscosity v is proportional to the volume flow dVF / dt at the point Δρ = 0 times the proportionality constant 1 / K2.
    As a practical example results in the following measurement results and specifications by the measuring device 1 as follows:
    Po = 970 mbar = 97000 Pa V0 = 2000 pL = 2E-6 m3 VF0 = 500 pL = 5E-7 m3 AV = 140 pL = 1, 4E-7 m3
    Dk = 0.3 mm = 0.0003 m Lk = 50 mm = 0.05 m h = 60 mm = 0.06 m a = 90 ° = 1.57 rad
    The measuring medium used was water at 20 ° C., which according to the literature has the following reference values: η = 1 mPas = 0.001 Pas p = 1 g / cm 3 = 1000 kg / m 3 v = 1 mm 2 / s = 1E-06 m 2 / s
    Based on Boyle-Mariotte's law, computer 3 determines: P = PO * (Vo-Vfo) / (Vo-Vfo-AV) = 1069.85 mbar = 106985.29 Pa Ap (t = 0) = p - po = 99.85 mbar = 9985.29 Pa and the constants Kl and K2, which result from the geometry of the measuring device 1: Κι = π * Dk4 / (128 * Lk) = 3.98E-06 mm3 = 3.98E -15 m3 K2 = π * Dk4 * g * h * sin (a) / (128 * Lk) = 2.34E-03 mm5 / s2 = 2.34E-15 m5 / s2
    After opening a valve 16 and the start of the measurement process, the water begins to flow through the capillary 11, whereupon the following measured values are determined by the pressure sensor 4 at measurement times to tio or tio to t3o. The values dVi / dt are determined for the measurement times from dVF / dt = po * (V0-Vfo) * d (l / p (t)) / dt with p (t) = Ap (t) -p0.
    FIGS. 3 and 4 show measured values and the resulting result line 14 of the measuring method according to the first exemplary embodiment with the "push down" with AV> 0 (compression) of the liquid F. FIGS. 5 to 7 show measured values and the result line 14 of the measuring method according to a second exemplary embodiment, in which after the "push down" with AV> 0 (compression) an "upwards suction" with AV <0 (decompression) of the Liquid F is performed.
    Press down: AV> 0 (compression)
    Suck up: AV <0 (decompression)
    FIG. 5 shows the decrease in the pressure difference Ap (t) at the eleven measuring times to to tio and the increase in the pressure difference Ap (t) at the 21 measuring times ti0 to t30 for the combined measuring method for "push downwards" and "pull upwards". , FIG. 6 shows, for individual ones of the 32 measured values in the combined measuring method according to the second exemplary embodiment, how the individual assigned points of the result line 14 are calculated by the evaluation device of the computer 3 from the measured values by using the above formulas. FIG. 7 shows the result line 14 determined according to FIG. 6 in a representation comparable to FIG. The resulting values for the liquid F water are as follows: dynamic viscosity η = 1 / (1 / η) = 1 / (d (dVF / dt) / d (Ap) * 1 / Ki) = 1 / (3.976 E-12 * 1 / 3.98E-15) = 0.001 Pas kinematic viscosity v = 1 / (l / v) = 1 / ((dVF / dt) Ap = o * 1 / K2) = 1 / (2.340E- 09 * 1 / 2,34E-15) = 1E-6 m2 / s.
    In practice, the constants Ki and K2 are not obtained from the geometrical details of a measuring device as in the above example, since e.g. Even the measurement of a capillary diameter DK of 0.5 mm with sufficient accuracy would not be possible with justifiable effort. Therefore, the constants are obtained by a Justiermessung with a reference measuring medium by the formulas for the calculation of the dynamic viscosity (C) and the kinematic viscosity (E) for the calculation of Ki or K2 be transformed: 1 / Ki = d (dVF / dt) / d (Ap) * 1 / η, (C ') or 1 / K2 = (dVF / dt) Ap ο * l / v, (E)
    Since the values of the dynamic viscosity η and the kinematic viscosity v of the reference measuring medium are very accurately known, the values for Ki and K2 can be calculated by evaluating the result straight line.
    The measuring method according to the invention and the measuring device have the following advantages: 1. The kinematic viscosity and the dynamic viscosity can be determined simultaneously with a capillary with only a single measurement. 2. The measurement method with a time-varying Δρ (due to changing internal pressure) is applicable for the simultaneous determination of the dynamic viscosity and the kinematic viscosity, with the additional advantage that the accuracy can be improved by evaluating the linear equation with modern algorithms such as linear Regression is significantly increased. 3. An estimate of the quality of each individual measurement is possible by comparing the measured curve with an exact line passing through the measurement points. The closer the points are to the result line 14, the better the quality of the measurement. Even filling errors, such as air bubbles in the measuring medium, are so recognizable. An adequate estimation would otherwise only be possible by comparison with a second measurement of the same measuring medium. 4. The capillary does not have to lie exactly horizontally, as in the measuring method according to patent AT 508 276 Bl, in order to precisely determine the dynamic viscosity, since it is no longer the time for the outflow which, in the case of non-horizontal capillaries, is determined as a result of Measuring medium medium acting gravity would change, but the dynamic viscosity resulting from the slope of the straight line, which is independent of the angle of the capillary to the horizontal. 5. Measurements with at least two arbitrary, constant pressures Ap would also be possible by constructing a result straight from the at least two measurement points. 6. To increase the measuring accuracy, several consecutively performed measurements of the same measuring medium can be evaluated together via the straight-line equation in order to further increase the accuracy of the measurement.
    According to another embodiment, not shown in the figures, a measuring device on pressure fixing means to keep a first pressure pi in the first container even when running through the capillary liquid constant. The first pressure pi is thus determined by the computer and remains constant during the execution of the measurement process in the first container. Subsequently, a second measurement is carried out with a second pressure p2 kept constant in the first container in order to be able to determine the result straight with these two measured values. Also according to this exemplary embodiment of the measuring method, by evaluating the result line, the kinematic viscosity v and the dynamic viscosity η of the fluid F can be determined by the computer 3 during execution of the measuring method in the measuring device 1.
    According to this further exemplary embodiment, the second container also has liquid level measuring means, which are formed by two NTC resistors and evaluation means in the computer. The NTC resistors are electrically heated and undergo cooling by the liquid passing the inside of the second container, with the NTC resistors cooling differently depending on whether liquid or vapor passes past the inside of the second container. In this way, the computer can measure the outflow of a certain amount of liquid λVf from the first container into the second container, which is necessary only in the measurements with the first pressure pi kept constant or the second pressure p2 kept constant.
    According to a further embodiment, a second measuring device, not shown in the figures, instead of the upwardly open container 9 has a closed second container in which the pressure in the second container changes due to the incoming or outgoing liquid F, which change is measured by a pressure sensor becomes.
    The second measuring device with the closed containers has the advantage that air pressure fluctuations with respect to the ambient pressure po in the room or outdoor area where the measuring device is located, can not have a disturbing influence on the measurement. This advantage is particularly useful for high-precision measurements or in harsh environments. It is particularly advantageous here to use a differential pressure sensor for measuring the pressure difference between the pressure in the first container and the pressure in the second container.
    It can be mentioned that the result straight can be determined in the case of very different variants of pressure differences between the first container and the outlet opening of the capillaries. In order to determine the result line, at least two measuring points must be determined, with the result that the better the quality of the result, the more measuring points can be determined.
    According to a further embodiment of the invention, the capillary has a capillary angle α of 45 or 60 degrees. Since advantageously the capillary angle in the above formulas for determining the dynamic and kinematic viscosity from the result line is measured and taken into account mathematically, accurate and correct values for the dynamic and kinematic viscosity of the measuring medium are also obtained with these measurements with measuring devices.
    权利要求:
    Claims (3)
    [1]
    claims:
    1. Measuring method for measuring the viscosity of a substantially incompressible measuring medium (F) with a first container (2) having measuring device (1), wherein from the first container (2) the measuring medium (F) via an in Operating position in a certain capillary angle (a) to the horizontal, preferably perpendicularly arranged capillary (11) via an outlet (13) of the capillary (11) can run out and, in a first process step, the measuring medium (F) in the with a compressible Medium (L), in particular ambient air-filled first container (2) is introduced, after which the measuring medium (F) fills a partial volume (Vfo) of the total volume (Vo) of the first container (2) and, wherein in a second process step, a pressure difference (Δρ; Ap (t)) between a pressure (p; p (t)) of the compressible medium (L) in the first container (2) and a pressure (po) of the compressible medium (L) at the outlet opening (13) the capillary (11) is set and, wherein in a third method step, the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit time for the pressure difference kept constant (Δρ) or for a by the volume decrease (dVF (t) / dt) of the measuring medium (F) decreasing pressure difference (Ap (t)) is determined by at least two measuring points of the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit time over the pressure difference (Δρ) as the result straight line ( 14) in a coordinate system and, wherein in a final method step, the kinematic viscosity (v) from the value (15) of the result line (14) for the volume decrease (dVF (t) / dt) of the measuring medium (F) each Time unit at the pressure difference of Δρ = 0 and the dynamic viscosity (η) of the measuring medium (F) from the slope of the result line (14) is determined.
    [2]
    2. Measuring method according to claim 1, characterized in that the volume decrease (dVF (t) / dt) of the measuring medium (F) per unit time for a by the volume decrease (dVF (t) / dt) of the measuring medium (F) decreasing pressure difference (Δρ (ί)) is determined by the following formula from the measured decreasing pressure difference over time: dVF (t) / dt = (V0-VF0) * po * d (l / p (t)) / dt, where p (t) Ap (t) = p (t) - po, and from this the following result line (14) is determined from any number of measuring points: (d Vdt) = Κι * 1 / η * Δρ + K2 * 1 / v with the constants Κι = π * ϋκ4 / (128 * Lk) and K2 = π * ϋκ4 * (g * h) * sin (a) / (128 * LK) with LK as the length of the capillary (II) and DK as the diameter the capillary (ll) and the capillary angle (a) of the capillary (11) to the horizontal in order to determine the kinematic viscosity (v) and the dynamic viscosity (η) of the measuring medium (F) in the final method step.
    [3]
    3. Measuring method according to claim 1, characterized in that in the third method step kept constant first pressure difference (Api) for determining the first measuring point, a first measuring time is determined, during which the entire measuring medium (F) or a measured part thereof from the in the third method step for determining the second measuring point, a second pressure difference (Ap2) different from the first pressure difference (Api) between the pressure (p) of the compressible medium (FIG. L) in the first container (2) and the pressure (po) of compressible medium (L) at the outlet opening (13) of the capillaries (11) or in an open second container provided at the outlet opening (13) of the capillaries (11) (9) is set and held constant during a second measuring period and a second measuring time is determined during which the entire measuring medium (F) or a measured part dav from the two measuring points of the volume decrease ((dVp (t) / dt) i) at the first pressure difference (Api) or the volume decrease ((dVp (t ) / dt) 2) at the second pressure difference (Ap2) with (dVF / dt) i = Κι * 1 / η * Api + K2 * 1 / v and (dVF / dt) 2 = Κι * 1 / η * Ap2 + K2 * 1 / v with the constants ^ = 71 * 0 ^ / (128 * 1 ^) and K2 = Ti * DK4 * (g * h) * sin (a) / (128 * LK) with Lk as the length of the capillary (11) and DK as the diameter of the capillary (11) and the capillary angle (a) of the capillary (11) to the horizontal a result line (14) is determined in order to determine in the final step, the kinematic viscosity (v) and the dynamic viscosity ( η) of the measuring medium (F).
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    同族专利:
    公开号 | 公开日
    EP3348991A1|2018-07-18|
    US10613009B2|2020-04-07|
    AT518658B1|2017-12-15|
    EP3348991B1|2019-10-16|
    US20180195943A1|2018-07-12|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50014/2017A|AT518658B1|2017-01-12|2017-01-12|Viscometer for determination of dynamic and kinematic viscosity|ATA50014/2017A| AT518658B1|2017-01-12|2017-01-12|Viscometer for determination of dynamic and kinematic viscosity|
    EP18150614.8A| EP3348991B1|2017-01-12|2018-01-08|Method for measuring dynamic and kinematic viscosity|
    US15/867,192| US10613009B2|2017-01-12|2018-01-10|Viscometer for determining dynamic and kinematic viscosities|
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