KR101412629B1 - Device for measuring viscosity - Google Patents

Abstract

Disclosed is a viscosity measurement device comprising a first container for receiving fluid to measure the viscosity; a light source arranged in one side of the first container to measure the viscosity of the fluid using absorbance, and irradiating light toward the fluid; a dropped body submerged in the fluid and passing the light when a user measures the viscosity of the fluid; a detector arranged in the other side of the first container to detect the variation of the absorbance generated by the dropped object, and detecting the light penetrating the fluid; and a second container inserted in the first container, having a holding part formed to hold the dropped object received in the first container, and lifting up the dropped object held on the holding part to enable repetitive measurements when moving upward. Especially, the viscosity measurement device enable repetitive experiments and can perform the measurement in a limited space; thereby measuring the viscosity of special specimens, such as a radioactive substance.

Description

{DEVICE FOR MEASURING VISCOSITY}

The present invention relates to an apparatus for measuring the viscosity of a fluid using a drop method.

Generally, one of four methods is used to measure the viscosity of a fluid: a vibration method, a rotation method, a capillary method, and a drop method. Since each method has advantages and disadvantages, the best method should be selected in terms of the characteristics of the sample to be measured and the overall analysis system.

In particular, when analyzing specimens under special circumstances dealing with high temperature molten salt, high pressure fluid, etc., various environmental factors must be taken into consideration, so it is necessary to carefully examine the applicability to the above four methods.

Of the four methods of viscosity measurement, the drop method is inexpensive and simple compared to other methods, so there are many advantages in installing and using the device in a glove box for high temperature fluids.

In the conventional drop method, a drop is calculated from the Stokes equation by measuring drop time and drop distance using a drop type sphere. However, the conventional method has various complex influences such as the wall effect between the dropping body and the container wall surface, the range of the Reynolds number, the accuracy of the drop body radius measurement, the drop time and the accuracy of the fall distance, And there was a problem that repeated experiments were difficult.

An object of the present invention is to provide a viscosity measuring device capable of accurate measurement and repeated experiment.

Another object of the present invention is to provide a viscosity measuring device capable of accurately measuring the viscosity of a fluid even in a limited environment of high temperature and high pressure.

In order to accomplish the object of the present invention, a viscosity measuring apparatus according to an embodiment of the present invention includes a first container for receiving a fluid to be measured for viscosity, a second container for measuring viscosity of the fluid using the absorbance, A light source that is disposed on one side of the first container and irradiates light toward the fluid, a dropping body that sinks in the fluid when the viscosity of the fluid is measured and passes through the light, a change in absorbance generated by the dropping body is detected A detector disposed on the other side of the first container so as to detect light transmitted through the fluid and a latch portion inserted into the first container and internally housed in the drop body, And a second container for lifting up the drop body caught by the catch portion when moved in an upward direction.

According to one example of the present invention, the drop body is formed in a shape of a cylinder or quadrangular column so as to reduce scattering of the light while passing through the light.

According to another example of the present invention, the first container and the second container are formed so that the surface facing the light source and the detector is flattened so as to reduce scattering of light, And a shape corresponding to the container and the second container.

According to another embodiment of the present invention, the second container is formed to be heavier than the weight of the drop body so as to drop earlier than the drop body when the viscosity of the fluid is measured.

According to another example of the present invention, the second container is at least partially opened to allow the fluid to pass while the second container is falling or lifting the drop body.

According to another embodiment of the present invention, the latching portion is formed in such a manner that the cross-sectional area gradually decreases toward the lower end of the second container.

According to another embodiment of the present invention, the drop body is formed of transparent quartz or alumina (Al ₂ O ₃ ) so as to reduce the influence on the transmittance of light and to be free from the corrosivity of the fluid.

According to another embodiment of the present invention, the viscosity measuring device comprises a globe of an argon atmosphere equipped with an electric furnace to measure the viscosity of the fluid at a high temperature without being contacted with atmospheric oxygen and water vapor affecting the viscosity measurement of the fluid, It is installed inside the box.

According to the present invention having the above-described structure, since the drop body can be returned to the initial position before dropping using the second container, the drop can be dropped again to measure the viscosity repeatedly. The viscosity of the fluid can be measured more accurately by obtaining the average value of the viscosity calculated by the repeated experiment.

Further, since the present invention can be installed in a glove box of high temperature and high pressure in a simple configuration, it is possible to measure the viscosity of a special sample affected by the atmospheric environment.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual diagram showing a viscosity measuring apparatus according to an embodiment of the present invention. Fig.
2 is a conceptual view showing a process of measuring the viscosity of a fluid using the viscosity measuring apparatus shown in FIG.
Fig. 3 is a conceptual diagram showing that the apparatus for measuring the viscosity of fluid shown in Fig. 1 is installed in a glove box. Fig.
4 is a conceptual view showing a viscosity measuring apparatus according to another embodiment of the present invention.
5A to 5D are bottom views of a second container showing various modifications of the latching portion of the present invention.
6 is a graph showing the intensity of a light source repeatedly measured using a viscosity standard material.
7 is a graph showing a correlation between viscosity and time measured repeatedly using a viscosity standard material.
8 is a graph showing a calibration line for obtaining a device constant K using a viscosity standard material.
9 is a graph showing the result of repeated measurement of a molten salt drop time at a high temperature.

Hereinafter, a viscosity measuring apparatus according to the present invention will be described in detail with reference to the drawings. In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

1 is a conceptual diagram showing a viscosity measuring apparatus 100 according to an embodiment of the present invention.

The viscosity measuring apparatus 100 using the falling method measures the viscosity of the fluid by dropping the drop 130 into the fluid and observing the change in absorbance while passing the light irradiated to the fluid from the light source 140. The viscosity measuring apparatus 100 includes a first container 110, a second container 120, a drop body 130, a light source 140, and a detector 150.

The first container 110 receives the fluid for which the viscosity is to be measured. The fluid flows from the second container 120 and the drop 130 to the second container 120 to prevent the sample from overflowing from the first container 110 because the level of the fluid increases due to the volume of the second container 120 when the second container 120 is inserted. It is preferable to set the water level in consideration of the volume of the water.

The second container 120 is inserted into the first container 110. The second container 120 is preferably longer than the first container 110 for extraction from the first container 110 as shown in the figure.

The second container 120 is provided with a latching portion 121 formed to be able to latch so as to prevent the drop body 130 received therein from escaping. As shown in the drawing, the engaging portion 121 may be formed with a gradually decreasing sectional area toward the lower end of the second container 120. However, the shape of the latching part 121 is not limited to this. When the dropping body 130 is formed so as not to be detached from the inside of the second container 120, the shape of the latching part 121 is not limited.

The second container (120) is formed with a hole by the engaging portion (121). Since the cross-sectional area of the hole is smaller than the cross-sectional area of the drop body 130, the drop body 130 does not escape to the outside through the hole, but the fluid can pass through the second container 120 through the hole.

The first container 110 and the second container 120 are preferably formed of a transparent material so as to reduce the influence on the transmittance of light. In addition, when measuring the viscosity of a fluid that is highly corrosive to metallic materials such as chlorine (Cl), it must be able to withstand corrosion. The first vessel 110 and the second vessel 120 may be formed of, for example, quartz or alumina (Al ₂ O ₃ ), which can increase the accuracy of the viscosity measurement.

The drop body (130) is disposed inside the second container (120). In the present invention, the drop body 130 may be formed in a shape corresponding to the shape of the container so as to reduce scattering of light irradiated from the light source 140. For example, when the first container 110 and the second container 120 are formed in the shape of a cylinder, the drop body 130 may be formed in a cylindrical shape. The drop 130 used in the conventional dropping method uses spheres. However, since the distance between the spherical surface and the wall surface of the second container 120 is not constant, scattering of the light emitted from the light source 140 is caused. Thus, the intensity of the detectable light in the detector 150 may not be obtained, which reduces the accuracy of the viscosity measurement. In particular, when the fluid to be measured is opaque, the transparency of light is lowered, so that the light transmitted through the fluid may not be detected properly. Therefore, when the drop body 130 is formed in a cylindrical shape corresponding to the shape of the container, and the distance between the second container 120 and the drop body 130 is kept constant, the light emitted from the light source 140 Since the light scattering can be reduced, the accuracy of the viscosity measurement can be increased.

The drop 130 should have a specific gravity larger than that of the fluid to be measured and should settle down in the fluid, have heat resistance when used at high temperature, and should not affect the corrosiveness of the fluid. When the drop 130 is formed of transparent quartz or alumina (Al ₂ O ₃ ), it is resistant to chemical attack by the fluid because it has a characteristic of corrosion resistance and reduces the influence on the light transmittance . Since alumina (Al ₂ O ₃ ) has a larger specific gravity than quartz, when the specific gravity of the fluid to be measured is larger than quartz, alumina should be used so that the drop body 130 can sink into the fluid.

When the viscosity of the fluid is measured, when the second container 120 is freely dropped, the drop 130 inside the second container 120 is also dropped. Since the weight of the second container 120 is larger than the weight of the drop 130, the drop 120 is dropped earlier than the drop 130 and the drop 130 drops more slowly than the second 120.

The viscosity measuring apparatus 100 using the falling method measures the viscosity of the fluid using the absorbance of the fluid, so that the light source 140 and the detector 150 are disposed on one side and the other side of the first container 110, respectively.

The light source 140 irradiates light of a predetermined intensity toward the fluid contained in the first container 110. Since the viscosity measuring apparatus 100 measures the change in absorbance by the fluid, accurate measurement is difficult unless the intensity of the light emitted from the light source 140 is constant.

Detector 150 is disposed across light source 140 to detect light that has passed through the fluid. If the fluid is opaque or if the thickness of the fluid filled in the first container 110 is large, the light transmittance is low. Therefore, it is necessary to increase the intensity of the light emitted from the light source 140 or to maintain the frost between the dropping body 130 and the second container 120 as close as possible, Light must be transmitted.

2 is a conceptual diagram showing a process of measuring the viscosity of a fluid using the viscosity measuring apparatus 100 shown in FIG.

In the initial state in which the measurement is started, the fluid to be measured is contained in the first container 110, and the drop 130 is positioned below the surface of the fluid in the state of being disposed inside the second container 120 . The second container 120 is disposed at least partially in the fluid as the drop body 130 is locked below the water surface. The light source 140 irradiates light toward the fluid at one side of the first container 110 and the detector 150 continuously detects light passing through the fluid at the other side of the first container 110.

The viscosity measurement of the fluid begins with free fall of the second vessel 120. When the second container 120 and the drop 130 drop simultaneously, the droplet 130 can be accurately measured by the second container 120. In this case, It becomes difficult to accurately measure the viscosity of the fluid. Therefore, even if the weight of the second container 120 is made heavier than the weight of the dropping body 130, even if the second container 120 and the dropping body 130 are dropped simultaneously, the second dropping body 130 is dropped first, The movement of the fluid caused by the drop of the second container 120 is stabilized before the body 130 passes the light irradiated from the light source 140, so that accurate measurement can be induced.

The weight of the second drop 130 drops earlier than the drop 130, and then the drop 130 drops in the fluid. Since the positions of the light source 140 and the detector 150 are fixed, light is irradiated toward a fixed portion of the fluid, and the drop body 130 passes light irradiated to the fluid. The drop rate can be measured by measuring the change of the absorbance while the drop body 130 passes light.

When the viscosity of the fluid is measured by using the falling method, the Stokes equation described in the following equation (1) is used. μ is the viscosity of the fluid, r is the radius of the drop body 130, g is the gravitational acceleration, ρA is the density of the drop body 130, ρB is the density of the fluid, t is the dropping time due to free fall, L Indicates the falling distance.

However, the Stoch equation can be established only when it satisfies various assumptions strictly. In other words, the falling object must be a perfect spherical surface with a smooth surface and no deformation, and the fluid must have a uniform composition with no change in density, and in the free flow with no steady state wall effect, The Reynolds number is established only in the laminar flow of the low continuum. Therefore, in order to correct the wall effect for the drop body 130 which is not a spherical shape as in the present invention, Equation (2) introducing a shape factor s and a Faxen correction factor f is used.

When the second container 120 and the drop body 130 are completely dropped and the second container 120 is lifted to the initial position, the drop body 130 caught by the catch portion 121 also returns to the initial position . The viscosity measuring apparatus 100 can return the drop body 130 to the initial position by using the second container 120. Therefore, the viscosity of the fluid can be repeatedly measured, and the average value is obtained by summing the repeated measurement results A more accurate viscosity can be obtained.

The fluid passes through the groove formed at the lower end of the second container 120 while lifting the second container 120 to return the drop body 130 to the initial position before the drop. Thereby, there is no change in the total amount of the fluid before and after the dropping of the second container 120 and the dropping body 130 and returning to the initial position.

Fig. 3 is a conceptual diagram showing that the apparatus for measuring the viscosity of fluid 100 shown in Fig. 1 is installed in the glove box 10. Fig.

The glove box 10 is a box that can be operated by the globe 11 to prevent the influence of the viscosity measuring process on the external environment. The glove box 10 is an argon atmosphere, which is airtight so that it is not in contact with atmospheric oxygen and water vapor, which influences the viscosity measurement of the fluid, and the inside is an inert gas.

An electric furnace 12 is mounted inside the glove box 10 to measure the viscosity of the fluid at a high temperature and light emitted from the light source 140 is directed toward the detector 150 on both sides of the electric furnace 12 The window 13 may be formed to pass through. The window 13 may be formed of transparent quartz or alumina (Al ₂ O ₃ ) to prevent the light transmittance from being lowered.

The viscosity measuring apparatus 100 can be installed in a limited space such as the glove box 10 because a large installation space is not required. It is also possible to drop the second container 120 through the globe 11 in the glove box 10 and return to the initial position before dropping again so that the viscosity of the fluid can be accurately measured Can be measured.

4 is a conceptual diagram showing a viscosity measuring apparatus 200 according to another embodiment of the present invention.

The viscosity measuring apparatus 200 includes a first container 210, a second container 220, a dropping body 230, a light source 240, and a detector 250 in the same manner as the viscosity measuring apparatus 100 shown in FIG. . Light irradiated from the light source 240 toward the fluid can cause scattering on the respective surfaces due to the shapes of the first container 210, the second container 220, and the drop body 230.

The first container 210 and the second container 220 are formed with a flat surface facing the light source 240 and the detector 250 so as to reduce light scattering. The dropping body 230 is formed in a shape corresponding to the first container 210 and the second container 220. Accordingly, the surface of the drop body 230 facing the light source 240 and the detector 250 can also be formed flat, and light scattering can be reduced. If the scattering of light is reduced, the intensity of light that can be detected by the detector 250 can be satisfied, and the accuracy of the viscosity measurement can be increased.

5A to 5D are bottom views of second containers 320a, 320b, 320c and 320d showing various modifications of the latching parts 321a, 321b, 321c and 321d of the present invention.

The bottom view of the second container 320a shown in FIG. 5a is the same as the second container 120 shown in FIG. The engaging portion 321a is formed so that the cross-sectional area of the engaging portion 321a becomes gradually narrower toward the lower end of the second container 320a, and the middle portion thereof is opened to allow the fluid to pass therethrough. Since the fluid having a strong viscosity is difficult to pass through the second container 320a, the second container 320a should be opened to the maximum extent within a range that does not release the drop body. In particular, if the fluid can not pass through the second container 320a while the second container 320a falls down in the first container, it is difficult to accurately measure the fluid because the fluid is affected by the movement of the fluid during the drop.

5B to 5D illustrate an improvement of this point. The latching portion 321b shown in FIG. 5B is formed such that the second container 320b can be opened in a cross shape, and the latching portion 321c shown in FIG. Is formed such that the second container 320c can be opened in a straight line. The latching portion 321d shown in FIG. 5D is formed in a straight shape connecting both side walls of the second container 320d, and is formed so that the fluid can pass through the opened portions on both sides.

Hereinafter, it is verified that accurate measurement is made by measuring the viscosity of a fluid using the viscosity measuring apparatus disclosed in the present invention through the examples.

In Example 1, the relationship between the viscosity (μ) and the dropping time (t) of the drop body is verified by using a viscosity standard material. The verification of the viscosity measurement does not use Equation (2) as it is, but uses Equation (3) below.

K in the equation (3) is an apparatus constant, and is an arbitrary constant including all the remainders except for (ρ _A -ρ _B ) t described on the right side of the equation (2). Here, since the density ρ _A of the drop body and the density ρ _B of the fluid can be known here, the viscosity μ is treated as a constant, and the relation of the viscosity μ with the time t is obtained.

5, 7.5, 10, 15, 20, and 50 cP, the falling time of the drop body was measured repeatedly using the viscosity measuring apparatus proposed in the present invention. As shown in FIG. 1, the first container proposed in the present invention is filled with a viscosity reference material, and then the time t of the drop body passing through the light source is measured repeatedly using the second container. Since the viscosity μ is proportional to the time t as described in the formula (3), in the first embodiment, the time t during which the drop body passes the light source is measured to confirm the correlation with the viscosity μ.

6 is a graph showing the intensity of a light source repeatedly measured using a viscosity standard material. The intensity of the light source in FIG. 6 indicates the change in absorbance. After the drop body passes the region of the light source as shown in FIG. 2, the light intensity decreases and the drop body completely passes through the region of the light source, Is returned to its original state. The time t was determined by measuring the time that the intensity of the light source returns and decreases again.

Table 1 shows the values of the time t obtained by repeatedly measuring the fall time of the drop body using the viscosity measuring apparatus proposed by the present invention for each viscosity standard material.

Number of measurements time 5cP 7.5 cP 10 cP 15 cP 20 cP 50 cP One 0.39 0.67 0.83 1.11 1.65 4.96 2 0.38 0.68 0.83 1.12 1.83 4.99 3 0.42 0.63 0.79 1.24 1.61 4.72 4 0.39 0.65 0.83 1.22 1.68 4.57 5 0.39 0.66 0.79 1.24 1.63 5.04 6 0.38 0.68 0.83 1.21 1.59 3.43 7 0.37 0.63 0.80 1.30 1.61 4.78 8 0.42 0.67 0.80 0.97 1.51 4.11 Average 0.39 0.66 0.81 1.18 1.64 4.64 Standard Deviation 0.02 0.02 0.02 0.10 0.09 0.55

7 is a graph showing the correlation between the time and the viscosity measured repeatedly using the viscosity standard material. It can be seen that the viscosity can be calculated by measuring only the dropping time t since the linearity of the coefficient of determination R ² indicating the linearity of the graph is 0.997.

The viscosity measuring apparatus proposed in the present invention is a device capable of measuring the viscosity of a fluid at a high temperature of 400 ° C or higher, and in Example 2, the experiment was conducted at 500 ° C. The viscosity of the fluid was measured in a glove box under high temperature conditions as shown in FIG. 3, and a high purity eutectic mixture of 99.99 ° C. was used to evaluate the accuracy of the viscosity measurement.

8 is a graph showing a correction line for obtaining a device constant K using a viscosity standard material. 8 is a graph showing the relation between the density (ρ _A ) of a drop, the density (ρ _B ) and the drop time (t) of a drop, using a viscosity standard material in Example 1, K) was obtained.

9 is a graph showing the result of repeated measurement of the molten salt falling time at a high temperature.

The falling time (t) was determined by repeated measurement using the viscosity measuring apparatus proposed in the present invention, and a pure lithium chloride / potassium chloride viscosity value 2.5 ± 0.3 cP was obtained as a result of using the already obtained apparatus constant (K). It is known that the viscosity of pure lithium chloride / potassium chloride is already known, and almost coincides with the predicted value within the error range. Therefore, it can be seen that the viscosity of the fluid can be accurately determined by simple measurement even at high temperature and high pressure. have.

The viscosity measuring apparatus described above is not limited to the configurations and the methods of the embodiments described above, but all or a part of the embodiments may be selectively combined so that various modifications can be made in the embodiments.

Claims (8)

A first container for containing a fluid to be measured for viscosity;
A light source disposed at one side of the first container for measuring the viscosity of the fluid using the absorbance and irradiating light toward the fluid;
A dropping body that sinks in the fluid when the viscosity of the fluid is measured and passes through the light;
A detector disposed on the other side of the first container and detecting light transmitted through the fluid to detect a change in absorbance generated by the dropping body; And
And a second container which is inserted into the first container and has a latching portion which is capable of latching the dropping body accommodated therein and lifting up the dropping body which is caught by the latching portion when moving upward so as to enable repeated measurement And a viscosity measuring device. The method according to claim 1,
Wherein the drop body is formed in a cylindrical or square pillar shape so as to reduce scattering of light while passing through the light. The method according to claim 1,
Wherein the first container and the second container have flat surfaces facing the light source and the detector so as to reduce scattering of light,
Wherein the drop body is formed in a shape corresponding to the first container or the second container. The method according to claim 1,
Wherein the second container is heavier than the weight of the drop body so that the second container falls before the drop body when the viscosity of the fluid is measured. The method according to claim 1,
Wherein the second container is at least partially opened to allow the fluid to pass while the second container is falling or lifting the drop body. The method according to claim 1,
Wherein the engaging portion is formed so that a cross-sectional area thereof becomes gradually narrower toward a lower end of the second container. The method according to claim 1,
Wherein the drop body is formed of transparent quartz or alumina (Al ₂ O ₃ ) so as to reduce the influence on the transmittance of the light and not to be affected by the corrosiveness of the fluid. 8. The method according to any one of claims 1 to 7,
Is installed inside a glove box of an argon atmosphere equipped with an electric furnace so as to measure the viscosity of the fluid at a high temperature without being in contact with atmospheric oxygen and water vapor affecting the viscosity measurement of the fluid.

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