JPH0611432A - Method and device for measuring viscosity of liquid under agitation - Google Patents

Abstract

PURPOSE:To provide a method and a device for measuring the viscosity of a liquid specimen while it is being agitated. CONSTITUTION:An inner and an outer cylinder 1, 2 are provided so as to be rotatable, and a narrow part 13a is formed in a part of the ring-shaped space 13 generated between the two cylinders. Upon putting a liquid specimen to be measured in this ring-shaped space 13, the two cylinders are rotated at different speeds. The specimen is agitated while passing through the narrow part, and meantime the viscosity is determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the viscosity of a liquid while stirring the liquid, and more particularly to a device for measuring the viscosity of the liquid. The present invention relates to a method and a device for directly measuring the viscosity of a liquid during stirring and dispersion, while reproducing the above.

[0002]

2. Description of the Related Art Conventionally, various viscosity measuring devices have been proposed, and a rotary viscometer is known as one of them. The rotational viscometer is a non-Newtonian fluid that utilizes the fact that when an object such as a cylinder, a disk, or a sphere is rotated in a fluid, the object receives a torque due to the viscous resistance of the fluid. It is also used to determine the flow curve of.

However, it is mainly the shear viscosity that can be directly measured by this rotational viscometer, and among the liquids, for example, the printing ink acts on the dampening water as it passes through each printing unit of the printing machine. Is dispersed or emulsified, and in the actual printing operation, although the dispersion and the viscosity at the time of emulsification are important factors, the conventional rotational viscometer causes separation of water during measurement and the like It was difficult to accurately determine the viscosity.

That is, the printing ink for lithographic printing forms a resin base having the same degree of stickiness as a varnish, and this base is used.
It is manufactured by adding the soot into the vehicle and kneading with the pigment. During the printing process, this printing ink acts on the fountain solution that is typical of lithographic printing and offset printing to cause dispersion and emulsification. Above all, when the viscosity decreases due to this dispersion and emulsification, the degree of transfer of the printing ink deteriorates. , A good ink film print cannot be obtained.

By the way, with the conventional rotational viscometer,
When measuring the viscosity of the dispersed and emulsified printing ink, a sample of the printing ink is dispersed and emulsified by applying a stirrer.
This will be sampled and measured with a rotational viscometer.

[0006]

However, in the case of performing the measurement as described above, when the dispersed and emulsified sample is sampled and measured by the conventional rotational viscometer,
Since the sample is measured while sampling it one by one, the measurement takes time and continuous measurement is impossible.

The present invention aims to solve the above-mentioned drawbacks. Specifically, a liquid capable of stirring, for example, dispersing or emulsifying a liquid such as a printing ink, and simultaneously measuring the viscosity of the liquid in a stirring state. We propose a method for measuring the viscosity of lactic acid and its apparatus.

[0008]

In order to achieve this object, the method of the present invention forms a narrow portion in a part of an annular space formed between rotating inner and outer cylinders, and the annular space is measured. After putting the liquid to be added, the inner and outer cylinders are rotated with different speeds, respectively, while stirring the liquid in the narrow portion of the annular space,
At this time, the torque or rotational driving force of either the inner or outer cylinder is measured, and the viscosity of the fluid is detected from this measured value.

The best apparatus for carrying out this method is based on the double cylinder type structure shown in FIG. That is, in FIG. 1, reference numeral 1 is an inner cylinder, 2 is an outer cylinder, and the inner and outer cylinders 1 and 2 are both rotatable.
Inside the cylindrical outer cylinder 2, there is a difference in speed, and the cylindrical inner cylinder 1
To store. The rotation axis of the inner cylinder 1 is not arranged coaxially with the rotation axis of the outer cylinder 2, but is arranged in parallel with a space therebetween. Further, this spacing is configured to be controllable or adjustable, and further, the inner cylinder 1 and the outer cylinder 2 are configured to be rotatable by independent speed control mechanisms.
The speed difference between the inner and outer cylinders 1 and 2 is usually provided by rotation in the same direction, but may be provided by rotation in different directions or rotation in only one direction as necessary.

Further, the outer surface of the inner cylinder 1 is provided with a spiral groove oriented in a direction in which a downward force is exerted at the time of rotation by, for example, grooving or the like, so that the slope of the slope is raised by the entrainment of the fluid at the time of rotation. Even viscoelastic fluids that are easy to measure should be able to be easily measured.

Further, in order to quantitatively supply the liquid to the annular space between the inner and outer cylinders 1 and 2, a liquid supply device is provided so that the viscosity can be continuously measured while changing the mixing ratio of the liquid. To do.

[0012]

In the present invention, as described above, since the inner cylinder 1 and the outer cylinder 2 rotate with a predetermined speed difference, the torque due to the viscosity of the liquid acts on the inner cylinder 1 which acts as a liquid stirring section. To do. Further, the rotation axis of the inner cylinder 1 and the rotation axis of the outer cylinder 2 are not coaxial but are parallel and eccentric. Further, at least a part of the annular recess 13 formed between the inner and outer cylinders has a narrow portion 13
Since a is formed, a high shear is applied to the liquid passing through the narrow portion 13a, whereby the sample can be effectively stirred.

That is, according to the present invention, firstly, the viscosity is measured while performing operations such as emulsification of a liquid sample. At this time, since the rotation axis of the inner cylinder 1 is eccentric with respect to the rotation axis of the outer cylinder 2 to form a narrow portion, the stirring efficiency of the liquid sample is increased,
The liquid sample is well agitated. More specifically,
After the liquid sample flows into the narrow portion 13a and passes through the narrow portion 13a, the liquid sample is stretched between the surfaces of the inner and outer cylinders, and the measured torque is affected by the extensional viscosity in addition to the shear viscosity. . This state is equivalent to a state in which the printing ink is spread after passing through the roll-roll nip (contact portion between rolls) in an actual printing unit. It can be measured by passing through the narrow portion 13a. Furthermore, since there is a difference in rotational speed between the inner and outer cylinders 1 and 2, the effect of stretching (stretching) the sample is amplified.

Further, since all the liquid sample passes through the narrow portion 13a where high shear occurs without causing stagnation, the stirring becomes uniform. At this time, the torque generated on the surface of the inner cylinder 1 is measured. The viscosity change of the liquid sample can be continuously measured.

As described above, the maximum shear rate applied to the liquid sample at the narrow portion 13a having the smallest distance between the inner and outer cylinders 1 and 2 is the distance of the narrow portion 13a, the rotation speed of the inner and outer cylinders 1 and 2. It can be easily controlled by adjusting the speed difference.

Incidentally, when the shearing speed Dm in the narrow portion 13a rotates in the same direction, the distance between the outer surface of the inner cylinder 1 and the inner surface of the outer cylinder 2 (distance of the narrow portion 13a) is C (see FIG. 1), When the linear velocity of the inner surface of the inner cylinder 1 is Vi and the linear velocity of the outer surface of the outer cylinder 2 is Vo, it can be expressed by the following equation. Dm = (Vi-Vo) / C Therefore, if the distance of the narrow portion 13a and the speed difference between the inner and outer cylinders are determined in advance, the viscosity of the viscosity is determined when the maximum shear rate applied to the liquid sample is regulated. Measurement becomes possible.

[0017]

The present invention will be described in more detail with reference to the embodiments shown in the drawings.

FIG. 1 is an explanatory view showing the principle of the present invention in cross section, FIG. 2 is a front view of an example of an apparatus for carrying out the present invention, and FIG. 3 is a side view of the apparatus shown in FIG. Yes, Figure 4
FIG. 6 is an explanatory view showing a part of an apparatus according to another embodiment of the present invention, FIG. 5 is a graph showing a relation between torque acting on the inner cylinder and viscosity, and FIG. 6 is a relation between water content and torque. 7 is a graph showing the relationship between the stirring time and the torque, FIG. 8 is a graph showing the relationship between the water content and the torque ratio, and FIG. 9 is a graph showing the size (mm) of the narrowed portion. It is a graph which shows the shear rate (1 / sec) which is made.

First, in FIG. 2, the inner cylinder 1 is shown by a dotted line, and the inner cylinder 1 is connected to the drive motor 5 via the bearing 3 and the torque detecting portion 4. The driving motor 5 is preferably controllable so that the rotation speed of the inner cylinder 1 is within the range of 40 to 4000 rpm. The bearing 3, the torque detector 4 and the driving motor 5 are attached to a pedestal 6, the pedestal 6 is vertically movable, and the pedestal 6 is vertically moved by a motor 7.

The outer cylinder 2 is constructed so that it can be rotated at, for example, 0.1 to 120 rpm by the outer cylinder driving motor 9 around it. The inner cylinder 1 can be configured to rotate in only one direction, but the outer cylinder 2 can be configured to select either the same direction as the inner cylinder 1 or the opposite direction.

A constant temperature bath 8 in which a heat medium can be circulated is arranged around the outer cylinder 2 so that the temperature can be controlled. The outer cylinder 2, the constant temperature bath 8 and the outer cylinder driving motor 9 are installed on a pedestal 10 which can be moved horizontally, and the position can be adjusted by a feed screw 11.

With this structure, the pedestal 10 has the inner cylinder 1
The position can be adjusted in the range from the position where the rotation axes of the outer cylinder 2 are coincident and coaxial with each other to the position where the inner cylinder and the outer cylinder are in contact with each other, and thus the distance of the narrow portion 13a can be adjusted.

The torque received by the inner cylinder 1 due to the viscosity of the liquid sample to be measured is detected by the torque detection unit 4 connected to the inner cylinder 1. However, it is not always necessary to detect it by the torque detection unit 4. , A motor 5 for driving the inner cylinder 1
The torque can be detected by measuring the electric power of. The inner and outer cylinders 1 and 2 can be configured to have any size as desired, but normally, the diameter Do of the outer cylinder 2 is 30 mm, the diameter Di of the inner cylinder 1 is 20 mm, and the immersion length L of the inner cylinder is 60 mm.
It is preferable to adjust the degree.

Further, it is preferable that the narrow portion 13a formed between the inner and outer cylinders 1 and 2 has a thickness of about 0.1 to 2.0 mm. That is, the narrow portion 13a provides a predetermined stirring to the liquid sample to be measured as described above. Therefore, the narrow portion 13
If the size of a is too large, the stirring efficiency decreases,
For example, an emulsification close to the emulsified state of the printing ink in the printing unit cannot be obtained. On the other hand, if the size of the narrow portion 13a becomes too small, and is less than 0.1 mm, the working accuracy of the inner and outer cylinders 1 and 2 must be considerably increased, and the size of the narrow portion 13a will be affected by the fluctuation during rotation. Results in non-uniformity, resulting in errors.

Incidentally, the inner cylinder is 2000 rpm,
The outer cylinder was rotated at 60 rpm, and the relationship between the size of the narrowed portion and the shear rate of the liquid sample was determined.

Further, as shown in FIG. 4, a spiral groove 1a can be formed on the surface of the inner cylinder 1. This groove 1
a is formed so as to push the liquid sample downward during rotation, and the depth, width, pitch, etc. are determined according to the properties of the liquid sample to be measured. A size of 5 mm, a width of 3 mm, and a pitch of 5 mm are sufficient. Further, an inner cylinder having a smooth surface may be preferable depending on the liquid sample to be measured. Therefore, an inner cylinder 1 with a spiral groove 1a and an inner cylinder 1 having a smooth surface are prepared and used as a liquid sample. It is preferable to be able to replace it accordingly.

Further, in order to quantitatively supply the liquid to be measured, for example, a liquid supply device 12 (see FIG. 2) such as an electric buret or a metering pump is provided, and an annular recess 13 between the inner and outer cylinders 1 and 2 is provided. It is preferable to supply the liquid therein. With this configuration, the liquid sample can be supplied at a constant rate, and the change in viscosity can be measured while continuously changing the mixing ratio of the liquid sample.

Then, the manner of use of the above-mentioned measuring device will be described as follows.

First, a fixed amount of liquid sample (for example, 10c
(about c) is weighed in the outer cylinder 2. At this time, either one of the dispersion medium and the dispersoid in the liquid sample may be weighed in the outer cylinder 2 and the other may be supplied by the liquid supply device 12. If the dispersoid and the dispersoid are not separated but are separated and weighed in the outer cylinder 2 from the beginning, the measurement can be performed even when the dispersoid is solid.

Next, the outer cylinder 2 in which the liquid sample is weighed is set on the constant temperature bath 8. Therefore, the pedestal 6 is lowered, the upper and lower positions of the inner cylinder 1 are set, and then the pedestal 1 is fixed by the feed screw 11.
When 0 is moved in the horizontal direction, the relative position between the inner cylinder 1 and the outer cylinder 2 is determined, and the size of the narrow portion 13a is determined. In addition, a liquid supply device 12 such as an electric buret is set if necessary.

Then, the rotation of the inner and outer cylinders 1 and 2 is started, the torque at this time is observed while stirring the liquid sample in the narrow portion 13a, and the change in viscosity of the liquid sample is continuously measured.
At this time, when the liquid as the dispersoid, for example, water is supplied at a constant rate by the liquid supply device 12 such as an electric buret, for example, the mixing ratio of the liquid sample such as printing ink, that is, the water content is continuously changed. Meanwhile, the viscosity can be measured.

Further, the liquid sample has a viscoelastic property,
When there is a risk that the liquid sample winds around the outer surface of the inner cylinder 1 and rises up to the shaft portion of the inner cylinder 1 and scatters around, the inner cylinder 1 with a spiral groove 1a (see FIG. 4) is used. The sample is pushed down, allowing smooth measurement.

Further, in order to obtain the viscosity of the liquid sample in the agitated state from the torque detected by the torque detection unit 4, the viscosity as shown in FIG. -The torque relationship is measured and calculated from this result.

Next, an example of measuring the viscosity while emulsifying the planographic ink will be described.

Example 1 Two kinds of lithographic ink 10 cc were weighed in the outer cylinder 2, water was supplied at a constant speed by the liquid supply device 12, and emulsified to reproduce the same emulsified state as in actual printing. The "torque-time curve" of the planographic ink at this time was measured. In this case, when the water content at each time was calculated from the water supply rate, "torque-water content curves" (a) and (b) shown in FIG. 6 were obtained.

In general, the lithographic ink acts on the dampening water on the printing machine and has a high water content of 20 to 30%. When the water content of the planographic ink shown in FIG. 6 (a) exceeds 20% and the water content exceeds 20%, the torque is decreased and the density (ink film thickness) when printed is decreased. Recognize.

On the other hand, in the planographic ink shown by (B) in FIG. 6, even if the water supply amount is increased and the water content exceeds 20%, the torque does not decrease and the ink density does not decrease. I understand.

Example 2. A lithographic printing ink different from that of Example 1 was used as a liquid sample, and the viscosity was measured while emulsifying the viscosity in substantially the same manner as in Example 1 except for the following conditions. (1) The “torque-time curve” (c) shown in FIG. 7 was measured using only the printing ink as a liquid sample without supplying water. (2) The liquid sample was replaced, and the “torque-time curve” (d) shown in FIG. 7 was measured while supplying water. The ratio [(d) / (c)] of the torque of the curve (d) of (2) to the curve (c) of (3) and (1) was calculated. (4) Calculate the water content at each time from the water supply rate,
When a graph was created with the torque ratio calculated in (3), the "torque ratio-water content curve" (e) shown in FIG. 8 was obtained.

[0039]

As described in detail above, according to the present invention, a narrow portion is formed in a part of an annular space formed between inner and outer cylinders rotating with a speed difference, and a liquid sample to be measured in this annular space. The fluid is stirred while the fluid passes through the narrow portion, and the viscosity of the liquid sample at the time of stirring is measured by detecting the torque or the rotational driving force of either one of the inner and outer cylinders. Therefore, it is possible to continuously measure the change in viscosity with stirring of the liquid sample, and above all, it is possible to reliably obtain the change in viscosity while the printing ink such as offset passes through each printing unit.

In the above description, the printing ink was mainly described, but the present invention can be applied to a viscoelastic body or a liquid containing the viscoelastic body in addition to the printing ink.

Although the cylindrical inner and outer cylinders are mainly shown, any other shape such as a polygon having a shape of a triangle or more can be used as long as the narrow portion can be formed in a part of the annular space. Can also be configured.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the principle of the present invention in cross section.

FIG. 2 is a front view of an example of an apparatus for implementing the present invention.

3 is a side view of the device shown in FIG. 2. FIG.

FIG. 4 is an explanatory diagram showing a part of an apparatus according to another embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the torque acting on the inner cylinder and the viscosity.

FIG. 6 is a graph showing the relationship between water content and torque.

FIG. 7 is a graph showing the relationship between stirring time and torque.

FIG. 8 is a graph showing the relationship between water content and torque ratio.

FIG. 9 is a graph showing a size (mm) of a narrow portion and a given shear rate (1 / sec).

[Explanation of symbols]

 1 Inner Cylinder 1a Spiral Groove 2 Outer Cylinder 3 Bearing 4 Torque Detecting Part 5 Driving Motor 6 Pedestal 7 Motor 8 Constant Temperature Tank 9 Outer Cylinder Driving Motor 10 Pedestal 11 Feed Screw 12 Liquid Supply Device 13 annular recess 13a narrow portion

Claims (7)

[Claims] 1. A narrow portion is formed in a part of an annular space between rotating inner and outer cylinders, a liquid to be measured is put in the annular space, and then the inner and outer cylinders are rotated with a speed difference. While stirring the fluid in the narrow portion, the torque or the rotational driving force of either one of the inner and outer cylinders is detected,
A method for measuring the viscosity of a liquid while stirring the liquid, characterized in that the viscosity of the fluid is obtained from the detected value. 2. The method for measuring the viscosity of a liquid while stirring the liquid according to claim 1, wherein the width of the narrowed portion is adjusted according to the property of the liquid. 3. An inner cylinder that rotates with a speed difference compared to the rotation speed of the outer cylinder is arranged in the outer cylinder so as to be parallel to the rotation axis of the outer cylinder and spaced at a predetermined interval. Further, a device for measuring the viscosity of a liquid while stirring the liquid is provided with a detector for detecting the torque applied to the inner cylinder and / or the electric power of the motor for driving the inner cylinder. 4. The apparatus for measuring the viscosity of a liquid while stirring the liquid, according to claim 3, wherein the outer cylinder and the inner cylinder are formed in a cylindrical shape. 5. The viscosity of the liquid is measured while stirring the liquid according to claim 3 or 4, wherein the distance between the inner surface of the outer cylinder and the outer surface of the inner cylinder can be adjusted. Device to do. 6. An outer surface of the inner cylinder is provided with a spiral groove oriented in a direction in which a downward force acts on the liquid adhering to the inner cylinder during rotation. Or a device for measuring the viscosity of the liquid as described in 5, while stirring the liquid. 7. A liquid supply device for quantitatively supplying a liquid between the inner and outer cylinders is provided.
Or a device for measuring the viscosity of the liquid as described in 5, while stirring the liquid.