JPH11264789A - Rotary viscometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the viscosity of a fluid inspected of non-Newtonian fluid, in particular having a high viscosity, in the condition that it remains in a liquid chamber, etc., unchangedly. SOLUTION: A sensing spindle 10 is rotated at a very low speed in such a condition as set on a liquid chamber 25, and a fluid to be tested 26 is allowed to flow up in the gap relative to the inner wall surface of a bushing 17a of an outer cylinder 7 by a groove 24, and the gap between the outside circumferential surface of the spindle 10 and the inner wall surface of the bushing 17a is all wetted so that a uniform film thickness is obtained. In association with slide flow of the fluid 26 inside the gap, the reaction force due to the viscosity resistance acts on the spindle 10 in the reverse direction to its rotation. With this reaction force, the whole rotational drive part 1 and the base cylinder 8 rotate in the reverse direction to the rotational drive direction. Also an arm member 20 installed on the base cylinder 8 rotates, and an arm 21 abuts to a sensor arm 13a of a load cell 13. Because the abutting force at this time is proportioning to the reaction force due to the viscosity resistance of the fluid tested, the viscosity of the fluid 26 can be determined from the output value of the load cell 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotational viscometer capable of measuring the viscosity of a non-Newtonian fluid.

[0002]

BACKGROUND OF THE INVENTION Rotational viscometers have been widely known as devices for measuring the viscosity of non-Newtonian fluids. There are various types of rotational viscometers, but in general, a rotational drive unit,
It consists of a detection unit and a measurement unit.The detection unit is composed of a coaxial inner cylinder and an outer cylinder.The outer cylinder is fixed and the inner cylinder is driven to rotate by the rotation drive unit. There is an inner cylinder rotation type that measures by the measuring unit, and conversely, an outer cylinder rotation type that fixes the inner cylinder and rotates the outer cylinder. In any case, this type of rotational viscometer generally includes a cylindrical cup (outer cylinder) into which a test fluid is charged, and a cup around the center axis of the cup while being in contact with the test fluid charged inside the cup. A rotor (inner cylinder) which is rotatably supported independently of the rotor and a rotation driving means for rotating the rotor or the cup around the central axis thereof. On the other hand, the viscosity of the test fluid is measured by measuring the rotational torque transmitted via the test fluid. The cup or the rotor is not always cylindrical, and conical or other shapes are widely used. Since such a viscometer and its measuring principle are well known, the details are omitted.

[0003] All of the known rotary viscometers of this type are of the batch type as described above. For example, the viscosity of a test fluid in a liquid tank or piping is measured as it is in the liquid tank inner cylinder. Rather than measuring, the test fluid is once taken out of the liquid tank etc. as a sample and measured.Therefore, whether the measured value actually indicates the viscosity of the test fluid when it is in the liquid tank etc. There was no guarantee, and a solution was desired.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a rotary viscometer capable of measuring viscosity in a state where a test fluid is actually in a liquid tank or piping, in other words, inline. Aim.

[0005]

According to the present invention, there is provided a rotational viscometer according to claim 1 for achieving the above object.
A rotation viscometer for measuring the viscosity of a test fluid that is a non-Newtonian fluid, comprising a rotation drive unit, a detection unit, and a measurement unit, wherein the detection unit includes a coaxial inner cylinder and an outer cylinder, The inner cylinder rotating type viscometer, wherein the outer cylinder is fixed and the inner cylinder is rotatable by the rotation drive unit, and the viscous torque received by the inner cylinder during rotation is measured by the measurement unit. A base cylinder mounted with the rotation drive unit and rotatably supported in the outer cylinder, and a base end connected to the rotation drive unit to penetrate through the base cylinder and pass through the base cylinder. A rotating shaft freely rotatably supported, and a detection cylinder having a portion formed with a spiral groove on the outer peripheral surface and connected and fixed to the tip of the rotation shaft, and forming a groove between the outer cylinder and the detection cylinder. When the gap of the fitting part with the part is allowed to rotate the detection cylinder, In addition, the test fluid that has entered the gap has a shear flow speed given by the rotation of the detection cylinder, and has a dimension that allows the test fluid to flow, and the measurement unit controls the rotation cylinder to rotate the detection cylinder through the rotation shaft. When driven to rotate, the base cylinder rotates in the direction opposite to the rotational drive direction of the detection cylinder, by the reaction force of viscous torque that is caused by the shear stress due to the shear flow of the test fluid into which the detection cylinder has entered the gap. The rotation torque of the rotation drive unit is detected.

According to a second aspect of the present invention, the rotation drive section rotates the rotation shaft and the detection cylinder at a very low speed.

According to a third aspect of the present invention, the tip of the detection tube is projected from the fitting portion with the outer tube so that a part of the groove is exposed.

According to a fourth aspect of the present invention, an opening for overflowing and discharging the test fluid which has risen in the gap is provided above a fitting portion of the outer cylinder with the groove forming portion of the detection cylinder. Is provided.

According to a fifth aspect of the present invention, a magnetic body is made to face each of the inner peripheral surface of the outer cylinder and the outer peripheral surface of the base cylinder. Are arranged so as to push up.

According to a sixth aspect of the present invention, the magnetic body provided on the outer peripheral surface of the base cylinder is arranged so as to be shifted upward from the magnetic body provided on the inner peripheral surface of the outer cylinder. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the following, only the viscosity measurement example for the test fluid flowing in the pipe will be described,
The present invention is not limited to this, and it is not an essential condition that the test fluid is flowing.Referring to the description below, the test fluid that has been stored and is not flowing may have a certain condition. It is apparent that the measurement can be performed similarly.

FIG. 1 is a sectional view showing an embodiment of a rotational viscometer according to the present invention, and FIG. 2 is a plan view thereof. The rotational viscometer according to the present embodiment mainly includes a rotation drive unit 1, a detection unit 2, and a measurement unit 3. The rotation drive unit 1 includes a DC servo motor 4,
It comprises a speed reducer 5 and a coupling 6. Detector 2
Is composed of an outer cylinder 7, a base cylinder 8, which forms an inner cylinder coaxial with the outer cylinder 7, a rotating shaft 9, and a detection spindle 10. The measuring unit 3 further includes a gear 11 mounted on the rotating shaft 9 and the proximity sensor 1.
2 and a load cell 13. In the figure, reference numeral 14 denotes a base plate, on which the proximity sensor 12, the load cell 13, and the outer cylinder 7 are fixed.

The outer cylinder 7 is a hollow cylinder having a distal end projecting downward through a hole formed in the base plate 14 and an upper end fixed to the base plate 14. Also, on the upper side of the hollow interior,
The base cylinder 8 constituting the inner cylinder is supported via a pair of bearings 15 and 15 so as to be freely rotatable. A pair of openings 16, 16 is provided below the portion supporting the base cylinder 8, and the lower side is a fitting portion 17 for fitting to the detection spindle 10. The bush 1 is located inside the fitting portion 17.
7a is attached.

The base cylinder 8 constituting the inner cylinder is also a hollow cylinder, which is supported in the outer cylinder 7 so as to be freely rotatable as described above, and provided with a pair of bearings 18 and 18 in the hollow interior. 9
Is supported so that it can rotate freely. The rotating shaft 9 penetrates through the hollow inside of the base cylinder 8, has an upper end connected to an output shaft of the speed reducer 5 of the rotary drive unit 1 via a coupling 6, and has a lower end connected and fixed to a detection spindle 10. The gear 11 is attached to the rotary shaft 9 immediately below the coupling portion of the coupling 6 as described above, and the gear 11 rotates with the rotary shaft 9.

An arm member 20 for detecting a rotational torque is mounted on the upper end of the base cylinder 8 so as to rotate together with the base cylinder 8 around a coaxial axis. The illustrated arm member 20
Has a pair of arms 21 for the purpose of balance, so that only one arm 21 comes into contact with the sensor arm 13a of the load cell 13 during rotation. A bracket 23 is mounted on the upper surface of the arm member 20 via four columns 22..., And the DC servo motor 4 and the speed reducer 5 are provided on the bracket 23. Is connected to the rotating shaft 9 below the hole provided in the shaft. In the illustrated example, since the central portion of the arm member 20 and the bracket 23 have the same shape, they overlap in FIG. 2 which is a plan view.

The detection spindle 10 is connected to the fitting portion 1 of the outer cylinder 7.
A spiral groove 24 is formed on the outer peripheral surface of the distal end located inside 7. The groove 24 is cut with a right-hand thread, and as shown in an enlarged view in FIGS. 3 and 4, has a slope-shaped cross-section that is inclined downward outward to lower the groove bottom in order to raise the test fluid during rotation. The upper surface of the groove has a cross-sectional shape extending horizontally outward. However, the cross-sectional shape of the groove 24 is merely an example, and the present invention is not limited to this groove shape. Further, the tip of the detection spindle 10 has a length protruding, for example, several mm from the fitting portion 17 when attached to the outer cylinder 7, and detects a gap formed between the tip portion and the inner wall surface of the fitting portion 17. The spindle 10 is designed to be rotatable, and the test fluid that has entered the gap is given a shearing speed by the rotation so as to be sheared. This size may be determined based on conventionally known research results, experimental results, and the like.

That is, in the above configuration, not only the base cylinder 8, the rotating shaft 9, the detection spindle 10, and the arm member 20 but also the
The entire rotation drive unit 1 including the DC servo motor 4, the speed reducer 5, the support 22, the bracket 23, and the like can be freely rotated by external force, for example, by turning by hand. If the detection spindle 10 is rotated by an external force, for example, by hand in a state where the DC servo motor 4 and the speed reducer 5 are not driven to rotate, the rotating body in the DC servo motor 4 and the speed reducer 5 is connected to the rotating shaft 9. The DC servomotor 4, the entire reduction gear 5, and the base cylinder 8 are eventually rotated by the external force of the detection spindle 10 due to the rotational resistance of the members and elements that support the rotating body.

Next, the use of the rotational viscometer according to the present embodiment will be described with reference to the above-mentioned drawings and FIG. For example, the base plate 14 of the rotational viscometer having the above-described configuration is fixed and set by a suitable holding means on a liquid tank 25 containing a test fluid,
The fitting part 17 of the outer cylinder 7 is immersed in the test fluid 26 in the liquid tank 25 to the middle, and even if the liquid level of the test fluid 26 changes due to flow, inclination, etc. in the liquid tank 25, the detection spindle 10 Groove 2
The tip provided with 4 does not come out of the liquid surface. That is, in the rotational viscometer of the present embodiment, as described later, it is important to keep the state of the test fluid 26 constant in the gap between the outer peripheral surface of the detection spindle 10 and the inner wall surface of the bush 17a. This is because if the tip side of the spindle 10 comes out above the liquid level, a certain state cannot be maintained.

Then, by driving the DC servo motor 4 and decelerating by the speed reducer 5, the rotating shaft 9 is driven to rotate at the lowest possible speed, and the detection spindle 10 is rotated while preventing the test fluid 26 from causing structural destruction as much as possible. Let it. Then, the test fluid 26 flowing near the distal end of the detection spindle 10 has a gap with the inner wall surface of the bush 17 a attached to the fitting portion 17 of the outer cylinder 7 by the groove 24 of the detection spindle 10 even if it has a high viscosity. Entry, test fluid 2
6 rises spirally along the groove 24 due to its own viscosity and the cross-sectional shape of the groove 24. That is, the upward movement is a shear flow of the test fluid 26 in a gap between the outer peripheral surface of the detection spindle 10 and the inner wall surface of the bush 17a, and the rotational driving force received by the detection spindle 10 is generated as shear stress. When shear stress occurs, shear deformation occurs in the test fluid 26 as is well known, and the outer peripheral surface of the detection spindle 10 and the bush 17
This causes shear deformation of the test fluid 26 in the gap between the inner surface of the test fluid 26a. As is well known, the velocity gradient caused by this shear deformation is the shear velocity. By causing the above-mentioned shear flow over the entire gap between the outer peripheral surface of the detection spindle 10 and the inner wall surface of the bush 17a, the test fluid 26
Is given, and the viscosity of the test fluid 26 is measured by observing the change in the shear stress caused by the shear speed.

When the detection spindle 10 is continuously rotated for a certain period of time, the test fluid 26 which has risen in the gap between the outer peripheral surface of the detector spindle 10 and the inner wall surface of the bush 17a is raised.
Overflows from the opening 16 at the bottom of the base cylinder 8. As long as this state is maintained, the outer peripheral surface of the detection spindle 10 and the inner wall surface of the bush 17a are all wet with the test fluid 26, and the test fluid 26 in the gap has a uniform film thickness, a moving speed,
The moving state and the like are kept constant.

Of course, the test fluid 26 begins to enter the gap between the outer peripheral surface of the detection spindle 10 and the inner wall surface of the bushing 17a, but the reaction force due to the viscous torque accompanying the shear flow of the test fluid 26 in the gap. Is applied to the detection spindle 10 as an external force in a direction opposite to the rotation direction. Then, as described above, the external force applied to the detection spindle 10 also causes the DC servo motor 4, the entire reduction gear 5, and the base cylinder 8 to rotate.
2 rotates very slowly in the opposite direction (the direction of the arrow B in FIG. 2) to the rotational drive direction (the direction of the arrow A in FIG. 2). Then, the arm member 20 attached to the base cylinder 8 also rotates, and the arm 21 on the load cell 13 side contacts the sensor arm 13a of the load cell 13.

The contact force of this arm 21 is
Is proportional to the rotational torque of the reaction force due to the viscous torque of
If the output value of a fluid having a known viscosity is known in advance, the viscosity of the test fluid 26 can be measured by detecting the output value of the load cell 13 when the test fluid 26 is in the above-described constant state. By changing the rotation speed of the detection spindle 10 according to the test fluid 26, it is possible to measure the viscosity at various shear speeds as in the case of a conventional general rotation viscometer. In the present embodiment, the output signal of the load cell 13 indicates the peak of the gear 11 by the proximity sensor 1.
Sampling is performed at the timing detected in step 2. Needless to say, appropriate timing detecting means such as a rotary encoder and an optical sensor may be used instead of the gear and the proximity sensor. Further, conversion and processing of the output signal of the load cell 13 are very well-known items, and thus description thereof is omitted. Of course, it is also possible to use a load sensor other than the load cell.
That is, various known means may be adopted as the measuring means.

FIG. 6 is a sectional view showing a second embodiment of the rotational viscometer according to the present invention. The rotational viscometer of the present embodiment includes:
Instead of supporting the base cylinder 8 with the bearings 15, the outer cylinder 7
In addition, a strong magnet is attached to each of the base cylinder 8 and the base cylinder 8 is self-centeringly supported.

The holding member 2 is provided at the upper and lower ends of the hollow inside of the outer cylinder 7.
7 and 28 are provided, and a pair of annular magnets 29 and 30 are provided. Also, at the upper and lower ends of the outer periphery of the base cylinder 8, annular magnets 31, 3 slightly smaller in diameter than the inner diameters of the annular magnets 29, 30 of the outer cylinder 7.
2 are provided. These magnets 31 and 32 have opposite polarities to the magnets 29 and 30 of the outer cylinder 7 which are located at substantially the same height in the vertical direction. In the drawing, a spacer 33 is provided for forcibly maintaining a gap between the magnet 29 on the upper side of the outer cylinder 7 and the magnet 31 on the upper side of the base cylinder 8.

The magnets 31 and 32 on the side of the base cylinder 8 are
The magnets 29 and 30 are slightly shifted upward. Therefore, between the outer cylinder 7 and the base cylinder 8, the magnets 29, 3
1. The biasing force that acts upon the repulsion of the magnetic field between the magnets 30 and 32 acts to push the base cylinder 8 upward. Further, the urging force is uniformly applied to the base cylinder 8 from the outer periphery. For this reason, when the base cylinder 8 tries to fall into the outer cylinder 7 by its own weight and the above-described pushing force are balanced, the base cylinder 8 is supported in a self-centering manner. That is, in the previous embodiment, when the base cylinder 8 rotates, the sliding contact with the bearing 15 may cause a frictional force in a half-rotational direction, which may hinder the detection of the delicate viscosity. Because there is no sliding contact, the rotational torque of the reaction force due to the viscous torque of the test fluid 26 can be detected without any obstacle. Other configurations and operations are the same as those of the previous embodiment, and a description thereof will be omitted.

FIG. 7 is a sectional view showing a third embodiment of the rotational viscometer according to the present invention. The rotational viscometer of the present embodiment includes:
The outer cylinder 7 has only a trumpet-shaped magnet 34 provided at the upper end and having a wide opening at the upper side, and a portion having a wide opening at the lower side at the lower end side, and the magnets 35 and 36 of the base cylinder 8 are formed as truncated cones. Things. The magnet 35 of the base cylinder 8 is provided so as to enter the trumpet-shaped magnet 34 of the outer cylinder 7.
6 is provided at an opening on the lower end side of the outer cylinder 7. In addition, base cylinder 8
The polarity of the magnet 35 is set so as to repel the trumpet-shaped magnet 34 of the outer cylinder 7, and the polarity of the magnet 36 is set so as to attract the magnet 34. And like the previous embodiment,
The upper magnets 34 and 35 are provided such that the magnet 35 of the base cylinder 8 is located slightly above the magnet 34 of the outer cylinder 7. With this configuration, the magnets 34 and 35 repel each other, and the magnets 34 and 36 attract each other.
As in the case of the embodiment, the base cylinder 8 tends to fall into the outer cylinder 7 by its own weight, and the repulsion and the attraction between the magnets balance the forces, and the base cylinder 8 is supported in a self-centering manner. Other configurations and operations are the same as those of the previous embodiment, and a description thereof will be omitted.

[0027]

As described above, according to the present invention, the test fluid is not taken out to another place or the like in a state where the test fluid is actually in the liquid tank or the pipe, so to say, in-line. Viscosity can be measured, and there is an effect that accurate viscosity can be measured in a constant state even for a fluid that causes structural destruction at the time of removal.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a rotational viscometer according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is an enlarged partial cross-sectional view of a detection spindle constituting the inner cylinder.

FIG. 4 is an enlarged sectional view of a groove provided in a detection spindle.

FIG. 5 is a sectional view showing a use state of an embodiment of the rotational viscometer according to the present invention.

FIG. 6 is a sectional view showing a second embodiment of the rotational viscometer according to the present invention.

FIG. 7 is a sectional view showing a third embodiment of the rotational viscometer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotation drive part 2 Detecting part 3 Measurement part 4 DC servomotor 5 Reduction gear 6 Coupling 7 Outer cylinder 8 Base cylinder 9 Rotating shaft 10 Detection spindle 11 Gear 12 Proximity sensor 13 Load cell 14 Base plate 15 Bearing 16 Opening 17 Fitting part 17a bush 18 bearing 20 arm member 21 arm 13a load cell sensor arm 22 support 23 bracket 24 detection spindle groove 25 piping 26 test fluid 27, 28 holding member 29, 30, 31, 32, 34, 35, 36 magnet 33 spacer

Claims (6)

[Claims] 1. A rotational viscometer for measuring the viscosity of a test fluid that is a non-Newtonian fluid, comprising: a rotation drive unit, a detection unit, and a measurement unit, wherein the detection unit includes: a coaxial inner cylinder; An inner cylinder rotating type viscometer, comprising an outer cylinder, fixing the outer cylinder, enabling the inner cylinder to be rotationally driven by the rotation drive unit, and measuring the viscous torque received by the inner cylinder during rotation by the measuring unit. In the above, the inner cylinder is mounted with the rotation drive unit and supported freely rotatably in the outer cylinder, and a base end is connected to the rotation drive unit and penetrates through the base cylinder. A rotating shaft freely rotatably supported in the base cylinder, and a detection tube having a portion formed with a spiral groove on the outer peripheral surface and being connected and fixed to the tip of the rotating shaft; The gap between the fitting part and the groove forming part of the detection cylinder is While allowing rotation, the test fluid having entered the gap has a shear flow rate given by the rotation of the detection tube and has a dimension such that the test fluid flows, and the measuring unit detects the fluid by the rotation drive unit via the rotation shaft. When the cylinder is rotationally driven, the detection cylinder is rotated in a direction opposite to the rotational driving direction of the detection cylinder by a reaction force of viscous torque received by the shear stress due to the shear flow of the test fluid having entered the gap. A rotational viscometer for detecting rotational torque of a cylinder and the rotational drive unit. 2. The rotational viscometer according to claim 1, wherein the rotation drive section rotates the rotation shaft and the detection cylinder at a very low speed. 3. The rotational viscometer according to claim 1, wherein a tip of the detection cylinder is projected from the fitting portion with the outer cylinder so that a part of the groove is exposed. 4. An opening for overflowing and discharging the test fluid that has risen in the gap is provided above a fitting portion of the outer cylinder with a groove forming portion of the detection cylinder. The rotational viscometer according to any one of claims 1 to 3, wherein 5. A magnetic body is made to face each of an inner peripheral surface of the outer cylinder and an outer peripheral surface of the base cylinder, and both magnetic bodies are arranged so that their magnetic fields repel each other and push up the base cylinder. The rotational viscometer according to any one of claims 1 to 4, wherein: 6. The rotational viscometer according to claim 5, wherein the magnetic material provided on the outer peripheral surface of the base cylinder is arranged to be shifted upward from the magnetic material provided on the inner peripheral surface of the outer cylinder. .