JP2018146312A - Apparatus and method for measuring viscosity and elasticity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for measuring viscosity and elasticity, capable of simply measuring the viscosity of a sample material in a wide range from low viscosity to high viscosity with high accuracy as compared with conventional one.SOLUTION: An apparatus for measuring viscosity and elasticity comprises: a rotor a part or the entire body of which is constituted by a material having conductivity and which has a projection at the center of rotation in the lower part; a sample vessel into which a substance to be detected whose viscosity is detected is injected and in which the rotor contacting the substance to be detected and its projection contacting its inner bottom arranged; a rotation control part for applying a magnetic field to the rotor to induce an induction current and to rotate the rotor by running torque caused by Lorentz interaction between the induced current and the magnetic field applied to the rotor; a rotation detection part for detecting the rotational speed of the rotor; and a viscosity elasticity detection part for detecting the viscosity and elasticity of the substance to be detected contacting the rotor by the rotational speed. The centroid position of the rotor is closer to the projection than a buoyancy position due to buoyancy generated corresponding to a portion of the rotor sunk in the substance to be detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a viscosity / elasticity measuring apparatus and a viscosity / elasticity measuring method for measuring viscosity / elasticity which are mechanical properties of a substance.

Conventionally, in order to detect the mechanical properties of a target substance, viscosity (sometimes referred to as viscosity in the following description) and elasticity are measured (for example, see Patent Document 1).
Viscosity / elasticity measurement includes quality control, performance evaluation, raw materials in the manufacturing process of pharmaceuticals, foods, paints, inks, cosmetics, chemical products, paper, adhesives, fibers, plastics, beer, detergents, concrete admixtures, silicon, etc. It is an indispensable measurement technology for management and research and development.
In a conventionally known viscosity measurement method, a driving torque is applied to a rotating probe (rotor) in contact with a sample to be measured in a non-contact manner, and the viscosity of the target sample is determined from the rotation speed of the rotating probe. There is a device that measures non-contact (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

In Patent Document 1, as a rotor, a conductive small sphere is submerged in a sample, a predetermined torque is applied in a non-contact manner, and the viscosity of the sample is measured in a non-contact manner from the rotation speed of the small sphere.
Patent Document 2 uses either or both of buoyancy and surface tension to float a disk-shaped rotor on the surface of a sample, applies a predetermined torque in a non-contact manner, and from the rotational speed of the rotor, Viscosity is measured without contact.
In Patent Document 3, the tip of the rotation center at the bottom of the rotor is formed in a convex shape, the tip contacts the inner bottom of the container for storing the sample, and the rotation shaft is provided at the top of the rotor. The rotating shaft is held by a rotatable mechanism, and the direction of the rotating shaft is fixed. A predetermined torque is applied to the rotor in a non-contact manner, and the viscosity of the sample is measured in a non-contact manner from the rotational speed of the rotor.

JP 2009-264982 A JP 2012-242137 A JP 2006-031352 A

However, in the above-mentioned Patent Document 1, the flow rate of the sample around the small sphere is not known for a non-Newtonian liquid, and the shear rate that gives viscosity cannot be uniquely determined, and measurement of low viscosity such as pure water is not possible. Accuracy cannot be obtained.
In Patent Document 2, when measuring the viscosity, it is necessary to accurately measure the distance (flying height) between the rotor and the bottom of the container. However, the measurement varies depending on the amount of the sample accommodated in the container. In order to measure the distance every time, a highly accurate measuring instrument is required. The flying height fluctuates due to the evaporation of the sample, the change in the specific gravity of the sample accompanying a change in temperature, or the change in wettability between the rotor and the sample. For this reason, the measurement accuracy of the viscosity of the sample may change depending on the surrounding environment.

  In Patent Document 3, the measurement accuracy for a sample having a low viscosity such as pure is lowered due to friction between a rotating shaft provided on the upper portion of the rotor and a mechanism for holding the rotating shaft. When increasing the accuracy, it is necessary to give a high-speed rotation of one rotation or more per second, and the accuracy of viscosity measurement in the low shear rate region cannot be improved. In addition, if the sample evaporated in the container is condensed between the rotating shaft and the mechanism that holds this rotating shaft, the rotational speed of the rotor is affected by the surface tension of the condensed sample, and the measurement accuracy decreases. There is a case.

  The present invention has been made in view of such circumstances. The sample container into which the substance to be detected is placed can be made inexpensive and disposable, and the viscosity of the sample substance over a wide range from low viscosity to high viscosity can be reduced. An object of the present invention is to provide a viscosity / elasticity measuring apparatus and a viscosity / elasticity measuring method which can be measured more easily and with higher accuracy than in the past.

  In order to solve the above-described problems, the viscosity / elasticity measuring apparatus according to the present invention includes a rotor having a protruding protrusion at the center of rotation, partially or entirely made of a conductive material, and a viscosity. A sample container in which the rotor is arranged in a state in which a detection target substance to be detected is placed, and the protrusion is in contact with the detection target substance and in contact with the bottom of the inner surface of the target, and the rotor varies with time A rotation control unit that applies a magnetic field, induces an induced current in the rotor, and rotates the rotor by applying a rotational torque by Lorentz interaction between the induced current and the magnetic field applied to the rotor; A rotation detection unit that detects a rotation speed of the rotor, and a viscoelasticity detection unit that detects the viscosity and elasticity of the detection target substance in contact with the rotor based on the rotation speed number of the rotor, Detecting the rotor From the center of buoyancy position by the buoyancy occurring in response to the portion submerged elephant substance, the center of gravity of the rotor is equal to or close to the projection.

  The viscosity / elasticity measuring apparatus of the present invention is characterized in that the radius of the rotor of the rotor is determined by the following equation (14).

  In the viscosity / elasticity measuring apparatus of the present invention, the distance between the center of gravity position and the buoyancy position is set to be equal to or greater than a distance having a restoring force that holds the rotation axis in the vertical direction in the rotation of the rotor. And

  The viscosity / elasticity measuring apparatus according to the present invention includes a storage unit for storing standard data in which a relationship between a rotational torque applied to the rotor in a plurality of substances whose viscosity is known and a rotational speed of the rotor is measured in advance. Further, the viscosity / elasticity of the detection target substance is obtained by comparing the standard data with the relationship between the rotational torque and the rotation speed of the detection target substance detected by the viscosity detection unit.

  In the viscosity / elasticity measuring apparatus of the present invention, a mark is attached to the surface of the rotor, and the rotation detector detects the rotation of the mark by detecting the rotation of the mark. And

  The viscosity / elasticity measuring apparatus of the present invention detects the rotational speed of the rotor by irradiating the rotor of the rotor with a laser and optically measuring a change in reflected light or interference pattern. It is characterized by doing.

  The viscosity / elasticity measuring apparatus according to the present invention is characterized in that the rotor is formed so as to be thinner in proportion to the distance from the rotation shaft with respect to the diameter direction of the rotor.

  The viscosity / elasticity measuring apparatus according to the present invention is characterized in that the rotor bottom plate is formed so as to become thinner in proportion to the distance from the rotation shaft with respect to the diameter direction of the rotor bottom plate.

  In the viscosity / elasticity measuring method of the present invention, a detection target substance whose viscosity and elasticity are to be detected is accommodated in a sample container, and a part or the whole is made of a conductive material, and protrudes at the center of rotation at the lower part thereof. A process in which a rotor having a protrusion is placed in contact with the substance to be detected and the protrusion is in contact with the bottom of the inner surface of the rotor, and a time-varying magnetic field is applied to the rotor. A process of inducing an induced current in the rotor and applying a rotational torque to the rotor by Lorentz interaction between the induced current and a magnetic field applied to the rotor, and a rotation speed of the rotor. A buoyancy generated in correspondence with a portion of the rotor submerged in the detection target material, including a detection process and a viscosity detection step of detecting the viscosity / elasticity of the detection target material in contact with the rotor according to the rotation speed Buoyant position More, the center of gravity of the rotor is equal to or close to the projection.

  As described above, according to the present invention, the sample container into which the substance to be detected is placed can be made inexpensive and disposable, and the viscosity of the sample substance over a wide range from low viscosity to high viscosity is compared with the conventional one. Thus, it is possible to provide a viscosity / elasticity measuring apparatus and a viscosity / elasticity measuring method which can be measured easily and with high accuracy.

It is a schematic block diagram which shows the structural example of the viscosity and elasticity measuring apparatus by one Embodiment of this invention. It is a figure which shows the structural example of the sample container and rotor in the viscosity / elasticity measuring apparatus shown in FIG. FIG. 4 is a conceptual view of the sample container 2 as viewed from the side in order to explain the arrangement of the rotor 1 in the sample 100 accommodated in the sample container 2. It is the conceptual diagram which looked at the sample container 2 from the side surface in order to demonstrate other arrangement | positioning of the rotor 1 in the sample 100 accommodated in the sample container 2. FIG. It is a top view which shows the fixed state of the magnet provided in order to generate | occur | produce the rotating magnetic field in the magnet fixing stand. It is a figure which shows the relationship between rotation speed (ohm) M of the motor 4, and each rotation speed (omega | ohm) D of the rotor 1 in a corresponding standard sample in the standard sample which has several different viscosity (eta). It is a figure which shows the shear rate dependence of each sample (sample A and sample B) calculated | required from the relationship diagram shown in FIG. It is a figure which shows the electromagnet by which the yoke 10 and the teeth 10a, 10b, 10c, and 10d which protruded from this yoke 10 are arrange | positioned on the reference | standard two-dimensional plane. FIG. 6 is a schematic diagram illustrating another configuration example of the shape of the rotor bottom plate in the rotor 1. It is a figure which shows the relationship between rotational speed (omega) M (namely, rotational torque) of the motor 4, and rotation angle (theta) which the rotor 1 stops. It is a figure which shows the relationship between elasticity and the ratio of a rotational speed and a rotation angle.

Hereinafter, a viscosity / elasticity measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG.1 and FIG.2 is a schematic block diagram which shows the structural example of the viscosity and elasticity measuring apparatus by one Embodiment of this invention. FIG. 1 shows the overall configuration of the viscosity / elasticity measuring apparatus. FIG. 2 is a diagram showing a configuration example of a sample container and a rotor in the viscosity / elasticity measuring apparatus shown in FIG.
In FIG. 1, the viscosity / elasticity measuring apparatus according to the present embodiment includes a rotor 1, a sample container 2, a first magnet 3_1, a second magnet 3_2, a third magnet 3_3, a fourth magnet 3_4, a motor 4, and a rotation detection sensor. 5, a sample table 6, a magnet fixing table 7, and a viscosity measuring unit 8.

  As shown in FIG. 2, the rotor 1 is formed of a rotor bottom plate 1A and a floating portion 1B. The rotor bottom plate 1A is formed of a disk-shaped member, for example, a metal material, and a part or all (the whole) of the rotor bottom plate is composed of a conductor (for example, a metal material). For example, only a part of the rotor bottom plate 1A uses a conductor such as aluminum, and the other part can be made of a material such as plastic or vinyl. That is, the rotor bottom plate 1A may be formed by attaching a commercially available aluminum foil or the like to the upper surface of a plastic disc. Thus, an inexpensive rotor bottom plate 1A can be easily formed from a commercially available plastic disc and a commercially available alum foil.

The floating portion 1B is a cylindrical (right column) floating body that is coaxial with the rotor bottom plate 1A, and has an outer periphery that overlaps with the outer periphery of the rotor bottom plate 1A in plan view from the top. That is, the section perpendicular to the central axis of the floating portion 1B overlaps the rotor bottom plate 1A in plan view. Further, the floating portion 1B is formed as a configuration having a greater buoyancy than the rotor bottom plate 1A. Thereby, the rotor 1 has a rotationally symmetric shape with respect to the central axis of the rotor bottom plate 1A (the central axis of the floating portion 1B), and rotates about the central axis. It faces the vertical (vertical) direction with respect to the surface of the bottom plate 1A.
In addition, since rotation detection is performed on either one of the rotor bottom plate 1A and the floating portion 1B (described later), any one of the surfaces (the rotor bottom plate 1A in the present embodiment) can be detected by an imaging device or the like. A size mark is provided.

  The sample container 2 includes a sample container main body 21 and a sample container lid 22. Further, the sample container 2 accommodates a detection target object (hereinafter referred to as a sample) for measuring a viscosity (that is, a viscosity coefficient) η as a mechanical physical property. Each of the sample container main body 21 and the sample container lid 22 is made of a material such as glass or plastic. The sample container main body 21 is a cylindrical sample container such as a small petri dish. The inner diameter of the sample container main body 21 only needs to be slightly larger than the diameter of the rotor bottom plate 1A (and the floating portion 1B) in the rotor 1.

  The sample container lid 22 is used to completely block the sample 100 from the external environment (outside air, etc.) in order to prevent evaporation of the sample 100 accommodated in the sample container main body 21 and mixing of foreign substances. If not, you do not need to prepare. In this sample container 2, the rotor 1 is disposed so that the rotor bottom plate 1A and the floating portion 1B are in contact with the sample 100 that is the detection target, that is, a part or all of the rotor 1 is immersed in the detection target. ing. As the sample container 2, a commercially available petri dish or the like made of glass or plastic can be used for both the sample container main body 21 and the sample container lid 22. For this reason, the sample container 2 can be a disposable commercially available sample container and can be prepared at low cost.

As described above, in this embodiment, the rotor 1 and the sample container 2 can be made inexpensive. For this reason, when the biomaterial or the like becomes the sample 100, the rotor 1 and the sample container 2 can be easily discarded even if a substance requiring special attention is discarded.
As a result, as with post-treatment problems such as incineration and sterilization, it can be easily performed as with the disposal of other medical instruments.

  FIG. 3 is a conceptual view of the sample container 2 viewed from the side in order to explain the arrangement of the rotor 1 in the sample 100 accommodated in the sample container 2. In FIG. 3, the floating portion 1 </ b> B is disposed on the upper surface of the rotor bottom plate 1 </ b> A, has a cylindrical shape with only an outer peripheral surface with an open top, and the interior 200 is a space. Due to the space of the interior 200, buoyancy corresponding to the specific gravity of the sample 100 is generated on the rotor 1. As the outer peripheral surface of the floating portion 1B, a cylindrical plate made of a resin plate or the like, or a cylinder formed by cutting a resin pipe perpendicular to the central axis and using the outer peripheral wall of the cut pipe is used. be able to. Further, the floating portion 1B may be a cylinder in which the internal space is sealed, a cylinder in which the interior 200 is filled with other members, or a column having no internal space. When a cylinder having no internal space is used as the floating portion 1B, a part or all of the bottom surface of the floating portion 1B may be formed of metal or the like, and the floating portion 1B itself may be used as the rotor 1. Even in this case, it is necessary to satisfy the relationship between the buoyancy and the center of gravity described below.

A mark 30 is arranged on the upper surface of the side wall of the floating portion 1B. The mark 30 may be arranged at a position readable by the imaging device on the upper surface of the rotor bottom plate 1A. The change in the position of the mark 30 is optically read by a sensor or an imaging device, and the rotational speed of the rotor 1 is obtained to calculate the rotational speed of the rotor 1. In the present embodiment, the rotor bottom plate 1A is formed of a metal disk.
Further, on the lower surface of the rotor bottom plate 1 </ b> A, a metal protruding protrusion 1 </ b> C that is brought into contact with the inner surface bottom of the sample container main body 21 is provided. The protrusion 1C is in contact with the bottom of the groove 21C provided on the inner bottom of the sample container main body 21. The rotor 1 rotates in a state where the protrusion 1C is inserted into the groove 21C. For this reason, the distance between the lower surface of the rotor bottom plate 1A and the bottom surface inside the sample container main body 21 can be kept constant with high accuracy, and the shear rate of the rotor bottom plate 1A in the sample 100 can be stably maintained. The accuracy of the viscosity measurement of the sample 100 is improved.

In this embodiment, about 60% of the weight of the rotor 1 is the mass of the member constituting the rotor bottom plate 1A, and the remaining about 40% of the weight of the rotor 1 is the mass of the member constituting the floating portion 1B. is there. When the weight of the rotor 1 is about 1.3 g (grams), the magnitude of gravity applied to the rotor 1 is 1.3 gram weight. Here, when the volume of the hollow portion inside the rotor 1 is about 0.8 cm ³ and the specific gravity of the sample is 1.0 g / cm ³ , the maximum buoyancy applied to the rotor 1 is 0.8 gram weight. is there. For this reason, the rotor 1 does not completely float in the sample 100 accommodated in the sample container 2, and a portion corresponding to a predetermined volume is shown in each of FIGS. 3 (a) and 3 (b). It will be in a sunk state.

  FIG. 3A shows a state where the rotor 1 is self-supporting in a stable state in the sample 100 accommodated in the sample container 2. In the rotor 1 that is self-supporting in the sample, the floating portion 202 is applied to the rotor 1 by the floating portion 1B so that the position of the buoyancy 202 is farther from the protruding portion 1C than the position of the center of gravity 201. The buoyancy is adjusted. A vector 202B of buoyancy applied to the buoyancy core 202 (buoyancy based on the specific gravity of the rotor 1 and the specific gravity of the rotor) is directed upward in a direction perpendicular to the liquid surface of the sample 100 and away from the liquid surface. . On the other hand, the vector 201 due to the gravity (mass of the rotor 1) applied to the center of gravity 201 is directed in the lower direction perpendicular to the liquid surface of the sample 100 and away from the liquid surface. When each of the vector 201B and the vector 202B is on the same straight line 150 perpendicular to the liquid surface of the sample 100, that is, on a straight line 150 passing through the center of gravity 201 and perpendicular to the liquid surface of the sample 100, the vector 201B and the vector 202B are parallel to the straight line 150. In this case, the sample 100 is self-supporting in a stable state. That is, in this embodiment, since the position of the buoyancy 202 in the rotor 1 is configured to be farther from the protrusion 1C than the position of the center of gravity 201, the rotation axis of the rotor 1 is The rotor 1 is self-supporting in the sample 100 by being held in the vertical direction.

  FIG. 3B shows a state in which the rotor 1 is tilted by some rocking (applying some force) in the sample 100 in which the sample container 2 is accommodated. In FIG. 3B, some force is applied to the rotor 1, and the direction of the straight line 150 perpendicular to the liquid surface of the sample 100 and the direction of the straight line 160 perpendicular to the upper surface of the rotor bottom plate 1A are at an angle θ. Is different. At this time, each of the vector 201B and the vector 202B does not exist on the same straight line 150 perpendicular to the liquid surface of the sample 100. That is, the vector 201B and the vector 202B are not on the same straight line 150 perpendicular to the liquid surface of the sample 100. In order to obtain a buoyancy equal to the gravity of the sample 100 corresponding to the volume of the sample 100 excluded from the portion of the rotor 1 submerged in water, the rotor 1 is tilted as shown in FIG. The position of the buoyancy 202 moves. That is, in this embodiment, since the position of the floating core 202 is configured to be farther from the protrusion 1C than the position of the center of gravity 201, the rotational axis of the rotor 1 is restored in the vertical direction. The rotor 1 itself has a restoring force to be caused.

  In the case described above, the rotational moment (torque) is applied to the rotor 1 so that each of the vector 201B and the vector 202B returns on the same straight line 150 perpendicular to the liquid surface of the sample 100 and the rotor 1 is in a stable state. Take it. This torque is applied to the rotor 1 in the same manner even when the rotor 1 is rotating while a torque for rotating the rotor 1 about the central axis is applied. As a result, the rotating shaft 11 is positioned on the same straight line as the straight line 150, the liquid surface of the sample 100 and the upper surface of the rotor bottom plate 1A are parallel, and the rotor for obtaining the viscosity of the sample 100 with high accuracy. The rotational speed of 1 can be obtained. Then, as the rotor 1 disposed in the sample 100 accommodated in the sample container 2 rotates, the sample 100 sandwiched between the rotor bottom plate 12 and the sample 100 has a shear flow having a predetermined shear rate. And a viscous torque is generated with respect to the rotation of the rotor 1 due to the shear stress based on the shear flow (described later).

  FIG. 4 is a conceptual view of the sample container 2 as viewed from the side in order to explain another arrangement of the rotor 1 in the sample 100 accommodated in the sample container 2. In FIG. 4, the floating portion 1B is disposed on the upper surface of the rotor bottom plate 1A, has a cylindrical shape with only an outer peripheral surface sealed at the top by a lid 1D, and the interior 300 is a space. The lid 1D is a disk with a thin resin. Due to the space in the interior 300, buoyancy corresponding to the specific gravity of the sample 100 is generated on the rotor 1. As the outer peripheral surface of the floating portion 1B, a cylindrical plate made of a resin plate or the like, or a cylinder formed by cutting a resin pipe perpendicular to the central axis and using the outer peripheral wall of the cut pipe is used. be able to.

Further, the floating portion 1B may be a cylinder in which the interior 300 is filled with another member, or a column having no interior space. In this case, it is not necessary to provide the lid 1D for the floating portion 1B.
When the viscosity measurement is performed with the rotor 1 completely submerged in the sample 100 as shown in FIG. 4, the sample 100 is in contact with the entire lower surface of the lid 1D and the entire lower surface of the sample container lid 21. The sample 100 is filled in the sample container 2. In the sample container 2, the sample 100 is filled in a space between the sample container main body 21 and the sample container lid 22. Thereby, along with the rotation of the rotor 1 arranged in the sample 100 accommodated in the sample container 2, shear flow occurs in the sample 100 sandwiched between the rotor bottom plate 12 and the lid 1D and the sample 100, A viscous torque is generated with respect to the rotation of the rotor 1 (described later).
At this time, in order to increase the measurement accuracy of the viscosity of the sample 100, the opposing distance between the lower surface of the rotor bottom plate 1A and the inner bottom surface of the sample container body 21, and the upper surface of the lid 1D and the lower surface of the sample container lid 21 are opposed. The distance is the same.

In this embodiment, about 60% of the weight of the rotor 1 is the mass of the member constituting the rotor bottom plate 1A, and the remaining about 40% of the weight of the rotor 1 is the mass of the member constituting the floating portion 1B. is there. When the weight of the rotor 1 is about 1.3 g (grams), the magnitude of gravity applied to the rotor 1 is 1.3 gram weight. Here, when the volume of the hollow portion inside the rotor 1 is about 0.8 cm ³ and the specific gravity of the sample is 1.0 g / cm ³ , the maximum buoyancy applied to the rotor 1 is 0.8 gram weight. is there. For this reason, the rotor 1 does not float completely in the sample 100 accommodated in the sample container 2, and as shown in each of FIG. 4 (a) and FIG. Is completely sunk.

  FIG. 4A shows a state where the rotor 1 is sinking in a stable state in the sample 100 accommodated in the sample container 2. In the rotor 1 that is self-supporting in the sample, the floating portion 202 is applied to the rotor 1 by the floating portion 1B so that the position of the buoyancy 202 is closer to the protruding portion 1C than the position of the center of gravity 201. The buoyancy is adjusted. A vector 202B of buoyancy applied to the buoyancy core 202 (buoyancy based on the specific gravity of the rotor 1 and the specific gravity of the rotor) is directed upward in a direction perpendicular to the liquid surface of the sample 100 and away from the liquid surface. . On the other hand, the vector 201 due to the gravity (mass of the rotor 1) applied to the center of gravity 201 is directed in the lower direction perpendicular to the liquid surface of the sample 100 and away from the liquid surface. When each of the vector 201B and the vector 202B is on the same straight line 150 perpendicular to the liquid surface of the sample 100, that is, on a straight line 150 passing through the center of gravity 201 and perpendicular to the liquid surface of the sample 100, the vector 201B and the vector 202B are parallel to the straight line 150. In this case, the sample 100 floats in a stable state in the sample 100.

  FIG. 4B shows a state in which the rotor 1 floats in an unstable state in the sample 100 accommodated in the sample container 2. In FIG. 4B, some force is applied to the rotor 1, and the direction of the straight line 150 perpendicular to the liquid surface of the sample 100 and the direction of the straight line 160 perpendicular to the upper surface of the rotor bottom plate 1A are at an angle θ. Is different. At this time, as in the case of FIG. 3B, the vectors 201 </ b> B and 202 </ b> B do not exist on the same straight line 150 perpendicular to the liquid surface of the sample 100.

  That is, the rotation moment (torque) is applied to the rotor 1 so that each of the vector 201B and the vector 202B returns on the same straight line 150 perpendicular to the liquid surface of the sample 100 and the rotor 1 is in a stable state. This torque is applied to the rotor 1 in the same manner even when the rotor 1 is rotating while a torque for rotating the rotor 1 about the central axis is applied. As a result, the rotating shaft 11 is positioned on the same straight line as the straight line 150, the liquid surface of the sample 100 and the upper surface of the rotor bottom plate 1A are parallel, and the rotor for obtaining the viscosity of the sample 100 with high accuracy. The rotational speed of 1 can be obtained.

  In FIG. 1, a sample container 2 filled with a sample 100 is provided on the upper surface of the sample stage 6. A magnet fixing base 7 to which the motor shaft 4 a of the motor 4 is connected is provided below the sample base 6 in parallel with the sample base 6. By rotating the motor shaft 4a of the motor 4, the magnet fixing base 7 is rotated. On the upper surface of the magnet fixing base 7, a first magnet 3_1 (third magnet 3_3) and a second magnet 3_2 (fourth magnet 3_4) are provided.

  The magnet fixing base 7 is a flat plate member that fixes a magnet that generates a rotating magnetic field. For example, the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 are fixedly provided on the upper surface of the magnet fixing base 7. The magnet fixing base 7 is disposed so as to be parallel to the rotor bottom plate 1A. Each of the first magnet 3_1 and the second magnet 3_3 is provided such that the south pole is in contact with the upper surface side of the magnet fixing base 7 and the north pole faces the rotor bottom plate 1A. Each of the second magnet 3_2 and the fourth magnet 3_4 is provided such that the N pole is in contact with the upper surface side of the magnet fixing base 7 and the S pole is opposed to the rotor bottom plate 1A.

  Therefore, each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet is arranged so that the magnetic poles having different polarities from the adjacent magnets face the lower surface of the sample container 2. In addition, each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet is a rectangular parallelepiped, and the upper surfaces thereof are arranged in parallel to each other so that the height of the upper surface is the same.

  FIG. 5 is a plan view showing a fixed state of a magnet provided to generate a rotating magnetic field in the magnet fixing base 7. FIG. 5A shows the arrangement of each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet. The first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 are alternately arranged symmetrically with respect to the rotation axis of the magnet fixing base 7. On the other hand, FIG. 5B shows the arrangement of each of the fifth magnet 3_5 and the sixth magnet 3_6.

  In the present embodiment, the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet are used, but any number of magnets may be used as long as a rotating magnetic field can be generated. That is, although not shown, a plurality of (N, N = 2n, n is an integer of n ≧ 1) small magnets are arranged along the rotation direction of the rotor bottom plate 1A of the rotor 1 in the sample container 2. The magnetic poles on the upper surface may be arranged so that N poles and S poles are alternated. Further, the magnet fixing base 7 may be arranged on the upper part of the sample container 2 so as to face the liquid surface of the sample 100 filled in the sample container 2 so that the upper surface of the permanent magnet becomes a horizontal plane.

Returning to FIG. 1, the sample stage 6 is a flat plate member that fixes the sample container 2 filled with the sample 100, and is arranged such that the upper surface is parallel to the upper surface of the magnet fixing table 7.
Thereby, the rotor 1 is obtained when the rotor bottom plate 1A, the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet rotate in the sample 100 inside the sample container 2. The upper surface of each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet is parallel to the plane formed.
From the arrangement of the sample table 6, the magnet fixing table 7, the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet, the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and Each of the fourth magnets can generate a magnetic field perpendicular to the rotor 1 in the sample container 2 (or a perpendicular magnetic field component).

The motor 4 is a drive mechanism that rotates the magnet fixing base 7 in the direction of the motor shaft 4 a perpendicular to the surface of the magnet fixing base 7, and is fixed so that the motor shaft 4 a is perpendicular to the upper surface of the magnet fixing base 7. Has been.
Further, in plan view, the rotating shaft 11 of the rotor 1 is disposed at a position where the rotor bottom plate 1A of the rotor 1 does not contact the inner wall of the sample container 2 and rotates in contact with the sample 100. The sample container 2 and the motor 4 are arranged.
That is, the sample container 2 and the motor 4 are arranged at a position where the center of the bottom surface of the sample container 2 and the axial direction of the motor shaft 4a of the motor 4 overlap in plan view.

Further, when a rotating magnetic field is applied to the rotor bottom plate 1A of the rotor 1 in the sample 100 filled in the sample container 2 and the rotating shaft 11 is rotated about the rotation center, the magnet fixing base 7 is rotated by the motor 4. Let Accordingly, each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet rotates, and a rotating magnetic field is applied to the rotor bottom plate 1A. At this time, the rotating shaft 11 of the rotor 1 may deviate from the center of the bottom surface of the sample container 2 depending on the application state of the rotating magnetic field to the rotor bottom plate 1A.
Here, in plan view, the area of the bottom portion inside the sample container 2 is made larger than the area of the rotor bottom plate 1A of the rotor 1. Thereby, even if the rotating shaft 11 of the rotor 1 is deviated from the center of the bottom surface of the sample container 2, it does not come into contact with the side wall inside the sample container 2. However, since the sample container 2 is made large, the amount of the sample 100 filled in the sample container 2 necessary for measuring the viscosity η increases.

  For this reason, as shown in each of FIGS. 3 and 4, in the present embodiment, a smooth groove (concave portion) 21 </ b> C is provided on a part of the inner bottom surface of the sample container main body 21. By providing this groove portion 21C, when the rotor 1 rotates, the protrusion 1C of the rotor bottom plate 1A of the rotor 1 (the convex portion which is the lower portion of the rotating shaft 11) contacts the center of the groove portion 21C. So that it is arranged by gravity. The rotor 1 rotates with the protrusion 1C of the rotor bottom plate 1A inserted into the groove 21C. For this reason, the distance between the lower surface of the rotor bottom plate 1A and the bottom surface inside the sample container main body 21 can be kept constant with high accuracy, and the shear rate of the rotor bottom plate 1A in the sample 100 can be stably maintained. The accuracy of the viscosity measurement of the sample 100 is improved.

  FIG. 6 is a diagram showing the relationship between the number of revolutions ΩM of the motor 4 and the number of revolutions ΩD of the rotor 1 in the corresponding standard sample in a plurality of standard samples having different viscosities η. In FIG. 6, the horizontal axis represents the rotational difference ΩMD (rotational speed ΩM−rotational speed ΩD) between the rotational speed ΩM and the rotational speed ΩD, and the vertical axis represents the rotational speed ΩD of the rotor 1. The viscosity η of each standard sample used here is different, for example, and is 0.5 (mPa · s) for sample A and 1.0 (mPa · s) for sample B. Then, from FIG. 6, a curve indicating the relationship between the rotation difference ΩMD and the rotation number ΩD for each standard sample having different viscosities η, that is, the correspondence between the gradient ΩD / ΩMD is obtained by the least square method or the like. This slope ΩMD / ΩD is proportional to the viscosity η of each standard sample.

  Returning to FIG. 1, the rotation detection sensor 5 is disposed at a position in the upper direction of the sample container 2 as a position where a mark provided at a detectable position of the rotor 1 in the sample 100 of the sample container 2 can be detected. The position in rotation of the mark (mark 30 provided on the upper surface of the side wall of each floating portion 1B in FIGS. 3 and 4) added to the rotor 1 is optically detected. That is, the rotation detection sensor 5 emits laser light from the light irradiating unit, makes reflected light from the mark 30 of the rotor 1 incident on the light receiving unit, and outputs a detection electric signal corresponding to the intensity of the incident light.

  Further, instead of the rotation detection sensor 5, an imaging device in which a lens and an imaging device such as a CCD (Charge Coupled Device) are added to the microscope is provided, and the mark added to the rotor 1 moves in the rotation of the rotor 1. A captured image obtained by enlarging the state is output, and the number of rotations (that is, the number of rotations of the mark of the rotor 1 and the mark (provided on the upper surface of the side wall of each floating portion 1B in FIGS. 3 and 4) is output from image processing. When the mark 30) rotates once, the number of turns may be detected as 1). Further, in the rotor 1, the mark may be added (arranged) to the detectable position on the upper surface of the rotor bottom plate 1A, and the rotational speed of the rotor 1 described above may be measured by the imaging device. .

Further, the inner surface of the rotor bottom plate 1A of the rotor 1 or the outer peripheral surface of the side wall of the floating portion 1B or the projection 1C is irradiated with laser, and the change in reflection and interference pattern due to the rotation is optically measured. A configuration may be adopted in which the number of rotations of the rotor 1 is detected.
Further, a part of the rotor bottom plate 1A or the floating portion 1B in the rotor 1 is replaced with a dielectric, and an electrode pair in which the rotor bottom plate 1A or the floating portion 1B is sandwiched between measurement electrodes is used as a magnet fixing base 7 shown in FIG. Place the capacitor in a position where it will not interfere with the rotation of the capacitor. Then, the rotation detection sensor 5 has a dielectric as a mark for detecting the rotation (for example, a mark 30 provided on the upper surface of the side wall of each floating portion 1B in FIGS. 3 and 4) between the electrodes disposed. When passing through, a detection electric signal is output. That is, when the dielectric as a mark passes between the electrodes, the rotation detection unit 81 detects a change in the capacitance of the capacitor constituted by the electrodes, and detects the number of times of the change in the capacitance during a predetermined period (for example, 1 second). In addition, the rotational speed of the rotor 110 may be detected.

Here, by rotating the magnet fixing base 7 with the motor 4, each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 rotates, and the rotating magnetic field is a magnetic field that varies with time. Is formed in a space on the upper surface of the magnet fixing base 7.
Torque is applied to the rotor bottom plate 1A of the rotor 1 by this rotating magnetic field, and the rotor 1 is rotated in the sample 100 in the sample container 2 to perform a constant speed rotation motion. A method for measuring the viscosity η of the sample 100 from the rotation speed in the sample 100 of the rotor 1 will be described below.

The viscosity measurement unit 8 includes a rotation detection unit 81, a viscosity detection unit 82, a rotating magnetic field control unit 83, a standard data storage unit 84, and a device control unit 85.
The rotation detection unit 81 detects the rotation of the rotor 1 based on the detection electric signal supplied from the rotation detection sensor 5, and determines the number of detections per unit time (for example, 1 second) as the number of rotations per unit time (rpm : Revolutions per minute), and output the rotation speed ΩD. In addition, the rotation detection unit 81 does not use the detection electric signal of the rotation detection sensor 5 in detection of the number of rotations of the rotor 1 but uses an image picked up by the image pickup device. A mark added to the rotor 1 may be detected from the image by image processing, and the rotation speed ΩD per unit time may be obtained. Further, when the capacitor configuration is used, the rotation detection unit 81 detects the capacitance change of the capacitor configured by the electrode pair based on the detection electric signal, and detects the number of times of the capacitance change in a predetermined period (for example, 1 second). Alternatively, the rotational speed ΩD of the rotor 1 may be detected.

  As in the case of the standard sample described above, the viscosity detector 82 obtains the slope ΩD / ΩMD (= ΩM−ΩD) of the sample 100 and obtains the reciprocal ΩMD / ΩD of this slope. At this time, the viscosity detection unit 82 controls the rotating magnetic field control unit 83 (described later) to rotate the motor 4 at a plurality of different rotation speeds ΩM, and sends a control signal to the rotation detection unit every time the number of rotations is changed. 81. The rotation detection unit 81 inputs the rotation speed ΩD of the rotor 1 in the sample 100 in the sample container 2 at the rotation speed ΩM from the rotation detection sensor 5 every time a control signal is supplied from the viscosity detection unit 82. Then, the rotation detection unit 81 outputs the detected rotation speed ΩD to the viscosity detection unit 82 corresponding to the control signal.

  Then, the viscosity detection unit 82 reads out the viscosity η (mPa · s) corresponding to the reciprocal ΩMD / ΩD of the sample 100 from the viscosity detection table stored in the standard data storage unit 84 (described later). Is output as the viscosity η (mPa · s). Here, when the empirical formula is stored in the standard data storage unit 84, the viscosity detection unit 82 reads the empirical formula from the standard data storage unit 84, and substitutes the inverse of the slope ΩMD / ΩD for this empirical formula. The viscosity η (mPa · s) of the sample 100 may be calculated and obtained.

  The rotating magnetic field control unit 83 performs rotation control on the motor 4 so that the motor 4 rotates at the set number of rotations. Thereby, the magnet fixing base 7 rotates via the motor shaft 4a, and the magnetic fields generated by the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 rotate and rotate. A rotating magnetic field for rotating the child 1 in the sample 100 at a constant speed is generated.

The standard data storage unit 84 stores a viscosity detection table indicating the correspondence between the viscosity η (mPa · s) obtained from the relationship diagram of FIG. 6 and the reciprocal of the slope ΩMD / ΩD.
This viscosity detection table is created as follows. As described with reference to FIG. 6, in the viscosity measuring apparatus of the present embodiment, a standard sample whose viscosity is known in advance is placed (filled) in the sample container 2, and the rotor 1 is placed in the standard sample. When the motor 4 is rotated at the rotation speed ΩM, the rotation speed ΩD of the rotor 1 corresponding to the rotation speed ΩM of each motor 4 is measured by the rotation detection unit 81 described above. The rotation speed ΩD is measured for the standard sample with respect to a plurality of standard samples having different viscosity η (samples whose viscosity η is known in advance).
Further, instead of the viscosity detection table, an empirical formula indicating the correspondence between the viscosity η (mPa · s) and the reciprocal of the slope ΩMD / ΩD may be stored.
The device control unit 85 controls the operation of each unit in the viscosity measurement unit 8.

FIG. 7 is a diagram showing the shear rate dependence of each sample (sample A and sample B) obtained from the relationship diagram shown in FIG. In FIG. 7, the horizontal axis shows the shear rate (Shere rate, 1 / s), and the vertical axis shows the viscosity (viscosity, mPa · s) of the sample.
In this figure, it is shown that the viscosity of each sample is dependent on the shear rate, but the change in viscosity is due to the influence of the inertia of the sample. Correction can be made using a standard sample.
Pure viscosity (viscosity) is 0.9 (mPa · s) at room temperature. From this, it can be seen that the present embodiment can detect a difference in viscosity with high accuracy even for a sample A or the like having a viscosity lower than pure.

Next, a method for applying rotational torque to the rotor bottom plate 1A of the rotor 1 will be described. In FIG. 1, the N pole and the fourth magnet 3_4 of the first magnet 3_1 and the S pole of the second magnet 3_2 and the fourth magnet 3_3 are perpendicular to a certain reference plane (a plane including the rotor bottom plate 1A). A magnetic field is generated. This reference plane is a reference two-dimensional plane composed of an x-axis and a y-axis, and the axial direction of the rotary shaft 11 of the rotor bottom plate 1A of the rotor 1 rotating on this two-dimensional plane is the z-axis.
Hereinafter, the z-axis component of the magnetic field at the reference two-dimensional plane or a point (x, y, z) in the vicinity thereof is shown as Bz (x, y).

As described above, since the magnetic field is perpendicular to the reference two-dimensional plane, it is assumed that the magnetic field does not depend on the z axis. However, depending on the z axis, there is no problem in the following description. In addition, if there is a magnetic field component perpendicular to the reference two-dimensional plane, even if there are other magnetic field components that are not perpendicular to the reference two-dimensional plane, the rotor 1 rotates relative to the rotor bottom plate 1A. Does not hinder the application of torque.
In the following description, the rotor bottom plate 1A is formed of metal, and the rotational torque applied to the rotor bottom plate 1A is calculated. Also, for convenience, orthogonal coordinates are initially adopted, the vertically upper side of the rotor bottom plate 1A is set to the + z direction, the rotor bottom plate 1A is raised in the xy plane, and the center of the rotor bottom plate 1A (rotation with the rotation shaft 11) is performed. The intersection point with the bottom plate 1A is the origin. Further, the rotating magnetic field generated by the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 as the magnet fixing base 7 rotates is expressed by the following equation (1).

In the above equation (1), r represents the distance from the rotation axis, B _z represents the magnetic field in the z-axis direction, B (r) represents the magnetic field in the rotational radius direction, ω represents the rotational angular velocity, and t is Time indicates n, the number of sets of magnets, and θ indicates the rotation angle of the magnet fixing base 7. In the case of the present embodiment shown in FIG. 1, n is 2 because there are two sets of magnets having N and S poles as the magnetic poles facing the sample stage 6.
An electric field E generated (induced) by the magnetic field B that varies with time is given by the following equation (2). The magnetic field B and the electric field E are vectors.

In this equation (2), it is assumed that the magnetic field B has a magnetic field B _z having only a z-direction component, but the following argument holds even if there are components other than the z-axis direction.
The current vector i (current vector of the induced current induced) flowing through the conductive disc-like rotor bottom plate 1A in the rotor 1 is i = σE, where σ is the conductivity. i and E are vectors. Since the divergence is “0” for the current vector i, div i = 0. Therefore, for the electric field E, there exists a vortex potential φ that satisfies the following expression (3).

In the above equation (3), E _x represents an electric field in the x-axis direction in the two-dimensional coordinate system, and E _y represents an electric field in the y-axis direction in the two-dimensional coordinate system.
The above equation (3) is substituted into equation (2) to obtain the following equation (4).

  The following equation (5) is obtained from the equations (2) and (4).

  When the expression (5) is expressed by a specific expression of the magnetic field, it is expressed as the following expression (6).

  In the above equation (6), B (r) represents the magnetic field in the radial direction of rotation, ω represents the rotational angular velocity, t represents time, n represents the number of magnet pairs, and θ represents the number of magnet fixing bases 7. The rotation angle is indicated, and φ indicates the vortex potential.

  From the above equation (6), the following equation (7) is obtained.

In the above equation (7), J _n (kr) represents a first-type Bessel function, k represents an integration variable for executing the integration of equation (7), r represents a rotation radius, and ω represents a rotation angular velocity. , T represents time, and θ represents the rotation angle of the magnet fixing base 7.
In the above equation (7), the coefficient A (k) is the Hankel transform coefficient of B (r) and is expressed by the following equation (8).

  The following description moves from a three-dimensional coordinate system to a cylindrical coordinate system. When the electric field Er in the radial direction and the electric field Eθ in the radial direction are respectively obtained from the electric field Ex and the electric field Ey obtained by the expression (3), they can be expressed as the following expression (9). In the equation (9), θ represents the rotation angle of the magnet fixing base 7, and r represents the rotation radius.

In the above equation (9), considering the Lorentz interaction between the electric field (the electric field based on the induced current) and the magnetic field, the total integral of the radial components of the Lorentz force is obviously zero due to symmetry.
The radial component is given by F _θ = σE _r B _z . This radial component is expressed by the following equation (10) by the equations (7) and (9). In equation (10), ω represents the rotational angular velocity, θ represents the rotational angle of the magnet fixing base 7, n represents the number of magnet pairs, and the coefficient A (k) represents the Hankel transformation coefficient of B (r). J _n (kr) represents the first type Bessel function, k represents an integration variable when executing the integration of Expression (7), and r represents the radius of rotation.

In the above equation (10), for the sake of simplicity, the radial distribution of the magnetic field can be approximated by a Bessel function. That is, when B (r) = B ₀ J _n (kr), the torque T applied to the rotor bottom plate 1A by the rotating magnetic field can be obtained by the following equation (11). Here, B ₀ indicates the strength of the magnetic field. In equation (11), n represents the number of magnet pairs, ω represents the rotational angular velocity, B ₀ represents an integration variable when performing the integration of equation (7), and J _n (kr) represents the first A seed Bessel function is shown.

As described above, it has been found that the torque T acts on the rotor bottom plate 1A of the rotor 1 by the rotating magnetic field. In the actual viscosity / elasticity measuring apparatus, the rotor 1 rotates in the sample 100 by the torque T acting on the rotor bottom plate 1A. Therefore, the rotational speed ΩM of the rotating magnetic field is the rotational speed ΩM of the magnetic field. The rotor 1 is replaced with a rotational speed difference ΩM−ΩD that is a difference from the rotational speed of the rotor bottom plate 1A.
As a result, the eddy current generated in the conductor of the rotor bottom plate 1A of the rotor 1 receives the rotation torque (torque T), whereby the rotation torque T is applied to the rotor bottom plate 1A of the rotor 1. become. As a result of the rotation torque being applied to the rotor bottom plate 1 </ b> A of the rotor 1, the rotor 1 rotates in the sample 100 in the direction in which the rotation torque T is applied.

Along with the rotation of the rotor bottom plate 1A, a viscous resistance torque due to shear flow corresponding to the viscosity η of the sample 100 is applied to the rotor bottom plate 1A and the floating portion 1B. Due to this viscous resistance torque, the rotational speed ΩD of the rotor 1 does not reach the rotational speed ΩM of the magnetic field by an amount proportional to the viscous resistance torque.
Therefore, the magnitude of the rotational torque T applied to the rotor bottom plate 1A of the rotor 1 is the difference between the rotational speed ΩM of the rotating magnetic field (similar to the rotational speed of the motor 4) and the rotational speed ΩD of the rotor 1. It will be proportional. That is, when the rotational speed ΩD of the rotor 1 becomes constant, the constant rotational speed ΩD has an inversely proportional relationship with the viscosity η of the sample 100.

As described above, the rotational torque T applied to the rotor bottom plate 1A of the rotor 1, the rotational speed ΩD of the rotor 1 rotating in the sample 100, and the radius of the rotor 1 (that is, the rotor bottom plate 1A Radius) r, the thickness (distance) between the rotor bottom plate 1A and the bottom of the inner surface of the sample container main body 21, and the thickness (distance) between the lid 1D of the floating portion 1B and the sample container lid 22; It can be seen that the viscosity η of the sample 100 can be obtained.
Here, in the measurement of the viscosity η of the sample 100, the rotational torque T applied to the rotor bottom plate 1A of the rotor 1 is shown in FIG. 6 which has already been explained using a standard sample whose viscosity η is known in advance. Thus, it is obtained as a function of the rotational speed difference ΩMD between the rotational speed ΩM of the rotating magnetic field and the rotational speed ΩD of the rotor 1.

Further, when the sample 100 is filled only in the space below the rotor bottom plate 1A, that is, when the sample 100 is filled only between the bottom of the inner surface of the sample container body 21 and the lower surface of the rotor bottom plate 1A, the sample 100 Contacts only the lower surface of the rotor bottom plate 1A. For this reason, when preparing the viscosity detection table shown in FIG. 6, it is necessary to measure the standard sample under the same conditions.
If the density of the sample 100 for measuring the viscosity η is known in advance, an appropriate sample having a uniform depth can be obtained when the sample 100 is inserted into the sample container 2 having a common size corresponding to the density of the sample 100. Weigh 100 with a balance. By this processing, the depth of the sample 100 put into the sample container 2 at the time of measurement can be made uniform for each sample 100 having different densities.

Here, the accuracy of the viscosity measurement in the viscosity / elasticity measuring apparatus of the present embodiment will be described. In the viscosity / elasticity measuring apparatus according to this embodiment, a known torque T is applied remotely to the rotor bottom plate 1A of the rotor 1 by a time-varying magnetic field (rotating magnetic field having a rotational speed ΩM), and the rotational speed ΩD. Is detected, and the viscosity η of the sample 100 as the target substance is measured.
The torque T applied to the rotor bottom plate 1A of the rotor 1 may be obtained by the above equation (11) from the magnitude of the applied magnetic field. Alternatively, the measurement may be performed in advance using a standard sample having a known viscosity η. The determination accuracy of the magnitude of the torque T obtained from this can be arbitrarily improved in principle, and can actually be determined with an accuracy of 0.1% or more.

On the other hand, the factors that determine the rotational speed ΩD of the rotor 1 include the protrusion 1C of the rotor bottom plate 1A of the rotor 1 and the groove inside the sample container body 21 in addition to the viscosity η of the sample 100 to be detected. The rotational torque _Tf by mechanical friction in a contact part with 21 C bottom face is mentioned. It has been verified theoretically and experimentally that the rotational torque T _f is of the level indicated by the following equation (12).

  In the above equation (12), M represents the weight of the rotor 1, ρ represents the specific gravity of the sample 100, V represents the volume of the portion of the rotor 1 that is immersed in the sample 100, g represents the gravitational acceleration, μ represents a dynamic friction coefficient between the protrusion 1C of the rotor bottom plate 1A and the bottom surface of the groove 21C inside the sample container main body 21, and Rc represents the lower portion 11e of the rotating shaft 11 of the rotor 1 and the bottom surface 21s of the sample container main body 21. The contact radius of the contact portion is shown.

In addition, the disk-shaped rotor bottom plate 1A having a radius R in the rotor 1 makes a rotation angle ω on the upper surface (the surface in contact with the lower surface of the rotor bottom plate 1A) with respect to the sample 100 having a thickness (depth) d, A torque T _VIS required to apply a strain with a rotational angular velocity of 0 on the lower surface (the surface in contact with the inner bottom surface of the sample container main body 21) is calculated by the following equation (13).

  In the above equation (13), R represents the rotation radius of the rotor 1, η represents the viscosity of the sample 100 as the detection target substance, and μ represents the protrusion 1C of the rotor bottom plate 1A of the rotor 1 and the sample container body. 21 indicates the dynamic friction coefficient with the bottom surface of the groove portion 21C inside 21, and d indicates the thickness of the sample 100 sandwiched between regions where the rotor bottom plate 1A of the rotor 1 and the internal bottom surface of the sample container body 21 face each other.

The coefficient α in the equation (13) is the required viscosity / elasticity measurement accuracy. For example, when the required measurement accuracy α is 1%, α = 0.01. If the rotational torque T _f obtained from the equation (12) is smaller than α times the torque T _VIS obtained from the equation (13), that is, if the following equation (14) is established, the required measurement accuracy α is obtained. be able to. The torque T _VIS due to the viscosity of the sample 100 dominates the torque T _f of mechanical friction due to the contact between the rotor 1 and the bottom surface 21s of the sample container body 21 by a factor of 1 / α or more, thereby achieving an accuracy α. Viscosity measurement is possible. Further, in order to stably rotate the rotor 1 in the sample 100, the rotor 1 is submerged in the sample 100, and the protrusion 1 </ b> C of the rotor bottom plate 1 </ b> A of the rotor 1 and the groove 21 </ b> C inside the sample container main body 21. It is necessary to make contact with the bottom. For this reason, the relationship between the gravity applied to the rotor 1 and the buoyancy in the equation (14) is M−ρV> 0.

The measurement accuracy α is about 10% in the conventional method, but more preferably about 1%. Furthermore, it is desired that about 0.1%, which is difficult accuracy with the conventional method, is obtained.
As described above, according to the present embodiment, the amount of the sample 100 that is the substance to be detected can be reduced as compared with the conventional measurement.
Further, according to the present embodiment, each of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 that generate the rotating magnetic field is arranged in the lower direction of the sample stage 6 on which the sample container 2 is disposed. It is possible to reduce the size of the viscosity / elasticity measuring apparatus as compared with the conventional one.

  Further, in FIG. 1, the combination of the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 is used as the magnet that generates the rotating magnetic field. In this case, the rotating magnetic field is generated by two sets of combinations in which two N poles and two S poles are alternately arranged in a plan view. On the other hand, according to the equation (11), the number of magnets for applying torque to the rotor bottom plate 1A of the rotor 1 may be arbitrarily set to one or more, for example, two square magnets in plan view. The S pole and the N pole may be arranged alternately.

In addition, the above-described magnet fixing base 7 is rotated, and a rotating magnetic field is generated using an electromagnet instead of generating a rotating magnetic field by the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4. It is good also as a structure.
FIG. 8 is a diagram showing an electromagnet in which a yoke 10 and teeth 10a, 10b, 10c and 10d protruding from the yoke 10 are arranged on a reference two-dimensional plane. A winding CL1 is wound around the teeth 10a and 10c in different winding directions, and similarly, a winding CL2 is wound around the teeth 10b and 10d in different winding directions to constitute an electromagnet.
Instead of generating a rotating magnetic field from the magnetic field emitted from the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 which are permanent magnets by rotating the magnet fixing base 7 by the motor 4 in FIG. You may generate | occur | produce a rotating magnetic field using the structure of the electromagnet shown in FIG. 8 mentioned above.

That is, a current is passed through the windings CL1 and CL2, a magnetic field perpendicular to the reference two-dimensional plane is generated, the direction of the flowing current is periodically changed, and a magnetic field perpendicular to the reference two-dimensional plane is generated. It may be rotated to form a rotating magnetic field. That is, each electromagnet is driven so that each of the electromagnets arranged on the circumference has a different polarity from the other adjacent electromagnets. When the electromagnet is driven, the rotating magnetic field may be generated by changing the polarity of each electromagnet with time.
In this case, the rotating magnetic field control unit 83 performs a process of causing a current to flow through the windings CL1 and CL2 in the electromagnet of FIG. 7 and periodically changing the direction of the flowing current to generate a rotating magnetic field.
As in the case where a magnet is already used, torque is applied to the rotor bottom plate 1A of the rotor 1 by this rotating magnetic field, and the rotational movement of the rotor bottom plate 1A around the rotation shaft 11 is performed in the sample 100. The viscosity η of the sample 100 is obtained.

Further, the rotating magnetic field control unit 83 may arbitrarily change the rotation period and the rotation direction of the rotating magnetic field to be applied to the rotor bottom plate 1A of the rotor 1.
For example, by periodically sweeping the rotation direction of the rotating magnetic field and the rotation speed, a rotational torque that periodically changes can be applied to the rotor 1.

FIG. 9 is a schematic diagram illustrating another configuration example of the shape of the rotor bottom plate in the rotor 1. 9, each of the sample container main body 21 and the sample container lid 22 is the same as that already described, but the cross section of the rotor bottom plate 1A ′ constituting the rotor 1 has a triangular shape. It has become. That is, the cross section of the rotor bottom plate 1A ′ is thick so that the opposing distance between the lower surface of the rotor bottom plate 1A ′ and the inner bottom surface of the sample container body 21 increases from the center toward the outer periphery in the radial direction. Is formed so that the thickness gradually decreases.
As a result, the thickness of the sample 100 sandwiched between the lower surface of the rotor bottom plate 1A ′ and the inner bottom surface of the sample container main body 201 increases in proportion to the distance from the rotation shaft 11 of the rotor 1. Thereby, uniform deformation of the shear rate can be realized everywhere in the sample 100 accommodated in the sample container main body 21. Therefore, the form of the rotor bottom surface 1A ′ is effective for measuring the viscosity and elasticity of a non-Newtonian fluid whose viscosity value varies depending on the shear rate.

Next, the measurement of elasticity using the viscosity / elasticity measuring apparatus according to the present embodiment will be described. This will be described with reference to the viscosity / elasticity measuring apparatus having the configuration shown in FIGS.
According to the present embodiment, instead of obtaining viscosity like a liquid, for a substance having an elastic modulus such as gel or rubber, or a substance such as a polymer solution in which an elastic modulus is generated by relaxation of viscosity, The viscosity and elastic modulus can be measured simultaneously by displacement from a stationary position when a constant torque is applied.

Here, the elastic modulus is a so-called spring constant and corresponds to a restoring force proportional to the rotational deformation of the sample 100.
Therefore, when there is elasticity in addition to viscosity, the restoring force due to the elastic modulus increases in proportion to the degree of strain. For this reason, after the rotation starts, the rotor 1 stops rotating at a rotation angle θ that balances the elastic force proportional to the spring constant of the sample and the rotational torque generated by the rotating magnetic field. By rotating the magnet fixing base 7 counterclockwise, the counterclockwise rotational torque is applied to the rotor 1 in the sample 100 as described above.

Then, the rotation of the floating rotor 1 stops at the position of the rotation angle θ where the rotational torque applied to the rotor 1 and the repulsive force due to elasticity balance.
Here, in the rotation detector 81, the motor 4 is rotated at a predetermined rotational speed ΩM and the position of the mark 30 of the rotor blade of the rotor 1 when the motor 4 is not rotating and the magnet fixing base 7 is stopped. Thereafter, the rotation angle θ is obtained from each captured image with the position of the mark 30 when the rotation is stopped. The elasticity can be obtained from this angle θ.

FIG. 10 is a diagram showing the relationship between the rotational speed ΩM (that is, rotational torque) of the motor 4 and the rotational angle θ at which the rotor 1 stops. In FIG. 10, the horizontal axis indicates the rotational speed ΩM of the motor 4, and the vertical axis indicates the rotation angle θ at which the rotor 1 stops.
That is, in the case of the viscosity / elasticity measuring apparatus shown in FIGS. 1 and 3, when the magnet fixing base 7 is rotated by the motor 4, the first magnet 3_1, the second magnet 3_2, which are arranged on the magnet fixing base 7, Each of the third magnet 3_3 and the fourth magnet 3_4 generates a rotating magnetic field corresponding to the rotation speed of the motor 4.

  Then, the rotating magnetic field control unit 83 changes the rotation speed of the motor 4 according to preset steps, obtains the rotation angle θ for each rotation speed, and obtains the relationship between the rotation speed ΩM and the rotation angle θ. The graph shown in FIG. Here, the above-described processing is performed on a plurality of standard samples whose elasticity is known in advance in order to create standard data used for the elasticity measurement of the sample 100 whose elasticity is unknown, similarly to the viscosity. Similarly to the creation of the viscosity standard data, the standard sample is put in the sample container 2 and the rotation angle θ described above is measured.

FIG. 11 is a diagram illustrating the relationship between elasticity and the ratio of the rotation speed and the rotation angle. In FIG. 11, the horizontal axis indicates elasticity (elastic modulus: Pa), and the vertical axis indicates a proportional coefficient between the rotational speed ΩM and the rotational angle θ. Here, the viscosity and the rotation angle θ are inversely proportional.
FIG. 11 shows standard data of elasticity used for elasticity measurement, which is created by associating the inclination (ratio between the rotational speed ΩM and the rotational angle θ) of each standard sample in FIG. 10 with the viscosity of the corresponding standard sample. is there.
In the actual measurement of the unknown elastic sample 100, the sample 100 to be measured is placed in the sample container 2, and the rotating magnetic field control unit 83 rotates the motor 4 at a preset rotation speed as in the case of the standard sample. .

Then, the rotation detection unit 81 obtains the rotation angle θ for each rotation speed and outputs it to the viscosity detection unit 82.
The viscosity detection unit 82 obtains a proportional coefficient between the rotation speed ΩM and the rotation angle θ supplied from the rotation detection unit 81, reads elasticity data corresponding to the proportional coefficient from the standard data in the standard data storage unit 84, The read data is output as the elasticity of the sample 100.

Moreover, it is also possible to measure elasticity and viscosity simultaneously by changing the rotational torque applied to the rotor bottom plate 1A of the rotor 1 with time. In this case, the magnet for generating the rotating magnetic field is constituted by the electromagnet shown in FIG.
For example, after applying an exciting current to the electromagnet and applying a predetermined rotational torque to the rotor bottom plate 1A of the rotor 1, the application of the exciting current is stopped and the rotation of the rotor 1 is stopped. Observe the condition.

At this time, the rotor 1 causes rotational vibration according to the elasticity of the sample 100 with which the rotor 1 is in contact. Here, the period and vibration time of rotational vibration are proportional to elasticity, and the attenuation rate of the amplitude of rotational vibration is proportional to viscosity.
Therefore, a rotating magnetic field is applied to the rotor bottom plate 1A of the rotor 1 for each of a plurality of standard samples whose viscosity and elasticity are known in advance, with the attenuation rate, period and vibration time of the rotation vibration. The standard data is prepared and stored in the standard data storage unit 84 in advance.

Next, when measuring a substance to be measured having actual unknown viscosity and elasticity, the viscosity detector 82 determines the amplitude attenuation rate, period, and vibration time of the sample 100 that is the substance to be measured as a rotor. 1, the viscosity corresponding to the measured attenuation rate of the amplitude and the elasticity corresponding to the period and the vibration time are read from the standard data in the standard data storage unit 84, respectively.
Then, the viscosity detector 82 outputs the viscosity and elasticity read from the standard data as the viscosity and elasticity of the sample 100 to be measured.
As described above, according to this embodiment, the viscosity and elasticity of the sample 100 can be simultaneously measured at the same time.

Further, by periodically sweeping the rotation direction of the rotating magnetic field applied to the rotor bottom plate 1A of the rotor 1 and the rotation torque (the rotational speed ΩM of the motor 4), the rotor bottom plate 1A of the rotor 1 Periodic rotational torque can be applied.
The amplitude and phase of the rotational vibration of the rotor 1 are observed from the captured image obtained by imaging the mark 30 of the rotor 1 while changing the period of sweeping the rotational direction and the rotational torque. It becomes possible to measure elasticity independently.
That is, the observation of this rotational vibration is to detect the damped vibration after the magnetic field is erased as a frequency spectrum, and is basically the same as the measurement of viscosity and elasticity after the magnetic field is erased. .

Next, a specific application example in the viscosity / elasticity measuring apparatus (mechanical property measuring apparatus) shown in FIG. 1 will be described.
The sample container main body 21 used was a glass petri dish having an inner diameter of 40 mm and an inner side wall height of 10 mm. Then, 5 mL of the sample 100 as the substance to be measured was placed in the sample container main body 21, and then the sample container main body 21 was sealed with the sample container lid 22. Here, for example, the temperature of the sample 100 was set to 20 ° C.
As standard samples whose viscosity is known in advance, two types of 0.5 (mPa · s) and 1.0 (mPa · s) were used as shown in FIG.

  Then, rotational torque was applied to the rotor bottom plate 1A of the rotor 1 on the surface of the standard sample, and the rotor 1 was rotated. In this case, the lower surface of the rotor bottom plate 1A is in contact with the sample 100. Here, the rotor bottom plate 1A is an aluminum plate having a diameter of 20 mm and a thickness of 1 mm, and an aluminum sphere having a diameter of 2 mm is attached to the bottom surface at the center of rotation of the disc as a protrusion 1C. A glass tube having an outer diameter of 20 mm, an inner diameter of 16 mm, and a length (height as a side wall) of 4 mm was used for the floating portion 1B.

Next, the rotating magnetic field control unit 83 drives the motor 4 to rotate the magnet fixing base 7.
As a result, the magnetic field perpendicular to the rotor bottom plate 1A of the rotor 1 generated by the first magnet 3_1, the second magnet 3_2, the third magnet 3_3, and the fourth magnet 3_4 is converted into the first magnet 3_1, the second magnet 3_2, A rotating magnetic field is applied to the rotor bottom plate 1A of the rotor 1 by rotating the three magnets 3_3 and the fourth magnet 3_4. Due to this rotating magnetic field, the rotor bottom plate 1A of the rotor 1 is rotated in the same direction as the rotating direction of the applied rotating magnetic field by applying a rotating torque.
And the rotation detection part 81 memorize | stores the moving image which the mark 30 of the rotor bottom plate 1A of the rotor 1 rotates which the rotation detection sensor (imaging element) images, for example in an internal storage part as a captured image, The rotational period of the mark 30 is obtained by image processing, and the rotational speed of the rotor 1 is obtained from the rotational period of the mark.

Each time the rotational speed ΩM of the motor 4 is changed, the corresponding rotational speed ΩD of the rotor 1 is obtained. As shown in FIG. 6, the rotational speed ΩD of the rotor 1 and the rotational speed ΩM for each standard sample having different viscosities. And the corresponding relationship with the difference of ΩM.
In FIG. 6, the relationship indicating the relationship between the rotational speed ΩD of the rotor 1 of each standard sample and the difference between the rotational speeds ΩM and ΩM is a straight line. For this reason, FIG. 6 shows that the viscosity can be obtained only from the relationship between the rotational speed of the rotor 1 and the rotational torque applied to the rotor 1.
As a result, it can be seen that the viscosity can be accurately measured by using the standard data.

Note that a program for realizing the function of the viscosity / elasticity measuring apparatus of FIG. 1 in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. Thus, processing for obtaining the viscosity of the sample may be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices.
The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Rotor 1A ... Rotor bottom plate 1A
DESCRIPTION OF SYMBOLS 1B ... Floating part 1C ... Protruding part 2 ... Sample container 4 ... Motor 5 ... Rotation detection sensor 6 ... Sample stand 7 ... Magnet fixing stand 8 ... Viscosity measuring part 11 ... Rotating shaft 21 ... Sample container main body 21C ... Groove part 22 ... Sample container Lid 30 ... Mark 3_1 ... 1st electromagnet 3_2 ... 2nd electromagnet 3_3 ... 3rd electromagnet 3_4 ... 4th electromagnet 81 ... Rotation detection part 82 ... Viscosity detection part 83 ... Rotating magnetic field control part 84 ... Standard data storage part 85 ... Apparatus control Part

Claims (9)

A rotor partly or entirely made of a conductive material, and having a protruding protrusion at the center of rotation at the lower part thereof;
A sample container in which a detection target substance for which viscosity is to be detected is placed, and the rotor is arranged in a state in which the protrusion comes into contact with the inner bottom of the inner surface in contact with the detection target substance;
A time-varying magnetic field is applied to the rotor, an induced current is induced in the rotor, and rotational torque is applied to the rotor by Lorentz interaction between the induced current and the magnetic field applied to the rotor. A rotation control unit for rotating
A rotation detector for detecting the rotation speed of the rotor;
A viscoelasticity detection unit that detects the viscosity and elasticity of the detection target substance in contact with the rotor according to the rotational speed of the rotor;
The viscosity / elasticity measuring apparatus, wherein a center of gravity of the rotor is closer to the protrusion than a buoyancy position caused by buoyancy generated corresponding to a portion of the rotor submerged in the detection target substance. The viscosity / elasticity measuring apparatus according to claim 1, wherein a radius of the rotor of the rotor is determined by the following equation.

The distance between the center of gravity position and the buoyancy position is set to be equal to or greater than a distance having a restoring force for holding the rotation axis in the vertical direction in the rotation of the rotor. The viscosity / elasticity measuring device described. A storage unit for storing standard data obtained by measuring in advance the relationship between the rotational torque applied to the rotor in a plurality of substances whose viscosity is known and the rotational speed of the rotor;
The viscosity / elasticity of the detection target substance is obtained by comparing the standard data with the relationship between the rotational torque and the rotation speed of the detection target substance detected by the viscosity detection unit. Item 4. The viscosity / elasticity measuring apparatus according to any one of Items 3 to 4. A mark is attached to the surface of the rotor,
The viscosity / elasticity measuring apparatus according to any one of claims 1 to 4, wherein the rotation detection unit detects the rotation number of the rotor by detecting the rotation of the mark. The number of rotations of the rotor is detected by irradiating the rotor of the rotor with a laser and optically measuring a change in reflected light or an interference pattern. The viscosity / elasticity measuring apparatus according to claim 4. The bottom of the inner surface of the sample container in contact with the rotor is formed in a smooth flat surface or a concave surface having a smooth curved surface. Elasticity measuring device. The rotor according to any one of claims 1 to 7, wherein the rotor is formed so as to be thinner in proportion to a distance from the rotation axis with respect to a diameter direction of the rotor. Viscosity / elasticity measuring device. Detecting a rotor containing a detection target substance whose viscosity and elasticity are to be detected in a sample container, partially or entirely made of a conductive material, and having a protruding protrusion at the center of rotation at the lower part thereof A process of placing the projection in contact with the target substance and in contact with the bottom of the inner surface thereof;
A time-varying magnetic field is applied to the rotor, an induced current is induced in the rotor of the rotor, and Lorentz interaction between the induced current and the magnetic field applied to the rotor causes the rotor to A process of rotating by applying rotational torque;
Detecting the rotational speed of the rotor;
From the buoyancy position due to the buoyancy generated corresponding to the portion of the rotor submerged in the detection target material, including the viscosity detection process of detecting the viscosity and elasticity of the detection target material in contact with the rotor by the number of rotations, The method of measuring viscosity and elasticity, wherein the center of gravity of the rotor is close to the protrusion.

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