JP2021063722A - Oscillatory viscometer - Google Patents

Abstract

To provide an oscillatory viscometer with which pressure drag is reduced and the occurrence of measurement errors is suppressed.SOLUTION: Provided is an oscillatory viscometer comprising: a pair of rod-like oscillators; a fulcrum unit for pivotably supporting the oscillator; a drive unit for causing the oscillator to oscillate and arranged on one axial side of the oscillator; and a diaphragm provided in the other axial side portion of the oscillator. An oscillator 3 is supported by a fulcrum unit 4 so that the length from the fulcrum unit 4 to a diaphragm 8 is shorter than the length from the fulcrum unit 4 to a drive unit 5, and the diaphragm 8 is connected to the oscillator 3 at a position somewhere between the fulcrum unit 4 and the other end of the oscillator 3, a principal surface 83 of the diaphragm 8 being arranged so as to be along the direction of oscillation.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vibrating viscometer that measures the viscosity of a viscous fluid.

Examples of the device for measuring the viscosity of a sample include various types such as a vibration viscometer and a rotary viscometer. In some conventional vibration viscometers, the entire device is suspended and supported via a holding portion arranged above the viscometer body. For example, "The entire viscometer is suspended and supported by a device body (not shown) via a holding portion 50, and a supporting member 52 is attached to the holding portion 50 via a leaf spring 51, and is attached to the tip of the supporting member 52. A sensitive plate 53 is formed, and each support member 52 is provided with an electromagnetic drive unit 54 for vibrating the sensitive plate 53, and the electromagnetic force generated in the electromagnetic drive unit 54 and the elasticity of the leaf spring 51 cause it. The sensitive plate 53 vibrates in the sample L. ”A vibrating viscometer can be mentioned. For example, as in Patent Document 1.

In the vibration type viscometer described in Patent Document 1, a frictional drag due to viscosity acts between the main surface of the sensitive plate 53 and the sample L, and the amplitude value of the sensitive plate 53 changes depending on the magnitude of the frictional drag. The vibration viscometer measures the viscosity of the sample based on the current value when the electromagnetic drive unit 54 is controlled so that the amplitude value of the sensitive plate 53 is constant.

Japanese Unexamined Patent Publication No. 2000-283907

However, in the conventional vibration viscometer, the support member is swung around the leaf spring as a fulcrum portion, and the sensitive plate is arranged at the position farthest from the fulcrum portion in the support member. In this case, as the length of the sensitive plate from the fulcrum portion of the vibrator to the sensitive plate becomes longer, the inclination of the main surface of the sensitive plate with respect to the vibration direction increases due to the bending of the vibrator. As a result, the sensitive plate has a problem that the pressure drag on the main surface increases and a measurement error due to the pressure drag occurs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration viscometer that reduces pressure drag and suppresses the occurrence of measurement error.

That is, the first invention comprises a pair of rod-shaped oscillators, a fulcrum portion that swingably supports the oscillators, and the like.
The vibration in a vibration vibrating meter including a drive unit that is arranged on one side of the vibrator in the axial direction and vibrates the vibrator and a vibrating plate provided on the other side of the vibrator in the axial direction. The child is supported by the fulcrum so that the length from the fulcrum to the vibrating plate is shorter than the length from the fulcrum to the driving portion, and the vibrating plate vibrates from the fulcrum. It is a vibration type vibrating meter which is connected to the vibrator at a position between the other end of the child and the main surface of the vibrating plate is arranged along the vibration direction.

In the second invention, the minimum moment of inertia of area related to the bending in the vibration direction from the fulcrum portion to the diaphragm in the diaphragm is from the maximum moment of inertia of area related to the bending in the vibration direction in the diaphragm. A large, vibrating vibrating meter.

A third invention is a vibrating viscometer in which the fulcrum portion is an elastically deformable plate-shaped member integrally formed with the vibrator and is fixed to the housing of the viscometer.

The fourth invention is a vibration viscometer in which a plurality of the vibration plates are arranged symmetrically with the axis of the vibrator as a symmetric line in the vibration direction view.

A fifth invention is a vibration viscometer having a shape in which the diaphragm has a top protruding in the vibration direction.

As the effect of the present invention, the following effects are exhibited.

In the first invention, the vibrator is supported by the fulcrum portion so that the length from the fulcrum portion to the diaphragm is shorter than the length from the fulcrum portion to the drive portion. Further, the diaphragm is connected to the vibrator at a position between the fulcrum portion and the other side end of the vibrator. Further, the main surface of the diaphragm is arranged along the vibration direction. As a result, the vibration viscometer prevents the vibrator from twisting and the main surface of the diaphragm from following the direction other than the vibration direction by increasing the rigidity of the vibrator. As a result, the pressure drag that causes the measurement error can be reduced.

In the second invention, the rigidity of the vibrator supporting the diaphragm is made higher than that of the diaphragm. As a result, the vibrating viscometer increases the rigidity of the vibrator against bending in the vibration direction, thereby preventing the vibrator from twisting and the main surface of the vibrating plate from being along a direction other than the vibration direction. As a result, the pressure drag that causes the measurement error can be reduced.

In the third invention, the oscillator is supported by a fulcrum formed integrally with the oscillator. As a result, in the vibration viscometer, the fulcrum portion and the vibrator are integrally formed to increase the rigidity of the fulcrum portion, thereby suppressing the twist of the vibrator. As a result, the pressure drag that causes the measurement error can be reduced.

In the fourth invention, the vibrator is arranged symmetrically with a plurality of diaphragms having the axis of the vibrator as a symmetric line in the vibration direction view. As a result, in the vibrating vibrating meter, since the diaphragm is arranged around the vibrator, the balance of the diaphragm with respect to the vibrator becomes even, the vibrator is twisted, and the main surface of the diaphragm is not in the vibration direction. Suppressed along the direction. As a result, the pressure drag that causes the measurement error can be reduced.

In the fifth invention, the diaphragm has a shape having a top protruding in the vibration direction. As a result, in the vibrating viscometer, the pressure drag of the diaphragm with respect to the vibrating direction is reduced. As a result, the pressure drag that causes the measurement error can be reduced.

FIG. 1 shows a front sectional view of the vibrating viscometer of the present invention. FIG. 2 shows a side view of the vibrating viscometer of the present invention. FIG. 3 shows a control block diagram of the vibrating viscometer of the present invention. FIG. 4 shows a schematic view in which the fulcrum portion of the vibrating viscometer of the present invention is elastically deformed. (A) shows a state before the fulcrum part is elastically deformed, and (B) shows a state where the fulcrum part is elastically deformed. FIG. 5 shows a schematic view of an arrangement mode of an oscillator with respect to a fulcrum in the vibrating viscometer of the present invention and the vibrating viscometer other than the present invention. (A) shows an embodiment in which the fulcrum portion is arranged on the upper side of the vibrator in the vibration type viscometer other than the present invention, and (B) shows the mode in which the fulcrum part is the vibrator in the vibration type viscometer of the present invention. The aspect which is arranged on the lower side is shown. FIG. 6 shows a schematic view in which a pressure drag force and a friction drag force are generated between the vibrating plate and the sample in the vibrating viscometer of the present invention and the vibrating viscometer other than the present invention. (A) shows a state in which pressure drag and friction drag are generated when the main surface of the viscometer does not follow the vibration direction in a viscometer other than the present invention, and (B) is the vibration type of the present invention. It shows the state where pressure drag and friction drag are generated when the main surface of the viscometer is along the vibration direction in the viscometer. FIG. 7 shows a schematic view of the presence or absence of inclination of the diaphragm based on the magnitude of the pressure drag according to the difference in the arrangement mode of the diaphragm. (A) shows an aspect when one diaphragm is attached to one oscillator, and (B) is line symmetry with the axis of the oscillator as a symmetric line with respect to one oscillator. The mode when two diaphragms are attached to is shown. FIG. 8 shows a schematic view illustrating that the magnitude of the pressure drag changes depending on whether or not the end face of the diaphragm has a top protruding in the vibration direction. (A) shows a mode in which the end face of the diaphragm does not have a top protruding in the vibration direction, and (B) and (C) show a mode in which the end face of the diaphragm has a top protruding in the vibration direction. ..

First, the vibration viscometer 1 which is an embodiment of the vibration viscometer according to the present invention will be described with reference to FIGS. 1 and 2. In the following, the upper side (“one side in the axial direction of the vibrator” in the scope of the patent claim) means the drive unit 5 side of the vibrator 3 in the vibration viscometer 1, and the lower side (patent claim). The “other side in the axial direction of the oscillator”) in the range means the vibrating plate 8 side in the vibrating viscometer 1. Further, the "vibration direction" means a direction substantially orthogonal to the axes of the adjacent vibrators 3.

As shown in FIGS. 1 and 2, the viscometer 1 of the present invention is, for example, an apparatus for measuring the viscosity of a sample (liquid, or a mixture of liquid and gas) stored in a container. The viscometer 1 in the present embodiment includes a viscometer main body 2, a pair of oscillators 3, a fulcrum unit 4, a drive unit 5, a displacement sensor 6, a control unit 7, and a diaphragm 8. ..

The viscometer main body 2, which is the housing of the vibrating viscometer 1, is made of stainless steel and has an overall columnar shape, and has an opening on the lower side. A pair of oscillators 3, a fulcrum portion 4, a drive portion 5, and a displacement sensor 6 are housed inside the viscometer main body 2. The shape of the viscometer main body 2 is not limited to a columnar shape, and may be a rectangular parallelepiped or the like. The material of the viscometer main body 2 is not limited to metal such as stainless steel, but may be synthetic resin, ceramics, or a composite material thereof.

The oscillator 3 is a member that vibrates the diaphragm 8. The oscillator 3 is made of stainless steel and is formed in a columnar shape as a whole. The oscillator 3 is composed of an upper oscillator 31 and a lower oscillator 32. In the vibrator 3, a fulcrum portion 4 is arranged between the upper tip of the lower vibrator 32 and the lower tip of the upper vibrator 31. Inside the viscometer main body 2, two oscillators 3 are arranged so as to be adjacent to each other as a pair of oscillators 3. The pair of oscillators 3 are arranged so that their axes are parallel to each other.

The shape of the vibrator 3 is not limited to a columnar shape, and may be an elliptical shape or a polygonal shape in cross section. The material of the vibrator 3 is not limited to a metal such as stainless steel, but may be a synthetic resin, a ceramic, or a composite material thereof.

The fulcrum portion 4 is a member that swingably supports the pair of oscillators 3. The fulcrum portion 4 is a stainless steel circular plate-shaped member. The fulcrum portion 4 is formed in substantially the same shape as the opening of the viscometer main body 2. The fulcrum portion 4 is fixed to the viscometer main body 2 so as to cover the opening on the lower side of the viscometer main body 2. The lower end of the upper oscillator 31 is connected to the inner (upper side) plate surface of the viscometer main body 2 at the fulcrum portion 4. The upper end of the lower oscillator 32 is connected to the outer (lower) plate surface of the viscometer main body 2 of the fulcrum portion 4. That is, in the fulcrum portion 4, the upper oscillator 31 and the lower oscillator 32 are integrally formed. The fulcrum portion 4 supports the integrally formed upper oscillator 31 and the lower oscillator 32. Further, the fulcrum portion 4 is formed so as to be elastically deformable so that the swinging motion of the upper oscillator 31 driven by the drive portion 5 is transmitted to the lower oscillator 32. The fulcrum portion 4 is formed, for example, with a plate thickness of 1.5 mm or more and 2.0 mm or less. The fulcrum portion 4 applies an elastic force to the pair of oscillators 3 so that the axes of the pair of oscillators 3 are in a neutral position parallel to each other. In this way, the fulcrum portion 4 is integrally formed with the viscometer main body 2, the upper side oscillator 31, and the lower side oscillator 32, thereby improving the rigidity of the fulcrum portion 4 of the oscillator 3. ..

In the vibrating viscometer 1 of the present embodiment, the opening on the lower side of the viscometer main body 2 does not have to be completely covered by the fulcrum portion 4, and may be partially opened. Further, in the present embodiment, the material of the fulcrum portion 4 is made of a metal such as stainless steel, but may be made of a synthetic resin or a composite material thereof.

The drive unit 5 is an actuator that vibrates a pair of oscillators 3 by an electromagnetic force. The drive unit 5 employs a moving magnet system, and is composed of an electromagnetic coil and a ferrite magnet which is a permanent magnet. The electromagnetic coil is provided in the viscometer main body 2. The electromagnetic coil is arranged between the pair of oscillators 3. Ferrite magnets are provided at the upper end portions of the pair of oscillators 3, respectively. The drive unit 5 generates an electromagnetic force when a current from the control unit 7 is applied to the electromagnetic coil. The drive unit 5 is a drive force that swings the upper end portions of the pair of oscillators 3 in a direction in which the ferrite magnets arranged in the vicinity of the electromagnetic coil are attracted to the electromagnetic coil by an electromagnetic force. (It means the exciting force. The same shall apply hereinafter.) Is generated. The driving unit 5 swings the vibrator 3 to a position where the upper end portions of the pair of vibrators 3 are close to each other by the driving force.

The displacement sensor 6 detects the amplitude value of the vibrator 3. The displacement sensor 6 is arranged on the upper side inside the viscometer main body 2.

The control unit 7 is a device that controls the vibrating viscometer 1. The control unit 7 may actually have a configuration in which a CPU, ROM, RAM, HDD, etc. are connected by a bus, or may have a configuration including a one-chip LSI or the like. The control unit 7 includes an amplifier that supplies a current to the drive unit 5. The control unit 7 stores various programs and data for controlling the operation of the drive unit 5, the displacement sensor 6, and the like.

The control unit 7 is connected to the drive unit 5 and can supply a current to the drive unit 5.

The control unit 7 is connected to the displacement sensor 6 and can acquire the amplitude value of the vibrator 3 from the displacement sensor 6.

The control unit 7 can control the current to the drive unit 5 so that the amplitude value acquired from the displacement sensor 6 becomes the target amplitude value.

The diaphragm 8 causes friction with the sample in order to measure the viscosity of the sample. The diaphragm 8 is bent so as to form an L-shaped short portion 81 and a long portion 82. In the long portion 82 of the diaphragm 8, the main surface 83 (thin ink portion), which is the surface having the largest area, and the end surface 84, which is the other surface, are each formed in a flat shape. The short-sized portion 81 of the diaphragm 8 is connected to the diaphragm 8 at an arbitrary position between the fulcrum portion 4 and the tip of the lower vibrator 32. The long portion 82 of the diaphragm 8 extends downward along the axial direction of the vibrator 3. The diaphragm 8 is arranged so that the main surface 83 is along in a direction orthogonal to each other with respect to the axes of the pair of vibrators 3.

In the vibrating viscometer 1 configured in this way, the rigidity of the fulcrum portion 4 of the vibrator 3 is improved by integrally forming the upper oscillator 31 and the lower oscillator 32 at the fulcrum portion 4. I'm letting you. Further, the vibrating viscometer 1 attracts the upper end portions of the pair of oscillators 3 to close positions close to each other by generating an electromagnetic force in the driving unit 5. Further, the vibrating viscometer 1 eliminates the electromagnetic force of the drive unit 5, so that the pair of oscillators 3 attracted to each other are placed in a neutral position where the axes of the pair of oscillators 3 are parallel to each other by the elastic force of the fulcrum portion 4. Move to. As a result, the vibrating viscometer 1 vibrates the pair of diaphragms 8 provided at the lower end of the vibrator 3 in opposite phases, with the same frequency and the same amplitude.

The operation mode of the vibrating viscometer 1 according to the present invention will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, the vibration viscometer 1 of the present embodiment is controlled based on the control unit 7, the drive unit 5, and the displacement sensor 6.

As shown in FIG. 4A, the control unit 7 supplies a current to the drive unit 5 so that the diaphragm 8 immersed in the sample vibrates at the target amplitude value. The drive unit 5 attracts the ferrite magnet provided in the vibrator 3 by the electromagnetic force generated from the electromagnetic coil.

As shown in FIG. 4B, the drive unit 5 vibrates the pair of oscillators 3 from the neutral position to the close position. Next, the control unit 7 stops the supply of current to the drive unit 5. The drive unit 5 loses the force for attracting the ferrite magnet provided on the vibrator 3. As a result, the pair of oscillators 3 are moved to the neutral position by the elastic force of the fulcrum portion 4. Next, the control unit 7 supplies a current to the drive unit 5 again. By repeating the above process, in the vibrating viscometer 1, the pair of oscillators 3 vibrate in opposite phases, with the same frequency and the same amplitude. At this time, the vibration viscometer 1 detects the actual amplitude value of the vibrator 3 by the displacement sensor 6. The control unit 7 acquires the actual amplitude value detected by the displacement sensor 6.

The control unit 7 compares the acquired actual amplitude value with the target amplitude value. When the actual amplitude value is smaller than the target amplitude value (target amplitude value> actual amplitude value), the control unit 7 increases the current value supplied to the drive unit 5 in order to increase the amplitude value to the target amplitude value.

When the actual amplitude value is larger than the target amplitude value (actual amplitude value> target amplitude value), the control unit 7 reduces the current supplied to the drive unit 5 in order to reduce the amplitude value to the target amplitude value.

The control unit 7 controls the current value supplied to the drive unit 5 so that the actual amplitude value detected by the displacement sensor 6 converges to the target amplitude value. The control unit 7 calculates the viscosity of the sample from the current value when the difference between the actual amplitude value and the target amplitude value is within a predetermined range.

The vibrating viscometer 1 measures the viscosity of the fluid based on the frictional drag force F1 acting on the diaphragm 8 when the diaphragm 8 is vibrated in the fluid. At this time, a pressure drag force F2 acts on the diaphragm 8 in addition to the friction drag force F1. The "friction drag force F1" is a resistance force due to friction acting between the diaphragm 8 vibrating in the fluid and the fluid. That is, it is a resistance force due to shear stress acting on the surface of the diaphragm 8. The friction drag F1 acts in the direction of suppressing the vibration of the diaphragm 8 (the direction opposite to the vibration direction). The frictional drag force F1 increases as the viscosity of the fluid increases. That is, the friction drag F1 changes the amplitude value of the diaphragm 8 according to the viscosity of the fluid.

Further, the "pressure drag force F2" is a resistance force due to the pressure acting on the surface (for example, the end surface 84) of the diaphragm 8. The pressure drag force F2 acts in the direction of suppressing the vibration of the diaphragm 8 (the direction opposite to the vibration direction). The pressure drag F2 increases as the density of the fluid and the area of the surface on which the pressure of the diaphragm 8 acts increases. That is, the pressure drag F2 changes the amplitude value of the diaphragm 8 according to the density of the fluid and the area of the diaphragm 8 on which the pressure acts.

The vibrating viscometer 1 vibrates the diaphragm 8 at a target amplitude value in a fluid sample. On the main surface 83 of the diaphragm 8, a friction drag force F1 acting in a direction of suppressing the vibration of the diaphragm 8 is generated. The actual amplitude value of the diaphragm 8 becomes smaller than the target amplitude value of the diaphragm 8 due to the frictional drag force F1. Further, a pressure drag force F2 acting in a direction of suppressing the vibration of the diaphragm 8 is generated on the end surface 84 of the diaphragm 8. The actual amplitude value of the diaphragm 8 is further reduced by the pressure drag force F2. The vibrating viscometer 1 increases the current supplied to the drive unit 5 in order to set the actual amplitude value of the diaphragm 8 to the target amplitude value. The oscillating viscometer 1 calculates the viscosity of the sample from the increased current value. As described above, the measured value of the vibration viscometer 1 includes a measured value based on the friction drag force F1 that indirectly represents the viscosity of the sample and a measured value based on the pressure drag force F2 that is not related to the measurement of the viscosity of the sample. It has been. Therefore, in order to suppress the pressure drag force F2 that causes the viscosity measurement error, the vibration type viscometer 1 needs to reduce the area of the surface that is not along the vibration direction (not parallel) where the pressure drag force F2 is likely to occur. ..

As shown in FIG. 5A, in the vibration viscometer 1, the fulcrum portion 4 is arranged between the lower side oscillator 32 and the upper side oscillator 31. Then, the length (M1) of the vibrator 3 from the fulcrum portion 4 to the diaphragm 8 connected to the lower vibrator 32 is shorter than the length (M2) from the fulcrum portion 4 to the drive portion 5. As described above, it is supported by the fulcrum portion 4.

In the vibration type vibrating meter 1, the vibrator 3 is supported by the upper end portion, and the length from the fulcrum portion 4 to the diaphragm 8 (M1) is larger than the length from the fulcrum portion 4 to the drive portion 5 (M2). Compared to a long vibrating vibrating meter (see FIG. 5B), the rigidity of the lower oscillator 32 supporting the diaphragm 8 is increased.

Further, the bending deformation in the vibration direction from the fulcrum portion 4 to the diaphragm 8 in the vibrator 3 and the bending deformation in the vibration direction in the diaphragm 8 depend on the cross-sectional secondary moments of the vibrator 3 and the diaphragm 8. To do. In the vibrating viscometer 1 of the present embodiment, the minimum cross-sectional secondary moment relating to bending in the vibration direction from the fulcrum portion 4 to the diaphragm 8 in the vibrator 3 is the maximum cross section 2 relating to bending in the vibration direction in the diaphragm 8. It is set to be larger than the next moment. With this configuration, in the vibrating viscometer 1, the lower oscillator 32 supporting the diaphragm 8 has a higher rigidity than the diaphragm 8.

In this way, the vibrating vibrating meter 1 supports the pair of vibrators 3 by the fulcrum portion 4 at a position close to the vibrating plate 8 and supports the pair of vibrators 3 by utilizing elastic deformation. Since the rigidity of the pair of vibrators 3 is improved, it is possible to prevent the main surface 83 of the vibrating plate 8 from tilting and vibrating in a direction other than the vibrating direction when the vibrating plate 8 vibrates. As a result, in the vibrating viscometer 1, the pressure drag force F2 is unlikely to be generated on the main surface 83 of the diaphragm 8.

As shown in FIG. 6 (A), when the main surface of the diaphragm is not along the vibration direction (not parallel) and is moved (vibrated) in the direction of the whitewashed arrow, the sample is the main diaphragm. A flow that moves along the surface and a flow that collides with the end surface of the diaphragm and the main surface of the diaphragm facing the vibration direction are generated. On the main surface of the diaphragm, a frictional drag force F1 due to the sample flowing along the main surface is generated. On the other hand, a pressure drag force F2 due to the colliding sample is generated on the end surface of the diaphragm and the main surface of the diaphragm facing the vibration direction. In this case, the measured viscosity includes a measurement error based on the pressure drag F2 generated on the end face and the main surface which occupies a large proportion in the diaphragm.

As shown in FIG. 6B, in the vibrating viscometer 1 of the present invention, the rigidity of the pair of vibrators 3 is improved, so that the main surface 83 of the diaphragm 8 is white in the vibration direction. It is moved in the direction of the fill arrow. In this case, the sample has a flow that moves along the main surface 83 of the diaphragm 8 and a flow that collides with the end surface 84 of the diaphragm 8. On the main surface 83 of the diaphragm 8, a frictional drag force F1 due to the sample flowing along the main surface 83 is generated. On the other hand, a pressure drag force F2 due to the colliding sample is generated on the end surface 84 of the diaphragm 8. In this case, since the measured viscosity includes only the measurement error based on the pressure drag force F2 generated on the end face 84 which occupies only a small proportion in the diaphragm 8, the main surface 83 of the diaphragm 8 is along the vibration direction. Measurement error is suppressed compared to the absence state.

The vibrating viscometer 1 of the present embodiment is provided one for each vibrator 3, but as described below, two or more diaphragms for one vibrator 3 are provided. 8 may be provided.

As shown in FIG. 7A, when one vibrating plate 8 is provided at a position offset by an offset amount X1 from the axis of the vibrator 3 with respect to one vibrator 3, the vibrator 3 is provided with one vibrating plate 8. A moment around the axis of the vibrator 3 is generated by the pressure drag force F2 applied to the vibrating plate 8 at the position of the offset amount X1. The main surface 83 of the diaphragm 8 is moved in the direction of the white-painted arrow without following the vibration direction due to the moment. As a result, in the diaphragm 8, a pressure drag force F2 is generated on the main surface 83 in addition to the end surface 84.

As shown in FIG. 7B, when the oscillators 3 are provided on both sides of one oscillator 3 with the axis of the oscillator 3 sandwiched between them and at positions offset by the offset amount X2, the oscillators 3 In No. 3, a clockwise moment and a counterclockwise moment around the axis of the vibrator 3 are generated by the pressure drag force F2 applied to the vibrating plate 8. The two diaphragms 8 are arranged so as to be line-symmetric with respect to the axis of one vibrator 3 in the vibration direction view. Therefore, the clockwise moment and the counterclockwise moment applied to the vibrator 3 cancel each other out in the opposite directions and with the same magnitude. The main surface 83 of the diaphragm 8 is moved in the direction of the white-painted arrow in a state along the vibration direction. As a result, in the diaphragm 8, the main surface 83 vibrates along the vibration direction, so that the pressure drag force F2 is generated only on the end surface 84. In this way, the vibration type vibrating meter 1 is arranged line-symmetrically so that the balance of the diaphragm 8 is even with respect to the axis of the vibrator 3 in the vibration direction view, so that the main surface 83 of the diaphragm 8 is formed. It is suppressed to follow a direction other than the vibration direction, and the generation of the pressure drag force F2 which causes a measurement error is reduced.

As shown in FIG. 8, the end surface 84 of the diaphragm 8 is not limited to a flat shape, but has a shape having a top T protruding in the vibration direction, for example, a curved surface shape having a top shape, an inclined surface shape, a pointed shape, or the like. The shape may be such that the pressure drag of the diaphragm 8 with respect to the vibration direction is reduced.

As shown in FIG. 8A, the end surface 84 of the diaphragm 8 does not have a top protruding in the vibration direction and is flat. When the diaphragm 8 having the flat end surface 84 is moved (vibrated) in the direction of the white-painted arrow, the sample has a flow that collides with the end surface 84 of the diaphragm 8. A pressure drag F2 due to the colliding sample is generated on the end face 84. Since the entire surface of the end face 84 faces the flow of the sample, a pressure drag force F2 is generated due to the sample colliding with the entire surface of the end face 84.

The end surface 84 of the diaphragm 8 in FIGS. 8 (B) and 8 (C) includes a top portion T projecting in the vibration direction. As shown in FIG. 8B, the end surface 84 of the diaphragm 8 has a curved surface shape. When the diaphragm 8 having the curved end face 84 is moved (vibrated) in the direction of the white-painted arrow, a pressure drag force F2 due to the colliding sample is generated on the end face 84. Since the end face 84 faces the flow of the sample at an angle corresponding to the curvature of the end face 84, the sample collides with the sample at an angle corresponding to the curvature of the end face 84. That is, a pressure drag force F2 is generated on the end face 84 due to the component force according to the collision angle. Therefore, the pressure drag force F2 generated on the curved end face 84 is smaller than the pressure drag force F2 generated on the flat end face 84.

As shown in FIG. 8C, the end surface 84 of the diaphragm 8 has an inclined surface shape. When the diaphragm 8 having the inclined end face 84 is moved (vibrated) in the direction of the white-painted arrow, a pressure drag force F2 due to the colliding sample is generated on the end face 84 of the diaphragm 8. Since the end face 84 faces the flow of the sample with an inclination angle of the end face 84, the samples collide with each other at the inclination angle of the end face 84. That is, a pressure drag force F2 is generated on the end face 84 due to the component force according to the collision angle. Therefore, the pressure drag force F2 generated on the inclined end face 84 is smaller than the pressure drag force F2 generated on the flat end face 84.

From the above, when the amplitude value of the diaphragm 8 is constant, the magnitude of the frictional drag force F1 is the same for the diaphragm 8 of FIG. 8 (A), the diaphragm 8 of FIG. 8 (B), and the diaphragm 8 of FIG. 8 (C). On the other hand, the magnitude of the pressure drag force F2 is larger in the diaphragm 8 of FIG. 8 (A) than in the diaphragm 8 of FIGS. 8 (B) and 8 (C). As described above, the vibration type viscometer 1 can suppress the pressure drag force F2 generated on the end face 84 by providing the top portion T protruding in the vibration direction on the end face 84 where the pressure drag force F2 is generated.

The diaphragm 8 of the present embodiment is formed in an L-shape in a front view and a rectangular shape in a plan view, but is not limited to this, and may be a circular shape in a plan view. Further, in the vibrating viscometer 1 of the present embodiment, the pair of vibrators 3 and the diaphragm 8 are both immersed in the sample at the time of measurement, but only the diaphragm 8 may be immersed.

The types of samples measured by the vibration viscometer 1 of the present embodiment include, for example, "Newtonian fluid" such as water, saline solution, alcohol, and general solvent, as well as an aqueous solution of starch, running sand, and a viscosity slurry. Examples include "non-Newtonian fluids" including dilatant fluids, colloidal solutions, polymer solutions, pseudoplastic fluids such as emulsions, bingham fluids such as margarine, tomato ketchup, and egg white, and thixotropies such as solder paste, grease, and printing ink. ..

The above-described embodiment only shows a typical embodiment, and can be variously modified and implemented within a range that does not deviate from the gist of one embodiment. It goes without saying that it can be carried out in various forms, and the scope of the present invention is indicated by the description of the claims, and further, the equal meaning described in the claims, and all within the scope. Including changes.

1 Vibration type viscometer 2 Viscometer body 3 Oscillator 4 Supporting point 5 Drive part 6 Displacement sensor 7 Control part 8 Vibrating plate

Claims (5)

A pair of rod-shaped oscillators and
A fulcrum that swingably supports the oscillator and
A drive unit that is arranged on one side of the oscillator in the axial direction and vibrates the oscillator,
In a vibrating viscometer including a diaphragm provided on the other side portion in the axial direction of the vibrator.
The vibrator is supported by the fulcrum portion so that the length from the fulcrum portion to the diaphragm is shorter than the length from the fulcrum portion to the drive portion.
A vibrating vibrating meter in which the diaphragm is connected to the vibrator at a position between the fulcrum and the other end of the vibrator, and the main surface of the diaphragm is arranged along the vibration direction. According to claim 1, the minimum moment of inertia of area related to bending in the vibration direction from the fulcrum portion to the diaphragm in the vibrator is larger than the maximum moment of inertia of area related to bending in the vibration direction of the diaphragm. The vibrating vibrating meter described. The vibrating viscometer according to claim 1 or 2, wherein the fulcrum portion is an elastically deformable plate-shaped member integrally formed with the vibrator and is fixed to the housing of the viscometer. The vibrating viscometer according to any one of claims 1 to 3, wherein the vibrator is arranged symmetrically with a plurality of the vibration plates having the axis of the vibrator as a line of symmetry in the direction of vibration. The vibrating viscometer according to any one of claims 1 to 4, wherein the diaphragm has a shape having a top protruding in the vibration direction.

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