JPH06109612A - Rheology measuring device - Google Patents

Abstract

PURPOSE: To obtain a rheology measuring instrument provided with the lower assembly of a spring chamber or another (for example, a conical plate) and an electromagnetic converter, a flexible torsion spring, and a stone-pin bearing mechanism related to the lower assembly. CONSTITUTION: A rheology measuring instrument provided with a chamber 12 driven by means of a motor 24, a concentric spindle 14 which is constituted in an attachable/detachable state for exchanging a fluid and can be reinserted between a motor driving device and a converter 30, and a detecting shaft 26 utilizing a flexible fixture 36 and a stone-pin fixing mechanism 26A is precisely positioned repetitively in both the radial and axial directions. At the time of reassembling the measuring instrument, a fluid is made to be easily held for cleaning and operation by providing a wide torque range from a low torque to a high torque with high responsiveness and reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a measuring device for measuring rheological properties of fluids including single liquids and mixtures, slurries, suspensions, gels, clays and finely divided solids, which is precise and repeatable. The present invention relates to a rheology measuring device characterized in that it is calibrated easily and easily, the device to be measured is loaded with a fluid to be measured, and the position is adjusted through repeated cycles of measuring and exchanging the fluid. Further, the present invention is characterized in that it has a high precision that conforms to the above-mentioned measurement standard.

Some of these features are accomplished by a spindle chamber subassembly that, as a whole, is precisely radially and axially positioned within the device, and is readily removable to accommodate other characteristics described above. To be done.

[0003]

BACKGROUND OF THE INVENTION Practical rheology measuring devices (should be distinguished from viscosity indicators) measure the flow properties of fluid composition, behavior over time, homogeneity, plasticity, yield point, viscosity and these properties. As a whole, the driven member (usually the spindle) is connected to another member (usually the spindle) through the fluid.
It is measured as the shear response when driving a cylinder that is concentric to the spindle and has a narrow air gap relative to the spindle.

Due to the complexity and cost of these measuring devices, they cannot completely meet the requirements of industrial process users and test laboratory users. Also, conventional designs are not designed to be compatible with the various tests that users require, which makes it unacceptable to purchase many devices or to purchase expensive devices that are impractical. It is unavoidable or the test function is limited.

[0005]

SUMMARY OF THE INVENTION One object of the present invention is to overcome the above-mentioned drawbacks of the prior art.

This object is realized by the measuring device according to the invention comprising a spring chamber or other (eg conical plate) subassembly and associated electromagnetic transducers, flexural torsion springs, and stone and pin bearing mechanisms. To be done.

[0007]

In one embodiment, the lower assembly is raised along a guide rail to replace a spindle chamber lower assembly in the central region,
Also, the lower lower assembly can be released and lowered to lock to the central lower assembly. The mechanism as a whole ensures reliable radial and axial positioning after such replacement.

Other objects, features and advantages of the present invention include:
The following detailed description of the preferred embodiments, together with the accompanying drawings, will become apparent.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of the present invention shown in FIGS. 1-3B has an annular region therebetween (typically 0.0203 mm (0.003 mm)).
8 inch)) and a lower lower assembly 11 including a spindle 14 and a spindle 14 and a measuring device 10 is provided. The chamber 12 is suspended from the cylinder 16 via a removable joint 18 that includes a spring 18A and a retaining detent 18B.

The cylinder 16 includes a motor 24 and a gear 25.
Is attached to the fixed structure 20 via bearings 22-1 and 22-2 which are rotatably (with the chamber 12) separated by the driving force of. The sensing shaft 26 is the hole 2 of the fixed structure.
The lower portion 27 extends through 0A and can be secured to the shaft extension 14A of the spindle 14 via a removable joint 28. The pin and stone attachment mechanism 26A is
Shaft extension 14A (and with it spindle 1
4) and the shaft 26 are precisely aligned.

The transducer 30 records the rotational movement of the shaft 26, which is driven by the motor 24 driving the chamber 12 and transmitting the driving movement to the spindle 14 through the sample fluid, such as fluid viscosity, temperature and other factors. Of the calibration factor of The converter includes a stator 32 attached to the fixed structure 20 and a rotor 34 fixed to the shaft 26. Yet another shaft 26 attachment is via a flex pivot pin element 36C, which comprises a flex pivot pin 36 with a cap 36A attached to the fixed structure 20, to surround the shaft 26 with the surrounding sleeve 3.
Support 6. The wiring (not shown) from the converter 30 is
The outside of the fixed structure 20 can be reached through the hole 20H. 1 to 3B, the conventional guards, chassis components and other fixed structures are omitted.

By loosening the bolts on fitting 28 (via port 18) and disconnecting chamber 12 (spring 18A).
To rotate the connector 18 to cover the chamber 12 with the cover 12A, the spindle 14 and its shaft extension 1
A continuous sample can be obtained (by dropping with 4A). Alternatively to this, the chamber 12 is first lowered after the connector 18 is loosened, and then the fitting 28.
You can also loosen. In either case, the chamber 12
By replacing the fluid sample therein and reversing the disassembly procedure, the components 12, 14 can be reassembled into the measuring device 10.

Part 1 of the entire iterative disassembly / assembly procedure.
The interval of 2 and 14 can be accurately secured again by the following features.

That is, the spaced bearing elements 22-1, 22-
2 and the presence of long concentric features 16, 20, 26 in between.

Presence of pin-stone attachment mechanism 26A, flexure pivot pin 36.

[0016] Substantially no loosening (ie, no loss of precision) joints 18, 28 are provided based on the above mechanism.

By maintaining this precise control,
In contrast to the relative reading limitations of many conventional viscometers, it is possible to convert an absolute measurement of shear stress to an absolute viscosity measurement via a linear factor in the measuring instrument or software. Become.

FIG. 1A shows a variation of the conical (14 ')-plate (12') of the spindle chamber of FIG. 1 which can be mounted and operated as in FIG. Ancillary transducer 13A (ancillary means of primary transducer 30 of FIG. 1) senses the force applied to the plate and reads it through controller 13 for calibration purposes. Other variations will be apparent to those skilled in the art, for example parallel plate devices are also available. In all embodiments, the drive-driven relationship can be reversed.

FIG. 1B shows another modification applicable to FIGS. 1 and 1A, and another embodiment in which the flexible mounting portion is modified. The flexure mounting assembly 36 'in this variation includes a cap 36'A that supports the shaft 26.
And a sleeve 36'B (these caps 3
Both 6'A and sleeve 36'B have been modified from the equivalent parts 36A, 36'B of FIG. 1). The flex pivot pin element 36 is the same as in FIG. 1 (see also FIGS. 1 and 4A below).

A modified cap 36'A includes a thin diaphragm portion 36D that can be displaced axially (ie, axially of shaft 26) by rotating actuation screw element 36E. After such displacement, the adjusted axial position is locked via the bolt 36F.

Auxiliary converter 13B and controller 13
C provides a measure of axial force and / or displacement acting on the diaphragm and assists in axial position calibration. The converter 13B can be an optical type, a capacitive type, an electromechanical type, or a magnetic type, but is preferably a capacitive type.

The sleeve 36'B is sized to accommodate different screw rotation versus axis motion devices 36E within the same measurement device geometry as shown in FIG. The device 36E can be rotated only once or twice, but due to the difference in pitch between the components (typically 2
8 to 27), the axial position can be responsively controlled without the need for artificial means such as precision grinding, small gear teeth or other microstructures.

The preferred embodiment of the invention shown in FIGS. 4-8 comprises a measuring device 40 having a central lower assembly 41 which comprises a sample chamber 42 with an annular region therebetween. (Typically 0.0203 mm (0.008 inch))
And a spindle 44 that accurately forms the gap, and the gap can be formed by precisely setting the dimensions and the rigidity of these components and related mounting components. The chamber is mounted on a shaft 46 and has spaced bearings 46.
A and 46B support the shaft in the housing 46C,
Detachable cap 46D, lip seal 46E and O
It has a ring 46F. The shaft is connected to a motor 50 via a fitting 48 which is housed within the housing 19 and comprises a rigid leg or panel assembly 19A and a top portion 19B carrying a rail 22. .

Rail 52 mounted on support 49
Supports the sides and alignably guides them via a connecting arm 54 which is adjustable via a precision clamping screw 54A and other means described below, from the rails of housing 46C. Of the sample chamber 42 relative to the similarly aligned spindle 44. Upper arm 5
6 (While positioning, allow up / down sliding,
Or, the adjusting screw 56 that locks to prevent such movement
(Comprising A) extends from the rail 52 and
Attach 0. Together, flexure pivot pin 57 and stone bearing 59 mount shaft 55 as described with respect to FIGS. 1 and 1B.

The upper assembly 60 includes a sensing shaft 58, a flexure bearing, a transducer 61, an upper shaft 55, and associated support.

The basic procedure of a series of measurements (as shown in FIG. 8) is as follows. That is, the upper lower assembly 60 is lifted to separate the parts 42, 44, 46, 48, 52 from the upper and lower lower assemblies via the quick disconnect fitting 48, and the cap 46D of the part 46 is replaced for fluid exchange. It is lifted from the housing 46C, removed, and then inserted again.

The measuring device described above has the following structural and operational features.

(1) It is desirable that the chamber 42 (not the spindle 44) be driven by the motor 20. This is a stable and common means of minimizing the eddy currents and turbulence that normally occur during spindle drive. But,
Depending on the application example, it is also possible to adopt a spindle drive method.

(2) The rotary flex pivot pin 57 joined to the pin and stone support means 59 has minimal friction, while the sensing shaft 58 (in the stator coil of the converter (rotary variable differential transformer) And the rotating element of the transducer 61) on it and the coaxial alignment of the spindle and the chamber. This configuration exerts a radial resistance force but no circumferential or axial friction force.

(3) For the upper and lower parts, easy-to-operate and precise mounting devices can be applied.

The cylinder 42 is a stepping motor 50.
(Or other good speed control motor) it is desirable to drive from zero to high speed rpm (several thousands of revolutions). The motor provides precise speed control (typically 25,000 steps per revolution in this case) and is controlled (in combination with the known geometry of the chamber and spindle or similar components). Provides a high shear rate.

The measured values of the transducer can be converted into shear stress.

In this case, what is of interest is a flexure provided with and connected to a spindle-like component, which comprises a linear / rotary flexure pivot pin and a motor / belt drive-driven outer cylinder. Applicant's earlier U.S. Pat. No. 4,175,425 issued Nov. 2, 1979, relating to a viscometer with a pivot pin. The use of flexural pivot pins is described in US patents such as Merrill,
Figure 3 shows a chamber supported by a rotary flexure, which is axial, radial and rotatably supported and is the only means of supporting the chamber.

As shown in FIG. 5, a partition 47 divides the annular space between the chamber 42 and the housing 46 into concentric passages, two concentric passages being fed into the inlet port (1). While cooling the water, suck the water at the outlet port (O). When the chamber 42 is removed from the color sheet 47A or the shaft 46, the cooling water simply remains at the bottom of the hub formed in the partition 47. The ring 47B on the collar slidably engages an annular groove 47C in the bottom of the chamber 42,
Providing positioning means.

FIGS. 6 and 7 show upper and lower joints 32 and 18, respectively, which are generally annular clamps that can be loosened or tightened via a single screw.

The present invention provides a significant improvement in alignment over the constructions of the above-referenced US Pat. No. 4,175,425 and Merrill patents. The present invention also relates to the above-mentioned US Pat. No. 4,175,425.
It facilitates replacement of flexure pivot pins for range adjustment, as compared to the No. and Merrill patents. In addition, the present invention allows the important feature of using sensitive flexure means to measure thin fluids at low shear rates, which is not feasible with the structure of U.S. Pat. It is possible. This is because with the rigidity and construction of the sealed tube of the Merriller patent, it is not possible to achieve the above features because the flexing means must support the chamber without the use of assisting means. The present invention also provides an effective fluid retention function that complies with the above.

It will be apparent to those skilled in the art that other embodiments, modifications and variations are possible in accordance with the spirit of the above disclosure and the scope of the present invention. The scope of the invention should be determined solely by the appended claims in accordance with patent law, including the theory of equivalents.

[Brief description of drawings]

FIG. 1 is a front view of a rheology measuring device according to a preferred embodiment of the present invention. FIG. 1A is a partial schematic view of a selectable conical-plate embodiment. FIG. 1B is a partial front view of a heating attachment portion of the rheology measuring device of FIG. 1 or 1A according to a preferred modification.

2 is a front view of a fixed structure element of the rheology measuring device of FIG. 1; FIG. 2A is a plan view of components of the measuring device. FIG. 2B is a bottom view of the components of the measuring device.

FIG. 3 is a side view of the shaft component of the embodiment of FIG. 3A is a bottom view of the shaft component of the embodiment of FIG. 3B is a partial cross-sectional front view of the shaft of the component of FIG.

FIG. 4 is a partial side view of a rheology measurement device in a closed position and an open position according to yet another embodiment of the present invention.
FIG. 4A is a plan view of a portion of the deflectable generally frictionless pivoting element of the embodiment of FIGS. 7-11.

FIG. 5 is a partial enlarged cross-sectional view showing a working element.

FIG. 6 is an enlarged view of a joint element.

FIG. 7 is an enlarged view of a joint element.

FIG. 8 is a partial side view of a rheology measurement device in a closed position and an open position according to yet another embodiment of the present invention.

[Explanation of symbols]

10 Rheology Measuring Device 11 Lower Lower Assembly 12 Chamber 12A Cover 13 Converter 13A Auxiliary Converter 13B Auxiliary Converter 13C Controller 14 Spindle 14A Spindle Shaft Extension 16 Cylinder 18 Joint 18A Spring 18B Holding Detent 20 Fixed Structure 20A Fixed structure hole 20H Fixed structure hole 24 Motor 25 Gear 26 Sensing shaft 26A Stone-pin attachment mechanism 27 Lower part 28 Joint 30 Transducer 32 Stator 34 Rotor 36 Flexible pivot pin 36A Cap 36B Sleeve 36C Deflection Pivot pin element 36D Diaphragm 36E Actuating screw element

Claims (12)

[Claims] 1. A rheology measuring device comprising: (a) means for forming a chamber-like surface of a specimen; and means for retaining a fluid adjacent to said surface so that the rheological properties of the fluid can be measured. ) Means for forming an inner spindle-like element facing the chamber-like element and mounted by the chamber-like element so as to form a precise void for fluids, the relative between the spindle and the chamber (C) rotating at least one of the chamber and the spindle at a selected precise speed as a driven element by applying a shearing force from one driving element to another element through the fluid in the air gap as a driven element. Precision drive means with selectable speeds to allow for: (d) means for forming a sensing shaft as an extension of the spindle shaft; (e) axially Elastic springs and attached long shafts, without axial and rotational friction, but rigidly supporting the shafts in a radial manner, resulting in a net deflection that correlates to the force imparted by the shear force of the fluid. A bearing mounted at the other end that absorbs torque of the driven shaft via the sensing shaft with a responsive spring action transmitted back to the sensing shaft for A rheology measuring apparatus comprising: means for forming a torsion spring mechanism; and (f) transducer means for producing an output signal in response to rotation and spring movement of the spindle element sensed by the sensing shaft. 2. A rheology measuring device according to claim 1, wherein the means (e) are provided near the top of the flexural rotary spring, an elongated longitudinal shaft supported by the spring, and near the bottom of the shaft. And a stone-pin rotation fixture, wherein the effective length between the flexure fixture and the stone-pin fixture ensures that the radial drive element-driven element clearance ensures measurement accuracy. And a removable joint between the lower end of the elongate shaft and the shaft extension of the spindle, the sensor rotor being mounted on the elongate shaft or at the elongate shaft. A rheology measuring device, characterized in that it is attached to one of the extension parts of the shaft and is brought into close proximity so as to change to a degree smaller than the gap between the driving element and the driven element. 3. The rheology measuring device according to claim 1, wherein one of the elements is a damper having a cover,
Rheology measuring device, characterized in that the other element is a spindle, the chamber, the spindle and the cover being removable via a quick disconnect joint of the respective shafts extending from these elements. 4. The rheology measuring apparatus of claim 3, further comprising quick disconnect means for accurately and adjustably mounting the upper and lower lower assemblies, wherein the upper and lower assemblies include the spring means and the transducer. Means, said lower lower assembly comprises a drive shaft of said motor means, said guide means positioning guide groove means and upper and lower lower assemblies relative to said guide groove means, said central groove Rheology, characterized in that it comprises separate precision spacing means for allowing the upper lower assembly to linearly separate and occlude for removal and insertion of the chamber-spindle lower assembly. measuring device. 5. The rheology measurement device of claim 1, wherein a substantially frictionless flexure mount engages the spindle. 6. The rheology measuring device according to claim 1, wherein the flexible attachment is a rotary type. 7. The rheology measuring device according to claim 1, wherein cooling means for the circulating fluid is arranged around the chamber which does not interfere with the removal of the chamber from its operating position and its insertion into the operating position. Rheology measuring device characterized by. 8. The rheology measuring device according to claim 1, wherein the device is conical and plate-type, further comprising means for adjusting the axial air gap between the driving element and the driven element. Rheology measuring device characterized by. 9. The rheology measuring device according to claim 8, wherein the adjustment of the axial air gap raises and lowers the spindle or chamber and a differential screw mechanism and a drive element and a cover, such as in a conical and plate mechanism. Rheology measuring device, comprising means for detecting a contact point with the driving element. 10. The rheology measuring device according to claim 9, wherein the detection of the contact point between the driving element and the driven element acts on the driven element at the contact point or at the tip of the contact point. A rheology measuring device having a structure and an arrangement that are performed by detecting an increase in the axial force. 11. Rheology measuring device according to claim 10, having a structure and arrangement such that the axial force (normal force) on the spindle and / or the chamber during operation can be measured by the transducer means. Rheology measuring device characterized by. 12. Rheology measuring device according to claim 11, characterized in that it is combined with said transducer means for measuring said force.