Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
  • G01N3/34—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces generated by mechanical means, e.g. hammer blows
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
  • G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
  • C03C8/16—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions with vehicle or suspending agents, e.g. slip
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
  • G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
  • G01N11/12—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material by measuring rising or falling speed of the body; by measuring penetration of wedged gauges
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N3/40—Investigating hardness or rebound hardness
  • G01N3/48—Investigating hardness or rebound hardness by performing impressions under impulsive load by indentors, e.g. falling ball

Definitions

• This invention relates to a new and improved rheometer for predicting the slump resistance of high solids suspensions such as TV sealing frit paste.
• the flow of most particle-filled suspensions is in a Non-Newtonian mode, wherein the viscosity is a function of the shear rate and/or the shear time.
• Such suspensions are predominately pseudoplastic, such that the viscosity decreases as the shear rate increases, and often they are thixotropic, wherein the viscosity decreases as the shear time increases.
• Pastes having a relatively high degree of solids suspended therein, and with an extremely high degree of pseudoplasticity exhibit a yield stress in the form of a false body which resists external stresses of a finite magnitude. Only when the external stresses exceed this critical value (the yield stress) does any strain become possible. Since most available rheometers can only measure paste response, that is torque, force, displacement, angular motion, etc. in a steady-state fashion, this false body of the paste under test is often disrupted or even destroyed while it is being tested.
• 1,232,782; 1,651,596; 1,748,512; 1,748,513; 5,144,832; and 5,327,778 all of which utilize a weight to force a plunger or ball downwardly into a test substrate, with the 1,748,512 and 1,748,513 patents also utilizing an oil bath and piston to control the downward movement of the weighted plunger or push rod.
• U.S. patents nos. 1,894,369; 2,625,034; and 2,747,399 all utilize the use of a balance or scale to measure the rates of penetration of a test sample.
• U.S. patent no. 2,638,779 measures the current to a magnetic coil to obtain a reading as to resistance to penetration of a sample.
• patent no. 5,357,786 utilizes an electromagnetic balance which provides a signal or reading relating to the vertical impingement of a plunger on a sample.
• none of the foregoing references suggests the utilization of a constant speed traveling stage to insert the ball into the test sample and measuring the maximum force on the ball as it travels through such sample. It thus has been an object of the invention to provide a new and improved falling ball rheometer wherein the ball is moved linearly at a constant predetermined speed into a test sample having a high concentration of solids suspended therein, and measuring the maximum force produced on the ball as it travels through the test sample.
• the present invention sets forth both method and apparatus for measuring the maximum force exerted on a plunger or ball as it travels at a constant speed through a portion of a test sample. More particularly, the method and apparatus of the present invention has utilization for predicting the slump resistance of a sample having a high concentration of solids suspended therein, such as TV frit pastes .
• a moving rod with a ball- shaped tip is provided upon a traveling stage which moves linearly at a desired constant speed into a pool of the paste to be tested, while a force gauge attached to the rod monitors and records the maximum force exerted thereon during its travel through a portion of the test sample.
• the linear or downward motion of the ball is controlled by a motorized DC mdexer connected to a miniature PCU and under the control of ICL (Intelli-Command-Language) software.
• Fig. 1 is a somewhat schematic side elevational view of an improved rheometer of the present invention.
• Fig. 2 is a front elevational view thereof.
• Fig. 3 is a top plan view thereof.
• an improved rheometer 10 of the present invention comprising an upright slide stand or test stand 12 having a base plate or sample retaining portion 14 and a linearly moveable slide member 16 mounted thereon.
• the upright test stand 12 has a supporting back plate 18 and a pair of slide guide rails 20, 22 secured to the backplate 18 and between an upper cover member 24 and a bottom member 26 which is secured to the sample retaining portion 14.
• the slide member 16 is provided with a ball screw arrangement 28 and complimentary rails so as to move linearly up and down along guide rails 20, 22.
• a stepper motor 30 is mounted on the test stand 12 and is operatively connected to the ball screw through connector housing 32 so as to drive the ball screw means and move the slide member 16 linearly along the slide guide rails 20, 22.
• a controller module 34 described in more detail hereinafter, controls the operation of stepper motor 30 and accordingly the movement of the slide member 16 along guide rails 20, 22 of upright stand 12.
• An adapter member 36 is connected to the slide member 16 and has a digital force gauge 38 secured to the outer end thereof.
• a ball tip 40 is attached to a rod 42, which is screwed into the force gauge 38.
• the force gauge has a digital read out face 44 for recording test measurements.
• upper and lower limit switches 46, 48 may be provided to limit the vertical extent of the slide 16 along the rails 20, 22 of the upright slide or test stand 12.
• the rheometer 10 incorporates the use of a moving rod
• a force gauge 38 having the rod 42 attached thereto, monitors and records the maximum force exerted on the ball during its downward movement withm the paste contained in container C.
• the downward motion of the ball 40 is produced by the downward movement of the slide member 16 through the ball screw means 28, which in turn is controlled by the stepper motor 30.
• motor 30 is connected to a miniature Central Processing Unit (CPU) under an Intelli-Command-Language (ICL) software, which is set forth hereinafter.
• CPU Central Processing Unit
• ICL Intelli-Command-Language
• the force gauge 38 located above the falling ball rod 42, is a digital force gauge capable of recording and displaying the maximum compression force exerted thereon through the ball tip 40, as the tip moves through the test sample withm container C.
• Such force gauge may be a model CI-FGE2 force gauge obtainable from Controls International of Chicago, Illinois.
• the CPU operates the linearly moveable slide 16, carrying the force gauge 38 and ball tip 40, as a constant speed traveling stage, to insert the ball mto the test sample or paste contained in container C.
• the CPU in the drive unit utilizes the ICL software to drive the DC stepper motor at a predetermined constant speed so as to move the ball tip 40 into a pool of paste or test sample at a constant speed.
• the force gauge 38 is programmed to capture the maximum force exerted thereon through the ball tip.
• the CPU controls the stepper motor in half steps so as to obtain a smooth flowing movement of the slide 16 along the stand 12 without any harmonic vibrations.
• the CPU may be programmed to move the ball rapidly downwardly to just above the sample, and then the constant predetermined speed is utilized to move the ball mto the sample and obtain a peak or maximum force reading on the force gauge as the ball moves withm the sample itself.
• the test stand may be a VersaTest model EP-59880-54 produced by Cole-Parmer Instrument
• the rheometer of the present mvention is m fact a relative measurement instrument, and therefore it is necessary that the diameter of the ball tip 40, and the diameter of the cup C retaining the test sample or paste, be kept constant in order to compare the stiffness or slump resistance of one paste to another.
• a test sample or paste is preferable shaken for three minutes on a standard shaker such as a Red Devil pail shaker.
• the sample is then positioned withm container C on the sample retaining portion 14 of the test stand 12.
• the test is started with the ball tip 40 positioned just above the paste surface, and not in contact therewith.
• the controller module is actuated to move the motorized stage (including the slide 16, adapter member 36, force gauge 38, ball 40 and rod 42), downwardly along slide rails 20, 22 of upright stand 12 at a controlled constant speed such as 0.02 inches per second.
• the ball tip 40 is preferable inserted into the sample such that the periphery thereof is between 1.5" and 2" from the edge of the container C.
• the depth of the ball tip drop is preferably terminated at 1" above the bottom of the container C. As the ball tip travels through the paste, the maximum force exerted thereon is recorded by the digital force gauge 38.
• test results obtained from the rheometer are utilized to predict the slump resistance of high solids suspensions, such as TV sealing frit paste. Meaningful test results are obtainable with the present mvention due to the fact that the ball tip is driven by a motorized stage or slide unit at a controlled predetermined constant speed, while the maximum force experienced by the ball tip is recorded by the digital force gauge.
• the CPU utilized to drive the stepper motor is provided with an ICL program that produces the desired results, and accordingly the following program has been found to provide those results.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
• Sampling And Sample Adjustment (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Cited By (6)

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Citations (15)

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• 1997
  • 1997-04-07 CN CN97193896A patent/CN1216610A/zh active Pending
  • 1997-04-07 WO PCT/US1997/006263 patent/WO1997039332A1/en not_active Application Discontinuation
  • 1997-04-07 EP EP97920406A patent/EP0894258A4/en not_active Withdrawn
  • 1997-04-07 JP JP9537316A patent/JP2000508772A/ja active Pending
  • 1997-04-07 KR KR1019980708324A patent/KR20000005528A/ko not_active Application Discontinuation
  • 1997-04-14 TW TW086105088A patent/TW344794B/zh active

Patent Citations (15)

Non-Patent Citations (1)

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