Aem Lect14


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Aem Lect14

  1. 1. Viscosity:Newton’s law y A F F dv =η A dy v=0 Velocity gradient x z Advanced Electronic Ceramics I (2004) Cylinder-type Viscometer The ViscoTester 550 is a rotational viscometer for sophisticated and automized quality control giving absolute viscosity data at defined shear rates and accurate temperature control. It is suitable for the complete characterization of Newtonian and non- Newtonian fluids including the measurement of yield points or thixotropy. Specifications: Viscosity range (mPas) 1 - 1 000 000 Torque range (mNm) 0.1 - 30 Speed range (rpm) 0.5 - 800 Temperature range (°C) -20 - 100 Sample volume (cm3) 8 - 80 Typical testing time (min) 1 Reproducibility (+/- %) 1 Comparability (+/- %) 2-4 Remarks absolute viscometer Advanced Electronic Ceramics I (2004)
  2. 2. Cone and Plate Viscometer Advanced Electronic Ceramics I (2004) Cone and Plate Viscometer - highly viscous liquid and paste - butter - Binding agent, resins, ink, paste solder - resistance paste Cone rotate thus shearing the test sample The torque of the rotating cone depends on the viscosity of the fluid. - measurement at the different angular velocities enables the viscosity measurement as a function of shear rate Advanced Electronic Ceramics I (2004)
  3. 3. Rotational-Type Viscometer The ViscoTester 7 instrument is a classic rotational viscometer for the fast determination of viscosity as defined in ISO 2555 and many ASTM standards. The results are 100% compatible to the Brookfield method. It features an RS232 interface for data transfer to PC or printer, digital display with viscosity readout, windows software (optional) for data display and evaluation, a complete set with spindles, stand and carrying case and a 24 month full warranty with optional extension via service contract. Specifications: measurement Speed steps (rpm) 0.3, 0.5, 0.6, 1, 1.5, 2, 2.5, 3, 4, 5, employs a spindle 6, 10, 12, 20, 30, 50, 60, 100, 200 immersed in the Number of spindles L 1-4, R 2-6 Temperature range (°C) up to 150 fluid sample to Sample volume (cm3) 650 sense torque Typical test time (min) 1 to 2 resistance when Mains 115-230/50-60Hz running at Repeatability (+/- %) 0.5 constant speed. Advanced Electronic Ceramics I (2004) Portable Viscometer Advanced Electronic Ceramics I (2004)
  4. 4. Falling Ball Viscometery A fluid sample - in almost all cases it is liquid - is contained in a glass measuring tube (1) surrounded by a jacket (3) to allow an accurate temperature control by means of a constant temperature circulator. This tube is positioned in a 10° inclination with respect to the vertical. The tube has two ring marks A and B spaced apart by DL = 100 mm. A ball (2) is allowed to fall through the fluid sample. Falling from the starting position (speed v = 0) at the top of the tube the ball first accelerates along the distance Lv to allow the ball to reach a steady-state speed providing a uniform shear flow of the liquid in the sickle-shape gap surrounding the ball. The time Dt required for the ball to pass between the two ring marks A and B is measured. The value Dt can be used to calculate viscosity in the absolute units of [mPa·s]. The instrument is calibrated by means of Newtonian liquids of known viscosity. Advanced Electronic Ceramics I (2004)