Brookfield Dial Viscometer Bedienungsanleitung PDF herunterladen (Seite 14)

Brookfield Engineering Laboratories, Inc. Page 14 Manual No. M/85-150-P700

4) Attach sample cup to viscometer and allow approximately 15 minutes for temperature equilib-

rium.

5) Measure the fluid's viscosity and record the viscometer readings (both % torque and cP).

6) See "Interpretation of Test Results" shown below for calculation of total calibration tolerance

(instrument and fluid).

Notes: 1) The spindle must rotate at least (5) times before a viscosity reading is taken.

2) The use of Brookfield Viscosity Standard fluids in the range of 5 cP to 5000 cP is

recommended for cone/plate instruments. Please contact Brookfield Engineering

Laboratories or an authorized dealer if your calibration procedure requires more

viscous standards.

3) Select a viscosity standard fluid that will give viscosity readings between 10% and

100% of full scale range. Refer to Appendix B for viscosity ranges of cone spindles.

Do not use a silicone viscosity standard fluid with a viscosity value greater than 5000

cP with a Cone/Plate Viscometer. Brookfield offers a complete range of mineral oil

viscosity standards suitable for use with Cone/Plate Viscometers as shown in Table

D2 (Appendix D). Consult with Brookfield or an authorized dealer to determine

which fluid is appropriate.

Mathematics of Cone/Plate Geometry

Cone and Plate geometry, as illustrated in Figure A9, is the fixation of a conical vertex perpen-

dicular to and in point contact with a flat plate. When the cone is made very obtuse (θ less than

4°) and rotated at constant speed (ω), precise viscosity measurements are obtained at absolute

and uniform values of shearing rate and stress.

Viscosity (in poise) is the ratio of shear stress to shear rate. Shear stress is related to the summa-

tion of torque ( T ) over the conical surface. Shear rate is related to the cone rotational speed

(ω), and gap width (c) at any radial distance (r) from the center of the rotating cone.

Figure A9

Cone

Plate

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Brookfield Dial Viscometer Bedienungsanleitung Seite 14