Appendix B - Gap Setting Procedure For The Rst-Cps Rheometer - Ametek BROOKFIELD RST Operating Instructions Manual

Appendix B - Gap Setting Procedure for the RST-CPS Rheometer

This procedure is for the RST-CPS Rheometer. Procedures for both the manual gap and automatic gap
models are included. If there is a black micrometer ring on the RST-CPS Rheometer, it is a manual gap
setting instrument. Otherwise it is an instrument with automatic gap control.
"The gap" refers to the gap between a cone or plate spindle and the measuring bottom plate. For cone
spindles, the gap height is the height of the tip of the cone, which has been truncated so as to prevent
contact between the cone spindle and the measuring bottom plate. This value is indicated on the cone
spindle data sheet as the cone truncation value. The gap height for plate spindles is usually determined
by the largest particle size in the material. Best practice is to use a gap height 5 to 10 times greater
than the largest particle diameter. (For example, if the largest particle in the substance is 0.010 mm,
then the gap height should be 0.050 to 0.10 mm.) If the material does not have large particles, but is
highly viscous, experiment with various gap heights to determine what will give the most repeatable
viscosity measurements.
Any time a spindle is changed, the gap needs to be adjusted. If a user is running multiple back-to-back
tests with the same spindle, only removing the spindle between tests to clean it, then the gap only needs
to be adjusted before the first test, and the gap setting procedure can be skipped for the proceeding tests.
Before any test is performed, in standalone mode or under PC control, the touch screen display system
will present the user with the prompt shown in Figure B-1. To begin the gap setting procedure, choose
Yes.
B.1 Procedure for Manual Gap Adjustment Instruments
1) Ensure that the spindle and measuring bottom plate are clean. There should be no sample
material on the plate. The rheometer head should be in the raised position.
2) Loosen the hexagon screw on the shaft of the spindle, as instructed by the display screen
shown in Figure B-2. Pull down on the cone spindle to make sure that the shaft is fully
extended. When finished, press OK.
AMETEK Brookfield
Figure B-1
Figure B-2
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