BYK CAP 1000+, Руководство пользователя, Страница: 26 / 32

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Appendix B
APPENDIX B - CALIBRATION PROCEDURES
Normally there is no requirement to perform a cone calibration. Cones supplied at
the time of order are calibrated to the viscometer prior to shipment.
VERIFICATION OF CALIBRATION
At selected intervals, depending upon usage and number of operators, the CAP
Viscometer calibration should be verified using NIST Fluids. Referring to Appendix A
(Table A-1), find the appropriate NIST Fluid(s) for the cone(s) being used.
With the viscometer set up, perform viscosity measurements following the outline
of Section III. Prior to pressing the RUN key to initiate a cone calibration, we
recommend a period of thermal equilibrium of approximately 30 minutes for the fluid,
cone and plate. This period should begin immediately after entering the calibration
temperature and associated viscosity value (in cP). Execute viscosity measurement
and record results.
Verify the result to have an accuracy according to the information in Section III (Table
III-1). If the calibration is outside the accuracy limits, proceed with the following
Cone Calibration.
INTERPRETATION OF CALIBRATION TEST RESULTS:
When verifying the calibration of the CAP 1000+, the instrument and viscosity
standard fluid error must be combined to calculate the total allowable error.
The CAP 1000+ accuracy is defined in Section III.1 as a function of spindle number 03.
BYK-Gardner Viscosity Standards Fluids are accurate to (+/-) 1% of their stated value.
EXAMPLE: Calculate the acceptable range of viscosity using CAP 1000+ with
Spindle 03 at 900 RPM; Standard Fluid CAP-3L with a viscosity of
350 cP at 25°C:
1) Calculate full scale viscosity range using the equation:
Full Scale Viscosity Range [P] =
Range Coefficient
RPM
Where: Range Coefficient = 7500 from Table A2
Full Scale Viscosity Range 7500
= 8.33 P (833 cP)
900
The viscometer is accurate to (+/-) 16.7 cP. (which is 2% of 833)
2) The viscosity standard fluid is 350 cP. Its accuracy is (+/-)1% of 350 or (+/-)3.5 cP .
3) Total allowable error is (16.7 + 3.5) cP. = (+/-) 20.2 cP. (0.2 P. ).
4) Therefore, any viscosity reading between 329.8 and 370.2 cP. indicates that the
viscometer is operating correctly. Any reading outside these limits may indicate
a viscometer problem. If the reading falls outside the acceptable range, perform
a cone calibration ( Appendix B ). If the calibration is outside the accuracy limits,
proceed with the following Cone Calibration.