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CALIBRATION PROCEDURE USING HELIPATH STAND AND T-BAR SPINDLES
When a Helipath Stand and T-Bar spindles are used:
•
Remove the T-bar spindle and select a standard LV (#1-3) or RV, HA, HB (#1-6) spindle. Follow the
procedures for LV (#1-3) and RV, HA, HB (#1-6) AMETEK Brookfield spindles outlined above.
•
T-Bar spindles should not be used for verifying calibration of the DVPlus Viscometer.
CALIBRATION PROCEDURE FOR SPIRAL ADAPTER
AMETEK Brookfield recommends a two-step check. First, verify the calibration of the Viscometer using the standard
Viscometer spindles (LV #1-3, RV #2-6, HA #2-6 and HB #2-6) as detailed in this Appendix. Second, verify the
calibration of the Viscometer using the Spiral Adapter. The use of an accessory device may increase the accuracy of
measurement associated with the DVPlus.
•
Place the viscosity standard fluid (in the proper container) into the water bath (refer to the Spiral Adapter
instruction manual).
•
Attach the spindle to the Viscometer. Attach chamber (SA-1Y) and clamp to the Viscometer.
•
Lower the DVPlus into measurement position. Operate the Viscometer at 50 or 60 RPM until the chamber
is fully flooded.
•
The viscosity standard fluid, together with the spindle, should be immersed in the bath for a minimum of 1
hour, stirring the fluid periodically (operate at 50 or 60 RPM periodically), prior to taking measurements.
•
After 1 hour, check the temperature of the viscosity standard fluid with an accurate thermometer.
•
If the fluid is at test temperature (+/- 0.1°C of the specified temperature, normally 25°C), measure the
viscosity and record the Viscometer reading. Note: The spindle must rotate at least five (5) times or for
one minute, whichever is greater before readings are taken.
•
The viscosity reading should equal the cP value on the viscosity fluid standard to within the combined
accuracies of the Viscometer and the standard (as discussed in the section entitled, Interpretation of
Calibration Test Results). However, instrument accuracy is ±2% of the maximum viscosity range and not
the standard 1%.
Viscometers as shown in Table E-2. Consult with AMETEK Brookfield or an authorized dealer to determine which
fluid is appropriate.
INTERPRETATION OF CALIBRATION TEST RESULTS
When verifying the calibration of the DVPlus, the instrument and viscosity standard fluid error must be combined to
calculate the total allowable error.
The DVPlus is accurate to (+/-) 1% of the range in use when using spindles LV #1-3, RV #2- 6, HA #2-6 and HB
#2-6. When using an accessory device with the DVPlus such as Small Sample Adapter, UL Adapter, Thermosel, Spiral
Adapter, and DIN Adapter the accuracy value may be increased. In general the increase in accuracy will be minimal,
however, it could be as much as 1% for a total accuracy of +/- 2% of the range in use.
AMETEK Brookfield Viscosity Standards Fluids are accurate to (+/-) 1% of their stated value.
Example:
Calculate the acceptable range of viscosity using DVPlus RV with RV-3
Brookfield Standard Fluid 12,500 with a viscosity of 12,257 cP at 25°C:
1) Calculate full scale viscosity range using the equation:
Full scale Viscosity Range
M21-400 REV.1.1
D V P L U S D I G I TA L V I S C O M E T E R - O P E R AT I O N A L M A N U A L
Spindle at 2 RPM; AMETEK
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