The Brookfield KU-1+ Viscometer measures fluid viscosity in Krebs units. The digital display of
the Viscometer shows viscosity in Krebs Units (KU) or in the associated grams value (gm). A
paddle type spindle is driven at 200 rpm by a constant speed motor. The reaction torque of the
spindle rotating at 200 rpm is converted to viscosity in Krebs Units. The Viscometer will measure
viscosity from 40 KU to 141 KU, at weights from 32 to 1,099 grams. Application reference
information can be found in ASTM-D562.
I.1Components
The KU-1+ Viscometer package (Figure 1 and Figure 1.1) includes:
(1) KU-1+ Viscometer, upright rod and base(1) U.S. pint can (KU1-34) - not shown
(1) Paddle spindle (KU1-10)(1) Power Cord, 115 VAC (DVP-65) or
(1) US 1/2 pint can adapter (KU1-73)220 VAC (DVP-66)
(1) US pint can adapter (KU1-74)(1) Operating instructions (M/97-241)
POWER
KU-1+
VISCOMETER
KREBS UNITS
HOLD
gm
KU1-73
KU1-74
KU1-10
Figure 1 (front view)Figure 1.1 (side view)
Please check to be sure that you have received all components, and that there is no damage. If you
are missing any parts, please notify Brookfield or your local Brookfield agent immediately. Any
shipping damage must be reported to the carrier.
The air purge option (Brookfield Part No.
KU-1A) allows the interior of the KU-1+ to
be pressurized with air (or an inert gas) when
the instrument is to be used in a hazardous
environment (Figure 2). A built-in pressure
switch turns the instrument off when the
pressure drops below 2.0 PSI (falling). The
switch comes on at 10.0 PSI (rising).
Connect a regulated clean air supply which
is non-corrosive to brass to the fitting shown
in Figure 2. Adjust the pressure to approximately 25 PSI.
Note: The pressure switch range is 0-40 PSI.
DO NOT CONNECT PRESSURE HIGHER
THAN 40 PSI TO THE SWITCH!
Air Purge Fitting
I.2.2 Optional Paste Spindle
The paste spindle, Part No. KU1-75Y, (Figure 3) is a special spindle;
it is not included in a normal shipment/order. The design consists of
offset rod-type vanes, approximately 2 mm diameter x 19 mm long.
This spindle is suitable for use with high consistency materials such as
roller mill pastes. Do not use this spindle to report normal Krebs Unitmeasurements. Record the grams value shown in the digital display
and note that the paste spindle was used to make the viscosity
measurement.
I.3Viscometer Specifications
Range:40–141 KU
32–1,099 gm
Accuracy:± 1% of full scale range
Repeatability:± 0.5% of full scale range
Paddle speed:200 rpm ± 0.1 rpm
Printer output:25D-Type Centronics Parallel Printer Output
Net weight:22 lb. (10 kg)
Gross weight:25 lb. (11 kg)
Dimensions:15 x 11 x 20
Ambient conditions:-20°C (-4°F) to 65°C (149°F)
U.S. Pint3.850" (9.78 cm)3.385" (8.60 cm)
U.S. Half Pint2.850" (7.24 cm)2.875" (7.30 cm)
U.S. Quart4.845" (12.31 cm)4.230" (10.74 cm)
If you have a requirement for container dimensions other than those listed above, please contact
Brookfield or an authorized Brookfield agent.
I.5Utilities
Input voltage:115 VAC or 230 VAC
Input frequency:50/60 Hz
Power consumption:20 watts
Power cord color code:
USAOutside USA
Hot (live)BlackBrown
NeutralWhiteBlue
Ground (earth)GreenGreen/Yellow
I.6Printer Connection
The KU-1+ is equipped with a parallel printer
port located on the side of the instrument allowing printing with a parallel printer. A standard
parallel printer cable (25 pin, Type D Centronics,
available from Brookfield as part number CAP-
86) is used to connect the viscometer to the
printer.
When connected to a printer, the KU-1+ will
print one line of data each time the "Hold Reading" switch is moved to the down position.
The data line includes the viscosity (in Krebs
Units) and the associated weight (in grams):
715g125.9KU
Dashes in the printout indicate an "over-range"
condition or that the handle has risen to the top position (i.e. the spindle is not rotating):
- - - - g- - - . - KU
Note:When connecting the cable to the KU-1+, THE PRINTER POWER (AC mains) SHOULD
1) Be sure that the power switch is off. Attach the power cord to the appropriate power source.
2) Move the operating handle to the top (upper most) position.
3) Connect the printer (if used) to the parallel port. Be sure the printer power is off.
4) Loosen the thumb screw on the Viscometer shaft; insert the paddle spindle into the Viscometer
shaft, as far as it will go. Line up the groove on the spindle with the hole that the thumb screw
goes into. Tighten the thumb screw.
5) For Quart Cans: The can will be placed directly on the viscometer base.
6) For Pint Cans: Place the pint can adapter (KU1-74) on the viscometer base, pulling the spring
loaded front locator out and placing the adapter against the rear locating pins. Release the
locator to secure the adapter in place.
7) For 1/2 Pint Cans: Follow the procedure for pint cans. Place the 1/2 pint
can adapter (KU1-73) on top of the pint can adapter (KU1-74).
POWER
II.2Taking Measurements
1) Pour sample into the container. Fill to 3/4 inch (20 mm) of the container
lip.
2) Bring the sample in the container to the specified temperature.
3) Switch on the KU-1+ power switch and then the printer (if used). Switch
the Hold Reading Switch to the up position. (See
Figure 5.)
4) Select the desired display (KU or gm) using the
Display unit Selector switch.
5) For Quart Cans: Place the sample container on
the Viscometer base by pulling the spring loaded
front locator out, placing the container against the
rear of the locating pins, and releasing the locator
to secure the can in place.
6) For Pint & 1/2 Pint Cans: Place the sample
container directly on the can adapter mounted on
the viscometer base.
KU-1+
VISCOMETER
KREBS UNITS
HOLD
Figure 5
gm
7) Move the Viscometer handle down to the lowest
position. This will automatically immerse the
spindle into the fluid. If the correct amount of fluid
has been put into the container, the surface of the fluid will be at the immersion mark of
the spindle.
CAUTION: When using the 1/2 pint can, do not lower the spindle directly into the
container. The narrow diameter of the can requires the spindle to be introduced at an angle. Tilt the 1/2 pint can while lowering the viscometer.
8) The spindle will begin to rotate once the handle is within
1/2 inch of the lowest position.
9) Wait 5 seconds for the display reading to stabilize. A
display of "----" indicates an over-range condition. If a
printer is being used, these dashes will print in place of KU
and gm data (Figure 7).
10) Move the Hold Reading Switch to the down position to "Hold" the display. If a printer is
connected, a string of data will print as soon as the Hold reading switch is moved to the
down position (Figure 7).
11) Raise the handle to the top position. This stops the spindle from rotating.
123g 66.1KU
----g ---.-KU
Figure 7
Note: When using 1/2 pint cans, you must lift the can and then tilt slightly to remove the
spindle.
12) Loosen the thumb screw and remove spindle for cleaning.
Note: Do not remove the thumb screw. If dropped, it may fall into the sample.
II.3Troubleshooting
If the operating handle is in the DOWN position and the display locks up and/or the spindle
does not rotate the following should be checked:
• Be sure the HOLD switch is in the UP position. If the hold switch was in the DOWN
position prior to engaging the operating handle, dashes (——) or the previous reading may
appear in the display.
• The KU-1+ requires a shutdown (power off) period of at least 15 seconds before it can be
operated properly. If the unit had previously been turned off and immediately turned back on
(without a 30 second shutdown period) both the display and rotation may temporarily lock
up.
If you experience these problems, simply raise the operating handle, turn the unit off and wait a
minimum of 30 seconds before turning the power back on.
The accuracy of the KU-1+ is verified using viscosity standard fluids which are available from
Brookfield Engineering Laboratories or your local Brookfield dealer/distributor/representative.
Viscosity Standards are calibrated at 25°C. Available standards are listed in Table A1 below:
We recommend that Brookfield Viscosity Standard Fluids be replaced on an annual basis, one year
from the date of initial use. These fluids can be stored under normal laboratory conditions. Disposal
should be in accordance with local, state and federal regulations. Material Safety Data Sheets are
available upon request.
Calibration Check Procedure
The frequency of the calibration check should be based on your company's standard practice for test
and calibration of instruments.
1)Select any two viscosity standards listed in Table A1 to perform your calibration check. The
viscosity standards are very temperature sensitive. The viscosity value of the fluid will
change with temperature so it is important to control the temperature to 25.0°C.
2)Pour the selected fluid into a standard US 1-pint can. The spindle and the fluid in the can
should come to temperature equilibrium before proceeding with the calibration check.
It is important that the fluid and the spindle come to 25.0°C, ± 0.1°C, before proceeding
with the calibration check.
3)Once the fluid and spindle have come to thermal equilibrium, place the sample container on
the viscometer base, using the KU1-74 adapter. Switch the power switch and printer (if
used) to "ON". Switch the Hold Reading Switch to the "UP" position. Turn the Select knob
to "KU".
4)Move the viscometer handle down to the lowest position. The spindle will begin rotating
once the handle is within 1/2 inch of the lowest position.
5)Wait five (5) seconds for the reading to stabilize. Switch the Hold Reading Switch to the
"DOWN" position. You will need to record measurements in KU and grams. These two
values work together to let you interpret the calibration results.
6)After you have recorded results in KU, then move the Selector knob to the "gm" position and
record your reading in grams. If you are using a printer, both measurements will be sent to
the printer and will print out as soon as the Hold Display switch is switched back to the
DOWN position.
Interpretation of Calibration Check Results
When verifying the calibration of the KU-1+, the instrument tolerance and viscosity standard fluid
tolerance must be combined to calculate the total allowable error.
The KU-1+ is accurate to ± 11 grams, which is 1% of the full scale range in grams. The Brookfield
Viscosity Standard is accurate to ± 1% of the stated viscosity in KU.
The total allowable error should be stated in KU. Since the instrument accuracy is stated in grams,
you will have to use the comparison table (Table A2) and convert from grams to KU.
Correct interpretation of your calibration results requires that you compare your readings in grams to
the equivalent in KU. You must then bracket your reading with upper and lower limits based on the
allowable error of ± 11.0 grams. Convert this acceptable range in grams (as defined by the upper
and lower limits) to KU units.
Example: Calculate the allowable error of the KU-1+ using fluid KU106; the stated
viscosity of the fluid is 104.8 KU. The viscometer indicated a measured viscosity
of 105 KU and 410 grams.
1)Measured results from the calibration check in grams were 410 grams. Locate 410 grams on
the conversion chart (Table A2).
2)The KU-1+ is accurate to ± 11.0 grams. Starting from 410 grams, count 11 places above and
below the 410 grams. This is called "bracketing" the acceptable range. In this case, the
acceptable range will be from 399 grams to 421 grams.
3)Convert the acceptable range in grams to KU. Locate the minimum and maximum grams
bracketed. Look to the right of each number for the conversion to KU. In this case, it will be
103.9 KU minimum and 105.7 KU maximum. The total difference between 103.9 and 105.7
KU is 1.8 KU. Therefore, the accuracy is ± 0.9 KU. This is the accuracy for the
Viscometer in KU, ± 0.9 KU.
4)Now that you have the accuracy for the instrument, you can add it to the accuracy of the
fluid. The fluid is accurate to ± 1% of the stated value in KU. The viscosity standard is
calibrated at 104.8 KU, ± 1% is equal to ± 1.0 KU.
5)Total allowable error for the calibration check in this example is 104.8 KU, ± 1.9 KU (102.9
KU to 106.7 KU). Since the measured reading of 105 KU falls within this range, the
Viscometer is considered in calibration.
Table A2
Gram KUGram KUGram KUGram KUGram KUGram KUGram KU Gram KU
Brookfield Viscometers are guaranteed for one year from date of purchase against defects in materials
and workmanship. They are certified against primary viscosity standards traceable to the National
Institute of Standards and Technology (NIST). The Viscometer must be returned to Brookfield
Engineering Laboratories, Inc. or the Brookfield dealer from whom it was purchased for no charge
warranty service. Transportation is at the purchaser’s expense. The Viscometer should be shipped in
its original container together with spindles originally provided with the instrument.
For repair or service in the United States, return to:
Brookfield Engineering Laboratories, Inc.
11 Commerce Boulevard.
Middleboro, MA 02346 U.S.A.
Telephone: 508-946-6200 FAX: 508-946-6262
email: service@brookfieldengineering.com
For repair or service outside the United States, consult Brookfield Engineering Laboratories, Inc.
or the dealer from whom you purchased the instrument.
For repair or service in the United Kingdom, return to: