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Frequently Asked Questions
Viscometer SV10/100
Question
Temperture
Sensor plate
Calibration
Answer
General
-
What system does the SV Series apply in order to measure viscosity? Top
The SV Series vibrates its two sensor
plates like a tuning fork while keeping a constant frequency and
amplitude, and measures the driving electric current that is varied to
keep the constant vibration according to viscosity change during
measurement. The SV Series displays viscosity converted from the
measured driving electric current.
-
Do the sensor plates rotate?
Top
No. The sensor plates vibrate at 30Hz.
-
At what amplitude is the sensor plate vibrated? Top
At just about 0.4mm. Thus, it causes less damage to the structure of
sample.
-
To which part of the sensor plate should be covered with a sample
fluid? Top
The target level of immersion is the most
narrowed place just above the round part of each sensor plate. Adjust
this level to the level of the fluid surface.
-
Does it affect the measurement result if the immersion level of the
sensor plates change ? Top
Although it depends on viscosity of
each sample fluid, if the level changes by 1mm with SV-10 in low
viscosity range, measurement error of approx. 2-3%, and with SV-100 in
high viscosity range, approx. 10-15%, could be produced.
-
What amount of sample is necessary? Top
Just about 35ml for the standard Sample Cup is enough to perform
measurement.
- How
can I measure viscosity with a smaller sample amount? Top
offer you an accessory for smaller
sample measurement, the Small Sample Cup (AX-SV-34), enabling
measurement of only 10ml sample.
- Is
there any way I can measure kinds of highly acidic fluid in a small
amount? Top
We offer you the Glass Sample Cup
(AX-SV-35) for small sample measurement, another accessory enabling
viscosity measurement of approx. 13ml. If a sample amount need not be
small, a commercial glass beaker can be also used without problems.
-
What has most affect on viscosity measurement ?
Top
Temperature is one of the most
influential factors on viscosity. In general when temperature is low
viscosity becomes high, and temperature is high viscosity becomes low.
-
Is it possible to change the vibration frequency?
Top
No, it is not. This frequency is
unchangeably fixed at 30Hz. 30Hz is the most sensitive resonance point
that is obtainable within the measurable range of viscosity. In the
production line the vibration frequency is adjusted within +/-0.02Hz
to enhance the measurement accuracy.
-
Is it possible to set shear rate? Top
It is impossible under the system of the
SV Series. However, in measurement of Newtonian fluid the results are
not affected by setting of (in relation to the rotational viscometer)
what is called shear rate, or rotating speed of spindle, rpm. For
measurement of Non-Newtonian fluid, it necessitates a predetermination
of either shear rate or shear stress, which are not in proportion.
-
Is there any compatibility between the measurement results of
the rotational viscometer and the SV Series? Top
In case of the standard fluid, which is a
Newtonian fluid, conformity in the results is observed. In measurement
of Non-Newtonian fluid, the viscosity value measured at low rotational
speed with the rotational viscometer, since a rotational speed of
spindle, rpm, is determined for setting shear rate, may be approx. 10
times as high as that with the SV Series.
-
Why do the rotational viscometer and the SV Series
differ in measurement results of Non-Newtonian fluid?
Top
The difference in results is merely due to the
difference of their measurement systems, thus both results are correct
in their own ways. For example, if you change shear rate, as
measurement condition of rotational viscometer, by increasing the
rotational speed, rpm, the measured viscosity changes. This shows that
measurement results depend on measurement conditions and that those
results are both valid.
-
Why does the viscosity of a Non-Newtonian fluid change with time from
start of measurement? Top
Viscosity change of a Non-Newtonian fluid
appears as its physical structure is changed or damaged when stirred,
beaten or pressed with stress. In measurement with the SV Series,
viscosity usually decreases in the beginning as the vibration starts
breaking the fluid structure around the sensor plates, but then
stabilizes after a period time. In case of the rotational viscometer
it causes greater damage to fluid structure and takes longer to
stabilize the result in measurement than the SV Series does.
-
How long does a viscosity measurement take. Top
The SV Series displays viscosity just
about 15 seconds after pressing the Start key, and continues
displaying real-time measurement values from then on.
Temperture
-
Is it possible to measure sample temperature with the SV Series? Top
Yes. The SV series comes equipped with
a temperature sensor placed between the two sensor plates, which
enables constant accurate temperature measurement.
-
What temperature range does the SV Series cover? Top
Standard measurement ranges from 0 °C to
100 °C. For higher temperature measurement we are pleased to accept
special orders for a the temperature sensor usable up to 160 °C.
-
How can I change the sample temperature during measurement? Top
Use the Water Jacket (AX-SV-37) to
connect the temperature-controllable Water Bath. Or you can use a
heater to heat the sample during measurement. It is possible to
monitor changes in viscosity with temperature changes if you
refrigerate the sample before measurement and then heat it with a
heater or just leave it at room temperature during measurement.
-
What is the lowest temperature the SV Series can measure? Top
We guarantee the temperature measurement
down to 0 °C. SV Series displays temperature even down to 20 to 30 °C
below freezing, but we cannot guarantee the accuracy of +/-1 °C or
higher.
-
Is the temperature unit display selectable between Centigrade and
Fahrenheit? Top
Yes. Select the temperature unit °C or °F
from the function setting. You can choose a combination with the
viscosity unit of your choice.
Sensor plate
-
What is the sensor plate made of?
Top
It is made of gold-plated stainless steel SUS304.
-
Why is the sensor plate gold-plated?
Top
Because it protects the sensor plate from highly acidic fluids
during measurements.
-
How long does the sensor plate last? Top
It depends on the use conditions and
frequency of use. The sensor plates are basically not expendable
parts and can be used semi-permanently.
-
The sensor plate looks fragile. Is it easily bended or broken? Top
The thickness of the sensor plate is
approx. 0.3mm. It is much stronger than it looks. Although it may
yield when pressed or hit with great impact, you can recover it by
straightening it and use it without harming measurement accuracy.
-
What should I do if the sensor plate is broken?
Top
The sensor plate is replaceable.
After replacement, please perform calibration. Please note that
simply replacing the sensor plates for SV-10 with the sensor plates
for SV-100 cannot make model change since their shapes are
different.
Calibration
-
How often should I perform calibration?
Top
You do not have to regularly perform
calibration since usually the calibration values will not shift and
produce errors as a result. We recommend that you follow your
company protocol if it mandates regular calibration.
-
Is calibration difficult?
Top
The SV Series has user-friendly
calibration function. Just prepare the standard fluids. You can
choose from one-point calibration or two-point calibration.
-
Is it possible to correct input of incorrect values after a
calibration? Top
You can re-input correct calibration
values by performing another calibration. It is also possible to
recall the factory calibration values (SV-10 at 1mPas and 1000mPas /
SV-100 at 1000mPas and 10000mPas) that are stored in the nonvolatile
memory easily by using the “CLr” function.
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