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Doubt's regarding authenticity can be arise
about design of the Rheometer on being available indigenously, such point are
required to be clarified for the above doubt's?
Q1.whether design of the
machine is having standard norms?
Q2.Are there main
feature's as per the above standard?
Q3How do you compare
"MV" OSCILLATING DISC RHEOMETER with brand Rheometer?
Q4.How "MV" ODR
Rheometer is compared to the above mentioned unique feature
Q1.whether design of the
machine is having standard norms?
Ans1. Yes, 180-3417:1991 (E) Rubber - Measurement of
vulcanization characteristics with the Oscillating Disc Rheometer.
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Q2.Are there main
feature's as per the above standard?
Ans2.Disc & Dies: Made from non-deforming
tool steel with minimum Rockwell hardness of 50 HAC. The geometry of the Disc
& Dies is detailed in the standard.
a) Die Closure: Dies shall be closed and held closed during the test by a
pneumatic cylinder with a
force of 11.0 +/- 0.5KN.
b) Disc Oscillation: Frequency 1.7 Hz +/- 0.1 Hz. Angular displacement 1.00. +/-
0.02° or 3.00° +/- 0.03° .
c) Torque measuring system: A device which produces a signal i.e. directly
proportional to the torque required to turn the disc shall be used to measure the torque on the disc.
d) Recording: The Recorder shall have a speed of response of full scale
deflection on the torque
scale of one
second or less. The torque shall be recorded with an accuracy +/- 0.5% of
the torque
range. Three torque ranges of 0 to 2.SNM, 0 to SNM and 0 to 10NM, shall be provided.
e) Temperature measurement:
The temperature measuring system shall enable
the temperature of the die to be measured to
within +/- 0.1°C. The Dies shall be mounted in electrically heated aluminum platens. Temperature at steady state be within +/- 0.3°C. On inserting test
piece at 23°C
+/- 5°C, the temperature recovery should suffice so that the temperature of the dies
is +/- 1°C of the set temperature within two minutes of the start of the test.
f) Torque measuring system: Shall be calibrated by means of masses or by a
standard torque system such as a calibrated torsion spring
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Q3.How do you compare
"MV" OSCILLATING DISC RHEOMETER with brand Rheometer?
Ans3 TO ANSWER THIS QUESTION IT WILL BE BETTER IF WE
LOOK AT THE HISTORY OF IMPROVEMENT IN THE ORIGINAL RHEOMETER WITH RESPECT TO
CERTAIN SPECIAL FEATURES :
A. MECHANICAL :
1. Structural: In older models, the dies are open to the ambient atmosphere
resulting
in poor temperature control and poor
recovery of temperature. For this
the dies in later design is housed in a
Cabinet with shield controlling the
access to the dies. This resulted in better
temperature control and
recovery during the test.
2. Main Bearing: In older models the bearing on which rotor oscillates is near
to the
heated region of the sample and also within
the measuring system. In
later models the bearing is located away
from the heated region and is
out of the measuring system. This resulted
in less repair and maintenance
required due to wearing of the bearing. It
also resulted in decrease in
frictional torque during testing.
3. Clamping of Rotor: In older models the Rotor is clamped mechanically by means
of a draw
bar system. In later models this has been
replaced by a pneumatic cylinder
thereby imparting consistent clamping
pressure on the Rotor shaft.
4.Torque measurement: In older models a Torque arm strain gauge is used to
measure force
required for maximum displacement. This is
replaced in later model by a
Torque Transducer positioned immediately
below the rotor. This resulted
in direct torque measurement of the rotor.
In older models the HALL
effect switches is used to measure torque
signal at maximum
displacement only (2 readings per
oscillation). Whereas in later model an
Encoder system is used to read 16 points
per oscillation thereby
increasing the efficiency.
5. Temperature Control: In older models a separate solid state Thermister-sensing,
time
sequence proportional controller with
integral cycle firing is used. This
has been replaced in later model by
Micro-processor and the control is
under the Software. This has resulted in
better accuracy of +/- 0.2.C
compare to +/- 0.5 .C. The temperature
recovery which was 4.5 to 6
minutes to set temperature, in older models
has improved to 50 to 60
seconds in later models.
6. Recording: In older models recording is by means of flat bed strain gauge
recorder.
The record of torque against time is on a
graph paper and by varying the
X-Axis and Y-Axis, an appropriate graph is
obtained. The results are
manually calculated. In later model the
data is collected by built-in
micro-processor and the results are
automatically computed at the end of
tests and a print out is given out. There
is capability of enhancing this
with an additional software thereby one can
do other statistical analysis
of the data.
7. Result Variation: As per "Rubber World" 1990 January article "
New Rheometer and
Money Technology" by Patrik J.
Di Mauro, Monsanto Company, and J. De
Rudder and J.P. Etienne, Monsanto
-Europe, one can appreciate that the
results variation between original
model and later models is quite
substantial especially the time
values. This is purely because of better
temperature control and recovery.
Tests conducted on a SBR compound
at 177°C. in 50 new machines of each
type i.e. R1008, ODR 2000 and MDR
2000, the difference can be
summarized as follows:
7 a) Torque Values: ML is lower in ODR 2000 then R1008, MH is slightly higher in
ODR 2000
then R1008. ML & MH are much
lower in MDR 2000 due to different design
of the machine and the dies.
7 b) Time Values: Time values are faster in ODR 2000 against R100 and R1008. In
MDR
2000 it is much faster.
7 b) Sensitivity: The sensitivity of the machines with respect to
variation in ingredient
was also assessed and it was found
that the difference between R 1008,
ODR 2000 and MDR 2000 was
insignificant. Any difference noticed was
purely due to better temperature
control and recovery.
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Q4.How "MV" ODR
Rheometer is compared to the above mentioned unique feature
Ans4. 1. The Dies are enclosed in a Cabinet with
shield for access to the dies. The shield is pneumatically operated.
2. The Main bearing is away from the heated region and out of the measuring
system. Thereby reducing the frictional torque and increasing the sensitivity of
the system. The repair and maintenance is like wise reduced.
3. The Clamping of the Rotor is by means of pneumatically operated cylinder
thereby clamping it uniformly through out the test.
4. The Torque is measured by means of a Torque Transducer placed in line with
the main shaft holding the rotor thereby measuring the torque accurately. The
signal from the torque transducer is processed by the Computer to compute and
record the value against time. This is displayed in real time on the monitor.
5. The temperature is controlled by two independent PID controllers with auto
tune facility to provide with accurate and consistent temperature control
throughout the test. The accuracy is : 0.3 to 0.5°C. and temperature recovery
to the set point is within 60 to 90 seconds.
6. The temperature and the torque signals are displayed and recorded by the
computer and the result is automatically computed at the end of the test. There
is built in customized software "MV-SOFTWARE" which also stores the data
of each tests in the hard disk, the data can be retrieved individually or in
compatible group for display in the form of multiple graph, the stored data can
be statistically and graphically analyzed to bring out meaningful and result for
assessing the quality, each result can be qualified by upper/lower limits
thereby setting up a statistical quality control.
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