"Building the Case for Reconditioned Rheometers."

"Building the Case for Reconditioned Rheometers."
BUILDING THE CASE FOR
RECONDITIONED RHEOMETERS
H
Jeshwanth K. Rameshwaram, Ph.D.
Tien T. Dao, Ph.D.
Chris Torres
istorically only corporate rheologists performed analyses
that required expensive, research-grade rheometers, but
today many other scientists and engineers use rheology
to solve a variety of industrial problems. These solutions often
require complex material characterization beyond the capabilities
of a typical rotary viscometer.
Although the cost of analytical instrumentation has dropped
significantly over the last 30 years, the price of research
rheometers remains high, hindering the evolution of broader
rheological use.
ATS
RheoSystems offers reconditioned
STRESSTECH and NOVA rheometers for
40-60% of the cost of new researchgrade rheometers. After extensive reconditioning and
calibration, these top-of-the-line instruments once again
perform with impressive accuracy, matching original
specifications and allowing a broader range of scientists and
engineers access to the key rheological data only available
with a research grade rheometer.
During reconditioning, we adjust or replace all electrical
components, test the air bearing and motor package, and
calibrate the environmental cell. The instrument is tuned to
perform as well as it did when it first left the factory. Then we
install updated electronic and computer control components
to ensure better communications, faster startup, and
improved overall performance. All reconditioned instruments
come with a certificate of calibration and a one-year
warranty.
As research-grade instruments, these rheometers perform far
more than basic deformation and viscosity property tests.
Oscillatory motion of the spindle, rather than simple
rotational motion, enables testing of material properties such
as the modulus of elasticity, while the incorporation of an air
bearing provides precise measurement and control of normal
force and torque.
Table 1 — Technical specifications for rheometers
Torque range
Torque
resolution
Normal force
range
Angular
Velocity
Angular
Resolution
Frequency
Range
Temperature
Range
Dimensions
(L × W × H)
Weight
STRESSTECH
20 nNm to 50 mNm
NOVA
3 nNm to 200 mNm
0.1 nNm
0.1 nNm
0.002 to 50 N
0.001 to 50 N
0 to 320 rad/s
0 to 600 rad/s
0.03 μrad
0.03 μrad
1 x10-7 to 100 Hz
1 x10-7 to 100 Hz
Stand: −20 to 150 °C
Opt: −180 to 400 °C
−180 to 450 °C
457 × 406 × 533 mm
600 × 400 × 600 mm
36 kg
40 kg
Table 2 — Research Rheometer Viscosity Ranges
Measuring
System
Specific Viscosity Range
Minimum
~ 5 cP (40 mm
Parallel Plate
diameter plates)
~ 5 cP (40 mm
Cone & Plate
diameter plates)
1 cP (narrow gap
Cup and Bob
≥ 0.5 mm gap)
Vane Tool
~ 5 cP
Maximum
~ 10,000,000 cP
(≤15 mm diameter plates)
~ 10,000,000 cP
(≤15 mm diameter plates)
~ 30,000 cP
~ 100,000 cP
ATS Rheosystems, a division of CANNON Instrument Company®
Rheometer calibration is crucial to achieving reliable and
accurate results. To this end, we at ATS calibrate all
instruments using NIST traceable oil standards supplied by
Cannon Instrument Company®. Figure 1 presents the actual
viscosity profiles of water and four oil standards that we
measured using a reconditioned STRESSTECH rheometer. This
data shows the high accuracy of the reconditioned
rheometers across a wide range of viscosities: from water
(0.9 cP at 25 °C) to a 12,000 cP oil standard.
Building the Case for Reconditioned Rheometers
STRESSTECH FEATURES
The STRESSTECH HR excels in research and product
development with high precision and a wide dynamic range
due to an advanced normal force sensor and non-contacting
air bearing. It is designed around a modular base with
optional accessories to suit a wide variety of applications.
•
•
100000
•
1000
•
Viscosity cP
10000
100
•
•
10
•
1
•
0 .1
1
100
10
1000
10000
Shear rate 1/s
Water (0.9 cP)
9 cP oil
98 cP oil
970 cP oil
12000 cP oil
Figure 1 — Flow profiles of water and oil standards at 25 °C
Figure 2 presents the oscillation frequency sweep data of a
polydimethylsiloxane (PDMS) standard using a reconditioned
STRESSTECH rheometer. All viscoelastic properties for the
PDMS are within acceptable limits for the instrument.
10
+5
100
1 10
+5
5 10
+4
2 10
+4
1 10
+4
5 10
+3
2 10
+3
1 10
+3
NOVA FEATURES
The NOVA Rheometer features a unique "Net- Zero" bias
bearing system. This null balance system allows for NanoTorque and Nano-Strain measurement control and analysis.
•
•
•
+4
G', G" Pa
60
40
10
+3
20
10
+2
10
-2
10
G'
G"
-1
+0
10
Frequency rad/s
Phase
10
+1
10
+2
0
Phase degree \ Viscosity * Pa·s
80
10
Viscosity
Figure 2 — Oscillation dynamic frequency sweep of PDMS
standard at 25 °C
Patented differential pressure normal force sensor
Torque range from 20 nNm to 50 mNm with an
option to extend to 100 mNm for certain test
parameters
Automatic gap setting for controlled, reproducible
sample loading and convenient trim gap setting
Automatic compensation for thermal expansion of
measuring systems
Automatic inertia compensation
Fast oscillation measurement program to analyze
rapid changes in a material
Special geometries such as serrated plates and vane
tools are available in addition to custom
measurement systems
RheoExplorer software offers a Windows® user
interface with multitasking capability, data analysis,
and exportation
•
•
•
Patented differential pressure normal force sensor
Innovative, low inertia, drag cup motor utilizing
"Feed Forward" strain and shear rate control
Torque range from 3 nNm to 200 mNm with
opportunity for extension down to 1 nNm and up to
230 mNm for certain test parameters
Strain resolution of 0.01 µrad
Special geometries such as serrated plates and vane
tools are available in addition to custom
measurement systems
Ethernet communication, high-speed USB port and
RheoExplorer software
For additional information contact:
ATS RheoSystems, A Division of Cannon Instrument Company
2139 High Tech Road, State College, PA 16803, U.S.A.
tel.: 814-353-8000; e-mail: info@atsrheosystems.com
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