Short description

The ARES rheometer is a true strain-controlled instrument, where the application of strain and the measurement of stress is truly separated. The bottom tool is rotated by a motor, while the force rebalance transducer measures the torque response on the top tool. While not as sensitive as some modern stress-controlled rheometers, this machine still has many advantages:
  • Less influence of tool inertia on oscillatory measurements at high frequency.
  • Results in steady shear do not depend on tool angle, no problems with angle-dependent friction of air bearings.
  • Accurate stress-relaxation tests.

Things to remember

  • Before handling the tool:
    • turn off motor
    • set to transducer 2
  • Insert lower tool only if bath and tool are at the same temperature. (thermal expansion .. :-)
  • Do not change motor to dynamic mode with sample loaded.
    • (if absolutely necessary, you can turn off the motor, turn the lower tool to the "zero" position and then change to dynamic mode)
  • Do not use "Set Gap" in the Gap control panel before running "Zero Gap".
  • Do not leave the transducer in overload mode (click the yellow warning button)

Using the ARES

  • Get training
  • Reserve it
  • If anything unusual happens during use, please ask one of the people responsible for the rheometers. If the main air pressure drops below 70 psi, stop all measurements, do not touch the tools and contact one of the following emergency contacts:
    • Harvard facilities office: (617) 495-2840
    • Harvard Police (during the night): (617) 495-1212

Measuring Geometries

Geometry

Dimensions

Sample Volume (approx.)

Notes
Parallel plate 50 mm

  • 50mm Diameter
  • Variable Gap
 2 mL with 1 mm gap Shear gradient exists across the sample.
Cone/Plate 50 mm

  • Diameter: 50 mm
  • Gap: 0.0508 mm
 2 mL Constant shear profile.
Couette 34 mm

  • cup d: 34 mm
  • bob d: 32 mm
  • bob length: 33.2 mm
 13.5 mL Constant shear profile.

Large volume required.
Couette 17 mm

  • cup d: 17 mm
  • bob d: 16.5 mm
  • bob length: 13 mm
 3 mL Constant shear profile.
Double wall couette

  • Inside cup d: 21.54 mm
  • Outside bob d: 23.54 mm
  • Outside bob d: 25.58 mm
  • Outside cup d: 27.92 mm
  • Bob length: 28.5 mm/ul>
 6.5 mL Constant shear profile.

Home built tool.

Heavy.. sometimes problems with normal force overload.
Our ARES has two different transducer settings with the following torque ranges:
  • Transducer 1:
    • Low torque limit: 4e-7 Nm
    • High torque limit: 1e-3 Nm
  • Transducer 2:
    • Low torque limit: 4e-6 Nm
    • High torque limit: 1e-2 Nm
  • Please use transducer 1 only if you need extra sensitivity at low torques. Always switch to transducer 2 whenever you are handling the upper tool. Remember that too much force or torque on the upper tool can damage the transducers.
The ARES is equipped with a thermostat bath for temperature control. Depending on the fluid mixture used, we can achieve a temperature range between 10C and 100C. Make sure to use the right fluid mixture in the circulator for your desired range of temperatures.

Other information

Technical support

  • Patel Scientific is a company that specializes in servicing ARES rheometers, their support number is (908) 510-4407.
  • For support from TA Instruments, call (302) 427-4000.