UNITHERM ™ MODEL 1251
ULTRA HIGH TEMPERATURE DILATOMETER
- SALIENT FEATURES

(Technical Note #103)

· Superior to competition
¨Unique to our equipment

Furnace:

   Water cooled shell
   Water cooled end plates
   Water cooled current feed-throughs
   Carbon-fiber insulation
   Long-life, single piece heating element
   Gas purge swept sight windows to protect against deposits
   Vacuum and purge gas capability
¨ Anti-syphon safety exit trap
    Environmentally friendly, energy saving design, dumping no heat load to immediate environment
¨ Single range pyrometer covering 25 to 3000°C range seamlessly and without use of retractable
    thermocouples or dual pyrometers. (Standard range 25 to 2500°C)

Power Supply:

¨ Water cooled step down transformer for efficient, cool operation
¨ Water cooled thyristor power controller
    Phase angle and current limiters
    Small physical size

Safety:

   Furnace pressure relief valve
¨ Water flow interlock sensor
¨ Independent over-temperature sensor
¨ Dead computer detector
·  Software selectable safety features
·  Logical (in-software) software safety features

Dilatometer:

       Counterbalanced stage to lift out dilatometer
       Water cooled instrument platform
       Select-grade graphite; dilatometer matched construction pushrods
       Sample tilt-out protection
       Easy removal and exchange or sample holder components
¨    Dual sample (two independent) simultaneous, or differential operation
       Vertical configuration
¨    Optional range extension to 3000°C
· ¨ Critical parts fabricated from nearly-zero expansion lnvar
       (no need for expensive constant temperature circulators)
¨    Counterbalanced push-rod using static weights
·    TMA Operation (operational)
· ¨ Fully digital, absolute displacement transducer
· ¨ Long stroke coupled with high sensitivity, especially useful for sintering work

Temperature Programming:

¨ Digital adaptive temperature control which provides control to true sample
    temperature not to furnace temperature
·  Built in tutorial and simulation program
·  On-screen programming with entry checks, 26 segment program
    Variable heating rates within a broad range
    Variable dwell temperatures, 1° increments
    Variable soak times, 1 minute increments
·  Up to 98 stored programs, with quick review window
·  Up to 9 repeat cycles

Special Programs (Optional):

·  Controlled rate sintering cycles
·  Softening point determination

Data Analysis:

Fully automatic, computer controlled data reduction according to ASTM E228 procedures
·  Statistical evaluation of data and curve fitting
·  Computation of results in uniform intervals
      Percent expansion vs. temperature table
      Average coefficient vs. temperature table
      Instantaneous coefficient vs. temperature table
      Percent expansion vs. temperature plot
      Average coefficient vs. temperature plot
      Instantaneous coefficient vs. temperature plot
· ¨ Automatic calibration cycles with multiple (stored) calibration files