Adiabatic Reaction Calorimetry

Accelerating Rate Calorimeter 254 (ARC®)

 

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VariPhi™ is a controlled variable DC heater used in Accelerating Rate Calorimeters (ARC®) to provide the most accurate simulation of real-world thermal environment.
VariPhi™’s sophisticated calibration software regulates and records the amount of energy supplied by the internal heater.
VariPhi™ enables precise measurement of heat, pressure, and activity within a sample, avoiding the need for complicated mathematical corrections.


VariPhi™ in Accelerating Rate Calorimeters(ARC®)

The Accelerating Rate Calorimeter heaters (acting as guard heaters) provide a well controlled near-adiabatic environment for the VariPhi™, bomb, and sample system. This allows the sample to be tested in the standard Accelerating Rate Calorimeters(ARC®)operational modes such as Heat-Wait-Search, ISO-Fixed, or ISO-Track.


VariPhi™’s key features in Accelerating Rate Calorimeters mode include:

• The internal heater compensates for the heat lost to the sample bomb during an exotherm.

• The user can define the thermal inertia or PHI (Φ) for the test. The heater returns all or part of the heat lost to the bomb wall to the sample. A user can define the exact thermal inertia at which to run the test.

• Tests can be run at the exact thermal inertia at which they will run in the plant or storage container.

• Sample heat capacity is measured as a function of temperature.

• Kinetics that are dependent on thermal inertia, such as competing reactions that cannot be compensated for mathematically, are no longer a problem.

• Thermal inertia can be corrected without having to extrapolate kinetics from overlapping and multiple reactions.

• Data obtained will directly correspond to actual run or storage conditions making it easier to relay the information to non-calorimetry specialists.

VariPhi™ in Scanning Mode

By using VariPhi™ as an additional heater, the user can run ramp tests with the Accelerating Rate Calorimeter (ARC®) that deliver improved information about the activity in a sample.
By operating in scanning mode, VariPhi™ can measure exothermic and endothermic activity, heat capacity, and pressure within a sample, faster and more cost effectively than a standard differential scanning calorimeter.

In scanning mode, VariPhi™ provides the following key features:

• Faster data collection on exothermic activity than Heat-Wait-Search tests

• Heat capacity measured directly as a function of temperature

• Enhanced measurements and capabilities over traditional DSC analysis

• Endotherm activity

• Pressure data

• Ability to inject sample

• Ability to stir sample

• Ability to set thermal inertia for direct real-world comparison

 

General

Technique

Applications

Accessories

Literature

Videos/Webcast