The cost‐effective ARC® 244 is designed to safely measure the amount and rate of heat release associated with the processing or storage of chemicals within a container volume between 1.5 ml and 8.5 ml. This is the calorimeter which uses the same design as the first ARC® system developed by DOW for those customers interested in keeping the same platform.
This information is vital in developing and evaluating processes to ensure safe operation and to prevent thermal runaway which can have devastating effects.
The Accelerating Rate Calorimeter 244 (ARC® 244) technology is integral to designing inherently safer batteries as well as measuring energetic materials used in such products as explosives, propellants, and air bags.
Major Features and Benefits
- Tube heater reduces heat losses due to reflux
- Windows XP™ operating system standard
- Smaller footprint
- Lift mechanism for calorimeter top
- Experimental wizards for easy test set-up
- Power Compensation Module (optional)
- Increased safety and interlock features
- Operation modes:
∙ Heat-Wait-Search (primary mode of operation)
∙ Iso-Fixed technique
∙ Iso-Track technique
∙ Ramp mode for fast screening of unknown samples
- With VariPhi®
∙ Heat-Wait-Search, with Phi = 1
∙ Constant power
∙ Constant heating rate
∙ Fire exposure
∙ True isothermal mode
- Operating Test Cell Temperature Range:
RT to 500°C
primary mode of operation
Iso-aging techniques for studying storage conditions/auto-catalytic reactions
- Ramp mode for screening unknown samples
- Scanning Mode with Power Compensation Module
- Isothermal Mode with Power Compensation Module
- Test cell materials for spherical vessels with a wall thickness between 0.4 mm and 5.1 mm:
(Volume: 1 ml to 130 ml)
- Test cell materials for tube-type vessels with a wall thickness of 0.4 mm and 0.7 mm:
(Volume: 0.1 ml to 9 ml)
Comparison to legacy data
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 operational modes such as Heat-Wait-Search, Iso-Fixed, or Iso-Track.
VariPhi®’s key features in Accelerating Rate Calorimeters (ARC®) mode:
- 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.
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
Lithium Ion is becoming the technology choice for HEV, PHEV, as well as many stationary applications. The White Paper explains how the unique combination of adiabatic and isothermal testing are best suited for looking at thermal runaway of cells within packs for the design of safety features and to minimize the risks of internal shorting leading to thermal runaway.