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AC600 Semi-Automatic Isoperibol Calorimeter

Gross Calorific Content

Ideal for the measurement of calorific content in solid and liquid fuels, LECO’s AC600 semi-automatic isoperibol calorimeter sets the standard for future calorimetry instruments. Its semi-automated operation, combined with the use of thermodynamic TruSpeed®, obtains a rapid analysis of calorific content and increased instrument throughput without sacrificing accuracy or instrument precision. A new, ergonomically-designed, lightweight combustion vessel assures ease of operation while greatly reducing operator strain.


  • Enhanced automation for added productivity
  • Analysis in as little as 5-minute analysis without compromising accuracy or precision
  • Ergonomically-designed vessel promotes easy vessel handling, while enhancing the heat transfer rate
  • Integrated vessel charging station and depressurization ports equipped with quick-release handles speed vessel charging and depressurization process.
  • Intuitive software provides virtually unlimited storage space, simplified data handling, and compatibility with various Laboratory Information Management Systems (LIMS) 

Theory of Operation

The LECO AC600 semi-automatic calorimeter was developed to measure the calorific content of various organic materials such as coal, coke, and fuel oil.

The calorific value of a sample is determined by precisely measuring the heat released after combustion of the sample in a controlled environment. The heat released is proportional to the calorific value of the substance.

The sample is placed into a combustion vessel, which is pressurized with oxygen. The combustion vessel is automatically lowered into a water bath within the instrument known as a bucket. The bucket is sealed using an inflatable bladder. The cavity surrounding the bucket is known as the jacket and is also filled with water. The water temperature in the jacket is closely controlled at a precise set temperature (isoperibol calorimeter system). The sample is ignited and the temperature of the bucket and jacket water is measured by an electrical thermometer with a resolution of 0.0001 of a degree. A measurement of the water temperature inside the bucket and jacket is collected every second. The results can be corrected within the software for any spiking, nitrogen, sulfur, moisture, and ash content if necessary. Two options for analyzing data are available. A simple temperature difference may be chosen by the user (Delta T mode), in which calorific values are determined by a simple maximum temperature rise of the bucket. The user may also choose to use a thermodynamic model (TruSpeed mode) that has been developed by LECO to model heat exchange within the AC600 system. The TruSpeed mode takes into account heat capacities of the system's components along with corrections for energy transfer within the system. The TruSpeed mode enables the AC600 to attain rapid 5 minute analysis times without compromising the accuracy or precision of the calorific result.

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AC600 Series Details

AC600 Semi-Automatic Isoperibol Calorimeter
  • AC600 with standard vessel
  • AC600 with halogen-resistant vessel
  • Dual AC600 with standard vessels
  • Dual AC600 with halogen-resistant vessels
  • Standard vessel for wire or thread ignition
  • Halogen-resistant vessel for wire or thread ignition
  • Recirculating water chiller

Featured Application
Gross Calorific Value Coal [PDF]
Product Literature
AC600 Series [PDF]

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