AC600 Semi-Automatic Isoperibol Calorimeter


Test vessel

LECO calorific vessel has reduced weight, rounded shape, with cap secured within 1.5 revolutions. It optimizes heat transfer rate and easy handling for quicker vessel preparation.


The calorific value is one of the most important quality parameter of solid fuels, like coal, coke and biomass as well as waste materials. 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 LECO AC600 semi-automatic isoperebol calorimeter sets the standard for future calorimetry instruments and was developed to measure the calorific content of various organic materials such as coal, coke, biomass and fuel oil.. 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, integrated vessel charging station offer convenient operation while greatly reducing operator strain.

Windows®-based operating system allows settings of all test parameters including special required ASTM or DIN calculations and corrections.



  • Fastest calorimeter with 5.5-minute analysis times without compromising accuracy or precision
  • Automated features and ergonomic design enhance productivity
  • Integrated vessel charging station and quick-release handles simplify operation


Two operational Modes for calculating results are available. In standard DeltaT Mode the simple temperature difference calculation for calorific values determined by a simple maximum temperature rise of the bucket. The advanced TruSpeed Mode is based on a unique thermodynamic model developed by LECO that takes into account heat capacities of the system’s components along with corrections for energy transfer within the system. The TruSpeedTM mode enables the AC600 to attain rapid 5.0 minute analysis times without compromising the accuracy or precision of the calorific result. Optional two-vessel operation maximizes throughput allowing you to prepare the second vessel and sample while the current sample is being analyzed.


  • Reduced vessel weight with rounded surfaces promotes easy handling of the vessel, while enhancing the heat transfer rate of the vessel
  • Each vessel has engraved serial number for traceability
  • All water filling, draining, and volume measurement, as well as control of the addition of heating and cooling water, are automatically handled within the instrument
  • User-defined calculations support custom calculations or conversions for data and results.
  • •Thermochemical basis corrections for: Fuse, Nitrogen, Sulfur, Spike, and Ash.


LECO’s versatile instrumentation can be used to perform a wide range of applications. Please find below a selection of application notes for the most popular applications. Contact our sales and application specialists for more details.

Gross Calorific Value in Coal

The gross calorific value of coal, a solid fossil hydrocarbon fuel material, is most often used when calculating the total calorific value for a quantity of coal for fuel value purposes, or when determining the classification rank of the coal material. Learn more...

Metallurgical Coke

Gross Calorific Value in Metallurgical Coke by AC600. Ref: 203-821-473Learn more...

Petroleum Coke

Gross Heat in Petroleum Coke by AC600. Ref: 203-821-467Learn more...

Gross Heat

Gross Heat in Fuel Oils and BiomassLearn more...

Options & models


Various options are available for this product. Contact our sales and application specialists to select the right configuration for your application.
Recirculating water chiller A recirculating water chiller is required for the operation of the AC600
SmartLine diagnostic LECO's convenient internet-based Remote Diagnostics system


Each instrument can be configured to meet your individual lab needs. Contact our sales and application specialists to select the right configuration for your application.
AC600SC AC600 with standard vessel and PC
AC600SHC AC600 with halogen-resistant vessel and PC
AC600DC Dual AC600 with standard vessel and PC