The CAL3K system uses the SMART CAL3K bomb vessel. The bomb vessel is the first of its kind, and is the heart of the CAL3K system. Its sophisticated design allows the temperature to be measured to six decimal places in degrees Celsius.

The vessel is an intelligent (SMART) vessel with a microprocessor built into its base.

The vessel is capable of recording: firing counts, identification and reconditioning data.

The lid assembly holds the crucible containing the sample for determination. Temperature sensors are built into the wall of the vessel for effective temperature measurement. The vessel is filled with up to 3000Kpa of oxygen for each determination. Measuring calorific values has never been this easy.

The bomb vessel is smaller than conventional vessels, which results in a larger heat capacity. Special attention has been given to a thermally balanced vessel design. Computer aided design (CAD) and computer simulation of heat transfer characteristics is used to achieve this.

The vessel has an oxygen volume of 0.21 litres (210ml), which allows for a 0.5g coal sample at approximately 30MJ/Kg.

The electronics and sensors are vacuum epoxy impregnated to prevent physical damage as well as moisture from entering the electronics. The firing wire is semi-permanent and only needs to be replaced when the wire is burnt or damaged.

The vessel measures the temperature and calculates the drift (first derivative) and stability (2nd derivative) every 6 seconds.