Bespoke thermocouple assemblies are 6m long

In support of current efforts to reduce carbon emissions, FP Temperature Sensors, a trademark of Ametek Calibration Instruments, has manufactured and supplied 6m long versions of its AMK thermocouple assembly sensors for use in the production of 'green' electricity and heat by burning biomass. The sensors were commissioned by Energi Randers Production, suppliers of electricity heating and water in Randers, Denmark, following close co-operation with Ametek Calibration Instruments.

The sensors, which conform to standard class 2 according to IEC 584 thermocouple type N, are supplied with a steel protective tube and an interchangeable ceramic inner tube. They are mounted through the top of the boiler furnaces to a depth of approximately 700mm and are used to monitor temperatures of around 1200-1300degC as part of a new flux firing system.

Olive cores and meat and bone meal are used as the fuel, so temperature control is critical, because the biomass must be ignited so that it burns at once to avoid possible gas explosions. In addition, a high temperature is required to ensure that any spores or bacteria from the fuel are destroyed and that any dioxin resulting from the process is completely burned.

The fuel enters the two boilers on a conveyor belt to ensure continuous combustion. More than 100 tons of biomass is burned per 24 hours. Each boiler is equipped with two of the special sensors, and a spare was supplied for use when a sensor is re-calibrated. The sensors were factory calibrated and will require only annual re-calibration. In view of the length of the sensors, an innovative system has been devised to allow the sensors to be exchanged for recalibration while the boiler continues to operate.

FP Industrial Temperature Sensors' product line includes a comprehensive range of thermocouple assemblies and resistance thermometers, measuring inserts, thermocouples (of precious as well as base material), thermocouple wire, extension wire, temperature transmitters and portable digital thermometers.