Furnace

Non-contact Temperature Measurement for Optimal Fuel Efficiency

Furnace applications

In today's international competition, a manufacturer of heavy clay products or refractories is forced to deal permanently

with the reduction of production costs and the increasement of the efficiency of the production plant.

It only makes sense to influence such cost-intensive operating parameters which have the greatest savings potential:

reducing energy consumption and minimizing the reject rate. The kiln temperature profile has a significant influence on the amount of fuel required and the quality of the yield. In this respect, it is of utmost importance to precisely monitor the temperature of the clay product during the firing cycle using accurate measuring instruments.

Advantages of Non-contact Temperature Measurement

Today we see a trend toward equipping new kilns (and retrofitting older ones) with pyrometers. Pyrometers determine the temperature of an object of its infrared radiation. They - as opposed to thermocouples - measure the temperature from a distance directly at the surface of the product, and thus give the most accurate representation of the real heating process taking place within the kiln to enable optimal process control. Thermocouples merely measure the air temperature

within the kiln. Their measurement reading will deviate significantly from the actual temperature of the product and will furthermore depend on variables such as air flow and kiln setting.

Thermocouples react sluggishly to thermal fluctuations whereas pyrometers instantly indicate temperature changes. A pyrometer immediately detects the lower temperature of a new batch entering the kiln so that the firing process can be adjusted accordingly. Tighter control of the optimal kiln temperature profile will result in a significant reduction of fuel consumption.

Since effective process control depends on reliable temperature measurement, the sensor drift that thermocouples experience while in service is a major drawback of thermocouple use. Sensor drift will creep up unnoticeably and measurement errors will not be recognised until defects are discovered on the products exiting the kiln.

Process intervention is only possible at a very late stage in the firing process.

Pyrometers have the advantage of not being subject to drift. Process control based on reliable pyrometer readings results in a considerably lower reject rate. Furthermore, pyrometer measurement is a non wearing system meaning that no follow-up costs will be incurred. Today the purchase price of a pyrometer system hardly exceeds the initial cost of a thermocouple. With a view toward operating cost reduction it is wise to switch to pyrometer measurement.

Portable Instrument

The portable pyrometers of the CellaPort PT series have been well established for quick temperature checks. These

devices feature a precision through-the-lens optic which is focusable and interchangeable.

The target marker indicates the exact measurement spot and thereby facilitates precise aiming through the furnace opening. The ATD function makes operation easy because only the hot object must be targeted for measurement. The data logging starts automatically. After 3 seconds an acoustic signal marks the end of the measurement. A patented traffic

light status indicator, that is visible in the through-the-lens-sighting, also supports the recognition of the hottest point.

The PC connection cable and the analysis software CellaView, which are included in the scope of supply, offer the possibility to record and evaluate temperature and time courses over a longer period.

Conclusion

Today, modern pyrometers can easily replace thermocouples for temperature measurement tasks in furnaces. Pyrometers measure reliable over many years, do not cause consequential costs and reduce scrap and fuel consumption. Beside the stationary measuring systems of the PK series, the portable pyrometer CellaPort PT is used for quick control measurements. Only by continously investing into new, improved and cost-saving technologies, one is able to stay competitive in the long term.