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Furnace temperature control system

Countless manufacturing processes require, in one or more of their stages, the temperature control of an industrial furnace.Having suitable sensors is essential in these stages, where temperature is a key factor. An industrial furnace can reach quite divergent temperatures, so using the same kind of indicator will not always be possible. We have irreversible labels, crayons and heat-sensitive paints to measure the temperature inside the furnace and, what is more, directly on the parts being manufactured. Unwanted temperature fluctuations can, therefore, be detected in inaccessible areas.

Main products for temperature control in industrial furnaces

Temperatures we can control with irreversible thermometers

When the temperature control range of an industrial furnace does not exceed 290 °C, we can use irreversible heat-sensitive labels. These indicators are the most cost-effective, simple and accurate option we can use – depending on the temperature range. Choose a clean, dry area of the part where to stick the label before placing it inside the oven. At the end of the process, we will see what has happened. We can even< remove the label to attach it to a report if needed for quality control purposes.

Temperatures we can control with temperature crayons

When labels cannot be used – either because the parts are too small and there is not enough space to stick them on, or because the temperature reached is over 290 °C – a good temperature control system for a furnace is the use of heat-sensitive crayons. With this option, we will cover a temperature range of 120 to 600 °C. It is also quite easy to use. Because it is a wax crayon, we can mark the pieces conveniently without needing much space. In this case, if we have marked a part that we will include in our sales inventory, we will have to remove the line, which can be done by simply using sandpaper – manually or mechanically. If we were able to place a part made of the same material or a testing part in the same furnace, we could skip this step.

Temperatures we can control with heat-sensitive paint

There are furnaces in which the temperature reaches 1300 °C or more. In such harsh temperatures, the use of paper labels or crayons is ruled out. To control the temperature of an industrial furnace that reaches such high temperatures, we will use thermochromic paints, which are designed to withstand this heat, and also to change colour according to the temperatures reached. These work conditions make the situation somewhat complicated, and readings will require the operator to have some prior information before using this type of paint. The paint is supplied with all the information needed to achieve maximum performance and to identify the colours before starting work. The documentation includes:

  • Time/Temperature calibration chart.
  • Colour chart: it is made based on Nimonic 90. Therefore, the operator must make some previous painting tests on the material to be controlled in order to build the “real” specific colour profile.
  • Thickness of the paint layer to be applied.
  • Safety temperature to avoid early colour changes.

Advantages of internal thermal control in an industrial furnace

  • Detecting possible faults such as leaks, hot spots or temperature imbalances.
  • Accurately diagnosing the temperature.
  • Reducing extra costs on fuel or electrical power.
  • Following the established quality guidelines.
  • Improving the quality of the final product and ensuring customer satisfaction.