Process Temperature Control Rings PTCR Part 3/6 – Application areas and temperature conversion table

PTCR überwachen und dokumentieren Ofenbedingungen
Photo: Robert Wiezorek,


After laying the foundations for process temperature control rings in part 1 and 2, we would like to introduce you to our current news about application of the PTCR and the correct use of the temperature conversion table.

Did not read part 1 and part 2 of our newsletter? 

PART 1: Here you can find all details about ring types, right choice and advantages of PTCR (Points 1-4).

PART 2: Here you can find all details about thae application, soak time and atmosphere (Points 5-7).

8. When to apply PTCR?

Because of its specific properties, PTCR has a wide range of different applications at different conditions. It is a perfect tool for the determination and maintenance of the exact heat treatment of the product.

The main function are:

A) Process control and optimization

B) Trouble shooting

C) Yield improvement

D) Improvement of product quality

E) Reduction of inspection time and costs

F) Quality assurance 

A) Process control and optimization

The most frequent use of PTCR is in optimizing and managing the firing processes to achieve the optimal quality and to assess the thermal performance and characteristics of a kiln/furnace.

The way of working is to make a number of runs with different settings of the parameters temperature and time. This method is followed whenever a new product or process has to be introduced, to determine differences in the thermal characteristics of new kilns/furnaces, or to calibrate the kiln/furnace after maintenance.

B) Trouble shooting

This is one of the traditional applications of PTCR: malfunctioning of (parts of) the equipment. The ring is used to make a mapping of the kiln/furnace by ring temperature (RT) in order to localize positions with different thermal behaviour. After root cause analysis a proper corrective action can be taken to solve the problem

C) Yield improvement

Once the mapping of the thermal characteristics is available, one has the possibility to further fine-tune the process settings and optimize the yield. This will also lead to optimization of the energy consumption (see Figure 1).

Kiln/furnace temperature before and after using PTCR

Figure 1: Kiln/furnace temperature before and after using PTCR

D) Improvement of product quality

Through using the PTCR, the process is controlled in a much better way. Thereby the scatter of the productquality of the products is minimized. This means that the quality control of the products can be reduced as a start and may eventually be reduced further to sampling level only or even abandoned completely. Rework (if applicable) is reduced.

E) Reduction of inspection time and costs

The improved processing leads to the reduction of the number of products that have to be inspected. The only thing left is the measurement of the rings to monitor the process. In time the sampling rate maybe reduced to a bare minimum, reducing the inspection effort to a minimum, whilst guaranteeing an excellent process quality.

F) Quality Assurance

Process control, as formulated in ISO 9001:2015, nowadays can only be achieved by virtue of the availability of an objective means to monitor and control firing processes. PTCR provides this objective method.

9. How do I use the temperature conversion table?

The shrinkage of the diameter of the ring has to be converted into the Ring Temperature (RT). This table is updated for every batch of rings to be delivered, it means that both the product and the conversion table have a unique relation.

The respective diameters are compared with temperature specifications. Basically, this is not a „temperature“, but a thermal parameter that depends on time and temperature. The RT does for example not reflect the maximum temperature of the firing process, and does not correspond to the real kiln/furnace temperature, because the PTCR accumulates the absorbed heat quantity over time.

In case if your measurement results do not correspond to the temperature table, please check first if the correct table has been used. The batch information can usually be found at the bottom right of the temperature table, the ring type specification-top left.

If your results are outside the range of the table, the ring either does not have absorbed enough heat, or even absorbs too much heat.  Please contact us in such cases for individual advice. To support you specifically, we need information like maximum temperature, holding time and atmosphere. These factors have a strong influence on the shrinkage of the rings during the firing process! Please read our previous Newsletter Part 2.

Download Datasheet PTCR

In the next part 4/6 you will read:

  • How do I preheat PTCR and when is it necessary?
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