The Company – About Us & Our History Since 1983

Learn more about thermo-control Körtvélyessy GmbH. Since 1983, we have been developing drift-free thermocouples and high-precision oxygen probes.

A Success Story Since 1983

The Beginning

thermo-control was founded in April 1983 by Dr. László Körtvélyessy in Kleve on the Lower Rhine. Having fled Hungary in 1971, he worked as a research associate at Degussa. In 1974, he took on a leadership role as a developer at Ipsen in Kleve. In addition to many other patents, three principles led to a technical and economic breakthrough in temperature measurement.

The first is , which redefines the origin of thermoelectric voltage. In short, most of the voltage is generated at the highest temperature gradient.

is derived from the model above. It addresses the of thermocouples, which has been a significant problem in heat treatment to date.

Through experiments and calculations, Dr. Körtvélyessy adjusted the diameter of the two thermocouples. Aging still occurs, but now both wires age at the same rate, ensuring that the correct thermoelectric voltage is always generated.

involves the use of very thin, separate ceramic protective tubes in a connection head—in contrast to the thick ceramic protective tubes that were, and still are, commonly used—as well as the use of a blank tube equipped with a test thermocouple for monitoring purposes.

thermo-control thermocouples can therefore be checked without hesitation during operation, saving both time and money.

The company logo was also derived from this model:

The technological breakthrough lies in the material's very high resistance to thermal shock and, even more importantly, its fast response time, which is due to improved heat transfer made possible by the thin wall thicknesses.

In addition to these three main principles, continuous improvements have been made to the models in order to build thermocouples that are as durable and reliable as possible. To this day, thermo-control remains the only supplier offering a 4-year warranty and a fleet of thermocouples that, on average, last more than 10 years and break in 99.8% of cases due to external mechanical forces.

In 1987, Dr. Körtvélyessy launched the second product line: the oxygen probe

Oxygen probes are based on Nernst’s law, which states that a concentration gradient separated by an electrolyte generates a voltage. This physical law applies to all oxygen probes; however, it is up to the probe’s design to maintain constant conditions. As with thermocouples, Dr. Körtvélyessy introduced technical innovations here as well, which made the thermo-control oxygen probe an outstanding product. The response time, reliability, and robustness of thermo-control oxygen probes are currently unmatched.

Another development brought the world's only vacuum-tight oxygen probe to the market. This probe is particularly well-suited for low-pressure carburizing furnaces.

Thermocouple Applications

Dr. Körtvélyessy summarized his extensive experience in practical temperature measurement in his book *Thermoelement Praxis*. The book became a standard reference work for all practitioners in the field of temperature measurement.

The state of the art in temperature measurement and heat treatment is presented clearly and, as usual, with a practical focus, using the proven triple thermocouple as an example. New additions include Type N thermocouples and their potential applications in heat treatment, as well as current practical examples from the field. An FAQ section provides a quick reference to potential sources of error and suitable solutions for every practical scenario.

The 4th edition of the book has been updated to reflect the current state of the art and can be ordered from Vulkan-Verlag .

Transition to the Next Generation

Almost exactly 25 years later, in April 2007, his son Daniel Körtvélyessy took over the company and moved its headquarters to Berlin.