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 assistant at Degussa. In 1974 he took on a leading position 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 the thermoelectric principle, which redefines the creation of thermoelectric voltage. In short, most of the voltage is created at the highest temperature gradient.

The second principle is derived from the above model. It deals with the drift of the thermocouples, which had previously been a significant problem in heat treatment.

Through experiments and calculations, Dr. Körtvélyessy changed the diameter of the two thermocouples. The aging is still present, but now both wires age at the same rate, so that the correct thermoelectric voltage is always generated.

The third principle is the introduction of very thin and separate ceramic protection tubes in a connection head, in contrast to the thick ceramic protection tubes that were common then and are common today, as well as the introduction of an empty tube, which is fitted with a test thermocouple for control purposes.

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

The company logo was also derived from this model:

Schema of the cross section of a double thermocouple with additional test tube
Schema of the cross-section of a double thermocouple with additional test tube
Logo of the thermo-control Körtvélyessy GmbH
Logo of thermo-control Körtvélyessy GmbH with the rotated Y as a connector.

The technological leap is the very high resistance to thermal shocks and the even more important fast response time, due to better heat transfer, which the thin wall thicknesses enable.

In addition to these three main principles, improvements have been made to the models to build thermocouples that are as long-lasting and reliable as possible. Thermo-control is still the only provider with a 4-year warranty and a fleet of thermocouples that are on average older than 10 years and 99.8% break due to external mechanical influences.

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

Oxygen probes are based on Nernst's law, which states that a density gradient separated by an electrolyte causes a voltage. This physical law applies to all oxygen probes, but it is up to the design of the probe to keep the conditions constant. Analogous to thermocouples, Dr. Körtvélyessy also introduced technical innovations here, which made the thermo-control oxygen probe an outstanding product. The reaction time, reliability, and robustness of the thermo-control oxygen probes are currently unrivaled.

A further development brought the world's only available vacuum-tight oxygen probe onto the market. This is particularly ideal for low-pressure carburizing furnaces.

Visualization of the flow at the probe to avoid clogging by particles
Visualization of the flow at the probe to avoid clogging by particles
Connection head with G3/4 inch process thread of an oxygen probe
thermo-control oxygen probe

Thermoelement Praxis

Dr. Körtvélyessy summarized his extensive experience in practical temperature measurement in his book “Thermoelement Praxis”. The book has become a reference work for all practitioners in temperature measurement.

The state of the art in temperature measurement and heat treatment is presented clearly and, as usual, in a practical way using the tried and tested triple thermocouple. New additions are type N thermocouples and their possibilities for use in heat treatment, as well as current practical examples from the application area. With an FAQ overview area, a reference to possible sources of error and suitable solutions can be found quickly for every practical case.

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

Thermoelement Praxis ISBN-9783802729775
Thermoelement Praxis

Transition to the next generation

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

Managing Director Dipl.Ing (FH) Daniel Körtvélyessy