Escaped from the communist regime in Hungary in 1971, he got a position as scientific research engineer at Degussa /Hanau. 1974 he took a position as senior designer at Ipsen International Kleve.
In more than 30 granted patents and countless publications three principles changed the world of modern temperature measurement.
The first principle is the definition of the thermoelectric principal, which defines the generation of the thermoelectric voltage in a very simple model. This model and many other FAQ's are compiled in his book "Thermoelement Praxis".
The second principle is a result of the first one, as it addresses the drift of thermocouples which was until that time a huge issue in the industry.
Drift is a result of different aging of the thermowires as they have to be made of different materials in order to work as a thermocouple.
Since aging cannot be influenced without changing materials, Dr. Körtvélyessy changed the diameter of the wires. By doing so he "adjusted" the aging speed of the wires. Therefore both wires will age the same, hence the difference, the thermovoltage, will not change, even after several years.
The third principle was the introduction of using separate thin wall thickness tubes for each thermocouple with an additional empty tube, instead of big ceramic tube with several cavities (what is still used by many other manufactures)
The company's logo is a result of this philosophy. Below two tubes with thermocouples and above them an empty tube:
This change in design philosophy has many advantages. One is the improved durability against thermal shocks. The other is that the two measuring thermocouples will not be cooled down during a calibration measurement, which would lead to an increased heating of the furnace, risking damaging the parts.
Next to the above mentioned principles Dr. Körtvélyessy constantly improved the design to achieve a reliable thermoelement with very long life time. Still thermo-control is the only manufacture of thermoelements with a warranty of 4 years and a fleet age of approx. 8-9 years.
In 1987 Dr. Körtvélyessy introduced a new oxygen probe as his second product line.
The function of an oxygen probe is based on the law of Nernst which defines a voltage between two different densities. This physical law determines the life of all probes. However it is up to a effective design to reduce other influences. More....
Dr. Körtvélyessy managed to increase the reliability and lifetime introducing many technical innovations. Still thermo-control is the only manufacturer who warrants a lifetime of up to 4 years. Especially the design of a vacuum proof oxygen probe predestines it for the control of low-pressure carbonization processes.
After 25 years his son Dipl.-Ing.(FH) Daniel Körtvélyessy took over the business in manufacturing and development of thermoelements and oxygen probes. In April 2007 he moved thermo-control facility to Berlin, continuing the tradition of manufacturing high-end products, such as thermoelements and oxygen probes, and developing new applications.