The evolution of Enclosure Thermostats
FACILITIES MANAGEMENT THERMAL MANAGEMENT
STEGO
The evolution of Enclosure Thermostats
It is quite fascinating what can be learned from the company founders of STEGO . What did enclosure climatisation look like in the old times ? More than 42 years ago , before STEGO came in to existence , enclosures & panels were heated with a lit light bulb that was , so to speak , in continuous operation . Those were the times before enclosure heaters were available . When the industry finally started using special heaters for enclosures and cabinets , STEGO , too , took part in the business with their first enclosure heaters called „ Heiz-Igel ” ( meaning “ heating hedgehog ” from the look of the heater ). These heaters were not regulated , thus ran in continuous operation , as there were no enclosure thermostats at that time either . This has proven to be a significant disadvantage , as there is no upper temperature limit in a panel if the heater runs non-stop : permanently high temperatures limit the service life of other devices installed in the cabinet .
Some enclosure manufacturers started using household or room thermostats at some point , due to the lack of adequate equipment . However , these were able to measure and control temperatures up to 25 ° C only . This was the time when the idea of an enclosure thermostat by Hartmut Eisenhauer came into play . The first controller was a so-called “ change-
STEGO Temperature Regulator FZ 170 Series in an
aluminium housing STEGO Small Thermostats KTO 111 ( red ) and KTS 111 ( blue ) w / Push-In connection
terminal
over ” contact and located in a metal housing .
Together with the manufacturer of the bimetal regulator , Hartmut Eisenhauer advanced a bimetal sensor used for temperatures above 120 ° C to the temperature range relevant for use in enclosures and cabinets . It was then possible to heat up an enclosure to a desired temperature , and when the desired temperature was reached , to stop the heater and to start a fan or filter fan ventilating or cooling the space .
However , Eisenhauer was not yet satisfied with this solution . He divided the “ changeover ” contact into two separate contacts – a “ normally closed ” contact and a “ normally open ” contact and put them in two separate housings . Now it was possible to activate a heater for low temperatures , and to stop the heater when the desired temperature was reached . And then , only if necessary , to switch-on a fan or filter fan using the “ normally open ” contact that was set to a maximum temperature . This was STEGO ’ s first product launch of the mechanical small thermostats for enclosure climatisation on the market – back then they were called KTO 1140 and KTS 1140 , see photo 2 .
Does this mean that everyone else has just copied STEGO ’ s small enclosure thermostats ? Let ’ s just leave this question at that …
STEGO are still selling re-designs of the original „ change-over “ thermostat in large numbers , and have continuously improved the small thermostats with „ normally closed “ and „ normally open “ contacts , resulting in a major re-design , new thermostats KTO 111 and KTS 111 , see photo 3 , with Push-in terminals for tool-free connection – the Re-Design of our classics KTO / KTS 011 .
Additionally , STEGO complemented the product range with other types of regulators , such as hygrostats , hygrotherms ( a combination of a hygrostat and a thermostat ) and electronic regulators . Experts at STEGO are happy to help you to choose the right thermostat for your enclosure application .
The full range can be found here at https :// en . stego . de / products / regulating
48 PECM Issue 63