Heat recovery systems comprised of pumps and fans, heat exchangers and radiators and valves for gas cycle in Additive Manufacturing Systems, process air systems comprised of ventilating fans for industrial purposes; Valves as parts of heat recovery systems; Installation cabinets and housings for the aforementioned goods; Electric and electronic measuring, signaling, checking, supervision, switch and control apparatus and instruments for the use in or for systems for gas circulation, gas purif...