Rotary regenerative heat-exchanger

In a rotary regenerative heat-exchanger operable with cold and hot gas flows which have mutually different variable pressures and velocities, and including a stationary rotor housing having first and second inlets for receiving said cold and hot gas flows respectively and corresponding outlets, a rotor mounted in said housing and containing a regenerative filling mass with gas flow passages therethrough for axial counter flow of said cold and hot gas flows which exert mutually opposed, variable axial forces on said rotor due to flow resistance of said filling mass, and seal means mounted between said housing and rotor for separating said two gas flows therethrough, the improvement in combination therewith comprising at least one control means which is operable in response to said variable pressure of one of said gas flows, and which exerts an axial force on said rotor which force is proportional to the resultant of said forces exerted on said rotor by said gas flows, for maintaining said rotor in a substantially fixed axial position relative to said housing under all conditions of said variable pressure of said gas flows.