Termisk isoleringsanordning och isoleringselement för axeln av en termovals

摘要

PURPOSE: To provide an excellent heat insulating capacity that displays the least sensitive reaction to stress applied thereto by operating environments by interposing a wall portion between another wall portion and a shaft periphery in sealed fashion so that it defines together with the second wall portion a cavity enclosing a longitudinal channel. CONSTITUTION: A heat insulating element 10 enclosing an oil feed channel 6 and an oil return channel 7 comprises an inner cylindrical bushing 11 functioning as the outer wall of the heating oil return channel 7 and an outer bushing 12 delimiting, together with an end member of the element 10, a cavity. The end member is joined to one end of the bushings 11 and 12 via electron beam welding within a vacuum chamber. The sealed cavity of the heat insulating element 10 maintains the same vacuum state as the vacuum chamber of the welding equipment in operation creates typically in the order of 10 Pa or 1×10<-4> bar. The vacuum cavity has an excellent heat insulating capacity.