The components in the high temperature gas steam ,that is ,the nozzle ring,turbine wheel,blades and rotor shaft are manufactured from heat resisting nickel-chrome alloy steel to withstand continuous operation at temperatures in excess of 450*c. Some degree of cooling may be given by controlled air leak off past the labyrinth seal, between the back of the impeller and volute casing, which flows along the shaft towards the turbine end.
