Abstract: A rotor structure is provided. The rotor structure includes a plurality of wheels, a main axial tie rod passing through the plurality of wheels and a first shaft and a second shaft each attached to one extremity of the main tie rod, wherein the main tie rod and the bore of an end wheel in contact with one of the first and second shafts delimit a hydraulic chamber configured to receive a hydraulic fluid, and wherein the main tie rod, the hydraulic chamber and the end wheel form an internal hydraulic tension device configured to preload the main tie rod.

Abstract: A rotor structure is provided. The rotor structure includes a plurality of wheels, a main axial tie rod passing through the plurality of wheels and a first shaft and a second shaft each attached to one extremity of the main tie rod, wherein the main tie rod and the bore of an end wheel in contact with one of the first and second shafts delimit a hydraulic chamber configured to receive a hydraulic fluid, and wherein the main tie rod, the hydraulic chamber and the end wheel form an internal hydraulic tension device configured to preload the main tie rod.

Abstract: A gas compression system that includes an electric motor that drives a compressor, a gas treatment device, and a gas cooling device. The electric motor may be cooled by a circulating flow of gas that is cooled by the gas cooling device and had been treated by the gas treatment device. The gas compression system may further include a gas feed that provides a supply of raw gas and a valve connected to the gas feed that controls a flow of raw gas from the gas feed to the gas treatment device. The valve may control the flow of raw gas from the gas feed to the gas treatment device such that any of the circulating flow of gas that is lost due to leakage is replaced. The gas treatment device may remove corrosive or abrasive impurities from the supply of raw gas.