Abstract: A screw-type compressor comprises a housing (12) in which a primary rotor (14) and a secondary rotor (16) are arranged each of which is provided with a shaft (18,24) and a screw rotor (20,26). The secondary rotor (16) is axially supported by the primary rotor (14). Only the primary rotor (14) comprises an axial bearing part (22) which is supported in an axial bearing part (66) of the housing (12). The omission of an axial bearing between the secondary rotor and the housing simplifies the support of the secondary rotor.

Abstract: A compressor system with a water-injection cooled compressor (12) in a cooling water circuit comprises a measuring device (30) in the cooling water circuit (20) to determine the conductivity of the cooling water, a water supply source (40) to supply non-desalinated water and desalinated water, and a controlling means (70). The controlling means (70) causes the introduction of desalinated water and of non-desalinated water. The controlling means (70) causes the introduction of desalinated water, when the conductivity exceeds an upper conductivity limit, and the introduction of non-desalinated water, when the conductivity falls below a lower conductivity limit, from the water supply source (40) into the cooling water circuit (20). Thereby, the pH-value and the salinity of the cooling water are controlled such that corrosion by and deposition in the cooling water are reduced.

Abstract: The invention relates to a compressor installation (10) with an injection-cooled compressor (12) and a method for compressing a gas in a compressor installation. In order to allow for an environmentally acceptable compression of gaseous media, the compressor system (10) is cooled with oil-free cooling water (25) free of additives. The cooling water injection into the compressor (12) is dosed such that the compression is almost isothermal. Further, a water treatment device (31) for preventing mineral deposits is provided that modifies the cooling water (25) such that the formation of mineral deposits in the cooling circuit is prevented.

Abstract: The invention is directed to a method for the production of rotors (10) for screw-type compressors (16) and to rotors (10) to be produced according to said method. To allow the use of a straightforward manufacturing method for the production of rotors (10) of a complex geometry, a method is proposed wherein, during the production of the negative mold, material is removed from a negative mold blank to generate correction regions of a rotor (10).

Abstract: The invention relates to a worn-rive compressor (10) with a main rotor shaft (18) on which are fitted at least one first and one second main rotor (14, 16), each of which meshes with a matching first or second sub-rotor (20, 22) on a rotor layshaft (24). To provide a hard-wearing, economically produced and highly efficient worm-drive compressor (10), the hearings of the rotor main and layshafts (18, 24) are matched to the compressed gas supply in such a way that the loads imposed on the shafts by the pressures produced are absorbed by radially operating bearings (40, 42, 44, 47) near the point at which they arise.

Abstract: The invention relates to a variable-displacement screw-type compressor with at least one main rotor and at least one subsidiary rotor which are fitted in the same housing, mesh together and convey a medium to be compressed from an inlet to an outlet, in which the inlet is bounded by at least one housing segment fitted to slide in the housing which follows the shape of the rotor casings on its sealing side facing the rotors. At least one housing segment is guided and movable transversely to the rotor axes.