Abstract: The present disclosure relates to a refrigeration system for cooling the interior of a mobile refrigerated space, for example a refrigerated container, comprising two speed-controlled compressors, which can be operated in parallel as a single stage or one after the other as two stages by one controllable bypass line per compressor and a controllable valve device between the pressure side and the suction side of each compressor. The valve devices receive signals from a controller having algorithms, into which the usage temperature and ambient temperature are fed as a target value or measured value. The most energy-efficient operating modes and the rotational speeds of the compressors result from the requirements profile of the container refrigeration.

Abstract: A screw compressor (10) with at least one screw rotor (20, 22) which is rotatably arranged about a rotational axis arranged in the axial direction. The at least one screw rotor (20, 22) is arranged in a compression area (24) which is fluid-tight against the surrounding area at least in some sections and opens into a high-pressure volume (26). The compressor (10) further has a Vi slide (28) for influencing an inner volume ratio of the compressor, the Vi slide (28) at least partly forming a section of the fluid-tight border of the compression area (24) and being arranged such that the position of the slide can be adjusted in the axial direction. The Vi slide (28) can be continuously displaced, and the compressor (10) has a device (32) for detecting the position of the slide.

Abstract: The invention present disclosure relates to a refrigeration system for cooling the interior of a mobile refrigerated space, for example a refrigerated container, comprising two speed-controlled compressors, which can be operated in parallel as a single stage or one after the other as two stages by means of one controllable bypass line per compressor and a controllable valve device between the pressure side and the suction side of each compressor. The valve devices receive signals from a controller having algorithms, into which the usage temperature and ambient temperature are fed as a target value or measured value. The most energy-efficient operating modes and the rotational speeds of the compressors result from the requirements profile of the container refrigeration.

Abstract: In screw compressors for extremely high discharge pressures, the geometrical centers of all coaxial holes or housing bores are all located in one single housing section on the male rotor side at a certain first straight line and the geometrical centers of all coaxial holes or housing bores are all located in one single housing section on the female rotor side at a certain second straight line. The diameter of all coaxial holes in the housing on the male rotor side, and the diameters of all coaxial holes in the housing on the female rotor side, decrease from the open to the closed end of the housing section. Based on this construction, the bearings and the components adjacent to the bearings are guided at their periphery in one single housing section so that there will be no coaxial deviations caused by assembly and no coaxial deviations in long term operation.

Abstract: On screw compressors for extremely high discharge pressures, e.g. for application in refrigeration systems operating with CO2 in a transcritical process, featuring two rotors, a male rotor and a female rotor having a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7, with the male rotor having a drive-shaft end, and both rotors are enclosed in a housing, the wrap angle of the profile section of the male rotor is less than 1.5 the lobe-pitch angle, and the working cycle from the beginning of suction till the end of discharge is less than 600° of the angle of rotation of the male rotor, and the length-to-diameter ratio of the profile section of the male rotor lies between 0.3 and 0.5.

Abstract: The invention relates to oil-flooded screw compressors having a male rotor and female rotor each featuring preferably a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7. In order to decrease the bearing load at higher working pressures, the profile sections of the rotors are shortened, and an intermediate plate is appropriately arranged in the free space formed.

Abstract: Screw compressor having male- and female rotors for extremely high discharge pressures, the radial bearings and the supporting flanges enclosing the radial bearings tight-fitting adjoin the housing bores with their centres arranged on two parallel axes of the housing.

Abstract: A refrigeration apparatus for transcritical operation includes a gas cooler, an aftercooler, an evaporator with a low-pressure liquid separator, a compressor, a first controllable throttling device and interconnecting piping between the mentioned components and in addition a second controllable throttling device and an intercooler that comprises two flow paths separated by heat exchanging surfaces. A first flow path inlet of the intercooler is connected to the gas cooler outlet. A first flow path outlet of the intercooler is connected to the aftercooler inlet. A second flow path inlet of the intercooler is connected to the outlet of the second throttling device. A second flow path outlet of the intercooler is connected to the economizer port of the compressor. The second throttling device inlet is connected to the piping either upstream or downstream of the aftercooler. The second throttling device outlet is connected to the second flow path inlet of the intercooler.

Abstract: In an arrangement on an oil-flooded screw compressor with two rotors, a male rotor having essentially convex lobe flanks and a female rotor having essentially concave flank portions, with the male rotor having a drive-shaft end and an oil-pressure loaded balancing piston supplied with oil via a pressure line, both rotors are enclosed in housing sections, with a regulating device arranged either on or in the compressor the inputs of which are at least connected to measuring means for the pressure on the suction side and measuring means for determination of the input power, wherein according to the invention means for changing the pressure in the pressure line to the balancing piston are arranged with said means having a control interconnection to the regulating device, with the latter having an algorithm between operating parameters representing input variables for the regulating device and the pressure in the pressure line to the balancing piston.

Abstract: On screw compressors for extremely high discharge pressures, e.g. for application in refrigeration systems operating with CO2 in a transcritical process, featuring two rotors, a male rotor and a female rotor having a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7, with the male rotor having a drive-shaft end, and both rotors are enclosed in a housing, the wrap angle of the profile section of the male rotor is less than 1.5 the lobe-pitch angle, and the working cycle from the beginning of suction till the end of discharge is less than 600° of the angle of rotation of the male rotor, and the length-to-diameter ratio of the profile section of the male rotor lies between 0.3 and 0.5.

Abstract: The invention relates to oil-flooded screw compressors having a male rotor and female rotor each featuring preferably a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7. In order to decrease the bearing load at higher working pressures, the profile sections of the rotors are shortened, and an intermediate plate is appropriately arranged in the free space formed.

Abstract: The invention relates to a cascade refrigeration system with screw compressors (3) connected with each other thermally via a heat exchanger (20) wherein the refrigerant of the low-temperature circuit is condensed in said heat exchanger (20), and the refrigerant of the high-temperature circuit is expanded in said heat exchanger (20), and in addition to said heat exchanger (20) a desuperheater (8) is arranged in flow direction ahead of said heat exchanger (20) in which the working medium of the low-temperature side is cooled down, while the working medium of the high temperature circuit is expanded.

Abstract: The invention relates to a cascade refrigeration system with screw compressors (3) connected with each other thermally via a heat exchanger (20) wherein the refrigerant of the low-temperature circuit is condensed in said heat exchanger (20), and the refrigerant of the high-temperature circuit is expanded in said heat exchanger (20), and in addition to said heat exchanger (20) a desuperheater (8) is arranged in flow direction ahead of said heat exchanger (20) in which the working medium of the low-temperature side is cooled down, while the working medium of the high-temperature circuit is expanded.

Abstract: A rotor pair for a high-pressure screw compressor having main and secondary rotors, the main rotor having essentially convex teeth arranged outside its reference circle and the secondary rotor having essentially concave teeth arranged inside its reference circle. The distance between the axes of the rotors, which limits the size of the possible bearings, is enlarged only by increasing the number of teeth and the diameter of the secondary rotor so that it is larger than the main rotor.