Abstract: The invention relates to a method for a refrigerant system having a circulation circuit comprising a screw compressor (1), a condenser (4), an expansion valve (5) and an evaporator (6). In a refrigerant process, in which an oil injected compressor is connected it is impossible to prevent oil from flowing together with the refrigerant out into the circulation circuit, which among others impairs the operation of the evaporator. According to the invention a drastic reduction of the amount of circulating oil has been obtained together with an improved cooling of the compressor by supplying the low pressure side of the compressor with refrigerant liquid with a pressure and temperature lower than the pressure and temperature of the refrigerant in the condenser in such amounts per unit of time that the required cooling and sealing of the compressor is obtained, the effect of the circulating oil being restricted merely to lubricating.

Abstract: A screw compressor lubrication channel for lubrication of a rotor bearing on the compressor's low pressure side, which is supplied with refrigerant droplets containing oil accompanying the inlet gas. This kind of lubrication is usually carried out by permitting a limited amount of gas and oil to flow from the high pressure side to the low pressure side via the bearings located on the low pressure side, and further to the inlet. By this working mode compressor capacity as well as compression work deposited is lost. This is avoided when the compressor according to the present invention is provided with a special, smaller inlet channel (7), which via the rotor bearing (3) opens out in a specific inlet port (8) located at an expanding rotor thread presenting a lower pressure than the inlet (6) pressure of the compressor.

Abstract: A rotary internal combustion engine comprising two intermeshing rotors provided with radially extending lobes and intervening grooves, the lobes of at least one of the rotors being provided with radially extending channels for supply and return of cooling liquid from and to, respectively, axially extending central channels of the rotor, said return channels being interposed between said supply channels and a heated surface portion of the lobes. The temperature difference between the cooling liquid portions in the radially extending channels being utilized for circulating the liquid under the action of the centrifugal forces arising during rotation of the rotors.

Abstract: A rotary internal combustion engine of the type comprising a power rotor provided with a number of axially extending lands, an abutment rotor intermeshing with said power rotor and provided with a higher number of axially extending grooves than that of the lands of the power rotor, and a casing carrying and sealingly enclosing said intermeshing power rotor and abutment rotor and forming together with the flanks of said rotors moving chambers containing air with different pressures. A carburetor or similar type of fuel injecting means is provided in a channel forming a communication between a first chamber where the air has been partly compressed and a second chamber in which the air is at least substantially uncompressed.