Injection cooled screw compressors do not have a thermodynamical satisfying liquid distribution in the machine. Desired isothermic change of state of the fluid, which would require the smallest power consumption, is not achieved. Today established machines inject the oil into the working spaces nearly exclusively through two injection holes. Here the authors examine different injection variants, in which the oil is injected by nozzles into the suction port of the compressor. The aim of this method is, a finer atomization of the oil jet and therefore an extension of surface of the oil drops to improve heat transfer during simultaneous increase of the contact time between oil and gas.
Oil injected twin-screw compressors are widely used for medium pressure applications in many industries. Low cost air compressors can be adopted for compression of helium and other gases, leading to significant cost saving. The efficiency, delivery rate and the heat of compression of the compressors (medium and small size) has been analyzed and presented in the study. To generate machine independent experimental data, two similar compressors with different capacities have been setup to test the performance of air compressors when applied to compress nitrogen, argon and helium gases apart from air. Also this paper addresses the gas delivery rate and heat of compression (temperature) on volumetric and power efficiency.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.