Development of the Non-Lubricated Four-Stage Compressor Compressing up to 24

The non-lubricated four-stage compressor which can compress up to 24.52 1\.fPa has been developed This newly developed compressor has high durability and efficiency in comparison with conventional non-lubricated compressors. For the purpose of improving durability, new technologies are adopted in this development. The plunger piston without piston rings is applied at the high pressure stages where the discharge pressure rises more than 4.90 MPa. And the new piston ring being composed of particular anti-wear materials, which are suitable for sliding movement in a nonlubricated condition, is applied at the other stages. Also the new grease, which has a good heat resistance and little scattering property, is selected for the sliding parts of crank mechanism. And then, the use of the original Labyrinth grooves on the plunger piston surface of the high pressure stages keeps a leakage of each stage at a minimum, and the use of the double acting mechanism at the first stage brings about the improvement of volumetric efficiency. Furthermore, the new Scotch Yoke mechanism with built-in springs makes low vibration and small-sized compressor. In this paper, we report the contents of the aforementioned developments in detail