OIL-FREE SCREW COMPRESSOR

摘要

Provided is an oil-free screw compressor having a shaft sealing device with good assembly properties and enabling the leakage of compressed gas from the shaft sealing device to be reduced. In the oil-free screw compressor (1): a pair of male and female screw rotors (16) that fit together are housed in a rotor chamber (15) of a compressor casing (12); the screw rotors are supported by a bearing (22) via a rotor shaft (21); and a shaft sealing device (30, 40) that seals the rotor shaft and is arranged in a shaft sealing space (10), which is in the casing and formed between the rotor chamber and the bearing, is included. The shaft sealing device is equipped with an oil seal (31) positioned to the bearing side, a packing case (41) positioned to the rotor chamber side, and a gas seal (42) for sealing gas. A sealing ring is housed in a gas seal housing space (48) that is formed when an end (44) of the bearing side of the packing case and an end (33) of the rotor chamber side of the oil seal are fitted and fixed together by interference fitting.