| 摘要 |
PROBLEM TO BE SOLVED: To simplify the structure of a shaft seal device for an oil-free screw compressor. SOLUTION: The oil-free screw compressor 1 compresses suction air by meshed rotation of a pair of male and female screw rotors 3, 4. In the compressor 1, bearings 8, 10 supporting rotor shafts 5, 5a on the suction side and the discharge side of the respective screw rotors 3, 4 are provided on the rotors 5, 5a, while the shaft seal devices 11, 12 sealing an action space 15 from bearing boxes 7, 9 housing the bearings 8, 10 are provided between the bearings 8, 10 and the screw rotors 3, 4. The shaft seal devices 11, 12 are respectively formed with gaps 14 enclosing the rotor shaft 5, and a communication passage 17 communicating the gap 14 formed in the suction-side shaft seal device 11 with the gap 14b formed in the discharge-side shaft seal device 12 is formed between the gaps 14, 14b.
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