| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive and space-saving screw compressor having a surely sealable shaft seal structure on the high pressure side of a rotor shaft. SOLUTION: A first seal member, a second seal member and a third seal member 15, 16 and 17 are arranged in order from the screw rotor 4 side between a screw rotor 4 and a high pressure side bearing 11 of a rotor shaft 7 of the screw rotor 4. This screw fluid machine is provided with a first communicating hole 22 for communicating a first seal space 18 between the first seal member 15 and the second seal member 16 with a space of useful pressure or less of the second seal member 16, a second communicating hole 23 for communicating a second seal space 19 between the second seal member 16 and the third seal member 17 with a space of useful pressure or less of the third seal member 17, and a pressurizing means 24 storing a bearing 11, inserting air into an oil sealing space 20 sealed by the third seal member 17 and pressurizing the oil sealing space 20 to pressure exceeding atmospheric pressure and not more than the useful pressure of the third seal member 17. COPYRIGHT: (C)2010,JPO&INPIT
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