| 摘要 |
PROBLEM TO BE SOLVED: To provide technology for always normally operating a long screw shaft, possibly causing severe heat generation, independently of the length and rotating speed thereof, and cooling it in a long-time stable manner. SOLUTION: This rotary joint for collecting a cooling water W supplied to a corner end 10 of a long flow passage 9 in a screw shaft 6 comprises a long insert pipe 4 having an outer diameter smaller than the diameters of holes in seal rings 21, 22 and the inner diameter of the flow passage 9 in the screw shaft 6, inserted from a sealing hole to the corner end 10 of the screw shaft flow passage, in the state of being inserted through the seal rings 21, 22. The long insert pipe 4 is supported rotatably following the screw shaft 6, with the rear end communicating with a second external connection port 13 opened in a casing 1. A second sealing portion 5 is arranged between a first external connection port 12 communicated with the screw shaft flow passage 9 and the second connection port 13.
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