| 摘要 |
PURPOSE:To prevent a casing cover and a pump shaft from cracking due to temperature variations, by providing, in the casing cover, a jacket chamber through which fluid in the casing circulates. CONSTITUTION:In a casing cover 4, there is provided a jacket chamber 9 around a pump casing shaft piercing opening 4a. At least one of holes 10 forming the jacket chamber 9 is communicated at its bottom with the inside of a casing 1 through a communicating port 14, and the top of the terminal one of the holes 10 which are indiscretely formed is opened to the gap 13 between the casing cover 4 and a pump shaft 3. Primary coolant at a temperature of about 270 to 280 deg. C which has flowed in the jacket chamber 9 is heat-exchanged with a purging water (a) flowing through the gap 13 between the casing cover 13 and the pump shaft 3.
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