PURPOSE: To provide a water seal for internal pump without leaking of reactor water during maintenance.
CONSTITUTION: A long size hollow pipe shaft 30 is inserted in a casing 3 and the upper end of the hollow pipe shaft 30 is inserted in a plug 31. The plug 31 is attached water-sealed into a diffuser boss 13. The lower end of the hollow pipe shaft 30 penetrates the bottom of the casing 3 and extends from the cylinder 35 provided below the casing 3 to outside. The lower end side of the hollow pipe shaft 30 is water-sealed to the lower part of the cylinder 35 putting an end plug 37 in between. To the hollow pipe shaft 30 inside the cylinder 35, a piston 38 is attached, which is raised by the pressurized water from a pressurized water inlet pipe 39 and lowered by that from a pressurized water outlet pipe 40. A large diameter shaft end 32 is placed at the upper end of the hollow pipe shaft 30, where pure water flows in.
SAKAMAKI KAZUO
WATANABE SHIGERU
ITEL CORP
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