Potential sinking pumping installation and its control manner null for liquefied gas tank

摘要

PROBLEM TO BE SOLVED: To surely protect a pump rotational system, even when magnetic attraction force of an active thrust magnetic bearing is made controllable. ;SOLUTION: In a submerged pump device for a liquefied gas tank having an active thrust magnetic bearing 61, an auxiliary ball bearing 58 is molted in a position impeding excessive movement of a pump shaft 50 to its perpendicular downward, further a protection device is provided, which has a control function forcedly interrupting a power source of the active thrust magnetic bearing 61 for avoiding excessive movement of the pump shaft 50 to its perpendicular upward in accordance with a displacement value detected by a gap detection sensor 64 detecting a distance δ0 of fine gap part between a balance disk 59 and a stationary part.;COPYRIGHT: (C)1997,JPO