| 摘要 |
PURPOSE:To enable to prevent leakage of liquefied gas at the time of lifting up or installing a submergible pump, by employing a simple arrangement capable of opening and closing a valve under the weight of the valve instead of the spring force. CONSTITUTION:In the state that a pump 3 is lifted up, a cylindrical member 14 adapted for closing the bottom opening of a casing 2 is lowered to the bottom 1a of a reservoir tank by its own weight. In this state, the bottom surface of the casing 2 is sealed by a horizontal seal 17 formed at the lower end of the cylindrical member 14 and a horizontal sealing seat 21 fixed to the bottom 1a of the reservoir tank. At the same time, the cylindrical member 14 and the cylindrical casing 2 are kept in tight contact with each other by a vertical seal 13 and a vertical sealing seat 16. With such a simple arrangement, it is enabled to prevent leakage of liquefied gas at the time of drawing out the pump 3 after replacing the fluid in the pump with nitrogen gas for the purpose of disassembling or repair of the pump 3. |
