Patent ID: 7406830
Filing Date: 2008-08-05
Classification: F17C,Y02E

Abstract:
1. A compressor-evaporator system for liquefied gas contained in a tank, the system comprising extraction and pump means for extracting and delivering liquefied gas under low pressure outside the tank, high pressure pump means, evaporator means operating by heat exchange with a liquid, and means for conditioning and transferring gas to a gas pipeline, the system comprising at least one turbomachine constituted by a motor-driven turbopump comprising a rotary assembly having very high bending stiffness on a common shaft line, with at least one high pressure pump comprising an axial suction stage and at least one centrifugal wheel, a turbine, and a central electrical machine capable of being used in motor mode or in generator mode and situated between the high pressure pump and the turbine, said motor-driven turbopump being arranged in compact manner inside a rigid casing that presents static seals only with the surrounding medium, the rotary assembly of the motor-driven turbopump being adapted to present a high speed of rotation, greater than 12,000 rpm, while remaining outside the excitation ranges of critical speeds of rotation, all of the internal portions of the motor-driven turbopump being immersed in a cryogenic fluid that is the same as the liquefied gas contained in the tank, the internal cavities of the motor-driven turbopump that are under different thermodynamic conditions being separated by contactless dynamic seals, and electronic power circuits connected to an electricity network serving to control the central electrical machine in motor mode or generator mode.