| 摘要 |
PURPOSE:To prevent the deterioration of performance by a method wherein the upper end openings of cooling tubes of respective main pump structures are arranged closely without clearances substantially and at least the uppermost stage nozzle among respective steam injection nozzle groups is located above the upper end openings of respective corresponding cooling tubes. CONSTITUTION:The steam injection nozzle group 5 of the principal pump structure 3 is arranged at the axial center of the cooling tube 4 for condensing the vapor of oil while the nozzle 11 at the uppermost stage of respective steam injection nozzle group 5 is located at the upper part than the upper end opening section 4a of the corresponding cooling tube 4. According to this method, an exhausting speed, comparable with single large pump, may be secured and the performance of the pump will never by deteriorated. |
