| 摘要 |
<p>An electrical downhole centrifugal pump for pumping fluids from a deep well includes a relatively small diameter pump housing which is suspended from a tubing string and including a series of impellers and diffusers. The impellers are mounted on a vertical shaft (32) connected to a motor for driving the impellers relative to the diffusers on the housing. Upper and lower shrouds (42, 44) enclose the top and bottom surfaces of impeller blades (46) rotating with the shaft. A first group of impellers are arranged to move freely longitudinally on the shaft while a second group are fixed to the shaft to prevent relative longitudinal motion. A lifting vane (68) is formed on the outer surface of the upper shroud on the impellers which are fixed to the shaft. A net lifting force is thus applied to the shaft by those impellers of the second group having upthrust impellers to diminish the load carried by a pump shaft thrust bearing.</p> |
