| 摘要 |
A submersible centrifugal pump for downhole pumping of methane-saturated wat er from wells drilled in coal formations, has an electric motor-driven vertical shaf t having centrifugal impellers distributed therealong, each impeller being located in a stationary diffuser within the pump wall to form a multi-stage pump. A concentric shrou d is located at the lower portion of the pump wall. It is sealed with the pump wall such that all fluid to be pumped must enter holes near the top of the shroud and travel downward through an annulus to the pump inlet. A charge impeller and a solids grinder are locate d at the lower end of the pump central shaft. The multi-stage centrifugal pump is located above the solids grinder and includes multiple compression stages of diminishing volum e as the methane and fluid mixture travels upward through the pump. Another charge impeller may be located at the upper end of the shaft at the outlet pipe. Pressure equalization vents allow fluid flow from the fourth centrifugal stage to the pump-shroud annulu s to maintain pump prime. Centrifugal impellers, each having a hub extending upward and downward along the length of the driving shaft such as to rest upon each other in tur n, while avoiding contact with the stationary diffusers.
|
