| 摘要 |
The method comprises opening a pipeline inlet 3 to permit entry of water at a pressure corresponding generally to the ambient water pressure at one pipeline end 8 and coupling the other pipeline end outlet 5 to a fluid venting system 10,11 in which air is maintained at a pressure sufficiently below the ambient water pressure at the pipeline end 3 to create a pressure differential across the pig to propel it to the end 5. The pig may be propelled along a pipeline 1 when it is filled with water. A buoy 11 receives a hose 10 from the outlet 5 and has a venting outlet in its base with a one-way check valve. The buoy may lie below the water surface. |
