| 摘要 |
<p>1300197 By-passing pigs around pipe-line pump stations HELMERICH-PAYNE Inc 9 June 1971 [25 June 1971] 19739/71 Heading F2N At a pipe-line pumping station, including a pump (not shown) connected by suction and discharge lines 36, 38 to the main pipeline 32, for boosting the pressure at this point in the pipe-line, a by-pass is provided which becomes automatically operative when a pipe-line pig approaches the station to ensure that the pig passes straight through the pipe-line 32, including a section 9 thereof. In the embodiment shown, an approaching pig is sensed at 15 to cause a controller 60 to close a valve. The fluid flow is then past check valve 5, through ports 43 in section 9, and through branch pipes 10 and header 11 to line 36. Valves 3 and 4 are respectively open and closed at this stage. The pig is trapped in section 9, check valve 6 being closed because of the high pump discharge pressure downstream. When the pig passes a sensor 16, valve 1 is reopened and valve 3 closed. Valve 13 is opened to equalize the pressures on opposite sides of valve V and the valves 4 and 2 are respectively opened and closed. The discharge flow from the pump then passes via header 11 and branch 10 to section 9, thus opening check valve 6 and moving the pig downstream. Sensing of the pig at 17 restores the valves to their normal operating conditions. The pig may be used to separate different fluids in which case the control sequence is so timed that the delay imposed upon the pig in section 9 equals time taken for the interface between the two fluids to travel via the pump to section 9. An interlock for preventing simultaneous partial or total opening of valves 3 and 4 may be provided. A single three-way valve at the junction of header 11 and branch 10 may replace valves 3 and 4.</p> |
