GB1324000A - Pumping station sphere handling method and system - Google Patents

Abstract

1324000 Controlling pipe-line pigs M H GROVE and J M E GROVE [trading as M & J DEVELOPMENT CO] 15 July 1971 [30 July 1970] 33350/71 Heading F2N Product-separating spheres are withdrawn from a pipe-line upstream of a pumping station and stored, and the interface between two fluids is sensed downstream of the pump and used to control launching of spheres from the store back into the pipeline in a desired relationship to the interface. The system shown is for use when three product separating spheres are associated with each interface, the leading sphere being in the interface region and the second and third spheres being located at predetermined spacings behind the leading sphere. The normal fluid flow path through the station is from upstream line portion 10a, via junctions 17, 19, valve 52, pump 11 and valve 33 to downstream line portion 10b. When the leading sphere is detected upstream of the pump station by detector D1, timers T1 and T2 begin an upcount and a controller C2 opens a valve V1 at the top of the sphere magazine 21. When the leading sphere is detected at D2, the upcount in the timers is stopped, the number stored in the timers being representative of the velocity of fluid flow. The leading sphere and subsequently the second and third spheres pass via junctions 17 and 19 to the upper part 21b of the magazine. When the interface is detected by a specific gravity monitor 36, a controller C1 retracts a pin 22, to free the lowermost sphere in the magazine, and opens a valve V3, to inject liquid via line 31 into the magazine to launch the lowermost sphere. Controller C1 also starts the countdown of the number stored in timer T1. The countdown is slower than the upcount by a factor dependent upon the desired spacing between the first sphere (already launched) and the second sphere (which is launched when T1 reaches zero). When T1 reaches zero it also triggers the countdown of T2, this being at a rate dependent upon the desired separation of the second and third spheres. On reaching zero, T2 causes the launching of the third sphere, the closing of valve V1 and the opening of valve V2 to allow the three spheres trapped during this cycle to fall from magazine section 21b to section 21a, ready for launching in the following cycle. A grid 20 in junction 19 prevents spheres from passing to the pump 11. Junction 17 may include a power-operated pivoted gate, Fig. 2 (not shown). An electrical fault in the circuit of the pump 11 may be sensed by a circuit 54, thus causing a controller 53 to open a valve V4, bypassing the pump, and to close valves 52, 33, isolating the pump.