Bechtel International Corporation

Thomas C Aude

A method and apparatus for protecting against the abrasion of pipe walls in a slurry pipeline caused by slack flow when the pipeline is operated in the batch mode, i.e., when one or more water batches and one or more slurry batches are transported through a pipeline. Pressure transducers sense the pressure at each relatively high point of the pipeline as an interface between a water batch and a following slurry batch passes that point. When one of the sensed pressures falls below a predetermined low value of pressure, a control device actuates valves to divert the flow downstream in the pipeline through a staged choke containing flow restrictors, thus raising the fluid pressure in the water batch which then counteracts the effect of the static head of the slurry batch. The flow is redirected away from the staged choke when one of the sensed pressures exceeds a predetermined high value of pressure, thus lowering the fluid pressure and preventing pipe wall overpressure.

Apparatus and method for slack flow elimination in a slurry pipeline

One or a plurality of positive displacement slurry pumps are connected to common intake and discharge manifolds at a typical slurry pipeline pumping station. Each pump is connected at its inlet by inlet piping from the intake manifold through an intake isolation valve with a flushing water inlet between the intake isolation valve and the pump. Similarly, each pump is connected at its outlet by outlet piping to the outlet manifold through an outlet isolation valve with a pump drain between the outlet isolation valve and the pump. Conventional pulsation dampeners are connected to the piping at least at the pump outlet and communicate a volume of gas under pressure to the pump for dampening of shock waves. The inlet and outlet piping has a pipe length and slope between the pump on the high side to the station intake manifold and to the discharge manifold on the low side. Settlement of virtually all of the particulate matter of the slurry clear of the intake and discharge isolation valves occurs when the pump is off.

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Orinda, CA, United States of America

Thomas C Aude