piston de refoulement plein

OBS: Le piston portant la tête motrice [...] de grande section est un piston plein, il coulisse dans une chambre motrice [...] La face aval du piston portant la tête motrice comporte une protubérance [...] séparée par une distance D de la face amont du piston portant la tête de refoulement [...] qui ferme le réservoir de liquide.

CONT: Nonvented surge blocks are designed to exert a somewhat lesser force on the down-stroke than on the upward stroke or the surging process.
CONT: Surge Blocks.- Device that fits inside a well with a flexible gasket that is close in size to the inside diameter of the well. Attached to a rod that is raised and lowered with a stroke of about 3 feet. Surge block may be solid, vented or spring-loaded