Pump for viscous and abrasive fluids - which has flexibly divided pressure and fluid chambers, which hydraulically drive two double-action pistons rigidly connected within cylinder

摘要

A flexible tube (3) divides a closed casing (1) into two. The outer chamber (4) contains the pressure medium, where the inner chamber (5) contains the fluid to be pumped. The ends of the tube are stiffer than the middle. Two double-action pistons (11), rigidly connected by a stem (12), are driven hydraulically in their cylinder (10,13). Negative pressure in the outer chamber causes the flexible tube to balloon outwards, drawing fluid into the inner chamber via the lower non-return valve (6). Positive pressure compresses the flexible tube to expel the fluid via the upper non-return valve.