This is the self-priming liquid ring pump, with star-shaped impeller, two directions of rotation as standard, and a high-efficiency motor rated to operate in continuous duty. The special hydraulic shape allows the pump to operate even in the presence of air bubbles in the intake liquid. The liquid ring pump achieves suction by simply filling the pump casing through one of the hose connectors. Suction is active in both directions of rotation. The pump can be used to transfer all kinds of clean, everyday liquids, which must not be chemically aggressive or abrasive. Examples include: water, wine, milk, vinegar, low-viscosity oily solutions, fluid neutral detergents, diesel. The viscosity of the liquid must not exceed 4 cps for continuous duty with free delivery, and must not exceed 20 cps for intermittent duty with free delivery and an operator present for supervision.