Barrel type centrifugal pump - has volute built into outlet duct to increase delivery pressure

A barrel type centrifugal pump or open pit pump is housed in a cylinder (1) installed below the water level. Water flows in through the inlet (6), across the impeller (4) and up the central pipe (3). A volute casing (5) is attached to the upper end of the central pipe (3) and deflects the water to the outlet (7). Using a volute instead of the usual T junction increases the delivery pressure of the pump. The principle can be equally well applied to a pump with a double sided impeller. In addition the delivery pressure may be still further increased by installing a second impeller in the mouth of the volute casing. L'invention concerne les pompes centrifuges, notamment en cuve. Elle consiste à former la tête de colonne de la pompe par une volute de refoulement fixée sur l'extrémité supérieure de la cuve et du tuyau de transmission. Elle est applicable aux pompes en cuve (du type dit à barrel) et aux pompes de forage.