The bowl in a modern decanter is a cylindrical tube with a flange at either end, on which are bolted at one end the liquid discharge bowl hub. and, on the other end. the cake discharge hub, or the beach followed by the cake discharge hub. The first cylindrical bowls used a filler piece in the end of the bowl to form the beach. On modern bowls, particularly the larger ones, the beach is bolted to a flange at one end of the cylindrical section, although with some overlap to provide mechanical location.
The thickness of the bowl wall is dictated by the material of construction used, the maximum speed at which the bowl will be rotated, and the maximum weight of process material, feed, centrate or cake, likely to be held in the bowl. Thus the density of the process materials in use can have a major effect on the safe working speed of the bowl.
The inside surface of the bowl can be plain machined. However, some effort is often made to encourage cake to stick to the bowl, to aid scrolling instead of slipping round with the conveyor. The means of doing this could be by knurling the inside of the bowl for instance. This can wear smooth relatively quickly. More often longitudinal ribs are welded, or a liner with similar ribs is fitted.
At each end of the bowl the outside bowl diameter can be increased to provide, if necessary, excess metal for removal during balancing. In particular, it can provide a position for machining grooves, which will mate with corresponding baffles in the casing. Together, the grooves and baffles form labyrinths to counteract cross-contamination of the products discharging at either end of the casing.