Solid and Split Casings Pumps
Solid casing implies a design in which the discharge waterways leading to the discharge nozzle are all contained in one casting or fabricated piece. The casing must have one side open so that the impeller can be introduced into it. Because the sidewalls surrounding the impeller are actually part of the casing, a solid casing, strictly speaking, cannot be used, and designs normally called solid casing are really radially split.
A split casing is made of two or more parts fastened together. The term horizontally split had regularly been used to describe pumps with a casing divided by a horizontal plane through the shaft centerline or axis (see Figure 10). The term axially split is now preferred. Because both the suction and discharge nozzles are usually in the same half of the casing, the other half may be removed for inspection of the interior without disturbing the bearings or the piping. Like its counterpart horizontally split, the term vertically split is poor terminology. It refers to a casing split in a plane perpendicular to the axis of rotation. The term radially split is now preferred.