Cantilevered pump - a pump whose impeller is cantilevered from its bearing assembly, or a pump with only one bearing housing assembly as opposed to a "between-bearing" pump which has two bearing housing assemblies mounted on opposite sides of the pump casing. A cantilevered pump, which typically is also a radial split pump, can be either a horizontal or a vertical pump. It is also known as overhung pump.
Cartridge seal - A self contained mechanical seal assembly, including the seal, sleeve, gland, mating ring, etc., that is pre-assembled and preset for installation as a unit.
Case - the pressure-containment part of a pump that has the volute (or diffuser) chamber that encloses the impeller, or impellers. The case can be axial or radial split. For radial split case, a cover is required to complete the pump casing.
Case crowning - refers to the method or style of machining the horizontal split-line surface of the upper half case of a horizontal pump with a very small angle, or taper. The purpose of case crowning is to transfer a higher amount of the bolt load towards the case bore to pinch the case gasket and prevent washout especially around the volute areas.
Case retiring thickness - the minimum thickness in which a pump casing has to be replaced, or retired, due to loss of metal thickness caused by erosion or corrosion over a period of time.
Close-coupled pump - a pump whose impeller is mounted directly on the driver shaft. The driver is designed with a special extended shaft to accommodate the impeller. Close-coupled pumps are popular for its small footprint and light weight but are limited in sizes. See flexible-coupled pump.
Closed impeller - an impeller with two shrouds or disks – on front and back side - which enclosed the vanes; also referred to as enclosed impeller.