Close-coupled pumps are characterised by a common motor and pump shaft or by their motor shaft and pump shaft being rigidly connected in a pump casing. The pump casing is bolted to the drive flange rather than being installed on pump feet. This enables straightforward installation as the shafts and casings do not need to be aligned. See Fig. 1 Close-coupled pump
Close-coupled pumps are limited to relatively small pump power outputs as the forces and moments in the pipelines (see Pump nozzle load) have to be absorbed by a motor housing with integrally cast or bolted-on feet (supporting angles).
An alternative to the close-coupled pump is the closely-related flanged motor pump, which is installed on pump feet rather than motor feet. A flanged motor pump can absorb larger pipeline forces and moments. As a result, it is able to transfer larger amounts of power than a close-coupled pump.