You Choose: Frame Mounted vs. Close Coupled Pumps

There are many factors to consider when deciding whether to use a close coupled pump or a frame mounted pump. This post details the pros and cons of these two mounting styles, to help identify which is best for the application.

Close-Coupled Motor Mounting

Close-coupled pumps use a single shaft that extends from the motor to the pump body through an opening in the cover plate. Typically the impeller is mounted directly to the motor shaft, but in some instances an adapter is utilized. Close-coupled pumps do not need couplings, making this option less expensive than its frame mounted counterpart. They also occupy a smaller footprint and don't need alignment.

Close-coupled pumps are used for applications from simple water service to hazardous chemicals. Exercise caution for applications where there is a seal, however. Process liquid could damage the motor in the event of a seal failure.

With no bearings in this pump design, the motor bearings must handle the axial and radial loads of the application. This limits the size and power of the motor used.

Frame Mounted Pumps

Frame-mounted pumps are mounted next to a motor on a common baseplate, with the pump shaft and the motor shaft connected by a flexible coupling. The design includes a bearing housing to prolong the life of the bearings and allows for continuous operation with high radial and thrust loads.

Frame-mounted pumps are commonly used for larger applications, where power ratings are anywhere from 20HP to 200HP plus.

These pumps are very durable, and less likely to fail due to excessive movement. Therefore, expect a longer lifetime than close-coupled pumps. Frame-mounted pumps don’t need custom motors, giving you more freedom to choose a motor to meet the needs of your application. Mounted pumps are oftentimes the design of choice for continuous service applications.

If you need help selecting the right pump configuration for your application, be sure to talk to an engineer well versed in pumps and pumping systems. 

Not sure which pump to select? Ask us about it! We gladly provide technical assistance to businesses and municipalities in Wisconsin and upper Michigan.