Couplings for Pumps and Compressors

Why the Coupling Is Critical in Centrifugal Pumps

In a centrifugal pump, the mechanical seal is one of the components most sensitive to vibration and shaft misalignment. A coupling that does not properly accommodate the misalignment between the motor and the pump transfers that stress directly to the seal, shortening its service life and causing premature leakage. For this reason, flexible jaw couplings or disc couplings are typically preferred in pumping applications, depending on the operating speed of the system.

Selection Based on the Type of Pump or Compressor

Low- and medium-speed centrifugal pumps: Jaw couplings, offering an economical solution with simple maintenance. High-speed pumps and precision equipment: Disc couplings, which require no lubrication and provide better dynamic balance. Reciprocating compressors: Require couplings capable of absorbing the shock loads generated during the compression cycle, typically grid couplings or reinforced jaw couplings. High-demand screw compressors: Higher torque-capacity couplings, selected with the high service factor required for this type of equipment in mind.

Application-Specific Maintenance Recommendation

In pumps and compressors, the coupling should be inspected at the same time as the mechanical seal, since both components affect each other. A leaking seal may be a symptom of a misaligned coupling, not necessarily a failure of the seal itself.