SP Couplings are designed to withstand high pressures and pressure pulses. High pressure pulses create forces that act to separate the male and female couplings.
With couplings that use ball-in-groove retaining mechanisms, the separating forces are concentrated onto a relatively small area – point contact of the balls – which can cause Brinelling (indentation of the balls into the groove), leading to leakage and eventually seizure of the coupling.
Screwed couplings have a screw thread retaining mechanism that distributes the separating forces over a large surface area, thus eliminating brinelling.
