Low Drag D-Ring
In reciprocating applications, drag can be a major factor that drastically reduces the efficiency of the moving piston. Traditional O-rings, when they are not ideally designed, can have a high breakaway friction and are prone to rolling. Bonded piston seals, which are also commonly used as solutions in dynamic applications, are also great at reducing drag, however, they can only seal against pressure from on direction.
Parker’s solution to these issues is the Low-Drag D-Ring. Similar to a common D-ring, the rounded top portion of the cross section provides bi-directional sealing and promotes efficient sliding over mating hardware which the square bottom offers stability and prevents rolling when in motion. Additionally, the relief portion at the bottom provides a lower frictional force on the groove, even when compressed. Functional testing has shown a 30% - 70% reduction in drag when compared to O-rings.