Variable Oil By-pass stroke adjustment allows better valve performance than variable linkage designs. The valve checks have extra time to seat even in heavy liquids since they are idle during the by-pass portion of the suction and discharge strokes.

Variable Oil By-pass stroke adjustment allows better valve performance than variable linkage designs. The valve checks have extra time to seat even in heavy liquids since they are idle during the by-pass portion of the suction and discharge strokes.