Two limit switches are installed on the frame to control the reversal valve to change the movement direction of the rubber knife, at the same time it protects the cover of the cylinder.

The in-line spring-actuated lift check also is referred to as the "silent check" because the spring closes the valve before gravity and fluid reversal can slam the valve closed.

Swing-type check off er the least pressure drop and offer simple automatic closure; when fluid flow stops gravity and flow reversal closes valve.