Fluid is delivered by pump 1 into the left end, of cylinder 2. From the right end of this cylinder, fluid is delivered into the left end of cylinder 3, etc. From the right end of the third cylinder (4), fluid is drawn in by pump 1. For the return strokes, fluid is delivered to the right end of cylinder 4 and the process of flow from cylinder to cylinder is repeated in the reverse order. Check valves 5, 6 and 7 operate only during the return strokes.
$4172$CHP,Dr$