The RD-400 is a constant volume priority divider. It can be used in applications where two circuits are to be supplied by a single pump such as power steering sytems. In operation the flow of oil supplied to the inlet is divided into two flows, the priority flow and the excess flow. The priority flow will remain nearly constant with variations in pressure on either the priority or excess flow port and will also remain nearly constant with variations in the inlet flow. The RD-400R provides the same function as described above with the addition of a built-in pressure relief for the priority port only. This relief is factory set at 1500 psi.