The HC3 - D is a variant of the HC3, with all ports in one end. The entire pattern is a miniBOOSTER design. It is a compact unit weighing only 1.75 kg.
The HC3 - D has the pilot-operated dump valve incorporated as a standard feature. Maximum outlet pressure is 800 bar in standard versions. An adjustment of the outlet pressure is carried out by varying the supplied pressure.
The basic operation is illustrated in the function diagram. The oil is fed through the connecting plate to the IN port of the HC3-D flowing freely through check valves KV1, KV2 and DV to the high-pressure side H.
From the high-pressure side H oil is fed to port A on the connecting plate. In this condition maximum flow through the booster is achieved giving a fast-forward function. When pump pressure is reached on the high-pressure side H, valves KV1, KV2 and DV will close. The end pressure will be achieved by the oscillating pump unit OP. The unit will automatically stall when end pressure on the high-pressure side is reached. If a pressure drop on the high-pressure side exists due to consumption or leakage, the OP valve will automatically operate to maintain the end pressure.