The basic design incorporates a low-pressure piston (LP), a high pressure piston (HP), and a bi-stable reversing valve (BV1). The dump valve (DV) is an optional feature.
Hydraulic fluid at system pressure is supplied to port IN. It flows freely past check valves KV1, KV2 and DV (if included) via port H. At this point, all flow goes through the booster, and a cylinder on the high pressure side, H, will move fast forward. As the cylinder meets resistance, pressure increases in the high pressure side and H is equal to the pump supply pressure. This causes check valves KV1 and DV to close and the oil is directed to Vol. 1. The bi-stable valve (BV1) connects to Vol. 2 to tank via Vol. 3. As pump pressure is applied to Vol.1, the pistons move down.
When the piston has fully moved down, Pilot 1 is energized and operates the bi-stable valve (BV1) to change its position. Fluid is led to Vol. 2, moving the pistons upward and delivering fluid at a higher pressure. The resultant pressure is determined by the ratio in area of the low pressure piston LP to the high pressure piston HP.
Once the high pressure piston has moved up, pilot string 1 is connected to the tank and the bi-stable valve (BV1) returns to its original position and the cycle is repeated until the required end pressure has been established. At that point, the intensifier stops and will only start again to maintain the pressure at the high pressure side of H.
Pressure can be relieved from the high pressure side through the pilot operated check valve DV (if included). By connecting port R to the supply pressure and port IN tank, pilot string 3 will pressurize and allow the fluid from the high pressure side H to flow back to the tank.