Hydraulic valve assembly with a pressure compensated directional spool valve and a regeneration shunt valve

A hydraulic circuit for controlling flow of fluid between a first port and a second port of a hydraulic actuator and each of a supply conduit conveying pressurized fluid and a tank return conduit, said hydraulic circuit comprising:

• a spool valve having an inlet connected to the supply conduit, an outlet connected to the tank return conduit, a first workport and a second workport, and having a first position in which fluid flows from the inlet through a metering orifice to the first workport and from the second workport to the outlet, and having a second position in which fluid flows from the inlet through a metering orifice to the second workport and from the first workport to the outlet;
• a pressure compensation valve connected to the spool valve and maintaining a substantially constant pressure drop across the metering orifice;
• a workport blocking valve connecting the first workport to the first port of the hydraulic actuator, and controlling fluid flow there between;
• and
• a regeneration shunt valve connected to the hydraulic actuator and through which fluid flows between the first port and the second port, wherein the regeneration shunt valve has a first state in which fluid flow between the first port and the second port in both directions is blocked and a second state that conveys fluid between the first port and the second port regardless of the state of the workport blocking valve.

A hydraulic circuit for controlling flow of fluid between a hydraulic actuator, that has a first port and a second port, and each of a supply conduit and a tank return conduit, said hydraulic circuit comprising:

• a spool valve having an inlet connected to the supply conduit, an outlet connected to the tank return conduit, a first workport and a second workport, wherein the spool valve selectively directs fluid from the inlet to one of the first and second workports and selectively directs fluid from another of the first and second workports to the outlet;
• a workport blocking valve connected between the first workport to the first port of the hydraulic actuator;
• a regeneration shunt valve connected to the hydraulic actuator and through which fluid flows between the first port and the second port;
• and
• an anti-cavitation valve connected between the first workport and the tank return conduit, and opening in response to cavitation in the hydraulic actuator.