Patent ID: 8920575

Claim:
A method of removing foreign matter from a pipeline of a digital hydraulic system, wherein the digital hydraulic system employs a pressure controller comprising a first pressure controller portion and a second pressure controller portion which are connectable to each other, wherein said first pressure controller portion has a first valve array, connected between a supply line and a first output line, and wherein in the first valve array there are a plurality of individually switchable valves that have respective different flow cross-sections, the plurality of individually switchable valves including one of said valves which is largest and which plurality of individually switchable valves are connected in parallel; wherein said first pressure controller portion has a second valve array, connected between a drain line and the first output line and wherein in the second valve array there are a plurality of individually switchable valves that have respective different flow cross-sections, the plurality of individually switchable valves including one of said valves which is largest and which second valve array plurality of individually switchable valves are connected in parallel; and wherein said second pressure controller portion has a first valve array, connected between the supply line and a second output line and wherein in the second pressure controller portion first valve array there are a plurality of individually switchable valves that have respective different flow cross-sections, the plurality of individually switchable valves including one of said valves which is largest and which plurality of individually switchable valves are connected in parallel; wherein said second pressure controller portion has a second valve array, connected between the drain line and the second output line and wherein in the second pressure controller portion second valve array there are a plurality of individually switchable valves that have respective different flow cross-sections, the plurality of individually switchable valves including one of said valves which is largest and which plurality of individually switchable valves are connected in parallel; wherein the method comprises the steps of: connecting the first pressure controller portion to the second pressure controller portion by connecting the first output line to the second output line; opening the valve having the largest flow cross-section in the first valve array of the first pressure controller portion; opening the valve having the largest flow cross-section of the second valve array of the second pressure controller portion so forming an opened flow path from the supply line through the first and second output lines to the drain line; and flushing the opened flow path through the pressure controllers with a pressurized working fluid, while all other valves are closed.