A zoned fluid control system in a valve manifold system has a plurality of manifold blocks connected together and a plurality of control valves mounted to the manifold blocks with the control valves being electrically actuated and pilot pressure operated. The plurality of manifold blocks forms at least first and second separate pilot pressure passages of a respective first zone and second zone not connected to each other for supplying a respective first set and second set of control valves with independently controlled pilot pressure. A pilot supply valve selectively supplies pilot pressure and shuts off pilot pressure to the second pilot pressure passage without affecting the pilot pressure to the first pilot pressure passage thereby disabling the second set of control valves as a separate zone independent from the first set of control valves.

A working machine including a movable implement, a hydraulic actuator for displacing the implement, and a hydraulic control system for enabling an operator to control movement of the implement. The control system allows the implement to be returned to a desired position or state, such as a return to dig position or a return to float state, in a single automated operation that is initiated by the operator actuating a switch at the same time as moving a joystick in a desired direction. A pilot-operated valve is used to supply hydraulic fluid under pressure to the actuator acting on the implement and the operation of the joystick is detected by means of a pressure sensor connected to a control line of the pilot-operated valve.

A zoned fluid control system in a valve manifold system has a plurality of manifold blocks connected together and a plurality of control valves mounted to the manifold blocks with the control valves being electrically actuated and pilot pressure operated. The plurality of manifold blocks forms at least first and second separate pilot pressure passages of a respective first zone and second zone not connected to each other for supplying a respective first set and second set of control valves with independently controlled pilot pressure. A pilot supply valve selectively supplies pilot pressure and shuts off pilot pressure to the second pilot pressure passage without affecting the pilot pressure to the first pilot pressure passage thereby disabling the second set of control valves as a separate zone independent from the first set of control valves.

A hydraulic system includes a hydraulic pump to output an operation fluid, a hydraulic apparatus to be activated by the operation fluid, an operating member to operate the hydraulic apparatus, an operation valve to determine a pressure of the operation fluid in accordance with operation of the operating member, the operation fluid being supplied to the hydraulic apparatus, a first fluid tube connecting the hydraulic pump to the operation valve, a first working valve disposed on the first fluid tube, the first working valve being configured to change an opening aperture of the first working valve, a first outputting fluid tube connected to a section of the first fluid tube between the operation valve and the first working valve, and a second working valve disposed on the first outputting fluid tube, the second working valve being configured to change an opening aperture of the second working valve.

In a closed loop control method for an electropneumatic field device, an electronic target value input of a command variable corresponding to a target value of a control center is received by the open loop and/or closed loop control electronics, an electronic output for a manipulating variable to pilot the electropneumatic converter is generated by the open loop and/or closed loop control electronics; and, in a predetermined operating condition of the field device, the manipulating variable is determined by a closed loop control algorithm based on the command variable and on another controlled variable different from an actual control member position measurement value.

A hydraulic system for a working machine includes a first hydraulic apparatus to be activated by the operation fluid, a second hydraulic apparatus being configured to be activated by the operation fluid, a first operation valve to control the operation fluid to be supplied to the first hydraulic apparatus, a second operation valve to control the operation fluid to be supplied to the second hydraulic apparatus, a first fluid tube connecting the first operation valve to the first hydraulic apparatus, a second fluid tube connecting the first operation valve to the second hydraulic apparatus, a third fluid tube connecting the first fluid tube to the second fluid tube, and an outputting fluid tube connected to any one of the first operation valve and the second operation valve and configured to output the operation fluid supplied from any one of the first fluid tube and the second fluid tube.

A hydraulic system for a work machine includes a hydraulic pump to supply a pilot fluid, and a hydraulic switch valve to be switched to a plurality of switching positions based on a pilot pressure. The pilot pressure is a pressure of the pilot fluid supplied from the hydraulic pump. The hydraulic system includes a direction switch valve to apply a first pilot pressure to the hydraulic switch valve to switch the hydraulic switch valve into one of the plurality of switching positions. The hydraulic system includes a pressure applying device to apply a second pilot pressure to the hydraulic switch valve. The second pilot pressure is lower than the first pilot pressure.

A zoned fluid control system in a valve manifold system has a plurality of manifold blocks connected together and a plurality of control valves mounted to the manifold blocks with the control valves being electrically actuated and pilot pressure operated. The plurality of manifold blocks forms at least first and second separate pilot pressure passages of a respective first zone and second zone not connected to each other for supplying a respective first set and second set of control valves with independently controlled pilot pressure. A pilot supply valve selectively supplies pilot pressure and shuts off pilot pressure to the second pilot pressure passage without affecting the pilot pressure to the first pilot pressure passage thereby disabling the second set of control valves as a separate zone independent from the first set of control valves.

A working machine including a movable implement, a hydraulic actuator for displacing the implement, and a hydraulic control system for enabling an operator to control movement of the implement. The control system allows the implement to be returned to a desired position or state, such as a return to dig position or a return to float state, in a single automated operation that is initiated by the operator actuating a switch at the same time as moving a joystick in a desired direction. A pilot-operated valve is used to supply hydraulic fluid under pressure to the actuator acting on the implement and the operation of the joystick is detected by means of a pressure sensor connected to a control line of the pilot-operated valve.

A hydraulic system for a work machine includes a hydraulic pump to supply a pilot fluid, and a hydraulic switch valve to be switched to a plurality of switching positions based on a pilot pressure. The pilot pressure is a pressure of the pilot fluid supplied from the hydraulic pump. The hydraulic system includes a direction switch valve to apply a first pilot pressure to the hydraulic switch valve to switch the hydraulic switch valve into one of the plurality of switching positions. The hydraulic system includes a pressure applying device to apply a second pilot pressure to the hydraulic switch valve. The second pilot pressure is lower than the first pilot pressure.