An example valve includes: a sleeve; a first poppet configured to be seated on a first seat defined on an interior surface of the sleeve when the valve is in a closed state, and where the first poppet is configured to move axially within the sleeve; a second poppet disposed, at least partially, in the first poppet, where the second poppet is configured to be seated on a second seat defined on an interior surface of the first poppet, and where the second poppet is configured to move axially within the first poppet; a first spring that interfaces with the second poppet and applies a first force on the second poppet in a distal direction toward the second seat; and a second spring that interfaces with the second poppet and applies a second force on the second poppet in a proximal direction opposite the distal direction.

An example valve includes: a sleeve; a first poppet configured to be seated on a first seat defined on an interior surface of the sleeve when the valve is in a closed state, and where the first poppet is configured to move axially within the sleeve; a second poppet disposed, at least partially, in the first poppet, where the second poppet is configured to be seated on a second seat defined on an interior surface of the first poppet, and where the second poppet is configured to move axially within the first poppet; a first spring that interfaces with the second poppet and applies a first force on the second poppet in a distal direction toward the second seat; and a second spring that interfaces with the second poppet and applies a second force on the second poppet in a proximal direction opposite the distal direction.

The present disclosure relates to a hydraulic circuit, comprising: a motion control valve including a valve spool and a hydraulic actuator for actuating the valve spool, and a hydraulic control device having an outlet fluidically connected to the hydraulic actuator, the hydraulic control device comprising a pressure-reducing valve or a pressure compensated flow control valve.

A construction machine is provided that can cause each hydraulic actuator to accurately operate according to operation by an operator in combined operation in which a hydraulic fluid of a hydraulic pump is subjected to flow dividing and is supplied to plural hydraulic actuators. A controller 10, in a case of determining that combined operation is being carried out, controls a regulator 7a in such a manner that the delivery flow rate of a hydraulic pump 7 becomes larger than the total target flow rate of plural hydraulic actuators 4a, 5a, and 6a, and controls the respective opening amounts of plural directional control valves 8a1, 8a3, and 8a5 in such a manner that the difference between the respective target flow rates of the plural hydraulic actuators and the respective inflow flow rates of the plural hydraulic actuators sensed by velocity sensors 12 to 14 becomes small.

A regulator valve has a check valve manifold for use in subsea control circuits. For example, the regulator valve having the check valve manifold can be used in a circuit between a directional control valve and an actuator for a gate valve. The check valve manifold can be a flange that attaches to the regulator valve to communicate with the supply and outlet of the regulator valve. Internal communication inside the manifold includes a check valve. If the pressure in the circuit downstream of the regulator valve needs to be vented, the check valve can open to allow the pressure to bleed from the outlet back to the supply without needing to pass through the internal pressure control valve of the regulator.

An electromagnetic pressure reducing valve includes a spool valve configured to allow or shut off communication between a pilot passage and a pilot pressure supply passage and a solenoid configured to give a thrust according to an intensity of a supplied electric current to the spool valve. The spool valve has a pressure receiving surface configured to generate a thrust in a direction opposite to the thrust by the solenoid by action of a pressure of a pilot pressure supply passage, and an area of the pressure receiving surface is set smaller than a cross sectional area of the spool valve.

A regulator valve has a check valve manifold for use in subsea control circuits. For example, the regulator valve having the check valve manifold can be used in a circuit between a directional control valve and an actuator for a gate valve. The check valve manifold can have a flange that attaches to the regulator valve to communicate with the supply-side and outlet-side of the regulator valve. Internal communication inside the manifold includes a check valve. If the pressure in the circuit downstream of the regulator valve needs to be vented, the check valve can open to allow the pressure to bleed from the outlet-side back to the supply-side without needing to pass through the internal pressure control valve of the regulator.

The present disclosure provides a pilot proportional control valve apparatus, an automatic calibration method, engineering machinery and a storage medium, and relates to the technical field of engineering machinery, wherein the pilot proportional control valve apparatus including a hydraulic system and a controller; the hydraulic system including: a plurality of proportional pressure reducing valves, a calibration reversing valve, and a pressure sensor; the calibration reversing valve including a plurality of reversing units, an output end of each proportional pressure reducing valve being respectively connected with an input end of one corresponding reversing unit; the pressure sensor being arranged in a detection oil path; the controller performing calibration processing on the proportional pressure reducing valve according to a pilot oil detection pressure and an output pressure value of the proportional pressure reducing valve.

A balancing valve includes four ports. While the pressures at a pair of balancing ports of a hydraulic balancing valve are equal, the valve maintains two other ports in a closed position. Upon a pressure differential between the balancing ports, fluid communication can occur between one of the balancing ports and either of the other ports based upon the direction of the pressure differential. A hydraulic ride control system utilizes the balancing valve together with other control valves to provide ride control functionality.

A main spool (24) has a throttle passage (30) that, when the main spool (24) moves to an axial other side against a first return spring (27) in a main spool insertion hole (13), communicates a pilot pressure chamber (25) with a first tank port (15) and limits a flow amount of hydraulic oil to be discharged to the first tank port (15) from the pilot pressure chamber (25). When the main spool (24) moves to the axial other side along the main spool insertion hole (13), the throttle passage (30) communicates the pilot pressure chamber (25) with the first tank port (15) before a state where a first pump port (17) is communicated with an output port (16) and a state where the output port (16) is blocked from the first tank port (15).