A servo valve is provided with a first elastic portion, a second elastic portion, and a connecting portion. The first elastic portion extends in an X direction inside a valve body and has a first elastic force exerted on a movable element toward an X2 direction. The second elastic portion extends in the X direction inside the valve body and has a second elastic force exerted on the movable element toward an X1 direction. The connecting portion is connected to the first elastic portion and the second elastic portion inside the valve body, and is in abutment against a step portion of the valve body and a spool of the movable element at a neutral position of the movable element.

A multi-way poppet valve and methods for using the same are provided. In one embodiment, the poppet valve includes a manifold and a poppet assembly including an inner poppet and an outer poppet defining one or more lands. The poppet assembly can dimensioned for receipt within a bore of the manifold and configured to move longitudinally within the manifold. The inner poppet and the outer poppet can also be formed in two separate pieces that are capable of moving with respect to one another. This design can allow the lands of the poppet assembly to form fluid-tight seals (e.g., metal-metal, metal-gasket, etc.) with the manifold. In this manner, the poppet valve can move longitudinally between open and closed positions where the fluid-tight seals respectively allow or inhibit fluid flow between selected ports of the valve.

Embodiments of the present disclosure describe both mechanically-operated and electrically-operated, locally-actuated partial stroke testing devices and systems for testing operation of an emergency isolation valve.

This disclosure includes systems and methods for actuating hydraulically-actuated devices.

An apparatus for determining a movement direction of a component of a mechanism. The apparatus includes an acoustic emission sensor arranged to detect acoustic emission from the mechanism, and a processor arranged to determine a Doppler shift in a frequency characteristic of the measured acoustic emission and to determine a movement direction of a component of the mechanism on the basis of the determined Doppler shift. A method of determining a movement direction of a component of a mechanism including detecting acoustic emission from the mechanism and determining a Doppler shift in a frequency characteristic of the measured acoustic emission and, determining, based on the Doppler shift in the frequency characteristic, a movement direction of the component of the mechanism.

The present disclosure relates to a double-juxtaposed-valve-core rotary multi-functional hydraulic regulating valve driven by two motors. The hydraulic regulating valve includes a first regulating component, a second regulating component and a valve block. The first regulating component includes a first motor, a first valve core, a first connection sleeve and a first valve sleeve. The second regulating component includes a second motor, a second valve core, a second connection sleeve and a second valve sleeve. The first motor and the second motor are provided with angular displacement sensors. Both the first valve core and the second valve core include a connection portion and a cylinder portion. The cylinder portion defines a group of crossed radial through holes. Both the first valve sleeve and the second valve sleeve are of hollow cylinder structures.

The present disclosure relates to a valve assembly including a valve moveable between an open position where hydraulic fluid flow is permitted between first and second ports of the valve and a closed position where hydraulic fluid flow is blocked between the first and second ports. A characteristic vibration is generated by turbulent hydraulic fluid flow within the valve when hydraulic fluid flow is first initiated between the first and second ports as the valve moves from the closed position toward the open position. The valve assembly also includes a controller for providing electrical current to control movement of the valve via a solenoid. The controller includes an accelerometer for sensing the characteristic vibration. The controller identifies an electrical current value of the electrical current at a time when the characteristic vibration is detected.

A hydraulic fluid cylinder is equipped with a cylinder tube, a piston unit, and a piston rod. The piston unit has a piston body provided with a gasket-mounting groove. A gasket member is mounted in the gasket mounting groove. The gasket member has a gasket body provided with a magnet-mounting groove exhibiting groove depth in the axial direction of the piston unit, and also has a magnet mounted in the magnet-mounting groove.

The present invention discloses a load-sensing multi-way valve with a variable differential pressure, where each valve group uses a new element: an electro-hydraulic pressure compensation valve, so as to implement continuous real-time adjustment and control of compensated differential pressure and real-time position feedback and monitoring of a compensation valve trim, and overcome a flow mismatch problem of a conventional LS system in a flow saturation working condition and problems of a fixed shunting proportion of an LUDV system and poor operation coordination of actuators. The load-sensing multi-way valve with a variable differential pressure disclosed in the present invention has advantages such as strong working condition applicability, high flow distribution accuracy, and strong technicality.

The present invention provides an engineering machinery hydraulic system with compensation differential pressure controllable, uses an electronic pressure compensating valve to solve the problem of flow mismatch under conditions of pressure over-limit and flow saturation, and realizes proportional shunt control and high-precision flow distribution of the system. The engineering machinery hydraulic system disclosed in the present invention has the advantages of low energy consumption, fast response speed, and high flow control precision.