Example aspects of an over-pressure protection system and a method for using an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body comprising a main body housing, the main body housing defining a main body chamber; an incompressible fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor for measuring the fluid pressure of the incompressible fluid, the pressure sensor configurable an activated mode and a deactivated mode; a first barrier movable between a first position and a second position; wherein the over-pressure protection system is configurable an under-pressure configuration, wherein the pressure of the incompressible fluid is below a threshold pressure, and an over-pressure configuration, wherein the pressure of the incompressible fluid is equal to or above the threshold pressure; and a control system configuring the pressure sensor in the deactivated mode in the over-pressure configuration

In a hydraulic drive system for an electrically driven hydraulic work machine that executes flow rate control of a hydraulic pump by controlling a rotation speed of an electric motor to drive a hydraulic pump to supply a hydraulic fluid to a plurality of actuators, and power consumed by the electric motor reliably limited within a range of preset maximum allowable power without unnecessary degradation of responsiveness of the electric motor. To this end, a controller includes a maximum angular acceleration limitation section (allowable rate computation section and rate limitation section), computes hydraulic power consumed by a main pump, computes a maximum angular acceleration allowed for an electric motor on the basis of a magnitude of the hydraulic power and a preset maximum allowable power consumable by the electric motor, and limits an angular acceleration of the electric motor not to exceed the maximum angular acceleration.

The present invention relates to a hydraulic valve control unit for an open center hydraulic system, the open center hydraulic system comprising a pump, a shunt valve and one or more actuator valves coupled to the shunt valve, wherein each actuator valve is controlling a corresponding actuator's position, the hydraulic valve control unit comprising a processor and a memory, said memory containing instructions executable by said processor, wherein said hydraulic valve control unit is configured to obtain user input data indicative of at least a desired actuator's position, determining opening area values of the one or more actuator valves using a predetermined relation dependent on the user input data, determining an opening area value of the shunt valve using the predetermined relation dependent on the user input data, controlling the shunt valve based on the opening area value of the shunt valve, and controlling the one or more actuator valves based on the opening area values of the one or more actuator valves. The invention further relates to an open center hydraulic system.

Example aspects of an over-pressure protection system and a method for using an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body comprising a main body housing, the main body housing defining a main body chamber; an incompressible fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor for measuring the fluid pressure of the incompressible fluid, the pressure sensor configurable an activated mode and a deactivated mode; a first barrier movable between a first position and a second position; wherein the over-pressure protection system is configurable an under-pressure configuration, wherein the pressure of the incompressible fluid is below a threshold pressure, and an over-pressure configuration, wherein the pressure of the incompressible fluid is equal to or above the threshold pressure; and a control system configuring the pressure sensor in the deactivated mode in the over-pressure configuration

A remote controlled demolition robot (10) comprising a controller (17) and at least one actuator (12) controlled through a hydraulic system (400) comprising at least one valve (13a) connected to a corresponding actuator for a tool (11b) and a pump (410). The controller (17) is configured to operate in a first mode wherein the fluid flow is controlled through the at least one valve (13a), wherein said valve (13a) is a proportional valve, receive a pressure indication indicating a pressure in the hydraulic system (400) and determine if the pressure in the hydraulic system (400) is above a first mode threshold and/or if a pressure change fulfills a first mode condition, and if so operate in a second mode wherein the at least one valve (13a) is in an opened state and the fluid flow is controlled through the pump (410).

Pressure in subsea systems, and accumulators of the subsea systems, may be increased through the use of a supercharge cylinder to generate higher pressures from an initial pressure provided from a surface vessel. The supercharge cylinder may include a piston that can be stroked to increase pressure stored in accumulators located near subsea systems, such as a blowout preventer (BOP). The increased pressure provided by the supercharge cylinder may allow the same number of accumulators to be used in the subsea system but allow additional effective hydraulic fluid to be stored in the accumulators.

An apparatus comprising a synthetically commutated machine with one or more services, a prime mover coupled to the machine, a hydraulic circuit extending between the services and hydraulic loads to fluidically connect the services to the hydraulic loads such that groups of one or more services are fluidically connected to respective groups of one or more hydraulic loads. The apparatus configured such that the flow of hydraulic fluid to or from a group of services of the machine is controlled responsive to measuring a flow rate and/or pressure requirement of the hydraulic loads which are fluidically connected to the services, or receiving a demand signal indicative of a demanded pressure and/or flow rate based on a pressure and/or flow demand of hydraulic loads which are fluidically connected to the services.

A remote controlled demolition robot (10) comprising a controller (17) and at least one actuator (12) controlled through a hydraulic system (400) comprising at least one valve (13a) connected to a corresponding actuator for a tool (11b) and a pump (410). The controller (17) is configured to operate in a first mode wherein the fluid flow is controlled through the at least one valve (13a), wherein said valve (13a) is a proportional valve, receive a pressure indication indicating a pressure in the hydraulic system (400) and determine if the pressure in the hydraulic system (400) is above a first mode threshold and/or if a pressure change fulfills a first mode condition, and if so operate in a second mode wherein the at least one valve (13a) is in an opened state and the fluid flow is controlled through the pump (410).

A fluid pressure control circuit connected to first and second pumps includes: a switching valve configured to allow for and disconnect a communication between the first and second pumps; and first and second unloading valves configured to unload working fluid discharged from the respective first and second pumps. The switching valve and the first and second unloading valves are disposed in separate valve sections.

The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controller 6 includes a target pump pressure setting unit 32 which calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detector 20A/20B based on the operation amount signal and a pump flow rate upper limit setting unit 33 which calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal. The tilt amount of the hydraulic pump 2 is controlled based on the target pump delivery pressure calculated by the target pump pressure setting unit 32, the pump flow rate upper limit calculated by the pump flow rate upper limit setting unit 33, and the delivery pressure of the hydraulic pump 2 detected by a pressure detector 21.