Pressure measurement system (e.g., for an extracorporeal treatment system), method and pressure pod apparatus including a position sensor for use in repositioning a diaphragm that separates a liquid side cavity from a transducer side cavity (e.g., operatively connected to a pressure transducer); the liquid side cavity being in fluid communication with an inlet and an outlet.

An electro-hydraulic pump for hydrodynamic compression tools which comprises a pump housing carrying an electric motor and a hydrodynamic group for pressurizing a hydraulic liquid, a control circuit for controlling the electric motor, a flexible pressure hose connected to the hydrodynamic group, and a work head of the tool to communicate the hydraulic liquid pressure to the work head. A flexible control cable connects the control circuit in the pump housing to a hand held remote control. The hand held remote control comprises an actuating button for starting the electric motor and a button for selecting an operation mode of the electro-hydraulic pump from a plurality of pre-set operation modes, as well as a multifunction display which shows the selected operation mode.

A control valve for a pump for delivering a fluid. The control valve includes: a valve housing which delineates a piston chamber; a piston which can be moved within the piston chamber; and a fluid channel which ports into the piston chamber via a port opening, wherein the port opening defines a port control edge. The valve housing includes a recess which extends into the fluid channel, wherein the recess defines a recess control edge which is axially offset with respect to the port control edge, and/or the piston includes a piston recess which defines a piston recess control edge.

Systems and methods are provided for a demand-based hydraulic system. A clutch is positioned between a hydraulic pump and an engine. The clutch is selectively engaged to power the hydraulic pump based on a level of demand for hydraulic power. A control system is also provided to control the clutch and/or the pump in accordance with a plurality of operating mode.

A regulating device for use with a pump that has a hydraulically adjustable displacement volume, wherein the regulating device includes an inflow port, a return flow port, an actuating port, a control port, a first control slide valve, and a second control slide valve. The first control slide valve is linearly movable with respect to a center axis, the first control slide valve defining first and second orifices, which are adjustable jointly and in opposite directions. The second control slide valve is linearly movable and defines third and fourth orifices, which are adjustable jointly and in opposite directions. The second control slide valve is accommodated in a linearly movable manner within the first control slide valve.

A hydrostatic axial piston pump has adjustable swept volume and is configured for fluidic connection to a hydraulic motor of a hydrostatic propulsion drive in a hydraulic circuit. The hydrostatic axial piston pump includes an adjusting unit configured to adjust the swept volume. The adjusting unit has an actuating cylinder with a first actuating pressure chamber, in which a first actuating pressure can be set via a first pressure reducing valve. The first actuating pressure is dependent on a first current at a first electromagnet of the first pressure reducing valve. An electronic control device is configured to store a model of the first current in a manner which is dependent on a requested speed.

Most multistage compressors specify a maximum inlet pressure that may be supplied to the compressor to stay within designed limits. If the supply gas to be compressed is at a higher pressure than the specified maximum inlet pressure, then its pressure must be reduced before connecting it to the compressor. This pressure reduction is inefficient. The present invention avoids reducing the inlet pressure by routing the supply gas directly to the appropriate compression stage depending on its inlet pressure such that the compressor loads are still within the specified limits of the equipment.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A pump displacement control device includes: a servo piston that changes a tilt angle; a flow rate control spool that is displaced corresponding to an input pressure; a power control spool that is displaced corresponding to a discharge pressure of the pump; a control pressure regulating spool that regulates a control pressure which controls the servo piston; and a feedback lever connected to the servo piston and the control pressure regulating spool. The feedback lever directly abut on either one of the flow rate control spool or the power control spool for regulating the control pressure.

A method of differentially steering a hydraulically driven vehicle includes measuring left and right swash plate angles of pumps which drive left and right wheels of the vehicle and if the angles are different from one another and the larger swash plate angle is equal to or exceeds a threshold value then reducing the larger swash plate angle. If the larger swash plate angle is between the threshold value and a lower limit, or below the lower limit the swash plate angle is increased. Control systems and vehicles include swash plate angle sensors and actuators in communication with a controller which effects the steering control method.