A compressor system and method for operating a compressor system according to the compressed-air demand in an operating state of the vehicle utilize a compressor for producing compressed air for at least one compressed-air vessel, the delivery rate of the compressor being able to be adjusted at least indirectly by means of a control device. The control device is configured to be able to increase the delivery rate of the compressor beyond a defined operating maximum rate when there is exceptional demand.

A pump arrangement, in particular in a coating installation for the coating of components, such as a painting installation for the painting of motor vehicle body components, is provided. The pump arrangement includes a plurality of adjustable pumps for delivering a coating agent, e.g. for delivering a sealing agent for the sealing of weld seams on a motor vehicle body component. The pumps are connected in parallel such that the pumps extract the coating agent for delivery from a common inlet line and deliver said coating agent into a common outlet line. The arrangement further includes a control device for the open-loop or closed-loop control of one fluid variable at the outlet of the individual pumps, respectively, wherein the control device actuates the individual pumps individually, and/or a monitoring unit, which switches the pumps on and off non-simultaneously.

Peristaltic dosing pump including a pump housing, a dosing head, and a manual tool-less clamping arrangement for repeated detachable clamping of the dosing head on the pump housing. Reef aquarium LED array illumination units having a planar LED array for emitting illumination and a 3D stadium lens centrally mounted with respect thereto and underlying same for projecting a generally homogenous spectrum, diverging generally stadium shaped illumination beam.

An electric motor pump system includes a variable displacement pump, an electric motor connected to drive the variable displacement pump, a first control piston configured to limit an output pressure characteristic of the pump, and a second control piston controlled via a servo valve according to an output speed of the electric motor. In embodiments, the second piston is configured to maintain a substantially constant output flow of the pump as the output speed of the electric motor changes. With embodiments, the first and second control pistons may be configured to act on a yoke of the variable displacement pump.

Systems and methods to pump fracturing fluid into a wellhead may include a gas turbine engine including a compressor turbine shaft connected to a compressor, and a power turbine output shaft connected to a power turbine. The compressor turbine shaft and the power turbine output shaft may be rotatable at different rotational speeds. The systems may also include a transmission including a transmission input shaft connected to the power turbine output shaft and a transmission output shaft connected to a hydraulic fracturing pump. The systems may also include a fracturing unit controller configured to control one or more of the rotational speeds of the compressor turbine shaft, the power turbine output shaft, or the transmission output shaft based at least in part on target signals and fluid flow signals indicative of one or more of pressure or flow rate associated with fracturing fluid pumped into the wellhead.

A method for operating a fluid conveying device (4), in particular a pump, a fan, a compressor or a valve, by way of a control unit (14), wherein the fluid conveying device with a deactivated emergency running mode is switched on at least in the case of initial application of an operating power of the fluid conveying device, a setpoint rotational speed specification or a setpoint actuating value specification is transmitted to the fluid conveying device, and the emergency miming mode of the fluid conveying device is activated when the setpoint rotational speed specification or the setpoint actuating value specification exceeds a triggering value or the fluid conveying device is operated for longer than an activation duration with an invalid rotational speed or an invalid actuating value. Furthermore, the invention relates to a pump arrangement, a control unit, a computer program, and a machine-readable storage medium.

Systems and methods to pump fracturing fluid into a wellhead may include a gas turbine engine including a compressor turbine shaft connected to a compressor, and a power turbine output shaft connected to a power turbine. The compressor turbine shaft and the power turbine output shaft may be rotatable at different rotational speeds. The systems may also include a transmission including a transmission input shaft connected to the power turbine output shaft and a transmission output shaft connected to a hydraulic fracturing pump. The systems may also include a fracturing unit controller configured to control one or more of the rotational speeds of the compressor turbine shaft, the power turbine output shaft, or the transmission output shaft based at least in part on target signals and fluid flow signals indicative of one or more of pressure or flow rate associated with fracturing fluid pumped into the wellhead.

A method for determining a current wear (w) of a hydrostatic pump, particularly of a radial piston pump, with a variable-speed drive, where the pump is connected to a fluid passage, in which a fluid is pumped by the pump to create a current actual volume flow in the fluid passage. A current actual volume flow (Q.sub.act) is determined, by measuring the volume flow in the fluid passage at a predetermined drive-vector, a computed volume flow (Q.sub.comp) is determined, by a first computational method, at the predetermined drive-vector, and the current wear (w) of the pump is determined, by a second computational method, which relates the current actual volume flow (Q.sub.act) to the computed volume flow (Q.sub.comp).

An EHA system (10) for lifting or lowering a leg of an aircraft includes a hydraulic circuit (101) having a hydraulic actuator (a hydraulic cylinder 2) configured to lift or lower the leg, at least one electric hydraulic pump (3), and a hydraulic path, a pressure sensor (38, 83), a temperature sensor (84), and a control unit (a controller 9) configured to output a control signal for operating the electric hydraulic pump in leg lifting or lowering. The hydraulic circuit includes a pressure increasing element. The control unit performs health monitoring regarding the performance of the electric hydraulic pump based on the pressure of hydraulic fluid, the temperature of hydraulic fluid, and the speed of the electric hydraulic pump during operation of the electric hydraulic pump.

An anti-ripple injection method for injecting an anti-ripple signal into a control system of a pump is disclosed. The control system controls an electric motor via an electric motor drive, and the electric motor drives the pump. The anti-ripple signal causes pressure ripples in the pump output to be at least partially cancelled. The anti-ripple injection method comprises: injecting an anti-ripple signal of any waveform into the control system, the anti-ripple signal being represented by the following equation: f(θ)=Σ.sub.mA.sub.mcos(mθ+θ.sub.m), wherein θ is the rotation angle of the motor shaft, m is the order of a signal harmonic in the anti-ripple signal, A.sub.m and θm are parameters with respect to the m.sup.th signal harmonic. A control system of a pump including the anti-ripple injection apparatus, and a pump system including the control system are also disclosed.