A hydrostatic axial piston pump for a hydrostatic traction drive has an adjusting unit for adjusting the stroke volume. The adjusting unit has an actuating cylinder with two counteracting actuating pressure chambers. An actuating pressure can be set in each actuating pressure chamber via a separate pressure reducing valve, the said actuating pressure depending on and preferably being proportional to a current intensity on a respective solenoid of the respective pressure reducing valve. The two current intensities can be calculated via an electronic control unit on a model basis as a function of a speed and of an operating pressure of the axial piston pump and as a function of an operating element for a driver's request, e.g. an accelerator pedal.

A fracturing apparatus may include a first plunger pump including a first power end and a first hydraulic end; a prime mover including a first power output shaft; and a first clutch including a first connection portion and a second connection portion. The first power end of the first plunger pump includes a first power input shaft, the first connection portion is coupled to the first power input shaft, the second connection portion is coupled to the first power output shaft of the prime mover.

A piston pump group for a brake system and a control method thereof are provided, and the piston pump group includes: a piston, a pump body provided with an operating chamber, and a transmission mechanism used for driving the piston to move in the operating chamber, where the transmission mechanism includes a lead screw transmission assembly, a follower, and a planetary gear assembly used for transmitting power to the lead screw transmission assembly, the follower is fixedly connected to the piston, the lead screw transmission assembly is used for driving the follower to move relative to the operating chamber, and a limiting member used for limiting the movement of the follower is disposed between the lead screw transmission assembly and the follower.

Aspects are provided for positive displacement pumps and methods and systems for controlling such pumps for dispensing at a flow rate based on a downstream flow sensor. A pump controller determines a targeted motor speed for a flow rate set point based on a flow rate function. The pump controller determines a predicted movement time for a motor of the pump to change from a current motor speed to the targeted motor speed, a predicted wait time to reach a flow rate corresponding to the targeted motor speed, and a measurement time after the wait time. The pump controller controls the positive displacement pump according to consecutive control cycles, each control cycle includes a pump movement sub-cycle, a wait sub-cycle, and a measurement sub-cycle. The pump controller determines a measured flow rate during the measurement sub-cycle. A subsequent control cycle is based on the measured flow rate.

A method that includes an electronic application identifying a downlink sequence for execution by a surface control system of a drilling rig, with the sequence including target output values of a mud pump system and/or a drive system. The method includes instructing the control system to operate in accordance with the sequence. The application receives measured output values of the mud pump system and/or the drive system and calculates differences between the target and measured output values. When the differences are within a level of tolerance, then the application identifies the control system as compliant; and when the differences are greater than the level of tolerance, then the application identifies the control system as non-compliant. The method also includes the application receiving data from a BHA of the drilling rig and determining, based on the data received, if a downlink to the BHA was successful.

An electric pump system and method of operating the same involves pumping a fluid through a fluid passageway defined in a mechanical pump from a pump inlet to a hollow shaft of a motor, through the hollow shaft to an internal motor cavity defined by a housing of the motor, and through another fluid passageway defined in the motor housing and mechanical pump that leads to a pump outlet. The system and method further involve pumping the fluid through another fluid passageway defined in the mechanical pump from yet another pump inlet to the pump outlet. The temperature of fluid exiting the hollow shaft can be assessed and used by an electronic control unit (ECU) of the electric pump system to control the same. The electric pump system can be part of a cooling and lubrication system for an electric vehicle transmission, gearbox, differential or transfer case, for example.

System/method for real-time monitoring and control of pump operations at a well provide a pump control system that uses pump fillage with a proportional-integral-differential (PID) based algorithm to control positive displacement pump operations. The pump control system/method obtains measured or inferred pump speed from available pump speed data and, using certain pump characteristics provided by the well operator, calculates a theoretical fluid flow rate based on the pump speed. The pump control system/method thereafter compares the calculated theoretical fluid flow rate to a measured or observed fluid flow rate to calculate a pump fillage. The calculated pump fillage is then provided as a process input to the PID based algorithm along with a desired pump fillage from the well operator. The PID based algorithm processes the calculated pump fillage and the desired pump fillage using tuning parameters to determine an optimum pump speed based on the desired pump fillage.

A dynamic compressor control is provided. The dynamic compressor control includes sensors to sense operating parameters of a compressor and a compressor analytic software package. The compressor analytic software package uses the sensed operating parameters of the compressor to generate key performance indicators. The key performance indicators are used to calculate process variables for the compressor. The dynamic compressor control uses the sensed operating parameters and the process variables calculated from the key performance indicators to provide operating alarms and/or shutdowns.

A compressor that includes a casing, a compression mechanism provided inside the casing to compress a refrigerant, a rotary shaft transmitting a rotational force to the compression mechanism from a drive source provided outside the casing, a clutch connecting the drive source and the rotary shaft by a magnetic force generated when electric power is applied to the clutch and disconnecting the drive source and the rotary shaft by losing the magnetic force when the electric power applied thereto is cut off, and a rotation measurement means for receiving the magnetic force from the clutch to measure a change in magnetic flux according to the rotation of the rotary shaft and measure a rotational speed of the rotary shaft. Thus, it is possible to measure the rotational speed of the rotary shaft without including a permanent magnet.

A pumping system and method including a flow locking feature. A pump controller includes a user interface configured to initially receive and set a plurality of programmed flow rate settings, a maximum locked flow rate, and a minimum locked flow rate. The pump controller is also configured to disable resetting of the maximum flow rate and the minimum flow rate once they are initially received and set and to allow resetting of the plurality of programmed flow rate settings throughout operation of the pumping system. The pump controller is further configured to operate a pump motor in order to maintain a first flow rate set by one of the plurality of programmed flow rate settings as long as the first flow rate is between the minimum locked flow rate and the maximum locked flow rate.