A hydraulic fracturing system can include valve apparatuses that control the delivery of fluid to high-pressure pumps that supply the fluid to a wellhead. The valve apparatuses can receive electronic signals from a control system to regulate the flow rate of the fluid to the high-pressure pumps. In one or more examples, the flow rate of the fluid can be controlled such that proppant in the fluid remains in solution.

Methods and breast pump devices for simultaneous pumping and feeding breastmilk in the nursing position and quantification of breastmilk consumption are provided. A breast pump device includes a nipple shield for receiving a nipple, a housing having a throughput aperture and a fluid path, the fluid path extending from the nipple shield to the throughput aperture, and a negative pressure source. In some embodiments, the housing further includes a gate to control the quantity of breastmilk displaced to a baby. In some embodiments, the gate operates to respond to the amount of breastmilk displaced to the baby, and thereby allows for quantification. In some embodiments, the quantity of breastmilk displaced is also recorded.

A method for correcting pump model includes: obtaining a pump model for a pump, the pump model including a Q-P curve and a Q-H curve at each of a plurality of frequencies; at each frequency, determining a power error based on a zero-flow-rate power or an actual operating point of the pump under one of the frequencies; and determining a corrected pump model based on the pump model and the power error. The determination of the corrected pump model includes: at each frequency, determining a corrected Q-P curve to be the Q-P curve shifted by the power error; determining a Q-H-P surface based on the corrected Q-P curves and the Q-H curves at all the frequencies; at each frequency, determining a head error based on the surface and the power error; and at each frequency, determining a corrected Q-H curve to be the Q-H curve shifted by the head error.

The invention relates to a medical treatment apparatus comprising a tube set 20, a peristaltic pump 6 for conveying fluid, and a monitoring apparatus 15 for monitoring the occlusion of the positive displacement elements 13A, 13B of the peristaltic pump. In addition, the invention relates to a tube set 20 for a medical treatment apparatus, and to a method for monitoring the occlusion of the occlusion elements of a peristaltic pump for conveying a fluid for a medical treatment apparatus. The invention is based on the fact that the occlusion of the positive displacement elements 13A, 13B of the peristaltic pump 6 is monitored in order to monitor the fluid flow in the hose line 5. For this purpose, the electrical resistance or a variable which correlates with the electrical resistance is measured between a first and a second electrode 16A, 16B, the first electrode 16A being arranged on the hose line 5 upstream of the occlusion elements 12 of the peristaltic pump 6 and the second electrode 16b being arranged on the hose line downstream of the occlusion elements such that an electrical contact is produced between the first and second electrode 16A, 16B and the fluid flowing in the hose line 5. The electrodes 16A, 16B are preferably integral component parts of a connecting piece 10, by means of which the hose segment 5A to be inserted into the peristaltic pump 6 is fixed in the form of a loop.

One or more wellbore servicing operations may require the pulsed delivery of a wellbore servicing fluid. To optimize efficiency and effectives of a given wellbore servicing operation a concentrated proppant stimulation fluid may be pumped downhole at a predetermined time interval from dedicated pumping units or positive displacement pumps. The flow rate of proppant in the concentrated proppant stimulation fluid pumped from these dedicated pumps may simulate a square-wave. The desired or determined square-wave or output may be predetermined and any one or more dedicated pumps may be associated with a given time interval and pumping cycle or phasing such that the overall flow of proppant from all of the dedicated pumps simulates a square-wave. Clean fluid from one or more clean fluid pumps may be combined with the concentrated proppant stimulation fluid to maintain a target flow rate of fluid downhole.

A method controls the start-up of an oil pump of a gearbox by a brushless electric motor that has no position sensor. The stator coils are powered from the off mode in a constant-current open-loop control sequence until the pump reaches a speed threshold at which speed regulation switches over to closed-loop control on a setpoint corresponding to the lubrication flow rate required to ensure the reliability of the gearbox, but without in so doing exceeding a current threshold indicative of pump seizure, at which point motor control switches back over to the constant-current open-loop control sequence. The open-loop current setpoint is higher than the threshold for switching over to closed-loop control so that in the open-loop control mode the motor torque available at the pump is higher than in the closed-loop control mode.

Provided is a washing agent pump and a laundry treating apparatus having the same. The laundry treating apparatus may include a cabinet, a tub provided within the cabinet, a rotary tub provided within the tub in a rotatable manner, and a washing agent supply unit. The washing agent supply unit may include a storage container to store a liquid washing agent including a liquid detergent or a liquid softener, the storage container being slidably provided in the cabinet, a washing agent supply passage having one side connected to the storage container and another side connected to the tub, and a washing agent delivery device provided in the washing agent supply passage to deliver the liquid washing agent to the tub.

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 pumping system pumps material downhole, for example, to perform a fracturing operation. The pumping system comprises one or more variable speed engines, one or more variable displacement hydraulic pumps and one or more intensifiers. According to the desired or required load, the speed of the engine is set at an optimal or most efficient operating speed. The volumetric displacement of the variable displacement hydraulic pump is set to provide the desired output volume and pressure of the material from the intensifier. Varying the speed of the engine and the volumetric displacement of the variable displacement pump allows for the pumping system and in particular the engine to operate at an optimal efficiency which reduces at least fuel costs and wear and tear on components.

An automatic self-driving pump system features a pump/motor/drive detector and an automatic self-driving and control design/setup module. In operation, the pump/motor/drive detector receives sensed signaling containing information about a pump/drive for operating in a hydronic pump system, e.g., stored in and sensed from a signature chip or barcode installed that can be scanned by a scanner, and provides corresponding database signaling containing information about parameters for providing automatic pump control design, setup and run to control the pump/drive for operating in the hydronic pump system, based upon the sensed signaling received. The automatic self-driving and control design/setup module receives the corresponding database signaling, and provides control signaling containing information for providing the automatic pump control design, setup and run to control the pump/drive for operating in the hydronic pump system, based upon the corresponding database signaling received.