The disclosure relates to a method for estimating a flow out of at least one fluid pump for injecting fluid in a well, comprising: determining a calculation model for the flow rate of a pump exiting the at least one pump, said calculation model permitting the calculation of the flow rate in function of at least one calculation parameter (p, SPAM) related to the at least one fluid pump; then providing at a plurality of measuring times (t.sub.m), a set of measurement values (P.sub.DH,m, P.sub.B,m, SPM.sub.DH,m, SPM.sub.B,m) representative of said at least one calculation parameter; then estimating (86) the flow rate exiting the pump in function of the model and of said at least one calculation parameter.

A variable fluid flow hydraulic pump including one or more displacement bodies having a fixed volume chamber. Within this fixed volume chamber a piston cycles or reciprocates thus providing for the movement of fluid. Also present is a low pressure valve connecting said displacement chamber with the low pressure side. Additionally, a high pressure valve may be provided on the high pressure side. The low pressure valve is provided with an adjustable element or Fcontrol providing an opening force thereon and further providing a closing force, which periodically increases during the pumping stroke and decreases during the suction stroke of said piston reciprocating within the displacement body and further includes an element to supply fluid from the low pressure side to said fixed volume chamber of the displacement body while the pressure in the displacement chamber is less than that of the low pressure side.

A variable fluid flow hydraulic pump including one or more displacement bodies having a fixed volume chamber. Within this fixed volume chamber a piston cycles or reciprocates thus providing for the movement of fluid. Also present is a low pressure valve connecting said displacement chamber with the low pressure side. Additionally, a high pressure valve may be provided on the high pressure side. The low pressure valve is provided with an adjustable element or Fcontrol providing an opening force thereon and further providing a closing force, which periodically increases during the pumping stroke and decreases during the suction stroke of said piston reciprocating within the displacement body and further includes an element to supply fluid from the low pressure side to said fixed volume chamber of the displacement body while the pressure in the displacement chamber is less than that of the low pressure side.

A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

A hydraulic machine (1) comprising first and second brake elements (92, 93), a spring washer (65) tending to urge the first and second brake elements (92, 93) in a braking direction, and a brake release piston (61) configured to act on the spring washer (65) in a direction opposing the braking direction, the hydraulic machine being characterized in that the brake release piston (61) comprises a primary brake release piston (61a) associated with a primary brake release chamber (62a), and a secondary brake release piston (61b) associated with a secondary brake release chamber (62b), said primary and secondary chambers (62a, 62b) extending radially around the shaft (2) in such a manner that projections of the primary brake release chamber (62a) and of the secondary brake release chamber (62b) onto a plane perpendicular to a longitudinal axis (X-X) defined by the axis of rotation of the hydraulic machine (1) are superposed, at least in part.

A hydraulic radial piston device includes a housing, a pintle having a pintle shaft, a rotor mounted on the pintle shaft and defining a plurality of cylinders, and a plurality of pistons displaceable in the cylinders. The radial piston device further includes a piston ring that provides an interface for the pistons. The radial piston device includes various configurations for improving the performance and efficiency of the device.

The invention relates to a hydrostatic radial piston motor, in particular a hydrostatic radial piston motor for actuating a differential cylinder. According to the invention, the hydrostatic motor in radial piston configuration comprises a control stud in a housing, the hydrostatic motor having three hydraulic working connections. The first working connection can be connected to the piston-end of a differential cylinder, while the second working connection can be connected to the rod-end of the differential cylinder. Finally, the third working connection can be connected to a tank. Owing to this arrangement, the differential cylinder can be directly operated with the aid of a single hydrostatic motor, with it being possible to forgo interposing proportional or control valves.

The present invention provides a method and system for providing on-site electrical power to a fracturing operation, and an electrically powered fracturing system. Natural gas can be used to drive a turbine generator in the production of electrical power. A scalable, electrically powered fracturing fleet is provided to pump fluids for the fracturing operation, obviating the need for a constant supply of diesel fuel to the site and reducing the site footprint and infrastructure required for the fracturing operation, when compared with conventional systems.

An apparatus for delivery of fluids to a patient includes an inlet tube and an outlet tube connected to each other at an angular joint. A rotary valve and a piston are fitted to the angular joint forming a chamber. The rotary valve is provided with a priming channel notch and a pumping notch. For priming operation with the fluid delivery apparatus, a user sets the rotary valve to a priming position. During pumping operation, the rotary valve rotates in coordination with the piston to transfer a quantum of fluid from the inlet tube to the outlet tube via the chamber. A second piston is optionally provided on the outlet tube for smoothing out flow rate pulsations.