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.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system. The rotary pump includes a plunger and optional stopper formed from a two-shot molding process, and including seals overmolded onto the head of the plunger and the head of the optional stopper.

A multi-channel positive displacement piston pump apparatus includes a motor and a plurality of positive displacement piston pumps driven by the motor. The plurality of pumps are aligned in a stacking direction, and each pump has an intake port and an outlet port, wherein the intake ports and the outlet ports of all pumps face in the same direction generally perpendicular to the stacking direction. In a method for retrofitting a positive displacement piston pump for use in a multi-channel pumping apparatus, an outlet port of a pump housing of the pump and a flush outlet port of the pump housing are plugged and an alternative fluid path is formed within the pump housing. The outlet port is disposed in line with an inlet port of the pump housing but on an opposite side of the pump housing. The flush outlet port is disposed in line with a flush inlet port of the pump housing but on an opposite side of the pump housing. In this way, the alternative fluid path is formed between the inlet port and the flush inlet port.

The present invention relates to a device for dispensing liquid product, comprising a fixed part and a moving part; the fixed part comprising an intake orifice, a delivery orifice, a body comprising a cavity into which said orifices open, said cavity being able to partially house the moving part, the remaining volume forming an emptying chamber; the moving part being able to move partially in the cavity of the fixed part and comprising a piston, a piston driving element, an axial spring, a duct extending along the circumference of the piston, said duct allowing positions that allow fluidic communication between the emptying chamber and just one of said orifices and allowing switchover positions in which all fluidic communication between the emptying chamber and each of said orifices is forbidden, a cam able to convert the rotation of the drive element into an oscillatory-rotary movement of the piston. The axial spring is able to absorb energy during a liquid intake phase and to restore same during a liquid delivery phase, said spring being positioned around the piston which is on the moving part situated inside the cavity of the body.

Systems and methods for analyzing an infusion pump are provided. One infusion pump analyzer includes a fluid flow path configured to be coupled to an infusion pump to be tested and a pair of fluid chambers. The infusion pump analyzer further includes dual linear piston pumps coupled with the pair of fluid chambers and the fluid flow path to control the flow of fluid therethrough, and a valve coupled with the pair of fluid chambers and configured to rotate to selectively fill and drain the pair of fluid chambers.

A compressor (10) for compressing air for a compressed air system of a motor vehicle has a cylinder housing (14) and a cylinder head (16) connected thereto. A compressor piston is moveable in oscillation up and down in a cylinder in the cylinder housing (14). A lamella (34, 36) is received in a depression (38) in an underside (30) of the cylinder head (16) facing the compressor piston. The delivery rate of the compressor (10) can be regulated by closing or opening a control channel (60, 60′) in the cylinder head (16) via the lamella. A bearing end (44) of the lamella (34, 36) is hinged in a pivotably guided manner on a bearing contour (54) of this depression (38). As a result, a separate bearing journal for pivotable mounting of the lamella (34, 36) on the cylinder head (16) may be omitted.

Assembly for dispensing a liquid, in particular a colorant for paint, comprising a container for holding a liquid, a pump, a valve, at least one dispense opening, and comprising or associated with a controller arranged to operate the pump and the valve to withdraw liquid from the container and to dispense liquid via the opening and to operate the pump and the valve to purge liquid from the pump to the container via the dispense opening.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system.

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.

A disposable medical flow-regulating assembly includes flow-directing units, with multiple fluid-flow lines entering each of the flow-directing units. The flow-directing units are interconnected by a fluid-flow line that extends between them. Each of the flow-directing units includes a rotational insert member that regulates which of multiple flow passages through the flow-directing unit is open and which are closed, based on the angular position of the insert member.