A system (16) for pumping a fluid, comprising: a pump (17) comprising a suction side (18) and a discharge side (19); a motor (20) for driving the pump, which motor is drivingly connected to the pump via a shaft (21); a return line (23) providing a feed-back conduit for the fluid from the discharge side to the suction side; a control valve (24) controlling the flow of the fluid through the return line; and a first sensor device (27) for monitoring a first system parameter which is a function of the differential pressure across the pump. The system further comprises: a second sensor device (28) for monitoring a second system parameter which is a function of the torque of the pump; and a control unit (25) arranged to: receive monitored first system parameter values from the first sensor device and, for each monitored first system parameter value, identify a minimum allowable second system parameter value; receive monitored second system parameter values from the second sensor device and, for each monitored second system parameter value, compare the monitored second system parameter value with the identified minimum allowable second parameter value; and regulate the control valve such that the monitored second parameter value does not fall below the minimum allowable second parameter value. A method of operating such a system is also disclosed.

A multistage pump with axial thrust optimization is disclosed includes a pump discharge nozzle and a bypass system coupled to the pump discharge nozzle. The bypass system includes a throttle valve operatively coupled to the pump discharge nozzle, and a bypass line provided at the multistage pump. The bypass line is conducts flow from the throttle valve to a clearance gap of an axial thrust balancing arrangement. The throttle valve may be actuated to adjust a balancing flow through the bypass line such that pressure at the clearance gap is adjusted to increase and decrease fluid pressure at the clearance gap to balance axial thrust at different operating states of the multistage pump.

A compressor device includes a housing with a cavity. The compressor device includes a rotating group supported for rotation within the housing. The rotating group includes a shaft that supports a compressor wheel proximate a first end of the shaft. A second end of the shaft extends away from the compressor wheel through the cavity of the housing. The compressor device further includes a moisture evacuation system configured to remove airborne moisture from the compressor device. The moisture evacuation system includes a shaft passage extending through the second end of the shaft and a housing passage extending through an outer wall of the housing. The shaft passage is fluidly connected to the cavity. The housing passage is fluidly connected to the shaft passage. The moisture evacuation system is configured to direct the airborne moisture from the cavity, through the shaft passage, and out of the housing via the housing passage.

A centrifugal pump device has at least one impeller (16), a circulation connection between a delivery side (22) of the at least one impeller (16) and a suction side (20) of the at least one impeller (16), and a valve arrangement (30, 46) in said circulation connection (44, 54). The valve arrangement (30, 46) has a first valve mode providing a pressure dependent shut-off valve (46) in the circulation connection. The valve arrangement (30, 46) allows a change between the first valve mode and at least one further valve mode. The at least one further valve mode provides at least one fixed closing degree of the circulation connection (44, 54).

A fluid pump includes a housing; an inlet passage; an outlet conduit; a pumping element within the housing; and a check valve assembly. The check valve assembly includes a valve stem within the outlet conduit such that a flow path is created radially between the outlet conduit and the valve stem, the valve stem moving along a check valve assembly axis between a closed position and an open position. The flow path includes a first restriction which increases velocity of fluid passing through the flow path; a first expansion, downstream of the first restriction, which decreases velocity of fluid passing through the flow path; a second restriction, downstream of the first expansion, which increases velocity of fluid passing through the flow path; and a second expansion, downstream of the second restriction, which decreases velocity of fluid passing through the flow path.

A device is provided for controlling the load of a mobile fluid pump which at an exit side is coupled to an outlet conduit, including an assembly that is a mobile unit and that includes an inlet conduit that can be coupled to the outlet conduit, which inlet conduit branches into a first conduit part and a second conduit part. A controllable closing valve is accommodated in the first conduit part and a turbine is accommodated in the second conduit part. A pressure sensor is accommodated in the inlet conduit, the first conduit part or the second conduit part, further including a generator that is drivable by the turbine and a measurement and control circuit that can be coupled to the pressure sensor and the controllable closing valve.

A pump device is proposed for arrangement on a recirculation line of an industrial water system including a feed pump, a check valve and a bypass line for the check valve. The bypass line is arranged in parallel to the check valve and wherein a combination of the check valve and bypass line is arranged in series to the feed pump.

A method of operating a system (16) for pumping a fluid, which system comprises a pump (17) comprising a suction side (18) and a discharge side (19); a motor (20) for driving the pump, which motor is drivingly connected to the pump via a shaft; a recirculation conduit (23) providing a fluid path for the fluid from the discharge side to the suction side of the pump; and a control valve controlling the flow of the fluid through the recirculation conduit, which method comprises the steps of: mapping a plurality of minimum torque diagrams for the pump, where each minimum torque diagram identifies the minimum allowable torque of the pump as a function of an operational parameter of the pump, e.g. the differential pressure over the pump; from said plurality of minimum torque diagrams, identifying the minimum torque diagram best representing the current operation of the pump; monitoring said operational parameter of the pump and, from the minimum torque diagram best representing the current operation of the pump, identifying a minimum allowable torque value corresponding to a monitored value of said operational parameter of the pump, e.g. a monitored differential pressure value; monitoring the torque of the pump and comparing a monitored torque value with the identified minimum allowable torque value; and regulating the control valve such that the monitored torque value does not fall below the minimum allowable torque value. A corresponding pumping system is also disclosed.

A pump assembly is disclosed comprising a pump body having a first pump stage housed in the pump body including a fluid inlet and a first and a second fluid outlet. A flow feed chamber is housed in the pump body in fluid communication with the second fluid outlet. A second pump stage housed in the pump body is in fluid communication with the flow feed chamber and includes at least one fluid outlet connected to the second pump stage. A valve assembly is operable into a first position to fluidically connect the fluid inlet through the first pump stage to the first fluid outlet. The valve assembly is further operable into a second position to fluidically connect the first pump stage to the second fluid outlet and the flow feed chamber and the flow feed chamber fluidically connected to the at least one fluid outlet through the second pump stage.

A centrifugal pump device has at least one impeller (16), a circulation connection between a delivery side (22) of the at least one impeller (16) and a suction side (20) of the at least one impeller (16), and a valve arrangement (30, 46) in said circulation connection (44, 54). The valve arrangement (30, 46) has a first valve mode providing a pressure dependent shut-off valve (46) in the circulation connection. The valve arrangement (30, 46) allows a change between the first valve mode and at least one further valve mode. The at least one further valve mode provides at least one fixed closing degree of the circulation connection (44, 54).