A liquid treatment apparatus (2), comprising a pumping device (3) configured to pump a liquid (4) to be treated into at least one treatment chamber (6) comprising treatment equipment (9) configured to perform UV-light treatment of the liquid (4) flowing through the at least one treatment chamber (6). The liquid treatment apparatus (2) comprises an air trap vessel (5) arranged upstream of said pumping device (3) and provided with an inlet connection (22) for receiving liquid (4) to be treated and a first outlet connection (24) for connection and liquid supply to said pumping device (3). The air trap vessel (5) is configured to prevent air bubbles from being sucked into the pumping device (3) and to be at least partly filled with a priming liquid (23) before the pumping device (3) is started and the liquid treatment is initiated, and that the first outlet connection (24) being arranged below surface level of the priming liquid.

A method of operating a submersible pumping system includes the steps of placing the pumping system in a normal mode of operation and then detecting the possible presence of a gas slug in proximity to the pumping system by measuring a decrease in the load on the motor. Once the possibility of a gas slug has been detected, the method continues by placing the pumping system in a reduced speed cycle. The pumping system is kept in the reduced speed cycle until the absence of a gas slug in proximity to the pumping system is detected by evaluating two independent conditions within the pumping system.

A centrifugal pump assembly (2) includes an impeller, an electric drive motor (4), driving the impeller (12), and a back-flow channel (24), forming a flow connection from a delivery side (18) to a suction side (16). A valve (26), in a pressure-dependent manner, closes the flow connection. A control device (28) adjusts/sets the speed (n) of the drive motor (4), and is configured with a venting function for venting the centrifugal pump assembly (2) on operation. According to the venting function, after the detection of an air accumulation, the speed (n) of the drive motor (4) is automatically reduced, and subsequently the speed (n) is rapidly increased again. A method is also provided for removing an air accumulation from a centrifugal pump assembly during operation, which method includes reducing the speed (n) of the centrifugal pump assembly and subsequently rapidly increasing the speed (n) of the centrifugal pump again.

A method of de-watering during intermittent dry running periods with a self-priming centrifugal pump is presented. Centrifugal pumps, as opposed to diaphragm pumps, are advantageous because they are less expensive and can provide greater capacity. The shaft seals are sensitive, however, to frictional heating when water flow is interrupted. In some situations, this fractional heating may desiccate self-priming. The inventive concept provides a continuous stream of pressurized water moving through the pump to cool the seal and sustain priming capability without substantially impairing the ability of the pump to resume wet operation.

A liquid treatment apparatus (2), comprising a pumping device (3) configured to pump a liquid (4) to be treated into at least one treatment chamber (6) comprising treatment equipment (9) configured to perform UV-light treatment of the liquid (4) flowing through the at least one treatment chamber (6). The liquid treatment apparatus (2) comprises an air trap vessel (5) arranged upstream of said pumping device (3) and provided with an inlet connection (22) for receiving liquid (4) to be treated and a first outlet connection (24) for connection and liquid supply to said pumping device (3). The air trap vessel (5) is configured to prevent air bubbles from being sucked into the pumping device (3) and to be at least partly filled with a priming liquid (23) before the pumping device (3) is started and the liquid treatment is initiated, and that the first outlet connection (24) being arranged below surface level of the priming liquid.

Various downhole tools are discussed, including intake and gas separators for a downhole rotary pump. Multiple intakes configured in parallel and series are discussed. along with compact axial length gas separators, and gas separators that remove gas in novel ways. Related apparatuses and methods are discussed.

An automotive electric liquid pump module for pumping a coolant liquid in a coolant circuit of an automobile. The automotive electric liquid pump module includes a first electrical flow pump unit having a flow pump wheel which is directly driven by an electric motor, and a passive deaerator unit having a liquid inlet, a liquid outlet, a deaerator housing which defines a first widened deceleration chamber, and a deaeration opening which is arranged at a vertical top of the first widened deceleration chamber. The deaerator housing is mechanically directly and stiffly connected to the electrical flow pump unit.

Intake and gas separators for a downhole rotary pump define a fluid flowpath and comprise two or more intake stages arranged in parallel, with two or more of the intake stages each having one or more impeller. Multiple intakes may be configured in parallel and series, in some cases being provided as compact axial length gas separators.

Intake and gas separators for a downhole rotary pump define a fluid flowpath and comprise two or more intake stages arranged in parallel, and two or more of the intake stages each have one or more impellers and one or more inlet holes.