In an aspect, there is provided a pump impeller assembly that includes a first impeller portion arranged to drive a fluid through a fluid conduit, a second impeller portion movable between a more-rotationally engaged position in which the second impeller portion has a first amount of rotational engagement with the first impeller portion, and a less-rotationally engaged position in which the second impeller portion has a second amount of rotational engagement with the first impeller portion that is less than the first amount of rotational engagement, and an actuator operatively connected to the second impeller portion and configured to drive movement of the second impeller portion between the more-rotationally engaged position and the less-rotationally engaged position based on a fluid property.

Assemblies and methods for measuring the nose gap of a centrifugal pump may include using an ultrasonic transducer coupled to a suction liner of the centrifugal pump to measure the nose gap of a slurry pump for pumping a slurry mixture, which can include sand, rock, and other particulates. A signal analyzer may be used to determine the size of the nose gap based on scatterings and reflections of an ultrasonic pulse passing into or through the adjustable liner, through the medium being pumped, and reflected from the impeller. The assemblies and methods may provide an ability to obtain a real-time measurement of the nose gap during operation of the centrifugal pump, which may result in an ability to adjust nose gap to provide more efficient operation of the pump and reduced wear rates.

The present invention relates to a method for controlling a pump, in particular a centrifugal pump, during pumping of a liquid, comprising the following steps: fixing a setpoint value of a flow rate of the pump; measuring an inlet pressure of the liquid upstream of the pump and an outlet pressure of the liquid downstream of the pump; determining a setpoint value of a rotational speed of the pump from a performance map of the pump, wherein the fixed setpoint value of the flow rate and a difference between the outlet pressure and the inlet pressure are incorporated into the performance map as input values; and setting the rotational speed of the pump to the setpoint value of the rotational speed. Furthermore, the invention relates to a corresponding device for controlling a pump.

A method for controlling a hydraulic pumping system that includes a centrifugal pump operating at a functional point. The method uses parameters of the centrifugal pump at the functional point and end-of-lines characteristics of the centrifugal pump to determine an updated Net Positive Suction Head Required, NPSH.sub.r, value.

A pumping device for pumping liquids includes a centrifugal pump with a radially pumping pump wheel having a hollow center, and is configured to remove accumulations of gas from the interior of the pump. The pumping device includes a detecting device for detecting a first operating parameter, a sensor for measuring a second operating parameter, and a control unit for controlling the pump. The control unit is configured to control the operation of the pump so as to remove accumulations of gas from the hollow center of the pump during liquid pumping operation.

A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of on portions and a plurality of off portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the on portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the on portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

A rotary unit selectively adds additives to water in a conventional bathtub automatically without a bather having to touch the additives or leave the conventional bathtub to get the additives. The rotary unit includes a plurality of pressurized canisters and a controller. The plurality of pressurized canisters are configured in a circular configuration and are disposed directly adjacent to, and communicatable with, the conventional bathtub. Each pressurized canister contains a different one of the additives. The controller is in communication with the plurality of pressurized canisters, and as such, the controller is utilized to choose one of the additives to add to the water in the conventional bathtub automatically without the bather having to touch the chosen one of the additives or leave the conventional bathtub to get the chosen one of the additives.

A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of on portions and a plurality of off portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the on portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the on portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

An electric water pump having a motor with an axially moveable rotor unit. A rotary pump member is fixed for axial movement with the rotor unit to vary its position within a pump chamber so as to vary the flow rate through the pump chamber.

A blower assembly for advancing the flow of air in an air flow device at a selected one of a plurality of air flow rates is provided. The blower assembly includes a blower housing defining a body thereof and a wall of the blower housing moveably secured to the body, a blower wheel rotatably mounted to the blower housing and a motor for rotating the blower wheel at a selected one of a plurality of rotational speeds. The blower assembly further includes a motion device secured to the body and to the wall. The motion device moves the wall relative to the body to a selected one of a plurality of distinct wall positions. The motor rotates the blower wheel at a selected one of a plurality of rotational speeds. A controller calculates optimum wall position and rotational speed to provide for minimal energy usage rate.