Abstract: A controller for controlling a frequency inverter of a positive displacement pump motor of a positive displacement pump. The controller comprises a control unit configured to produce a control variable (Ys) for a frequency inverter of a positive displacement pump motor depending on a reference variable (W) and a first actual operating parameter (X). According to the invention, the control unit is associated with logical means having a first threshold value defining means that are designed to determine at least one first threshold value (YGrenzmax, YGrenzmin) depending on the first actual operating parameter (X) and/or at least one further actual operating parameter (XH, YH, YHH) that could lead to a failure state of the positive displacement pump when exceeded or fallen short of.

Abstract: The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (YS) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (YS).

Abstract: The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (Ys) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (Ys).

Abstract: An operational control device is disclosed for a positive-displacement pump having a motor, means for actuating the motor, state sensor means for detecting an actual operating parameter (e.g., pressure) of the pump, and operating mode means for controlling an operating mode of the pump. A first actuating mode of the operating mode means is set by the actuating means below a first operating-parameter threshold value (P1). This mode brings about a constantly rising pump pressure in the direction of an operating-parameter setpoint value (Pset) in a variable manner, which is dependent on a detected change in the operating parameter over a predefined time interval. A second actuating mode is set as normal operation to the operating-parameter setpoint value by the actuating means above the first operating-parameter threshold value. P1 is fixed or is calculated as a fraction of the operating-parameter setpoint value and/or a pump parameter correlated therewith.

Abstract: An operational control device is disclosed for a positive-displacement pump having a motor, means for actuating the motor, state sensor means for detecting an actual operating parameter (e.g., pressure) of the pump, and operating mode means for controlling an operating mode of the pump. A first actuating mode of the operating mode means is set by the actuating means below a first operating-parameter threshold value (P1). This mode brings about a constantly rising pump pressure in the direction of an operating-parameter setpoint value (Pset) in a variable manner, which is dependent on a detected change in the operating parameter over a predefined time interval. A second actuating mode is set as normal operation to the operating-parameter setpoint value by the actuating means above the first operating-parameter threshold value. P1 is fixed or is calculated as a fraction of the operating-parameter setpoint value and/or a pump parameter correlated therewith.

Abstract: The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (YS) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (YS).

Abstract: An operational control device is disclosed for a positive-displacement pump having a motor, means for actuating the motor, state sensor means for detecting an actual operating parameter (e.g., pressure) of the pump, and operating mode means for controlling an operating mode of the pump. A first actuating mode of the operating mode means is set by the actuating means below a first operating-parameter threshold value (P1). This mode brings about a constantly rising pump pressure in the direction of an operating-parameter setpoint value (Pset) in a variable manner, which is dependent on a detected change in the operating parameter over a predefined time interval. A second actuating mode is set as normal operation to the operating-parameter setpoint value by the actuating means above the first operating-parameter threshold value. P1 is fixed or is calculated as a fraction of the operating-parameter setpoint value and/or a pump parameter correlated therewith.

Abstract: A double-flow centrifugal pump is disclosed, in which, using an impeller, a fluid can be suctioned from two axial sides from a negative pressure area and can be delivered in the radial direction into a positive pressure area. The negative pressure area is sealed off with respect to the positive pressure area by at least one stationary pump component, for example the pump housing and/or an insert part. According to the invention, sealing gaps are formed as axial gaps arranged axially between the impeller and the pump component and extending in the circumferential direction and in the radial direction, wherein the gap width(s) of said axial gaps is less than the radial spacing (a) of the impeller from all the components arranged with a radial spacing from the impeller.