Abstract: A terminal box for a centrifugal pump is releasably connectable to an electronic extension module by a locking element. A pluggable electric interface extends through an opening from an underside of the base plate into the terminal box to electrically connect the pump control for establishing a data link. The locking element is slidable in the cavity and is movable manually from a first position to a second position and by a tool from this second position to this first position. It also has on a first side a resilient latch engaging with either a first recess of the terminal box and holding the locking element in the first position, or a second recess of the terminal box holding the locking element in the second position. Thus the locking element frees the module for plugging-in in the first position, and arrests the module in the second position.

Abstract: The invention relates to a method for controlling at least one first circulation pump (17b, 17c) of a heating or cooling system (1) having a primary circuit (2, 2a) and a secondary circuit (4, 30a) coupled therewith at a transfer point (3, 29). The first circulation pump (17, 17b, 17c, 17b?) conveys a heating or cooling medium in the primary circuit (2, 2a), and in the second secondary circuit (4, 30a), at least one second circulation pump (12, 17d) is located that conveys a heating or cooling medium in at least one partial area of the secondary circuit (4, 30a). The volume flow rate (formula I) of the first circulation pump (17, 17b, 17c, 17b?) is controlled in functional dependence on the volume flow rate (formula II) of the secondary circuit (4, 30) behind the transfer point (3, 29). In this way, a demand based, and thus an energy-efficient control of the primary-side circulation pump is achieved.

Abstract: The present invention relates to a method of operating an electric motor-driven centrifugal pump (3) in a hydraulic system (4) having at least one self-controlled load, where a gradient (dQakt/dt) of the volumetric flow rate (Qakt) of the centrifugal pump (3) is determined and the current set-point delivery head (Hsoll) of the centrifugal pump (3) is calculated from a mathematical operation on the gradient (dQakt/dt) weighted with a gain factor (K) and the last specified set-point delivery head (Hsoll,alt). The operation describes a positive feedback between the set-point delivery head (Hsoll) and the volumetric flow rate (Qakt). The gain factor (K) is determined from a calculation instruction that is modified dynamically during operation of the centrifugal pump (3) taking into consideration the current operating point of the centrifugal pump (3) and taking into consideration a current and/or at least one past state of the hydraulic system (4).

Abstract: The invention relates to a method of operating a pressurized wastewater-drainage system (1) having interconnected line sections (SA1 . . . SA9) for conducting wastewater to a transfer station (10) and a plurality of pump stations (2) connected to the line sections (SA1 . . . SA9) for collecting the wastewater, wherein at least a portion of the pump stations (2) transmits at least status information indicating its respective pump standby status to a central controller (3), wherein a group is formed from the set of pump stations (2) that are in pump standby in relation to one of the line sections (SA1 . . . SA9) such that the number of pump stations (2) of the group corresponds at least to a minimum number (p_min) of pump stations (2) associated with this line section (SA1 . . . SA9), and the pump station (2) or pump stations (2) of the group are then activated simultaneously by the central controller (3).

Abstract: The invention relates to a method of determining a first hydraulic variable (Q) of a pump assembly (1) operated at a predefinable rotation speed (n0) from a mechanical or electrical variable (Mactual, Pel, nactual) by evaluating a correlation between the hydraulic variable (Q) with the mechanical or electrical variable (Mactual, Pel, nactual). A control parameter (Msetpoint, nsetpoint) of the pump assembly (1) is acted on by a periodic excitation signal (fA,n (t), fA,H(t)) having a predetermined frequency (f) such that a second hydraulic variable (H, ?p) is modulated. The instantaneous value of the first hydraulic variable (Q) is determined from the mechanical or electrical variable (Mactual (t), Pel (t), nactual (t)) as a system response (X(t)) to the excitation signal (fA,n (t), fA,H(t)), using the correlation. The invention further relates to a pump control system and a pump assembly that are configured for carrying out the method.

Abstract: An eccentric screw pump comprising an outer part (2) and an inner part (3) therein, one of the parts (2, 3) being driven rotatably and the other part (2, 3) being able to move eccentrically relative to the other part (3, 2). The screwthreads (5a, 5b) of the outer part (2) extend angularly over less than an entire helix along the axial length (L) of the part, so that during operation pumping chambers that are open to both ends are created, through which sudden pressure relief takes place.

Abstract: The invention relates to a centrifugal pump, in particular a waste water submersible pump having an impeller (1), of which the end face facing the pump intake opening is open and only the end face of the impeller facing away from the intake opening (8) is covered by a circular coaxial impeller hub (2), on which the curved vanes (3, 4) are fastened, and in particular molded on, wherein the base plate (7) having the intake opening (8) facing the impeller (1) or at least one segment (7a) of the base plate is mounted so as to be movable against spring pressure (20) in such a way that the distance thereof from the impeller (1) and thus from the impeller vanes (3, 4) changes.

Abstract: The invention relates to a centrifugal pump, in particular a waste water submersible pump having an impeller (1), of which the end face facing the pump intake opening is open and only the end face of the impeller facing away from the intake opening (8) is covered by a circular coaxial impeller hub (2), on which the curved vanes (3, 4) are fastened, and in particular moulded on, wherein the base plate (7) having the intake opening (8) facing the impeller (1) or at least one segment (7a) of the base plate is mounted so as to be movable against spring pressure (20) in such a way that the distance thereof from the impeller (1) and thus from the impeller vanes (3, 4) changes.

Abstract: The invention relates to a system and to a method for regulating a flow of liquid in a line, with a pump delivering the liquid to the consumer, tank or process. In particular, the invention relates to a sewage disposal system for public disposal of sewage, with a sewage pipe network comprising a plurality of sewage lines, and with at least one motor-driven pump delivering sewage through the sewage lines to a settling tank, to a service water support system for public supply of water, with a water supply pipe network comprising a plurality of water supply lines and with at least one motor-driven pump delivering service water through the water supply lines to a consumer, and to a liquid delivery system for providing a chemical liquid in a process, with a liquid pipe network comprising a plurality of pipelines and with at least one motor-driven pump delivering the chemical liquid into the process.