Abstract: Method for determining the UV transmittance of water in a UV disinfection plant, through which water flows, wherein the UV disinfection plant has a plurality of radiator arrangements, each with a UV radiation source, a sleeve tube which surrounds the UV radiation source and which has an end face at an open end, and with a UV-C sensor which detects the UV radiation emerging from the sleeve tube without the influence of the water, and with at least one further UV sensor which is arranged at a distance from the sleeve tubes of the radiator arrangements, wherein the method includes the following steps: measuring the UV radiant power emerging from the sleeve tube; measuring an amount of the transmitted radiant power by the further UV sensor; and determining the transmittance of the water by an amount of the emerged radiant power and of the transmitted radiant power.

Abstract: A method for controlling a pump arrangement upon clogging. The arrangement includes a pump and a control unit. The pump includes a motor, and the control unit drives the motor. The motor during operation is associated with an operational parameter from which the motor torque may be derived. The operational parameter has a normal value PN during normal operation of the motor in a first direction. The method includes the steps of driving the motor in a first direction by the control unit, stopping the motor if a real value P of the operational parameter exceeds a predetermined clogging limit PI, driving the motor in an opposite second direction a predetermined flushing time TR by the control unit, and stopping the motor if the absolute value of the real value P of the operational parameter during the flushing time TR exceeds the absolute value of a first unfastening limit PL1.

Abstract: A plant and method for controlling such a plant suitable for treatment of waste water. The plant includes a basin, a flow generating machine adapted to generate a liquid flow in the basin, equipment in the basin that effects the momentum of the liquid flow, and a control unit. The method includes the steps of: storing a predetermined relationship between the operational speed N of the flow generating machine and an operational parameter P from which the torque M of the flow generating machine may be derived, determining the operational speed N, determining a set value of the operational parameter P of the flow generating machine, determining a real value of the operational parameter P of the flow generating machine, and adjusting the operational speed N if the real value of the operational parameter P is different than the set value of the operational parameter P.

Abstract: A pump station arrangement and a method for turning off a pump configured for pumping liquid via a conduit. The pump, before being turned off, being driven at an operational frequency (FN) by a control unit. The method is characterized by the steps of, ramping down the frequency of the pump due to a turn off instruction, the terminal frequency of the ramping down being equal to the operational frequency (FN) of the pump minus at least 10 Hz and the ramping down time being at least a reflection time (TR) for the conduit in question, and the terminal frequency of the ramping down not being less than 10 Hz, and stopping the pump after the ramping down.

Abstract: A guide rail assembly for a submersible machine as well as a guide rail holder for such a guide rail assembly is described herein. The guide rail holder includes a radially extending support body and an axially extending post, which is rigidly connected to the support body and which is adapted to be inserted into an end of the guide rail. An engagement head is connected to the post at a distance from the support body and has a greater radial extension than the post. The engagement head includes a radially expandable member that is adapted to be reversibly manipulated between an active state, in which the expandable member is in engagement with the guide rail, and an inactive state, in which the expandable member is disengaged from the guide rail.

Abstract: Propeller pump for pumping liquid, including: an axially extending tubular pump housing having an inner surface, an axially extending pump core having an envelope surface, at least one axial portion of the pump core enclosed in the pump housing. The pump core includes a propeller having a hub and at least one blade, and at least one guide vane that includes an upstream leading edge and a downstream trailing edge, and that in the circumferential direction includes a pressure side and a suction side. The guide vane extends between the inner surface of the pump housing and the envelope surface of the pump core. At the leading edge of the guide vane a connection angle between the suction side of the guide vane and the envelope surface of the pump core is larger than 90 degrees.