FUNCTION
The CSO screen RSW-K, fitted vertically between the discharge culvert and the relief sewer, reliably retains all visible solids > 4 mm when the excess water flows through horizontally.  It is mounted on the owner's prepared concrete sill.  The height of the sill depends on the hydraulic survey.  Type RSW-K is a combination of Type RSW and a controlled weir wicket, but the basic functions of the CSO screen are identical.  The relief height can now be controlled on Type RSW-K with a control function.  The weir wicket is controlled by two hydraulic cylinders.  The aim of the control function is to discharge as little contaminated rainwater as possible into the relief sewer.  This works as follows:  In basic position, the weir wicket is closed, i.e. no effluent or waste water can flow into the relief sewer.  If the water level at the inlet end has reached a predetermined height, the weir wicket starts to open.  Level probe which allows various level heights to be measured generates the signal.  An optimum position of the weir wicket then corresponds to each signal.  This achieves minimum discharge into the relief sewer.  Cleaning is also performed by the cleaning carriage analogously.

DESIGN
The design of the RSW-K is identical to that of the RSW in the screen area.  The same components are used.  A rugged moving weir is attached by means of hinges and tight metal side panels in place of the static retaining panel.  An all-round seal on the carrier frame of the CSO screen ensures tightness at three sides when the weir wicket is closed.  When open, the weir wicket seals against the lateral guides.  The weir wicket is driven by two control cylinders which move synchronously owing to the incorporate displacement measuring systems.  The anchoring system of the control cylinders is integrated in the frame structure.  The structure itself is thus not loaded additionally.
When the control cylinders are fully extended, the hydraulically calculated maximum angle of the weir wicket is reached.  This prevents overloading of the screen surface owing to an excessively low relief height.

 
     
No wastewater can flow to the relief sewer until the water level reaches a pre-determined height, at which point the weir opens just enough to maintain the upstream water level.  Water level can now be controlled by the dynamic opening and closing of the weir to discharge as little wastewater as possible to the relief sewer.