During storm events combined sewer networks receive many times more water than during dry weather. The receiving waste water treatment plant can not handle these huge amounts of flow. In order not to discharge every bit of excess water, retention volume in for of storm water tanks and CSO tanks is being added. After the storm event has passed the stored water is slowly channeled back into the sewer network and therefore to the treatment plant. Ideally the flow to the treatment plant does not exceed a set maximum at any time.
Flow regulators are installed in order to realise this task. With varying water levels they regulate the flow to the waste water treatment plant and keep constant at the max.
The flow regulators that are available today can be grouped into electro-mechanically operated and self powered, external energy free systems. All systems operate nearly by the same principle. A constantly adjusted flow resisting mechanism regulates the flow either directly or indirectly proportional to a control water level.
Further we separate open and closed loop control systems. A closed loop flow regulator always has the advantage that it is based on a closed loop between the result "regulated flow" and the respective control parameter. This ensures constant self adjusment of the control mechanism. Uncontrolled flow regulators are the simplest. However, they do not adjust to varying flows and discharge a somewhat varying flow amount.
The following table shows an overview over the different flow regulators:
Type of regulator | Regulating principle | Self powered | Closed/ Open looped control | Pros/ Cons |
controlled gate | Water level msrmt. Upstream with US-sensor | no | open loop | automated blockage release |
controlled gate | Q-msrmt. w/ MFM | no | closed loop | exact control/ rel. high price and space requirement |
Vortex | turbulent flow | yes | ungesteuert | step necessary |
Pipe regulator | wall friction | yes | ungesteuert | low cost |
fixed throttle | reduction of cross section | yes | ungesteuert | low cost, does not need much space |
SGS Aqua Technologies GmbH currently offers flow regulators with open loop control gate "Aqua-Mat- H" and a closed loop control system w/ regulating gate "Aqua-Mat- Q".
