MID Flow Control Type SDS

The discharge from the restraint system is measured with a magnetic-inductive flow meter (MID) for partially and fully filled pipes, so that dry weather runoff and rainy weather runoff can be registered. In dry weather, the control slide is fully open, so that an unimpeded flow through the controlled system is guaranteed. If the discharge volume in rainy weather exceeds the preset setpoint, the control is activated.

The electric control drive is activated and closes the control slide until the slide plate position belonging to the current flow rate has been reached. The electronic controller constantly compares the measured flow rate with the setpoint. By changing the slide plate position upwards or downwards, the throttle cross section behind the measuring section is always adjusted to such an extent that the set throttle discharge quantity is exactly maintained. The control process continues until the backflow in the retention area has been removed and the flow rate is below the setpoint. If this is the case, the control slide opens automatically and creates a full discharge cross-section.

If a blockage occurs during the control process, this inevitably reduces the flow rate. This in turn leads to an automatic raising of the slide plate – if necessary – until the control slide is fully opened.

After the throttle cross-section is flushed out and the flow rate increases spontaneously, the control slide moves back into its control position. In the case of a backflow, the flow rate drops due to the counter pressure. The flow meter records the decreasing discharge volume and opens the control slide until the set target discharge has been reached again.