The purpose of these devices is to maintain a constant rate of filtration. An important component of the regulation system is the Venturi meter which measures the bed resistance or loss of head. When the resistance builds up, the operator opens the regulating valve so as to maintain a steady rate of filtration. When the loss of head exceeds 1.3 meter it is uneconomical to run the filter.
The filter is equipped with certain valves and devices which are incorporated in the outlet pipe system. |