FLOW LOGGER -
The main function of flow meters in the pressurised sewer
network is to measure the flow of sewage, usually from
pumping stations to either another pumping station, or
normally, the wastewater treatment works. They are basically
there to monitor the output of a pumping station.
As they are normally at pumping stations they usually have a link to the company’s telemetry system for communication purposes and are linked to power source. There are options for flow meters to work from batteries and use the mobile phone network for communications.
There are numerous benefits associated around the use of flow meters at pumping stations, including:
Monitoring pump efficiency;
Ensuring compliance with pass forward flows;
Monitoring flow readings in the network to detect potential network blockages;
Increase situational awareness where alerts or alarms are raised to enable an assessment over whether the alarm warrants an operational visit.
Typically, electro-magnetic flow meters are installed for flow monitoring for pressurised systems and there are some system requirements:
Good installation of electro-magnetic flow meters require an upstream and downstream space away from interference to work effectively. The space that is available downstream of a pump needs to be approximately 15 pipe dimensions to avoid interference from the pumps themselves. Downstream of the flow meter approximately 5 pipe diameters are required.
Power and telemetry are preferable but are not essential as some of the technologies can run off batteries and communicate via the mobile phone network, although this will increase operational costs with replacement batteries.
Electro-magnetic flow meters also require a full pipe at all times to work correctly (although a partial flow electro-magnetic flow meter is available at times.
There are alternative technologies such as Time of Flight Measurement, which has similar requirements.