Automatic backwashing systems reverse the flow and backwash the shell-and-tube or plate-and-frame exchangers. The reversal of the flow direction and the increase of the (local) flow velocity fight have the following effects:
An Eqobrush reversal valve can simply be installed on the supply and return pipes. It periodically reverses the flow through the exchanger for a short time and without interrupting its operation. The flow returns to normal direction after a short while (less than a minute). Periodic back-washing by means of an automatic back-washing system dislodges accumulated solids and allows substantially longer intervals between interruptions of operation for cleaning.
Caused by: Algae spores, small eggs, larvae. They end up in the heat exchanger and can stick and settle in the low flow areas.
Clogging by debris
Caused by: Algae, seaweed, mud, leaves. If a strainer is not used, they will clog up the inlet side of the heat exchanger. Even with a strainer in place, this may happen. Also, the strainer needs to be equipped with automated cleaning which is more expensive (investment and maintenance) than a backflush valve.
Fine particles such as silt, sand, mud, and other suspended solids enter the plate heat exchangers and accumulate between the plates, which causes plugging and promotes scaling and pitting.
Maintenance and gasket life span
With backflushing, fewer interruptions for cleaning are required. The cleaning interruptions (disassembly and reassembly of the plates) are the greatest burden on the lifespan of the gaskets. Gasket replacement is expensive, and these costs can be considerably reduced.