Cooling towers dissipate both ambient and process heat in most large manufacturing facilities. These structures facilitate the transfer of unwanted energy (heat) from a transport liquid (usually water) to the atmosphere. Problems with efficient heat transfer, equipment protection and pathological risks to employees can most often be traced back to an issue with suspended solids. These solids can originate in the process, in the piping, from the atmosphere or from internal biological growth. Side-stream filtration is the most commonly used method of maintaining minimal suspended solids in a cooling system.
Side-stream filtration takes a portion of the flow from the system and filters it to remove suspended solids and then returns the clean water back to the system usually through the cooling tower reservoir or sump. This method maintains general control of suspended solids. It does not filter all the water going to the process. Historically, cooling systems have relied heavily on the two following established methods of suspended solids removal.
Cyclonic devices are highly efficient at removing high specific gravity solids, while granular media filtration generally is more effective at removing low specific gravity organic solids. Automatic self-cleaning screen filter technology provides a solid barrier to both organic and inorganic solids regardless of specific gravity and requires very little energy to operate. In addition they conserve coolant additives by using very little coolant liquid for the self-cleaning process. The unwanted loss of coolant can be completely eliminated by incorporating the cleaning cycle into the blow-down process of the cooling system.