The Optigon System from Nordson BKG, Roswell, Ga., is said to use more than 90% less energy than standard water filtration systems and cuts overall pelletizer power usage by up to 17%.
The Optigon water filtration system eliminates need for a separate fines-removal sieve, which in standard systems requires a secondary, dedicated water pump. Instead, all filtration is provided by a Polygon drum filter, whose 70-micron screens are finer than the 150-micron screens used in standard systems. Driven by a small motor, the drum rotates within the water that is circulated throughout the pelletizing system by the main process water pump. The filtration system is designed so that dirt and fines stay confined inside the drum until they are evacuated into a collecting basin outside the tank.
By eliminating the secondary pump, the Optigon water filtration system uses only 1440 kW/yr (measured at 8000 hr), as opposed to 44,000 kW and 98,480 kW for the company’s Opti-Line and Poly-Line systems, respectively. Since water filtration typically accounts for 10 to 17% of the energy consumption in underwater pelletizing, the energy efficiency of the Optigon system means that overall consumption is cut by nearly that much.
Other energy-saving measures developed by Nordson BKG are two that are available to customers as optional features: 1) complete insulation of the water system to prevent loss of heat to the workplace and serve as touch-protection for workers; and 2) insulation of the die plate heating flanges, ensuring a uniform temperature profile in the flow channels and retention of heat in the die plate, with energy savings of 30% compared with standard die plates