A specially adapted screen changer for use on PET polymerization lines has helped KÖKSAN PET Packaging Industry Company extend the life of melt filters and improve the quality of preforms and bottles produced in subsequent operations.
KÖKSAN, a comprehensive producer of resins and various PET packaging products, has been using Nordson Corporation's standard BKG® POLY screen changer and its huge filtration area is designed for high-volume polymerization with eight Filter chambers, each containing a flat screen supported by a perforated plate. In a retrofit to KÖKSAN, Nordson replaced the screens and perforated plates with newly designed perforated plates, each supporting multiple Filtration of the wick This results in a tenfold increase in filtration area and an increase in filtration accuracy compared to flat screens.
The result is increased efficiency, significantly longer filter life, minimized dark spots and gels, and drastically reduced pressure drop across the polymer for lower shear stresses.
'With Nordson's POLY candlestick filter design, the incremental pressure across the filter can be reduced even at 120% production, extending the life of polymer pumps and their mechanical seals.' KÖKSAN's PET Resin Division Peter Thomas V, Managing Director, said: "This helps the melt pump to last for many years without interruption."
Nordson's custom reinforced BKG POLY screen changer also enables KÖKSAN to tighter control over the quality of virgin resin used in the company's food and beverage containers, notes Mr. Thomas. "This is especially important for the production of preforms, where the gel and mold Stress can cause defects and waste of parts.
Nordson's filter wick is a tubular part that is installed parallel to the direction of the melt flow. The melt enters the filter candle through the filter pack and is directed to the inner core of the filter candle and then appears downstream. Used to increase the area of the filter without increasing the size of the machine or affecting the throughput This design, in turn, reduces the pressure drop and residence time of the melt Filter wicks come in a variety of sizes and filtration accuracies.
Screen changers with filter wicks can still be used with standard filters and perforated plates, providing another advantage: flat screens can be the most economical way to filter, either during start-up or after shutdown, The filter wick is used only when the specified material quality is reached during the process to continue further production, ensuring optimal product quality and extending filter life.
In the BKG POLY filtration system, there are four filtration chambers on each of the two plungers to divide the melt flow into eight flow paths, and when the pressure differential between the upstream and downstream sides of the filter element reaches a specified level, it will be emitted Replacing the signal from the filter element Although the two filter chambers are removed by one of the plungers during the filter element replacement, the melt flow continues uninterrupted through the other six chambers Therefore, when replacing the filter element The process can continue production without the need for any additional valves or devices.