Nordson BKG, as part of the Nordson Corporation Polymer Processing Systems product offering, is a world-leading product line of underwater and water-ring pelletizing systems and pellet dryers. Turnkey complete lines with throughputs of 2 – 35,000 kg/h are available. All materials which have thermoplastic features may be reliably processed. Pelletizing of exigent technical plastics and production of micro pellets are possible.
Nordson is also a market leader in the field of melt filtration and gear pumps. The product portfolio consists of BKG® screen changers, BKG® melt pumps and BKG® polymer valves and offers clear advantages, from the standard execution to the custom-made, individual special solution. Innovative concepts of BKG screen changers allow for a process-, pressure- and volume constant filtration.
Nordson will present parts of it BKG® product line, consisting of
The BKG® HiCon™ R-Type 250 is a contiuous screen changer that can be used for medium to highly contaminated plastic melt and polymers from the family of olefins and styrenes in recycling applications.
• Minimal melt loss
• Constant melt pressure behind the filter
• No outlet side; minimum pressure required
• Low operating costs through long service life and
• No edge flow around the strainer tube
As a high-end polymer melt pumps manufacturer, Nordson helps customers optimize their processes so extrusion and pelletizing lines achieve the highest possible quality and throughput. The BKG® BlueFlow™gear pump product line covers masterbatch pumps, melt pumps for sensitive plastics, high-pressure gear pumps, low-viscosity pumps and pump control panels. Our gear pumps are manufactured to provide optimal efficiency whether you’re engaged in extrusion, compounding or polymerization.
Nordson's BKG® pelletizing machines are not only suitable for thermoplastics but also for all materials which behave like thermoplastics.
BKG® Pelletizers Type AH and AHD offer automatic, hydraulic blade pressure regulation
• Throughput rates of 2 – 35,000 kg/hr (4 – 77,000 lb/hr)
• Superior and constant cutting quality for all viscosities
• Minimal operator intervention through automatic die plate grinding
• Optimized wear by fine adjustment of blade pressure regulation
A new-design pellet dryer for use with Nordson Corporation’s BKG® pelletizing systems meets the challenge posed by the steady growth in use of glass-filled and other abrasive materials by substantially reducing the time and cost associated with replacing “wear” parts.
The design reduces the number, complexity, and cost of the dryer components that are subject to abrasion and makes them more accessible to maintenance or replacement. While the new dryer has much the same overall appearance and footprint as a standard BKG dryer and provides the same throughput, there are substantial differences in the configuration of components subject to wear. The new design reduces production downtime by simplifying maintenance, making it possible for one person to carry out maintenance tasks.
A reduction in maintenance times by up to 70% can be realized. It is now possible to determine concrete maintenance intervals, so downtime becomes more plannable and less unexpected.
There are a number of design enhancements for reducing wear or simplifying maintenance:
New screen packs for BKG® screen changers from Nordson Corporation effectively withstand the pressures of extrusion, providing maximum filtration and optimum melt flow while ensuring a longer working life and greater reliability than low-end screen packs on the market. Nordson will introduce the screen packs at Fakuma 2018 (Booth A6-6109).
One key to the enhanced performance of the new screen packs is a robust multi-layer structure that prevents failures caused by the pressure differential—up to 200 bar—encountered during filtration. One such failure is “screen dimpling,” in which the mechanical stress forces screen layers into the holes of the breaker plate that supports the screen in the cavity. This distorts the screen, breaking the peripheral seal and causing contaminants to bypass the screen and become part of the end product.
Nordson precisely tailors the size of the screen pack to the dimensions of the cavity, eliminating the common problem of contaminant passing the screen pack at the edges. In addition, all screen pack components are ultrasonically pre-cleaned during manufacture to eliminate contamination from the oil and grease used in the weaving process.
“The new Nordson screen pack design maintains structural integrity while efficiently filtering out contaminants and ensuring optimal melt permeability,” said Christian Schroeder, global product manager for melt delivery systems. “As a result, our screen pack yields more output between screen changes than screen packs offered as low-cost alternatives, increasing the productivity of the extrusion line and enhancing profitability.”
Depending on customer requirements, Nordson supplies the screen packs with different layer combinations. One common structure, for example, has four layers, including two coarse square-weave layers that serve as the outer components and a finer internal square-weave layer. These provide support and drainage functions and withstand high tensile forces. The fourth layer is an optimized Dutch weave wire mesh that serves as the fine filtration component. The small geometric pore size of the Dutch weave layer ensures high permeability. Filtration takes place crosswise with respect to the direction of melt flow, enabling dirt particles to be separated from the melt efficiently.
“A key factor for efficient filtration is permeability,” said Stefan Woestmann, application engineer. “The Nordson screen pack provides the optimum ratio of solid material and free volume, so that the polymer melt can use as many flow paths as possible to make its way through the filtration medium. In processes with low-end screens, which are not flow-optimized in this way, polymer melt builds up and causes a significant increase in pressure. This leads to premature and costly screen changes and endangers the quality of the end product. If the polymer flow is not uniform, the end product cannot be either.”
New-design BKG® HiCut™ cutter hubs and blades for Nordson's BKG® underwater pelletizers increase throughput, improve transportation of pellets from the cutting area, simplify cutter assembly, and provide new options for reducing wear to die plates and blades.
In an underwater pelletizer, the cutter hub and blade assembly produces pellets from polymer as it exits the holes in the die by rotating rapidly against the die face, with blades mounted at angles to the face of either 45 degrees (“angled”) or 90 degrees (“straight”). The new design increases throughput by accommodating up to 100% more angled blades per hub (36 instead of 18) or 54% more straight blades (40 instead of 26). As an alternative to increased throughput, the operator can reduce pelletizer RPM, maintaining standard throughput while reducing wear to die plate and blades.
Nordson carried out the redesign using the same metal as in the standard hubs and blades but employing a casting process rather than machining the metal. Besides making possible an increase in the maximum number of blades, our new manufacturing method has enabled us to increase the space between the blades, reduce the volume of the cutter hub assembly, and use countersunk fasteners for mounting the blades to the hub. As a result, there is improved transportation of the pellets, which enhances efficiency, improves pellet formation, and is particularly beneficial for producing micropellets [pellets with diameters less than 1 mm].
The redesign also makes it possible for the first time to use the same hub for accommodating either angled or straight blades, providing new versatility for users who run multiple materials.
“The new-design hub and blades can be used on any Nordson BKG underwater pelletizer with throughputs from 1,000 all the way to 35,000 kilograms per hour,” said Mr. Cowart. “While it is too early to quantify the range of throughput increases that the redesign makes possible, we do expect that the new cutter assembly will enhance productivity for our customers or in some cases even extend the applicability of smaller pelletizers.”