While Plastrac, a US-based manufacturer of blending systems, has been field testing its ergonomic ColorStream blending system, the US Patent Office has awarded the new unit patent approval.
Plastrac
Plastrac’s patented ColorStream blender
Plastrac is thus ready to roll out the new blender, which began life as a customer service request by a major cable and wire manufacturer to eliminate the need for employees to climb ladders or stairs to clean and change out additive hoppers that are mounted high above the floor.
Plastrac President Ken Bullivant explained: “Our response was to develop an entirely new approach to the industry’s traditional blending methods. We successfully decoupled dosing and feed from the main resin, moving blending to the plant floor and streaming colours and other additives to the feed throat of injection moulding machines and extruders to mix synchronously with virgin resin in real time.”
Colour changes and minimal maintenance occur on the plant floor. The cart can also be moved easily to ensure unhindered access to injection moulding machines and extruders when their maintenance is due. ColorStream’s low pressure transport air ensures there is nothing to clog and very little to clean.
ColorStream’s cart can support, up to four additive feeders with the small footprint as a cart with one feeder, arranged radially around a collecting funnel for discharge of the additives into a vertically mounted, custom-made venturi that discharges downward into a transport hose.
Its blowers operate continuously for years, according to a press release, and deliver clean air because there are no contacting parts requiring lubrication. The venturi and transport hose are small enough to deliver sufficient air velocity to keep transported granules entrained in the air stream.
At the upper end of the system, a compact but sturdy baffle box mounts to the feed throat of the plastics processing machine. The top flange of this box typically supports the customer’s central loader receiver and buffer hopper, which supply virgin material to the process. A cyclone-type receiver inside the baffle box separates the additives from the transport air, which is routed out of the baffle box laterally. A metal screen between the cyclone and the exhaust duct guarantees that stray additive granules cannot escape with exhaust air.
ColorStream works with all injection moulding, extrusion, and blow moulding machines and with all virgin resins, including PET. Visitors to Plastrac’s K show booth (Hall 10, Stand A01) will be able to see it in action.