Feeders with different screw profiles
Kubota Brabender Technologie has been developing feeders for the food, plastics and pharmaceutical industries for more than 60 years, and provides a broad range of equipment. “Screw feeders are one possible solution for ingredients with poor flow properties as well as for sticky powdered ingredients such as flour”, says Guido Obler, food specialist at Kubota Brabender Technologie. Spiral, blade or twin concave screws are used, depending on product characteristics. “Special screws with progressive pitches ensure a particularly gentle feeding process for sensitive products.”
Feeders with agitators, constant screw fill levels
A constant screw fill level is important for accurate, continuous feeding. To ensure that the screw does not cause bridging in the feeder, agitators can be used to keep the bulk ingredient in motion and deliver consistent mass flow. Type DSR (single-screw) or DDSR (twin-screw) screw feeders each feature an agitator with a horizontal shaft that ensures that the screw is evenly filled along the entire length of the screw trough.
Special Type DVT vibratory tray feeders are suitable for particularly delicate ingredients such as extrudates, nuts or freeze-dried products, which could be damaged by an agitator. Guido Obler explains the feeding principle: “Vibration causes the ingredient to be discharged freely from the weighing hopper onto the tray, and vibration amplitude controls the flow rate.”
FlexWall®- feeders with massaging paddles: agitators not needed
Another option that is exclusive to Kubota Brabender Technologie is the patented FlexWall® feeder with massage paddles. “The flexible polyurethane hopper is agitated using external massage paddles, making agitators in the product space unnecessary.” The feeder’s trapezoidal shape generates mass flow into the feed screw. It also provides a key plant layout benefit, the expert explains. “Given its design, several FlexWall ® feeders can be arranged in a circle around a central feed point to save space.” All components that come into contact with the ingredient can simply be detached from the base in a few quick steps and then easily cleaned.
Like all Kubota Brabender feeders, the FlexWall® is available in both volumetric and gravimetric versions. Loss-in-weight feeders offer maximum precision to control feed rates and to monitor manufacturing processes. An important process feature of operating continuous loss-in-weight feeders is rapid refilling. As volumetric feeding occurs during the refill process, it is important to keep refilling as short as possible. To do this, the refill rate should exceed the feed rate by at least a factor of ten. However, a smart, self-learning control system can maintain high feeder accuracy, as in the gravimetric phase, if filling cycles are repeatable.
Versatile and fast: weigh-belt feeders
Weight-belt feeders are also ideal for continuous processes. Its throughput rate is the mathematical product of belt occupancy and belt speed. They are great for high feed rates, as they remove the ingredient directly from the storage hoppers. “Kubota Brabender Technologie’s weight-belt feeders are commonly used in the manufacturing of granola bars, for example, where they are used to feed cereal flakes or nuts”, as Guido Obler explains from experience.