What Is a Circle Feeder?
A circle feeder is a stock hopper type powder/pellets feeder with an integrated hopper and agitator blades to prevent bridging. The circle feeder was researched, developed, and manufactured by Yoshikawa Corporation.
It is also known as a circle hopper or table feeder.
Inside the hopper where the circle feeder is installed, the agitator blades rotate, dropping small amounts of powder material from the discharge port at the bottom of the hopper to the feed port of the screw feeder below.
The system has been very successful in preventing bridging and segregation of powder materials.
Applications of the Circle Feeder
Circle feeders are used for stable feeding of powder materials from hoppers that store powder materials.
They can handle a wide variety of difficult-to-discharge powder materials, especially those that are fibrous, sludge-like, flaky, lumpy, or bridging.
The circle feeder can provide a closed environment for feeding, and a single circle feeder can simultaneously discharge multiple locations.
Circle Feeder Principle
Circle feeders and table feeders are table-type powder feeders with a unique structure installed at the bottom of hoppers and silos.
At the bottom part, on a board, flat blades rotate to cut out the powder material to the outer circumference of the hopper or other cylinders.
The powder material brought to the outer circumferential part of the hopper is carried by the blades rotating around the circumference to the outlet.
The dish or vane rotates slowly and continuously in the lower part of the hopper to keep the powder material in motion at all times.
The raw material is fed through the outlet from which it is discharged on the table to the screw feeder below.
It is often used in combination with a twin screw feeder.
The method of adjusting the amount of powder material fed is to first change the rotation speed, then the number of scrappers, and finally the gap between the scrappers.
As for the merits of circle feeders, first, it is difficult to apply force to the powder material, and stable feeding of powder material is possible.
Second, the feed port can be wide and easily sealed, and multiple discharge ports can be installed.
On the other hand, the demerits of the circle feeder are that it is difficult to make it compact, it is not suitable for powders with poor flowability, and it is difficult to adjust the powder and improve feeding accuracy.