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VIBRATORY CONVEYOR FEEDERS
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Adapted geometry to match the product by EPA Dosiertechnik GmbH, Germany
ince antiquity, the Archimedean screw has been used for conveyor tasks. In the modern bulk material industry, conveying and metering screws have become indispensable, although they have some disadvantages. By design, the material to be transported is compressed or squeezed, there are rotating parts in the product stream, which make cleaning difficult, and the sealing of the drive shaft is always a weak point with regard to product contamination. In many cases, high friction between the screw and the trough wall impairs the product, in addition, screw machines operate in a narrow performance range of only approximately 1:10. Nevertheless, screw conveyors cannot be replaced in many applications, but with just as many, it is also possible with vibrating conveyors (feeders).
54 | August 2019 - Milling and Grain
Technical principles of vibratory feeders
Oscillating conveyor drives are magnetically or pneumatically driven two-mass vibration systems with a drive base (A - the larger mass), a conveyor table with mounted conveyor trough and gutter assignment (B – use-mass) and leaf spring elements (C - they connect the utility Mass with the drive base) (See Figure One). The product on the channel is accelerated by the oscillation with defined frequency and amplitude (Fa) and travels a small distance on the channel, which correlates directly proportional to the stroke of the channel. Due to the force of gravity (Fg), the product remains after acceleration over the distance (stroke) on the channel (Fh), by renewed acceleration with the drive frequency, the process is repeated (See Figure 2). The product is thus transported with the drive frequency and the stroke of the channel, without being mechanically stressed. In the