The Vibra Screw Continuous Loss In Weight Feeder provides unparalleled versatility in handling a broad range of feeding requirements. Feed rate from 20 pounds to 24,000 pounds per hour can be accomplished with accuracies of plus or minus 1/4-1% on a minute-to-minute basis at 2 sigma. Control of the feeder is through a microprocessor-based controller equipped with one million counts of resolution and exclusive disturbance elimination technology. The continuous weighing feeding devices can include pan or tube feeders, screw feeders and belt feeders. Vibra Screw is the only manufacturer to offer a controlled vibration feeder design for weigh feeding, This means minimal loss of accuracy during the volumetric refill cycle and unprecedented accuracy in the gravimetric mode.



How does Loss In Weight Feeding Work?
A Loss In Weight feeding system includes a supply hopper or tank, a metering feeder or pump, a supporting scale system, and a microprocessor controller. The system electronically balances tare weight so the controller senses only the weight of the material in the supply hopper.

At time zero, the hopper is full (high weight), and the operator enters the set point or desired feed rate into the controller.

As time and discharge advance, the actual sensed "loss in weight" follows the decreasing scheduled weight ramp whose slope is a direct representation of the desired weight of delivered material per unit of time (set point). The controller makes frequent comparisons of sensed vs. desired rate and alters the feeder's output, keeping it at the set point.

Once the sensed weight reaches the hopper refill level (low weight), the controller locks the feed system into volumetric control. The hopper is recharged, and the loss in weight cycle repeats.

The controller rate disturbance mode protects against any outside weight disturbance that might cause an upset and provides the unique ability to manually load the hopper at any time without disturbing the feed process.