Thermo
Electron Corporation's Loss-In-Weight Feeders maintain quality,
weighing accuracy, reduce material waste and improve blend
consistency for increased profits.
The accurate
feeding of a dry bulk material is often critical to maintaining
product quality. A feeder that weighs accurately and reliably
can reduce material waste, improve blend consistency, and
increase profits. Thermo Electron Corporation?s Loss-in-Weight
systems accurately control the flow of powders, pellets, flakes
or granules to critical processes.
Theory
of Operation
The continuous
Loss-in-Weight principle involves weighing the entire feeding
system (hopper, feeder and bulk materials) by means of a static
type scale system and controlling the discharge feed rate
of the bulk material, by means of a variable speed motor.
Material
is discharged from the system (via screw or vibratory tube
or tray) with the measured ?loss in weight? per unit time
(dv/dt) compared to the desired (set) feed rate. The
difference between the actual (measured) rate and the desired
(set) rate produce a corrective action by the feed rate controller
(Micro-Tech 2104), which automatically adjusts the feeder
speed, thus maintaining accurate feed rates with no process
lag.
Advantages
of Loss-in-Weight Feeding
- Handles
hot, floodable and difficult materials
- Unaffected
by dust and material accumulation
- Well
suited for low feed rate applications
- Entire
system is weighed. No errors from belt tensioning or tracking.
- No
transportation lag time exists, which assures precision
second-to-second accuracy.
- Feed
accuracy can always be checked during normal operation,
without the need for sampling.
