Loss-in-weight feeders are genuine all-rounders and have replaced many volumetric and gravimetric feeders since the 1980s.
Loss-in-weight feeders can be used for both small to medium feeding ranges. They work with extreme precision under optimum ambient conditions. They are very flexible and can handle bulk solids, liquids and even poorly flowing products. They are used in many continuous processes such as feeding extruders requiring a high level of short-term feeding consistency. They are also used in the food industry and in laboratories by means of appropriate storage containers and adapted feeding devices. The design varies from compact constructions to modular concepts depending on usage.
Principle: When the material is fed through the feeder, the weight of the system decreases. Controlling the loss-in-weight feeder changes the feed rate and as a result the speed of weight loss matches the desired feed rate. Loss-in-weight feeder controls continuously check whether the material is flowing.
All components and/or any product they contain is continuously weighed during operation: the feeder, the hopper and the material.
Gravimetric feeders, for instance, have slight fluctuations in their feed rates. These fluctuations occur in the filling capacity of the augers and in the bulk density of the material. These are compensated for by adapting the auger speed in order to ensure the product is dispensed evenly.
Loss-in weight feeders for bulk materials consist of: storage tanks, controlled feeding devices such as augers, chutes, pumps as well as scales or load cells, loss-in-weight controllers or rather loss-in-weight feeder controllers. Optional: e.g. agitators to improve the quality of the bulk material.
The Schenck Process loss-in-weight feeders have, for instance, been optimised for the compound industry. Flexible installation options, different feeder sizes and hopper sizes are adapted to each available space. Vertical container walls mean that virtually every millimetre is used to the max and impact positively on the bulk material flow. Thanks to the off-centre auger arrangement, up to eight feeders can be positioned next to each other. The drive and auger setup can still be customised during assembly.
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