How to improve accuracy on your macro and midi ingredient weighing systems
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by Benny Simonsen, Working Board Member, Jesma Vejeteknik A/S, Denmark he production of terrestrial and aqua feeds is a typical example of a discontinuous production process that employs a process of batch and semicontinuous operations. The bottle neck in many feed mills is the macro- and midi- dosing cycle. This bottleneck can be avoided by employing a Jesma solution where you, at the same time, also optimise your batching operation as well as the dosing accuracy.
What is included in the typical feed mill?
At the centre of a typical feed mill process, you will find the batching, dosing, weighing and mixing processes. A batching system is typically based on an operating average of approximately 10-12 batches-per-hour, corresponding to between five-to-six minutes per batch. When calculating the total batching time, the emptying of scales and conveying systems need to be included.
The typical feed mill includes one macro, midi, micro and nano scale each (See Figure 1).
Calculating total batching time
• When calculating the total batching time per cycle it is necessary to include the following operations: • Dosing (each ingredient is dosed one by one) • Stability of scale between each dosing • Emptying of scale and transfer of ingredients to next process step • Rest emptying of conveying line* * To avoid cross contamination between different batches and production orders the scale and conveying lines should be cleaned by running the chain conveyors and bucket elevators for some time after the last product has discharged from the hopper scales. As mentioned previously, a typical feed mill batching cycle is between five-to-six minutes and the bottleneck in many feed mills are the macro and midi dosing cycles. To eliminate this bottleneck, Jesma has developed solutions in which the batching operation, as well as, the dosing accuracy can be optimised.
Figure 1: Typical Feed Mill Batching System with post grinding system
Macro Bins
Midi Bins
Single Hopper Macro Scale
Nano Bins
Micro Bins
Single Hopper Midi Scale
Micro Scale
Grinder Mixer
24 | July 2020 - International Aquafeed
Nano Scale