Feeding Accuracy
Precise feeding is crucial for consistent product quality and reliable compliance with formulations.
Why is feeding accuracy important?
Feeding accuracy is the key factor here: It indicates how accurately a feeder complies with the specified material quantity or feed rate. High feeding accuracy is particularly important when processing high-quality raw materials, when handling small feeding quantities, and in processes with strict formulation specifications.
Which factors influence feeding accuracy?
Feeding accuracy depends on both the bulk material's properties and the feeder's design and operation. Key factors include bulk density, particle size, particle shape, and flowability, as well as the material's moisture content. The weighing technology, the control system, and external factors like vibrations can also affect the feeding result.
How is feeding accuracy assessed?
The NAMUR NA 40 technical recommendation can be used to evaluate the feeding accuracy of continuous gravimetric feeding systems. It was published by NAMUR (the User Association of Automation Technology in the Process Industry) and describes a method for evaluating feeding behavior under defined measurement conditions.
A distinction is made between feeding accuracy and feeding consistency: While feeding accuracy indicates the deviation of the average feeding rate from the target value, feeding consistency describes the fluctuations in the feeding rate during operation.
How can high feeding accuracy be achieved?
In volumetric feeding, variations in bulk density can lead to deviations in the actual mass measured out. Gravimetric feeding, on the other hand, measures the mass of the fed material and allows the feed rate to be adjusted accordingly. This makes it easier to compensate for variations in material properties.
Which feeding technology can achieve the required accuracy depends on bulk material, desired feed rate, and specific process conditions.