The significant demands placed on weighing and control operations in loss-in-weight feeding

In practice, with today’s advanced weighing and control technologies, reliably high performance accuracy is routinely realized, notwithstanding the significant demands placed on weighing and control operations in loss-in-weight feeding.

Loss-in-weight feeding systems are available for the complete range of rates encountered in plastics compounding and extrusion operations.Any feeding device suitable to the process material can be employed (e.g., screw, auger, vibrating tray, etc.).

 

Under the loss-in-weight feeder principle, moment-to-moment differences in weight matter, not absolute weight.Thus, for the purpose of feed rate control, tare becomes irrelevant.Considering the fact that loss-in-weight feeding involves the accurate detection of small, moment-to-moment changes in system weight while simultaneously weighing a relatively massive feeding system, the demands on the weighing system are substantial.

Such measurement requires the highest possible levels of resolution, linearity and stability along with sophisticated filtering and signal processing to extract meaningful weight data from spurious disturbances such as jostling or ambient vibration in the process environment.