A gravimetric dosing device according to the “differential scale“ method measures the mass flow in the following way:

  • The system weight is captured each time after a measurement time Δt
  • The weight loss ΔG after the measurement time Δt determines the flow rate per unit time (mass flow =ΔG / Δt)

Consequences:

  • The current measured value of the mass flow is only available at discrete instants of time
  • The dosing controller must always wait a measurement time Δt, before it can initiate a correction of the discharge (“the controller always chases afterward“)

Remedy:

  • Apply an integrating Loss in Weight Feeder (“integrating scale“ method)

see integrating Loss in Weight Feeders