Weighing, Dosing & Loss-in-Weight Feeding worked example

Hopper Refill Interval at 7.2% refill safety allowance: a worked example

This worked example runs the hopper refill interval numbers for a tougher week than the baseline: 7.2% refill safety allowance instead of the typical 10%. Hopper Refill Interval estimates how long a feeder hopper can run before it needs topping up, based on the usable charge and the feeder's throughput, with a safety allowance to keep the hopper above its low-level trigger.

The inputs for this scenario

  • Usable hopper charge: 120 kg (held at the documented default)
  • Feeder throughput: 12 kg / hr (held at the documented default)
  • Refill safety allowance: 7.2 % (the input this scenario stresses; the baseline uses 10)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base hopper refill interval time = required work รท processing rate.
  • Adjusted run time works out to 10.72 hr at these inputs, and this is the headline figure for the scenario.
  • Base run time works out to 10 hr at these inputs.
  • Allowance applied works out to 7.2 % at these inputs.
  • Process rate works out to 12 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where refill safety allowance sits at 10% and the headline result is 11 hr, this scenario comes in 2.55% below the baseline at 10.72 hr.
  • Use it when planning refill logistics or staffing a line so refills land on schedule rather than at random low-level alarms. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Adjusted run time: 10.72 hr (headline result)
  • Base run time: 10 hr
  • Allowance applied: 7.2 %
  • Process rate: 12 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Hopper Refill Interval calculator, set refill safety allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.