Bitumen temperature and the bitumen scale

Bitumen weighs correctly only when it flows correctly, and it flows correctly only at the right temperature. iAsphalt monitors the temperature in the tanks, the supply line and the scale, and does not allow dosing outside the limits.

What the system measures

• Bitumen temperature in each tank (PT100 sensors).
• Temperature of the thermal oil from the heater that warms tanks, double-walled piping and the scale.
• Temperature at the bitumen scale, before injection into the mixer.

All values are shown on the iAsphalt screen, with limits set by the operator per recipe or globally.

How the bitumen scale works

The iOLABS bitumen scale is a double-walled vessel with continuous hot-oil flow, mounted on high-accuracy load cells. On plants without a thermal-oil heater it can have its own heater with electric elements. Bitumen is weighed in the vessel and discharged to the mixer spray bar by gravity or by a bitumen pump.

What iAsphalt does during weighing

1. Checks that bitumen and oil temperatures are within limits. If not, it waits and alerts.
2. Opens the supply, monitors the flow and closes with free-fall correction so the final weight matches the recipe.
3. Sprays into the mixer at the moment the recipe defines, relative to the hot aggregates and filler.
4. Records weight, temperature and time on the batch printout.

Common issues

• Slow flow or residue in the vessel. Low oil or bitumen temperature; check the heater and the tank burner.
• Weight deviation. Check whether anything touches the scale (pipes, insulation) and calibrate in 2 steps.
• Temperature reading frozen or implausible. Probable sensor or cable fault; thermocouples are replaced without any software change.