Level measurement in a lime kiln |
The application
The production of burned lime is carried out via rotary tube furnaces or kilns that operate continuously with batch charges. Level control in the kiln in batch operation is especially important because the end quality of the lime depends heavily on the speed with which it is removed from the kiln. This measurement is normally carried out with a mechanical plumb line system. Because the sensing weight is exposed to extreme forces, however, plumb line systems require frequent servicing. Radiometric measuring systems are also used as an alternative. But these systems require a very involved setup and initial operation, extensive safety procedures as well as periodic checks by a radiation protection officer.
The process data
| Medium: | lime, dielectric value: 1.4 |
| Vessel: | lime kiln |
| Regulated height: | 2 m |
| Vessel material: | steel and refractory lining |
| Temperature of medium: | approx. 700 °C |
| Temperature of flue gases: | +200 … +300 °C |
| Pressure: | atmospheric pressure |
The solution
The ideal solution is the radar sensor for bulk solids, VEGAPULS 68, in high temperature version. The sensor monitors the emptying of the kiln permanently and contactlessly. An optional rinsing air connection provides cooling and keeps the antenna system free of dust.
The advantages
 | Simple setup and commissioning |
| Measurement exactly reproducible even with very small dielectric constant |
| Continuous measurement |
| Maintenance-free system, non-contact and wear free |
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