In-situ monitoring of grease consistency

Abstract

The present work proposes a novel in-situ measurement technology to monitor the complex evolution of consistency during grease manufacturing. Variations in raw materials, environmental conditions, and human errors often lead to inconsistencies in the final grease consistency across production batches, causing product wastage, rework, higher costs, and production delays. To guide grease manufacturers in achieving consistent final products, a technology was developed and patented to enable real-time monitoring of rheological properties using accumulated entropy generation (AEG), a parameter derived from the principles of irreversible thermodynamics. A process sensor unit (PSU) was developed to measure AEG by recording real-time current, voltage, and process temperatures in a 5000 kg grease kettle. Tests on NLGI grade 2 and grade 1.5 grease batches demonstrated a strong linear correlation between AEG values and grease consistency, enabling a predictive model for consistency control for future batches.