Roller Press Throughput Measurement: Gap, Density and Slip Correction
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Solution Overview
Problem
Existing methods for measuring the throughput of a roller press in cement production are inaccurate due to changes in bulk density, sliding between the roll and material cake, uneven wear of the roll surfaces, and time-varying operating conditions, leading to errors in calculation results.
Innovation Solution
A real-time detection system and method using a central control system, fixed and movable roll profile measurement systems, encoders, and a DCS system to measure roll gaps and surface profiles, incorporating bulk density, sliding, and roll retraction corrections to calculate accurate throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the direct measurement method uses the bulk density of the material cake after extrusion, then the measurement process is simple, but the measurement precision deteriorates because the material cake expands over time causing bulk density to decrease
Solution Approach 1:
The patent applies preliminary action by measuring the bulk density of the material cake immediately after extrusion, before the material has time to expand and change density. This timing ensures the density measurement reflects the actual extrusion conditions, preventing the accuracy degradation that would occur if measurement were delayed.
2Device complexity
If the direct measurement method assumes no slip between roll and material cake, then the calculation is simplified, but the measurement precision deteriorates due to actual sliding occurring
Solution Approach 1:
The patent introduces feedback by measuring the actual linear speed of the material cake using sensors and comparing it with the theoretical roll speed. This feedback mechanism allows the system to detect and compensate for sliding between the roll and material cake, correcting the throughput calculation to reflect actual operating conditions.
3Device complexity
If the direct measurement method uses the average roll gap from two displacement sensors, then the measurement is simplified, but the measurement precision deteriorates due to uneven roll surface wear creating saddle-shaped surfaces
Solution Approach 1:
The patent applies segmentation by dividing the roll gap measurement into multiple discrete points across the roll width using multiple displacement sensors. Instead of relying on a single average value, the system measures roll gap at several locations and processes these individual measurements to account for uneven wear patterns and saddle-shaped roll surfaces, thereby improving measurement accuracy.
4Device complexity
If the indirect measurement method uses elevator current to calculate throughput, then direct measurement of roll parameters is avoided, but the measurement precision deteriorates due to motor efficiency variations and changing no-load current
Solution Approach 1:
The patent introduces feedback mechanisms to continuously monitor and adjust for changes in motor efficiency and no-load current. By measuring actual operating parameters and comparing them with reference values, the system can compensate for drift and variations, maintaining accurate throughput measurements despite changes in elevator operating conditions over time.
Data Source
Figure 1~3
AI summary
The present invention discloses a real-time detection system for detecting throughput of a roller press and a detection method. The detection system comprises a central control system, and a fixed roll profile measurement system, a movable roll profile measurement system, a fixed roll encoder, a movable roll encoder, and a DCS system, which are electrically connected to the central control system, respectively. In the detection method, the direct measurement method shown in formula (1) is improved, the displacement of the movable roll is considered, and a bulk density correction coefficient, a sliding correction coefficient, and a roll retraction correction coefficient are introduced to correct the calculated throughput. Compared with the direct measurement method in the prior art, the present invention can accurately obtain the real-time throughput of the roller press.