Quasi-static pressure compensation for asphalt weighing
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Solution Overview
Problem
In discontinuously operating asphalt mixing plants, the introduction of undried recycling material causes pressure fluctuations due to water evaporation, disrupting the weighing process and leading to economic losses, quality deviations, and inefficient dust management.
Innovation Solution
Implementing quasi-static pressure compensation and correction by using pressure measuring points to dynamically record pressure curves and adjust the weighing process, allowing continuous and precise addition of additives without interrupting the mixing process, even with undried recycling material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If undried recycled material is added to the mix, then processing efficiency is improved and separate drying equipment is avoided, but pressure fluctuations occur due to water evaporation which disrupts the weighing process
Solution Approach 1:
The patent implements a feedback mechanism where pressure sensors continuously monitor pressure fluctuations in the mixing chamber and transmit this information to the control unit. The control unit then adjusts the weighing process in real-time based on the pressure feedback, allowing continuous operation without interruptions while maintaining weighing accuracy despite water evaporation from undried recycled material.
Solution Approach 2:
The patent changes the operational parameters of the weighing system by introducing dynamic correction values that adjust weighing measurements based on real-time pressure conditions. This allows the system to accommodate pressure variations from water evaporation without compromising weighing precision, enabling continuous processing of undried recycled material.
2Measurement precision
If the weighing process is interrupted to allow pressure to return to normal, then weighing accuracy is maintained, but economic losses occur due to reduced throughput during peak periods
Solution Approach 1:
The control unit receives continuous pressure feedback from sensors and dynamically adjusts weighing operations without interruption. By monitoring pressure levels in real-time, the system can compensate for evaporation-induced fluctuations and maintain accurate measurements throughout the mixing process, eliminating the need for time-consuming interruptions.
Solution Approach 2:
The patent enables continuous weighing operation by implementing pressure compensation algorithms that adjust measurements in real-time. This eliminates the need to interrupt the weighing process to wait for pressure normalization, maintaining both accuracy and continuous material flow for improved throughput during peak periods.
3Stress or pressure
If the extraction capacity of the dust extraction system is increased to quickly reduce overpressure, then pressure control is improved, but flow velocities increase causing dusty aggregates to be discharged and quality requirements are not met
Solution Approach 1:
Pressure sensors provide continuous feedback on pressure levels in the mixing chamber, allowing the control unit to make precise, incremental adjustments to the dust extraction system. This feedback-controlled approach maintains pressure within acceptable ranges without creating excessive flow velocities that would discharge dusty aggregates, thereby preserving aggregate quality while effectively controlling pressure.
Solution Approach 2:
The dust extraction system operates dynamically with adjustable capacity rather than at fixed high capacity. The control unit modulates extraction strength based on real-time pressure conditions, providing sufficient pressure control to manage water evaporation while avoiding excessive flow velocities that would compromise aggregate quality through premature discharge.
4Measurement precision
If multiple pressure measuring points are distributed across the entire circumference, then representative pressure measurement is achieved, but device complexity increases
Solution Approach 1:
The pressure measurement system is segmented into multiple distributed sensing points around the mixing chamber circumference. Each sensor captures local pressure conditions, and the control unit aggregates these segmented measurements to determine the overall pressure state. This segmentation approach provides comprehensive pressure monitoring while using simple, standardized sensor components.
Solution Approach 2:
Multiple pressure sensors perform the same universal function of measuring local pressure conditions. By distributing identical multi-functional sensors throughout the system, the patent achieves representative pressure measurement without requiring complex specialized measurement devices, thereby balancing measurement precision with system simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous and precise weighing of additives, maintaining quality standards, reducing economic losses, and ensuring consistent dust management by accounting for pressure fluctuations, allowing undried recycling material to be used without affecting the asphalt mix quality.
Implementation Method 1
The area above and below the weighing unit is equipped with multiple pressure measuring points to dynamically record the pressure profile during a mixing process
Implementation Method 2
The water they contain evaporates rapidly, resulting in a sudden pressure increase in the agitator and below the weighing unit
Data Source
AI summary
The invention relates to quasi-static pressure compensation and correction of the weighing process in batch asphalt mixing plants, in particular pressure measurement and an associated corrected weighing method. In accordance with legal requirements, recycled material is added to the mix. Depending on the weather conditions, the recycled material contains water, which evaporates rapidly along with the other, still hot, aggregates in the agitator. This evaporation impairs the weighing process, necessitating either a temporary interruption of the weighing process or the drying of the recycled material. For quasi-static pressure compensation and correction of the weighing process, pressure measuring points are arranged below and above the mineral weighing unit to dynamically record the pressure profile during the mixing and weighing process.The measured pressures are used to correct the weighing procedure, with a correction value for the weighing unit being determined at each point in time. The weighing procedure is then carried out using the corrected weighing parameters. This allows recycled material to be added to the asphalt mix, either partially dried or undried, without negatively affecting the quality of the asphalt mix.