Sequential Load Cell Weighing for Accurate Bulk Mass Flow
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Solution Overview
Problem
Existing methods for determining mass flow rates of bulk materials in conveyor systems are inaccurate and prone to errors due to uneven distribution and clumping, especially in systems like vibratory conveyors and screw conveyors, and require complex conversions from volume to mass.
Innovation Solution
A method using an array of sequentially arranged load cells to measure spatially and temporally resolved mass flow rates, allowing for direct determination by comparing load cell measurements and correlating patterns over time, which can detect and compensate for material distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gravimetric carts are used to measure mass flow rate by weighing the conveying device with material, then continuous mass flow measurement is achieved, but measurement accuracy is limited
Solution Approach 1:
The invention divides the measurement system into multiple discrete load cells arranged sequentially along the conveying path. Each load cell measures the weight of material at its specific location, creating multiple independent measurement points. This segmentation allows for more accurate determination of mass flow rate by comparing weight differences between successive measurement points, thereby improving both measurement precision and reliability.
2Measurement precision
If conveyor belt scales are used to dynamically measure quantity conveyed, then mass flow rate can be determined from weight measurements over time, but measurement accuracy is insufficient for unevenly distributed materials
Solution Approach 1:
The invention employs multiple discrete load cells positioned at different locations along the conveyor rather than a single continuous scale. This segmented approach captures the uneven distribution of material more accurately by taking measurements at multiple points, improving mass flow rate determination without requiring a complex continuous measurement system.
Solution Approach 2:
The invention creates multiple copies of the measurement function through identical load cells positioned at different locations. Each load cell replicates the weight measurement capability, and by comparing these replicated measurements across successive positions, the system achieves accurate mass flow rate determination while keeping individual sensor complexity low.
3Productivity
If material is conveyed with uneven distribution and clumping, then material flow continues but mass flow rate determination becomes inaccurate
Solution Approach 1:
By placing multiple load cells at successive positions along the conveying path, the invention captures the spatial distribution of unevenly distributed material. The comparison of weight measurements between successive load cells allows the system to accurately determine mass flow rate even when material is clumped or unevenly distributed, maintaining both continuous conveyance and measurement precision.
Solution Approach 2:
The invention uses the weight measurements from successive load cells to calculate mass flow rate in real-time. This feedback mechanism continuously monitors the material flow and compensates for uneven distribution and clumping by comparing weight differences between positions, thereby maintaining accurate measurement despite variations in material distribution.
4Measurement precision
If conventional measuring methods are used for bulk materials, then measurement is possible but the methods are expensive and complex
Solution Approach 1:
The invention uses multiple simple, identical load cells to replicate the measurement function at different positions along the conveyor. This approach achieves accurate mass flow rate measurement through the replication of basic sensing elements rather than employing a single complex measurement device, thereby reducing overall system complexity and cost while maintaining high measurement precision.
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 precise, continuous, and cost-effective measurement of mass flow rates without affecting the flow, allowing for predictive control of material feed and downstream processes.
Implementation Method 1
a conveying line (1) is provided, on which free-flowing bulk material (4) is conveyable in a conveying direction (F), wherein a multiple load cell arrangement (9) consisting of several load cells (8) arranged sequentially in the conveying direction (F) is provided on the conveying line (1)
Data Source
Figure 1
Figure 2a~2b
Figure 3~6
AI summary
The invention relates to a method for determining a mass flow rate (W) of bulk material (4) in a conveying section (1), comprising the following steps: - providing a conveying section (1) with a load cell arrangement (9) consisting of several load cells (8; X1 - Xn) arranged successively in a conveying direction (F), - continuously receiving bulk material (4), - conveying the bulk material on the conveying section in the conveying direction over the several load cells, - discharging the bulk material at an endpoint (B) of the conveying section, - outputting measured values from the individual load cells (8) as a function of time, - evaluating by comparing measured values as a function of time (t) and a position of the load cells in the conveying direction (F), - determining a mass flow rate (W) from the evaluation, wherein, in particular, the structure or sequences of measured values (Mi,t) from two or more measurements at different times are compared with each other.In this way, a distance value of the structures to the respective time difference can be determined, especially through autocorrelation.