Mass Flow Determination with Friction Compensation
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Solution Overview
Problem
Existing methods for determining mass flow of bulk materials, such as grain, using continuous conveyor systems are limited in precision due to uncompensated frictional forces, tilting, external mechanical forces, and varying bulk material properties like moisture content, which affect force measurements on sensor surfaces.
Innovation Solution
A method and control device that compensates for frictional forces, tilting, external mechanical forces, and bulk material properties by using a load cell designed as a platform weighing cell, sensors for monitoring tilting and rotational rate, and adjusting detection characteristics based on moisture content and material type, ensuring accurate mass flow determination independent of density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force measurement is used to determine mass flow, then throughput determination is achieved, but measurement precision deteriorates due to uncompensated frictional forces and external effects
Solution Approach 1:
The harmful frictional forces and external effects are extracted and separated from the measurement process. A compensation device is introduced that specifically measures and compensates for these interfering forces, allowing the sensor surface to maintain contact with bulk material while eliminating their negative impact on measurement precision.
Solution Approach 2:
The system changes the measurement parameters by introducing compensation values for frictional forces and external effects. The control device adjusts the mass flow determination by applying these compensation parameters, transforming the measurement from being affected by external factors to being corrected for them, thereby improving precision.
2Reliability
If sensor surface contacts bulk material for force measurement, then mass flow determination is possible, but measurement reliability deteriorates due to varying bulk material properties
Solution Approach 1:
The system implements feedback by continuously monitoring bulk material properties and using this information to adjust the measurement. The control device receives signals about bulk material characteristics and automatically compensates for their effect on the force measurement, maintaining reliable results despite property variations.
Solution Approach 2:
The measurement system is made universal by enabling it to handle different bulk material properties. Through the compensation device and control algorithm, the same sensor surface and force measurement principle can reliably measure mass flow for various types of bulk materials with different properties, making the system adaptable and versatile.
3Productivity
If continuous conveyor is used to transport bulk material, then productivity is improved, but device complexity increases due to additional compensation mechanisms
Solution Approach 1:
The compensation device is merged with the existing conveyor system. The force sensor, compensation device, and control unit are integrated into the continuous conveyor structure, allowing mass flow determination and friction compensation to occur within the same system without requiring separate transport mechanisms, thus limiting the increase in complexity.
Solution Approach 2:
Complex mechanical compensation mechanisms are replaced with a control-based approach. Instead of using additional mechanical components to physically compensate for friction, the system uses sensors to detect frictional forces and applies computational compensation through the control device, substituting mechanical complexity with electronic/control 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
Improves the precision of throughput determination by accurately accounting for various parameters affecting force measurements, providing reliable and consistent mass flow calculations across different conditions.
Implementation Method 1
The mass flow is determined by the measurement of a resulting centrifugal force exerted on a sensor surface of the measuring device
Implementation Method 2
A first parameter, which is compensated for in the determination of the mass flow with respect to the throughput conveyed by the conveyor, are the frictional forces imposed on the sensor surface by the bulk material as it flows past
Data Source
AI summary
A method for determining a mass flow composed of bulk material, in particular grain, which is conveyed by means of a continuous, circulating conveyor, having planar conveyor elements, from a lower bulk material receiving area to a higher bulk material delivery area, in which the bulk material delivered by the conveyor is deflected by a guide surface disposed in the bulk material delivery area toward a measuring device, wherein the mass flow is determined by the measurement of a resulting force (F_G) exerted on a sensor surface of the measuring device, wherein at least two parameters having an effect on the force measurement, in particular parameters independent of bulk material properties, are compensated for. A control and regulating device for executing the method for determining a mass flow composed of bulk material is also provided.