Longwall Shield Height Control via Inclination Sensors
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Solution Overview
Problem
In longwall mining, existing automated control systems lack precision in creating a sufficient face opening to prevent collisions between extraction machines and shield support frames while minimizing rock collapse and excessive country rock cutting, due to imprecise mineral deposit data.
Innovation Solution
A method using inclination sensors on shield support frames and extraction machines to accurately determine the cutting height and shield height, allowing for location-synchronous analysis and automatic control of the extraction machine to maintain a defined face opening, incorporating data on seam thickness and strata conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automated control is used based on imprecise mineral deposit data, then automation extent is improved, but measurement precision of face opening dimensions deteriorates
Solution Approach 1:
The patent replaces traditional mechanical measurement methods with sensor-based detection systems. Sensors mounted on the extraction machine and shield support frame detect cutting height and shield height electronically, providing precise real-time data that substitutes for imprecise mineral deposit data and manual measurement methods.
Solution Approach 2:
The patent implements a feedback control system where sensor data on cutting height and shield height is continuously monitored and fed back to the control system. This feedback loop enables automatic adjustment of extraction machine parameters to maintain optimal face opening dimensions, resolving the contradiction between automation and measurement precision.
2Productivity
If extraction machine travels past shield support frames, then productivity is improved, but reliability of collision-free operation deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting shield height in advance before the extraction machine reaches the critical passage zone. The sensor system measures shield height at multiple positions ahead of time, allowing the control system to pre-calculate safe passage parameters and adjust extraction machine height before collision risk occurs.
Solution Approach 2:
The patent implements dynamic adjustment of extraction machine cutting height based on real-time shield height measurements. The system continuously adapts the extraction machine's vertical position to match the actual shield support frame height, ensuring collision-free passage while maintaining high productivity through automated control.
3Reliability
If cutting height is increased to ensure sufficient face opening, then reliability of equipment passage is improved, but loss of substance through excessive country rock cutting increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the extraction machine's cutting height parameter based on real-time shield height measurements. Instead of using fixed or excessive cutting heights, the system optimizes the cutting parameter to match the actual shield position, ensuring sufficient face opening for equipment passage while minimizing unnecessary country rock removal.
Solution Approach 2:
The patent implements local quality by tailoring the cutting height to the specific local conditions at each measurement point. The sensor system detects variations in shield height across different locations, and the control system adjusts cutting parameters locally to match the actual geological conditions, preventing excessive cutting in areas where the shield provides adequate support.
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
This method provides precise and reliable control of the longwall operation, ensuring a stable face opening by adjusting the cutting height based on real-time data, reducing collisions and rock collapse, and adapting to changes in strata conditions.
Implementation Method 1
the inclination of the shield components in relation to the horizontal in the advancing direction is ascertained using inclination sensors attached to at least three of the four main components of each shield support frame
Implementation Method 2
the cutting height of the extraction machine is detected as the face opening using sensors attached to the extraction machine
Data Source
AI summary
A method for automatically producing a defined face opening in a longwall mining operation, in underground coal mining, having a face conveyor, at least one extraction machine and hydraulic shield support frames. Inclination sensors are disposed on at least three of the four main components of each shield support frame, such as floor skid, gob shield, support connection rods and gob-side area of the top canopy. From ascertained inclination data, by comparison with base data defining a geometrical orientation of the components and a movement thereof during stepping, a respective shield height of the shield support frames perpendicular to a bed thereof is calculated. From further sensors on the extraction machine, a cutting height thereof is acquired as a face opening. In terms of a location-synchronous analysis, for possible adjustment purposes the cutting height is compared with the shield height when the shield support frame, which trails the extraction machine with a time delay, has reached the position to which relates that cutting height which was used in the comparison.