Rock Dust Foam Application Apparatus for Mine Walls
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Solution Overview
Problem
Existing methods for applying rock dust in coal mining, such as mixing foam and rock dust in a vessel and then transporting it to the mine wall, are time-consuming and inefficient, and may not ensure adequate adhesion or distribution, particularly over long distances.
Innovation Solution
Combining rock dust and foam at the point of application on the mine wall using an apparatus with separate conduits for air-entrained rock dust and flowable foam, which are then mixed and applied through a nozzle, allowing for real-time adjustment of the rock dust and foam composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rock dust and foam are mixed in a vessel and transported to the mine wall, then the mixture can be applied, but the process becomes time-consuming and inefficient
Solution Approach 1:
The system divides the rock dust and foam into separate conduits (first conduit for rock dust/air mixture, second conduit for foam), allowing them to be transported independently and combined only at the point of application. This segmentation eliminates the time-consuming mixing and transport of pre-mixed material while maintaining effective application.
Solution Approach 2:
The rock dust is pre-entrained in air in the first conduit before reaching the mixing point, and foam is prepared separately in the second conduit. These preliminary preparations allow for rapid combination at the application point without requiring extensive mixing time, thus improving productivity while minimizing time loss.
2Reliability
If rock dust is applied without foam, then the application process is simpler, but adhesion to mine surfaces is insufficient
Solution Approach 1:
Foam acts as an intermediary substance that facilitates adhesion between rock dust and mine surfaces. The foam carrier provides the necessary bonding properties that plain rock dust lacks, ensuring reliable adhesion. The dual-conduit system delivers both components separately, combining them only where needed, thus managing complexity while achieving reliable results.
Solution Approach 2:
The system creates a composite application mixture of rock dust and foam at the point of use. This composite material combines the fire-suppressing properties of rock dust with the adhesive properties of foam, achieving reliable adhesion. The separate conduit system delivers each component independently, managing apparatus complexity while enabling the composite effect.
3Manufacturing precision
If rock dust and foam are mixed in advance, then the mixture is ready for application, but adequate distribution particularly over long distances cannot be ensured
Solution Approach 1:
By segmenting the transport system into separate conduits for rock dust/air mixture and foam, the system maintains component separation during long-distance transport. This prevents settling and distribution problems that would occur with pre-mixed material, ensuring uniform distribution even over long distances from the mixing point to the application point.
Solution Approach 2:
The system uses pneumatic transport (air-entrained rock dust in first conduit) to carry rock dust particles uniformly over long distances without settling. The foam in the second conduit is delivered separately and combines at the application point, ensuring both components maintain their distribution characteristics throughout long-distance transport.
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 enhances the adhesion and distribution of rock dust, reduces fugitive dust, and allows for efficient and rapid application of high volumes of the rock dust-foam mixture, minimizing equipment movement and enabling adjustments to be made on-site to meet specific conditions, thereby improving fire suppression and explosion prevention.
Implementation Method 1
means are provided for entraining rock dust in air in the first conduit
Implementation Method 2
means are provided for mixing a foamable liquid and air to produce a flowable foam
Implementation Method 3
A nozzle connected to the combining means is provided for applying a mixture of air, rock dust and foam from the combining means to a mine wall
Data Source
AI summary
Rock dust is applied to a mine wall for mine fire suppression in combination with a chemical foam, by generating the foam from air and a foamable liquid in a mixing chamber, and delivering the foam through one flexible conduit and air-entrained rock dust through another flexible conduit to a portable assembly composed of a Y-joint and a delivery nozzle for combining the foam and rock dust and applying the combination directly to a mine wall.