Rock Dust Mine Wall Application Combining Foam and Slurry
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Solution Overview
Problem
Existing methods for applying rock dust in coal mining face challenges such as foam deterioration and pumping issues when using foamed compositions, particularly when air is used to entrain rock dust, leading to ineffective adhesion and uniformity of the rock dust on mine walls.
Innovation Solution
Combining a foam with a rock dust and water slurry downstream of the pump, eliminating the need for air entrainment, and using a combiner to mix the foam, water, and rock dust near the application point, ensuring a uniform and stable foam-rock dust mixture is applied to the mine wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air is used to entrain rock dust in the conduit, then rock dust can be transported to the application point, but the foam deteriorates due to air contact
Solution Approach 1:
The system separates the rock dust transport function from the foam delivery function by using two independent conduits. Rock dust is transported through a first conduit without air entrainment, while foam is delivered through a second conduit. The mixing occurs only at the application point, preventing foam deterioration from air contact during transport.
Solution Approach 2:
Water serves as an intermediary medium to transport rock dust without requiring air entrainment. The rock dust is suspended in water through the first conduit, eliminating the need for air-based entrainment that would cause foam deterioration. The water-entrained rock dust then mixes with foam at the application point.
2Ease of manufacture
If foam is mixed with rock dust upstream of the pump, then mixing occurs before delivery, but the foam deteriorates during pumping and transport
Solution Approach 1:
The system prepares rock dust suspension in advance by mixing rock dust with water in a tank before pumping. This preliminary mixing occurs without air contact, preserving foam stability. The actual foam-rock dust mixing is delayed until the application point, preventing foam deterioration during pump transport.
3Productivity
If a foamed composition is pumped through long conduits, then delivery is achieved, but foam deterioration increases and uniformity is reduced
Solution Approach 1:
The system divides the delivery system into separate conduits for rock dust and foam, eliminating the need to pump a foamed composition through long conduits. Each component is delivered separately and mixed at the application point, maintaining foam stability and application uniformity even over long distances.
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 approach reduces foam deterioration and ensures a uniform application of rock dust, enhancing its effectiveness in suppressing mine fires and explosions by maintaining the quality of the foam-rock dust mixture, even over longer conduit lengths.
Implementation Method 1
a foam generator for mixing a foamable liquid and air to produce a flowable foam
Implementation Method 2
a pump, having an inlet in communication with the vessel receives the mixture and delivers the mixture through a first conduit
Implementation Method 3
The combiner has an internal chamber arranged to receive the mixture of rock dust and water from the first conduit and the flowable foam from the second conduit
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 a suspension of rock dust in water through another flexible conduit to a combiner, and causing the combined foam, rock dust and water to pass through a flexible hose to a delivery nozzle from which it is applied to a mine wall.