|
RAC System - Rotary Air Curtain.
| The RAC system has been developed to provide dust control and to dilute
released methane gas during longwall coal mining operations. Its
success is unprecedented in being the primary mode for ignition
control over many years throughout the UK coal industry. Longwall
ignitions have subsequently been eliminated.
The RAC system in conjunction with Hydra's ITPP
cutting system reduces dust levels and the risk of frictional ignition to the
absolute minimum. |
|
The RAC system is water based, and uses high pressure water, at a nominal
pressure of 100bar to form air movers. A series of air movers are
displaced equally around the inside barrel of the shearer drum and
force air away from the coal face towards the shearer machine, which
has the following beneficial effects:-
| 1. As coal is cut, methane gas is naturally released; the RAC system draws
the methane gas through the air moving tubes and dilutes the gas to
below an explosive level. |
 |
|
| 2. As the water saturated air is forced out of the air moving tubes, it is
directed across the cutter picks/bits of the shearer drum, this
induces fresh air into the cut, it also forms an air curtain around
the shearer drum containing any dust that is made, within the
cutting zone. |
 |
|
| 3.
The water saturated air, moving across the cutter picks/bits is
attracted to any airborne respirable dust and captures the dust
turning into slurry.
|
| 4.
The slurry falls to the floor with the cut product, and
|
| 5.
The process continues.
|
| | The design
of the shearer drum will accommodate the appropriate number of air
moving tubes, dependent on the predicted methane gas release.
|
|