Underground » Ventilation, Gas Drainage and Monitoring
This report describes the development and form of a shut off valve designed for gas drainage systems in underground coal mines. The valve is designed to close off flow from boreholes in the event of damage to the gas drainage pipeline.
The shut off valve developed is designed to trigger on pressure changes within the gas drainage pipeline. The principal mode of operation is through a step function pressure change associated with pipeline breakage. The pressure change may be either positive or negative depending on the pressure within the pipeline prior to breakage.
Gradual pipeline pressure fluctuations will not trigger the valve to close however pressure rises beyond a threshold will do so. Thus pipeline crushing or inadvertent valve closure will lead to borehole shut off.
The valve actuation mechanism may be used to control larger valves in the main pipeline. It also has potential use in gas supply situations.