A novel spraying/negative-pressure secondary dust suppression device used in fully mechanized mining face: A case study

Aiming at improving the spraying dust suppression performances between the coal cutter hydraulic supports, a novel spraying/negative-pressure secondary dust suppression device was developed. In this device, the nozzle's atomization performance including atomizing angle, spraying range and droplet diameter were measured so as to select the optimal nozzle. A nozzle with optimal overall atomization performance was selected among 4 kinds of nozzles with hollow and solid cone-shaped spraying fields. At the optimal spraying pressure of 8 MPa, the spraying field of the developed dust suppression device can almost cover all the space between coal walls and hydraulic support's columns, and effectively absorb the dusty airflow in the footway. Field measurements indicated that, compared with the original dedusting method, the dust suppression rates of total coal dust and respirable dust in the fully mechanized mining face by the developed novel spraying device can be enhanced by 26.2% and 27.3% respectively and reach efficiencies up to 82.0% and 80.9%, respectively. The dust suppression rates of total coal dust and respirable dust in the working area for supports moving workers can be enhanced to 81.5% and 80.1%, respectively.