Dust Control for Crushing Machines
The placement of the dry fog nozzles is the most important aspect to producing effective results with no wetting of material. Ideally the fog should be generated at three points and contained in properly designed shrouding. This eliminates dissipation due to wind and also produces the treatment time necessary to suppress the dust.
With crushing machines the fog is generated at the loading point allowing the droplets to be “taken in” to the crusher body. If possible, a second nozzle should be mounted at the tail end of the receiving conveyor spraying in the direction of the belt travel. Ensure any falling material cannot cause nozzle damage. As the airborne dust enters the confine, dry fog agglomeration occurs and the dust is suppressed in site and returned to the conveying material.
A general rule of thumb is that the height of the conveyor cover be approximately 1 metre above the product level on the belt. And the cover length 3 times the belt speed (m/s).
The basic principles involved for location of the nozzles are as follows:
- Nozzle spray pattern must not directly impinge upon any surface
- Nozzles should be mounted in order to maximize the ability to fill the shrouding
- Where possible the fog should avoid direct contact with the material being suppressed
- Nozzles must be protected or shielded to avoid damage from falling material
- Spray pattern of nozzles should be generated so that all the fugitive dust emissions are forced to pass through the blanket of fog