Written by DSI Copyright 2010 nodust.com
Hoppers located near waterways face certain challenges. Regulations often require that no dust or materials from the hopper loading operation enter the water. Areas near waterways often have increased wind conditions that complicate controlling the dust. DSI utilizes it Dry Fog System in conjunction with DustTamer Wind Screen Systems as shown in the photo. The DustTamer fabric screen is installed on the perimeter of the hopper typically on three sides. The fabric serves several purposes:
- Due to the fabrics porosity, ambient wind is directed away form the hopper pocket by allowing some air bleed through that equalizes the pressure on both sides of the screen. If the screen were solid the wind will hit the solid wall and seek out the low pressure inside the hopper. This air movement pushes the dust out of the pocket.
- This same pressure equalization effect allows for the Dry Fog to stay in the pocket along with the airborne dust for a long enough period of time for the micron size droplets to attach to like size airborne dust particles. The agglomerated particles will then fall back into the hopper without wetting the material.
- The fabric will also help capture larger particles that become airborne form the the loading of the hopper.
- If the loading of the hopper is from a large and sudden dump (grab bucket or E-Crane) the screen helps contain the fog that is generated at the hopper prior to the dump. This "pre-fog" provides a large reservoir of fog droplets in a high concentration that scrubs the air when the dump occurs and air displacement can project dust particles into the air.
Green Port Magazine Article on Dry Fog Dust Suppression