Challenges and Solutions in Sealing Conveyor Loading Zones
The loading zone of a conveyor belt poses significant challenges in containing dust and fugitive materials. These materials, disturbed by their own descent and by air pressure within the transfer chute, tend to scatter upon contact with the belt.
As a result, a considerable amount of material can accumulate near the conveyor's tail or along its sides. This buildup often affects the pulley and surrounding support areas.
A common approach to mitigate this issue involves installing seals behind the loading chute, typically made from rubber or plastic. However, these systems are frequently installed loosely and may not effectively prevent material from escaping. 
Alternatively, tightly sealing the system against the belt can inadvertently turn the seal into a belt cleaner. This setup can dislodge materials adhered to the belt, which were not initially removed by the discharge point cleaner. Over time, these dislodged materials may accumulate similarly to fugitive materials, potentially falling off the conveyor near the tail pulley.
Sealing the corners of the loading chute presents an even greater challenge. The high-pressure environment at the transfer point often pushes dust past conventional seals. Moreover, fluctuations in belt tension caused by impacts from the loading chute or wing-type tail pulleys can further compromise seal effectiveness.
Currently, multiple-barrier sealing boxes are the preferred solution for containing materials at loading zones. These boxes are affixed to the back wall of the loading chute and extend to the area where the belt runs flat over the tail pulley. Retrofitting existing conveyors often involves installing a tail-sealing box in the transition area, although this approach is not recommended for new conveyors due to difficulties in sealing the transition bend.
Unlike firm seals that could act as belt cleaners, these boxes are backed by a one-way sealing strip. This design prevents materials from escaping the chute without exerting enough pressure to scrape off materials adhered to the belt. Additionally, the sides are lined with a multi-layer skirt that extends continuously to the end of the conveyor's skirt board, effectively addressing concerns related to high-pressure corners.