STORAGE
F
Grain conveyors: examining this important piece of equipment by Mike Spillum, Hi Roller, US
I
Hi Roller Conveyors, Sioux Falls, South Dakota, specialises in the design and manufacturing of enclosed belt conveyors for grain and grain byproducts.
t is well known that grain dust is very dangerous. Not only is it a health hazard for workers, it is also a serious explosion hazard. Even with this knowledge, tragedies occur yearly resulting in down time, property damage, injuries, and even deaths. Although there are many methods of conveying grain, open belt conveyors had historically been the primary choice for moving large volumes or for conveying long distances. Alternative enclosed methods such as chain conveyors or screw conveyors have limitations in regards to length and capacities due to power consumption and other design constraints. Outweighing the advantages of open belt conveyors are the many negatives. They can be messy. Although the majority of outdoor installations include covers, they are still exposed to wind and the elements resulting in dust clouds and spillage. Indoor installations create a health and safety hazard if dust is not contained. The cost of proper dust collection equipment and associated maintenance can be high. Product spillage results in lost profits and requires additional employees to perform clean up. While cleaning around open belt conveyors, employees are
42 | Milling and Grain
exposed to the hazardous dust and can become injured working around moving parts. As a contractor serving the grain industry in the 1970’s, Hi Roller’s founder felt that there had to be a cleaner, safer, more efficient way to convey grain. Numerous attempts had been made to enclose conventional open belt conveyors. Companies were utilising standard conveyor components and cumbersome reloading designs to address product spillage issues. Enclosures were being built around standard conveyor idlers. Product would build up on idler brackets and other ledges. While containing dust within the enclosure, they were exposing the explosive grain dust to the idler bearings. A failed bearing can create heat or a spark resulting in a fire or an explosion. The return side of the conveyor belt slid on a steel pan rather than rollers. Grain that fell to the bottom of the enclosure was conveyed to the tail end of the conveyor. The reloading of product at the tail section was attempted by utilising “loop conveyors” which incorporated chains, paddles and multiple gearboxes. If any of these items failed, product could build up which again created a maintenance or explosion hazard. The original Hi Roller design was developed nearly 40 years ago and continues to be the standard of the industry for the clean, safe conveying of bulk materials. The Hi Roller was designed with some primary goals in mind. First, it needed to be totally enclosed. Second, there were to be no internal brackets or ledges that would allow product to build up. Third, it needed to be self-cleaning and self-reloading. Fourth and most importantly, there could be no bearings exposed to the internal atmosphere of the conveyor. In order to accomplish all of the above, innovate conveyor components needed to be used.