Returning material from the feed inlet during the operation of the drum
screen is a problem encountered by many customers. Sand is poured out from the
feeding port and needs to be manually cleaned when it falls on the ground, which
not only wastes materials but also increases workload. When the return of
materials is severe, the outer part of the feed end cylinder accumulates into
small mountains, forcing the screening operation to be interrupted. The problem
usually lies in the matching of the feeding chute angle, cylinder speed, and
feeding amount.
The main reason for material return is the slow angle of the feeding chute.
When the angle of the chute is below 45 °, the flow of quartz sand in the chute
is not smooth. When the material falls to the feeding end of the cylinder, the
speed is insufficient, and it cannot slide smoothly into the cylinder. Some sand
rebounds and falls back, overflowing from the feeding port. Check the actual
inclination angle of the chute, if necessary, increase it to 50 ° -60 °, and
install wear-resistant lining plates on the inner wall of the chute to reduce
frictional resistance. The alignment between the outlet of the chute and the
inlet of the cylinder is also crucial. When the deviation is too large, the
material hits the end plate of the cylinder and bounces back, causing material
return.
The rotation speed of the cylinder is too low, and the material accumulates
and flows backwards at the feeding end. The drum screen relies on the rotation
of the drum to move the animal material forward. When the speed is insufficient,
the material stays at the feeding end for too long and cannot be pushed towards
the discharging end. As it accumulates, it returns from the feeding port. The
normal rotation speed is generally controlled at 12-18r/min, and the larger
value is taken when processing materials with high fine powder content. The
speed adjustment is completed through a frequency converter, with each
adjustment of 2r/min, and the next step is determined by observing the return of
materials.
If the feeding amount exceeds the processing capacity of the drum screen,
returning the material is an inevitable result. When the feed rate exceeds the
pushing speed of the material inside the cylinder, the feed end is quickly
filled, and the newly added sand has nowhere to go, only overflowing from the
feed inlet. Check if the feeder frequency is set too high and adjust the feeding
speed appropriately. If the overall production capacity of the production line
needs to be increased, priority should be given to widening the screen surface
or replacing the drum screen with a larger specification, rather than relying on
overloaded feeding to increase production.
During daily inspections, observe whether there is material accumulation at
the feed inlet for each shift. If material is found to be returned, follow the
order of "checking the chute angle first, adjusting the cylinder speed, and
finally checking the feeding amount" for troubleshooting. Encountering problems
during equipment operation, welcome to contact the technical team of Shandong
Heavy Industry for communication: Manager Zhang 13583776655 (same as
WeChat).