The hydraulic classifier is commonly used in quartz sand wet production lines
to process slurry from front-end grinding or scrubbing, and sudden increase in
feed rate is a common operating condition. When the front-end equipment is
adjusted or the buffering capacity is insufficient, a large amount of slurry
flows into the classifier, causing overflow and coarsening, and the bottom flow
becomes finer, resulting in an instant collapse of the classification effect.
The root of the problem lies in the fluctuation of the feed exceeding the
adjustment capacity of the classifier.
When the feeding amount suddenly increases, the rising water flow velocity is
relatively insufficient, and coarse particles are brought into the overflow
before they can settle. The upward water flow of the classifier is set according
to the normal feeding amount. When the feeding suddenly increases, the residence
time of the slurry in the tank is shortened, and the settling of coarse
particles is insufficient. Manifested as an increase in overflow concentration
and a significant increase in coarse particles in the overflow. Emergency
response involves temporarily increasing the opening of the inlet valve,
increasing the upward flow rate, and observing changes in overflow
concentration. But the fundamental solution is to add a buffer tank before the
classifier to control the feeding fluctuation within ± 10%.
A sudden increase in feed volume can also cause the bottom flow discharge to
fall behind and the material level in the tank to rise. The spiral lifting
capacity is limited, and the discharge speed of the bottom flow cannot keep up
with the influx of a large amount of materials. The material level in the groove
rises, the burial depth of the spiral blades increases, and the motor load
increases. Check if the operating current has significantly increased. If it
exceeds the standard, reduce the front-end feeding amount appropriately and wait
for the material level to fall before resuming. If there is a frequent increase
in material level, it indicates that the processing capacity of the classifier
does not match the front-end, and it is necessary to consider increasing the
equipment specifications or adding a parallel operation.
When the feed concentration fluctuates synchronously, the grading effect is
more difficult to control. An increase in feed quantity is often accompanied by
a change in concentration. When the concentration is too high, the viscosity of
the slurry increases, the settling resistance increases, and the classification
accuracy further decreases. It is recommended to install concentration meters
and flow meters at the feed inlet of the classifier to monitor the feeding
status in real time. Dilute with water appropriately when the concentration is
too high, reduce the amount of water when the concentration is too low, and
maintain the feed concentration stable within a reasonable range.
Record the feeding amount and grading effect for each shift in daily
operations, and prioritize addressing buffering issues when frequent feeding
fluctuations are found. Encountering problems during equipment operation,
welcome to contact the technical team of Shandong Heavy Industry for
communication: Manager Zhang 13583776655 (same as WeChat).