Many quartz sand production lines have reported problems such as motor
overload tripping or fluctuating operating current. On the surface, it appears
to be a motor malfunction, but the root cause is mostly due to the fit between
the impeller and the groove.
Excessive or insufficient clearance between the impeller and the bottom of
the tank can cause abnormal current. Quartz sand has high hardness, and after
long-term operation of the impeller, the gap between its lower end face and the
bottom of the tank will gradually increase. When the gap is too large, the
impeller cannot effectively drive the sand material deposited at the bottom to
participate in scrubbing, and some coarse particles accumulate at the bottom of
the groove, increasing the motor load and causing periodic fluctuations in the
ammeter reading. It is recommended to stop the machine and measure the gap once
a month, usually within the range of 5-8mm. If it exceeds this range, the
impeller position needs to be adjusted or worn parts need to be replaced.
Loose or broken impeller bolts can also cause current fluctuations. The
impeller continues to withstand the impact of quartz sand particles during
high-speed rotation. If the fixing bolts are not tightened according to the
specified torque, they are prone to loosening or even breaking. The loose
impeller swings and runs inside the groove, causing the current reading to
fluctuate. During each shutdown maintenance, use a torque wrench to check the
fixing bolts of the impeller one by one. If any looseness is found, tighten them
immediately. If the bolt head is severely worn, replace it in a timely
manner.
Choosing the wrong impeller material and wearing it out too quickly can also
cause load fluctuations. Ordinary carbon steel impellers often have a lifespan
of less than three months under quartz sand scrubbing conditions. Polyurethane
coated impellers have good wear resistance and their service life is usually 2-3
times that of rubber impellers. It is also necessary to control the scrubbing
concentration between 60% -70%. If the concentration is too high, the slurry
resistance will be high and the motor load will increase. If the concentration
is too low, the scrubbing effect will be compromised.
In addition, the uneven surface of the wear-resistant plate on the inner
lining of the tank can also interfere with the flow state of the slurry near the
impeller, exacerbating current fluctuations. When abnormal current is found, it
is recommended to investigate in the order of "measuring the gap first, then
checking the bolts, and finally checking the lining".
For specific parameters on the operation and maintenance of the scrubbing
machine, please contact the technical team of Shandong Heavy Industry at Manager
Zhang 13583776655 (same as WeChat).