The hydraulic classifier has been running for about a year, and the outer
edge of the spiral blades has noticeably become thinner, with a larger gap
between them and the inner wall of the tank, resulting in a decrease in
classification accuracy. Blade wear is a problem that cannot be bypassed by such
equipment, but the speed of wear varies depending on how well the blade
material, speed, and material level in the slot are controlled.
Choosing the wrong blade material can accelerate the wear rate exponentially.
Under the abrasion of quartz sand, a large section of the outer edge of ordinary
carbon steel blades is worn off in three to five months. It is recommended to
use wear-resistant steel (such as NM400) or weld a wear-resistant layer on the
outer edge of the blade, which can extend the service life by two to three
times. Pay attention to controlling the interlayer temperature during welding to
avoid blade deformation. Some manufacturers provide polyurethane coated blades,
which have better wear resistance and lighter weight, and also have less load on
the spiral shaft.
The spiral speed is too high, and the friction between the blades and the
sand material intensifies. When the rotational speed exceeds the design value,
the blade linear velocity increases, and the impact and friction strength with
quartz sand particles increase, naturally accelerating wear. Check if the output
frequency of the frequency converter exceeds the rated value, and adjust the
speed appropriately if it exceeds the standard. After the speed decreases, it is
necessary to observe the grading effect synchronously. If the overflow runs
rough, the compensation for the rising water flow should be appropriately
increased.
The material level in the groove is too low, and the idle dry grinding of the
blades also accelerates wear. When the material level is lower than the
centerline of the spiral shaft, some blades are exposed to the liquid surface
and idle, unable to obtain lubrication and cooling from the slurry. The wear
rate is much faster than being immersed in the slurry. Keep the material level
in the tank stable above the centerline of the spiral shaft by adjusting the
height of the overflow weir and the feeding amount. Observe the level gauge
reading once per shift, and check if the feeding and discharging match when
there is a large fluctuation.
During daily inspections, measure the gap between the outer edge of the blade
and the inner wall of the groove once a month. If it exceeds the design value by
1.5 times, arrange for welding repair or replacement of the blade. Encountering
problems during equipment operation, welcome to contact the technical team of
Shandong Heavy Industry for communication: Manager Zhang 13583776655 (same as
WeChat).