High pressure roller mill is an efficient equipment for fine crushing of
quartz sand, which achieves material crushing through high-pressure extrusion
(requiring a crushing ratio of ≥ 8:1). If the crushing ratio is insufficient
(less than 5:1) and the roller surface wears out quickly (with a service life of
less than 200 hours), it will lead to an increase in subsequent sand production
load and soaring production costs. Based on practical experience, summarize the
three-step troubleshooting method to quickly restore equipment fracture
performance.
Step 1: Check the structure and material of the roller body - the core
components determine the crushing effect
The improper material and pattern design of the roller surface are the main
reasons for low crushing ratio and fast wear.
Poor wear resistance of roller surface material: The hardness of ordinary
high manganese steel roller surface is insufficient (HRC ≤ 50), making it
difficult to withstand the strong extrusion wear of quartz sand (Mohs 7 grade);
The pattern on the roller surface is too shallow (depth<5mm) or arranged
haphazardly, making the material prone to slipping and insufficient compression.
Need to replace the high chromium alloy wear-resistant roller surface (HRC ≥
62), or use plasma spray welding strengthening treatment (surface hardness
increased by 30%); Choose a "diamond staggered pattern" (depth 8-10mm, spacing
20mm) to enhance material grip and ensure no relative sliding during
compression.
Gap or parallelism deviation between rollers: If the gap between rollers
exceeds 5mm, large particle materials may leak directly, resulting in a decrease
in crushing ratio; The parallelism deviation of the roller body is greater than
0.3mm, resulting in uneven local pressure and increased wear. Use a feeler gauge
to calibrate the gap between the rollers to 2-3mm, and adjust the gap on both
sides synchronously by adjusting the screw; Use a laser leveling instrument to
detect parallelism, tighten the bearing seat bolts, and ensure that the roller
body runs without deviation.
Step 2: Calibrate pressure parameters and speed - parameter matching improves
crushing efficiency
Improper settings of squeezing pressure and roller speed directly affect the
crushing effect and wear speed.
Insufficient or fluctuating extrusion pressure: When the working pressure is
below 8MPa, the material only breaks on the surface, making it difficult to form
an effective crushing ratio; The pressure fluctuation exceeds 2MPa, resulting in
unstable crushing effect. By increasing the pressure through the hydraulic
system, the working pressure is stabilized at 10-12 MPa, and a pressure sensor
is installed to achieve closed-loop control. When the pressure drops, it is
automatically replenished; Check the quality of hydraulic oil. If the oil
contamination level exceeds NAS level 8, replace the anti-wear hydraulic oil in
a timely manner to avoid pressure disorders caused by oil circuit blockage.
The roller speed is too fast or too slow: the speed exceeds 30r/min, the
material residence time is less than 0.5 seconds, and the extrusion is
insufficient; Below 20r/min, production capacity decreases and local wear on the
roller surface is concentrated. Use a tachometer to detect and adjust to
24-26r/min, and achieve stepless speed regulation through a frequency converter;
According to the dynamic optimization of material particle size, when the feed
particle size is greater than 20mm, the rotational speed (24r/min) should be
appropriately reduced to extend the extrusion time; When the feed particle size
is less than 10mm, increase the speed (26r/min) to improve production
capacity.
Step 3: Optimize material pretreatment and maintenance - source control to
reduce wear and tear
The lack of material characteristics and maintenance can exacerbate equipment
problems.
Raw materials with impurities or high moisture content: mixing with hard
objects such as metal blocks and granite (hardness>8 levels) can impact the
roller surface and cause pits; If the moisture content exceeds 6%, the material
is prone to sticking to the roller surface and forming "lumps", which affects
the extrusion effect. Install iron removal device and grille (aperture ≤ 15mm)
before feeding to remove hard objects and large impurities; For high moisture
content materials, a pre drying process is added to reduce the moisture content
to below 4%, or a dispersing device is installed at the feed inlet to break down
the adhesive clumps.
Lack of maintenance or insufficient lubrication: The lack of oil in the
bearings causes the roller body to run slowly, resulting in localized pressure
concentration; Failure to clean the roller surface in a timely manner
exacerbates the wear of the adhesive material. Check the bearing temperature
daily (≤ 70 ℃) and add high-temperature lubricating grease (using lithium based
grease) every week; Install an automatic roller cleaning device (such as a
scraper cleaner) to scrape off the adhesive material on the roller surface in
real time; Every 100 hours, use an ultrasonic detector to detect the wear on the
roller surface. When the wear depth exceeds 3mm, repair or replace the roller
surface.
Extra attention should be paid in daily life: check the hydraulic system
seals every month to avoid pressure drop caused by oil leakage; Calibrate
pressure sensors and tachometers quarterly to ensure accurate parameters;
Conduct a comprehensive inspection of the roller body every six months. If
uneven wear occurs, adjust the feed distributor to ensure even material
dropping. By implementing the above measures, the crushing ratio can be
increased to over 10:1, the service life of the roller surface can be extended
to over 400 hours, and production costs can be significantly reduced. If there
are still problems, it is recommended to contact the manufacturer to test the
compatibility between the roller surface pattern and the material, and optimize
the matching parameters of pressure and speed.