Sudden decline in productivity of quartz sand making equipment? Professional
manufacturers will help you troubleshoot the root causes
Sand making equipment is the core link in quartz sand production, and its
capacity directly determines the output efficiency of the whole production line.
Many quartz sand production enterprises have encountered such problems: the sand
production equipment operated normally the previous day, and the production
capacity suddenly declined sharply the next day (usually by more than 10% -
20%), which not only affects the delivery period, but also increases the energy
consumption and cost of unit product. As a professional manufacturer specialized
in the research, development and manufacturing of quartz sand making equipment
for more than ten years, we found that the sudden drop of sand making equipment
capacity was not accidental by combining a large number of field service
experience. It was mostly related to equipment parts, material characteristics,
operation specifications and other factors. As long as the steps were checked,
the root cause could be accurately found and quickly solved.
1、 First, clarify the specific performance of "capacity decline": avoid
misjudgment
Before troubleshooting, the authenticity of "capacity reduction" shall be
confirmed through data and phenomenon to avoid waste of time due to misoperation
or inspection deviation. It can be judged from three aspects:
Comparison of production data: record the current output of finished sand per
hour, and compare it with the rated capacity of the equipment (such as the rated
capacity of an impact sand making machine of 50-60t/h) and the average output of
the previous three days. If the output is lower than 80% of the normal level for
more than two consecutive hours, it can be judged as an abnormal decline of the
production capacity.
Equipment load change: Observe the ammeter reading of the sand making machine
motor. If the current does not decrease or even increase synchronously while the
output decreases, it indicates that the equipment may be in the "overload and
low production" state; If the current drops synchronously with the production,
blockage and wear may occur in the feed or in the equipment.
Discharging state of materials: check whether the material flow at the outlet
of sand making machine is uniform, whether there is "cutoff" or "caking"
phenomenon, and observe whether the amount of returns (materials returned to the
sand making machine after entering the screening machine) suddenly increases -
the abnormal increase of returns is often the direct signal of capacity
reduction.
2、 Stepwise troubleshooting: 5 core causes and targeted solutions
The capacity of quartz sand making equipment (taking the most widely used
impact sand making machine as an example) suddenly drops, which can be gradually
checked according to the sequence of "feeding → equipment interior → power
system → auxiliary device → material characteristics", and each step corresponds
to a clear solution.
(1) Step 1: Check the feeding system - "uneven feeding" is the most common
cause
The capacity of sand making machine is directly related to the stability of
feed volume. If the feed volume is variable or the feed mode is improper, it is
very easy to cause capacity fluctuation.
Possible cause 1: feeder failure or parameter imbalance
Phenomenon: the conveyor belt of the feeder slips or gets stuck, or the
vibration feeder has insufficient amplitude, resulting in intermittent materials
entering the sand making machine.
Solution: first check whether the feeder motor operates normally. If the
conveyor belt slips, adjust the tensioning device (such as tightening the
adjusting bolts of the conveyor belt roller); If the vibration feeder has a
small amplitude, the feeding amount can be increased by adjusting the angle of
the motor eccentric block (the larger the angle is, the larger the amplitude is.
It is suggested to adjust it to 45 ° - 60 °). Meanwhile, ensure that the feeder
is aligned with the feeding port of the sand making machine to avoid material
leakage.
Possible Cause 2: Oversize feed particle size or mixed large impurities
Phenomenon: there is "blockage accumulation" at the feeding port of sand
making machine, the equipment sends out a dull "buzzing" sound during operation,
and the motor current surges.
Solution: immediately shut down the machine and cut off the power supply, and
clean the blocked materials at the feed inlet with loader or special tools; The
particle size of the crushed raw materials shall be strictly controlled in the
following period (the particle size of the feed of the impact sand making
machine shall not exceed 30-50mm generally, which shall be subject to the
requirements of the equipment model). Meanwhile, a grid shall be installed above
the feeder (the mesh diameter of the grid shall be 5mm smaller than the maximum
feed size of the equipment) to intercept stones, metals and other foreign
matters to prevent blocking.
(2) Step 2: Disassemble and check the inside of the sand-making machine -
abrasion or blockage of core parts is "hard damage"
The impeller, impact block, liner plate and other parts inside the sand
making machine are directly involved in the material crushing. In case of wear,
blockage or looseness, the crushing efficiency will be directly reduced.
Possible cause 1: Impeller channel is blocked
Phenomenon: vibration intensifies during operation of the equipment, and the
proportion of "coarse particles" in the materials at the outlet increases. After
disassembly, it is found that the flow passage of the impeller is blocked by
fine quartz sand or caking materials.
Solution: disassemble the upper cover and impeller cover of the sand making
machine, and use a high pressure water gun (the water pressure shall be
controlled within 0.8-1.0MPa) to flush the blockage in the impeller flow
channel, especially the fine powder accumulation at the flow channel corner; If
the material humidity is high (moisture>6%), the drying link shall be added
before feeding to avoid caking and blocking of the material.
Possible Cause 2: Severe wear of impact block or liner plate
Phenomenon: the sand making machine makes abnormal sound of "metal impact"
during operation, the particle size of the crushed material becomes worse, and
the capacity gradually decreases (rather than sudden sudden drop, but when the
abrasion reaches the critical point, it will appear "cliff type" drop).
Solution: check the abrasion degree between the impact block (wear-resistant
component installed on the impeller) and the surrounding guard plate (liner
plate of inner wall of sand making machine). If the abrasion amount exceeds 1/3
of the original thickness, it shall be replaced immediately. It is suggested to
select the impact block made of high chrome alloy (the abrasion resistance is
more than 40% higher than that of ordinary high manganese steel). During
replacement, ensure that the connecting bolts between the impact block and the
impeller are tightened to avoid looseness during operation.
Possible cause 3: The impeller speed drops
Phenomenon: the motor operates normally, but the impeller rotates slowly, the
crushing strength is insufficient, and the "uncrushed particles" in the finished
sand increase.
Solution: check the transmission device between the motor and impeller (such
as belt and coupling). If the belt is loose and slipping, replace with a new
V-belt and adjust the tension; If the elastic pad of the coupling is damaged,
the elastic pad shall be replaced to ensure smooth power transmission. The
impeller speed shall strictly match the rated value of the equipment (such as
the rated speed of a sand-making machine of a certain model of 1500 r/min). If
the speed deviation exceeds 5%, the capacity will be significantly affected.
(3) Step 3: Troubleshoot the power system-low the capacity of the motor due
to "insufficient output"
The power core of sand making machine is the motor. If the motor fails, even
if there is no problem inside the equipment, the capacity will be reduced due to
insufficient power.
Possible cause 1: Unstable motor voltage or phase loss
Phenomenon: When the motor is running, it "buzzes", but the rotating speed
fails to rise, the ammeter pointer jumps greatly, and the motor is overheated
and trips in serious cases.
Solution: detect the voltage at the input end of the motor with a multimeter
to ensure that the three-phase voltage is stable within 380V ± 5%; If the
voltage fluctuates greatly, a voltage stabilizer shall be installed; If the
voltage of a phase is 0 (phase loss), check whether the wiring terminal in the
distribution box is loose and whether the contactor is faulty, and timely fasten
or replace the accessories.
Possible cause 2: damaged motor bearing or burnt winding
Phenomenon: the motor enclosure temperature is too high (over 70 ℃),
accompanied by "harsh abnormal sound" during operation, and the motor is easy to
trip when the capacity drops.
Solution: disassemble the motor end cover and check whether the bearing is
rusted or stuck. If damaged, replace the deep groove ball bearing of the same
model (it is suggested to use SKF, NSK and other high-quality brands) and apply
high-temperature resistant lithium base grease; If the motor winding is burned
(the insulation resistance is<0.5M Ω by megger), contact the professional
electrician to rewind the winding or replace the motor.
(4) Step 4: Check the auxiliary device - the "trailing leg" of the screening
and dust removal equipment
The capacity of sand making machine is also affected by the subsequent
screening equipment and dust removal equipment. If the auxiliary device fails,
it will cause "poor material circulation" and indirectly reduce the sand making
capacity.
Possible cause 1: screening machine is blocked or screen is damaged
Phenomenon: materials are piled up at the outlet of sand making machine, the
screening surface of screening machine is blocked by quartz sand, and the amount
of returns is far more than the normal level (the amount of returns is increased
by more than 50% compared with the normal value).
Solution: Clear the blockage on the screen surface of the screening machine.
If the screen is damaged, replace the wear-resistant polyurethane screen (more
resistant to quartz sand abrasion than the metal screen); At the same time,
adjust the inclination of the screening machine (15 ° - 20 ° is recommended) to
speed up the material screening speed and avoid the material from "flowing
backward" to the sand making machine after being stacked on the screen
surface.
Possible cause 2: excessive negative pressure of dust removal equipment
Phenomenon: the negative pressure inside the vortex chamber of sand making
machine is too high, and the fine materials are sucked into the dust removal
pipeline in advance, resulting in the decrease of finished sand output, and the
dust removal bag is easy to be blocked.
Solution: adjust the frequency conversion knob of the dedusting fan and
reduce the fan speed (the negative pressure should be controlled within - 500 to
- 800Pa); Check whether the dedusting bag is blocked, clean or replace it in
time to ensure that the dedusting system can not only remove powder, but also
not affect the normal crushing and discharging of materials.
(5) Step 5: analyze the material characteristics - the "changed sample" of
the raw material will also affect the production capacity
If there is no problem with the above equipment, it is necessary to consider
whether the characteristics of raw materials change, and the hardness, humidity
and particle size distribution of quartz sand will affect the sand making
efficiency.
Possible Cause 1: Sudden increase of hardness of raw material
Phenomenon: the motor current is normal, but the crushing strength of the
sand making machine is insufficient, the coarse particles in the finished sand
are increased, and the production capacity is reduced.
Solution: detect the Mohs hardness of raw materials (the Mohs hardness of
quartz sand is generally 7, if mixed with ores with higher hardness such as
granite, the parameters of sand making machine shall be adjusted) - reduce the
feeding amount (20% less than the normal amount), and properly increase the
impeller speed (5% - 10% increase within the rated range) to enhance the
crushing impact.
Possible cause 2: Too high humidity of raw material
Phenomenon: the materials are "caked and agglomerated" in the sand making
machine, the impeller is unable to eject the materials effectively, the
materials discharged from the outlet are caked, and the production capacity is
sharply reduced.
Solution: add drying equipment (such as roller drier) between raw material
bin and feeder to control material moisture below 5%; If there is no drying
equipment temporarily, the feeding amount can be reduced. Meanwhile, the
"anti-sticking liner" (made of PTFE) shall be installed inside the vortex
chamber of sand making machine to reduce the material bonding.
3、 Prevention is more than treatment: 3 measures to avoid sudden decline of
sand making equipment capacity
While solving the problem, daily prevention can greatly reduce the
probability of abnormal production capacity. It is suggested to start from the
following three aspects:
Establish the "daily inspection" system: check the operating state of the
feeder, impeller speed and motor voltage before startup of each shift, clean the
residual materials inside the sand making machine after shutdown, measure the
wear of the impact block and liner plate once a week, record in the Equipment
Maintenance Account, and prepare the goods in advance for replacement of
vulnerable parts.
Stabilize the characteristics of raw materials: sign an agreement with the
raw material supplier to ensure that the hardness, particle size and humidity of
the raw materials meet the requirements of the sand-making machine; If the raw
material batch is very different, "pre-screening" shall be carried out before
feeding to separate raw materials with different characteristics.
Regular calibration of equipment parameters: professional technicians shall
be invited to calibrate the impeller speed, feeding amount, inclination of the
screening machine and other parameters of the sand-making machine every quarter
to ensure that the equipment is always in the "optimal operation state" - for
example, by adjusting the clearance between the vortex chamber and impeller
(usually 8-15mm), the productivity can be maximized while ensuring the particle
size.
As a professional manufacturer of quartz sand sand making equipment, we not
only provide customers with sand making machines (customized from 10t/h small
equipment to 100t/h and above large equipment) suitable for different production
capacity requirements, but also provide full-cycle technical support of
"equipment installation - commissioning - maintenance". In case of capacity
reduction or other failures of your sand making equipment, please contact our
24-hour technical hotline at any time. We will help you quickly recover the
capacity through video guidance or on-site service. At the same time, we can
also provide the "equipment upgrading and transformation" scheme according to
your production situation, and further improve the stability and capacity limit
of the sand making equipment by replacing the core components and optimizing the
process.