Abnormal vibration and noise of quartz sand crushing equipment?

Abnormal vibration and noise of quartz sand crushing equipment? Professional manufacturers offer you fast positioning solution

Crushing equipment is the "throat" of quartz sand production line. Jaw crusher, cone crusher and other equipment are prone to abnormal vibration and abnormal sound when operating under high load and strong impact environment for a long time. Such problems seem to be common, but in fact, they have hidden dangers - in light, they lead to accelerated wear of parts, reduced productivity, in serious cases, they lead to serious failures such as equipment body cracking and motor burning, and even threaten the safety of operators. As a professional manufacturer specialized in R&D and manufacturing of quartz sand crushing equipment, we have combined the operation and maintenance cases of thousands of equipment to find out the core causes of abnormal vibration and abnormal sound and systematic solutions to help enterprises quickly eliminate hidden dangers.

First, define "abnormal signal": different performance corresponds to different faults

The vibration and abnormal sound of the crushing equipment is not a single mode. First judge the signal characteristics through the sense and instrument to narrow the troubleshooting scope:

High-frequency sharp abnormal sound+slight vibration: mostly related to friction and loosening of metal parts, such as loosening of liner bolts and oil shortage of bearing;

Low-frequency dull abnormal sound+violent body vibration: it may be caused by material jam, rotor imbalance or foundation looseness, which is commonly seen as material jam in the crushing cavity of jaw crusher and eccentric shaft failure of cone crusher;

Periodic "click" sound+intermittent vibration: rotating parts are mostly clamped with foreign matters or locally worn, such as impeller clamped with metal block and pulley keyway worn;

Increased vibration+abnormal sound at startup: mostly related to excessive startup load and assembly deviation of parts, such as material accumulation at feed inlet and misalignment of coupling.

It is suggested to equip vibration detector (measuring vibration acceleration and speed) and stethoscope every day, record the reference value of parameters during normal operation of the equipment (such as normal vibration speed of jaw crusher ≤ 4.5mm/s), and shut down the machine immediately for troubleshooting when the value exceeds 30% of the reference value or there is abnormal sound.

Step 1: Troubleshoot materials and feeds – "Source fit" is the basis

The hardness, particle size and feeding mode of quartz sand directly affect the stress state of crushing equipment. Unreasonable material input is the primary cause of abnormal vibration.

Oversize feed particle size or mixed with hard materials

Problem performance: The equipment suddenly makes "crash" sound during operation, the machine body vibrates violently, materials overflow from the feed inlet, and the motor trips in serious cases. The hardness of quartz sand is up to Mohs Level 7. If mixed with hard objects such as granite and metal blocks, or the feed particle size exceeds the rated upper limit of the equipment (for example, the size of the feed inlet of the jaw crusher is 500mm, but mixed with stones over 600mm), the crushing cavity will be subject to uneven stress and vibration and abnormal sound.

Troubleshooting method: Open the observation window at the feed inlet after shutdown and check whether there is foreign matter clamping stagnation; Measure the particle size of the uncrushed raw material with a tape measure and compare it with the "maximum feed particle size" marked in the equipment specification.

Solution: immediately shut down the machine and cut off the power supply, use a hydraulic jack to open the crushing chamber (jaw crusher) or disassemble the feed inlet (cone crusher), and clean the stuck hard materials and over-standard materials; Install a grid at the feed inlet (the grid aperture is 20-30mm smaller than the maximum feed particle size), and provide a metal detector to intercept foreign matters in advance; The upstream crushing process shall be adjusted to ensure that the particle size of raw materials entering the equipment meets the requirements.

Uneven or unbalanced feed

Problem performance: the equipment vibration is "periodic fluctuation", the abnormal sound is light and heavy, and the discharge particle size is coarse and fine. If the feeder feeds materials to one side of the crushing chamber, the stress of the equipment will be unbalanced, and the main shaft, eccentric shaft and other parts will bear eccentric load and cause vibration; More and less feeding will cause "idling - overload" alternation of the equipment, and increase the wear and vibration of parts.

Troubleshooting method: Observe the operating state of the feeder and check whether the materials evenly fall into the center of the crushing chamber; Monitor the motor current with an ammeter. If the current fluctuation exceeds 15% of the rated value, it indicates that the feed is uneven.

Solution: adjust the feeder parameters, such as the amplitude and frequency of the vibrating feeder, or the deviation adjustment device of the belt conveyor, to ensure that the materials are evenly distributed along the width direction of the crushing chamber; Install the feed flow sensor to form closed-loop control with the feeder, and automatically adjust the feed speed when the feed volume fluctuates; For jaw crusher, a distributing plate can be installed at the feed inlet to guide the materials evenly into the crushing chamber.

Step 2: Disassemble and check the core components - "internal loss" is the key

Wearing, looseness or assembly deviation of core parts such as lining plate, bearing and main shaft of crushing equipment is the main "internal cause" of abnormal vibration, which shall be accurately checked after disassembly.

Worn or loose liner/breaker

Problem performance: When the equipment is running, it sends out "metal friction" or "high frequency vibration", the vibration increases with the running time, and the particle size of the finished product becomes coarse. Liner plate (jaw crusher) and crusher hammer (impact crusher) are the parts directly contacting with materials. The surface is uneven after long-time wear or the fixing bolts are loosened, which will cause uneven stress during crushing and vibration; If the lining plate is severely worn on one side, it will cause unbalance load of equipment.

Troubleshooting method: Open the equipment access door after shutdown, check the surface abrasion of lining plate/crushing hammer, and measure the abrasion amount (replace it if exceeding 1/3 of the original thickness); Use a wrench to check whether the fixing bolts are loose, and observe whether the liner plate is fitted with the crushing chamber wall.

Solution: replace the liners/hammers with excessive wear and select high chrome alloy materials (the wear resistance is more than 50% higher than that of ordinary high manganese steel); During installation, elastic gasket shall be installed between liner plate and crushing chamber wall, and bolts shall be fastened evenly (tightened in diagonal order, with torque meeting equipment requirements); In case of wear on one side, check the feed for eccentric load and install new liner after adjustment.

Damaged bearing or lubrication failure

Problem performance: the temperature of the equipment bearing suddenly rises (over 70 ℃), accompanied by "sanding" friction sound or "gurgling" abnormal sound, and the vibration is concentrated at both ends of the main shaft. Bearing is the "rotating hub" of crushing equipment. Quartz sand production is characterized by much dust and heavy load. If the lubricating grease is insufficient, deteriorated or mixed with dust, the bearing ball will be worn, the raceway will be scratched and vibration will be caused; In serious cases, the bearing gets stuck and the motor is burned directly.

Troubleshooting method: detect bearing temperature with infrared thermometer and compare with normal operating temperature (generally ≤ 65 ℃); Open the bearing end cover and observe the status of lubricating grease (it is light yellow uniform paste in normal condition. If it turns black, caking or metal debris is found, the lubrication fails); Rotate the main shaft by hand and feel whether there is jamming or abnormal sound.

Solution: Thoroughly clean the bearing cavity and replace with new high-temperature lithium base grease (the filling amount is 1/2-2/3 of the bearing cavity volume); If the bearing is worn (the ball has pockmarks and the raceway is scratched), the bearing of the same model shall be replaced (it is recommended to select SKF, NSK and other brands). During installation, ensure that the fit clearance between the bearing and the main shaft meets the requirements (generally 0.02-0.05mm); Install the bearing dust cover and supplement the lubricating grease regularly (every 500 hours) to avoid dust intrusion.

Bent or unbalanced main shaft/eccentric shaft

Problem performance: the equipment has "violent low frequency vibration", the body shakes obviously, the abnormal sound is dull and continuous, and the base bolts are loose in serious cases. The main shaft (cone crusher) and eccentric shaft (jaw crusher) bear the main load of equipment operation, and the shaft body is easy to bend in case of long-term overload and impact of feed hard objects; Or the installation of parts on the shaft (such as belt pulley and flywheel) is eccentric, causing the rotor to be unbalanced and causing vibration.

Troubleshooting method: detect the radial run-out of the main shaft/eccentric shaft with a dial indicator (normal run-out ≤ 0.03mm) and judge whether it is bent; Check the balance state of the rotor assembly with the dynamic balance instrument after removing the belt pulley. If the unbalance exceeds 0.5g ・ m, it indicates that there is an imbalance problem.

Solution: if the shaft body is slightly bent (bending amount ≤ 0.1mm), it can be repaired by mechanical straightening; In case of serious bending or crack on the shaft body, the shaft must be replaced with a new one (40CrNiMo alloy steel with higher strength is selected); Re-install the parts on the shaft to ensure that the mounting surface fits closely, and accurately position with locating pins to avoid eccentricity; Calibrate the dynamic balance of the rotor assembly, drill holes or add counterweight on the counterweight block until the unbalance reaches the standard.

Step 3: Check the equipment installation and foundation - "external fixation" is the guarantee

The installation accuracy and foundation stability of the crushing equipment directly affect the operating state. Improper installation or foundation aging will cause continuous vibration and abnormal sound.

The equipment is not installed horizontally or the coupling is not aligned

Problem performance: overall vibration of the equipment during operation, "harsh abnormal sound" at the coupling between the motor and the main machine, overheating of the coupling protective cover and slipping of the belt pulley. Excessive levelness deviation (more than 0.2mm/m) during equipment installation will lead to uneven stress on the main shaft; Misalignment of coupling between motor and main machine (radial deviation>0.1mm or angular deviation>0.5 °) will generate additional torque and cause vibration and abnormal sound.

Troubleshooting method: check the levelness of equipment base with a level (measure in front and back, left and right directions); Remove the protective cover of the coupling, measure the radial and axial clearance of the two halves of the coupling with a feeler gauge, and judge the alignment.

Solution: adjust the adjusting bolt of the equipment base and insert the oblique iron until the levelness meets the standard; By moving the motor position, adjust the coupling centering - first calibrate the radial deviation (align the excircles of the two coupling halves), then calibrate the angular deviation (make the end faces parallel), and finally fasten the foundation bolts of the motor; Replace the worn elastic pad of the coupling to ensure stable power transmission.

Loose foundation or aged concrete

Problem performance: When the equipment is operating, the ground is vibrating, the base bolts are loose, and even "ground crack" occurs. The vibration and abnormal sound are aggravated with the increase of load. The impact force generated by the crushing equipment during operation is large. If the foundation concrete strength is insufficient (lower than C30), the reinforcement configuration is insufficient, or the concrete is aged and weathered after long-term use, the foundation will be sunk and cracked, and the fixing effect on the equipment will be lost.

Troubleshooting method: check whether the foundation bolts of the equipment are loose, and observe whether the vibration is relieved after re-tightening with a torque wrench; Check whether there is crack or peeling on the foundation surface. Check the concrete strength with a rebound tester to determine whether it is aged.

Solution: install lock washer for loose anchor bolt and fasten it according to rated torque (generally 200-300N ・ m); If the foundation is slightly cracked, epoxy resin grout can be injected for repair; When the crack is serious or the concrete strength is insufficient, the foundation needs to be re-cast. The concrete above C35 shall be selected to increase the density of reinforcement. The foundation depth shall not be less than 1/2 of the equipment height. The equipment can be installed above the concrete after 28 days of curing after pouring.

Step 4: Troubleshoot the transmission and power system - the "power transmission" shall be smooth

Failure of the transmission system (belt, coupling) and power system (motor) will lead to poor power transmission, vibration and abnormal sound.

Loose, off tracking or worn belt

Problem performance: When the equipment is running, the belt pulley sends out "abnormal slipping sound", the vibration increases with the belt run-out, the motor speed is normal but the host speed is insufficient. If the belt tension is insufficient, it will cause slipping; Inconsistent belt length or worn pulley groove may cause belt deviation; When the belt is aged and cracked, the power transmission is unstable, which will produce vibration and abnormal sound.

Troubleshooting method: press the middle of the belt with fingers. If the subsidence exceeds 15mm, it indicates that the tension is insufficient; Observe the running track of the belt. If it deviates from the belt pulley side, there is deviation; Check whether there is crack or slag on the belt surface and measure the belt thickness (replace the belt if the wear exceeds 20% of the original thickness).

Solution: adjust the belt tensioning wheel, increase the belt tension, and ensure the sinking amount is within 10-15mm; Replace the belt with inconsistent length or worn belt, and select the V-belt matched with the belt pulley groove (such as Type A and Type B); If the pulley groove is worn, repair or replace the pulley by turning, and ensure that the two pulley axes are parallel during installation.

Motor failure or unstable power supply

Problem performance: When the equipment is started, the vibration is fierce, the motor sends out "buzzing" abnormal sound, the current fluctuates greatly during operation, and even trips. Motor bearing damage, winding short circuit, or unstable power voltage and phase loss will lead to unstable motor output power, unbalanced power transmission and equipment vibration.

Troubleshooting method: detect the insulation resistance of the motor winding with a multimeter (normally ≥ 0.5M Ω) and judge whether there is short circuit; Detect the temperature of motor bearing with infrared thermometer and listen to whether the motor operates normally; Measure the power voltage with a voltmeter and observe whether it is stable within 380V ± 5% and whether there is phase loss.

Solution: replace the damaged motor bearing or repair the winding, and replace the new motor in serious cases; Equip the equipment with voltage regulator to ensure stable voltage; Check the contactor and circuit breaker in the distribution box, replace the faulty accessories and eliminate the phase loss problem.

Preventive measures: Reduce the occurrence rate of abnormal vibration

Establish "three-level patrol inspection" system: the operator shall check the feed inlet, belt and anchor bolts before startup of each shift; The maintenance personnel shall disassemble and check the lining plate, bearing and lubricating grease every week; Technicians shall use vibration detector and dynamic balance instrument for accurate detection every month and record Equipment Health Account.

Optimize material pretreatment: add ore washing and screening processes before crushing to remove clay and impurities, control the particle size and humidity of raw materials (water ≤ 5%) and reduce equipment blockage and wear.

Regular maintenance of core parts: according to the requirements of the equipment specification, replace the liner plate, breaking hammer and other vulnerable parts every 1000 hours, supplement the lubricating grease every 500 hours, and calibrate the main shaft balance and coupling alignment every 2000 hours, so as to reduce the risk of failure from the source.

As a professional manufacturer of quartz sand crushing equipment, we not only provide jaw crusher and cone crusher with different capacities (customized from 10t/h to 200t/h), but also provide the whole chain service of "installation and commissioning - operation and maintenance training - emergency repair". If your equipment experiences abnormal vibration and noise, please contact our 24-hour technical team at any time. We will quickly locate the problem through video guide or field service. At the same time, we can provide equipment upgrading schemes (such as installing intelligent vibration monitoring system and upgrading wear-resistant lining plate) according to your production pain points, so as to fundamentally improve the stability and service life of the equipment.