To prevent material blockages in manufactured sand equipment, six key factors must be addressed: material properties, feed control, equipment configuration, wear part maintenance, operational standards, and voltage stability. Below is a detailed analysis:
I. Material Property Control
Moisture Management: High-moisture materials readily adhere to the inner walls of the crushing chamber, leading to blockages. Take coal—a typical viscous material—as an example: when its moisture content is high, a sticky layer forms during crushing. This layer not only impedes normal crushing but also causes subsequent material to adhere to it, further exacerbating blockages. Production data indicates that when moisture exceeds 15%, the probability of coal-based material blockages increases significantly. The solution involves grading the material, separating highly adhesive, moisture-rich sticky materials from drier, block-like materials. For highly moist materials, preheating or drying treatments can be applied. For instance, using a hot air dryer to reduce moisture content below 8% effectively minimizes blockage occurrences.
Particle Size Control: Oversized or excessively hard materials increase crushing difficulty, triggering blockages. For example, feed exceeding the equipment's maximum input size entering the crusher unbroken can become lodged within the crushing chamber. In a case study at a sand and gravel plant, a batch of material mixed with excessive rocks exceeding the equipment's feed size caused frequent blockages within a short period, significantly reducing production efficiency. The solution involved screening the material before entering the sand maker. Using equipment like vibrating screens, oversized particles were pre-crushed to ensure compliance with the equipment's feed requirements. Generally, feed particle size should be controlled within 80% of the equipment's maximum feed size.
II. Feed Rate Optimization
Uniform Feeding: Excessively fast feed rates cause material buildup in the crushing chamber, increasing equipment load. For example, when feed rate exceeds processing capacity, material rapidly fills the chamber, obstructing discharge. At a small sand production plant, improper operator handling resulted in excessively high feed rates, causing frequent equipment blockages during operation and severely impacting production schedules. The solution involved adopting vibrating feeders. These devices achieve uniform, continuous feeding by adjusting amplitude and frequency, preventing material buildup. Field tests demonstrated that using vibrating feeders reduced equipment blockage rates by approximately 30%.
Speed Matching: Feeding speed must align with equipment processing capacity. For instance, variable frequency drives (VFDs) regulate motor speed to control vibrating feeder output, ensuring feeding pace matches processing capability and preventing overload. At a large sand production facility, implementing VFD technology enabled dynamic adjustment of feeding speed based on real-time processing capacity, significantly enhancing operational stability and substantially reducing blockages. Statistics indicate that comprehensive equipment efficiency increased by 15% after implementing variable frequency control.
III. Equipment Configuration Rationality
Belt Conveyor Capacity Matching: When belt conveyor capacity exceeds the crushing capacity of the sand-making machine, materials rapidly flood into the crusher, causing delayed crushing and blockages. For instance, when belt conveyor capacity exceeds the equipment's crushing capacity by 20%, the risk of blockages significantly increases. At a medium-sized sand and gravel plant, mismatched conveyor belt capacity design relative to the sand-making machine's crushing capacity frequently caused blockages. The solution involves rationally configuring belt conveyor capacity based on the equipment's crushing capacity to ensure coordinated material transport and crushing speeds. Generally, belt conveyor capacity should be controlled between 90% and 110% of the equipment's crushing capacity.
Discharge Opening Adjustment: Improper discharge opening adjustment affects material discharge speed. For example, an excessively small discharge opening causes slow material discharge and accumulation within the crushing chamber. In a sand-making workshop, an excessively small discharge opening caused material buildup in the crushing chamber, resulting in equipment blockage and disrupted production. The solution involves adjusting the discharge opening size appropriately based on material characteristics and production requirements to ensure smooth material discharge. In practice, the optimal discharge opening size can be determined by observing material discharge patterns and equipment operating conditions, then gradually adjusting the opening size.
IV. Wear Parts Maintenance
Wear Monitoring: Severe wear on wear parts increases friction between materials and equipment components, preventing timely material discharge. For example, worn hammers, liners, and other wear parts reduce crushing efficiency, prolonging material residence time in the crushing chamber and increasing the risk of blockages. At one sand production plant, failure to replace severely worn hammer heads promptly caused a significant drop in crushing efficiency. Material accumulated in the crushing chamber, ultimately triggering a blockage. The solution involves regularly inspecting wear part conditions, establishing a wear monitoring log to record usage time and wear levels. When wear reaches a certain threshold, promptly replace severely worn components. Generally, hammer heads should be replaced when wear exceeds 30% of their original dimensions.
Lubrication Maintenance: Lubrication system failures can cause operational disruptions and increase blockage risks. For instance, insufficient lubricant or degraded oil quality accelerates component wear, compromising crushing performance. At a sand production facility, inadequate lubrication system maintenance—characterized by insufficient oil levels and degraded oil quality—resulted in severe component wear and frequent material jams. The solution involves regular lubrication system inspections to ensure adequate, clean lubricant and selecting oil suitable for the equipment's operating conditions. Typically, lubricant conditions should be checked every 500 operating hours, with oil replacement every 2000 hours.
V. Operational Standards
Operator Training: Personnel unfamiliar with equipment principles and procedures may cause blockages through improper operation. Examples include misadjusting feed rates or discharge ports. At a newly commissioned sand production plant, operators lacking systematic training and proficiency in equipment operation repeatedly caused blockages during production due to improper handling. The solution involves providing systematic training covering equipment principles, operational procedures, maintenance knowledge, and emergency response methods. This training enables operators to master equipment operation skills, reducing blockages caused by operational errors.
Emergency Response: Develop a blockage emergency response plan specifying shutdown, clearance, and restart procedures. For example, upon detecting a blockage, immediately halt the machine and clear material from the crushing chamber to prevent equipment damage and production interruptions. At a sand production workshop, a detailed emergency clogging response plan was implemented, with regular drills conducted for operators. When actual clogging occurred, operators swiftly executed the plan, minimizing equipment downtime and reducing production losses.
VI. Voltage Stability
Voltage Monitoring: Low or unstable voltage can cause abnormal equipment operation, leading to clogging. For instance, low voltage reduces motor speed and crushing force, preventing timely material fragmentation and discharge. At a remote sand plant, frequent blockages occurred due to unstable local grid voltage. The solution involved installing voltage stabilizers to maintain supply within rated parameters, typically with accuracy controlled within ±5%.
Power Assurance: Coordinate with power authorities to guarantee stable electricity supply at the production site. For instance, during peak consumption periods, implement advance power scheduling to prevent voltage fluctuations from disrupting equipment operation. A large sand production enterprise established effective communication protocols with local power authorities. During high-demand periods, the power department adjusts supply according to the company's production requirements, ensuring uninterrupted equipment operation and minimizing blockages caused by voltage fluctuations.
