An open-pit factory in Shandong Province has long focused on coal processing and transshipment business. With the advancement of its production capacity upgrading plan, it is in urgent need of building a dedicated bulk material conveying line from the coal storage area to the processing workshop. The core material to be conveyed is bituminous coal (with a moisture content of 8%-12%, particle size of 0.5-10mm, and a small amount of coal dust prone to airborne dispersion). However, the traditional belt conveyors used previously have exposed numerous bottlenecks, which have become obstacles to production capacity expansion and environmental compliance.

Open-air conveying with an exposed structure leads to massive dispersion of coal dust, with a dust emission concentration of 35mg/m³—far exceeding the 15mg/m³ limit specified in the Integrated Emission Standard of Air Pollutants (GB16297-1996)—resulting in frequent complaints from surrounding residents. Meanwhile, the dispersion and spillage of coal dust cause a coal loss rate of 6%. After the factory's upgrading, it needs to achieve continuous conveying at 400 tons per hour. However, affected by open-air temperature differences (a high of 40℃ in summer and a low of -10℃ in winter), the traditional equipment is prone to belt slipping and idler seal failure, with an actual conveying efficiency of only 320 tons per hour, which fails to match the production load. The 1568-meter conveying route requires a 10-meter height lift (from the low-lying area of the storage area to the workshop feed inlet). Traditional belt conveyors require the setup of 2 transfer stations, which not only increases equipment investment by 30% but also causes secondary coal dust dispersion and loss during the transfer process. The original equipment is not optimized for open-air environments: rainwater seeps into the idlers during the rainy season, requiring the replacement of a batch of idlers every 3 months; low temperatures in winter cause the belt to harden and crack, resulting in persistently high annual maintenance costs.

Project Requirements and Objectives

The factory has put forward core requirements for the conveying system: "accurate parameters, scenario adaptation, compliance and reliability". Specifically: the conveying capacity shall be ≥400 tons per hour, the conveying length 1568 meters, and the lifting height 10 meters; the core equipment shall be a pipe belt conveyor with a pipe diameter of 350mm; the equipment shall withstand high temperatures, low temperatures, and rain erosion in open-air environments, and stably achieve heavy-load conveying with a 10-meter lifting height; the dust emission concentration shall be ≤10mg/m³, the service life of core components (idlers, pulleys) ≥50,000 hours, and operation training and a 2-year warranty shall be provided.

Based on these requirements, four project objectives are set:

1. Environmental Compliance: Control the dust emission concentration within 8mg/m³ and reduce the coal loss rate to below 1%;
2. Efficiency Matching: Achieve continuous conveying at 400 tons per hour without transfer;
3. Open-air Durability: Ensure an annual failure rate ≤1.5% in environments of -10℃~40℃ and rain, with core component service life exceeding 50,000 hours;
4. Cost Optimization: Reduce initial equipment investment by 20% and subsequent annual maintenance costs by 35%.

ZOOMRY's Customized Solution

Combining the terrain, meteorological conditions, and coal characteristics of the open-pit factory in Shandong, ZOOMRY has created a full-chain solution of "pipe belt conveyor + supporting auxiliary equipment + open-air dedicated parts", utilizing the technical advantages of pipe belt conveyors in "sealing, long-distance conveying, and heavy-load lifting".

Core Equipment

Targeting a capacity of 400 tons per hour, 350mm pipe diameter, 1568-meter belt length, and 10-meter lifting height, ZOOMRY has custom-produced a set of pipe belt conveyors. Multiple sets of staggered regular hexagonal idler groups are adopted to stably enclose the 1200mm-wide ST1250 pipe belt (with a tensile strength of ≥1250N/mm and excellent wear resistance) into a closed tubular shape with a 350mm diameter. The belt overlap reaches 120mm (10% higher than the national standard), completely blocking the coal dust dispersion path. Meanwhile, double-layer rubber sealing skirts (wear-resistant inner layer and dust-proof outer layer) are added to the head and tail of the conveyor, and cooperate with the non-powered dust collection chute with a built-in air flow buffer cavity at the discharge end, forming a three-layer dust-proof system of "idler group sealing + head-tail sealing + discharge buffering". Eventually, the dust emission concentration is controlled at 7.5mg/m³. The closed tubular structure also isolates rainwater, reducing the coal caking rate from 15% to below 0.5% during the open-air rainy season, while the coal loss rate is simultaneously reduced to 0.8%.

In terms of power and lifting, the "head dual-drive" design is adopted, equipped with two 250kW variable-frequency motors (total power of 500kW, protection class IP55) and matched with a hardened gear reducer (transmission efficiency ≥96%), which can adjust the speed in real time according to the coal conveying volume to avoid overload. The hydraulic tensioning device automatically compensates for the thermal expansion and contraction of the belt caused by open-air temperature differences, ensuring that the belt in the lifting section does not slip and stably completes the 10-meter height conveying. The belt speed is set to 2.8m/s, and the feeding volume is adjusted through a PLC-linked feeding system, ensuring a continuous conveying efficiency of 400 tons per hour.

For open-air durability, the idlers are ZOOMRY's independently produced "open-air dedicated HDPE idlers", featuring a smooth and wear-resistant surface, a temperature resistance range of -20℃~60℃, and water intake ≤95g in a 72-hour immersion test (better than the enterprise standard of 100g), effectively preventing rust caused by rainwater. The pulleys are made of 40Cr forged material (diameter 159mm); after thermal spraying wear-resistant treatment on the surface, their wear resistance is increased by 50%, with a service life exceeding 50,000 hours. The conveyor frame adopts a hot-dip galvanizing process, with a rust resistance grade of Zn12 in GB/T 13912-2002, adapting to the open-air humid environment.

Supporting Auxiliary Equipment

To achieve seamless connection of coal from storage to processing, the solution is equipped with the ZR120D hopper feeder independently developed by ZOOMRY. Installed at the feed end of the pipe belt conveyor, it is connected to the discharge hopper in the coal storage area. The hopper capacity is 6m³ (20% larger than the standard model, adapting to the open-air intermittent coal unloading rhythm), and it is equipped with an 18.5kW variable-frequency speed-regulating motor, which can adjust the feeding volume in real time according to the conveyor's operation status to avoid coal accumulation and blockage. The inner wall of the hopper is paved with a 12mm-thick wear-resistant ceramic liner to resist coal wear, and a color steel plate rain shelter is added to prevent rainwater from entering and causing coal caking.

The cleaning and protection system is equipped with 2 sets of PU material cleaning scrapers (1 set at the head and 1 set at the tail), with a fitting degree of ≥95% with the pipe belt, effectively removing residual coal dust on the belt surface and avoiding belt deviation caused by material adhesion. A detachable transparent PC Rain Cover is installed on the top of the conveyor, which not only facilitates open-air inspection but also shields against rain and sun exposure to extend the belt's service life. At the same time, a belt deviation switch is equipped, which automatically alarms and shuts down when the deviation exceeds 5mm, ensuring operation safety during open-air unattended operation.

Core Component Guarantee

All components are independently researched, developed and produced by ZOOMRY, with performance superior to national and industry standards. Quiet idlers with a diameter of 133mm are selected for key parts, with radial runout ≤0.4mm and rotational resistance ≤2N (both better than national standards), reducing motor energy consumption. The pulleys undergo CNC four-roll rounding processing (ovality ＜1.5mm); after welding, they undergo ultrasonic flaw detection and tempering stress relief treatment to ensure no internal cracks, adapting to open-air heavy-load conveying. The non-powered dust collection chute reduces discharge dust through an air flow buffer design; the ST1250 pipe belt is added with an anti-ultraviolet aging agent to avoid embrittlement due to open-air sun exposure; all electrical components are of explosion-proof type complying with GB 3836.1-2010, adapting to the coal dust environment and reducing safety risks.

Project Implementation

Preliminary Survey

ZOOMRY dispatched a 5-person technical team to the open-pit factory in Shandong, and completed three tasks within 12 days:

1. Surveying the 3D terrain of the 1568-meter conveying route using a total station, accurately marking the slope of the 10-meter lifting section (average slope 0.64%) and the drainage status of the open-air operation area, and optimizing the installation height of the conveyor frame to avoid waterlogged areas in the rainy season;
2. Collecting coal samples and testing their fluidity and wear resistance in the laboratory to determine the idler spacing and belt tension parameters;
3. Combining local meteorological data (high temperature, low temperature, and rainy season distribution) to formulate a special open-air equipment protection plan (such as rain cover layout and motor heat dissipation optimization).

Equipment Production

All equipment and components are produced at ZOOMRY's Hebei factory, and the entire process is integrated into the ISO 9001 quality management system. The pulleys of the pipe belt conveyor must pass a 24-hour static load test with 1.2 times the rated load, and are qualified only if there is no deformation; the idlers undergo a 1000-hour no-load trial operation to verify their sealing performance and rotational resistance; the ST1250 pipe belt leaves the factory only after completing tensile and wear tests. The factory sent representatives to the factory for acceptance, and the open-air durability test results (high-low temperature cycle test, rain test) of the equipment were excellent, with all parameters meeting the contract requirements.

Installation and Commissioning

ZOOMRY dispatched an 8-person installation team to the site and adopted the "modular splicing + rainproof construction" mode. The main body of the pipe belt conveyor is divided into 10 sections (each about 150-160 meters), which are pre-assembled in the factory, and only bolt connection and belt vulcanization are required on-site, with an installation cycle of only 32 days (industry average is 45 days). During rainy days, temporary rain shelters are used to cover the equipment to prevent rust.

During the commissioning phase, a 72-hour full-load trial operation is conducted to simulate open-air working conditions (day-night temperature difference, sunlight, etc.), optimizing PLC parameters to stabilize the conveying efficiency at 405 tons per hour. Meanwhile, the problem of idler spacing deviation in the lifting section is solved, and the idler positions are adjusted on-site to ensure no belt deviation.

Operation and Maintenance Training

ZOOMRY provided 15-day special training for 4 operation and maintenance personnel of the factory. The training content covers daily inspection of open-air equipment (idler rotation, rain cover sealing, motor temperature, etc.), common fault handling (belt slipping, idler jamming), regular maintenance (idler lubrication, belt tension adjustment), and special skills for open-air environments (rainy season drainage inspection, winter belt preheating operation). After training, the operation and maintenance team can independently complete equipment operation and basic maintenance.

Project Results

Since the project was put into operation, it has operated stably for a long time, with all indicators exceeding expectations, creating significant value for the open-pit factory in Zaozhuang City. In terms of environmental protection and material utilization, the dust emission concentration has decreased from 35mg/m³ to 7.5mg/m³, far exceeding national standards, which completely resolves the risks of resident complaints and environmental penalties. The coal loss rate has dropped from 6% to 0.8%; based on an annual conveying volume of 2.8 million tons (the factory's actual production capacity), it reduces losses by 20,200 tons per year, greatly improving material utilization. At the same time, the transfer-free design reduces the land occupation of 2 stations, increasing the factory's site utilization rate by 25%. In terms of production capacity, it realizes 1,568-meter continuous conveying without transfer, with an actual efficiency stably maintained at 405 tons per hour, fully meeting the needs of production capacity upgrading. The conveying cycle has been shortened from 5 hours (of the traditional solution) to 3.7 hours, reducing the annual production downtime caused by insufficient conveying by approximately 40 hours and indirectly increasing production capacity value. The core components of the equipment (idlers, pulleys) have operated stably for a long time, requiring only regular replacement of belts and scrapers, and the annual maintenance cost is 40% lower than that of traditional equipment. In the open-air environment of -10℃~40℃, the annual failure rate is only 1.2%, which is lower than the target of 1.5%, and no major failures have occurred due to extreme weather or rain. When the factory conducts a second production capacity upgrade, it only needs to fine-tune the power of the drive unit (from 500kW to 550kW) to meet the new demand of 450 tons per hour, fully demonstrating the equipment's scalability and durability.

The factory's project manager said: "ZOOMRY's pipe belt conveyor not only solves the problems of environmental protection and efficiency, but also can operate stably in the open-air environment for a long time. We will still give priority to ZOOMRY's solutions for future expansion."

Core Advantages of ZOOMRY

1. Fast Customization Response: International brands require a design cycle of more than 6 months for special open-air needs, while ZOOMRY, relying on its independent R&D team, can complete open-air optimization design (such as exclusive configurations like HDPE idlers and hot-dip galvanized frames) in only 2 months, which is more in line with scenario needs.
2. Independent Component Production: ZOOMRY independently produces core components such as idlers, pulleys, and belts, with parameters adjustable according to project needs (such as the sealing performance of open-air idlers and the wear resistance of pulleys). Its quality complies with ISO 9001 and CEMA standards, with better adaptability and stability.
3. Full-Process Services: ZOOMRY holds international certifications such as ISO 9001, ISO 14001, CE, and EAC, and its equipment meets compliance requirements in different regions around the world. It provides full-process services from surveying to lifelong operation and maintenance; overseas customers can rely on global spare parts warehouses and multilingual support to solve operation and maintenance pain points.