Pipe Belt Conveyor Solution for Bulk Coal Conveying

In recent years, a certain open-pit factory in China (specializing in coal processing and transshipment) launched a production capacity upgrading plan, requiring the construction of 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). At that time, the belt conveyor used by the factory had the following problems:

In the open-air environment, when the traditional open-type belt conveyor transported coal, coal dust escaped under wind influence, resulting in a dust emission concentration of 35mg/m³—far exceeding the 15mg/m³ limit specified in the Integrated Emission Standard of Air Pollutants (GB16297-1996) at that time. The factory received multiple complaints from surrounding residents, and the coal loss rate reached 6% (due to coal dust dispersion and spillage). After the factory’s upgrading, it needed to achieve continuous conveying of 400 tons per hour; however, affected by the open-air temperature difference (a high of 40℃ in summer and a low of -10℃ in winter), the traditional equipment was prone to belt slipping and idler seal failure, with an actual efficiency of only 320 tons per hour, which could not meet the production load. The total length of the conveying route was 1568 meters, requiring a 10-meter height lift (from the low-lying area of the storage area to the workshop feed inlet). Traditional belt conveyors needed to set up 2 transfer stations to realize lifting and steering, which not only increased equipment investment by 30% but also caused secondary coal dust emission and loss due to the transfer process. The original equipment was not optimized for the open-air environment: rainwater seeped into idlers during the rainy season, causing rust (a batch of idlers needed to be replaced every 3 months on average); low temperatures in winter made the belt harden and crack, leading to persistently high annual maintenance costs.

To solve the above problems, ZOOMRY set up a "Special Team for Open-Pit Coal Projects". Combining on-site survey data of the factory (open-pit terrain, meteorological records, coal characteristics) and after multiple rounds of solution iterations, it finally determined a full-chain solution of "core pipe belt conveyor + supporting auxiliary equipment + open-air dedicated parts". This solution gives full play to the advantages of pipe belt conveyors in "sealing, long-distance conveying, and heavy-load lifting", and accurately matches the project parameters and needs of open-air scenarios.

Project Overview

Core Project Requirements

The needs of the open-pit factory focus on three dimensions—"accurate parameters, scenario adaptation, and compliance & reliability"—which fully align with the industry characteristics of open-pit coal conveying. In terms of parameters, it clearly requires the conveying equipment to have a handling capacity of ≥400 tons per hour, a conveying length of 1568 meters, and a lifting height of 10 meters. The core equipment is a pipe belt conveyor (a category of belt conveyors) with a pipe diameter of 350mm (adapted to coal particle size to avoid blockage). In terms of scenario adaptation, the equipment must withstand high temperature, low temperature, and rain erosion in the open-air environment, and adapt to heavy-load conveying with a 10-meter lifting height. In terms of compliance and operation & maintenance, the dust emission concentration must be ≤10mg/m³, the service life of core equipment components (idlers, pulleys) must be ≥30,000 hours, and operation training and a 2-year warranty must be provided to ensure the factory’s operation & maintenance team can operate independently.

Core Project Objectives

Based on the requirements and combined with the production and environmental protection requirements of the open-pit factory, four project objectives were set:

1. Environmental Compliance: The dust emission concentration of the pipe belt conveyor system is controlled within 8mg/m³, and the coal loss rate is reduced to below 1%;
2. Efficiency Matching: Realize continuous conveying of 400 tons per hour without transfer to meet the factory’s production capacity upgrading needs;
3. Open-Air Durability: The annual failure rate of the equipment is ≤1.5% under the environment of -10℃~40℃ and rain, and the service life of core components exceeds 50,000 hours;
4. Cost Reduction: Compared with the traditional belt conveyor + transfer station solution, reduce initial equipment investment by 20% and subsequent annual maintenance costs by 35%.

Project Solution Equipment

Core Equipment

To meet the requirements of 400 tons per hour capacity, 350mm pipe diameter, 1568-meter belt length, and 10-meter lifting height, ZOOMRY customized and produced a set of pipe belt conveyors. Its design strictly follows the technical standards of pipe belt conveyors, with modifications made for the open-air environment:

• Sealing and Environmental Protection Design: The overall structure adopts a "hexagonal idler group", folding a 1200mm-wide ST1250 pipe belt (customer-specified model, with a tensile strength of ≥1250N/mm and excellent wear resistance) into a pipe shape with a diameter of 350mm. The belt overlap reaches 120mm (10% higher than the national standard), realizing fully sealed coal conveying. Rubber sealing skirts are added to the head and tail of the conveyor, and a non-powered dust collection chute is installed at the discharge end to effectively block coal dust escape. Finally, the dust emission concentration is controlled at 7.5mg/m³, far below compliance requirements. Meanwhile, the pipe structure prevents rainwater from directly contacting coal, solving the problem of coal caking in the open-air rainy season, and the coal loss rate is reduced to 0.8%.
• Power and Lifting Adaptation: To meet the needs of 10-meter lifting height and 1568-meter long-distance heavy-load conveying, a "head dual-drive" design is adopted, equipped with two 250kW variable frequency motors (total power of 500kW, protection class IP55) and a hardened gear reducer (transmission efficiency ≥96%). The speed can be adjusted in real time according to coal conveying volume to avoid overload. The belt tension control system uses a hydraulic tensioning device to automatically compensate for belt elongation (caused by thermal expansion and contraction of the belt due to open-air temperature differences), ensuring the belt in the lifting section does not slip and realizing stable conveying at a 10-meter height. The belt speed is set to 2.8m/s, and the feeding volume is adjusted through a PLC-linked feeding system to ensure continuous conveying efficiency of 400 tons per hour.
• Open-Air Durability Optimization: The idlers are ZOOMRY’s independently produced "open-air dedicated HDPE idlers", with a smooth and wear-resistant surface, temperature resistance range of -20℃~60℃, and water intake ≤95g in a 72-hour immersion test (better than ZOOMRY’s standard of 100g), preventing rust caused by rainwater. The pulleys are made of 40Cr forged material (diameter 159mm), and their surfaces are treated with thermal spraying for wear resistance—improving wear resistance by 50% and extending service life to over 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 Equipment

To ensure seamless connection of coal from the storage area to the processing workshop, the solution is equipped with 2 types of core auxiliary equipment synchronously—all independently developed by ZOOMRY, complying with technical specifications, and optimized for open-air scenarios:

• 1 set of ZR120D hopper feeder: Installed at the feed end of the pipe belt conveyor, 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 uses a variable frequency speed-regulating motor (power 18.5kW). The feeding volume can be adjusted 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 rain shelter (made of color steel plate) is added to prevent rainwater from entering the hopper and causing coal caking.
• Complete Cleaning and Protection System: Equipped with 2 sets of PU material cleaning scrapers (1 at the head, 1 at the tail). The fitting degree between the scrapers and the pipe belt is ≥95%, effectively removing residual coal dust on the belt surface and avoiding belt deviation caused by material adhesion. A detachable rain cover (transparent PC material) is installed on the top of the conveyor, which not only facilitates open-air inspection but also shields against rain and sun exposure, extending the belt’s service life. Meanwhile, 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 Components

All components are independently produced by ZOOMRY, with performance superior to national and industry standards, ensuring long-term stable operation in the open-air environment:

• Idlers and Pulleys: In addition to the aforementioned open-air dedicated HDPE idlers, quiet idlers (diameter 133mm) are used for key parts, with radial runout ≤0.4mm (better than the national standard of 0.5mm) and rotational resistance ≤2N (better than the national standard of 3N), reducing motor energy consumption. The pulleys undergo CNC four-roll rounding processing (ovality <1.5mm), and after welding, ultrasonic flaw detection and tempering stress relief treatment are performed to ensure no internal cracks, adapting to open-air heavy-load conveying.
• Other Auxiliary Components: A non-powered dust collection chute is used to further reduce discharge dust through air flow buffering design; the ST1250 pipe belt is added with an anti-ultraviolet aging agent to avoid belt embrittlement caused by open-air sun exposure; all electrical components are explosion-proof (complying with GB 3836.1-2010), adapting to the open-air coal dust environment and reducing safety risks.

Project Implementation

In the preliminary survey stage, ZOOMRY dispatched a 5-person technical team to the open-pit factory. It took 12 days to complete the 3D terrain data survey of the 1568-meter conveying route using a total station, accurately marking the slope of the lifting section (the 10-meter height corresponds to an average slope of 0.64%) and the drainage status of the open-air operation area, and optimizing the installation height of the conveyor frame (avoiding waterlogged areas in the rainy season). Coal samples were collected and tested for fluidity and wear resistance in the company’s laboratory to determine idler spacing and belt tension parameters. Combined with local meteorological data (high summer temperature, low winter temperature, and concentrated rainfall period in the rainy season), a special plan for open-air equipment protection was formulated (such as the installation position of the rain cover and optimization of motor heat dissipation).

In the production and manufacturing stage, all equipment and components were produced in ZOOMRY’s Hebei factory, with the entire process integrated into the ISO 9001 Quality Management System: The pulleys of the pipe belt conveyor were required to pass a 24-hour static load test (no deformation under 1.2 times the rated load); the idlers had to undergo a 1000-hour no-load trial operation to verify sealing performance and rotational resistance; the ST1250 pipe belt needed to undergo tensile and wear tests before leaving the factory. In the same year, the open-pit factory sent representatives to the factory for acceptance—all parameters met the contract requirements, and the results of the open-air durability tests (high-low temperature cycle test, rain test) were particularly excellent.

In the installation and commissioning stage, ZOOMRY dispatched an 8-person installation team to the site, adopting a "modular splicing + rainproof construction" mode based on the characteristics of open-air construction: The main body of the pipe belt conveyor was divided into 10 sections (each about 150-160 meters), pre-assembled in the factory in advance. On-site, only bolt connection and belt vulcanization were required, and the installation cycle was only 32 days (the industry average cycle is 45 days). The installation process avoided the rainy season; in case of rain, temporary rain shelters were used to cover equipment components to prevent rust caused by rainwater. During commissioning, a 72-hour continuous full-load trial operation was conducted to simulate the actual working conditions of the open-pit factory (high temperature during the day, low temperature at night), optimizing PLC program parameters to ensure the conveyor’s conveying efficiency was stably maintained at 405 tons per hour—exceeding the 400 tons per hour requirement. Meanwhile, the problem of "idler spacing deviation in the lifting section" found during installation was solved, and the idler positions were adjusted on-site to ensure no belt deviation during operation.

In the operation and maintenance training stage, ZOOMRY provided a 15-day special training for 4 operation and maintenance personnel of the factory. The training content covered daily inspection of open-air equipment (idler rotation status, rain cover sealing, motor temperature), common fault handling (belt slipping, idler jamming), and regular maintenance (idler lubrication cycle, belt tension adjustment), and a detailed operation manual was provided. In response to the special maintenance needs of the open-air environment, skills such as "equipment drainage inspection in the rainy season" and "belt preheating operation in winter" were specially trained to ensure the operation & maintenance team could independently complete equipment operation and basic maintenance after training.

Project Results

Since the official commissioning of the project, the equipment has operated stably for a long time, and all indicators have exceeded expectations. It has solved the core pain points of coal conveying for the open-pit factory and created significant economic and environmental value:

In terms of environmental protection and compliance: The fully sealed design of the pipe belt conveyor reduced the factory’s dust emission concentration from 35mg/m³ to 7.5mg/m³, far exceeding national and local standards. Since then, the factory has not received any more dust-related complaints and has avoided the risk of environmental penalties. The coal loss rate decreased from 6% to 0.8%; based on an annual conveying volume of 2.8 million tons (the factory’s actual production capacity), the annual loss is reduced by 20,200 tons. Calculated based on the market price of coal, the annual cost savings from material loss are significant. Meanwhile, the transfer-free design reduces the land occupation of 2 stations, increasing the site utilization rate of the open-pit factory by 25%.

In terms of efficiency and production capacity: The pipe belt conveyor realizes 1568-meter continuous conveying without transfer, with an actual efficiency stably maintained at 405 tons per hour, meeting the factory’s production capacity upgrading needs. Compared with the traditional belt conveyor + transfer station solution, the conveying cycle is shortened from 5 hours to 3.7 hours, reducing the annual production downtime caused by insufficient conveying by approximately 40 hours, and indirectly creating additional production value of over 3 million yuan (calculated based on the factory’s coal processing profit). The stable operation of the 10-meter lifting section completely eliminates secondary dust emission and loss in the transfer process, making the conveying process smoother.

In terms of reliability and open-air durability: The equipment has operated stably for many years, and no large-scale replacement of core components (idlers, pulleys) has been required—only regular replacement of belts and scrapers is needed. The annual maintenance cost is 40% lower than that of traditional equipment. In the open-air environment of -10℃~40℃, the annual failure rate of the equipment is only 1.2% (far lower than the 1.5% target), and no major failures have been caused by high temperature, low temperature, or rain. When the open-pit factory carried out a second production capacity upgrade, the pipe belt conveyor could meet the new requirement of 450 tons per hour through a simple power adjustment of the drive unit (from 500kW to 550kW), demonstrating the equipment’s scalability and durability.

The person in charge of the open-pit factory’s project said during equipment inspection: "ZOOMRY's pipe belt conveyor not only solved our environmental protection and efficiency problems back then, but also can operate stably in the open-air environment for many years—this is more durable than the equipment we used before. When the factory expands in the future, we will still give priority to ZOOMRY's solutions."

ZOOMRY's Advantages

• Stronger Customization: Most international brands provide standardized pipe belt conveyor products, and their design cycle for special needs such as open-air high temperature, low temperature, and rain exceeds 6 months; relying on its independent R&D team, ZOOMRY completed the open-air optimization design of the equipment in only 2 months, with exclusive configurations such as HDPE idlers, hot-dip galvanized frames, and rain covers, which are more in line with the actual needs of open-air scenarios.
• Independent Core Component R&D: ZOOMRY independently produces core components such as idlers, pulleys, and belts, and can adjust parameters 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. Compared with brands relying on external procurement, its components have better compatibility and more stable quality—which is the key to the equipment’s long-term open-air operation.
• End-to-End Service Support: ZOOMRY holds international certifications such as ISO 9001, ISO 14001, CE, and EAC, and its equipment can meet compliance requirements in different regions around the world, adapting to the "both domestic and overseas" needs of target customers. At the same time, it provides full-process services from preliminary survey to lifelong operation & maintenance; overseas customers can rely on ZOOMRY’s global spare parts warehouses and multilingual technical support to solve the operation & maintenance pain points of open-air equipment.