The trough-shaped idler is the core component of the carrying section in belt conveyors. By combining multiple sets of idlers, it forms a "V-shaped groove structure" that supports the conveyor belt and bulk materials (such as coal, ore, sand, and gravel), guiding the materials to concentrate in the center of the belt for efficient transportation. At the same time, it helps minimize belt sagging and reduces running resistance. Its primary function is to achieve "efficient load-bearing and material guidance," making it widely used in various bulk-material handling applications. The core value lies in enhancing the belt's load-carrying capacity, minimizing material spillage, and ensuring stable operation of the entire conveying system—making it an essential "standard component" for long-distance, high-capacity conveyor lines.

1. Structural Design: The Core Logic of Groove-Shaped承载

The structural design of the trough-shaped idler revolves around "enhancing load-bearing capacity and optimizing material guidance," with the core components and design features outlined below:

Roller unit: Composed of 1 set of center rollers plus 2 sets of side rollers (some special models also include transition rollers). The center rollers are arranged horizontally, while the side rollers are tilted outward on both sides, collectively forming a trough-shaped structure. The roller bodies can be made from materials such as carbon steel, stainless steel, ceramic, or high-performance polymers, with surfaces treated for enhanced wear resistance (e.g., chrome plating or powder coating). Roller diameters range from φ89 to φ219 mm, and lengths are customized to match the width of the conveyor belt.

Support structure: The core component that connects the roller units to the conveyor frame, fabricated by welding or stamping steel plates, with a surface treated for corrosion protection (galvanized or powder-coated). The support must be strong enough to handle the load; in heavy-duty applications, thicker steel plates (at least 6mm thick) are used to ensure there is no risk of deformation or fracture.

Bearings and Seals: The idler rollers are equipped with either deep-groove ball bearings or self-aligning roller bearings, paired with long-lasting grease (high-temperature/low-temperature resistant types available as options) to minimize rotational resistance. The sealing system features a dual-layer design—combining "labyrinth" and "contact" seals—to achieve an IP65-rated protection level or higher, effectively blocking out dust and moisture while significantly extending the bearing's service life.

Groove angle design: The inclination angle of the side idlers (i.e., the groove angle) is a key parameter. Common groove angles are 15°, 30°, and 45°. The larger the groove angle, the greater the cross-sectional area of the conveyor belt capable of holding material (under the same belt width, a 45° groove angle increases material capacity by more than 30% compared to a 30° groove angle). However, this must be matched with the belt's ability to form a stable trough shape, preventing excessive stretching at the belt edges.

II. Core Advantages: The Key Value of Bulk Material Handling

Enhancing load-bearing capacity to accommodate high-capacity conveyance: The trough-shaped structure enables the conveyor belt to form a "U-shaped" cross-section, increasing material-carrying capacity by 50%–80% compared to flat idlers (under the same belt width). This design can meet the demands of high-volume transportation ranging from hundreds to thousands of tons per hour—such as in mine-scale conveyor systems capable of handling up to 10,000 tons per hour.

Reduce material spillage and lower loss costs: The trough-shaped structure keeps materials securely centered on the conveyor belt, preventing them from spilling due to vibration or tilting during transport. This reduces material loss rates to below 1%, while also minimizing the workload associated with on-site cleanup.

Protect the conveyor belt and extend its service life: Multiple sets of idlers evenly support the conveyor belt, reducing belt sagging (sagging degree ≤1%) and preventing localized stress concentration. Additionally, cushion-type trough-shaped idlers absorb material impacts, safeguarding the belt from being torn by sharp objects, thereby extending its lifespan by 20% to 30%.

Reduce running resistance to achieve energy savings and consumption reduction: The idlers feature precision bearings and a low-friction sealing design, resulting in a rotational resistance coefficient of ≤0.02—15%–20% lower than that of conventional flat-type idlers, significantly cutting down on drive power consumption and enabling substantial long-term electricity cost savings.

Highly adaptable and compatible with multiple operating conditions: Depending on material characteristics (temperature, corrosiveness, hardness), you can choose rollers made from different materials—for example, metal rollers for high-temperature applications, or stainless steel/high-polymer rollers for corrosive environments. Additionally, the trough angle and length are customizable, making these rollers suitable for conveyor belts of all standard sizes ranging from 500 to 2400 mm.

Easy to install and maintain, offering excellent value for money: The structure features a high degree of standardization, eliminating the need for complex adjustments during installation. Daily maintenance simply involves regularly checking the bearing rotation and sealing conditions, resulting in low maintenance costs. Under normal operating conditions, a single set of idlers can last anywhere from 2 to 5 years.

3. Applicable Industries and Typical Application Scenarios

The trough-shaped idler is a "fundamental component" for bulk material transportation, widely used in the following industries:

Mining Industry: Mining and conveying systems for ores such as coal, iron ore, copper ore, etc. (e.g., underground raw coal transportation, surface concentrate powder conveyance), designed to handle heavy loads and meet high-flow demands;

Building Materials Industry: Cement, sand and gravel, ceramic raw materials, and gypsum powder conveyor systems—deep-groove idlers can significantly enhance the efficiency of transporting cement clinker and aggregates.

Power Industry: Coal conveyor systems in thermal power plants and biomass power generation feed lines; buffer trough-type idlers are ideally suited for handling the impact of coal discharge scenarios.

Port terminals: Bulk cargo (coal, ore, grain) handling and conveying systems with deep-groove idlers to meet the port's demand for "high throughput" transportation.

Metallurgical Industry: Steel plant sinter ore and blast furnace slag conveyor lines feature high-temperature-resistant metal trough-type idlers, perfectly suited for handling materials under extreme heat conditions (up to 120°C).

Chemical Industry: Conveyor systems for chemical powders and granules (such as fertilizers and soda ash); stainless steel/high-polymer trough-type idlers resistant to corrosive materials.

Grain processing industry: Grain conveyor systems for wheat, corn, soybeans, and other cereals—using standard trough-type idlers can minimize grain spillage and ensure hygienic transportation.

Infrastructure Industry: Construction project sand and gravel, concrete aggregate conveying lines, compatible with mobile conveyors, meeting the flexible material-handling needs of construction sites.

  IV. Selection Guide: Precisely Match Conveyor System Requirements

Selecting based on conveyor belt parameters:

Conveyor belt width: The roller length should be 100–200 mm greater than the belt width (e.g., if the belt width is 1200 mm, select a roller length of 1400 mm) to ensure the conveyor belt fully covers the rollers.

Belt troughability: Standard canvas conveyor belts are suitable for groove angles of 30° or less, while high-strength nylon conveyor belts can accommodate deeper groove angles up to 45°, preventing excessive stretching at the belt edges.

For conveying speeds: Use standard bearings for low speeds (≤2 m/s), and high-precision self-aligning roller bearings for high speeds (＞2 m/s) to minimize rotational heat generation.

Selecting based on material properties:

Material hardness/impact: For high-hardness materials (such as ore), choose metal idlers; for materials subjected to high-impact drops, opt for buffer-slot type idlers.

Material temperature: For ambient temperatures (-20℃ to 80℃), choose standard materials; for high temperatures (80℃ to 120℃), select metal idlers; and for low temperatures (< -20℃), opt for cold-resistant polymer idlers.

Material Corrosivity: For corrosive materials (such as acidic or alkaline solutions, salt spray environments), select stainless steel or polymer rollers.

Select the model based on the load capacity:

Light load (≤5 kN): Select φ89–φ108 mm rollers, with bracket steel plate thickness of 4–5 mm;

Medium load (5-15 kN): Select rollers with diameters ranging from φ133 to φ168 mm, and use support bracket steel plates with a thickness of 5-6 mm.

Overload (>15 kN): Select rollers with diameters ranging from φ168 to φ219 mm, use support bracket steel plates with a thickness of 6–8 mm, and choose self-aligning roller bearings.

Select based on the installation location:

Regular carrying section: Select standard/deep-groove idlers;

Near the roller/curve: Choose transition trough-type idlers;

Below the discharge port: Select buffer-type idlers;

Slope-prone sections: Choose groove-type idlers with self-aligning features.

5. Key Points for Installation and Maintenance

Installation Guidelines:

Spacing settings: For standard load sections, the spacing is 1–1.5 m; for heavy-load sections, it’s 0.8–1 m; and near the discharge opening, the buffer idlers are spaced 0.5–0.8 m apart.

Level Calibration: The roller supports must be installed horizontally, with the center roller axis parallel to the conveyor belt's centerline and the side roller groove angle deviation kept within ≤1°—this prevents uneven loading that could cause the conveyor belt to drift off course.

Ensure secure fastening: Tighten the mounting bolts connecting the bracket to the rack (torque should be set according to bolt specifications; for example, use 30–40 N·m for an M12 bolt) to prevent loosening during operation.

Daily Maintenance:

Weekly inspection: Check the flexibility of roller rotation (no sticking or unusual noises), clean off any material adhering to the surface, and verify whether the side roller groove angles are deformed.

Monthly inspection: Check bearing temperature (≤60°C during operation), inspect seals for damage, and promptly replace any seals if oil leakage or dust ingress is detected.

Quarterly maintenance: Replenish lubricant grease in the bearings (use lithium-based grease, filling 1/3 to 1/2 of the bearing's internal space), and remove rust from corroded components before applying a fresh coat of anti-corrosion paint.

Fault replacement: When rollers become jammed, the body wears down by ≥3mm, or the support structure deforms, they must be replaced promptly to prevent damage to the conveyor belt.

Storage requirements:

Store in a dry, well-ventilated warehouse to prevent rusting of the roller body and its bracket.

Single-row rollers should be stored upright, with stacking no higher than 5 layers to prevent deformation of the support structure due to pressure.

Long-term storage (＞6 months) requires periodic rotation of the rollers to prevent bearing grease from solidifying.