How to Select the Right Belt Conveyor for Peanut Processing

Food Machinery and Equipment | Design and Optimization of Conveying Systems in Peanut Deep Processing Lines

1. Overview of Peanut Deep Processing Process Flow

Peanut deep processing refers to the process of converting peanut raw materials into high-value-added products through multiple steps, mainly including raw material handling, grading and screening, roasting and baking, dehulling and red skin removal, grinding and paste making, frying and seasoning, packaging and sterilization, etc. In these processes, belt conveyors, as key equipment for material conveying, play an indispensable role.

Typical Process Flow of Peanut Deep Processing

1Raw Material Reception and Cleaning

2Grading and Screening

3Roasting and Baking

4Dehulling and Red Skin Removal

5Grinding and Paste Making

6Frying and Seasoning

7Packaging and Sterilization

Note: Belt conveyors run through all the above processes, enabling continuous and efficient material conveying.

2. Analysis of Belt Conveyor Applications in Peanut Processing

2.1 Application of Rubber Belt Conveyors in Peanut Processing

Rubber belt conveyors are widely used in continuous conveying machinery in food factories, commonly for horizontal or inclined transportation of bulk, granular, and whole materials. In peanut processing, many pieces of processing equipment, such as sorting lines, filling lines, continuous dryers, and continuous freezers, use belt conveyors.

Peanut Processing Application: Rubber belts are mainly used in peanut deep processing for loading, unloading, and conveying bulk peanut raw materials and packaging items. They can also be used as conveying-type inspection tables and conveying equipment for preprocessing steps. For example, in the raw material reception and preprocessing stages, rubber belts can transport raw materials from warehouses to cleaning equipment; in the packaging stage, they can transport finished peanuts to packaging machines for automatic packaging.

Technical Requirements: Rubber belts used in peanut processing must comply with food safety standards. The surface cover rubber should be made of food-grade materials. The working surface cover thickness is typically 3–6 mm, and the non-working surface cover thickness is 1–3 mm to ensure sufficient wear resistance and hygiene.

Rubber Belt Marking Example: Width (mm) × Number of plies × (Working surface rubber thickness + Non-working surface rubber thickness) (mm) × Length (m). Example: 800 × 8 × (6+3) × 100, indicating a belt width of 800mm, 8 plies, working surface rubber thickness of 6mm, non-working surface rubber thickness of 3mm, and length of 100m.

2.2 Application of Plastic Belts in Peanut Processing

Plastic belts are made from polyvinyl chloride and are primarily used as traction and carrying components of belt conveyors. They are divided into solid-woven core and multi-ply core types. Solid-woven core plastic belts have simple manufacturing processes and low costs, with good performance except for relatively poor flexibility. Multi-ply core plastic belts have a strength similar to that of ordinary rubber belts and consist of a carcass and cover layers.

Peanut Processing Application: Plastic belts offer advantages such as abrasion resistance, acid and alkali resistance, oil resistance, and corrosion resistance, making them particularly suitable for conveying peanut products with high oil content. In production lines for fried peanuts, peanut butter, and other oily products, plastic belts perform significantly better than rubber belts and do not experience reduced service life due to oil erosion.

Application Example: In peanut-frying production lines, plastic belts transport pretreated peanuts to the frying vat and then transport the fried products to the seasoning and cooling processes. The oil resistance of plastic belts ensures long-term stable operation and reduces maintenance frequency.

2.3 Application of Slat Belts (Plate Belts) in Peanut Processing

Slat belts, also known as chain slat conveyors, are formed by connecting many articulated chains. This type of slat belt needs to be installed on a specialized chain slat conveying device. The movement of the conveyed material is driven by the traction of the slat articulated chain, while the support force for the slat belt and the conveyed items is provided by guide plates fixed underneath the slats.

Peanut Processing Application: Slat belts are mainly used in production lines for canned peanuts, peanut beverages, etc., and for conveying various peanut product packaging boxes. In peanut canning production lines, slat belts can stably convey can containers, ensuring precise filling and sealing positions.

Special Design: Certain peanut-processing steps (such as inclined conveying of peanut kernels) require large conveying angles. When friction cannot keep the material stationary relative to the belt, baffles (scrapers) of a certain height can be added to the slat belt to prevent material slippage.

2.4 Application of Canvas Belts in Peanut Processing

Canvas is a relatively thick cotton or linen fabric. Canvas conveyor belts are called canvas belts. Their characteristics include high tensile strength, good flexibility, and the ability to withstand repeated folding without fatigue. Canvas is usually joined using cotton thread and synthetic fibers, and in rare cases, with leather strips.

Peanut Processing Application: In production lines for peanut biscuits, peanut crisps, and other baked products, canvas belts are mainly used for conveying dough sheets and biscuit blanks before forming, such as dough sheet lamination, shortening rolling, and biscuit forming. The flexibility and breathability of canvas belts help maintain the dough’s proper state.

Advantages: The length of canvas belts can be adjusted to meet actual production needs, making them very convenient for peanut product production. For example, on peanut biscuit production lines, the conveyor belt length and speed can be quickly adjusted according to the size and output requirements of different products.

2.5 Application of Wire Mesh Belts in Peanut Processing

Wire mesh belts feature high strength and high-temperature resistance. Because they have mesh openings, and the mesh size can be selected as needed, the length of the mesh belt can also be chosen arbitrarily. Wire mesh belts are often used in applications that require simultaneous conveying and solid-liquid separation.

Peanut Processing Application: In peanut deep processing, wire mesh belts are widely used in the following links:

• Cleaning Link: In peanut raw material cleaning equipment, wire-mesh belts can convey peanuts while allowing mud and water to pass through the mesh openings.
• Frying Link: In continuous fryers, wire mesh belts convey peanuts through the oil bath, allowing excess oil to drain back through the mesh.
• Roasting Link: In peanut roasting equipment, wire-mesh belts are heat-resistant and breathable, ensuring even heating of the peanuts.
• Cooling Link: Fried or roasted peanuts can be conveyed and cooled on wire-mesh belts, thereby accelerating the cooling process.

2.6 Application of Steel Belts in Peanut Processing

Steel belts are primarily made of stainless steel. When conveying high-temperature materials, rubber belts can release harmful substances, while steel belts do not. Therefore, steel belts are suitable for high-temperature conveying applications and are particularly well-suited to the food industry.

Peanut Processing Application: Steel belts are mainly used in high-temperature working environments. The most typical application in peanut processing is the conveying device in continuous baking ovens. For example, in peanut roasting and baking production lines, steel belts can withstand temperatures above 200°C, ensuring even peanut roasting.

Precautions: Due to their high rigidity, larger-diameter drums are required to prevent steel belt breakage; steel belts are sensitive to impact loads, requiring accurate installation and regular monitoring during operation; steel belts are expensive and are generally used only for critical, high-temperature processes.

Comparison of Various Conveyor Belt Applications in Peanut Deep Processing

3. Key Technologies for Peanut Processing Conveying Systems

3.1 Drive Unit Design and Selection

The drive unit of a belt conveyor generally includes an electric motor, reducer, drive drum (sprocket), etc. In peanut processing production lines, especially on inclined conveyors, braking devices or backstops are usually installed to prevent material backflow.

Special Requirements for Peanut Processing:

• Anti-slip Design: Peanut raw materials and products have a certain oil content, which can easily cause belt slippage. The drive drum surface should be patterned or coated to increase the coefficient of friction.
• Speed Adjustability: Different peanut products have different conveying speed requirements (e.g., for roasting time control). The drive unit should be equipped with variable frequency speed control.
• Hygienic Design: The drive unit should be easy to clean, avoiding accumulation of oil and material residues, and comply with food hygiene standards.

3.2 Optimization Design of Frame and Idler Rollers

The frame is mainly welded from channel steel, angle iron, and steel plates. It serves as the main load-bearing structure in the belt conveyor. Idler rollers primarily support the conveyor belt and the conveyed material, ensuring smooth operation.

Key Points for Peanut Processing Application:

• Dust-proof Design: Peanut processing generates dust. Idler rollers and frames should be designed for easy cleaning to reduce dust accumulation.
• Corrosion-resistant Materials: In humid or corrosive environments, such as cleaning and frying, frames and idler rollers should be made of stainless steel or have corrosion-resistant coatings.
• Special Idler Selection: For bulk materials like peanut kernels, trough idlers are mostly used to increase conveying capacity; for packaged items like peanut oil bottles, flat idlers are sufficient.

3.3 Optimal Configuration of Tensioning Devices

Most conveyor belts have a certain elongation rate. Under prolonged, significant tension, their length can increase slightly. This increase directly reduces the pressure between the conveyor belt and the drive drum, lowering friction and potentially causing the belt to slip.

Tensioning Requirements for Peanut Production Lines:

• Automatic Tensioning: In continuously running peanut processing production lines, counterweights or automatic tensioning devices are recommended to reduce the frequency of manual adjustments.
• Temperature Compensation: Peanut roasting and frying processes involve large temperature changes. The tensioning device should compensate for the thermal expansion and contraction of the conveyor belt.
• Hygiene Considerations: Tensioning devices should be designed in positions that are easy to clean, avoiding becoming hygiene dead ends.

4. Design Suggestions for Peanut Deep Processing Conveying Systems

Based on the characteristics of peanut deep processing and the application experience of belt conveyors, the following design suggestions are proposed:

1. Systematic Design: The peanut deep processing conveying system should be designed from the perspective of the entire production line to ensure coordination and efficiency between processes.

2. Hygiene Priority: All conveying equipment should comply with food hygiene standards, adopt easy-to-clean designs, and avoid cross-contamination.

3. Flexible Configuration: Considering the diversity of peanut products, the conveying system should have a certain degree of flexibility to adapt to different products and process requirements.

4. Energy-saving Considerations: Reasonably select motor power and adopt technologies such as variable frequency speed control to reduce energy consumption.

5. Safety Protection: The conveying system should be equipped with necessary safety protection devices, such as emergency stop switches, protective covers, etc.

6. Easy Maintenance: Key components should be easy to inspect and replace, reducing downtime.

With the continuous development of peanut deep processing technology, belt conveyors are also constantly innovating and improving. In the future, more intelligent, modular, and hygienically designed conveying equipment will be more widely used in the peanut processing industry, providing strong support for improving peanut product quality, reducing production costs, and increasing production efficiency.