Description

SKLB Series Swing Cooler – Professional Choice for Pellet Feed Cooling

The SKLB series swing cooler (also known as SKLB swing counterflow cooler) is one of the key devices in the cooling section of feed processing lines. Widely used for uniform cooling of pelleted feed, extruded feed, expanded feed and fragile materials, this series adopts advanced counterflow cooling principles combined with a unique swing-type flap discharge mechanism. It rapidly cools high-temperature, high-moisture pellets from the pellet mill or extruder to a temperature near ambient conditions, ensuring increased pellet hardness while effectively preventing mold growth, thereby providing reliable quality assurance for subsequent packaging, transportation and storage.

1. Equipment Background and Design Positioning

Pellets coming out of the pellet mill or extruder typically have a temperature of 70°C to 90°C and a moisture content of about 15% to 17%. If not cooled in a timely manner, the feed is prone to mold and deterioration, causing significant losses to the enterprise. The SKLB series swing cooler is specifically designed for this process requirement. It skillfully applies the counterflow heat exchange principle, combined with a swing-type flap discharge mechanism and an octagonal, dead-angle-free cooling chamber, ensuring high efficiency while significantly reducing pellet breakage.

2. Working Principle

The SKLB series adopts the counterflow cooling principle, with ambient natural air as the cooling medium. During operation, a fan draws air from the top of the cooler, creating negative pressure inside the chamber. Cold air uniformly enters the machine through gaps in the bottom discharge mechanism. Hot pellets moving downward from above meet upward-flowing cold air inside the chamber; the hot air is exhausted from the top while the pellet temperature gradually decreases. The direction of cold air flow is completely opposite to that of the pellet flow, effectively avoiding surface cracks caused by sudden cooling from direct contact between cold air and hot material.

The equipment features a unique swing-type flap discharge mechanism, controlled by a flexible hydraulic system or pneumatic system. When material accumulates to a set height inside the cooling chamber, the level sensor triggers a signal, and the discharge mechanism automatically completes periodic flap movements, allowing material to move downward uniformly. Discharge flow and speed can be continuously adjusted, ensuring each batch receives the same cooling time.

3. Core Advantages & Technical Features

1. Counterflow heat exchange principle: Cold air moves upward while hot pellets move downward, preventing sudden cooling cracks. After cooling, the pellet surface remains intact, smooth and uniform in color, avoiding brittle cracks from excessive rapid cooling.

2. Swing-type flap discharge mechanism: Driven by a flexible hydraulic or pneumatic system, discharge is smooth and uniform, with adjustable speed, minimizing powdering. Large models are also equipped with an electric rotary leveler to ensure uniform material bed thickness, further improving cooling consistency.

3. Excellent cooling effect: Final material temperature does not exceed ambient temperature +3°C to 5°C, with moisture reduction not less than 3.8%. Finished pellets have increased hardness and are less prone to mold, suitable for long-term storage and long-distance transport.

4. Octagonal low-residue design: The cooling chamber and top cover feature an octagonal cross-section, eliminating cooling dead corners and minimizing material residue, which prevents cross-contamination when changing product types and meets hygiene management requirements of modern feed mills.

5. Wide material adaptability: Suitable for agglomerates, lumps, flakes, powders, hard pellets, expanded feed, extruded feed and various fragile materials, particularly suitable for feed and expanded materials requiring high cooling uniformity.

6. Four-way adjustable leveler and airlock feeder: Levelers distribute material evenly before it enters the cooling chamber. The airlock feeder provides an effective seal to prevent airflow short circuiting, ensuring sustained cooling efficiency.

7. Complete model series coverage: The SKLB series covers effective volumes from 1.5m³ to 10m³, with capacities ranging from 3 t/h to 30 t/h, flexibly adaptable to various feed production lines — from small single-product sections to large integrated feed mills.

8. Easy operation and high automation: Quick-opening large inspection doors are equipped with safety devices for simple daily inspection and cleaning. The mechanical level controller and hydraulic/pneumatic flap system operate automatically, enabling unattended operation and reducing manual workload.

4. Typical Applications

• Aquafeed: Cooling extruded aquatic feed such as floating fish feed, shrimp feed, frog feed and turtle feed; cooled pellets have good water stability and resistance to disintegration.

• Pet food: Soft and even cooling for dry pet food pellets and functional treats, ensuring appropriate pellet hardness.

• Livestock & poultry feed: Cooling conventional pellets such as pig feed and poultry feed, effectively preventing mold during storage.

• Expanded and extruded feed: Forced cooling of expanded materials such as full-fat soybean, especially suitable for processes requiring uniform cooling of high-bulk-density materials.

• Agglomerates, lumps and fragile materials: Including high-moisture agglomerates from special conditioning processes, ensuring smooth transition to dry, hard finished products.

5. Model Parameters and Selection Guide

The SKLB series offers several specifications, with main parameters shown below:

Key selection considerations:

1. Equipment capacity: Base hourly capacity on the actual output of the pellet mill or extruder. It is recommended that cooler capacity slightly exceeds that of upstream equipment, generally taking K=1.1 to 1.3 times the pellet mill output.

2. Material characteristics: Expanded feed requires priority consideration of coolers with larger effective volume and auxiliary components such as rotary levelers to avoid uneven material distribution.

3. Matched fans and cooling time: Typical pellet cooling time ranges from 6 to 15 minutes — larger pellet diameters or higher moisture materials require longer residence time. When selecting, calculate total aspiration based on specific material to ensure adequate system static pressure (recommended ≥200mmH₂O).

4. Drive option selection: Hydraulic systems operate smoothly and quietly, suitable for large-scale and high-quality production lines; pneumatic systems have simpler structure and lower cost, suitable for small to medium feed mills as a basic configuration.

6. Maintenance and Care

1. Daily check the smooth operation of the flap discharge mechanism and the tightness of each proximity switch; regularly clean accumulated material on flap surfaces.

2. Every 200 hours, check seals of hydraulic cylinders or pneumatic cylinders; for hydraulic models, replace hydraulic oil according to schedule and keep oil lines clean and leak-free.

3. Weekly clean the airlock and feeding closure device to prevent dust buildup affecting feeding/discharging.

4. Maintain intact seals on the octagonal cooling chamber and quick-opening inspection door; regularly check reliability of level sensor and leveler to prevent signal failure affecting automatic operation.

5. Regularly remove dust from cooling fans and air ducts to ensure bag filters or cyclones remain unobstructed, preventing airflow reduction that affects cooling uniformity.

Conclusion

The SKLB series swing cooler, with its advanced technologies including counterflow heat exchange principle, flexible swing-type flap discharge, octagonal dead-angle-free cooling chamber and four-way adjustable leveler, has become a mature and reliable equipment representative in the feed processing cooling section. Whether for aquafeed production, pet food extrusion lines, or livestock and poultry pellet lines, choosing the SKLB swing cooler ensures stable, efficient, low-breakage cooling processes. We offer a full range of cooling equipment from SKLB1.5 to SKLB15 and complete plant cooling system solutions. Please contact us for inquiries.

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