Intelligent Fully‑Automatic Mixed‑Flow Grain Drying Equipment with Low‑Temperature Tempering and Low Breakage

   The Mixed-Flow Grain Dryer (5HSN series) is a tower-type continuous drying system developed by Zhengzhou Wangu Machinery for premium grain drying. It adopts low-temperature, thin-layer mixed-flow technology integrating concurrent, countercurrent and cross-flow heat exchange modes, using clean hot air as the heating medium. It is engineered for large-scale gentle drying of paddy rice, wheat, soybeans, rapeseed and sorghum.
   The core structure comprises 4 drying sections, 4 tempering sections and 2 cooling sections, with staggered angular air ducts arranged layer by layer in the drying sections. Grain flowing downward is heated gently by alternating high/low-temperature air, with grain temperature strictly kept within 55C - no scorching, no discoloration. This makes it especially suitable for high-value grain processing (export-oriented crops, premium food production) where color, texture and integrity are critical.
   The series offers five standard models - 5HSN-100, 200, 300, 500 and 800 - with daily capacity of 100-800 tons, customizable up to 1000 t/d, covering capacity needs from large farms and grain depots to industrial processing plants. Moisture reduction ranges 3-15% (up to 16% in a single pass), reducing 25% high-moisture grain to 14% safe storage moisture in one pass, with 24-hour continuous operation.
   The dryer supports biomass, coal, gas and electricity heat sources; the tower body and hot-air pipes are wrapped with 50mm insulation cotton, with unit heat consumption of 5000-7000 kJ/kg. The outdoor windproof and rainproof design eliminates the need for a building. Automatic feeding/discharging systems (linked to level sensors) and a frequency-conversion six-impeller discharge device enable intelligent control with low labor intensity.

Drying Technology

   The equipment employs a mixed-flow drying process that integrates concurrent, countercurrent and cross-flow heat exchange within one tower: angular air ducts in the drying sections are arranged in a staggered pattern, so hot air passing through the grain bed exchanges heat with the downward grain flow in concurrent, counter and cross directions simultaneously. Air paths interlace layer by layer, ensuring full contact between hot air and every kernel - no drying dead zones, no local overheating.
The process advances in three stages. Stage 1 - Drying sections: clean hot air is evenly distributed through angular ducts, penetrating the thin grain flow at a low 45-80C for gentle heating and moisture removal. Stage 2 - Tempering sections: dried grain pauses here while internal moisture and temperature naturally equalize and internal stress is fully released, effectively reducing rice fissuring and cracking. Stage 3 - Cooling sections: cold air penetrates the grain layer in counter-flow, bringing grain temperature to within ambient +8C - cool discharge avoids moisture re-absorption and ensures storage stability.
   With 4 rounds of alternating drying and tempering followed by cooling discharge, grain experiences no thermal shock throughout. Compared with unidirectional cross-flow or concurrent dryers, the mixed-flow process delivers lower grain temperature and more uniform heating: outlet moisture uniformity is within 1.5%, breakage increase below 0.5% and crackle increase below 3%, yielding significantly higher head rice rates and commodity value than ordinary drying processes.

 Structural Composition

The mixed-flow grain dryer consists of the following core components:
- Tower Body: stainless steel/carbon steel structure with high-strength stamped steel core components; tower body and hot-air pipes wrapped with 50mm insulation cotton to minimize heat loss; outdoor windproof and rainproof design, no building required.
- Drying Sections (4): built-in staggered angular air ducts distribute hot air evenly layer by layer through the grain bed for mixed-flow heat exchange and dehydration.
- Tempering Sections (4): dried grain pauses here for moisture/temperature equalization and stress release, reducing fissuring and cracking.
- Cooling Sections (2): cold air penetrates the grain layer in counter-flow; outlet grain temperature is within ambient +8C, ready for direct storage.
- Staggered Angular Air Ducts: the core air distribution structure in drying sections, arranged layer-staggered, made of high-strength stamped steel with high strength, high precision and no grain leakage.
- Auto Feeding/Discharging System: feeding and discharging are linked to level sensors, requiring no manual grain loading supervision.
- Frequency-conversion Discharge Device: six-impeller variable-speed discharge flexibly adjusts grain residence time by variety and moisture content.
- Heat Source System: standard biomass-fired hot air furnace, with optional coal, gas and electricity heat sources configured to local energy prices.
- Control System: intelligent control with precise drying parameter regulation, automatic feed/discharge linkage, low failure rate and easy operation.

Core Advantages

Main Features

1. Triple-flow Mixed Process: staggered angular ducts enable concurrent, counter and cross-flow heat exchange simultaneously, so every kernel fully contacts the hot air - no dead zones, no local overheating, uniform heating across the whole grain column.

2. Low-temperature Thin-layer Gentle Drying: hot air at 45-80C keeps maximum grain temperature below 55C; grain heats and cools slowly through alternating airflows - no scorching, no discoloration, no germ damage, fully preserving color and texture for export rice and premium food ingredients.

3. Multi-section Structure (4D+4T+2C): four drying sections alternate with four tempering sections - after each drying round, grain tempers to release internal stress - followed by two cooling sections for cool discharge. This structure markedly reduces rice fissuring and raises head rice yield, the key safeguard for high-value grain quality.

4. Low Breakage & Uniform Moisture: breakage increase below 0.5%, crackle increase below 3%, and outlet moisture uniformity within 1.5%. Dried paddy yields higher head rice rates and better commodity grades, directly boosting sales price and export competitiveness.

5. Intelligent Automatic Operation: the auto feeding/discharging system is linked to level sensors, and the six-impeller frequency-conversion discharge adjusts throughput flexibly by moisture content; the intelligent control system regulates drying parameters precisely, minimizing human error and ensuring batch consistency.

6. Wide Moisture Reduction in One Pass: moisture reduction of 3-15% (up to 16% in a single pass) brings 25% high-moisture freshly harvested grain down to 14% safe moisture in one pass - no second drying needed for high-moisture or rain-harvested grain, saving time and energy.

7. Outdoor All-climate Durable Structure: core components are made of high-strength stamped steel with few moving parts and low failure rate; 50mm insulation cotton covers the tower body and hot-air pipes; the windproof and rainproof design supports open-air installation. Reliable long-term operation from tropical to temperate regions, with annual maintenance costing only 1-2% of equipment cost.

 Application Fields

   This mixed-flow grain dryer is optimized for paddy rice drying while also handling wheat, soybeans, rapeseed and sorghum. It is widely used by large farms, agricultural cooperatives, grain depots and storage centers, rice mills, flour mills, seed companies and export-oriented grain processors:
- Paddy rice drying (core application): low-temperature mixed flow with multi-stage tempering markedly reduces fissuring, protecting kernel integrity and eating quality for export rice and premium food production;
- Wheat/soybean drying: thin-layer mixed-flow uniform heating preserves gluten and protein quality;
- Rapeseed drying: low temperature protects oil yield while quickly bringing high-moisture rapeseed to safe storage moisture;
- Sorghum and coarse grains: flexibly adjustable parameters suit different variety characteristics.
   The dryer uses clean hot air as the heating medium with indirect heat exchange - no flue gas contamination - so dried products meet food hygiene standards. Outlet grain temperature approaches ambient, allowing direct long-term storage. Five models from 5HSN-100 to 800 cover 100-800 t/d capacity needs, with larger capacities available through parallel towers or customization, serving scenarios from large-scale farms to central grain depots.

Packaging & Warranty

   Each mixed-flow grain dryer is shipped in standard packing with core components well protected, meeting sea and land transport requirements; custom packing is also available. All equipment is produced under the ISO quality management system and tested before delivery. The complete machine enjoys a 12-month warranty, with online technical support, engineer-guided installation and spare parts supply. Minimum order: 1 set; delivery: 60-80 days; payment: T/T or L/C. Please tell us your required daily capacity, grain type and heat source preference, and we will recommend a suitable configuration among the five standard models 5HSN-100 to 5HSN-800 (larger capacities via parallel towers or customization) with a competitive quote.