🛠 NEMJO Rice Destoning Machine

📌 Problem Statement

In many rice-producing regions of Africa, post-harvest processing is a critical bottleneck. One major quality issue is the presence of stones and grit in locally milled rice. This contamination:

• Reduces the market value and consumer appeal of local rice.
• Discourages consumers, especially urban dwellers, who prefer imported rice for its cleanliness.
• Prevents smallholder farmers from accessing premium markets, including supermarkets and bulk buyers.
• Increases dependence on large processing firms, who charge high fees or require exclusive supply contracts for destoning services.

While industrial destoners exist, they are:

• Expensive to acquire and maintain.
• Complex to operate without skilled technicians.
• Often inaccessible in rural or off-grid areas.

✅ NEMJO’s Practical Innovation

Objective: To design a low-cost, easy-to-use rice destoning machine that small-scale farmers, cooperatives, and micro rice processors can afford and operate independently — without sacrificing effectiveness.

🔍 Design Philosophy:

• Affordability: Cost optimized to be accessible to rural farmers without external funding.
• Simplicity: Operable with minimal training, using locally available components.
• Effectiveness: Capable of separating stones and heavy impurities with high accuracy.
• Portability: Compact and lightweight design suitable for off-grid or mobile processing units.

🧪 Research and Development Approach

• Conducted field surveys in local rice-producing communities to understand farmer pain points, manual techniques used, and budget constraints.
• Studied principles of density separation, especially gravity-based and vibratory systems used in industrial destoners.
• Identified opportunities to replicate core separation mechanisms using simple materials and locally fabricable parts.
• Prototyped various vibration tray and fan-driven airflow configurations to achieve effective separation of rice and heavier debris.

🔧 Key Features & Uniqueness

• 🌀 Gravity-Vibration Separation Mechanism: Uses a vibrating inclined tray to move rice forward while separating heavier particles like stones. Operable with basic motors or manual cranks.
• 🍃 Airflow Enhancement (Optional): Uses low-powered fan to remove husk, dust, and lighter particles.
• 💸 Ultra-Low Manufacturing Cost: Constructed from mild steel, plywood, and local components; repairable in rural workshops.
• 🔧 DIY Maintenance and Assembly: Modular design for easy local assembly and part replacement. Includes clear instructions for cooperatives.
• 📏 Scalable Throughput: Available in 10–50kg/hr models for various user scales.

🌾 Impact on Local Communities

• Improves rice quality at source, raising market value.
• Reduces contamination and post-harvest losses.
• Empowers farmers by reducing reliance on large millers.
• Encourages youth involvement in agro-processing innovation.
• Supports food security and rural economic development.