Rotary Rice Grader Grain Processing Machinery

Product Overview

Unlike static screening systems, the rotary design creates continuous motion that prevents clogging and ensures thorough separation, achieving a sorting accuracy of 99.5% for most rice varieties. Its compact footprint and quiet operation make it suitable for integration into existing processing lines without major modifications, enhancing overall production efficiency.

Product Features

Multi-Layer Sieve Cylinders

Equipped with 2 or 3 concentric rotating sieve cylinders (depending on model), each with precision-drilled apertures of 1.5-3.0mm (interchangeable based on grain size), the grader achieves multiple separation stages in a single pass. The outer cylinder removes large impurities, the middle cylinder separates whole grains, and the inner cylinder collects small broken pieces and fines.

Self-Cleaning Mechanism

Integrated bouncing balls mounted inside each sieve cylinder continuously strike the screen surfaces during rotation, preventing grain buildup and maintaining consistent throughput. This self-cleaning feature reduces manual intervention requirements by 80% compared to fixed-screen graders.

Variable Speed Control

A 7.5 kW variable frequency drive allows operators to adjust rotation speed between 30-60 rpm according to rice type and quality requirements. Finer adjustments (±5 rpm) can be made to optimize separation efficiency for different rice varieties, from short-grain to long-grain types.

Dust-Controlled Operation

The fully enclosed rotating drum design, combined with integrated dust collection ports, captures airborne particles generated during grading. When connected to a central dust extraction system, it reduces workplace dust levels by 90%, improving operator health and meeting environmental regulations.

Product Applications

Rice Milling Lines

Installed after polishing and before packaging, the grader ensures only uniformly sized whole grains proceed to premium markets, while broken grains are diverted to secondary processing (flour production, food ingredients) for maximum value recovery.

Seed Rice Processing

In seed production facilities, the grader's precise separation ensures consistent seed size, which promotes uniform germination and crop establishment. This is particularly critical for hybrid rice varieties where seed uniformity directly impacts yield potential.

Export Quality Control

For rice destined for international markets with strict quality standards, the grader removes off-spec grains and impurities, ensuring compliance with import regulations and reducing rejection risks at customs inspection.

FAQ

How often should the sieve cylinders be replaced?

Under normal operating conditions (8-hour daily use), sieve cylinders typically last 6-8 months for standard rice varieties. For abrasive varieties or higher throughput, replacement may be needed every 4-5 months. The quick-release design allows cylinder replacement in less than 1 hour without specialized tools.

Can the grader handle parboiled rice?

Yes, with the optional parboiled rice kit (including specialized sieve materials and adjusted rotation speeds), the grader effectively processes parboiled rice. The kit modifies the sieve aperture shape to oval (2.0×3.5mm) and reduces optimal rotation speed to 35-40 rpm to accommodate the harder texture of parboiled grains.

How is the separation efficiency maintained?

The grader features a built-in monitoring system that continuously checks throughput and separation quality. If efficiency drops below 98% (indicated by increased broken grains in the whole grain outlet), the system alerts operators to check for sieve damage, adjust rotation speed, or clean the sieve surfaces—typically restoring efficiency within minutes of intervention.