Horizontal Emery Roller Rice Whitener Manufacturer

Precision Abrasion: The Technology of the Horizontal Emery Roller Rice Whitener

Introduction
After paddy rice has been husked and separated, the result is brown rice—a whole kernel with the nutritious bran layer still intact. For many markets, the next step is to remove this bran layer to create white rice, which has a longer shelf life, a different texture, and a milder flavor. The Horizontal Emery Roller Rice Whitener is a core machine designed to perform this task through controlled abrasion. This article from Shijiazhuang Xinlu Technology Co., Ltd. explores the engineering, function, and critical control parameters of this essential milling machine.

From Brown Rice to White Rice
The bran layer is composed of the aleurone and pericarp, which contain oils, vitamins, minerals, and fiber. The whitening (or polishing) process must remove this layer uniformly without generating excessive heat that can crack the kernels or cooking the starch within, which would gelatinize it and make the rice sticky.

Design and Mechanics of the Horizontal Emery Whitener
The machine's design is focused on creating a consistent, controllable abrasive action.

1. The Emery Roller: The heart of the machine is a horizontal rotating shaft onto which are fixed one or more cylinders made of a composite material embedded with sharp, hard silicon carbide or alumina grit (emery). This creates an extremely abrasive surface. The roller's speed is controllable, directly influencing the intensity of the abrasion.

2. The Screen Cage: Surrounding the emery roller is a stationary cylindrical screen cage, typically made of perforated sheet metal (with slotted or round holes) or a woven wire mesh. The gap between the rotating roller and the stationary screen is where the whitening action occurs.

3. Feed and Discharge Mechanism: Brown rice is fed axially into one end of the machine.

• Feed Control: A feed worm or feeder gate regulates the inflow, creating a "plug" of rice that must be pushed through the machine. This pressure is crucial for controlling the residence time and degree of whitening.

• Pressure Adjustment: A weighted lever or pneumatic system on the outlet door applies counter-pressure on the rice column inside the machine. Increasing this pressure makes it harder for the rice to exit, forcing it to spend more time being abraded against the screen, resulting in a higher degree of whiteness (and more breakage if overdone).

4. The Whitening Process: As the emery roller rotates at high speed, it imparts a spiraling motion to the rice kernels trapped between itself and the screen. The kernels rub against each other and are scraped against the abrasive roller and the screen. This friction efficiently scours off the bran layer.

5. Bran and Heat Removal: The removed bran is small enough to pass through the perforations in the screen cage and is collected for further processing (e.g., oil extraction, animal feed). The process generates significant heat from friction.

• Air Cooling: A constant flow of air is drawn through the machine, often through the hollow main shaft. This air serves two vital purposes: it carries the bran away from the milling chamber, preventing clogging, and it cools the rice, preventing heat damage and moisture loss that leads to brittleness and breakage.

Technical Considerations and Operational Control

• Degree of Whitening: This is controlled by a balance of three factors: roller speed, feed rate, and back-pressure. Finding the optimal settings for a specific rice variety is key to maximizing whole grain yield.

• Emery Roller Maintenance: Over time, the abrasive grit on the roller wears down. Rolls must be periodically replaced or re-dressed to maintain milling efficiency.

• Screen Selection: Different screen perforation sizes and patterns affect the bran removal rate and the flow of air through the machine.

• Multiple Passes: Often, rice is passed through two or more whiteners in series. The first machine (breaker) does the bulk of the bran removal with a coarser emery roll, while subsequent machines (finishers) use finer abrasives for a polished finish with less mechanical stress.

Advantages and Application
The Horizontal Emery Roller Rice Whitener is known for its:

• High Efficiency: Effective at removing bran and achieving a high degree of whiteness.

• Robustness: Simple, durable construction suitable for high-capacity operations.

• Control: Offers operators precise control over the final product's appearance.

Shijiazhuang Xinlu Technology Co., Ltd. manufactures these whiteners with precision engineering to ensure consistent performance, effective cooling, and durability, making them a cornerstone of modern rice milling lines aimed at producing high-quality, visually appealing white rice.