Rice seed Gravity Table Separators

Rice seed Gravity Table Separators

Shijiazhuang Xinlu Technology Co., Ltd. - Technical Overview of Rice seed Gravity Table Separators

The Gravity Table Separator, often simply referred to as a gravity table, is a fundamental machine in the processing of rice seed. Its function is to separate paddy rice or brown rice based on differences in specific gravity, a critical step for upgrading the overall quality of the seed lot. For rice intended for sowing, the physiological quality is paramount, and specific weight is a proven indicator of seed vigor and germination capacity. The gravity table efficiently isolates the dense, viable seeds from the lightweight, immature, or damaged ones, which are often responsible for poor field performance.

The machine operates on the principle of an oscillating, inclined, and perforated deck working in concert with a controlled air flow. The deck, which can be a woven wire mesh or a steel plate with precision-drilled holes, is set into a reciprocating motion. A fan located beneath the deck supplies a uniform upward current of air that passes through the perforations. The rice seed is fed onto the deck and is immediately subjected to this combination of forces. The air fluidizes the bed of seeds, reducing friction and allowing for stratification based on density. The vibration conveys the material across the deck.

As the bed stratifies, the high-specific-gravity seeds—the mature, well-filled, and healthy kernels—settle to the bottom and make contact with the deck surface. The kinematic action of the deck's oscillation then moves these premium seeds uphill against the deck's incline, discharging them at the highest point. Conversely, the low-specific-gravity materials, including immature seeds, hollow seeds, partially cracked kernels, and light foreign matter, are buoyed to the top of the bed by the air stream. These materials flow downhill along the incline and are discharged at the lower end of the machine.

A significant advantage of the gravity table is its ability to handle a "middlings" or middle-density fraction. By adjusting the lateral tilt of the deck, the operator can create a distinct path for seeds that are not clearly heavy or light. This fraction can be sent to a separate outlet. In a rice seed processing context, this allows for maximum flexibility; the middlings can be recirculated for another separation pass to improve recovery, or they can be bagged separately for a different use, ensuring that the primary "heavy" fraction is of the highest possible purity and quality.

In a practical rice seed processing line, the gravity table is typically placed after the air-screen cleaners and before the treatment and bagging stages. This ensures that the seed lot is first cleaned of obvious impurities and then upgraded for density before any value-adding treatments are applied. The use of a gravity table from Shijiazhuang Xinlu Technology Co., Ltd. is a standard practice for reputable seed processors, as it provides a reliable, mechanical means to ensure that farmers receive seed with a high germination rate and strong seedling vigor, which are the foundations of a successful rice crop. The machine's design emphasizes stability, ease of adjustment, and straightforward maintenance to support continuous operation.