Rice is often mixed with impurities such as sand, soil and slag due to various factors in the process of harvesting and drying. Removing stones is the technical focus and difficulty in the process of grain cleaning and impurity removal, and has an important impact on the quality of grain products. How can we remove stones from bulk rice? We had to use a rice destoner. Ang what is the working principle of the stone remover? Let's learn together.

Rice is a finished product made of paddy after cleaning, hulling, milling, and finishing. It is divided into three types: indica rice, japonica rice, and glutinous rice.

In the production process of rice, the removal of impurities and stones from the raw grain is a process that cannot be ignored, which can effectively improve the quality of rice.

An important piece of equipment that needs to be used in this process is the stone removal machine, which can effectively remove stones and other impurities in it, saving time, effort and labor.

At present, there are two kinds of rice destoners produced by grain machinery factories at home and abroad, one is the screening destoner, and the other is the specific gravity destoner.

The Working Principle of Screening Destoner

The working principle of the screening stone removal machine is to remove debris such as stones and straw sticks through two-layer screening. The first layer of sieve of this stone remover is a coarse sieve, and its sieve hole diameter is the same as the diameter of the rice grain, so as to ensure the smooth passage of the rice grain, and at the same time remove the stones and debris larger than the rice grain; the second layer of sieve is a fine sieve, The sieve hole diameter is smaller than the diameter of the rice grain, and its function is to remove the small stones and sundries of the rice grain, so as to achieve the purpose of purifying the rice. Paddy rice is filtered through a filter-type vibrating screen, which can filter out small particles or stone particles larger than rice paddy. The disadvantage of the screening stone removal machine is that it cannot be filtered out.

The Working Principle of Specific Gravity Destoner

Specific gravity stone removal machine, also known as specific gravity classification stone removal machine, specific gravity selection machine, etc.; is a common equipment in rice processing plants. We all know that density and specific gravity are the physical properties of matter. Whether it is large or small, or the same size as grain, the same kind of stone and sand commonly found in nature have basically the same density and specific gravity. The working principle of the specific gravity stone remover is to separate the rice and the side stones according to the difference in the specific gravity and suspension speed of the rice and impurities, with the help of the upward airflow, so as to remove the stones and mud in the rice. The specific gravity stone removal machine is mainly used for grading and stone removal of wheat, rice, peanuts, corn, soybeans, etc., and can also be used for seed cleaning. 

According to the different mechanical wind power, the specific gravity stone removal machine is divided into several categories such as suction type, blow type and circulating wind. 

Grain and gravel are separated by means of vibrating motion, adjusting the airflow and adjusting the inclination of the screen surface. Grain is a granular body composed of particles with different particle sizes and specific gravity. When subjected to vibration or moving in a certain state, various particles will be divided into different levels according to their specific gravity, particle size, shape and surface state.

When the specific gravity destoner works, the material continuously enters the middle of the destoner screen from the feed hopper. Due to the vibration of the screen surface and the action of the airflow passing through the material layer, the porosity between the particles increases, and the material is in a fluidized state, which promotes automatic grading, the gravel with a large specific gravity sinks into the bottom layer and contacts the screen surface, and the grain with a small specific gravity floats to the top layer, and is driven by gravity, inertial force and continuous feeding, and slides to the net grain outlet; while the large specific gravity stone under the action of the inertial force of the screen surface vibration system and the air flow, the screen surface slides relative to the destoner, and moves to the selection area through the agglomeration area. In the selection room of the selection area, an air flow is introduced by the fan to blow back towards the front of the screen along the arc channel, and a small amount of grains contained in the stones are blown back to the aggregate area to avoid being discharged together with the stones.

The Working Principle of SQ50A Combined De-stoner

SQ50A Combined de-stoner is mostly common use de-stoning cleaning equipment for capacity 20-60 ton/day rice/corn/millet/quinoa milling plant. It is a smart design to combine vibrating cleaning and gravity de-stoning theory and technology into one machine. This combined de-stoner can be used in combination with a rice machine, or it can be used alone to remove sand and stone from paddy rice. Generally, the impurity content in the material is relatively high. The stone remover does not need a fixed bracket or base, it can be used as long as it is flat on the level ground, and it can also be flexibly used according to the needs of the workplace. When using, pour the material into the hopper, start the power supply, turn on the feed switch after the motor runs normally, the grain material flows into the vibrating screen evenly, and the impurities in the grain are cleaned out under the combined action of wind and vibration. Then, according to the principle of specific gravity, the sand and stones are moved to the direction of the stone discharge port and are separated, and the grain flows out from the net grain outlet. The stone removal machine is easy to operate and maintain, and only needs to lubricate the rotating parts such as bearings regularly. Under normal use, there is no need to replace parts for three or four years. It is especially suitable for small and medium-sized processing plants, flour mills, food processing plants, broken rice processing plants, and miscellaneous grain processing plants. 

After being processed by the destoner, the rice will become better without impurities, and then the rice will be selected by the color sorter before the rice is packed, and the quality will be higher. At the same time, the quality of the product is improved, and impurities such as moldy rice, black spot rice, belly white rice, watery yellow rice, small stones, and heterochromatic particles are removed by the color sorter, so that the quality of the rice is better.