What role does the air screen cleaner play in a sesame processing line?

In the comprehensive sesame cleaning process, the double air screen cleaner serves as the primary piece of core cleaning equipment, handling the tasks of initial cleaning and preliminary grading. Sesame seeds are small and lightweight, and the raw material often contains a significant amount of impurities such as stalks, pods, dust, fine sand, and shriveled husks. If the initial cleaning is inadequate, the workload on downstream gravity-based destoning and precision sorting equipment increases sharply, directly reducing the processing capacity of the entire line and compromising the quality of the finished product. By combining vibratory screening with a dual-air-channel separation system, the machine separates impurities of varying sizes and materials of differing weights, providing consistently high-quality pre-processed material for subsequent stages; it is thus an indispensable foundation for the sesame cleaning production line.

In terms of operating principles, the double air screen cleaner integrates vibratory screening with independent dual-air-channel separation. In the vibratory screening section, a motor drives an excitation mechanism that causes the screen box to oscillate at a set amplitude and frequency. With the screen surface installed at an optimal angle, the raw sesame moves forward via a continuous hopping and sliding motion, allowing for material grading based on screen aperture size. The specialized long-hole screens are arranged in two layers: the upper screen has larger apertures to catch bulky impurities larger than the sesame seeds, while the lower screen has smaller apertures that allow fine sand and soil to pass through while retaining the intact sesame seeds. The air separation section features two independently adjustable fans, creating a dual-channel airflow system. The first airflow targets the material at the feed inlet, breaking up clumps of sesame mixture and removing lightweight impurities such as pods, broken stalks, and dust. The second airflow processes the material after screening, further removing shriveled seeds, empty husks, and lightweight, moldy seeds. The airflow rates of the two air channels can be adjusted independently. Given the characteristics of sesame seeds—specifically their small size and low mass—air velocity is strictly controlled to prevent excessive speeds from suctioning away intact seeds along with light impurities, while avoiding speeds that are too low to effectively separate those impurities. Screening sorts materials based on geometric dimensions, whereas air separation sorts them based on differences in specific gravity; the two methods work in tandem to achieve dual-stage sorting by both size and specific gravity.

In the context of the sesame cleaning production line's overall workflow, raw material is evenly fed via a bucket elevator into the inlet of the dual-air-screen cleaner. A variable-frequency feeding mechanism regulates the flow rate, ensuring the material is spread in a uniform, thin layer across the top screen surface to prevent piling or uneven thickness. Upon entering the upper screen, the material moves forward under vibration; large impurities—such as stalks, pod husks, and large soil clods—cannot pass through the screen apertures and are discharged through the large-impurity outlet. Meanwhile, sesame seeds, fine sand, shriveled grains, and other smaller materials pass through the upper screen onto the lower screen. The lower screen vibrates continuously, allowing fine sand and soil particles to fall through into the bottom impurity hopper for discharge, while intact sesame seeds remain on the screen and are conveyed forward. During this process, a primary air-separation stage directs airflow at the material layer near the inlet, extracting floating dust and broken pod husks into the dust collection ducting. After screening, the material reaches a second air-separation zone where another airflow removes lightweight materials—such as shriveled seeds and insect-damaged, hollow grains—directing these light impurities into the dust collection system. The cleaned sesame seeds, having undergone screening and dual-stage air separation, are discharged from the main outlet and conveyed to the next stage: a gravity-based destoner. The entire process operates continuously, with all dust-generating points connected to a negative-pressure dust removal system to prevent dust dispersion and improve the workshop working environment.

Within the sesame production line, the dual-air-screen cleaner plays a pivotal role by performing the initial cleaning of raw material and handling the bulk of the impurity removal work for the entire line. Raw sesame seeds procured from the market contain a complex mix of impurities, with dust and broken shells accounting for the vast majority. If fed directly into gravity-based separation equipment, sand and soil can clog the screen surfaces, causing the gravity stratification process to fail and significantly reducing the efficiency of stone removal. Using a dual air-sieve system to pre-remove large debris, fine dust, and light impurities effectively lightens the workload on downstream gravity destoners and graders, extends the service life of subsequent equipment, and ensures stable, full-capacity operation of the entire production line. Additionally, the equipment performs a material grading function, conducting preliminary sorting to produce semi-finished sesame with relatively uniform particle sizes; consistent feed material is a prerequisite for achieving effective gravity stratification. If the material entering the gravity separation stage varies significantly in size, it becomes difficult to establish stable stratification based on density, thereby severely compromising the separation of stones (especially those similar in size to the seeds) and the removal of shriveled grains.

Adjusting equipment operating parameters is crucial given the specific characteristics of sesame seeds. Screens with elongated apertures are preferred; these better accommodate the slender shape of sesame seeds and are less prone to clogging. The equipment's vibration amplitude must also be matched to the specific processing conditions: insufficient amplitude prevents the material from spreading adequately, while excessive amplitude can cause seed breakage. A stable feed rate is essential; fluctuations disrupt the screening and air-separation processes, thereby compromising impurity removal—which is precisely why variable-frequency control is incorporated into sesame production lines.

In actual production, the operational status of the dual-air-stream screen cleaner directly determines the stability of the entire production line. When impurity levels in the raw material fluctuate, operators can simply adjust the feed rate, airflow volume, and screen box amplitude to accommodate sesame raw materials of varying origins and qualities. Beyond initial cleaning, the machine integrates seamlessly with downstream equipment; by effectively performing pre-treatment, it enables subsequent processes—such as gravity separation, magnetic separation, and color sorting—to operate at peak performance, collectively achieving a final product purity of 99.5%.

In summary, as a key upstream component of the sesame cleaning line, the double air screen cleaner utilizes a combination of vibratory screening and dual-channel air separation to remove large debris, fine sand/soil, and light, shriveled impurities in bulk. It performs preliminary material grading, ensuring a uniform and stable feed for the subsequent gravity separation stage. The machine significantly reduces the processing load and failure risk for downstream equipment while minimizing sesame breakage and—when paired with a dust collection system—enabling environmentally friendly production. With adjustable parameters suitable for both white and black sesame varieties, the double air screen cleaner plays an indispensable role in pre-treatment for both domestic food processing and export-oriented lines, serving as a core unit in complete sesame cleaning systems.