In the global market, the demand for high - quality sunflower seed oil is on the rise. To meet international standards and customer requirements, the choice of processing equipment is crucial for oil mills. This article provides a comprehensive guide to the selection of semi - automatic and fully automatic production lines for export - grade sunflower seed oil processing equipment.

1. Pre - treatment Stage

The pre - treatment stage mainly includes cleaning and shelling. Cleaning equipment plays a vital role in removing impurities from sunflower seeds. For example, a well - designed cleaning machine can remove up to 95% of the impurities such as dust, stones, and broken seeds. The principle of impurity removal is based on the difference in physical properties such as size, density, and shape between the seeds and impurities. As shown in Figure 1 , the cleaning equipment uses a combination of sieving and air separation. The sieving process separates larger and smaller impurities according to the size of the mesh, while the air separation removes lighter impurities by using the force of airflow.

Shelling efficiency has a significant impact on the oil yield. High - quality shelling equipment can achieve a shelling rate of over 90%. When the shelling rate is increased, the contact area between the kernel and the pressing equipment during the pressing process is larger, which is conducive to improving the oil yield. However, in the shelling process, some common faults may occur, such as low shelling rate and high kernel breakage rate. For the low shelling rate, it may be caused by the inappropriate adjustment of the shelling gap. Generally, the shelling gap should be adjusted to 0.5 - 1.0 mm according to the size of sunflower seeds. If the kernel breakage rate is too high, it may be due to the excessive rotation speed of the shelling machine, and the rotation speed should be controlled within 800 - 1200 r/min.

2. Pressing Process

There are two main types of pressing equipment: screw pressing and hydraulic pressing. Screw pressing equipment is widely used because of its high continuous operation ability. It can process 5 - 10 tons of sunflower seeds per day. The working principle of screw pressing is to use the rotation of the screw to generate pressure, gradually squeezing the oil out of the seeds. This type of equipment is suitable for medium - and large - scale oil mills. As shown in Figure 2 , the screw presses the seeds step by step, and the oil is discharged through the gaps in the pressing chamber.

Hydraulic pressing equipment, on the other hand, is more suitable for small - scale production. It can process 1 - 3 tons of sunflower seeds per day. The advantage of hydraulic pressing is that it can provide a more stable and uniform pressure, which is beneficial to obtaining high - quality oil. However, its production efficiency is relatively low compared with screw pressing.

When it comes to semi - automatic and fully automatic production lines, there are significant differences in labor cost, stability, and production capacity. In a semi - automatic production line, manual operation is required in some key steps, such as feeding and discharging. The labor cost accounts for about 30% of the total production cost. Although the investment cost of semi - automatic equipment is relatively low, its production capacity is limited, usually ranging from 3 - 8 tons per day. In contrast, the fully automatic production line has a high degree of automation, which can significantly reduce labor cost. The labor cost only accounts for about 10% of the total production cost. It can operate continuously and stably, with a production capacity of 10 - 20 tons per day. For example, in the fully automatic screw pressing production line, the feeding, pressing, and discharging processes are all automatically controlled, which not only improves production efficiency but also ensures the stability of product quality.

3. Filtration and Finishing of Finished Products

After pressing, the crude oil needs to be filtered to obtain high - quality sunflower seed oil. There are two main filtration methods: physical filtration and precision filter element technology. Physical filtration mainly uses filter screens with different meshes to remove large - particle impurities in the oil. Precision filter element technology, on the other hand, can remove finer impurities and improve the clarity of the oil. As shown in Figure 3 , the precision filter element can filter out impurities as small as 1 - 5 microns.

To detect the clarity of the oil, methods such as visual inspection and turbidity measurement can be used. Visual inspection is a simple and intuitive method, but it has certain subjectivity. Turbidity measurement is a more accurate method. Generally, the turbidity of high - quality sunflower seed oil should be less than 1 NTU. By using appropriate filtration technology and quality control methods, the quality of sunflower seed oil can be effectively improved, making it meet international market standards.

In conclusion, by understanding the key points of each stage of sunflower seed oil processing, oil mill managers and operators can make more informed decisions when selecting processing equipment. Whether it is the pre - treatment stage, pressing process, or filtration and finishing of finished products, each link is crucial for improving the oil yield and product quality. To learn more about the technology and selection guide of export - grade sunflower seed oil processing equipment, welcome to visit our technology column.