Single screw extruder: suitable for single material and general livestock and poultry collaborative feed.
Twin screw extruder: generally used in the production of high value-added aquatic and pet feed, such as eel, turtle, and juvenile fish feed, because the prices of these products sold in the market are sufficient to repay the cost of manufacturing products using twin screw technology; In addition, some special aquatic feed, such as particulate aquatic feed (with a diameter of 0.8~1.5mm), high fat aquatic feed, and feed with small production volume but constantly changing formula, also need to be produced using a twin screw extruder.
It should be clarified that the above differences are not certain. For example, we suggest using twin screws to produce aquatic feed, but now many companies use single screws to produce aquatic feed. There are differences in the use of the two for aquatic feed. In short, compared to single screw, double screw has the following advantages:
① The adaptability of raw materials is wider, which can adapt to the processing of high viscosity, low viscosity, high oil content, high moisture or viscosity, oily, very wet raw materials, and other materials that may slip in single screw (SSE).
② There are fewer restrictions on the particle size of raw materials, which can adapt to the processing of raw materials from micro powder to coarse powder particles and single screw processing of materials with particle sizes outside the specific range.
③ The material flow inside the barrel is more uniform, and steam, water, etc. can be added to achieve the desired effect of the product.
④ The internal and external quality of the product is better, which can achieve a very good homogeneous state and make the molecular structure of the material evenly arranged. The surface is smooth during the extrusion process. The product particles have high uniformity and good uniformity.
⑤ The ripening and homogenization effect is better, usually with a starch ripening degree of over 95%, which enables the processed aquatic feed to maintain stability in water, prevent loss of product nutrients, and be easy to digest and absorb.
⑥ Higher yield under equal power. Good mixing performance enables timely homogenization of the heat received by the material, accelerates the maturation degree of the material, reduces fluctuations in material temperature, and improves the output of extruded products.
⑦ The product diversity and adaptability are wider, and it can process micro aquatic feed, high oil formula, high moisture content, high adhesion products, and multi color, sandwich type, and special shaped products.
⑧ The process operation is more convenient, and the spindle speed can be adjusted according to the needs of the processed product. Due to the self-cleaning feature, cleaning is very convenient, and there is no need to disassemble the equipment after each processing.
⑨ Vulnerable parts wear less. A common misconception is that a single screw has less wear. In fact, during the twin screw extrusion process, due to the stable material transportation and material flow characteristics, the wear of the material on the screw and the inner sleeve of the barrel is smaller than that of a single screw. Although the number of screws is one more set, the cost of accessories is still lower than that of a single screw.
⑩ The production cost is lower. Due to the good operational stability of the twin screw model, there are fewer start-up costs, less water and gas waste, less labor costs, high heat transfer efficiency, high yield, and high electricity output indicators in the feed processing process. In addition, the cost of accessories is also low, and the final production cost is still much lower compared to a single screw.
It is precisely because of the many advantages of twin screw compared to single screw in producing aquatic feed that we advocate prioritizing the selection of twin screw extruder when conditions permit in all aspects.
The following are the precautions to be taken when using a twin screw extruder:
1. Operation safety:
-Before operating the twin screw extruder, it is necessary to be familiar with the equipment’s operating procedures, safety precautions, and the use of emergency shutdown devices.
-Operators should wear corresponding protective equipment to avoid accidents and potential injuries during operation.
-Ensure the safety of the working environment around the equipment and prevent accidents such as slipping and collision.
2. Equipment maintenance:
-Regularly maintain and maintain the twin screw extruder, including cleaning, lubrication, tightening bolts, etc. Ensure that the equipment is in good working condition.
-Regularly inspect easily worn components such as screws, washers, and assemblies, and replace them in a timely manner to ensure the normal operation of the equipment.
-Develop corresponding maintenance plans based on the frequency of equipment use and working environment to ensure long-term stable operation of the equipment.
3. Adaptability of raw materials:
-Twin screw puffing machines have high requirements for raw materials, and different raw materials may require different puffing process parameters and operating methods.
-When selecting equipment, it is necessary to ensure that the model and specifications of the equipment are suitable for the required processing technology based on the characteristics of the raw materials and processing requirements.
4. Temperature and speed control:
-Temperature and rotational speed are important parameters that affect the processing effect of twin screw extruder, and they require reasonable adjustment and control.
-Temperature control should be adjusted according to different raw materials and processing requirements. Excessive temperature may lead to excessive maturation or burning of raw materials, affecting product quality.
-The control of rotational speed also needs to be adjusted reasonably based on raw materials and processing requirements. High or low rotational speed may affect the processing effect and product quality.
5. Material quantity and process control:
-The control of material quantity needs to be adjusted according to the specifications of the equipment and the characteristics of the raw materials. Excessive material volume may cause equipment blockage, while excessively low material volume can reduce processing efficiency.
-The control of the process requires a reasonable arrangement of the feeding and discharging sequence of raw materials, ensuring the uniform distribution of raw materials and the normal discharge of output, and avoiding blockage and mixing phenomena.
6. Cleaning and hygiene:
-When using a twin screw extruder, attention should be paid to the cleanliness and hygiene management of the equipment, and regular cleaning of residues and dust inside the equipment should be carried out to prevent cross contamination and bacterial growth.
Post time: Jun-29-2023