Types of laboratory twin-screw extruders
1. According to the relative position of the two axes
Parallel twin-screw extruder: The axes of the two screws are parallel to each other. It is widely used and suitable for a variety of processes such as polymer blending, modification, and granulation. It can achieve efficient mixing, plasticization, and transportation of materials.
Conical twin-screw extruder: The screw is conical, and the diameter of the two screws in the barrel gradually increases from the feed end to the discharge end. It has the characteristics of forced extrusion, wide adaptability, and long life. It is suitable for processing powder materials and is widely used in the production of products such as pipes and plates.
2. According to the degree of meshing of the two screws
Meshing twin-screw extruder: The two screws mesh with each other, which can be divided into partial meshing and full meshing. It can produce strong shearing, mixing and conveying effects, has good self-cleaning performance, and can be used for high-viscosity material processing, reactive extrusion, etc.
Non-meshing twin-screw extruder: The two screws do not mesh with each other, and the flow of materials between the screws is relatively simple. It mainly relies on the action of the screw and the barrel for conveying and mixing. It is suitable for some occasions that do not require high shearing and require large-volume conveying.
3. According to the rotation direction of the two screws
Co-rotating twin-screw extruder: The two screws rotate in the same direction, the flow of materials between the screws is complex, and the mixing effect is good. It has the characteristics of high speed and high output. It is often used in plastic modification, masterbatch production and other fields.
Counter-rotating twin-screw extruder: The two screws rotate in the opposite direction, divided into inward and outward rotation. The shear force is large, and the crushing and plasticizing effect of the material is good. It is suitable for processing some difficult-to-process materials, such as high-filling materials.
4. According to the screw rotation speed
High-speed twin-screw extruder: The speed is usually high, generally above 300 rpm, which can improve production efficiency and enhance the shearing and mixing effects of materials, but it has high requirements for the adaptability and stability of the material. It is often used in occasions with high requirements for production efficiency and mixing effects.
Low-speed twin-screw extruder: The speed is relatively low, generally below 100 rpm. The material stays in the barrel for a long time, and the shearing effect is mild. It is suitable for processing heat-sensitive and high-viscosity materials, and can reduce the risk of material overheating and degradation.
5. According to the structure of the screw and barrel
Integral twin-screw extruder: The screw and barrel are an integral structure, with a simple and compact structure and low manufacturing cost, but it is more difficult to repair and replace the screw and barrel. It is suitable for some occasions that require simple equipment structure and a relatively stable use environment.
Combined twin-screw extruder: The screw and barrel adopt a building block design and are composed of multiple combinable components. The screw and barrel structure can be flexibly combined according to different process requirements to achieve different process functions, and it is easy to repair and replace, but the manufacturing cost is high. It is currently the type commonly used in laboratories.
The price of laboratory twin-screw extruder
The price of laboratory twin-screw extruder is affected by factors such as type, brand, specification, configuration, etc. The approximate price range is as follows:
Small desktop parallel co-rotating twin-screw extruder: Generally, the screw diameter is about 12-20mm, and the price is usually around 4000-120000 yuan. For example, 20 spot air-cooled strand experimental twin-screw extruders, small air-cooled strand twin-screw plastic granulators, cost 4288 yuan.
Conventional specification parallel twin-screw extruders: The screw diameter is 25-36mm, and the price is generally 120000-350000 yuan. For example, the XH-433-25 laboratory twin-screw extruder granulator costs 186,000 yuan.
Conical twin-screw extruders: The price is relatively high, small ones may be around 400,000 yuan, and medium and large ones may cost more than 500,000 yuan.
Imported brand high-end twin-screw extruders: such as some products of Thermo Fisher, the price may be as high as millions of yuan. For example, Thermo Fisher’s HAAKE Process 11 micro twin-screw extruder has a reference transaction price of RMB 1-8,000,000.
