In plastic granulation production, particle density, surface gloss, and production stability are often closely related to the design of the exhaust system. Whether the screw barrel is equipped with single exhaust or dual exhaust is not simply a difference in quantity, but rather tailored to different needs
raw materialDifferentiation plan for characteristics and quality requirements.
The core function of exhaust port
The raw materials are heated and plasticized during the screw conveying process, producing a certain amount of water vapor and volatile substances. If these gases are not discharged in a timely manner and mix into the interior of the melt, it will cause problems such as bubbles and insufficient density of particles, and in severe cases, it may also cause breakage, affecting continuous production.
Therefore, the core function of the exhaust port can be summarized as: efficiently separating and discharging the gaseous substances released during the plasticization process, ensuring that the melt is homogeneous and dense.
What is the difference between single exhaust and dual exhaust?
Single exhaust structure
The single exhaust design only has one exhaust port, with a relatively simple structure and low equipment cost. Suitable for raw materials with low moisture content and high cleanliness, a single exhaust port can meet the exhaust needs, with high cost-effectiveness.
Dual exhaust structure
Dual exhaust design with two exhaust ports, clear division of labor, and step-by-step deactivation:
First exhaust port: main exhaust. Located in the early stage of the melting section, responsible for extracting a large amount of water vapor and initial volatile compounds released after heating the raw materials, and bearing the majority of the exhaust load.
Second exhaust port: deep detachment. Set in the plasticization and homogenization stage, residual trace gases are further extracted, which is equivalent to a "precision treatment". The two-stage exhaust system works together to effectively improve particle density and product quality, making it suitable for production scenarios with high exhaust requirements.
Selection Suggestions
Based on raw material and quality requirements
✅ ️Single exhaust applicable scenarios:Clean scraps and pre dried raw materials have low moisture and volatile content, low exhaust requirements, and a production scenario that pursues cost-effectiveness.
✅ ️Dual exhaust applicable scenarios:Raw materials with high moisture content such as recycled materials and washed materials, or production scenarios with high requirements for particle density and finished product value.
