Twin screw extruders are often used in plastic production and processing. In the actual production, twin screw extruders use their own advantages to improve the utilization rate of material resources and reduce the residual amount of material inside the extruder. Based on the continuous expansion of the production and processing scale, the modified plastics production and processing industry has put forward higher requirements for the technological performance of the twin screw extruder.
Among them, the improvement of cooling box and side feeder device of twin screw extruder can effectively improve the production efficiency.
Cooling box transformation
By adding a cooling box in the twin screw extruder, the improvement and optimization of the production process of the twin screw extruder are realized. In the actual extrusion production process, the humidity control exhaust device is added in the cooling box which greatly reduces the cooling loss of plastic products. Under the installation of the heat insulation board, the circulating air is formed to ensure that the products are in a good separation state and the heat dissipation effect is obvious. The chain in the cooling box optimizes the transmission mode of plastic products, realizes the synchronous operation of the cooling box and the twin screw extruder by adjusting the frequency of the main motor. With the support of the support rod, the distance between the plastic products and the contact box is shortened, the adhesion phenomenon is prevented, the actual production needs are met, the goal of improving the production quality of plastic products is realized, the diversification of plastic product production is guaranteed and the application scope and field of twin screw extruder are widened.
Improvement of side feeding device of twin screw extruder
The traditional side feeder is equipped with an exhaust port at the upstream. Under the support of the rotating force of the twin screw, the material is transported to the inside of the extruder. The material continues to move forward along the screw, is heated and melted, and is mixed under the action of the kneading block. However, when the amount of materials increases, the feeding port on one side is filled with materials and the other side has some space left. During the whole filling process, air is mixed which seriously affects the filling quantity.
1. Reduce the air inclusion in the filling process
An exhaust port is set at the upstream of the side feeder. The original screw is replaced by a lead screw. The side feeder hopper is divided into two parts. The front part is used for exhaust and the rear part is used for feeding. The lead screw supports the packing compaction during the packing transportation process, and smoothly discharges the mixed air through the front part of the hopper and finally discharges the air through the exhaust port upstream of the side feeder.
2. Free space is reserved at the feeding port on one side
By increasing the free space of the feeding port on one side, the actual filling quantity demand can be met. Based on this, a large-lead screw element is designed on the basis of the existing screw, an asymmetric screw element is set at the upstream of the screw side feeding port, a reverse conveying element is designed at one side of the screw side feeding port, and a reverse slotting element is designed at the other side. When the extruder is conveying materials, the materials enter the main feeding port and enter the extruder, and continue to be transported forward along the screw, melting by heat. When the material arrives at the asymmetric element, it is in the melting state. Under the action of the asymmetric element, the distribution state of the material changes significantly. One side of the feeding port carries out the reverse transportation, and the other side carries out the reverse transportation simultaneously. During the reverse transportation of the material, one side of the feeding port forms a cavity under the action of the reverse transportation element, which greatly increases the filling amount of the side feeding device.
3. Dual feeding system
The original single feeding mode was transformed into a dual feeding port simultaneous feeding mode to form a “dual feeding system”. During the actual transformation process, it was found that the gasket under the feeding system was displaced under the action of vibration. In the secondary transformation, a fixed bracket was added, effectively solving the vibration displacement problem, optimizing the filling process and links, and achieving the objectives of mixing, extruding, and shearing the main materials at a certain temperature, and the product quality is higher after production.