Practical tips for twin screw extruder
Practical tips for twin screw extruderTwin-screw extruder is a commonly used equipment of modified plastic manufacturers. Today we introduce some small details that can improve the function of twin-screw extruder. The techniques introduced in this article include three aspects: equipment modification, equipment maintenance and operation standards. Most of the feeding section of the barrel with insulation gasket between the feeding section and the flange of the second section is water-cooled, and it is determined by the flange and the barrel (heated) of the second section, the heat can be continuously from the high temperature The cylinder is transferred to the cold cylinder. As a result, the second-stage barrel cannot maintain a satisfactory temperature. Generally, the operator sets a temperature of 180°C in the second section of the barrel, but due to the heat loss in the feeding section, the practice stability generally does not exceed 135°C.
The simple solution is to add 1-2 1mm thick heat-insulating gaskets between the feeding section and the second section of the cylinder flange, and replace the heat-insulating gaskets every few years, because the heat-insulating gaskets are aging and degraded And the tendency to shrink. Replacing the twin-screw extruder cooling system with a high-pressure cooling system turbulent flow in the water pump can cause more tube wall heat exchange than laminar flow.
The turbulent flow in high-pressure transmission has a high degree of lateral momentum exchange, which breaks the boundary layer. The resulting violent fluid movement caused a much greater thermal communication between the tube wall and the fluid. Extruder cooling circulation system is generally 20-60psi pressure. In order to reach the turbulent flow, a pressure of 120 PSI is reached. Almost all the cooling system components (hose and valve) of the extruder have to be upgraded to 150PSI to be satisfied with the safety factor of 120PSI. After the transformation is completed, the cooling system can discharge a lot of heat in time.
Twin-screw extruder is suitable for modification and addition of feed volume. Side feed is generally used to feed filler into the twin-screw extruder. Many processors need to make very high fillers, which often have a very low bulk density. The final filling volume is constrained by the following factors: the volumetric feeding capacity of the side feed and the volumetric feeding capacity of the main screw of the extruder. The volumetric feeding ability depends on the free volume of the side feeder and the main screw and the speed of the two screws.
If a kind of material can flow into the storage drum without being resisted by the main screw during the test, then the feeding speed of this kind of material can reach very well. If the side feeder is directly connected to the main screw, the amount of data that the auxiliary screw can withstand will be restricted. Therefore, the main machine screw has a long-pitch threaded element that extends 2D-4D in length downstream from the side feed port. This will allow the melt to quickly pass through the side feed port, so that the filler will be eaten by the main screw to a great extent. If the screw design of the main engine causes any accumulation of side feed materials, the feed amount of the filler will be severely restricted.
Promises the ability to exhaust gas from the extruder. The purpose of the exhaust is to make the air simply escape, and also to maintain the filler not to escape a lot from the exhaust port. The equipment is to open an exhaust port upstream of the side feed port. Sometimes, a small semi-slit is opened in the upper part of the side feeder for exhaust. There are some other factors to consider: In the case of the aspiration of the feeder, the feed screw should be installed as close as possible to the top of the side feed port to reduce the height of the feed. If some loose material flows through the air, then it may become filled with air, so that it will greatly reduce the false density after falling.
If you want to know more about it please do not hesitate to
contact me. WhatsApp:+86-15966835076.
