Classification and basic parameters of extruder

Classification and basic parameters of extruder

1. Extruder classification

There is no unified regulation on the classification method of extruder, which can be divided according to the number of screws or the function of extruder. According to the number of screws, extruders can be divided into single screw extruder, twin screw extruder and multi screw extruder; According to the function of extruder, it can be divided into general single screw extruder, exhaust extruder, foaming extruder, feed extruder, etc.

For example: single screw extruder

Single screw extruder is one of the most widely used general-purpose extruders. It is characterized in that the extrusion system is composed of a screw and a barrel. As long as the screws with different structural forms are replaced, the extruder can complete the extrusion of various thermoplastic plastics. Scope of application: it is suitable for mixing, plasticizing and extrusion of high molecular polymers such as engineering plastics, modified plastics and color masterbatch. At the same time, it has the characteristics of uniform dispersion, plasticizing and coloring, filling and modification. It is also suitable for laboratory test and quality control, teaching research and small-scale production.

2. Basic parameters

(1) Screw diameter refers to the outer diameter of the screw thread, expressed in D, in mm.

(2) The length diameter ratio of the screw refers to the ratio of the length of the threaded part of the screw to the diameter of the screw, expressed in L / d.

(3) The speed range of the screw refers to the maximum speed and the minimum speed when the screw works, expressed in nmx ~ Nmin.

(4) Motor power refers to the power of the motor driving the screw to rotate, expressed in P, in kW.

(5) Barrel heating power refers to the electric power when the barrel is heated by resistance, in kW.

(6) The number of barrel heating sections means that the barrel heating is controlled by several temperature zones.

(7) Extruder output refers to the production capacity of the extruder in unit time, expressed in Q, and the unit is kg / h.

(8) Nominal specific power refers to the comprehensive index of motor power required for the quality V of plastic products produced by the extruder per hour, expressed in P, i.e. p '= P / QMA, in kW / (kg / h).

(9) Specific flow refers to the quality of plastic products produced by each rotation of the screw. It can reflect the production efficiency of the extruder, expressed in q = q real / N, and the unit is (kg / h) / (R / min).

(10) Center height refers to the height from the center line of the screw in the barrel of the extruder to the ground, expressed in H, in mm.