CN201721024U - Compound co-extruding conical screw extruder - Google Patents

Abstract

The utility model composite co-extrusion conical screw extruder is mainly composed of a feeding device, a machine barrel, a screw, an extruder head, a motor and a transmission device. There are nested inner and outer screws in the barrel, the helical directions of the inner and outer screws are opposite, and the inner and outer screws make opposite relative rotations. The two screws can be combined in three ways: the inner screw is a tapered screw and the outer screw is a parallel screw; the inner screw is a parallel screw and the outer screw is a conical screw; both the inner and outer screws are conical. After nesting, the screws are connected to the same extruder head. The utility model realizes single-machine double-layer co-extrusion, reduces the number of main machines of the co-extrusion unit, saves investment and equipment occupation area, and at the same time gives full play to the advantages of the conical screw, improving extrusion efficiency and product processing quality.

Description

Composite co-extrusion conical screw extruder

technical field

The composite co-extrusion conical screw extruder of the present invention can be used for composite co-extrusion of plastic products such as composite plates, films, pipes, sheets, optical fiber cables, and the like. the

Background technique

Composite co-extrusion is a processing method in which two or more polymers with different properties are co-extruded to form a multi-layer single product. Such as multi-layer sheets, films, plates, pipes, cables and multi-layer hollow containers. At present, most of the equipment used for composite co-extrusion is composed of two or more than two screw extruders, and different materials are extruded into the co-extrusion die for compounding. The equipment investment is large and complex, and the equipment occupies an area of Larger, especially the more layers of composite products, the more prominent this problem is, in addition, the molten materials from different extruder barrels need to be redistributed to meet the requirements of the designed product shape, the molten polymer is distributed In the process, different flow areas are caused, resulting in different melting temperature and residence time distribution, which not only has low efficiency, but also affects the appearance and quality of the product. the

Patent 200510105781.1 proposes a composite co-extrusion screw extruder. There are nested inner and outer screws in the barrel, the helical directions of the inner and outer screws are opposite, and the inner and outer screws make opposite relative rotations. There are first and second feeding ports on the barrel, the first feeding port corresponds to the feeding section of the outer screw, and there is an annular groove in front of the feeding section of the outer screw, which corresponds to the second feeding port of the barrel, and the outer part of the annular groove The annular surface and the inner surface of the barrel form a closed annular material storage room, and the bottom of the annular material storage room has a feeding hole for the second material to enter the inner screw, and the screw is connected to the same extruder head after nesting. One device can extrude two materials at the same time, avoiding or reducing the redistribution of molten materials, thereby improving the efficiency of composite extrusion and improving the quality of composite products. the

The diameter of the screw tail of the conical screw extruder is increased, and the feeding amount is increased, which improves the extrusion output of the extruder; the diameter of the screw tail increases also increases the bearing capacity of the screw; The large volume of bulk powder is also conducive to heat conduction, and it is easier to heat or cool the material; the diameter of the screw in the discharge section is small, the peripheral speed is small, the shear generated is low, the frictional heat is also small, and the risk of thermal damage Small resistance; the volume of the screw groove gradually decreases along the extrusion direction, and the material is gradually compressed, so that the screw groove is filled with the material faster, ensuring continuous and smooth plasticization of the material; under the same production capacity, the back pressure can be lower. the

Therefore, replacing the parallel screw in the patent 200510105781.1 with a conical screw can effectively play the advantages of the conical screw and the compound extruder, and obtain the compound co-extrusion conical screw extruder of the present invention. the

Utility model content

Traditional composite co-extrusion equipment is mostly composed of two or more extruders. The equipment occupies a large area and the heat lost from the barrel is too large. If the method of screw nesting is adopted, the purpose of one-machine co-extrusion can be realized, and the defects of traditional co-extrusion can be greatly reduced. Patent 200510105781.1 proposes a single-machine composite co-extrusion method, but the nested inner and outer screws are parallel screws, which are limited in processing PVC and other high-filling and heat-sensitive materials, and the output is not high. This problem can be well solved if at least one of them is extruded with a conical screw. In addition, the diameter of the conical screw tail increases, which improves the plasticizing output and bearing capacity; the screw diameter in the discharge section is small, and the shear is low, which reduces the risk of shear decomposition; the material is collected in the gradually decreasing screw channel It is better to compress and masticate. Therefore, the present invention combines the advantages of both the conical screw extruder and the composite co-extrusion screw extruder. the

In the present invention, nested inner and outer screws are installed inside the machine barrel, the helical directions of the inner and outer screws are opposite, and the inner and outer screws perform opposite relative rotation movements. There are first and second feeding ports on the barrel, the first feeding port corresponds to the feeding section of the outer screw, and there is an annular groove in front of the feeding section of the outer screw, which corresponds to the second feeding port of the barrel, and the outer part of the annular groove The annular surface and the inner surface of the barrel form a closed annular material storage room, and the bottom of the annular material storage room has a feeding hole for the second material to enter the inner screw, and the screw is connected to the same extruder head after nesting. A heating ring is installed on the outer circumference of the barrel to heat the screw and the barrel. the

The above-mentioned external screw is driven by a motor through a reduction box for rotational movement, and the internal screw is fixed on the stator or driven by another motor alone, so that the internal and external screws perform relative rotational movement in the opposite direction. the

The above-mentioned internal and external screws can be combined according to the different characteristics of the materials and processed products and the processing conditions. the

a. The outer screw adopts conical screw, and the inner screw adopts parallel screw. the

b. The outer screw adopts parallel screw, and the inner screw adopts conical screw. the

c. Conical screws are used for both internal and external screws. the

The effect of the present invention: due to the inner and outer screws with reverse rotation and opposite direction of rotation nested in the outer screw, the inner and outer screws can extrude the same or different materials at the same time, the relative rotational speed of the inner screw is the sum of the actual rotational speeds of the inner and outer screws, and the relative The speed is greatly increased, and the conveying capacity and output of the internal screw are also increased accordingly; when extruding the same material, one extruder can be equivalent to the effect of two single-screw extruders, which improves the output and extrusion efficiency; When extruding different materials, it can realize single-machine double-layer co-extrusion, and can also reduce the number of hosts of multi-layer co-extrusion units, saving investment and equipment footprint, and has high extrusion efficiency, simple operation and simple maintenance. In addition, the single-machine double-layer co-extrusion compound head is used, and the material will not enter from the side, which can make up for the shortcomings of the traditional co-extrusion technology, avoid the trace of "welding line", and improve the processing quality of the product. According to the different characteristics of the materials and processed products and the processing conditions, etc., the above three screw combinations (a, b, c) can be carried out to give full play to the advantages of the conical screw, improve the plasticizing effect, and obtain better products. the

Description of drawings

Figure 1 is a structural schematic diagram of a composite co-extrusion conical screw extruder

Figure 2 is a schematic diagram of both internal and external screws using conical screws

Figure 3 is a schematic diagram of a parallel screw for the inner screw and a conical screw for the outer screw

Figure 4 is a schematic diagram of the inner screw using a conical screw and the outer screw using a parallel screw

Fig. 5 is A-A sectional view among Fig. 2, and Fig. 3, the corresponding structure of 4 is similar

specific implementation plan

The composite co-extrusion conical screw extruder of the present invention mainly comprises: motor 11, reduction box 2, machine barrel 5, outer screw 7, inner screw 8, stator 1, first feeding port 4, second feeding port 3, machine barrel Heating ring 6, internal screw heating device 9, die 10. the

Working principle (see Figure 1): When the motor drives the outer screw to rotate, it produces opposite rotational motion with the inner screw (fixed or driven by the motor alone). A material is fed from the hopper 4, and enters the external screw for extrusion, transportation, plasticization, and melting. Another material is added from the hopper 3, and enters the closed material storage room formed by the annular groove at the front end of the outer screw and the inner surface of the barrel, distributed along the circumferential direction of the outer screw annular groove, and enters from the feeding hole 12 of the annular storage room. internal screw. The material entering the inner screw is extruded, conveyed, plasticized and melted under the action of the rotation of the outer screw and the action of the core heating rod. Since the rotation direction of the inner screw is opposite to that of the outer screw, and the helical directions of the inner and outer screws are also opposite, the two materials are transported in the same direction along the screw, and then merged into the compound head 10 of the same extruder for extrusion molding. the

The present invention has three screw combinations:

a. The outer screw adopts conical screw, and the inner screw adopts parallel screw. (Figure 2 and Figure 5)

b. The outer screw adopts parallel screw, and the inner screw adopts conical screw. (image 3)

c. Conical screws are used for both internal and external screws. (Figure 4)

Corresponding screw combinations can be selected according to the different characteristics of materials and processed products as well as the processing conditions. Good products have been obtained, and lower energy consumption has been achieved. the

Claims (4)

1. compound co-extrusion conical screw extruder, mainly by feeding device, machine barrel, screw rod, machine head port mould and motor and transmission device are formed, it is characterized in that: nested interior external screw rod is housed in the machine barrel, the hand of spiral of interior external screw rod is opposite, and interior external screw rod is made reverse relative rotary motion, have first charge door and second charge door on the machine barrel, first charge door is corresponding with the external screw rod feeding section, have cannelure before the external screw rod feeding section, cannelure is corresponding with second charge door of machine barrel, the outer ring surface of cannelure and machine barrel inner surface constitute the closed ring storage compartment, annular has at the bottom of the storage compartment and makes second kind of material enter the charging hole of inner screw, connects same extruder head behind the nested screw rod.

2. compound co-extrusion conical screw extruder according to claim 1, it is characterized in that: external screw rod is rotated by motor-driven, and inner screw is fixed on the stator or separately by another motor-driven, external screw rod is made reverse relative rotary motion in making.

3. compound co-extrusion conical screw extruder according to claim 1 is characterized in that: installation kit is wrapped with heating collar on the machine barrel excircle, is screw rod and machine barrel heating.

4. compound co-extrusion conical screw extruder according to claim 1 is characterized in that: inside and outside two screw rods can carry out the combination of conical screw and parallel screw.Can inner screw be conical screw, external screw rod be a parallel screw, can inner screw be parallel screw also, and external screw rod is a conical screw, can also be conical screw by interior external screw rod.

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