CN102225315A - Three-rotor continuous mixing unit with rotors arranged in a straight line - Google Patents

Abstract

The invention provides a three-rotor continuous mixing unit with rotors arranged in a straight line. The mixing unit mainly comprises a mixing part and a discharging part and can adopt a single-band or dual-band mode; wherein the mixing part mainly comprises a charging device, a cylinder, three rotors, heating and cooling devices and a transmission device; the center lines of the three rotors are in the same plane and the three rotors are arranged in parallel; the projection lines vertical to the plane are arranged in a straight line; the mixing rotors must be provided with charging segments and mixing segments; the screw conveying structure is adopted to the rotors on the charging segments; efficient cam-shaped, S-shaped or four-wing-shaped mixing rotor structure is adopted to the rotors on the mixing segments; when the mixing unit adopts the single-band mode, the tail ends of the rotors adopt the screw structure and pressure is created to convey the materials to the head; and when the mixing unit adopts the dual-band mode, the mixed materials enter into next band of screw extruder via a valve and pressure is created to convey the materials to the head; the mixing unit in any one of the two modes adopts the head fit for the cavity for pelleting or forming; a melt pump can be connected in front of the head; and the three rotors can rotate at the same speed or different speed and form a plurality of shearing, drawing and kneading zones during rotation, and exchange of materials among the rotors is more frequent, thus effectively improving the plasticating, melting and dispersing properties of equipment, shortening the processing time and improving the yield. The mixing unit can be used in such processes as mixing, pelleting and the like during processing rubbers, coatings, propellants, explosives, paper pulp, plastics, food, medicaments, feeds and the like.

Description

Three-rotor continuous mixing unit with rotors arranged in a straight line

technical field

The invention relates to a three-rotor continuous mixing unit with rotors arranged in a straight line, which can be used in the processes of mixing and granulation in the processing of rubber, paint, propellant, explosive, paper pulp, plastic, food, pharmacy, feed and the like.

Background technique

Mixing is a key process link that determines the performance of polymer products, especially for high viscoelastic materials such as rubber. The uniformity and stability of material mixing is the key to ensure the quality of polymer products. The realization of uniform mixing mainly depends on mixing technical equipment, including open mixer, internal mixer, double-rotor continuous mixer and screw extruder. Industrially, screw extruders are mainly used for plasticizing plastics, food and thermoplastic elastomers, while the other three are mainly used for mixing complex materials such as rubber, coatings, explosives and propellants. Open mills and internal mixers are batch mixing equipment, which are not only inefficient, but also difficult to achieve the same mixing quality of different batches of materials.

The double-rotor continuous mixer combines the excellent mixing characteristics of the internal mixer, and also operates continuously, and is widely used in industrial mass production. It is mainly composed of barrel, rotor, unloading device and other parts. The mixing chamber on the barrel is two interconnected holes with a circular cross section, and the materials are sheared, pulverized, kneaded and mixed by the rotor in the mixing chamber. The non-meshing counter-rotating rotor is mainly composed of feeding section, mixing section and discharging section. The feeding section of the rotor is like two non-meshing twin-screws. Driven by the threads of the feeding section of the rotor, the material fed from the feeding port reaches the mixing section. The helix angles on the surface of the mixing section of the rotor are different and the threads are staggered, where the materials are melted, mixed and plasticized. The unloading device can control the opening of the unloading door to achieve the purpose of controlling the residence time of materials in the mixing chamber.

Patent 200620154843.8 develops a parallel three-screw extruder arranged in a line on the basis of a parallel twin-screw extruder. Three screws are arranged in parallel to form two kneading zones. Compared with the twin-screw extruder, the three-screw extruder has the characteristics of friction shear and positive displacement conveying of two meshing zones, and the material has a larger contact area with the screw. Good mixing, good heat transfer, high melting capacity, excellent exhaust ability and better temperature control, and has lower energy consumption.

Similarly, on the basis of the double-rotor mixer, three rotors arranged in a straight line form a new mixer, which not only increases the output and saves energy, but also significantly improves the mixing effect.

Contents of the invention

Different from the traditional double-rotor kneader, the continuous kneader of the present invention adopts a three-rotor kneading structure in which the rotors are arranged in a straight line, as shown in Fig. 1 . There are three rotors in the mixing part, the centerlines of the three rotors are arranged in parallel in a plane, and the projections perpendicular to the plane form a straight line, that is, they are arranged in a straight line, which is equivalent to two pairs of double rotors for mixing . Further, for continuous mixing, the mixed material must be transported to the machine head for granulation or molding, that is, a discharge part is required in addition to the mixing part. In this way, the three-rotor continuous mixing unit consists of a mixing part and a discharging part. The complete unit formed for this purpose can be either single-stage or double-stage.

The single-stage three-rotor continuous mixer is that the rotor is composed of a non-meshing screw feeding section, a mixing rotor section and a screw discharging section in turn. The material is continuously added and mixed, and is forced to be discharged to the machine head through the conveying section for granulation or molding. , The cavity structure of the head depends on the shape of the exported product. In order to increase the outlet discharge pressure, a gear pump can also be connected in front of the machine head.

The two-stage three-rotor continuous mixing unit is shown in Figure 1, which mainly consists of a mixing part and a discharging part. In the first stage, the non-intermeshing screw feeding section and the mixing rotor section are manufactured as a whole, and the materials are continuously fed and mixed, and discharged to the second stage through the discharge valve with adjustable opening at the end. The opening of the valve controls the discharge rate and creates a second-order fullness, builds up pressure, and changes the mixing intensity in the mixing section. The second stage can be a screw extruder, which adopts a screw structure suitable for adding molten materials, and is transported to the head by the screw for granulation or molding. The cavity structure of the head depends on the shape of the exported product. In order to increase the outlet discharge pressure, a gear pump can also be connected in front of the machine head.

The rotor mixing section of the present invention can adopt various high-efficiency mixing rotor structures such as cam-shaped, S-shaped or square rotors. When the three-rotor kneader is running, the material is added to the feeding port, and is conveyed to the kneading rotor section by the screw for repeated mixing and masticating. Since there are three rotors, the strong stretching zone and kneading zone between the rotors are multiplied, so the mixing effect and output can be significantly improved, and it has the effect of energy saving and emission reduction.

Description of drawings

Figure 1 is a schematic diagram of the structure of a three-rotor continuous mixing unit with rotors arranged in a straight line

1-motor, 2-reduction and distribution box, 3-barrel, 4-feeding device, 5-heating device, 6-rotor,

7-rotor cooling device, 8-motor, 9-gearbox, 10-barrel, 11-heating device, 12-screw,

13-machine head, 14-discharging valve, 15-connecting cylinder.

Figure 2 is a schematic diagram of the arrangement of three rotors

Figure 3 is a cross-sectional schematic diagram of a cam shape in the rotor mixing section

Figure 4 is a cross-sectional schematic diagram of an S-shaped rotor used in the rotor mixing section

Figure 5 is a cross-sectional schematic diagram of a quadrilateral rotor used in the rotor mixing section

specific implementation plan

This implementation case is a two-stage three-rotor continuous mixing unit. The centerlines of the three rotors are arranged in parallel in a plane, and the lines perpendicular to the plane are projected to form a straight line, which is an in-line arrangement.

The three-rotor continuous mixing unit with rotors arranged in a line can be composed of a three-rotor continuous mixer connected with a screw extruder, as shown in Figure 1. The mixing part mainly includes: motor 1, deceleration and distribution box 2, barrel 3, feeding device 4, heating device 5, rotor 6, and rotor cooling device 7. The screw extrusion part includes: a motor 8, a reduction box 9, a barrel 10, a heating device 11, a screw 12, and a nose die 13. The mixing part and the screw extruding part are connected by a cylinder 15, in which a discharge valve 14 with an adjustable opening is provided. Motor 1, deceleration and distribution box 2 form the transmission device of the equipment.

The working principle of the continuous mixing unit is: the motor 1 drives the input shaft of the reduction box to rotate, and the torque and speed distribution in the reduction box 2 drives the three rotors 6 to rotate through the three output shafts. The three rotors 6 rely on the end cooling system to regulate the internal temperature. The rotor has a non-meshing screw conveying section and a rotor-type mixing section, and is installed in the barrel 3, and the barrel adjusts the external temperature under the action of the heating device 5 . The material is fed into the barrel 3 through the feeding device 4, and conveyed to the mixing rotor section through the screw. The material is plasticized and mixed depending on the heat introduced from the barrel, the shearing, stretching and extrusion kneading of the rotor. The fully mixed material enters the screw extrusion part through the discharge valve 14 and the connecting cylinder 15, and is extruded through the machine head 13 under the action of screw conveying to carry out granulation or molding. In order to further increase the pressure, a melt pump can also be connected in front of the machine head.

The three rotor mixing sections are non-meshing, so they can be at the same speed or differential speed, and the rotation directions of the three rotors can be combined in different ways. For this reason, an integrated reduction and distribution box can be used, or a separate reduction box and distribution box can be used to realize the combination of rotor motion. The mixing rotor section can make full use of various typical mixing rotor structures, such as the cam shape shown in Figure 2, the S shape shown in Figure 3, and the square rotor type shown in Figure 4.

Since there are three rotors, the strong stretching zone, strong shearing zone and strong extrusion zone between the rotors are doubled, and the exchange of materials between the rotors is more frequent, so that the plasticizing, homogenizing and shearing times of the materials in the screw become Doubling, effectively improving the plasticizing, melting and dispersing performance of the equipment, shortening the processing time, and having the characteristics of energy saving and emission reduction.

Claims (2)

1. the triple-spool continuous mixing unit of rotor yi word pattern arrangement mainly partly is made up of mixing part and discharge, can adopt single-order or two rank form; Wherein mixing part mainly is made up of feeding device, machine barrel, rotor, heating-cooling device and transmission device, it is characterized in that: mixing rotor has three, three rotor centerline are in a plane and be arranged in parallel, and are yi word pattern at vertical this plane projection line and arrange.

2. the triple-spool continuous mixing unit that rotor yi word pattern according to claim 1 is arranged, it is characterized in that: have feeding section and mixing section on the mixing rotor, feeding section adopts screw conveying structure, and mixing rotor section adopts efficient mixing rotor structures such as cam-shaped, S shape and tetragonous rotor type.

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