CN106346734B - A kind of extruder and its extrusion process and system - Google Patents

Abstract

The invention discloses an extruder, comprising a feeding device, a conveying device and a discharging device. The feeding device includes a feeding hopper and a mixing chamber, and the conveying device at least includes two barrel groups, and each barrel group is divided into two groups. There are more than one group of material conveying mechanisms in each barrel group, each barrel group is connected with the mixing chamber of the feeding device, and each barrel group has a feedback channel that communicates with each other, the feedback channel makes each barrel A circulating material flow channel can be formed between the groups and between each barrel group and the mixing chamber. Feedback and circulation, intermittent circulation and parallel and co-directional extrusion processes can be formed in the present invention; the extruders used according to different processes can constitute different types of material continuous extrusion systems.

Description

An extruder and its extrusion process and system

technical field

The present invention relates to the relevant technical field of applying screw extruder to process materials, such as material mixing, pulverizing, heating, reacting and molding in industries such as rubber, plastic, food, building materials, fuel, etc., especially applying screw extruder to process rubber and plastics Field, specifically an extruder and its extrusion process and system.

Background technique

The screw extruder has the characteristics of continuous mixing, dispersing, crushing, conveying and extrusion, especially the single screw extruder has the characteristics of simple structure, low cost and easy maintenance, and is widely used in the fields of rubber and plastics. However, the shearing and pulling force of the single-screw extruder on the material is very limited, and it is difficult to complete the processing requirements of the material within the limited length of the barrel and within a short passing time. If the length of the screw and barrel is increased, although the processing time of the material can be prolonged, it is difficult to ensure high straightness and stability in the processing, installation and operation of the excessively long screw, and it is difficult to ensure The gap between the screw and the barrel is very small, and the increase of the gap will greatly reduce the shear strength and production capacity of the material. Function failed.

Multiple screw rotations in one barrel can improve the processing of materials within a limited length, such as twin screw extruders, triple screw extruders, planetary (ring) screw extruders with more screws in combination with single screw extruders A screw extruder of similar length and time can double the processing capacity of the material. Increasing the diameter of the screw and barrel can also significantly improve the processing capacity of the material. For example, a conical twin-screw extruder can increase the residence time and force of the material in the barrel. In order to fulfill the processing requirements of the material within the limited screw and barrel length and limited pass time, the configuration of the screw flight is decisive. Therefore, various types of screw extruders pay great attention to the research of the screw itself, improve the various processing capabilities of the screw, and form various complex configurations and unit combinations that strengthen shearing, kneading, stretching, and conveying. However, in some applications, a powerful screw cannot solve the problems caused by processing materials with an extruder, and the main factors causing these problems are:

1. At present, all screw extruders can only extrude forward, and the materials along the screw axis cannot be mixed with each other.

2. When the screw configuration, screw and barrel diameter/length are constant, the force and action time of the material in the extruder are restricted by the screw speed, head resistance, extrusion flow, and heat dissipation conditions. These two characteristics make it difficult for the current screw extruder to process some materials to meet the process and performance requirements, especially the material processing that needs to control the time to meet the process performance requirements. In this case, it is not possible to complete the processing requirements of the material in a short time just by increasing the force on the material, but a certain processing time must be guaranteed. Take the processing of tire rubber as an example, such as:

1. The mixing of silica and rubber needs to add a silane coupling agent. The silane coupling agent first chemically reacts with the surface of silica, and can be fully mixed with the rubber after coupling to enhance the rubber effect. This process does not depend on the force of the screw on the material, but mainly depends on the temperature and reaction time, which ensures that the material has a certain residence time in the barrel.

②. The composition of the rubber in each part of the tire is different, the Mooney viscosity of the rubber raw material varies with the origin and batch, and the extrusion volume also varies with the production requirements. These changes will change the capacity and mixing effect of the extruder. However, the force and action time of the existing screw extruder on the material are restricted by the screw speed and extrusion flow, and the screw speed, extrusion flow and residence time cannot be independently adjusted. For example, if you want to increase the mixing intensity, you need to increase the screw speed, but the residence time of the material is shortened, and the extrusion flow rate also increases; if you want to prolong the residence time, you need to reduce the screw speed, but the shear mixing of the material by the screw The smelting intensity decreases, and the extrusion flow also decreases. In either case, the mixing effect of the material and the stability of the extrusion flow cannot be guaranteed at the same time.

③, can not make the material before and after mixing evenly. This is because the thread of the rotating screw can only cause the material to move in the axial direction, and the materials entering the screw groove are arranged in the order of entry time to rotate and move forward, and the front and rear materials, especially the solid materials, are difficult to mix with each other. If the composition of the material before and after is different, the composition of the extruded material will not be uniform. The positive displacement direction of the screw of the existing screw extruder is all towards one direction, that is, the direction of the material outlet. The average composition of the material is basically the average composition of the material when it enters the barrel. The uniformity of the distribution of the material components from the hopper into the barrel has a decisive influence on the uniformity of the extruded material. At present, when the tire rubber is processed by the extruder, it is difficult to ensure the uniformity of the distribution of each component when entering the barrel. The main reasons are:

(a) The geometric dimensions of rubber and other additives are very different. Since rubber is elastic and ductile solid at room temperature, it is difficult to be broken into powder with small particle size. Even if it is pre-made into powder or fine particle, it will re-integrate into a block under the action of external force and its own viscous-flow properties. Therefore, the extruder is generally fed with larger rubber blocks, and most of the additives mixed with the rubber are in powder form, such as carbon black, white carbon black, vulcanizing agent, anti-aging agent, etc. When they are initially mixed in the hopper according to the formula amount, they are easy to concentrate on the surface and gap of the local rubber block, and it is difficult to achieve uniform distribution in the simple and short-term stirring and mixing.

(b), the phases are different. Some additives are liquid, such as aromatic oil, coupling agent, etc. When they are initially mixed in the hopper according to the formula, they will flow to the bottom of the hopper and aggregate, and it is impossible to achieve uniform distribution in simple, short-term, stirring and mixing.

(c), the amount and volume are very different. There are many components in the tire rubber formula with very small amounts, such as vulcanizing agents, accelerators, antioxidants, etc., the amount is only about 1% of the rubber, but it has an important impact on the performance of the tire. When the rubber particles are mixed for a short time, it is difficult to achieve a uniform distribution.

(d), cold feeding has poor pre-mixing effect on the material in the hopper. For materials with different phases to be uniformly mixed, new interfaces must be continuously generated under stirring. However, at present, the screw extruder mainly uses cold feeding for rubber processing. Even if the cold hard block rubber is stirred in the feeding hopper, it is difficult to form a new phase interface, and it is difficult to achieve uniform distribution when mixed with powdery and liquid materials.

(e) The material in the hopper is subject to less stirring force, less force direction dimension and shorter action time. The material needs to be uniformly distributed in a relatively short period of time in the mixing hopper, and the material must be subjected to strong, multi-dimensional forces, and has a long residence, stirring and mixing time. However, in the feeding hopper of the current screw extruder, the material can only rotate radially and move in the axial extrusion direction under the movement of the screw, and the material entering the screw groove will only move forward and enter the barrel. Short residence time in the hopper and lack of front and rear mixing forces.

(f), the flow of material into the barrel is unstable. The larger solid material in the feeding hopper has a large gap, and the material entering the screw groove contains air, so that the groove cannot be fully filled. The high temperature during the mixing process causes the vapor of volatile substances to also generate bubbles. These bubbles move along the screw shaft together with the material, and the effect of radial shearing and mixing of the material between the screw and the inner wall of the barrel will be greatly reduced. The number and size of these bubbles generally vary randomly, so the material mixed by the screw also has inhomogeneity in the radial direction.

The above main factors cause the uneven distribution of the material composition from the hopper into the barrel. When the material does not achieve a relatively uniform distribution in the feeding hopper, most of the materials will not have the opportunity to mix with the materials before and after entering the barrel, resulting in the unevenness of the components along the screw axis or the unevenness with time. sex. Even if the plasticizing and mixing functions of the screw are strengthened, the uniformity can only be improved within a narrow range in the radial or axial direction of the screw, and the uniformity of material mixing cannot be enhanced for a long time and long distance. Since the screw can not mix the materials back and forth, the unevenness of the material in the feeding inner bucket when it enters the barrel determines the unevenness of the mixed material. Therefore, the distribution uniformity of the material in the hopper into the barrel is one of the most important factors affecting the uniformity of the material extruded from the existing screw extruder.

To sum up, the main problems of the existing screw extruder as a continuous mixing extrusion equipment are:

1. The non-uniformity of the feed and the small mixing force and dimension of the force in the feeding hopper result in few new interfaces generated by the mixing, and the short mixing time causes the uneven distribution of the material entering the barrel.

2. The materials entering the barrel cannot be mixed with each other back and forth under the rotation of the screw.

3. The mixing intensity, mixing time and extrusion output all depend on the screw speed. Under the premise of keeping the extrusion output stable, the mixing intensity or mixing time cannot be independently controlled, resulting in the inability to increase the mixing intensity by increasing the mixing intensity. Or prolong the mixing time to improve the mixing uniformity of the material.

Therefore, it is difficult for the existing screw extruder and conventional mixing process to meet the requirements of highly uniform mixing, dispersion and plasticization.

In order to improve the mixing and dispersion uniformity of the existing screw extruder, the geometric dimensions of each component of the raw material should be similar. The feeding hopper of the machine can improve the uniformity of each component of the extruded material. However, the preparation, transportation and storage of powder rubber are very troublesome, and it is easy to self-adhere into a block under the elevated ambient temperature and external pressure, and the powder is very unstable, especially for natural rubber. In addition, the premix dispersion process of the components is a batch process and does not eliminate the inhomogeneity that exists between different mixing batches.

At present, the most feasible and reliable process to improve the mixing and dispersion uniformity of each component of tire rubber and meet the requirements of rubber plasticization is to use an internal mixer or an open mixer to mix rubber. This kind of process does not have strict requirements on the physical and geometric state of each component, and the feeding sequence and rubber mixing time will not affect the final material inhomogeneity as long as the process requirements are met. However, the rubber mixing process of an internal mixer or an open mixer is an intermittent rubber mixing process, and a single device cannot meet the requirements of continuous processing. To achieve continuous processing, multiple sets and multiple devices must work together and have a complex control process. And with the rapid growth of tire production and the continuous improvement of production efficiency, many other problems have arisen. For example, the production capacity of the internal mixer has been continuously improved, and the amount of mixed materials in a single batch has become larger and larger, resulting in huge power consumption, large calorific value and concentrated time, the cooling area per unit volume of material decreases, and the temperature of the material rises. The problem of fast mixing time and shortening of mixing time; the mixing interface of the open mill is only limited to the tangent surface of the two drums, the production efficiency is very low, and the open work pollutes the environment; the quality difference of different batches of mixing and the multiple storage and transportation of materials problems; equipment investment and large land occupation.

SUMMARY OF THE INVENTION

The invention application proposed by the applicant mainly solves the problems existing in the prior art:

1. Solve the problem that the screw speed, residence time and extrusion flow of the existing screw extruder cannot be independently adjusted in a large range according to the material and process requirements, and the problem that the front and rear materials cannot be mixed.

2. Improve the problem of uneven mixing of the various components in the feeding hopper of the existing screw extruder before entering the barrel and the problem that larger pieces of material do not enter the barrel smoothly.

3. Improve the uniformity of materials mixed by the existing screw extruder.

4. Solve the problem that the existing rubber mixing equipment cannot be continuously mixed and extruded continuously, and improve the problems of low production efficiency, high power consumption, poor heat dissipation, rapid temperature rise and uneven mixing batches.

5. Reduce energy consumption and water consumption.

An extruder that can solve the above technical problems, its technical scheme mainly includes a feeding device, a conveying device, and a discharging device, and the feeding device is provided with a feeding hopper and a mixing chamber. The difference is that the conveying device includes at least two Barrel groups, each barrel group is arranged in parallel, each barrel group has more than one set of material conveying mechanisms, each barrel group is communicated with the mixing chamber of the feeding device, and each barrel group has interconnected feedback channels , the feedback channel can form a circulating material flow channel between each barrel group and between each barrel group and the mixing chamber.

The barrel group can be composed of one barrel or several barrels connected in series.

The material conveying mechanism includes a screw or several screws, a shearing dispersing unit, and/or a combination of the screw and the shearing and dispersing unit; the screws can rotate in cooperation with each other or independently or in the same direction or in the opposite direction.

The material conveying mechanism includes a screw or a combination of several screws, and the screws can rotate in coordination with each other or independently or rotate in the same direction or in the opposite direction.

The barrels are barrels of different diameters or barrels of equal diameter, and the diameters and lengths of the corresponding screws are correspondingly equal or unequal.

The ends of the screws are supported by connection with bearings, bearings with barrel and/or with frame.

The feedback channel is provided with a mechanism for controlling the size and opening and closing of the material flow section, for example, a feedback channel valve for controlling the material flow rate can be used.

The discharging device is one of a discharging control mechanism, a shearing and dispersing unit, a filtering unit, a constant flow control unit, and a die of a die or a combination of two or more thereof.

A structure of the shearing and dispersing unit includes a group of more than one ring and disc, the outer edge of the ring is connected and fixed with the inner wall of the barrel, and the annular hole in the middle allows the shaft of the screw and the material to pass through; The center of the disc is connected and fixed with the shaft of the screw, the outer edge of the disc allows the material to pass through, and the gap between each ring and the disc is fixed and/or adjustable. Or the surface of the disc is smooth, or has grooves, or has convex edges.

The discharge control mechanism is a mechanism for controlling the size and opening and closing of the discharge flow section, such as a discharge valve.

The filter unit is a porous material with a network structure, which only allows materials smaller than the pore size to pass through.

The constant current control unit is a melt gear pump, or a screw pump, or a turbine worm mechanism.

The die of the die is one of the flow channel, the pre-die, the die of the material, or a combination thereof.

There are at least one or more than two discharging devices, which are arranged at the end of the barrel or near the end, and/or at any position outside the barrel.

The parallel arrangement of the two barrel groups is: horizontal arrangement with each other, vertical arrangement up and down, or inclined arrangement up and down.

The inner cavity of the barrel may be smooth, or have grooves, or have pins extending into the inner cavity of the barrel.

The mixing chamber contains at least two screws that pass through the bottom of the mixing chamber and are connected to the driving mechanism, wherein the screws can be meshed with each other or not.

A feedback and cyclic extrusion process of the above-mentioned extruder is adopted, and the extrusion method is as follows: the material is put into the feeding hopper of the feeding device, and after the material is initially mixed in the mixing chamber of the feeding device by the conveying device, it is transported into one of the materials containing For the barrel of the forward extrusion conveying device, by adjusting the positive displacement constant current control unit, a part of the material is discharged from the discharge port of the discharge device in proportion, and the other part of the material is transported into the feedback channel between the two barrels. The barrel containing the conveying device for reverse extrusion returns to the mixing chamber of the feeding device, merges with the new material added from the feeding hopper, and is conveyed and mixed through the mixing chamber of the feeding device into the machine containing the conveying device for forward extrusion. In the barrel, this cycle forms a continuous feedback loop extrusion process.

Another intermittent cycle extrusion process using the above-mentioned extruder, the extrusion method is as follows: the discharge port of the discharge device is closed first, the material is continuously fed from the feeding hopper until all the barrel groups are filled, and the material passes through the material conveying mechanism. The interconnected barrel group, feedback channel and feeding device circulate in circulation. After a certain period of continuous circulation, the discharge port of the discharge device is opened, and the material is discharged from the discharge port.

Another parallel and co-directional extrusion process using the above extruder, the extrusion method is as follows: the material is input from the feeding hopper, and enters into the two barrel groups simultaneously through the material conveying mechanism, and simultaneously goes to the direction of the discharging device. Conveying is carried out, and the material is discharged from the discharge port.

A material continuous extrusion system formed by the above extruder and its corresponding extrusion process is a continuous production line with two or more extruders connected in series or in parallel to form a continuous production line with component time and multi-stage feeding.

Beneficial effects of the present invention (take the mixing of rubber as an example):

1. Through the circulation of part or all of the material in two or more barrels, the average residence time of the material in the barrel can be controlled by controlling the feedback ratio.

2. Increasing the rotation speed of the screw can increase the circulation flow of the material in the barrel, and enhance the plasticization and dispersion strength of the screw and the barrel to the material, but under the control of a constant flow control unit such as a melt gear pump, the material will not increase. As long as the positive displacement flow of the material generated by the rotation speed of the screw is greater than the flow rate discharged by the constant flow control unit, the rotation speed of the screw can be independently adjusted relative to the discharge volume, which enhances the extruder for materials with different mixing requirements and production capacity requirements. adaptability of the process.

3. The feedback material is continuously mixed with the newly added material in the feeding hopper, so that the material added at different times can be mixed repeatedly for many times, which can eliminate the uneven distribution of the components of the material added before and after and because the material enters the screw groove of the barrel before and after. Material unevenness caused by unstable material flow.

4. The feedback material transfers the extrusion pressure of the screw to the feeding port in time. The first and last ends of the feedback loop system are connected to the atmosphere, and the low pressure in the barrel is maintained under the high-speed rotation of the screw. Low pressure reduces barrel and screw wear, frictional energy consumption, and temperature rise caused by frictional heat generation.

5. Compared with the existing single-screw extruder of the same length and the same diameter, the twin-screw twin-barrel shortens the length of a single screw, improves the stability of the screw during high-speed rotation and its tightness with the barrel , improve the mixing performance and production capacity.

6. The discharge port of the barrel material is set on the side of the cylindrical barrel, so that both ends of the screw in the barrel can be fixed with the barrel through bearings, which improves the stability of the high-speed rotation of the screw and its tightness with the barrel , improve the mixing performance and production capacity.

7. The feedback hot material heats and softens the cold material newly added to the hopper. Under the stirring and mixing action of the relatively conveyed twin-screw shearing, tearing and rotating, it is easier to generate a new mixing interface and speed up the process. The materials are evenly mixed in the hopper.

8. The twin screws close to each other in the feeding hopper form a strong bite to the material, which enhances the ability of the screw to press cold, hard and larger materials into the screw groove.

9. The screw rotation of feedback extrusion enhances the shearing and tearing force on the material in the feeding hopper, enhances the horizontal and vertical rotation force of the material in the feeding hopper, prolongs the residence and mixing time of the material in the feeding hopper, and improves the The mixing uniformity of the material in the hopper is improved.

10. The newly added cold material is preheated by the feedback hot material, which shortens the solid melting time and length in the barrel, which is equivalent to increasing the effective mixing length of the screw in the barrel and improving the screw mixing. The ability to improve the uniformity of material mixing.

11. The hot material extruded by feedback heats the cold material in the feeding hopper, which is equivalent to the high temperature hot material in the barrel being led out of the barrel for cooling. The feeding hopper acts as a cooler, which can reduce the temperature of the material in the barrel. It can also reduce or save the heating of the cold material, and the pressure in the barrel is reduced, which reduces the total energy input and frictional heat generation, and the cooling water required for cooling is correspondingly reduced, which can significantly save energy and water.

12. Compared with the existing screw unidirectional mixing extruder, the feedback material enables the successively added materials to be mixed with each other, which improves the uniformity of the material, prolongs the residence time of the material, and meets the processing requirements controlled by time. The change of screw speed has no effect on the flow rate of the discharge port, so the speed of the screw can be changed according to the characteristics of the material and the temperature rise, which meets the processing requirements of dispersion control or temperature control.

13. Compared with the existing batch mixing equipment, the continuous feedback and circulation process of materials in multiple barrels has a higher similarity with the circulation in one mixing space, so the uniformity of their mixing materials The difference is small, but continuous mixing reduces batch non-uniformity in batch mixing. Under the same production capacity, the volume of mixing materials required per unit time is greatly reduced, so the electrical power required by the equipment is greatly reduced , the heat generated by the work-heat effect of mixing per unit time is greatly reduced. The barrel material filling rate of the screw extruder is high, the material heat dissipation area per unit volume is large, and the cooling water cooling efficiency is high, which makes the mixing temperature rise relatively slow and the mixing time is prolonged.

14. The feedback material makes the material have different residence times in the barrel, so that the molecular weight of the mixed rubber has the characteristics of wide distribution, which improves the processing and molding performance and the comprehensive mechanical properties of the product.

15. For the multi-stage mixing process that needs to add materials of different components at different times for mixing, a continuous mixing production line can be formed by using the corresponding feedback extruders with the same number, similar models and different parameters. Short, compact, small footprint, easy to control.

16. With the extruder provided by the present invention, the extrudable material is one or more objects or mixtures thereof in liquid, powder and/or solid structures, and is particularly suitable for powders and/or mixtures with different particle sizes. Mixing and extrusion of bulk materials.

Description of drawings

FIG. 1 is a schematic structural diagram of an embodiment of the extruder of the present invention.

FIG. 2 is a flow chart of the forward extrusion of one screw and the reverse extrusion of the other screw in the embodiment of FIG. 1 .

FIG. 3 is a flow chart of simultaneous forward extrusion of twin screws in the embodiment of FIG. 1 .

FIG. 4 is a schematic view of the embodiment of FIG. 1 , where the feedback channel is arranged in the middle of the main barrel.

FIG. 5( a ) is a schematic diagram of the horizontal arrangement of the main and auxiliary barrels in the embodiment of FIG. 1 .

Fig. 5(b) is a schematic diagram of the vertical arrangement of the main and auxiliary barrels in the embodiment of Fig. 1 .

Fig. 5(c) is a schematic diagram of a scheme in which the main and auxiliary barrels are arranged obliquely in the embodiment of Fig. 1 .

Fig. 5(d) is a schematic diagram of another scheme in which the main and auxiliary barrels are arranged obliquely in the embodiment of Fig. 1 .

FIG. 6 is a working mode diagram of the main and auxiliary barrels extruding in the same direction in the embodiment of FIG. 1 .

FIG. 7 is a working mode diagram of the embodiment of FIG. 1 , when the feedback channel is closed and the main barrel is extruded alone.

Fig. 8 is a working mode diagram of the main barrel and the auxiliary barrel in the embodiment of Fig. 1, with the discharge port of the main barrel closed, the feedback channel opened, and the material circulating in the main barrel and the auxiliary barrel.

FIG. 9 is a working mode diagram of the embodiment of FIG. 1 , when the feedback channel is opened, and part of the material of the main barrel is fed back to the auxiliary barrel.

FIG. 10 is a structural diagram of the bearing installation at the tail of the auxiliary screw in the embodiment of FIG. 1 .

11 is a structural diagram of the bearing installation at the tail of the main and auxiliary screws in the embodiment of FIG. 1 , wherein the discharge port of the main barrel is arranged laterally.

FIG. 12 is a working mode diagram of the main and auxiliary barrels in FIG. 11 .

FIG. 13 is a working mode diagram of the embodiment of FIG. 1 , with the feedback channel open and the discharge port laterally disposed on the auxiliary barrel.

Figure 14 is a material process flow diagram of an extruder as a continuous compounding and extrusion device.

FIG. 15( a ) is a working mode diagram of the feedback of some materials through the auxiliary barrel in the embodiment of FIG. 1 .

Fig. 15(b) is a schematic diagram of the feeding of the main and auxiliary screws in Fig. 15(a).

FIG. 16 is a schematic structural diagram of a mixing unit in the embodiment of FIG. 1 .

Figure 17 is a flow diagram of a material extrusion process with feedback using an extruder as a continuous compounding and extrusion device.

Figure 18 is a flow diagram of a feedback-free material extrusion process with an extruder as a continuous compounding and extrusion device.

Fig. 19 is a schematic diagram of the extrusion system according to the embodiment of Fig. 1 which is arranged in series on the left, the middle and the right.

Fig. 20 is a schematic diagram of the extrusion system according to the embodiment of Fig. 1, which is arranged in parallel with the upper left, the upper right, and the upper and lower series in series.

Figure 21 shows the feedback ratio x of the material at point B under different R conditions in the working mode of Figure 9 .

Fig. 22 shows the extrusion ratio xi at point B of the new material continuously added at a certain time in Fig. 21 after ⁱ times of feedback loop and continuous extrusion.

FIG. 23 shows the relationship between the number of cycles i and the cumulative distribution ratio in FIG. 22 .

Fig. 24 shows the distribution rate of materials at point B for different cycle times or residence times in Fig. 22 .

Fig. 25 shows the relationship between the feedback/extrusion ratio R and the average dwell time in the working mode of Fig. 9 .

FIG. 26 shows the relationship between the number of cycles i and the cumulative distribution ratio in FIG. 25 .

FIG. 27 shows the relationship between the number of cycles and the average residence time in FIG. 25 .

Drawing number identification: 1. Machine base; 2. Electric motor; 3. Double output reducer; 4. Feeding device; 4a, Feeding hopper; 4b, Mixing chamber; 5. Main barrel; 6. Auxiliary barrel; ; 8, auxiliary screw; 9, pin; 10, discharge device; 10a, discharge valve; 10b, shearing and dispersing unit; 10c, melt gear pump; 10d, die of die; 11, exhaust port; 12 , feedback channel; 12a, feedback channel valve; 13, bearing; 14, extruder.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

An extruder of the present invention includes a feeding device 4, a conveying device, a discharging device 10, a driving device, a cooling device and a control device, the feeding device 4 includes a feeding hopper 4a and a mixing chamber 4b, and the conveying device at least includes Two barrel groups, two barrel groups are arranged in parallel, each barrel group has more than one set of material conveying mechanisms, each barrel group is communicated with the mixing chamber 4b of the feeding device 4, and its main feature is that each barrel group is There is a feedback channel 12 communicating with each other, and the feedback channel 12 can form a circulating material flow channel between each barrel group and between each barrel group and the mixing chamber 4b, so that the material in one barrel group can flow freely. Part or all of the material can flow into another barrel group, and finally part or all of the material flows from the mixing chamber 4b through each barrel and then returns to the mixing chamber 4b, where it is mixed with the newly added material to form a continuous feedback or cycle; the The simplest form of the system is an annular circulation system composed of two barrels and their internal screws. The screws inside the two barrels are connected to the driving device through the bottom of the mixing chamber 4b, and the two screws can be meshed with each other or not; the The driving device includes a motor 2 and a double-output reducer 3 driven by the motor 2. The double-output reducer 3 has at least one output shaft with forward and reverse rotation functions, as shown in Figure 1, and the process flow is shown in Figures 2 and 2. shown in Figure 3.

Further description is that there are two parallel barrels (5, 6 in Figure 1), and the two barrels have at least two channels that communicate with each other (4b, 12 in Figure 1), and both barrels have Or one of the barrels has at least one feeding device (4 in Figure 1) and at least one discharging device (10 in Figure 1), and the discharging device 10 can be a flow control unit (Figure 1 10a, 10c ), a combination of shear mixing unit (10b in Figure 1) and die (10d in Figure 1). Each barrel has at least one set of material conveying mechanisms, such as at least one screw (7 and 8 in Figure 1). The screws in the two barrels can share the power and speed of a set of driving devices, or they can have independent power And the speed regulating mechanism; the screws in the two barrels can rotate independently or in cooperation with each other, can rotate in the same direction or in the opposite direction, and can extrude the materials in the barrels in the same direction or relative to each other. The inner diameters of the two barrels and the screw diameters therein can be the same or one larger and the other smaller. In general, when the material flow of the two barrels is different, one of the inner diameters of the two barrels and the diameter of the screw in them is larger, and the other is smaller, so as to facilitate adjustment and control. The larger diameter barrel is called the main barrel (5 in Figure 1), the conveying mechanism in the main barrel 5 is called the main barrel conveying mechanism (the main screw 7 in Figure 1), and the smaller diameter barrel is the auxiliary barrel (6 in FIG. 1 ), the conveying mechanism in the auxiliary barrel 6 is called the auxiliary barrel conveying mechanism (the auxiliary screw 8 in FIG. 1 ). The main screw 7 only extrudes the material forward and forward, while the auxiliary screw 8 can rotate forward or reverse, and can extrude the material toward the discharging device 10 or the feeding device 4 direction. One of the two communication ports of the two barrels communicates at the ends of the two barrels and merges with the mixing chamber (4b in FIG. 1 ) in the feeding device 4 into one port. The arrangement of the other communication port, when the lengths of the two barrels are similar, can be arranged at a position where the two ends of the two barrels are far apart (as shown in the feedback channel 12 in Figure 1); when the lengths of the two barrels are quite different, It can be arranged at the position of the middle of the longer barrel (eg, the main barrel 5 ) and the end of the shorter barrel (eg, the secondary barrel 6 ) opposite (as shown in FIG. 4 ). The relative positions of the axes of the two parallel barrels can be horizontal (as shown in Figure 5a), vertical up and down (as shown in Figure 5b), and inclined up and down (as shown in Figures 5c and 5d).

The cooling device is one of water cooling, air cooling, or oil cooling, or a combination thereof, and the cooling device is arranged at least on one of the feeding device, the barrel group, the conveying device, and the discharging device.

The control device includes a driving device, a feeding device, a conveying device, a feedback channel, a discharging device, and a control method and mechanism for a cooling system.

The extruder can have four working modes:

(1) When the two screws are extruded in the same direction, it is equivalent to a large screw extruder with a long length and a large capacity (as shown in Figure 6).

(2), when only the screw in one barrel (such as the main barrel 5) is extruded and the screw in the other barrel stops working and closes the feedback channel 12 of the two barrels (implemented through the feedback channel valve 12a), it can be It becomes a small screw extruder with shorter length and smaller capacity (as shown in Figure 7).

(3) When the discharge port is closed and the material is not discharged to the outside of the barrel, the screw of the main barrel 5 is extruded forward, and the screw in the auxiliary barrel 6 is reversely extruded, so that all the materials extruded from the main barrel 5 are reversed. Returning to the feeding hopper 4a of the main barrel 5, all the materials are circulated in the two barrels, which can become a batch mixing equipment (as shown in Figure 8).

(4) When the screw of the main barrel 5 is extruded in the forward direction, the screw in the auxiliary barrel 6 is extruded in the reverse direction, and part of the material in the main barrel is fed back to the feeding hopper 4a of the main barrel 5, and another part of the material is discharged from the barrel, Can become a continuous mixing and extrusion equipment (as shown in Figure 9).

The principles of the above three working modes (1), (2) and (3) are obvious. The following description mode (4) can solve the three main problems of the existing screw extruder as a continuous mixing extrusion equipment. method.

①. Improve the mutual mixing degree of materials with different dispersion uniformity added at different times. Obviously, feedback extrusion enables the intermixing of materials with different homogeneities added at different times. By controlling the proportion of extruded and feedback materials, and controlling the speed of the screw to control the feedback flow, the materials with different uniformity added at different times are mixed before and after dozens of times to improve the uniformity. Fig. 14 is the material process flow chart of mode (4), V ₁ (m ³ /s) is the volume velocity of the material discharged from the constant flow control unit, and also the volume velocity of the feeding material, which is determined by the output capacity required by the production, and is generally a fixed value ; V ₂ (m ³ /s) is the volume velocity of the feedback extrusion of the auxiliary screw 8; (V ₁ +V ₂ ) is the volume velocity of the forward extrusion of the main screw 7; feedback/extrusion ratio R=V ₂ /V ₁ . V ₂ is determined by the rotation speed of the two screws according to the requirements of material dispersion and plasticization. The feedback ratio x=R/(1+R) of the material at point B under different R is shown in the coordinate diagram of Fig. 21 .

After the new material added continuously at a certain time has undergone i times of feedback loops and continuous extrusion, the extrusion ratio ^xi at point B is shown in the coordinate diagrams of Figure 22 and Figure 23.

The distribution rate of materials at point B with different cycle times or residence time is shown in the graph of Figure 24.

②. Under the control of a constant flow unit at the discharge port, the speed of the screw is increased, and the increased flow is fed back to the feeding hopper 4a without affecting the stability of the extrusion discharge. In this way the mixing intensity can be varied independently of the extrusion capacity. For simple dispersion mixing, the kneading time can be shortened by increasing the kneading intensity, or the kneading intensity can be reduced by prolonging the residence time. For dispersion mixing with chemical reaction, the chemical reaction requires a certain time. By increasing the extrusion/feedback ratio R, the average residence time of the material in the barrel can be increased (as shown in the graphs of Figure 25, Figure 26, and Figure 27) .

where t _a is the time for the material to go from A→B→C→D→A in Figure 14, but part of the extrusion capacity will be lost.

3. In the feeding device 4, the two barrels are connected to the bottom of the feeding hopper 4a, the outer diameter of the screw thread is increased, the screw groove is deepened, and the screw edges of the two screws are close but non-contact, which can adjust the material between them. Generates high occlusal and shearing forces. The hot material fed back from the auxiliary barrel 6 continues to move backward along the screw groove of the auxiliary screw 8 until the end of the screw. Move forward and enter the main barrel 5. Therefore, hot material is wound in the grooves of both screws. When the newly added cold material is in contact with the screw, it will be heated and softened, and the material will be deformed and broken under the action of extrusion, shearing and stretching forces between the two screws and between the screw and the wall of the feeding hopper, resulting in a new interface. , to speed up the mixing and dispersion of different components. The two screws push and rotate in opposite directions, so that the material on the screw rotates vertically and horizontally, which enhances the stirring and mixing intensity of the material and the residence time in the hopper. When the screw grooves to which the two screws rotate are opposite to the screw grooves, the gap between the two screws is the largest, and larger pieces of material can be engaged into the screw grooves; The smallest, which can generate a large shear force on the material; when rotated until the screw edge is opposite to the screw groove, it can bite smaller pieces of material or produce tensile and tearing effects on the larger material in the original screw groove. Therefore, the fed back hot material and the twin screw are pushed horizontally and rotated up and down oppositely, so that the mixing uniformity of the material in the feeding device 4 is improved (as shown in Fig. 15a and Fig. 15b ).

④, save energy and water and improve efficiency. Feed back the material in the barrel from the discharge port to the feed port of the barrel, so that both ends of the entire material circulation system composed of the connected barrels are connected and communicated with the atmosphere. The increase of the screw speed and the acceleration of the material flow rate will not The pressure of the barrel is obviously increased, so the pressure in the barrel is lower, the friction force is reduced, the wear is reduced, the energy consumption is reduced, and the temperature rise is reduced. Feedback of hot material to preheat the newly added cold material can reduce or even eliminate the need for additional heating of the material in the solids compression section of the barrel. The input heating energy is reduced, the heat that needs to be discharged is also reduced, the cooling water is correspondingly reduced, the temperature rise is slower, and the mixing time is prolonged. The newly added cold material is mixed and preheated in the hopper, which shortens the melting time of the solid cold material in the barrel, which is equivalent to prolonging the length of the mixing, dispersing and plasticizing sections of the screw, and improves the mixing of the screw. efficiency. The feedback material is mixed with the cold material in the hopper, which is also equivalent to pulling some of the material with higher temperature in the barrel out of the barrel and directly contacting with the cooling medium for cooling before entering the barrel. At this time, the feeding hopper is equivalent to a cooler. Strengthen the cooling capacity of the hopper, control the temperature of the material in the hopper when it enters the barrel as required, and work with the circulating cooling water system in the barrel and/or screw to control the temperature rise of the material in the barrel. In addition to the cold material added as a cooling medium, an indirect cooling cycle system of water cooling, air cooling and oil cooling can also be added to the hopper, or even a low-boiling evaporative medium can be directly added to directly cool down the temperature of the material in the hopper.

⑤ Compared with batch mixing equipment, the material flows continuously through the equipment, and there is no intermittent time for mixing. Under the same production capacity, the volume of material mixed by the equipment per unit time will be reduced, and the required mixing power will be reduced. , the heat generated will be reduced. Therefore, the power required by the equipment is reduced, and the material between the screw and the barrel is in close contact with the barrel wall, the filling rate is high, the air for adiabatic effect is less, the cooling and heat dissipation conditions are better, and the temperature rise speed is slow. Extend the mixing time.

In order to accurately control the flow of materials fed back to the hopper 4a, accurately control the extrusion flow to the discharge port, and increase the extrusion pressure at the discharge port, the discharge port needs a device for controlling flow and pressure, and a melt gear pump 10c can be used to Control the discharge port flow and pressure (as shown in Figure 1).

From the feedbackable continuous dispersion mixing and extrusion workflow of the present invention (as shown in Figure 2 and Figure 14 ), it can be seen that there will inevitably be a part of the newly added material (1/(1+R)) only after ≤ t _a Time is squeezed out of the discharge port. In order to reduce the impact of this part of the material with short residence time, take the following measures:

1. A filter unit is added before the discharge port and after the feedback channel 12, so that the undispersed coarse materials are not extruded and flow into the feedback process.

2. A set of strong shearing dispersing and mixing units 10b are added at the discharge port to speed up the dispersity of the extruded material. For example, at the top of the main screw 7 and before the discharge port, a set of shear dispersion composed of a ring (equivalent to a flattened barrel with an inner screw) and a disc (equivalent to a flattened screw) is installed. unit (as shown in Figure 1 and Figure 16). The outer edge of the ring is connected and fixed with the barrel, and the annular hole in the middle allows the shaft of the screw and the material to pass through; the center of the disc is connected and fixed with the shaft of the screw, and the circular edge allows the material to pass through. Relative rotation of the ring and disc produces high shear strength. There may be raised spirals on the surfaces of the ring and the wafer, or only one of the surfaces may have raised spirals, which can produce positive displacement and convey in the direction of the discharge port. The gap between the rings and the discs can be adjusted, and the number of rings/discs can be increased or decreased. In this way, the length and time of the passage of the discharged material can be controlled.

3. Increase R to make the proportion of this part of the material in the discharge material smaller.

In order to improve the mixing capacity and production capacity of the extruder of the present invention, and increase the feedback/extrusion ratio R, it is necessary to reduce the clearance between the flight and the barrel and increase the rotational speed of the screw. This requires improved radial stability of screw rotation. Both ends of the screw are fixed on the barrel by bearings 13 to improve the radial stability of rotation. When there are bearings 13 at both ends of the screw to be fixed to the barrel, the extrusion discharge port originally at one end of the barrel must be set on the side of the cylindrical barrel. Both ends of one or two screws can be fixed to the barrel through bearings 13 , as shown in FIGS. 10 and 11 . The material discharge port can be set on the main barrel 5 or on the position of the auxiliary barrel 6, which can increase the average residence time of the extruded material in the barrel (as shown in Figure 11, Figure 12, Figure 13). Show).

The extruder of the present invention can also be able to close the discharge port, temporarily prevent the material from being discharged, and pass the material from the mixing chamber 4b through the main barrel 5, the feedback channel 12, and the auxiliary barrel 6, and return all the material to the mixing chamber 4b. After continuous circulation for a certain period of time, it is discharged from the discharge port, so as to realize the intermittent mixing and dispersing processing of batch materials. The process flow is shown in Figure 17.

The extruder of the present invention can also be conveyed by the positive displacement inside the main barrel 5 and the auxiliary barrel 6, for example, the main screw 7 and the auxiliary screw 8 are extruded in the same direction, and the material is extruded from the mixing chamber 4b into the two barrels at the same time, The material is discharged from the discharging device 10, so that the production capacity of the extruder can be increased with a smaller inner diameter barrel and a smaller screw length-diameter ratio. The process flow is shown in Figure 18.

In order to further illustrate the problem to be solved by the extruder of the present invention, the working mode and application of this type of extruder are further described below through examples.

Example 1: Three-stage serial continuous compounding process (Figure 19), a form of extrusion system.

The rubber formula to be mixed is shown in Table 1, and the final rubber production capacity is 2100kg/h.

The three-stage serial continuous mixing process is to mix all natural rubber, all white carbon black, one-third carbon black, all zinc oxide, and all stearic acid in the first stage for 75s to form a masterbatch I,

In the third stage, the remaining two-thirds of carbon black and other components are mixed with masterbatch 1 for 70s to form masterbatch II, and in the third stage, masterbatch II is mixed with all sulfur and all accelerators for 90s into the final rubber. The continuous mixing and feeding method is as follows.

The first stage of mixing: Raw materials continuously added to the extruder 14 on the left: natural rubber 333.3g/s, carbon black 46.7g/s, silica 50g/s, zinc oxide 20.4g/s, stearic acid 6.6g /s. The average residence time of the kneaded material is 75s, and the control temperature is below 155℃. The melt gear pump 10c continuously extrudes the masterbatch I and is cooled for a certain distance and time, and sent to the second-stage extruder 14 (middle), the extrusion flow rate is 1614kg/h (448.3g/s≈0.374L/s) . The screw parameters in the two barrels of the left extruder 14 are the same: screw length 1650mm, screw diameter 240mm, thread angle 35°, average screw groove depth 25mm, screw width 25mm, and the number of threads 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 7.5s, the material volume in the barrel is about 33.7L, and the motor power is 250kW.

The second stage of mixing: the masterbatch II and the remaining 2/3 of carbon black (the amount of carbon black added is 93.3 g/s)/other components 33.3 g/s are continuously added to the intermediate extruder 14. The average residence and mixing time of the material is 80s, and the control temperature is below 155 °C. The melt gear pump 10c continuously extrudes the masterbatch and delivers it to the third-stage extruder 14 (right) after cooling for a certain distance and time, and the extrusion flow rate is 2070kg/h (575g/s≈0.479L/s). The screw parameters in the two barrels of the middle extruder 2 are the same: the screw length is 1760mm, the screw diameter is 240mm, the thread angle is 35°, the average screw groove depth is 35mm, the screw edge width is 35mm, and the number of threads is 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 8s, the material volume in the barrel is about 46L, and the motor power is 280kW.

The third stage of mixing: the extruder 14 on the right is continuously adding masterbatch, 3.3 g/s of sulfur and 5.0 g/s of accelerator. The average residence time of the kneaded material is 90s, and the temperature is controlled below 100°C. Melt gear pump continuously extrudes 2100kg/h (583.3g/s≈0.486L/s). The screw parameters in the two barrels of the extruder 14 on the right are the same: screw length 2000mm, screw diameter 242mm, thread lift angle 35°, average screw groove depth 35mm, screw width 35mm, and the number of threads 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 9s, the material volume in the barrel is about 52.5L, and the motor power is 300kW.

Start-up operation process steps:

①. First, open the extruder 14 (left side) for one-stage mixing, close the melt gear 10c, and feed according to the formula amount and feeding speed calculated above. The material is continuously heated to the temperature required by the process under the shearing and extrusion friction between the screw and the barrel. When the material fills the two barrels to form a closed cycle, stop feeding. When the cycle time is greater than the average residence time of the section, turn on the melt gear pump 10c, discharge the glue according to the calculated flow, and transport it to the second section after a certain time and distance. Extruder 14 (middle), while starting to continuously feed new material to one stage of extruder 14 (left).

(2) The melt gear pump 10c of the second-stage extruder 14 (middle) is closed, and the first-stage extruder 14 (left) is supplied with glue, and the material is continuously fed according to the calculated formula amount and feeding speed. When the material is full of the two machines After the barrel forms a closed cycle, the feeding is stopped and the discharging of a section of extruder 14 (left side) is stopped at the same time, and the material is continuously heated to the temperature required by the process under shearing and extrusion friction between the screw and the barrel. After the circulation residence time is greater than the average residence time of the section, the melt gear pump 10c is turned on, the glue is discharged according to the calculated flow rate, and the glue supply from the first-stage extruder 14 (left) to the second-stage extruder 14 (middle) is restored at the same time. The rubber material discharged from the second-stage extruder 14 (middle) is cooled and transported to the third-stage extruder 14 (right) after a certain time and distance, and new materials are continuously added at the calculated formula amount and feeding speed.

(3) The three-stage extruder 14 (right side) is turned on to receive the glue from the second-stage extruder 14 (middle), the melt gear pump 10c is closed, and the two-stage extruder is continuously fed according to the calculated formula amount and feeding speed. For the glue supply of the extruder 14 (middle), when the material fills the two barrels to form a closed cycle, the feeding is stopped and the discharge of the first-stage extruder 14 (left) and the second-stage extruder 14 (middle) is stopped at the same time. The material is continuously heated to the temperature required by the process under the shearing and extrusion friction between the screw and the barrel. After the material circulation residence time in the three-stage extruder 14 (right side) is greater than the average residence time of this section, the melt gear pump 10c is turned on, and the glue is discharged from the auxiliary machine downward according to the calculated flow rate, and at the same time, the calculated formula amount and feeding The speed begins to continuously feed new material and simultaneously resume the discharge of the first stage extruder 14 (left) and the second stage extruder 14 (middle). When the materials of the three extruders 14 are continuously connected, the temperature of each section, cooling water flow, feeding speed, screw speed and gear pump speed should be well controlled to maintain the coordination of each section to form continuous and stable production.

Example 2: "Y"-shaped three-stage continuous mixing process (as shown in Figure 20), which is another form of extrusion system.

The rubber formula to be mixed is shown in Table 2, and the final rubber production capacity is 4013kg/h.

The "Y"-shaped three-stage continuous mixing process is to mix one third of natural rubber, all silane coupling agents and all precipitated silica into masterbatch I, and two-thirds of natural rubber is mixed. , All carbon black, zinc oxide, stearic acid, microcrystalline wax and anti-aging agent are mixed into master batch II, and then master batch I, master batch II, sulfur and accelerator are mixed into final rubber. The function of mixing masterbatch I is to silanize the surface of the precipitated silica, and it can be used under high concentration, high temperature and long time mixing.

The chemical reaction is more complete and the dispersion is better, avoiding the problem of over-mixing caused by mixing with all the rubber, improving the production efficiency, reducing the energy consumption of mixing and improving the comprehensive performance of the tire. The continuous mixing and feeding method is as follows.

The first stage of mixing: continuously add one third of the natural rubber 434.3 g/s, silica 260.6 g/s, and silane coupling agent 45.6 g/s to the extruder 14 on the upper left. The average residence time of the kneaded material is 70s, and the temperature is controlled below 160°C. The melt gear pump 10c continuously discharges the masterbatch I at 1297.73kg/h (360.5g/s≈0.316L/s), and is transported to the middle and lower extruder 14 after cooling for a certain distance and time. The screw parameters in the two barrels of the extruder 14 on the upper left are the same: screw length 1290mm, screw diameter 200mm, thread angle 35°, average screw groove depth 32mm, screw width 30mm, and the number of threads 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 7s, the material volume in the barrel is about 26.5L, and the motor power is 250kW.

The second stage of mixing: two-thirds of natural rubber 434.3g/s, carbon black 260.6g/s, zinc oxide + stearic acid + microcrystalline wax 32.6g/s, Anti-aging agent 13.03g/s. The average residence time of the kneaded material is 75s, and the control temperature is below 155℃. The melt gear pump 10c discharges the masterbatch II at 2665.82kg/h (740.5g/s≈0.650L/s), and after a certain distance and time cooling, it is transported to the middle and lower extruder 14. The extruder 14 has two The screw parameters in each barrel are the same: screw length is 1930mm, screw diameter is 242mm, thread angle is 39°, average screw groove depth is 33mm, screw edge width is 32mm, and the number of threads is 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 7.5s, the material volume in the barrel is about 58.5L, and the motor power is 400kW.

Stage 3 mixing: The masterbatch mixed in stage 1 and stage 2 simultaneously supplies rubber to the extruder 14 in the middle and lower part, and simultaneously adds 6.5g/s of sulfur and 7.2g/s of accelerator. The average residence time of the kneaded material is 55s, and the temperature is controlled below 100°C. The melt gear pump 10c discharges the final rubber mixture at 4012.8kg/h (1108.2g/s≈0.978L/s). The screw parameters in the two barrels of the middle and lower extruder 14 are the same: screw length 1630mm, screw diameter 280mm, thread angle 39°, average screw groove depth 36mm, screw width 32mm, and the number of threads 3. The screw speed is 50r/m, the extrusion rate feedback ratio is R=11, the single cycle time is 7.5s, the material volume in the barrel is about 88L, and the motor power is 520kW.

Start-up operation process steps:

①, firstly open the upper left extruder 14 for the first stage mixing and the upper right extruder 14 for the second stage mixing, the melt gear pump 10c is closed, and the upper left extruder 14 and the upper right extruder are respectively according to the calculated formula amount and feeding speed. Extruder 14 feeds. When the material fills the two barrels to form a closed cycle, stop feeding. The material is continuously heated to the temperature required by the process under the shearing and extrusion friction between the screw and the barrel. After the material circulation time in the two extruders 14 is greater than the average residence time of the section, the melt gear pump 10c is turned on to discharge the masterbatch I and the masterbatch II, and at the same time, the two extruders 14 are continuously fed. The masterbatch I and the masterbatch II are cooled and transported for a certain distance and time, and are simultaneously transported to the middle and lower extruders 14 at the same time.

②. The melt gear pump 10c of the extruder 14 in the middle and bottom is turned off, and the extruder 14 in the upper left and the extruder 14 in the upper right are supplied with glue, and the material is continuously fed according to the calculated formula amount and feeding speed. When the material is full of two After the barrel forms a closed cycle, the feeding is stopped and the discharge of the upper left extruder 14 and the upper right extruder 14 is suspended. The material is continuously heated to the temperature required by the process under the shearing and extrusion friction between the screw and the barrel. After the circulation residence time of the extruder 14 in the middle and bottom is longer than the average residence time of this section, the melt gear pump 10c is turned on, and the final rubber compound is discharged according to the calculated flow rate, and at the same time, new material is continuously added at the calculated speed and the extrusion in the upper left is resumed. Outlet 14 and discharge of extruder 14 on the upper right.

When all the materials of the three extruders 14 are continuously connected, the temperature of each section, the cooling water flow, the feeding speed, the screw speed, and the speed of the gear pump are controlled to keep the coordination of each section, so as to form continuous and stable production.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (14)

1. a kind of extruder, including feeding device (4), conveying device, discharging device (10), the feeding device (4) includes adding Hopper (4a) and mixing chamber (4b), it is characterised in that: the conveying device includes at least two machine barrel groups, between each machine barrel group It is arranged in parallel, there are one group or more material conveying mechanism, the mixing chamber (4b) of each machine barrel group and feeding device (4) in each machine barrel group Connection, has interconnected feedback channel (12) between each machine barrel group, the feedback channel (12) make between each machine barrel group with And the material flow passage of circulation can be formed between each machine barrel group and mixing chamber (4b)；Each machine barrel group is made of a machine barrel, or It is connected in series by several machine barrels；The material conveying mechanism includes a screw rod or several screw rods, shearing dispersal unit The combination of (10b), and/or screw rod and shearing dispersal unit；Each screw rod can mutually cooperate with rotation or independent rotation or in the same direction or It reversely rotates；Including at least in the mixing chamber (4b) has two spiral shells connecting across the mixing chamber bottom (4b) with Qu Ji mechanism Bar, screw rod therein can be mutually ratcheting or non-ratcheting.

2. a kind of extruder according to claim 1, it is characterised in that: the machine barrel is the machine barrel of different-diameter or waits straight The machine barrel of diameter, it is also corresponding equal or different to the diameter of its matched screw rod and length.

3. a kind of extruder according to claim 2, it is characterised in that: the end of the screw rod with bearing (13) by connecting It connects, bearing (13) and machine barrel and/or connect and be supported with rack.

4. a kind of extruder according to any one of claims 1 to 3, it is characterised in that: the feedback channel (12) Inside it is provided with the discharging controller of control material flow area size and opening and closing.

5. a kind of extruder according to any one of claims 1 to 3, it is characterised in that: the discharging device (10) For discharging controller, shearing dispersal unit (10b), filter element, constant-current control unit, machine head port mould (10d) wherein it One or its two or more combination.

6. a kind of extruder according to claim 5, it is characterised in that:

Shearing dispersal unit (10b) includes one group or more annulus and disk separately, the outer edge and machine of the annulus Cylinder inner wall is connected and fixed, and intermediate looping pit can allow the axis of screw rod and material to pass through；The center of circle of the disk and the axis of screw rod connect Connect fixation, the outer edge of disk can allow material to pass through, the gap between each annulus and disk be it is fixed and/or adjustable, The surface of the annulus and/or disk that contact with material is smooth surface or has groove or have fin；

The discharging controller is the mechanism of control discharging circulation cross-sectional sizes and opening and closing；

The filter element is the porous material of network-like structure, and the material less than aperture is only allowed to pass through；

The constant-current control unit is smelt gear pump (10c), or is screw pump, or is turbine and worm mechanism；

The machine head port mould (10d) is one of runner, pre-die, the shape of the mouth as one speaks of material or their combination.

7. a kind of extruder according to any one of claims 1 to 3, it is characterised in that: the discharging device (10) At least one or two or more, are set to the end of machine barrel or in any position on the outside of close end, and/or machine barrel.

8. a kind of extruder according to any one of claims 1 to 3, it is characterised in that the parallel of two machine barrel groups The form of setting has: mutual horizontal be set with, or vertical be set with or tilted upward be set with up and down.

9. a kind of extruder according to any one of claims 1 to 3, it is characterised in that: the machine barrel inner cavity is flat It slides or has groove or have the pin (9) for protruding into cylinder lumen.

10. a kind of extruder according to any one of claims 1 to 3, it is characterised in that: in the mixing chamber (4b) Including at least there is two screw rods connecting across the mixing chamber bottom (4b) with Qu Ji mechanism, screw rod therein can it is mutually ratcheting or It is non-ratcheting.

11. a kind of feedback and circulation extrusion process, it is characterised in that squeezed using described in any one of claims 1 to 3 Machine out, extrusion method are as follows: put into material from the loading hopper (4a) of feeding device (4), material is being fed by conveying device After tentatively mixing in the mixing chamber (4b) of device (4), the machine barrel for the conveying device that one of them contains positive extrusion is delivered into, By adjusting positive displacement constant-current control unit, a part of material is discharged from the discharge port of discharging device (10) in proportion, it is another Partial material delivers into the machine barrel containing the conveying device reversely squeezed out by the feedback channel (12) between two machine barrels, returns The mixing chamber (4b) for returning to feeding device (4) converges with the new material being added from loading hopper (4a), by feeding device (4) Mixing chamber (4b) is conveyed and is mixed into the machine barrel of the conveying device squeezed out containing forward direction, and so circulation forms continuous feedback Recycle extrusion process.

12. a kind of intermittent cyclic extrusion process, it is characterised in that using extrusion described in any one of claims 1 to 3 Machine, extrusion method are as follows: first close the discharge port of discharging device (10), material is continuously put into up to being full of from loading hopper (4a) All machine barrel groups, material is by material conveying mechanism in interconnected machine barrel group, feedback channel (12) and feeding device (4) It circulates, continuous circulation after a certain period of time, open, and material is discharged from discharge port by the discharge port of discharging device (10).

13. a kind of parallel extrusion process in the same direction, it is characterised in that use any one of any one of claims 1 to 3 institute The extruder stated, extrusion method are as follows: material is put into from loading hopper (4a), enters two simultaneously by material conveying mechanism It in machine barrel group, and is conveyed simultaneously to discharging device (10) direction, material is discharged from discharge port.

14. a kind of continuous extrusion system of material, it is characterised in that: use claim 11 or 12 or 13 extruders (14) and its corresponding extrusion process it, by the serial or parallel connection of two or several extruders (14), forms between timesharing, multistage charging Tinuous production.