CN108000836B - Melt delivery flow balance compensation method and stabilizing device for eccentric rotor extruder - Google Patents

Abstract

The invention discloses a melt delivery flow balance compensation method and a stabilizing device of an eccentric rotor extruder. The method is to divide the eccentric rotor into a melting and plasticizing section and a flow balancing section. The eccentricity of the section makes the two chambers at the flow balance section communicate through the gap. When the pressure of one chamber increases, part of the molten material will flow to the other chamber through the gap under the action of pressure. In order to achieve flow balance compensation. In the device, the eccentricity of the flow balance section on the eccentric rotor is greater than the eccentricity of the melting and plasticizing section; in the melting and plasticizing section, the diameter of the eccentric rotor is equal to the short intercept of the inner cavity of the stator; in the flow balancing section, the diameter of the eccentric rotor less than the short intercept of the stator lumen. The invention effectively solves the problems of flow fluctuation and unbalanced extrusion flow of an eccentric rotor extruder, realizes stable melt extrusion, is beneficial to improving the surface uniformity and dimensional stability of products, and improves product quality.

Description

Melt delivery flow balance compensation method and stabilizing device for eccentric rotor extruder

technical field

The invention relates to the technical field of polymer material extrusion molding, in particular to a melt delivery flow balance compensation method and a stabilizing device for an eccentric rotor extruder.

Background technique

The Chinese invention patent application with the application number 201410206552.8 discloses a transport method and device for eccentric rotor volume pulsation deformation plasticization, which adopts a new method and new theory of polymer processing, so that polymer materials can be processed in the entire plasticization process. is dominated by volumetric fluctuations. This patent utilizes the rolling action of the eccentric rotor in the inner cavity of the stator during its rotation and constant-velocity reverse revolution, so that the volume of the material between the eccentric rotor and the stator changes periodically along the axial and radial directions of the stator alternately, realizing the volume of the material Pulsating deformation plastic transport. The eccentric rotor equipment includes a stator and a rotor placed in the inner cavity of the stator; the rotor includes a plurality of alternately arranged rotor eccentric helical segments and a plurality of rotor eccentric straight segments; the stator inner cavity includes a plurality of alternately arranged stator helical segments and a plurality of stators Straight line section; the rotor eccentric spiral section and the rotor eccentric straight section correspond to the stator spiral section and the stator straight section; along the conveying direction of the material, the pitch of each rotor eccentric spiral section and the stator spiral section gradually decreases; the inner cavity of the stator The radial sections of the helical section and the straight section are all long holes, and the eccentric rotor reciprocates in the long holes in the inner cavity of the stator, and the movement stroke is twice the maximum eccentricity of the rotor.

Since the eccentric rotor rolls in the inner cavity of the stator during its rotation and constant-speed reverse revolution, the space volume between the eccentric rotor and the stator changes periodically along the axial and radial directions of the stator, and the material between the stator and the rotor is periodically It bears the action of volume pulsation deformation during permanent compression and release, and completes the plasticization and transportation process including solid compaction, melt plasticization, mixing and kneading, and melt transportation. Therefore, the above-mentioned eccentric rotor volume pulsating deformation plasticizing transportation device has the characteristics of short thermomechanical course of materials, low energy consumption, and wide adaptability.

However, in practical applications, there is a certain amount of eccentricity between the stator and the eccentric rotor shaft in the above-mentioned eccentric rotor volume pulsating deformation plastic transportation device. In two independent spaces, the center speed of the eccentric rotor presents a sinusoidal periodic change in the slotted section of the stator due to its special motion mode. The periodic change of the motion speed leads to uneven pressure, which makes the fluid extrusion flow unbalanced in the eccentric rotor device. The problem. In addition to the field of polymer processing, the same situation exists in the transportation of other soft substances.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for compensating the flow balance of the melt delivery of the eccentric rotor extruder. out-of-speed balance.

Another object of the present invention is to provide a melt delivery stabilizing device for an eccentric rotor extruder used to realize the above flow balance compensation method.

The technical solution of the present invention is: a melt delivery flow balance compensation method for an eccentric rotor extruder, by dividing the eccentric rotor located at the end of the extruder into a melting and plasticizing section and a flow balancing section, the eccentricity of the flow balancing section (that is, the distance between the central axis of the eccentric rotor at the flow balance section and the central axis of the stator) is greater than the eccentricity of the melting and plasticizing section (that is, the distance between the central axis of the eccentric rotor and the central axis of the stator at the melting and plasticizing section), so that the flow The eccentric rotor at the balance section communicates with the two chambers formed in the inner cavity of the stator through a gap. During the rotation of the eccentric rotor, when the pressure in one of the chambers increases (that is, a high-pressure chamber is formed), part of the molten material will flow in Under the action of pressure, it flows through the gap to another chamber (that is, the low-pressure chamber), so as to realize the balance compensation of the melt delivery flow of the extruder. During the entire molten material conveying process, the eccentric rotor rotates around its own axis and rolls around the axis of the stator in the inner cavity of the stator, so the volumes of the two chambers formed between the eccentric rotor and the inner cavity of the stator are in different radial directions. There will also be changes in cross section.

In the melting and plasticizing section, the two chambers formed by the eccentric rotor in the inner cavity of the stator are mutually independent chambers, and the melted material advances in the form of double parallel helixes in the melting and plasticizing section.

In the melting and plasticizing section, the movement speed of the eccentric rotor changes periodically, so that the pressure of the molten material in the two chambers also fluctuates, and the fluctuation trend of the molten material in the two chambers differs by half a sinusoidal period .

The melt delivery stabilizing device of the eccentric rotor extruder used to realize the flow balance compensation method of the present invention includes an eccentric rotor and a stator. The melting and plasticizing section and the flow balance section connected in sequence, the eccentricity of the flow balancing section is greater than the eccentricity of the melting and plasticizing section; in the melting and plasticizing section, the diameter of the eccentric rotor is equal to the short intercept of the inner cavity of the stator; in the flow balancing section , the diameter of the eccentric rotor is smaller than the short intercept of the stator lumen.

The radial section of the stator cavity is in the shape of a long hole, the long axis of the long hole is the long intercept of the stator cavity, and the short axis of the long hole is the short intercept of the stator cavity.

In the flow balance section, the gap width between the eccentric rotor and the side of the long hole is equal to the cross-sectional diameter difference between the melting and plasticizing section of the eccentric rotor and the flow balance section.

In the eccentric rotor, the pitch of the melting and plasticizing section is greater than the pitch of the flow balancing section.

The length of the flow balancing section is not more than 1/5 of the overall length of the eccentric rotor (the overall length of the eccentric rotor is the sum of the lengths of the melting and plasticizing section and the flow balancing section).

Two helical chambers are formed between the eccentric rotor and the inner cavity of the stator; the two chambers in the melting and plasticizing section are not connected, and the two chambers in the flow balance section are connected.

The eccentric rotor is meshed with the inner cavity of the stator, and the movement stroke of the eccentric rotor in the inner cavity of the stator is as follows: in the melting and plasticizing section, the moving stroke of the eccentric rotor in the inner cavity of the stator is twice the eccentricity of the melting and plasticizing section, The rotor is fully meshed with the stator; in the flow balance section, the movement stroke of the eccentric rotor in the inner cavity of the stator is twice the eccentricity of the flow balance section, and there is a gap between the rotor and the stator.

The above-mentioned melt conveying and stabilizing device is installed at the end of the eccentric rotor extruder. When in use, the principle is: when the molten material passes through the melting and plasticizing section, the molten material is separated in two independent screw groove cavities (that is, the eccentric rotor and the stator) The two chambers formed between the chambers), the molten material presents a double parallel helical advance. Due to the periodic change of the movement speed of the eccentric rotor, the pressure of the molten material fluctuates in the two closed screw groove cavities, and the fluctuation trend differs by half a sinusoidal period. The molten material is affected by the positive displacement and conveying characteristics in the melting and plasticizing section. After entering the flow balance section, its eccentricity is larger than that of the plasticizing and melting section, while the pitch is smaller, and the cross-sectional diameter of the eccentric rotor becomes smaller. Therefore, the eccentric rotor and There is a gap between the side walls of the stator (that is, the gap between the above-mentioned eccentric rotor and the side of the long hole), so the two different screw groove cavities in the flow balance section are connected through the gap, so when the pressure in the flow channel fluctuates, the eccentric In the chambers on both sides of the rotor, the molten material in the high-pressure chamber will flow into the low-pressure chamber through the gap to perform stretching flow pressure balance compensation. After passing through the flow balance section of several lengths, the molten material is stably discharged from the outlet of the extruder.

Compared with the prior art, the present invention has the following beneficial effects:

The melt delivery flow balance compensation method and stabilizing device of the eccentric rotor extruder effectively solve the flow fluctuation and extrusion flow of the eccentric rotor extruder by setting the melting and plasticizing section and the flow balance section with different eccentric distances on the eccentric rotor. The problem of balance, to achieve stable melt extrusion, is conducive to improving the surface uniformity and dimensional stability of the product, and improving the quality of the product.

In the melt conveying and stabilizing device of the eccentric rotor extruder, during the plasticizing and conveying process of the entire melting and plasticizing section, some materials are extruded and flowed in the two chambers, and both the plasticizing and melting sections are subject to stretching flow. Variable effect, effectively improving the mixing effect.

The melt conveying stabilizing device of the eccentric rotor extruder has a simple structure, is less difficult to implement, and is beneficial to popularization and application in a wide range.

Description of drawings

Fig. 1 is a structural schematic diagram of the melt conveying stabilization device of the eccentric rotor extruder.

Fig. 2 is a partial enlarged view of C in Fig. 1 .

Fig. 3 is a schematic diagram of the half-period movement of the eccentric rotor in the inner cavity of the stator on the section A-A in Fig. 1 .

Fig. 4 is a schematic diagram of the half-period movement of the eccentric rotor in the inner cavity of the stator on the B-B section in Fig. 1 .

Detailed ways

The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

Example

In this embodiment, a melt delivery stabilizing device for an eccentric rotor extruder, as shown in Figure 1 or Figure 2, is mainly composed of an eccentric rotor 1 and a stator 2. While the eccentric rotor rotates, it also rotates around the axis of the stator. The reverse revolution movement is carried out in the inner cavity of the stator, and the stator and the eccentric rotor are meshed with each other, that is, no matter in the melting and plasticizing section or the flow balance section, the eccentric rotor is close to the inside of the stator on any radial section of the eccentric rotor. The barrel wall of the chamber moves.

As shown in Figure 1, the end of the eccentric rotor includes a melting and plasticizing section a and a flow balance compensation section b. When the material passes through the melting and plasticizing section, the diameter of the eccentric rotor is equal to the short intercept L of the long hole section of the stator (as shown in Figure 3), and the material is separated into two independent chambers (as shown in Figure 3 The first chamber G1 and the second chamber G2), because the speed of the eccentric rotor changes periodically, the pressure of the material in these two closed chambers also fluctuates, and the fluctuation trend differs by half a sinusoidal period. The cross-sectional view of the flow balance section is shown in Figure 4. After the material enters the flow balance section, its eccentricity e2 is larger than that of the melting and plasticizing section e1, while the screw pitch is smaller, and the cross-sectional diameter of the eccentric rotor is smaller than that of the long hole. Intercept, because there is a gap between the eccentric rotor and the stator, so the pressure is connected between two different chambers (ie, the first chamber G1 and the second chamber G2) through the gap. Therefore, when the pressure in the runner fluctuates, part of the molten material in the high-pressure chamber (the second chamber G2 in this embodiment) flows into the low-pressure chamber (the second chamber G1 in the present embodiment) through the gap to carry out Stretch flow pressure balance compensation to achieve pressure balance.

In this embodiment, the width of the side gap between the eccentric rotor and the long hole section of the stator is equal to twice the difference in eccentricity between the melting and plasticizing section and the flow balancing section, and equal to the diameter difference between the melting and plasticizing section and the flow balancing section. After the first chamber G1 and the second chamber G2 are connected through the gap, the pressure of the two chambers is kept the same, so that the flow rate of the melt extrusion is stabilized and the quality of the extruded product is improved.

As mentioned above, the present invention can be better realized. The above-mentioned embodiment is only a preferred embodiment of the present invention, and is not used to limit the scope of the present invention; Covered by the scope of protection required by the claims of the present invention.

Claims (7)

1. The melt conveying flow balance compensation method of the eccentric rotor extruder is characterized in that an eccentric rotor positioned at the tail end of the extruder is divided into a melting plasticizing section and a flow balance section, wherein the eccentricity of the flow balance section is larger than that of the melting plasticizing section, and the diameter of the eccentric rotor in the melting plasticizing section is equal to the short intercept of an inner cavity of a stator; in the flow balance section, the diameter of the eccentric rotor is smaller than the short intercept of the inner cavity of the stator, so that the eccentric rotor at the flow balance section is communicated with two chambers formed in the inner cavity of the stator through gaps, and when the pressure of one chamber becomes large in the rotation process of the eccentric rotor, part of molten material flows to the other chamber through the gaps under the action of the pressure, thereby realizing the balance compensation of the melt conveying flow of the extruder.

2. The method of compensating for melt flow balance in an eccentric rotor extruder of claim 1 wherein the two chambers formed by the eccentric rotor in the stator cavity in the melt plasticizing section are independent chambers, and the melt material advances in a double parallel spiral in the melt plasticizing section.

3. The method according to claim 2, wherein in the melt plasticizing section, the movement speed of the eccentric rotor is periodically changed, so that the pressure of the molten material in the two chambers is also fluctuated, and the fluctuated trends of the molten material in the two chambers are different by half a sine period.

4. The melt conveying stabilizing device of the eccentric rotor extruder is characterized by comprising an eccentric rotor and a stator, wherein the eccentric rotor is arranged in an inner cavity of the stator, a melt plasticizing section and a flow balancing section which are sequentially connected are arranged on the eccentric rotor along the conveying direction of a molten material, and the eccentric distance of the flow balancing section is larger than that of the melt plasticizing section; in the melting plasticizing section, the diameter of the eccentric rotor is equal to the short intercept of the inner cavity of the stator; in the flow balance section, the diameter of the eccentric rotor is smaller than the short intercept of the inner cavity of the stator;

the radial cross section of the stator inner cavity is in a long hole shape, the long intercept of the stator inner cavity is in the long axis direction of the long hole, and the short intercept of the stator inner cavity is in the short axis direction of the long hole;

in the eccentric rotor, the screw pitch of the melting plasticizing section is larger than that of the flow balancing section.

5. The melt conveying stabilizing device of an eccentric rotor extruder as claimed in claim 4, wherein in said flow balancing section, the gap width between the eccentric rotor and the side of the elongated hole is equal to the difference in cross-sectional diameter between the melt plasticizing section of the eccentric rotor and the flow balancing section.

6. The melt conveying stabilizing device of an eccentric rotor extruder of claim 4, wherein the length of said flow balancing section is no more than 1/5 of the overall length of the eccentric rotor.

7. The melt conveying stabilizing device of an eccentric rotor extruder of claim 4, wherein two spiral chambers are formed between the eccentric rotor and the stator cavity; the two chambers in the melt plasticizing section are not communicated, and the two chambers in the flow balancing section are communicated.