Casting strip unit

Abstract

A cast strip unit comprises a cast strip plate and a distribution plate. A shrinkage cavity and a plurality of straight holes are formed in the two opposite side faces of the cast strip plate correspondingly, the shrinkage cavity is gradually narrowed towards the direction of the straight holes, the straight holes are linearly distributed in the length direction of the cast strip plate, and the inlet ends of the straight holes extend in the thickness direction of the cast strip plate and are connected with the narrow opening ends of the shrinkage cavity. Distribution holes penetrating in the thickness direction of the distribution plate are distributed in the middle area of the surface of one side of the distribution plate, and when the casting strip plate and the distribution plate are connected and attached through a fastener, the wide opening end of the shrinkage cavity is connected with the distribution holes; and a heating piece for directly heating the strip casting plate and the distribution plate is clamped between the strip casting plate and the distribution plate, and is positioned on the outer side of the shrinkage cavity. The cast strip unit is provided with the heating piece, the heat transfer efficiency is high, the temperature of the cast strip unit can be directly controlled, mounting and dismounting are convenient, meanwhile, materials are evenly distributed in the cast strip unit, and operation is smooth.

Description

Technical Field

[0001] The invention relates to the technical field of belt casting heads, in particular to a belt casting unit. Background Art

[0002] The belt casting unit is the main component of the belt casting head. It is mainly connected to the belt casting head cavity by screws. When working, the melt enters from the distribution plate, is distributed and then enters the belt casting plate for extrusion. The more uniform the extruded strips are and the closer the speed is, the better the use effect will be. The existing belt casting unit has the following problems in use: ① Since the medium passing through the casting belt unit is a molten polymer, the temperature of the melt needs to be maintained. The existing casting belt unit can only transfer the heat from the cavity to the casting belt unit through contact with the casting belt head cavity. In this way, the heat transfer efficiency is not high, the temperature of the casting belt unit is low, and it is not easy to maintain. After the material passes through the casting belt unit, the temperature will drop, affecting the discharge effect.

[0003] ② The inner cavity of the cast strip is like a long and thin runway. The closer the melt is to the middle, the faster the speed. Therefore, the extrusion of the entire melt is uneven, affecting the quality of subsequent products.

[0004] ③ Since the material is in a molten state and will volatilize some viscous monomers, it is easy to stick or stay on the casting plate or distribution plate, affecting the smooth discharge of the material.

[0005] To this end, we studied and proposed a casting belt unit. Summary of the invention

[0006] The object of the present invention is to provide a belt casting unit which has a built-in heating element, has high heat transfer efficiency, can directly control the temperature of the belt casting unit, and is easy to install and disassemble.

[0007] The technical solution adopted by the present invention is: a casting strip unit, comprising a casting strip plate and a distribution plate; A contraction cavity and a plurality of straight holes are respectively provided on two opposite sides of the casting strip plate, the contraction cavity gradually narrows its width toward the straight holes, the plurality of straight holes are linearly distributed along the length direction of the casting strip plate, the inlet ends of the straight holes extend along the thickness direction of the casting strip plate and are connected to the narrow end of the contraction cavity; A distribution hole is distributed in the middle area of ​​one side surface of the distribution plate and penetrates along the thickness direction thereof. When the casting strip plate and the distribution plate are connected and attached by fasteners, the wide end of the contraction cavity is connected to the distribution hole. A heating element is clamped between the casting strip plate and the distribution plate for directly heating both of them, and the heating element is located outside the shrinkage cavity.

[0008] As a preferred solution, the heating element is an electric heating rod.

[0009] As a preferred solution, half grooves are respectively provided on the fitting surfaces of the casting strip plate and the distribution plate, and two corresponding half grooves are combined into a straight groove for accommodating the heating element, and the straight groove is along the length direction of the casting strip plate.

[0010] As a preferred solution, the casting belt unit is divided into two symmetrical heating zones in its length direction, and each heating zone is provided with a heating element for independently controlling the temperature of the heating zone.

[0011] As a preferred solution, a temperature measuring module for detecting the temperature of the corresponding heating zone is provided on the side of the casting belt unit.

[0012] As a preferred embodiment, the temperature measurement module includes a platinum thermistor and an insulation board, the insulation board is connected to the end of the casting strip plate or the distribution plate through fasteners, the platinum thermistor is arranged in the mounting hole of the insulation board, and the detection end of the platinum thermistor is in contact with the casting strip plate.

[0013] As a preferred solution, the length of the straight holes gradually shortens from the middle position to both ends of the casting strip plate.

[0014] As a preferred solution, a transition cone surface is provided at the connection between the contraction cavity and the straight hole.

[0015] As a preferred solution, one end of the distribution hole connected to the middle area is chamfered to form a diverter cone surface.

[0016] As a preferred solution, the flow dividing cone surfaces of adjacent distribution holes are connected to each other, so that the middle area has no flat surface.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. A heating element is set on the casting belt unit to directly heat the casting belt unit, with high heat transfer efficiency; The straight-through groove for accommodating the heating element is composed of two opposite half grooves on the casting strip plate and the distribution plate. The disassembly of the casting strip plate and the distribution plate makes the half groove separable, which is convenient for the installation and disassembly of the heating element; the half groove is easy to process and does not require deep hole processing equipment. At the same time, it is also convenient to clean the half groove after separation.

[0018] 2. The casting belt unit is divided into two independent heating zones, and a temperature measurement module is set for feedback. The two heating zones can be temperature-controlled separately, and the temperature of the casting belt unit can be fine-tuned at any time to adapt to materials with different viscosities.

[0019] 3. The length of the straight holes in the cast strip plate gradually decreases from the middle to both sides, so the pressure loss in the middle gradually decreases to both sides, and the speed of the material in the middle is fast and the speed on both sides is slow, so the distribution will be more uniform.

[0020] 4. A diverter cone is set on the inlet side of the distribution hole, and the diverter cones of adjacent distribution holes penetrate each other, so that there is no flat surface in the middle area, only connected cones, which can eliminate dead points, thereby avoiding the material from staying on the flat part and ensuring the uniformity and smoothness of distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a front view schematic diagram of the present invention as a whole; Figure 2 for Figure 1 Middle AA section view; Figure 3 It is a schematic end view of the present invention as a whole; Figure 4 It is a front view schematic diagram of the distribution plate in the present invention; Figure 5 for Figure 4 BB cutaway diagram; Figure 6 It is a schematic diagram of the cast strip plate in the present invention; Figure 7 for Figure 6 Middle CC cutaway diagram; Figure 8 for Figure 6 Middle DD cutaway diagram; Fig. 9 It is a thumbnail schematic diagram of DD section; Fig.10 It is a schematic plan view of the central region of the present invention; Fig.11 It is a three-dimensional schematic diagram of the middle area of ​​the present invention.

[0023] Reference numerals: 1. cast strip plate, 101. contraction cavity, 102. straight hole, 103. transition cone surface; 2. distribution plate, 201, middle region, 202, distribution hole, 203, flow dividing cone surface; 3. Heating element; 4. Platinum thermal resistor; 5. Heat insulation board. DETAILED DESCRIPTION

[0024] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that, without further description, elements, structures and features in one embodiment may also be beneficially combined in other embodiments.

[0025] It should be noted that: unless otherwise defined, the technical terms or scientific terms used in this document shall have the usual meanings understood by people with ordinary skills in the field to which the invention belongs. The words "one", "an" or "the" and the like used in the patent application specification and claims of the present invention do not express quantity restrictions, but indicate the existence of at least one; the words "first", "second" and "third" used in this document shall not be regarded as restrictions on the order of components, but are only used to distinguish different components; words such as "include" or "comprise" and the like indicate that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, but do not exclude other elements or objects with the same function.

[0026] In order to more clearly describe the specific structural composition of the casting belt unit, Figure 1-11 Describe this embodiment: like Figure 1-8 As shown, a casting strip unit comprises a casting strip plate 1 and a distribution plate 2. Two opposite sides of the casting strip plate 1 are respectively provided with a contraction cavity 101 and a plurality of straight holes 102. The contraction cavity 101 gradually narrows its width toward the straight hole 102 ( Figure 7 The cross-sectional width of the middle contraction cavity 101 gradually decreases from right to left), multiple straight holes 102 are linearly distributed along the length direction of the cast strip plate 1, and the inlet end of the straight hole 102 extends along the thickness direction of the cast strip plate 1 and is connected to the narrow end of the contraction cavity 101; the middle area 201 of the surface of one side of the distribution plate 2 is distributed with distribution holes 202 that penetrate along its thickness direction. When the cast strip plate 1 and the distribution plate 2 are connected and fitted by fasteners, the wide end of the contraction cavity 101 is connected to the distribution holes 202; the material passes through the distribution holes 202, the contraction cavity 101 and the straight holes 102 in sequence from inlet to outlet, and the incoming material is homogenized through the distribution holes 202, converged and compressed through the contraction cavity 101, and then extruded through the straight holes 102.

[0027] Bolt holes 6 are arranged opposite to each other at the edges of the casting strip plate 1 and the distribution plate 2. The opposite bolt holes 6 are connected by fasteners 7. The casting strip plate 1 and the distribution plate 2 can be separated by removing the fasteners. The fasteners can be bolt-nut assemblies or buckles.

[0028] See also Figure 1 and Figure 2 A heating element 3 is clamped between the strip casting plate 1 and the distribution plate 2 to directly heat the two, and the heating element 3 is located outside the contraction cavity 101. The heating element 3 is arranged on the strip casting unit to directly heat the strip casting unit, and heat transfer is not required in the strip casting head cavity, so the heating efficiency is high and the temperature is easy to maintain; Specifically, the heating element 3 is an electric heating rod, and half grooves 9 are respectively provided on the bonding surfaces of the casting strip plate 1 and the distribution plate 2. Two corresponding half grooves 9 are combined into a straight groove for accommodating the heating element 3, and the straight groove is along the length direction of the casting strip plate 1. The straight groove for accommodating the heating element 3 is composed of two opposite half grooves 9 on the casting strip plate 1 and the distribution plate 2. The disassembly of the casting strip plate 1 and the distribution plate 2 makes the half grooves 9 separable, which is convenient for the installation and disassembly of the heating element 3, and there will be no burning, difficult disassembly and other phenomena; the half grooves 9 are easy to process, and only two semicircles need to be milled out on the casting strip plate 1 and the distribution plate 2 respectively, and no deep hole processing equipment is required. At the same time, the half grooves 9 are also easy to clean after separation.

[0029] See also Figure 1 Furthermore, the casting strip unit is bounded by the center position in its length direction ( Figure 1 The dotted line in the figure is divided into two symmetrical heating zones, each of which is provided with a heating element 3 for independently controlling the temperature of the heating zone. There are four heating elements 3 in the figure, and the inner side end of each heating element 3 extends to the dividing line in the middle of the straight groove; The side of the casting belt unit is equipped with a temperature measuring module to detect the temperature of the corresponding heating zone. The casting belt unit is divided into two independent heating zones, and a temperature measuring module is set for feedback. The two heating zones can be controlled separately, and the temperature of the casting belt unit can be fine-tuned at any time to adapt to materials with different viscosities; See also Figure 1 and Figure 3 Specifically, the temperature measurement module includes a platinum thermal resistor 4 and a heat insulation board 5. The heat insulation board 5 is connected to the end of the casting strip plate 1 or the distribution plate 2 by fasteners. The platinum thermal resistor 4 is arranged in the mounting hole of the heat insulation board 5, and the detection end of the platinum thermal resistor 4 is in contact with the casting strip plate 1. Bolt countersunk holes are arranged at the end of the casting strip plate 1 or the distribution plate 2, so that the heat insulation board 5 can be fixed on the casting strip plate 1 or the distribution plate 2 by fasteners 8. The heat insulation board 5 plays the role of supporting the platinum thermal resistor 4. At the same time, the heat insulation board 5 does not transfer heat to the detection end of the platinum thermal resistor 4, so as to ensure the accuracy of the platinum thermal resistor 4 in detecting the temperature of the casting strip plate 1 or the casting strip unit; the platinum thermal resistor is interlocked with the electric heating rod to ensure that the temperature of each heating zone can be adjusted, so that the temperature of the casting strip unit can be accurately adjusted to ensure the distribution and extrusion of the material.

[0030] See also Figure 8 and Fig. 9 , the length of the straight hole 102 gradually shortens from the middle position of the casting strip plate 1 to both ends. The inner cavity of the casting strip plate is like a long and thin runway. The closer the melt is to the middle, the faster the speed. In order to strengthen the distribution of materials and make the extrusion more uniform, it is known through experiments and analysis that the length and aperture of the straight hole section are the main factors affecting the pressure loss. However, the aperture directly determines the size of the particles and cannot be changed at will. Therefore, the length of the straight hole section is designed to decrease, ensuring that the pressure loss is getting smaller from the middle to the two sides. In this way, when extruding, it can be ensured that the closer the speed is, the more uniform the extruded material will be; in Fig. 9 In the figure, d1 is the length of the straight hole in the middle position, and d2 is the length of the straight hole at the edge position. After transition design, the length of d2 is smaller than d1.

[0031] In order to ensure smooth flow of materials through the casting unit, the following improvements were made: See also Fig. 9 A transition cone 103 is provided at the connection between the contraction cavity 101 and the straight hole 102. On the length section of the cast strip plate 1, the straight hole 102 is designed to be expanded, thereby reducing the width of the adjacent interval part at the inlet end of the straight hole 102 and forming a cone surface, so that the material has little obstruction when moving toward the straight hole 102; In order to further ensure that the material flows unimpeded in the contraction cavity 101, in the specific design, the contraction cavity 101 is formed by connecting the tapered holes 1011 distributed linearly along the length direction of the casting strip plate 1, and the adjacent tapered holes 1011 are connected at least at their large inner diameter ends, the large inner diameter ends face the distribution plate 2, and the small inner diameter ends correspond to the connected straight holes 102. When the material moves from the tapered holes 1011 to the straight holes 102, there is no dead angle in the tapered holes 1011; a recessed area is set on the side of the casting strip plate 1 facing the distribution plate 2, so that the axial lengths of all the tapered holes 1011 (the same as the length direction of the straight holes 102) are equal, so as to avoid the inconsistent material pressure in the tapered holes 1011 affecting the improvement of the length of the straight holes 102; See also Fig.10 and Fig.11 , a diverter cone 203 is formed by chamfering one end (the inlet section of the material) of the distribution hole 202 connected to the middle area 201, and the diverter cones 203 of adjacent distribution holes 202 are connected to each other, so that the middle area 201 has no plane, only connected cones, which can eliminate dead points, thereby avoiding the retention of materials on the plane part, and ensuring the uniformity and smoothness of distribution; the straight holes 102 at the central area 201 can be specifically distributed in a honeycomb shape, so that the number of holes that can be arranged can be maximized, and the screening rate is better. In this way, the material distributed through the distribution plate 2 will be more reasonable and uniform. When the straight holes 102 are distributed in a honeycomb shape, the diverter cone 203 is also more uniform, and along the axial direction of the straight holes 102 (i.e. Fig.10 From the perspective shown in the figure, the boundary lines of the split cone surfaces 203 after penetrating each other are hexagonal; When the material is extruded, some monomers are easily volatilized. These monomers have a certain viscosity and sometimes adhere to the cast strip plate 1. After a long time, they will be oxidized. After accumulating to a certain weight, they will fall onto the strip and enter the pelletizer for pelletizing with the strip, affecting the performance of the material. Therefore, in order to reduce the adhesion of monomers, we perform a special coating treatment on the cast strip plate 1. The coating can prevent adhesion. At the same time, the coating can also increase the hardness and wear resistance of the cast strip plate 1, which is convenient for polishing the cast strip plate. The better the smoothness of the cast strip plate, the less likely the cast strip plate is to adhere.

[0032] The parts not described in detail in the above embodiments are prior art.

[0033] It should be noted that although the present invention is described by the above embodiments, the present invention may also have other various embodiments. Without departing from the spirit and scope of the present invention, it is obvious that those skilled in the art may make various corresponding changes and deformations to the present invention, but these changes and deformations should all fall within the scope of protection of the appended claims of the present invention and their equivalents.

Claims

1. A belt casting unit, characterized in that: It comprises a casting strip plate (1) and a distribution plate (2); A contraction cavity (101) and a plurality of straight holes (102) are respectively provided on two opposite sides of the casting strip plate (1); the contraction cavity (101) gradually narrows in width in the direction of the straight holes (102); the plurality of straight holes (102) are linearly distributed along the length direction of the casting strip plate (1); the inlet ends of the straight holes (102) extend along the thickness direction of the casting strip plate (1) and are connected to the narrow end of the contraction cavity (101); A distribution hole (202) is distributed in a middle region (201) of a surface of one side of the distribution plate (2) and penetrates along the thickness direction thereof. When the casting strip plate (1) and the distribution plate (2) are connected and affixed by fasteners, the wide end of the contraction cavity (101) is connected to the distribution hole (202); A heating element (3) for directly heating the casting strip plate (1) and the distribution plate (2) is clamped between the casting strip plate (1) and the distribution plate (2), and the heating element (3) is located outside the shrinkage cavity (101).

2. A belt casting unit according to claim 1, characterized in that: The heating element (3) is an electric heating rod.

3. A belt casting unit according to claim 1, characterized in that: Half grooves (9) are respectively provided on the mating surfaces of the casting strip plate (1) and the distribution plate (2); two corresponding half grooves (9) are combined into a straight groove for accommodating the heating element (3); the straight groove is along the length direction of the casting strip plate (1).

4. A belt casting unit according to claim 1, characterized in that: The casting belt unit is divided into two symmetrical heating zones in the length direction thereof, and each heating zone is provided with a heating element (3) for independently controlling the temperature of the heating zone.

5. A belt casting unit according to claim 4, characterized in that: A temperature measuring module for detecting the temperature of the corresponding heating zone is provided on the side of the casting belt unit.

6. A belt casting unit according to claim 5, characterized in that: The temperature measurement module comprises a platinum thermal resistor (4) and a heat insulation plate (5), wherein the heat insulation plate (5) is connected to the end of the casting strip plate (1) or the distribution plate (2) via a fastener, the platinum thermal resistor (4) is arranged in a mounting hole of the heat insulation plate (5), and the detection end of the platinum thermal resistor (4) is in contact with the casting strip plate (1).

7. A belt casting unit according to claim 1, characterized in that: From the middle position to the two ends of the casting strip plate (1), the length of the straight hole (102) gradually shortens.

8. A belt casting unit according to claim 1, characterized in that: A transition cone surface (103) is provided at the connection between the contraction cavity (101) and the straight hole (102).

9. A belt casting unit according to claim 1, characterized in that: One end of the distribution hole (202) connected to the middle area (201) is chamfered to form a flow dividing cone surface (203).

10. A belt casting unit according to claim 9, characterized in that: The flow dividing cone surfaces (203) of adjacent distribution holes (202) are connected to each other, so that the middle area (201) has no flat surface.

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