Double-screw extruder bushing and pouring structure thereof

Abstract

The utility model discloses a double-screw plastic extruding machine lining and a pouring structure thereof, and belongs to the technical field of lining pouring production. The bushing comprises a bushing body and a transversely-through bushing inner hole, and further comprises riser patching protruding sections which are arranged on the two sides of the middle of the bushing body and are formed in a symmetrical side pouring mode. The pouring structure comprises a dead head and a bushing cavity matched with the bushing body in shape, and an inner pouring gate is arranged at the joint of the bushing cavity and the dead head; a riser patch matched with the raised section of the riser patch in shape is arranged on the periphery of the bushing cavity at the inner gate in an up-down semi-surrounding manner, and the riser is fixedly connected with the riser patch at the inner gate; the problem of looseness of the bushing of the double-screw plastic extruding machine is solved by adding the outer patch, and the riser patch is added to guide and relax the molten iron to the highest point and the farthest end to flow to a channel, so that more molten iron is conveyed to the highest point and the farthest end. The technical problems that the service life is short and the cleanliness of extrusion molding raw materials is affected due to the fact that the interior of a bushing casting of the double-screw plastic extruding machine is loose are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of bushing casting production, more specifically to a twin-screw extruder bushing and a casting structure thereof. Background Art

[0002] With the rapid development of global rubber and plastic, chemical, wood plastic, building materials and other industries, these industries are equipped with a large number of twin-screw extruders, and the bushing is a wear-prone part of the twin-screw extruder. Figure 1 As shown, the bushing includes a bushing body 10 and a bushing inner hole 11 extending transversely therethrough. The middle portion of the bushing inner hole 11 is a feeding portion 12. As the name implies, the feeding portion 12 usually requires a riser for feeding. Currently, there are two feeding methods:

[0003] Traditional solution 1: vertical pouring, such as Figure 2 As shown, external subsidies (marked in yellow) are added, but the disadvantages of this method are: ① the casting has a large draft angle, which requires a large amount of processing, and high-chromium cast iron is difficult to process; ② the castings vary in length, which is difficult for manufacturers using flasks; ③ the longer the casting, the larger the subsidy required for vertical pouring, and the more difficult it is to remove the subsidy; ④ the mud core is difficult to fix when it is vertical, and it is easy to deviate to one side, resulting in uneven wall thickness of the casting, and wall thickness is a critical dimension;

[0004] Traditional solution 2: side pouring, such as Figure 3 As shown in the figure, although the pouring and rising are integrated (the pouring gate is through the riser or a riser is added above the pouring gate, and hot molten iron continuously replenishes the riser during the pouring process), the looseness inside the casting cannot be completely solved.

[0005] The inner hole 11 of the bushing is a key usage part. The looseness of the inner hole (small holes) will not only reduce its service life, but also affect the cleanliness of the raw materials (if there are holes in the inner hole 11 of the bushing, when producing material A, material A will remain in the hole, affecting the color and performance of material B produced next time). Utility Model Content

[0006] 1. Technical problems to be solved by the utility model:

[0007] In response to the problems that the internal looseness of bushing castings produced by existing casting processes leads to short service life and affects the cleanliness of extruded raw materials, the utility model provides a twin-screw extruder bushing and its casting structure. By adding a special riser to the casting structure, the flow rate and direction of molten iron during pouring are guided, thereby achieving the purpose of making the bushing casting dense, uniform and free of micropores in all directions.

[0008] 2. Technical solution:

[0009] In order to achieve the above-mentioned purpose, the technical solution provided by the present utility model is:

[0010] A twin-screw extruder bushing in the present technical solution comprises a bushing body and a bushing inner hole extending transversely therethrough, and also comprises riser-complementary raised sections symmetrically formed by side casting on both sides of the middle of the bushing body.

[0011] According to a further technical solution, the riser compensation raised section is an arc-shaped section whose thickness gradually decreases from the middle to the upper and lower sides.

[0012] A casting structure for the above-mentioned twin-screw extruder bushing includes a riser and a bushing cavity that is adapted to the shape of the bushing body, and the connection between the bushing cavity and the riser is an inner gate; on the periphery of the bushing cavity at the inner gate, riser subsidies that are adapted to the shape of the riser subsidy protrusion section are arranged in an upper and lower semi-surrounding manner, and the riser and the riser subsidies are fixedly connected at the inner gate.

[0013] Further casting structure, the riser subsidy includes an integrally connected subsidy middle section and subsidy transition sections on its upper and lower sides; the subsidy middle section is a rectangular section, and the subsidy transition section is a semi-arc section with a thickness gradually decreasing toward both sides, and the curvature is respectively adapted to the upper and lower parts of the bushing cavity.

[0014] Further, in the casting structure, the width L of the riser subsidy is 1 / 4 to 1 / 3 of the length of the bushing cavity; the thickness H of the middle section of the subsidy is 1 / 25 to 2 / 25 of the width L.

[0015] A casting method for a twin-screw extruder bushing comprises the following steps:

[0016] After the mold including the above casting structure is subjected to sand mixing, sand casting and box assembly, a bushing cavity is formed inside the molding sand, and side cavities in the shape of risers are formed on both sides of the bushing cavity;

[0017] During pouring, after the molten iron enters the bushing cavity and the side cavities on both sides through the pouring channel, the pouring structure widens the flow channel of the molten iron to the highest point of the bushing cavity and on both sides of its length direction, which can transport more molten iron to the highest point and on both sides of its length direction, making the flow of molten iron smoother, guiding the flow rate and direction of molten iron during pouring, and thus achieving the technical effect of making the bushing body all-round dense, uniform and free of micropores.

[0018] A further pouring method is provided, wherein the pouring temperature is 1500-1550°C.

[0019] 3. Beneficial effects:

[0020] Compared with the prior art, the technical solution provided by this utility model has the following beneficial effects:

[0021] The casting structure and casting method of the twin-screw extruder bushing of the utility model solve the looseness problem of the twin-screw extruder bushing by adding external subsidies, and increase the riser subsidies to guide and relax the flow channel of molten iron to the highest point and the farthest end, so as to transport more molten iron to the highest point and the farthest end, thereby achieving the technical effect of all-round shrinkage compensation of the bushing and dense internal without micropores. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a twin-screw extruder bushing in the prior art;

[0023] Figure 2 It is a schematic diagram of the structure of a vertical casting mold for a twin-screw extruder bushing in the prior art;

[0024] Figure 3 This is a schematic diagram of the side casting mold structure of the twin-screw extruder bushing in the prior art;

[0025] Figure 4 for Figure 3 Schematic diagram of the local cross-sectional structure.

[0026] Figure 5 A schematic diagram of the casting structure of a twin-screw extruder bushing according to a specific embodiment;

[0027] Figure 6 for Figure 5 Schematic diagram of the local structure.

[0028] Figure 7 for Figure 6 A side structural diagram of

[0029] Figure 8 It is a schematic diagram of the structure of a twin-screw extruder bushing according to a specific embodiment.

[0030] In the figure: 1. Bushing cavity; 2. Riser subsidy; 3. Riser; 5. Mud core; 6. Runner; 10. Bushing body; 11. Bushing inner hole; 12. Shrinkage compensation part; 20. Riser subsidy raised section; 21. Subsidy middle section; 22. Subsidy transition section; 31. Ingate. DETAILED DESCRIPTION

[0031] In order to further understand the content of the utility model, the utility model is described in detail with reference to the accompanying drawings.

[0032] Example

[0033] The twin-screw extruder bushing of the present embodiment is as follows Figure 8As shown, the bushing comprises a bushing body 10 and a bushing inner hole 11 extending transversely therethrough, as well as riser-subsiding protrusions 20 symmetrically formed by side-casting on both sides of the middle portion of the bushing body 10. The riser-subsiding protrusions 20 are arc-shaped segments whose thickness gradually decreases from the middle portion toward the upper and lower sides, and their curvatures are adapted to the upper and lower portions of the bushing body 10, respectively.

[0034] The twin-screw extruder bushing of this embodiment is made by a special casting structure through a casting process, such as Figure 5 As shown, the casting structure includes a riser 3 and a bushing cavity 1 that is adapted to the shape of the bushing body 10. The connection between the bushing cavity 1 and the riser 3 is an inner gate 31. Riser subsidies 2 that are adapted to the shape of the riser subsidy protrusion 20 are arranged in an upper and lower semi-circular manner on the periphery of the bushing cavity 1 at the inner gate 31. The riser 3 and the riser subsidy 2 are fixedly connected at the inner gate 31. The riser subsidy 2 includes an integrally connected subsidy middle section 21 and subsidy transition sections 22 on its upper and lower sides. The subsidy middle section 21 is a rectangular section, and the subsidy transition section 22 is a semi-arc section with a thickness gradually decreasing toward both sides, and the curvature is adapted to the upper and lower parts of the bushing cavity 1, respectively. As shown Figure 6 、 7 As shown, the width L of the riser patch 2 is 1 / 4 to 1 / 3 of the length of the bushing cavity 1; the thickness H of the patch middle section 21 is 1 / 25 to 2 / 25 of the width L, effectively guiding both the flow rate and direction of molten iron pouring. For example, when manufacturing a 4.95 model bushing for a twin-screw extruder, the width L of the riser patch 2 is preferably 125 mm, and the thickness H of the patch middle section 21 is preferably 8 mm, achieving optimal guidance of the flow rate and direction of molten iron pouring to the bushing cavity 1 without blind spots.

[0035] The casting process of the twin-screw extruder bushing of this embodiment comprises the following steps:

[0036] Step 1: After the mold including the above-mentioned casting structure is mixed with sand, molded and assembled, a hollow structure of the bushing cavity 1 is formed inside the molding sand, and side cavities in the shape of riser patches 2 are generated on both sides of the bushing cavity 1;

[0037] Step 2: During pouring, the molten iron pouring temperature is 1500-1550℃. After the molten iron enters the bushing cavity 1 and the side cavities on both sides through the runner 6, the pouring structure relaxes the molten iron flow channel to the highest point of the bushing cavity 1 and the far ends on both sides of its length direction.

[0038] like Figure 4 As shown in the figure, in the side casting mold of the prior art, except for the riser direct feeding portion 12 in the red circle, the other parts of the bushing cavity 1 are all thin-walled. Although the riser feeding portion 12 is relatively thick, it is difficult for the riser to feed the thin-walled position at the highest point and the farthest end of the product. Figure 5As shown, the special pouring structure of the twin-screw extruder bushing of this embodiment increases the thickness of the product at the riser 3 by adding the riser subsidy 2, so that the molten iron in this part gradually solidifies slowly from the middle to both sides, and then this part of the molten iron is pushed to the highest point and the farthest thin-wall position in stages. The molten iron pouring temperature is 1500-1550℃, which cooperates with the special pouring structure to enable the molten iron to be transported in stages along the semi-arc-shaped subsidy transition section 22 to reach the highest point and both sides of its length direction, so that the circulation of the molten iron is smoother, and then the flow rate and flow direction of the molten iron during pouring are guided to the bushing cavity 1 without dead angles.

[0039] Through cross-section metallographic examination, the 4.95 model bushing of the twin-screw extruder manufactured by the corresponding casting process through the above casting structure has a dense and uniform overall internal structure without obvious micropores.

[0040] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure and manufacturing steps are not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the inventive purpose of the present invention, designs a structure and embodiment similar to the technical solution without creatively designing, they shall fall within the scope of protection of the present invention.

Claims

1. A twin-screw extruder bushing, comprising a bushing body (10) and a bushing inner hole (11) extending transversely therethrough, characterized in that: It also includes riser-complementary raised sections (20) formed by symmetrical side casting on both sides of the middle of the bushing body (10).

2. The twin-screw extruder bushing according to claim 1, characterized in that: The riser supplement convex section (20) is an arc-shaped section whose thickness gradually decreases from the middle to the upper and lower sides.

3. A casting structure for a twin-screw extruder bushing according to claim 1 or 2, characterized in that: The invention comprises a riser (3) and a bushing cavity (1) in the shape of an adaptable bushing body (10); the connection between the bushing cavity (1) and the riser (3) is an ingate (31); riser patches (2) in the shape of an adaptable riser patch convex section (20) are arranged in an upper and lower semi-circular manner on the periphery of the bushing cavity (1) at the ingate (31); the riser (3) and the riser patches (2) are fixedly connected at the ingate (31).

4. The casting structure according to claim 3, characterized in that: The riser subsidy (2) comprises an integrally connected subsidy middle section (21) and subsidy transition sections (22) on its upper and lower sides; the subsidy middle section (21) is a rectangular section, and the subsidy transition section (22) is a semi-arc section with a thickness gradually decreasing toward both sides, and the curvature is respectively adapted to the upper and lower parts of the bushing cavity (1).

5. The casting structure of the twin-screw extruder bushing according to claim 4, characterized in that: The width L of the riser patch (2) is 1 / 4 to 1 / 3 of the length of the bushing cavity (1); the thickness H of the patch middle section (21) is 1 / 25 to 2 / 25 of the width L.

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