TWIN-SCREW EXTRUDER

Abstract

In order to provide a twin-screw extruder that can also be effectively used for a use, such as straining, since suppressing an increase in load power and the generation of heat of a material in a hopper unit and increasing pressure for extruding a material from a material outlet in a compression unit, the size of the lead angle of a screw blade at the position of the compression unit is set to be larger than the size of the lead angle of the screw blade at the position of the hopper unit 11 and the screw blade is disposed at the position of the compression unit so as to be wound two or more times.

Claims

1. A twin-screw extruder comprising: two screw shafts that are rotatably provided in a casing including a hopper unit and a compression unit, the hopper unit being provided with a material inlet, the compression unit being subsequent to the hopper unit and being provided with a material outlet at a tip thereof, and each of the screw shafts being provided with a tapered screw blade, wherein the size of a lead angle of the screw blade at the position of the compression unit is set to be smaller than the size of a lead angle of the screw blade at the position of the hopper unit, and the screw blade is disposed at the position of the compression unit so as to be wound two or more times.

2. The twin-screw extruder according to claim 1, wherein the lead angle of the screw blade at the position of the compression unit is set to the range of 10 to 24.

3. The twin-screw extruder according to claim 1 or 2, wherein the length of the compression unit is set to 2.5 times or more the dimension of the radius of an inner wall of a tip portion of the casing.

4. The twin-screw extruder according to claim 1, wherein the thickness of the screw blade at the position of the compression unit is set to be larger than the thickness of the screw blade at the position of the hopper unit.

5. The twin-screw extruder according to claim 1, wherein a mesh screen is detachably provided in the material outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIGS. 1A and 1B show an example of a twin-screw extruder of the invention, FIG. 1A is a view showing the entire twin-screw extruder, and FIG. 1B is a plan view of a hopper unit.

[0022] FIG. 2 is a plan sectional view of the twin-screw extruder.

DETAILED DESCRIPTION

[0023] An embodiment of a twin-screw extruder of the invention will be described below with reference to drawings.

[0024] FIGS. 1 to 2 show an example of a twin-screw extruder of the invention.

[0025] As in the case of the twin-screw tapered extruder in the related art, the twin-screw extruder is adapted so that two screw shafts 2 are rotatably provided in a casing 1 including a tapered cylinder-shaped hopper unit 11 and a tapered cylinder-shaped compression unit 12. The hopper unit 11 is provided with a material inlet 11a, the compression unit 12 is subsequent to the hopper unit 11 and is provided with a material outlet 12a at a tip thereof, and each of the screw shafts 2 is provided with a tapered screw blade 21.

[0026] Further, in this example, the size of the lead angle 2 of the screw blade 21 at the position of the compression unit 12 is set to be smaller than the size of the lead angle 1 of the screw blade 21 at the position of the hopper unit 11 (which is the same as in the twin-screw tapered extruder in the related art) and the screw blade 21 is disposed at the position of the compression unit 12 so as to be wound two or more times.

[0027] Here, the sizes of the lead angles 1 and 2 are not particularly limited. The lead angle 1 is set to the range of 25 to 50 and is preferably set to the range of about 30 to 45, and the lead angle 2 is set to the range of 10 to 24 and is preferably set to the range of about 12 to 20.

[0028] Further, the number of turns of the screw blade 21 at the position of the compression unit 12 is set to two or more, is preferably set to the range of 2 to 4, and is more preferably set to the range of 2 to 3.

[0029] Accordingly, a function to crush a massive material, which is input from the material inlet 11a, and to supply the crushed material to the compression unit 12 can be displayed at the position of the hopper unit 11; and a function to compress the material, to generate pressure required for extruding the material from the material outlet 12a, and to ensure the amount of the material, which is to be processed, by suppressing the back flow of the material can be displayed at the position of the compression unit 12.

[0030] In this case, the length L of the compression unit 12 is set to 2.5 times or more the dimension of the radius r of an inner wall of the tip portion of the casing 1 (a distance between the axis of the screw shaft 2 and an inner wall surface 12b of the tip portion of the casing 1), is preferably set to the range of 3.0 to 6.0 times the radius r, and is more preferably set to the range of 3.5 to 5.0 times the radius r.

[0031] Accordingly, the function to ensure the amount of the material, which is to be processed, by reliably suppressing the back flow of the material can be displayed.

[0032] Further, the thickness t2 of the screw blade 21 at the position of the compression unit 12 is set to be larger than the thickness t1 of the screw blade 21 at the position of the hopper unit 11.

[0033] That is, the thickness t1 of the screwblade 21 at the position of the hopper unit 11 is set to be substantially the same as that of the twin-screw tapered extruder in the related art; and the thickness t2 of the screw blade 21 at the position of the compression unit 12 is set to the range of about 1.5 to 3.0 times the thickness t1 and is preferably set to the range of about 1.8 to 2.5 times the thickness t1.

[0034] Accordingly, pressure for extruding the material from the material outlet 12a can be further increased.

[0035] Since the screw blade 21 is generally formed by mounting a plate-like member on the screw shaft 2 by welding or the like, each of the thickness t1 of the screw blade 21 at the position of the hopper unit 11 and the thickness t2 of the screw blade 21 at the position of the compression unit 12 is set to be constant as in this example. However, in a case in which the screw blade 21 is formed by cutting or the like, the screw blade 21 can also be formed so that the thickness of the screw blade 21 is gradually increased toward a tip side from a base end side.

[0036] According to this twin-screw extruder, the twin-screw extruder has a function to crush a massive material, which is input from the material inlet 11a of the hopper unit 11, and to smoothly supply the crushed material to the compression unit 12 as in the case of the twin-screw tapered extruder in the related art, and can prevent the back flow of a material in the compression unit 12 and increase pressure for extruding the material from the material outlet 12a.

[0037] Accordingly, the twin-screw extruder can also be used for a use in which high extrusion pressure is required.

[0038] Specifically, as shown in FIG. 1A, a mesh screen 31 is disposed in the material outlet 12a and a material from which foreign matters have been removed can be supplied to a roller head 4, which is provided on the rear stage of the material outlet 12a, through the mesh screen 31.

[0039] In this case, the mesh screen 31 is adapted to be capable of being moved in a horizontal direction by a slide mechanism 32 and is adapted to be capable of being alternately used and cleaned.

[0040] Accordingly, since it is possible to remove foreign matters that are contained in a material by a series of processes, it is possible to improve the quality of the material and to shorten a process.

[0041] The twin-screw extruder of the invention has been described above on the basis of the example thereof. However, the invention is not limited to the structure disclosed in the example, and the structure of the invention can also be appropriately modified without departing from the scope of the invention.

[0042] The twin-screw extruder of the invention can suppress an increase in load power and the generation of heat of a material in the hopper unit and can increase pressure for extruding a material from the material outlet in the compression unit. Accordingly, the twin-screw extruder of the invention can be suitably used for a use in which high extrusion pressure is required as in a case in which a mesh screen is provided in the material outlet to remove foreign matters contained in the material.

[0043] It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.