JPH02120006A - Kneading and extruding machine having two-screw-shaft of different diameter - Google Patents

Abstract

PURPOSE:To perform widely and easily control of a degree of kneading, by method wherein the title machine is constituted of a pair of screw shafts, the first and second screw parts whose outside diameters of screw shafts each are different from each other, and a tapered part of an inner wall formed on an inner wall of a cylinder, and provided with a columnar part formed by adjoining to the tapered part, and a cylindrical part of the inner wall formed by adjoining to the tapered part of the inner wall. CONSTITUTION:Tapered parts 7c, 8c and columnar parts 7e, 8e constituting different diametral parts at positions where the outside diameters are changed are formed by adjoining to one another and continuously, in a space between screw parts 5, 6 each in screw shafts 7, 8 each. A gap t1 is formed among the tapered parts 7c, 8c each and a tapered part 1e of an inner wall, a gap t2 is formed among the columar parts 7e, 8e each and cylindrical parts 1ba, 1ca each of the inner wall and effective lengths D overlapping one another are formed. In case of control of a degree of kneading of resin raw materials in kneading parts 7b, 8b, the control can be performed arbitrarily by changing size of the gap t1 and effective length D by moving a cylinder 1 in an axial direction by a hydraulic cylinder 3 and the control of the degree of kneading can be performed by that whose accuracy is comparatively low.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a twin-screw kneading extruder with different diameters, and in particular, the degree of kneading (degree of squeezing) can be widely adjusted by moving the cylinder. The present invention relates to a novel improvement for facilitating the control of axial movement of a cylinder during continuous operation.

[Prior Art] This kind of biaxial kneading extruder with different diameters that has been used in the past is shown in FIG. 4, for example,
The configurations disclosed in Japanese Patent Application Laid-Open No. 83-83 and Japanese Patent Application Laid-Open No. 58-87013 can be mentioned.

That is, in the figure, what is indicated by the reference numeral 1 is a cylinder that is movable in the axial direction by a hydraulic cylinder 3 provided in the main body 2, and within this cylinder 1 are two large diameter shafts. A first shaft hole 1a consisting of a hole and a pair of second shaft holes consisting of two small diameter shaft holes partitioned by a wall 1f.
Shaft holes 1b and 1c are continuously formed.

The rear end 1d of the cylinder 1 is configured to be able to come into contact with a stopper portion 2a formed on the main body 2, and the rear end 1d of the cylinder 1
The moving distance in the axial direction is measured by a dial gauge 4 disposed in contact with the rear end 1d.

In each of the shaft holes 1a to IC, there are first holes having different outer diameters.
A pair of first screw shafts 7 and second screw shafts 8 which integrally have a screw portion 5 and a second screw portion 6 are disposed so as to be freely rotatable while being meshed with each other.
and 8 are connected to the speed reduction mechanism 9 via a connecting shaft 10, and are provided in a fixed state in the axial direction.

Each of the first screw portions 5 is composed of raw material supply portions 7a and 8a formed of flights with a small lead, and cross-conducting portions 7b and 8b formed of flights with a large lead, and each of the screw shafts 7 and 8, tapered portions 7c and 8c are formed between the screw portions 5 and 6, which constitute different diameter portions at positions where the outer diameter changes.

An inner wall tapered portion 1e is formed at the inner wall position of each shaft hole 1b and IC corresponding to the tapered portions 7C and 8c in the cylinder 1, and between each of these tapered portions 7c and 8c and the inner wall tapered portion 1e. , a gap [1 is formed.

Therefore, in the above-described configuration, the cylinder is variably moved in the axial direction during continuous operation so that the gap 1. By changing the kneading parts 7b and 8b of each screw part 5 and 6,
By changing the filling rate within the tank and also changing the residence time,
The degree of kneading of the raw materials was controlled.

[Problems to be Solved by the Invention] Since the conventional twin-screw different diameter kneading extruder was configured as described above, it had the following problems.

That is, the flow resistance (pressure loss) of the raw material (resin) is created by adjusting only the gap mentioned above, but in this case, as shown in FIG. The formula for calculating the pressure loss of flowing raw material (resin) is:
For a simplified analogy, consider that it flows in a parallel plate. However, ΔP = resistance value μ = resin viscosity Q = amount of resin passing W - passing width L = passing length tl = gap through which the resin passes (1), but since the gap t changes by the third power, it is necessary to accurately and finely adjust the relative position between the cylinder 1 and each screw shaft 7 and 8. and 8cO The taper angle is made small so that the change in the gap t1 is minimized even if the cylinder 1 moves a large amount, but this gap 1. and taper part 7
The relationship between the angle θ of e and 8c is as shown in Fig. 6, t1=sinθXχ (cylinder movement amount)...(2)
Therefore, with a limited distance between two axes, it is usually 15°.
This was the limit.

Therefore, as shown in FIG. 3, when looking at the portion where the cylinder movement amount χ is small, the gap 1. The degree of change in the relationship between the resistance value ΔP and the cylinder movement amount χ is extremely significant, such as changes in thermal expansion of the cylinder 1 that occur when the cylinder 1 is switched from heating to cooling. It is extremely difficult to appropriately adjust the movement of the cylinder 1, and the range of adjustment is also limited.

Furthermore, when you want something with a high degree of kneading, try to minimize the gap LL.
However, since the taper portions 7c and 8c come into contact with the cylinder 1, a mechanical stopper must be provided to maintain the minimum gap t1.

Therefore, when high kneading is required, there is also the problem that the high kneading screw must be replaced with a specially manufactured high kneading screw.

The present invention has been made in order to solve the above-mentioned problems, and in particular, it makes it possible to widely and easily adjust the degree of kneading (the degree of squeezing) associated with the movement of the cylinder, and also allows for continuous operation. An object of the present invention is to provide a kneading extruder with two screws of different diameters, which facilitates the axial movement of cylinders therein.

[Means for Solving the Problems] The twin-screw different diameter kneading extruder according to the present invention includes a pair of screw shafts rotatably provided in a cylinder movable in the axial direction, and each of the screw shafts. A first screw part and a second screw part formed through a tapered part and having different outer diameters, and an inner wall tapered part formed on the inner wall of the cylinder corresponding to the tapered part,
The structure includes a cylindrical portion formed adjacent to the tapered portion, and an inner wall cylindrical portion formed adjacent to the inner wall tapered portion.

[Function] In the twin-screw different diameter kneading extruder according to the present invention, a cylindrical part is provided adjacent to the tapered part of the screw shaft, and the material resistance (resin resistance) of the cylindrical part is equal to the raw material resistance (resin resistance) of the tapered part. By adding resistance), it is possible to achieve higher kneading effects and a wider range of adjustment than before, and the relationship between the cylinder movement amount and resistance value is configured so that it is not as sensitive as before, so it is possible to mix with relatively low precision adjustment. The degree can be easily adjusted.

In other words, according to the above-mentioned equation (1), the gap t is effective to the third power, but the length of the flow through it is proportional to the first power, so by changing the relative position of the cylinder and the screw shaft, the cylindrical part can be The effective length over which the inner wall cylinder overlaps is the resistance value, and since this is a first power change, A shown in Fig. 3
As shown by and B, the variation characteristic of the resistance value ΔP with respect to the cylinder movement amount χ has a much gentler slope than the conventional one.

Therefore, when the cylinder is moved to the right in the state shown in Fig. 1, the tapered part, that is, the gap t1, opens in the direction and the resistance decreases, and at the same time, the effective length of the cylindrical part also contracts, and the resistance decreases. By continuously forming the cylindrical part and the tapered part adjacent to each other, one resistance can be added.
This allows the curve of change in the resistance value P to the cylinder movement amount χ to be significantly gentler.

[Example] Hereinafter, preferred examples of the twin-screw different diameter kneading extruder according to the present invention will be described in detail with reference to the drawings.

Note that the same or equivalent parts as in the conventional example will be described using the same reference numerals.

Figures 1 to 3 are for showing a twin-shaft, different-diameter kneading extruder according to the present invention. Enlarged sectional view showing part 3
The figure is a characteristic diagram of resistance value.

In the figure, a cylinder designated by reference numeral 1 is a cylinder that is movable in the axial direction by a hydraulic cylinder 3 provided in the main body 2. Inside this cylinder 1, there is a large diameter cylinder consisting of two shaft holes. A pair of second shaft holes 1b and an IC are continuously formed, each consisting of two small diameter shaft holes partitioned by a first shaft hole 1a and a wall 1f.

The rear end 1d of the cylinder 1 is configured to be able to come into contact with a stopper portion 2a formed on the main body 2, and the rear end 1d of the cylinder 1
The moving distance in the axial direction is measured by a dial gauge 4 disposed in contact with the rear end 1d.

Inside the shaft holes 1a to 1c, a pair of first screw shafts 7 and second screw shafts 8, which are integrally provided with a first screw portion 5 and a second screw portion 6 having different outer diameters, are rotated in a state in which they are pressed against each other. Each of the screw shafts 7 and 8 is connected to a speed reduction mechanism 9 via a connecting shaft 10, and is fixed in the axial direction.

Each of the first screw parts 5 is composed of raw material supply parts 7a and 8a formed of flights with a small lead, and kneading parts 7b and 8b formed of flights with a large lead, and each of the screw shafts 7 and 8, tapered parts 7c and 8c and cylindrical parts 7e and 8e, which constitute different diameter parts at positions where the outer diameter changes, are formed adjacent to and continuous with each other. .

An inner wall tapered portion 1e is formed at the inner wall position of each of the shaft holes 1b and 1c corresponding to the tapered portions 7c and 8c in the cylinder 1, and an inner wall tapered portion 1e is formed between each of these tapered portions 7c and 8c and the inner wall tapered portion 1e. A gap L1 is formed.

Further, inner wall cylindrical portions 11+a and lea
A gap t2 is formed between each of the columnar parts 7e and 8e and each inner wall cylinder part IL+a and lca, and as shown in FIG. 2, effective lengths are formed that overlap each other. has been done.

The twin-screw different diameter kneading extruder according to the present invention is constructed as described above, and its operation will be explained below.

First, by driving the speed reduction mechanism 9, each screw shaft 7 and 8
When the resin raw material is supplied to the raw material supply parts 7a and 8a in the cylinder 1 under the condition that the resin raw materials are supplied to the raw material supply parts 7a and 8a in the cylinder 1 under the condition that the resin raw materials are meshed with each other and rotate based on a predetermined rotation speed, the cross wire parts 7b and 8b
The mixture is kneaded and extruded to the outside through gaps t1 and t2 through a pressurization section 11 (extrusion section) constituted by each second screw section 6 and each shaft hole 1b and 1c.

When adjusting the kneading degree of the resin raw materials in the kneading parts 7b and 8b in the previous state 4, the cylinder 1 is moved in the axial direction by the hydraulic cylinder 3, and the size of the two gaps t and the size of the cylindrical parts 7e and 8e are adjusted. This can be done arbitrarily by changing the effective length between the inner wall cylindrical portions 1ha and lca.

That is, in the present invention, by adding the resin resistance of the cylindrical portions 7e and 8e to the resin resistance of the tapered portions 7C and 8c, it is possible to achieve a higher cross-talk effect and a wider range of adjustment than in the past, and to adjust the cylinder movement amount χ and resistance. The relationship between the values ΔP is no longer as sensitive to change as in the past, and the degree of kneading can be adjusted with relatively low precision.

In other words, according to the above equation (1), the gap 1. is effective to the third power, but the length of the flow there is proportional to the first power. Therefore, by changing the relative position of the cylinder 1 and each screw shaft 7 and 8, the cylindrical parts 7e and 8e and the inner wall cylindrical part The effective length where 1ha and lca overlap each other is the resistance value,
Since this is a first power change, the resistance value ΔP with respect to the cylinder movement amount χ is shown by the A and 8 curves shown in FIG.
It is clear that the change characteristic of is much gentler than the conventional characteristic.

Therefore, when the cylinder 1 is moved to the right in the state shown in FIG. The effective length of the columnar parts 7e and 8e also decreases, and the resistance also decreases. Therefore, by continuously forming the columnar parts 7e and 8C and the tapered parts 7c and 8c adjacent to each other, the resistance value can be added. Therefore, the change curve of the resistance value ΔP with respect to the cylinder movement 1χ can be made much gentler.

Therefore, the moving operation of the cylinder 1 does not require extremely high precision as in the conventional case, and by moving the cylinder 1 using a rough mechanism, an arbitrary degree of kneading can be easily obtained.

Also, the gap t between the curves A and Aa shown in FIG.
2 shows the case where the gap t is set smaller than the gap t in the curves B and Ba.

In addition, in the above-mentioned state, by moving cylinder 1 to the right,
Gap 1. We have described the state in which the effective lengths of the cylindrical portions 7e and 8e are reduced at the same time as they are opened, but contrary to the above, by moving the cylinder 1 to the left, the gap 1. In addition, the effective length of the cylindrical portions 7e and 8e can be increased.

[Effects of the Invention] Since the twin-screw different diameter kneading extruder according to the present invention is configured as described above, it is possible to obtain the following effect.

In other words, in addition to the conventional gap structure using a tapered part, a cylindrical part corresponding to the inner wall cylindrical part formed in the cylinder is continuously formed, so that the degree of change in raw material resistance (resin resistance) with respect to the cylinder movement amount is reduced. can be made much gentler, making it extremely easy to obtain high kneading control (squeezing effect) and a wide cross-mixing range.

Since the degree of change in raw material resistance <m fat resistance) with respect to the amount of cylinder movement is gradual, the accuracy of cylinder movement can be improved with an extremely rough configuration and adjustment operation, and the degree of kneading can be greatly adjusted during continuous operation. It becomes easier.

[Brief explanation of the drawing]

Figures 1 to 3 are for showing the twin-screw different diameter kneading extruder according to the present invention. Figure 1 is a sectional view showing the overall configuration, and Figure 2 is an enlarged view of the main parts of Figure 1. 3 is a cross-sectional view, and FIG. 3 is a characteristic diagram showing the degree of change in resistance value with respect to the amount of cylinder movement between the conventional structure and the structure of the present invention. FIGS. 4 is a sectional view showing the overall structure, and FIGS. 5 and 6 are operation explanatory diagrams showing the principle of operation of the main parts of FIG. 4. 1 is a cylinder, 1e is an inner wall tapered portion, lba. lea is an inner wall cylinder part, 5 is a first screw part, 6 is a second screw part, 7 is a first screw shaft, 8 is a second screw shaft, 7
c and 8c are tapered portions, 7e and 8e are cylindrical portions, tl is a gap, and D is an effective length.

Claims (1)

[Claims] A pair of screw shafts (7, 8) are rotatably provided in a cylinder (1) that is movable in the axial direction, and each of the screw shafts (7, 8) has a tapered portion (7c, 8c). A first screw portion (5) formed through the screw portion and having different outer diameters from each other.
and the second screw part (6), and the tapered part (7c, 8
In a kneading extruder with two screws having different diameters, the inner wall tapered part (1e) is formed on the inner wall of the cylinder (1) corresponding to c), and the inner wall tapered part (1e) is formed adjacent to the tapered part (7c, 8c). The cylindrical portions (7e, 8e) and the inner wall tapered portion (
Inner wall cylinder portions (1ba, 1ca) formed adjacent to 1e)
), and as the cylinder (1) moves in the axial direction,
The gap (t_1) between the tapered part (7c, 8c) and the inner wall tapered part (1e) is made variable, and the effective gap formed by polymerization between the columnar part (7e, 8e) and the inner wall cylindrical part (1ba, 1ca) is made variable. A kneading extruder with two screws of different diameters, characterized in that the length (D) is made variable.