Sealed mixer

Abstract

In this sealed mixer: a ratio of a length (LW) in an axial direction of a long blade tip surface (401A) of a long blade (401) to a length (LS) in the axial direction of a rotor body (400) is 0.63 or more and less than 1.0; a length in the rotation direction of the long blade (401) is 1 / 2 or more of a length in the rotation direction (F) of the rotor body (400); a clearance ratio of the long blade tip surface (401A) is set between 0.01 and 0.02 (both inclusive); in a rotational phase in which the long blades (401) of a pair of kneading rotors (4) are closest to each other, the ratio of a lapping amount (R) to an inter-rotor gap (∆X) of the pair of kneading rotors (4) is greater than 0.65; and either a middle blade (402) or a short blade (403) is twisted in the direction opposite to the long blade (401), with the twisting angle being set to be greater than 49 degrees.

Description

Closed kneader

[0001] The present invention relates to a closed kneader.

[0002] Conventionally, a closed kneader for kneading kneaded materials such as rubber and plastic together with various additives is known. In Patent Document 1, as such a closed kneader, one having a chamber and a pair of kneading rotors is disclosed. The chamber forms a kneading chamber, and the pair of kneading rotors are arranged side by side in the kneading chamber in the width direction of the closed kneader and rotate in opposite directions to each other. Each of the pair of kneading rotors has three blades. When the pair of kneading rotors rotate and the blades of both kneading rotors repeatedly approach and separate from each other in the width direction, pressure is applied to the kneaded material existing in the space surrounded by the blades of both kneading rotors.

[0003] Japanese Patent Application Laid-Open No. 2010-247412

[0004] The technique described in Patent Document 1 aims at a closed kneader excellent in both fluidity performance and shear performance, but there is a problem in that technique that the kneading effect and kneading energy given to the kneaded material are not sufficient.

[0005] An object of the present invention is made in view of the above problems, and to provide a closed kneader capable of sufficiently giving a kneading effect and kneading energy to the kneaded material.

[0006] The present invention provides a closed-type kneader comprising: a kneading chamber having a sealed space formed inside; and a pair of kneading rotors arranged in the sealed space so as to be parallel to each other along the axial direction and rotating in opposite directions to knead the material to be kneaded into the sealed space. Each of the pair of kneading rotors has a cylindrical rotor body and long blades, medium blades, and short blades arranged on the surface of the rotor body so as to be twisted with respect to the axial direction. The long blade has a tip surface facing the inner circumferential surface of the kneading chamber and having a predetermined width along the rotational direction of the kneading rotor, and a pair of inclined surfaces extending inclined toward the surface of the rotor body from the rear end and front end of the tip surface in the rotational direction, respectively, wherein the ratio of the length of the tip surface of the long blade in the axial direction to the length of the rotor body in the axial direction is 0.63 or more and less than 1.0, the length of the long blade in the rotational direction is 1 / 2 or more of the length of the surface of the rotor body in the rotational direction, and the ratio of the radial gap between the inner circumferential surface and the tip surface to the inner diameter of the inner circumferential surface. The clearance ratio is set to 0.01 or more and 0.02 or less, and in the rotational phase when the long blades of the pair of kneading rotors are closest to each other, if the gap between the pair of kneading rotors, which is the gap between the pair of kneading rotors on the straight line connecting the central axes of the pair of kneading rotors, is ΔX, and the overlap amount, which is the amount of overlap between the pair of kneading rotors in a direction parallel to the straight line, is R / ΔX greater than 0.65, and in the unfolded view of the kneading rotor unfolded in the rotational direction, one of the medium blades and the short blades is twisted in the opposite direction to the long blade, and the twist angle of the said blade with respect to the axial direction is set to be greater than 49 degrees.

[0007] According to the inventors of this invention, when the length of the long blades in the rotational direction is less than half the length of the rotor body, the discharge volume, which is an indicator of mixing and distribution performance, decreases sharply, but when it is half or more, the amount of change can be maintained gradually. In this way, by increasing the length of the long blades in the rotational direction, the kneading energy increases and the ability to take the material into the kneading chamber can be improved. On the other hand, in this case, there is a concern that the effective capacity in the sealed space will decrease in proportion to the volume of the long blades. However, the inventors have found that the ratio of the energy increase to the axial length increase of the long blades is small when the axial long blade ratio is less than 0.63 and large when it is 0.63 or more. For this reason, by setting the axial long blade ratio to 0.63 or more, it can be used in a range in which the rate of increase in kneading energy is large.

[0008] Furthermore, if the clearance between the mixing rotor and the inner surface of the chamber is too small, localized heating may occur due to the rotation of the mixing rotor. Conversely, if the clearance is too large, shear force may not act sufficiently on the material being mixed, making it difficult to transfer mixing energy to the material. Therefore, setting the clearance ratio within the range described above can solve these problems.

[0009] Furthermore, at the cross-sectional position where the ends of the long blades of a pair of kneading rotors are close together, reducing the gap between the two rotors and increasing the overlap amount between the two rotors, that is, setting R / ΔX to greater than 0.65, the material to be kneaded flowing along the long blades is temporarily blocked at their ends, increasing the pressure on the material to be kneaded and improving the ability to grip. As a result, the kneading energy increases, making it possible to stably knead even materials that are difficult to knead.

[0010] Figure 1 is a cross-sectional view of a closed-type kneader according to one embodiment of the present invention. Figure 2A is an unfolded view of the first kneading rotor of a closed-type kneader according to one embodiment of the present invention. Figure 2B is an unfolded view of the second kneading rotor of a closed-type kneader according to one embodiment of the present invention. Figure 3 is a cross-sectional view of a pair of kneading rotors of a closed-type kneader according to one embodiment of the present invention. Figure 4 is a graph showing the maximum pressure (ratio) and intake index when the wrap amount / rotor clearance ratio is changed in a closed-type kneader according to one embodiment of the present invention. Figure 5 is a graph showing the relationship between the axial blade ratio and the energy given to the material to be kneaded in a closed-type kneader according to one embodiment of the present invention. Figure 6 is a graph showing the relationship between the axial blade ratio and Δ energy / Δ axial blade ratio in a closed-type kneader according to one embodiment of the present invention. Figure 7 is a graph showing the relationship between the rotational blade ratio and the discharge amount in a closed-type kneader according to one embodiment of the present invention. Figure 8 is an unfolded view of the first kneading rotor of a closed-type kneader according to a modified embodiment of the present invention.

[0011] Hereinafter, a kneader 1 (corresponding to a closed-type kneader) according to one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a cross-sectional view of the kneader 1 according to this embodiment. In Figure 1, the vertical direction is indicated by arrow V, and the width direction perpendicular to the vertical direction is indicated by arrow W. However, these directions are shown for illustrative purposes only and do not limit the usage mode, structure, etc., of the kneader 1.

[0012] The kneader 1 according to this embodiment is a batch-type kneader that performs kneading by repeatedly carrying out a series of steps from introducing the material to be kneaded, kneading the material to be kneaded, and removing the material to be kneaded. The material to be kneaded is a polymer material such as rubber. Additives such as silica may also be added to the material to be kneaded. In Figure 1, the kneader 1 comprises a kneading chamber 2 (corresponding to a sealed space), a chamber 3 (corresponding to a kneading chamber, also called a casing), a pair of kneading rotors 4, an input section 5, a hopper 6, a ram 7, a cylinder 8, a piston 9, a piston rod 10, and a drop door 11.

[0013] The mixing chamber 2 is a space for mixing the material to be mixed. Therefore, the mixing chamber 2 houses a pair of mixing rotors 4 and receives the material to be mixed.

[0014] Chamber 3 is made of a metal material, has the kneading chamber 2 formed inside, and constitutes the main body of the kneader 1. Chamber 3 has a partition wall 30, which defines the kneading chamber 2. More specifically, the partition wall 30 is connected to the ram 7 and the drop door 11 and defines the kneading chamber 2, which is a cylindrical sealed space. The cylindrical sealed space has a cross-sectional shape that includes two circles. A material supply port for supplying the material to be kneaded is formed at the top of Chamber 3, and a material discharge port for discharging the kneaded material is formed at the bottom of Chamber 3.

[0015] A pair of kneading rotors 4 are arranged in the kneading chamber 2 so as to be parallel to each other along the axial direction, and as shown in Figure 1, they rotate in opposite directions to knead the material to be kneaded into the kneading chamber 2. The pair of kneading rotors 4 include a first kneading rotor 41 and a second kneading rotor 42. In this embodiment, the first kneading rotor 41 and the second kneading rotor 42 are so-called three-blade rotors. The first kneading rotor 41 and the second kneading rotor 42 rotate in opposite directions to each other when viewed from the axial direction to knead the material to be kneaded into the kneading chamber 2. That is, the first kneading rotor 41 rotates in a first rotation direction F, and the second kneading rotor 42 rotates in a second rotation direction F'.

[0016] The input section 5 is openable and closable, allowing the material to be kneaded to be introduced into the chamber 3 through the input section 5.

[0017] The hopper 6 is connected to the material supply port at the top of the chamber 3 and guides the material to be kneaded from the input section 5 to the kneading chamber 2.

[0018] As described above, the ram 7, together with the partition wall 30, defines the kneading chamber 2. The ram 7 can also move up and down together with the piston rod 10, which will be described later.

[0019] Cylinder 8 is, for example, a pneumatic cylinder. In other words, the kneader 1 shown in Figure 1 has an air ram structure.

[0020] The piston 9 can move up and down inside the cylinder 8. The upper end of the piston rod 10 is connected to the piston 9, and the lower end of the piston rod 10 is connected to the ram 7.

[0021] The drop door 11 is made of metal and functions as a lid that closes the material discharge port of the chamber 3. The drop door 11 is positioned to move up and down; when the material discharge port is opened, the drop door 11 descends, and when the material discharge port is closed, the drop door 11 rises.

[0022] In Figure 1, a hydraulic weight structure may be used instead of the air ram structure. In this case, the piston 9 is located above the hopper 6 and replaced by a connecting beam. On the outside of the hopper 6, as an example, a pair of hydraulic cylinders (not shown) are mounted. Each hydraulic cylinder has a cylinder body located outside the hopper 6 and a piston that can move up and down within the cylinder body by hydraulic pressure. Furthermore, the piston and the connecting beam are connected by a piston rod (not shown) that extends in the vertical direction. When the piston moves upward in response to hydraulic pressure, driving force is transmitted to the piston rod, connecting beam, and rod 10, causing the ram 7 to move upward. On the other hand, when the piston moves downward, driving force is transmitted to the piston rod, connecting beam, and rod 10, causing the ram 7 to move downward. Thus, various configurations can be adopted for the drive structure of the ram 7 in the kneader 1.

[0023] Figure 2A is an unfolded view of the first kneading rotor 41 of the kneader 1 according to this embodiment. Figure 2B is an unfolded view of the second kneading rotor 42 of the kneader 1 according to this embodiment. These unfolded views correspond to the rotors unfolded along their rotational directions F and F'. That is, the upper and lower ends of each unfolded view are connected to form a roughly cylindrical kneading rotor 4.

[0024] Referring to Figure 2A, the first kneading rotor 41 has a rotor body 400, a long blade 401, a medium blade 402, and a short blade 403.

[0025] The rotor body 400 is cylindrical in shape and constitutes the main body of the first kneading rotor 41. Shaft portions (not shown) are arranged at both ends (sides) of the rotor body 400 in the axial direction. The first kneading rotor 41 is made rotatable by pivoting these shaft portions on bearings (not shown) provided in the chamber 3. The long blades 401, medium blades 402, and short blades 403 are arranged on the surface of the rotor body 400 so as to be twisted with respect to the axial direction of the first kneading rotor 41. These blades protrude radially outward from the surface of the rotor body 400.

[0026] The long blade 401 is formed in a straight line in the unfolded view of the surface of the first kneading rotor 41, and as shown in Figure 2A, the long blade 401 is formed to extend from the lower right to the upper left.

[0027] The long blade 401 has a long blade tip surface 401A (tip surface) and long blade inclined surfaces 401B and 401C (a pair of inclined surfaces) (see Figure 3). The long blade tip surface 401A is also called the tip surface and faces the inner circumferential surface of the chamber 3. The long blade tip surface 401A has a predetermined width along the rotation direction F of the first kneading rotor 41. In Figure 2A, the long blade tip surface 401A is shown as a solid parallelogram. The center line along the twist direction (longitudinal direction) of the long blade tip surface 401A is shown as a dashed line. The long blade inclined surface 401B extends inclined toward the surface of the rotor body 400 from the front end of the long blade tip surface 401A in the rotation direction F of the first kneading rotor 41 (Figure 3). Similarly, the long blade slope 401C extends inclined toward the surface of the rotor body 400 from the rear end of the long blade tip surface 401A in the rotational direction F of the first kneading rotor 41 (Figure 3). In the cross-sectional view shown in Figure 3, the base ends of the long blade slopes 401B and 401C may be erected at a predetermined angle from the surface of the rotor body 400, or they may extend tangentially from the surface of the rotor body 400. When each slope extends tangentially to the rotor body 400, the point of contact between the virtual outer circle of the cylindrical rotor body 400 and each slope corresponds to the base end of each slope (boundary with the rotor body 400).

[0028] Furthermore, in this embodiment, the entire long wing 401 has a parallelogram shape in the unfolded view, and both the axial end and the other end of the long wing 401 extend along the rotation direction F. In addition, both of these ends are positioned at an inward spacing in the axial direction relative to both ends of the rotor body 400. In this embodiment, the long wing 401 is positioned in the axial center of the rotor body 400, and the distance to both ends of the rotor body 400 is set to be the same. Furthermore, the angle between the axial direction of the first kneading rotor 41 and the direction in which the long wing 401 extends is defined as θ1.

[0029] The intermediate blade 402 is a blade whose length on the rotor body 400 is shorter than that of the long blade 401. As shown in Figure 2A, the intermediate blade 402 is located on the rear side in the rotational direction F relative to the long blade 401, and is positioned at one end in the axial direction (left side in Figure 2A). Similar to the long blade 401, the intermediate blade 402 is formed in a straight line in the unfolded view of the surface of the first kneading rotor 41, and as shown in Figure 2A, it is formed to extend from the lower right to the upper left.

[0030] The intermediate blade 402 has an intermediate blade tip surface 402A. The intermediate blade tip surface 402A has a predetermined width along the rotation direction F of the first kneading rotor 41. In Figure 2A, the center line of the intermediate blade tip surface 402A is shown by a dashed line. The intermediate blade 402, like the long blade 401, has slopes on the rear and front sides of the intermediate blade tip surface 402A in the rotation direction F. Furthermore, an unillustrated blade root located on the front side of the intermediate blade 402 in the rotation direction F is positioned to overlap in the axial direction with an unillustrated blade root located on the rear side of the long blade 401 in the rotation direction F. The angle between the axial direction of the first kneading rotor 41 and the direction in which the intermediate blade 402 extends is defined as θ2.

[0031] The short blade 403 is a blade whose length on the rotor body 400 is shorter than that of the long blade 401 and the medium blade 402. As shown in Figure 2A, the medium blade 402 is located on the rear side in the rotational direction F relative to the long blade 401, and on the other end side in the axial direction (right side in Figure 2A). Similar to the long blade 401, the short blade 403 is formed in a straight line in the unfolded view of the surface of the first kneading rotor 41, and as shown in Figure 2A, it is formed to extend from the lower left to the upper right.

[0032] The short blade 403 has a short blade tip surface 403A. The short blade tip surface 403A has a predetermined width along the rotation direction F of the first kneading rotor 41. In Figure 2A, the center line of the short blade tip surface 403A is shown by a dashed line. The short blade 403, like the long blades 401 and 402, has slopes on the rear and front sides of the short blade tip surface 403A in the rotation direction F. Furthermore, the front portion of the short blade 403 in the rotation direction F is positioned to overlap axially with the rear portion of the medium blade 402 in the rotation direction F. The angle between the axial direction of the first kneading rotor 41 (center line of the first kneading rotor 41) and the direction in which the short blade 403 extends is defined as θ3.

[0033] As shown in Figure 2B, the second kneading rotor 42 has substantially the same structure as the first kneading rotor 41. The second kneading rotor 42 has a rotor body 400, a long blade 401, a medium blade 402, and a short blade 403. For the second kneading rotor 42, the same reference numerals are used for components and parts that have the same shape and function as the first kneading rotor 41. As shown in Figure 2B, in the second kneading rotor 42, the long blade 401 is formed to extend from the upper left to the lower right, the medium blade 402 is formed to extend from the upper left to the lower right, and the short blade 403 is formed to extend from the upper right to the lower left.

[0034] Figure 3 is a cross-sectional view of a pair of kneading rotors 4 of the kneader 1 according to this embodiment. Figure 3 is a cross-sectional view including the end faces of the long blades 401 of the first kneading rotor 41 and the second kneading rotor 42. That is, Figure 3 corresponds to the cross-sectional view at the position indicated by arrow K in Figures 2A and 2B.

[0035] As shown in Figure 3, the first kneading rotor 41 and the second kneading rotor 42 rotate so that their long blades 401 face each other. In the rotational phase in which the long blades 401 of the pair of kneading rotors 4 are closest to each other, as shown in Figure 3, the gap between the pair of kneading rotors 4 on the straight line SL connecting the center points (41S, 42S) of the pair of kneading rotors 4 is defined as the rotor gap ΔX. The amount of overlap of the pair of kneading rotors 4 in the direction parallel to the straight line SL is defined as the overlap amount R. In other words, the distance in the direction parallel to the straight line SL between the rear end (maximum outer diameter portion 401T1) in the rotational direction F of the long blade tip surface 401A of the first kneading rotor 41 and the front end (maximum outer diameter portion 401T2) in the rotational direction F' of the long blade tip surface 401A of the second kneading rotor 42 corresponds to the overlap amount R. This overlap amount R is maximum in the rotational phase shown in Figure 3. In this embodiment, the rotational phases of the first kneading rotor 41 and the second kneading rotor 42, and the shapes of each long blade 401 are set so that R / ΔX is greater than 0.65. The first kneading rotor 41 and the second kneading rotor 42 have the same diameter and length and rotate at the same rotational speed. Conversely, the distance between the front end of the long blade tip surface 401A of the first kneading rotor 41 in the direction of rotation F and the rear end of the long blade tip surface 401A of the second kneading rotor 42 in the direction of rotation F', in a direction parallel to the straight line SL, may correspond to the amount of overlap R.

[0036] As described above, the rotation of the first kneading rotor 41 and the second kneading rotor 42, each having three blades, applies a shear force to the material being kneaded as it passes through the clearance. The clearance is also called the tip clearance and is the gap between the tip surface of each kneading blade and the inner circumferential surface of the chamber 3. In Figure 1, the size of this gap is indicated by h. Furthermore, since each kneading blade is formed in a helical shape with respect to the axial direction, the rotation of the two kneading rotors 4 creates an axial flow in the material being kneaded. In this embodiment, the pair of kneading rotors 4 are interlocking rotors. In other words, when the pair of kneading rotors 4 are mounted in the chamber 3, the outer diameter (maximum outer diameter) of each kneading rotor 4 is greater than the distance between the axes of each kneading rotor 4 (distance between rotors).

[0037] As the first kneading rotor 41 and the second kneading rotor 42 rotate, the following movements (meshing) occur sequentially. Specifically, the middle blades 402 and short blades 403 of the first kneading rotor 41 repeatedly move closer to and away from the long blades 401 of the second kneading rotor 42 in the rotation direction F. Also, the middle blades 402 and short blades 403 of the second kneading rotor 42 repeatedly move closer to and away from the long blades 401 of the first kneading rotor 41 in the rotation direction F'. Furthermore, the rear end of the long blades 401 of the first kneading rotor 41 in the rotation direction F and the front end of the long blades 401 of the second kneading rotor 42 in the rotation direction F' repeatedly move closer to and away from each other. Furthermore, the rear end of the long blade 401 of the second kneading rotor 42 in the rotational direction F' and the front end of the long blade 401 of the first kneading rotor 41 in the rotational direction F repeatedly move closer together and further apart.

[0038] While techniques for kneading materials using a pair of kneading rotors (especially meshing rotors) have been known for some time, it has been difficult to ensure the gripping ability of materials such as rubber, increase the pressure applied to the material to improve cohesiveness, and furthermore, provide sufficient kneading energy to the material. The inventors of the present invention have repeatedly conducted thorough studies on the shape of the kneading rotor and have succeeded in obtaining a kneading rotor 4 that can effectively solve the above problems.

[0039] In other words, the aforementioned pair of kneading rotors 4 (first kneading rotor 41, second kneading rotor 42) have the following characteristics. The shape of the kneading rotors 4 will be explained using the first kneading rotor 41 as an example. The effects brought about by these characteristics will be described in detail in the embodiments below.

[0040] In the first kneading rotor 41, the ratio of the axial length LW of the tip surface 401A of the long blade 401 to the axial length LS of the rotor body 400 (also called the axial blade ratio) is 0.63 or more and less than 1.0. Also, the length of the long blade 401 (including the tip surface 401A, the inclined surface 401B, and the inclined surface 401C) in the rotational direction F is half or more of the length of the surface of the rotor body 400 in the rotational direction F. Furthermore, the clearance ratio, which is the ratio of the radial gap h between the inner surface of the chamber 3 and the tip surface 401A to the inner diameter D of the inner surface of the chamber 3 surrounding the first kneading rotor 41, is set to 0.01 or more and 0.02 or less. As shown in Figure 3, in the rotational phase when the long blades 401 of the pair of kneading rotors 4 are closest to each other, if the gap between the pair of kneading rotors 4 on the straight line SL connecting the central axes of the pair of kneading rotors 4 is ΔX, and the overlap amount of the pair of kneading rotors 4 in the direction parallel to the straight line SL is R, then R / ΔX is set to be greater than 0.65. Also, in the unfolded view of the first kneading rotor 41 in the rotational direction F, the short blades 403 are twisted in the opposite direction to the long blades 401, and the twist angle θ3 of the short blades 403 with respect to the axial direction is set to be greater than 49 degrees.

[0041] Regarding the long blades 401, if the length of the long blades 401 in the rotation direction F is less than half the length of the rotor body 400, the discharge amount of the mixing and distribution performance index decreases sharply. However, if it is half or more, the change becomes gradual, so it is desirable to set it to half or more.

[0042] Furthermore, increasing the length of the long blades 401 in the rotational direction increases the kneading energy and improves the ability to incorporate the material into the kneading chamber 2. On the other hand, in this case, there is a concern that the effective capacity in the kneading chamber 2 will decrease in proportion to the volume of the long blades 401. However, the inventors have found that the ratio of the energy increase to the axial length increase of the long blades 401 is small when the axial long blade ratio is less than 0.63, and large when it is 0.63 or greater. Therefore, by setting the aforementioned axial long blade ratio to 0.63 or greater, it is possible to use the device in a range where the rate of increase in kneading energy is large.

[0043] Incidentally, in order to stably exhibit such an effect, if the clearance between the kneading rotor 4 and the inner peripheral surface of the chamber 3 is too small, partial heat generation may occur. If the clearance is too large, the shear may not act sufficiently, and it may be difficult to apply kneading energy to the material. Also, regarding the length of the tip surface 401A (chip portion) of the long blade 401 of the long blade in the rotational direction F, if it is too short, the generation of shear force becomes insufficient, and since it is too far apart in the closest phase from the long blade 401 (maximum outer diameter portion 401T) of the second kneading rotor 42 on the other side, the generation of pressure in that portion becomes insufficient, and it has been found that there is a possibility that kneading energy cannot be secured. For this reason, as described above, by defining the structure and positional relationship of the pair of kneading rotors 4, the above problems have been solved.

[0044] Also, as shown in FIG. 3, at the cross-sectional position where the ends of the long blades 401 of the pair of kneading rotors 4 are close to each other, the gap between the two rotors is reduced and the lap amount of the two rotors is increased. That is, by setting R / ΔX to be greater than 0.65, the kneaded material flowing along the long blade 401 is temporarily blocked at its end, and the pressure of the kneaded material increases, so the bite property is improved. As a result, it has been found that the kneading energy also increases, and it becomes possible to knead even materials that are difficult to wrap.

[0045] It is desirable that the R / ΔX is set to 0.87 or less.

[0046] According to such a configuration, the average of the ratio of the gap and the lap with respect to the standard becomes large, which is advantageous for the take-in property of the kneaded material. As a result, while maintaining the maximum pressure ratio in a high region, the take-in performance of the kneaded material can also be maintained at a high level.

[0047] Further, due to the improvement in the above-mentioned lumpability, it is not necessary to specifically increase the pressing force (ram pressure) of the ram 7 for pressing the kneaded material from above, and it is also possible to reduce the force for pressing a sealing material (not shown) provided between the surrounding members. As a result, the effect that the mechanical life of the kneader 1 is prolonged can also be obtained.

[0048] With the above characteristics, a kneading rotor 4 suitable for materials with low cohesiveness, such as a rubber composition containing a large amount of silica, for example, is realized.

[0049] In addition, in the present embodiment, the short blades 403 are twisted in the opposite direction to the long blades 401, thereby forming a confluence point of the flow of the kneaded material. Further, by setting the twist angle (angle θ3) of the short blades 403 to 49 degrees or more, the kneaded material flowing through the long blades 401 can be reversed in the opposite direction, and a more active flow can be obtained. As a result, it is possible to prevent the kneaded material from staying between the long blades 401 of the pair of kneading rotors 4. Further, the cycle in which the unknit material reaches the high-pressure portion becomes shorter, and the kneading time is shortened. Therefore, when kneading the same production amount, the mechanical life per unit production weight becomes longer.

[0050] In addition, in the present embodiment, the length d (FIG. 2A) in the rotation direction F of the center line of the long blade tip surface 401A of the long blade 401 is set to be 3 / 10 or more of the length G in the rotation direction F of the surface of the rotor body 400.

[0051] According to such a configuration, when the length in the rotation direction of the center line along the twist direction of the long blade tip surface 401A of the long blade 401 is 3 / 10 or more of the length in the rotation direction F of the surface of the rotor body 400, a large length in the rotation direction F of the blade tip portion that applies a high shear stress to the kneaded material can be ensured. Therefore, the shear force and the pressure can be improved.

[0052] Furthermore, in the present embodiment, the ratio of the length of the long blade 401 to the length of the short blade 403 in the axial direction is set to be 2.2 or more.

[0053] As mentioned above, if the ratio of the long blade 401 to the short blade 403 is kept at 0.63 or higher, if the ratio of the lengths of the long blade 401 to the short blade 403 in the axial direction is too small, in other words, if the short blade 403 is too long, the flow of the material to be kneaded may be obstructed, and smooth movement of the material to be kneaded within the kneading chamber 2 may not be achieved. In this case, the volume within the kneading chamber 2 will be reduced, and a sufficient amount of kneading may not be achieved. Therefore, by setting the ratio of the length of the long blade 401 to the length of the short blade 403 in the axial direction to 2.2 or higher, problems caused by the length relationship between the long blade 401 and the short blade 403 can be further resolved.

[0054] Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

[0055] Figure 4 is a graph showing the maximum pressure (ratio) and intake performance index when the overlap amount / rotor clearance ratio is changed in the kneader 1 according to the above embodiment. The overlap amount / rotor clearance ratio (R / ΔX) on the horizontal axis of Figure 4 can be expressed as R / ΔX, as described above using Figure 3, when ΔX is the gap between the pair of kneading rotors 4 on the straight line SL connecting the center points of the pair of kneading rotors 4 at the rotational phase in which the long blades 401 of the pair of kneading rotors 4 are closest to each other, and R is the overlap amount of the pair of kneading rotors 4 in a direction parallel to the straight line SL. The intake performance index is the average of the ratio of the clearance to the standard clearance and the ratio of the reciprocal of the wrap to the reciprocal of the standard overlap, and can be defined by the following formula: Intake performance index: [(ΔX / ΔX0) + {(1 / R) / (1 / R0)}] / 2 Here, ΔX0 and R0 represent their respective standard values. The standard state defined here is for standardization purposes, so any numerical value may be used. However, in this embodiment, the condition in which R / ΔX is maximized among the conditions under which numerical analysis was performed (the data on the far right of Figure 4) is adopted.

[0056] In this embodiment, the characteristics of each case when the shape of the mixing rotor 4 is changed were calculated using numerical analysis. Specifically, equations 1, 2, and 4 below are the governing equations of the fluid analysis used in this analysis. Thus, in this embodiment, the three-dimensional continuity equation, the momentum conservation equation, and the energy conservation equation were used. In this embodiment, gravity is considered as an external force term in the equations. Furthermore, a known fluid flow analysis software based on the finite difference method was used for the numerical analysis simulation. In addition, in this embodiment, the behavior of the gas-liquid interface is reproduced using fluid analysis in order to evaluate the behavior of the gas-liquid interface. As a model for this gas-liquid interface, the VOF method, which considers only the liquid phase as the free surface, is used. The equation corresponding to this model is shown below as equation 3.

[0057]

[0058]

[0059]

[0060]

[0061] Here, u, T, ρ, t, p, η, g, Cp, and λ in the above equations represent the velocity vector, temperature, density, time, pressure, viscosity, gravitational acceleration, specific heat, and thermal conductivity of each calculation cell, respectively. Q in equation 4 is the exothermic term, which is treated here as the kneading energy.

[0062] Furthermore, F in Equation 3 represents the liquid phase fraction of each calculation cell. Therefore, F = 0: void cell, 0 < F < 1: interface cell, and F = 1: fluid cell. In this numerical analysis, the energy conservation equation was treated as an advection-diffusion term for the exothermic term (energy) by adjusting the specific heat so that the product of density and specific heat in the energy conservation equation is 1.

[0063] In the formula, ρ, t, η, g, Cp, and λ correspond to known input values. On the other hand, the values ​​u, T, and p correspond to output values ​​calculated by numerical analysis.

[0064] Next, let's explain the maximum pressure (ratio) on the left vertical axis of Figure 4. This maximum pressure (ratio) is the ratio of the numerical data obtained from the numerical analysis (simulation) described above to the standard pressure, and represents the pressure under each condition. The standard pressure defined here is for standardization purposes, so any value can be used, but in Figure 4, the pressure at the condition where R / ΔX is maximized among the conditions under which the numerical analysis was performed (the data at the far right of Figure 4) is adopted. It can be said that the higher this maximum pressure (ratio), the more advantageous it is for the cohesiveness of the material being kneaded.

[0065] Next, we will explain the intake efficiency index on the right vertical axis of Figure 4. First, we consider the effect of securing an intake area for taking in the material to be kneaded as a result of changing the space between the pair of kneading rotors 4. In this case, a larger rotor gap ΔX is desirable, and a smaller overlap amount R makes intake easier. Therefore, by taking the reciprocal of R, it is possible to evaluate it so that the effect increases when the value is large, similar to the rotor gap ΔX. Accordingly, in this embodiment, half of the sum of ΔX and 1 / R is used as the intake efficiency index as one of the evaluation indicators. This index represents the ease with which the space between the rotors is secured and the material to be kneaded is easily taken into the kneading chamber 2 from above to below. In this case, since the magnitudes of R and ΔX are different, their influence on the evaluation index is different, so they are converted to ratios to the values ​​of each parameter under predetermined conditions (normalized), and the evaluation is performed using the average value.

[0066] As mentioned above, widening the distance between the axes of the pair of kneading rotors 4 secures space between the rotors, which is advantageous for material intake. On the other hand, since the long blades 401 come into contact with the material to be kneaded and form a flow path for the material to be kneaded, if the shape of the long blades 401 has too much overlap, it creates resistance to the flow, and the material intake function of the blades decreases. In this embodiment, in order to evaluate the effects of these conflicting phenomena at the same dimension, we newly discovered that the reciprocal of the overlap amount and the increase in the gap amount are first normalized as ratios from the standard position, and then the average of the two is taken. A larger average value indicates a greater intake function, so it is desirable to set the parameters of the pair of kneading rotors 4 in the region where this index is large. On the other hand, if this average value is small, the maximum pressure between the rotors decreases and the cohesiveness also decreases. Therefore, by using the above index, it is possible to set the optimal conditions while considering multiple effects.

[0067] Referring to Figure 4, which evaluates the characteristics described above, in the cross-sectional shape (Figure 3) where the ends of the long blades 401 of both kneading rotors 4 are close together, setting the ratio of the overlap amount R to the gap ΔX between the two rotors (R / ΔX) to 0.65 or more increases the material pressure after the material to be kneaded flows into the ends of the long blades 401. As a result, the gripping of the material to be kneaded also improves, increasing the kneading energy while improving cohesiveness. Furthermore, it becomes possible to reduce the ram pressure that presses down on the material to be kneaded from above, reducing the mechanical load and extending the lifespan of sealing materials and other mechanical parts.

[0068] As mentioned above, if the ratio of the long blade 401 to the short blade 403 is kept at 0.63 or higher, if the ratio of the axial lengths of the long blade 401 to the short blade 403 is too small, in other words, if the short blade 403 is too long, the flow of the material to be kneaded may be obstructed, and smooth movement of the material to be kneaded within the kneading chamber 2 may not be achieved. Also, if the ratio of the axial lengths of the long blade 401 to the short blade 403 is too small, in other words, if the short blade 403 is too long, the volume within the kneading chamber 2 will be reduced, and a sufficient amount of kneading may not be achieved. Therefore, by setting the ratio of the length of the long blade 401 to the length of the short blade 403 in the axial direction to 2.2 or higher, these problems caused by the length relationship between the long blade 401 and the short blade 403 can be further resolved.

[0069] As shown in Figure 4, in the region where the ratio of the overlap amount R to the gap ΔX between the two rotors (R / ΔX) is 0.87 or higher, the maximum pressure (ratio) does not increase. Furthermore, it can be seen that a smaller R / ΔX results in a larger intake index, which is advantageous for the intake of the material to be kneaded. As a result, it is more desirable to set R / ΔX in the range of 0.65 to 0.87. In this region, the maximum pressure (ratio) is sufficiently secured, and the intake of the material to be kneaded is also secured. Therefore, the effect of shortening the kneading time can be obtained, and it is also possible to reduce the wear per unit of production of surrounding sealing members, etc.

[0070] Figure 5 is a graph showing the relationship between the axial blade length ratio and energy in the kneader 1 according to the previous embodiment. Figure 6 is a graph showing the relationship between the axial blade length ratio and Δ energy / Δ axial blade length ratio in the kneader 1 according to the previous embodiment. The axial blade length ratio on the horizontal axis in Figures 5 and 6 corresponds to the ratio (LW / LS) of the axial length LW of the blade tip surface 401A of the blade 401 to the axial length LS of the rotor body 400, as described above. Here, the kneading energy (hereinafter also referred to as energy) when this axial blade length ratio is increased from 55% was calculated by the numerical analysis described above. That is, Q in Equation 4 above corresponds to the energy in Figures 5 and 6.

[0071] Due to the structure of the mixing chamber 2 and the pair of mixing rotors 4, lengthening the long blades 401 allows more energy to be transferred to the material being mixed by drawing it into the mixing chamber 2 and increasing the mixing area. However, this also has the disadvantage of reducing the capacity of the mixing chamber 2 to accept the material being mixed. Therefore, by setting the axial long blade ratio to 63% or more, the proportion of energy transferred increases, allowing for mixing within an advantageous range while mitigating the above disadvantage.

[0072] Specifically, as shown in Figures 5 and 6, increasing the axial blade length ratio increases the rate of energy increase due to the increased material intake and gripping capacity. In particular, using the blade in the region beyond the boundary of an axial blade length ratio of 62%, indicated by the dashed line in Figure 6, yields a high level of effectiveness. Furthermore, increasing the axial blade length ratio to 63% or higher yields a more stable effect. Thus, increasing the axial blade length ratio tends to increase energy, and the effect of energy increase is particularly significant when the axial blade length ratio is 0.63 or higher.

[0073] Figure 7 is a graph showing the relationship between the ratio of blade length in the rotational direction and the discharge rate in a kneader 1 according to one embodiment of the present invention. Here, the method for calculating the discharge rate on the vertical axis of Figure 7 will be explained. In this embodiment, a known extrusion theory formula is adopted as the discharge rate. This extrusion theory formula is shown in Equation 5 below. Furthermore, α, β, and γ in Equation 5 are shown in Equations 6, 7, and 8, respectively.

[0074]

[0075]

[0076]

[0077]

[0078] In the above equations, the parameters Y represent the discharge rate, N the rotational speed, ΔP the pressure, and μ the shear viscosity. D is the average diameter of the mixing rotor 4, k is the groove depth, j is the lead length, LS is the length of the mixing rotor 4, ψ is the swing angle (twist angle relative to the axis), δ is the clearance, and e is the land width. In the case of a long blade 401, the land width corresponds to the width of the long blade tip surface 401A. More specifically, the land width is the width of the long blade tip surface 401A in the direction perpendicular to the axial direction of the mixing rotor 4 (rotation direction F in Figure 2A). Also, n is the number of blades (= number of rotor blades).

[0079] As shown in Figure 7, in the region where the ratio of the long blades 401 in the rotational direction is 0.5 (1 / 2) or less, the discharge volume, which is an indicator of mixing and distribution performance, decreases sharply. However, at 0.5 or more, the rate of change becomes gradual, and a stable discharge volume can be ensured. In Figure 7, the long blade ratio in the rotational direction of 0.5 or more is set as the region in which a fluctuation range of 10% is maintained relative to the maximum discharge volume near a long blade ratio of 0.6 in the rotational direction. Therefore, sufficient stirring capacity (distribution capacity) can be ensured in this region.

[0080] The above describes a kneader 1 according to one embodiment of the present invention. However, the present invention is not limited to the above-described form. The following modified embodiments are also possible in the present invention.

[0081] (1) In the above embodiment, an example was described in which the first kneading rotor 41 and the second kneading rotor 42 are so-called three-blade rotors, but the number of blades of the first kneading rotor 41 and the second kneading rotor 42 may be increased.

[0082] (2) In the above embodiment, the short blade 403 was described in an unfolded view of the first kneading rotor 41 in the rotation direction F, where the short blade 403 was twisted in the opposite direction to the long blade 401, and the twist angle θ3 of the short blade 403 with respect to the axial direction was set to be greater than 49 degrees. In a modified embodiment, instead of the short blade 403, the middle blade 402 may be twisted in the opposite direction to the long blade 401. In this case as well, it is desirable that the twist angle θ2 of the middle blade 402 with respect to the axial direction is set to be greater than 49 degrees.

[0083] (3) Figure 8 is an unfolded view of the first kneading rotor 41 of the kneader 1 according to a modified embodiment of the present invention. In this modified embodiment, the outer diameter of each of the long blade 401, medium blade 402, and short blade 403 is set such that the clearance ratio changes along the direction in which each blade extends. The clearance ratio is set in the range of 0.01 to 0.02.

[0084] With this configuration, different clearances can be provided by partially changing the clearance ratio in one of the blades. As a result, appropriate shear can be applied to materials ranging from soft to hard as the mixing rotor 4 rotates. Furthermore, the flow of the material being mixed in the mixing chamber 2 can be made more complex, thereby increasing the mixing capacity.

[0085] In this modified embodiment, the tip surface 401A of the long wing 401 has a first tip surface S, a second tip surface M, and a third tip surface L. The first tip surface S is located at the rear end in the rotation direction F of the long wing tip surface 401A. At the first tip surface S, the gap h with the inner circumferential surface of the chamber 3 is set to a first gap. The second tip surface M is located at the front end in the rotation direction F of the long wing tip surface 401A. At the second tip surface M, the gap h with the inner circumferential surface of the chamber 3 is set to a second gap which is larger than the first gap. The third tip surface L is located between the first tip surface S and the second tip surface M of the long wing tip surface 401A. At the third tip surface L, the gap h with the inner circumferential surface of the chamber 3 is set to a third gap which is larger than the second gap. Furthermore, each end face is labeled with the initial letters Large, Middle, or Small, according to the size of the gap h, and enclosed in a square. The same applies hereafter. As an example, the clearance ratios for the first gap, second gap, and third gap are set to 0.01, 0.015, and 0.02, respectively. In addition, the axial width of each end face is set to satisfy the relationship L > M > S.

[0086] With this configuration, by arranging the first tip surface S and the second tip surface M at both ends of the long blade 401, a further pressure improvement effect can be expected when the long blades of both rotors are in close proximity. Alternatively, both ends of the long blade 401 may also be designated as the second tip surface M.

[0087] The first tip surface S, the second tip surface M, and the third tip surface L are separated from each other by a boundary extending along the rotational direction F, with a step difference between them.

[0088] With this configuration, each tip surface can be easily and accurately positioned on the tip surface 401A of the long wing.

[0089] On the other hand, the tip surface 402A of the mid-wing 402 has a fourth tip surface S and a fifth tip surface M. The fourth tip surface S is located at the rear end in the rotation direction F of the mid-wing tip surface 402A. At the fourth tip surface S, the gap h with the inner circumferential surface of the chamber 3 is set to the fourth gap. The fifth tip surface M is located at the front end in the rotation direction F of the mid-wing tip surface 402A. At the fifth tip surface M, the gap h with the inner circumferential surface of the chamber 3 is set to the fifth gap, which is larger than the fourth gap. Note that the fourth gap may be the same size as the first gap. Also, the fifth gap may be the same size as the second gap.

[0090] Furthermore, the tip surface 403A of the short wing 403 has a sixth tip surface L and a seventh tip surface M. The sixth tip surface L is located at the rear end in the rotation direction F of the short wing tip surface 403A. At the sixth tip surface L, the gap h with the inner circumferential surface of the chamber 3 is set to the sixth gap. The seventh tip surface M is located at the front end in the rotation direction F of the short wing tip surface 403A. At the seventh tip surface M, the gap h with the inner circumferential surface of the chamber 3 is set to the seventh gap, which is smaller than the sixth gap. Note that the sixth gap may be the same size as the third gap. Also, the seventh gap may be the same size as the second gap.

[0091] As shown in Figure 8, when viewed along the rotational direction F, the first tip surface S of the long wing 401 is located in front of the sixth tip surface L of the short wing 403 in the rotational direction. Similarly, the second tip surface M of the long wing 401 is located in front of the fourth tip surface S of the middle wing 402 in the rotational direction.

[0092] In other words, in the configuration shown in Figure 8, in the region through which different wings pass in the axial direction, the first tip surface S that forms a small clearance and the third tip surface L that forms a large clearance are visited in sequence in the region through which the long wing and the short wing pass. In the region through which the long wing 401 and the medium wing 402 pass, the combination is the second tip surface M of the long wing 401 and the fourth tip surface S of the medium wing 402. On the other hand, in the region through which only one wing passes, only the second tip surface M that forms an intermediate size clearance passes. In the region through which only the long wing passes, the third tip surface L is used. As a result, it is prevented that only large clearances pass along the axial direction, which would otherwise worsen the overall flow.

[0093] Furthermore, if the clearance is kept constant throughout the entire kneading rotor 4, the shear force applied to the material will differ between soft and hard materials. For example, in the case of soft materials, the shear force is small, so sufficient kneading energy may not be supplied. Conversely, in the case of hard materials, a larger clearance allows for easier flow, preventing localized heat generation due to excessive shear. Also, although the meshing rotor has a spatially narrow shape and its overall mixing capacity due to flow is inferior to that of a tangential rotor in some respects, the creation of complex flows by providing different clearances as described above outweighs this limitation in mixing capacity. Therefore, due to the effects brought about by the different clearances, the material that has become cohesive under the increased pressure between the pair of kneading rotors 4 is less likely to remain in the same place in the kneading chamber 2 and is more likely to move to other locations. As the material that has not yet cohesive is frequently moved to areas of high pressure, kneading can be performed more quickly overall, reducing mechanical load and extending the lifespan of seals and other wear components.

[0094] Furthermore, the outer diameter of at least one of the long wing 401, the medium wing 402, and the short wing 403 may be set such that the clearance ratio changes along the direction in which the at least one wing extends.

[0095] Furthermore, the changes in clearance on each wing are not limited to being set in steps. The changes in clearance may be continuous. Also, different clearances may be set in four or more regions on a single wing.

[0096] Furthermore, although the above embodiments were described in which the short wing 403 extends in different directions from the long wing 401 and the medium wing 402, it is also possible for the long wing 401 and the short wing 403 to extend in the same direction, while the medium wing 402 extends in a different direction.

[0097] Furthermore, although the above embodiments have described a configuration in which the long blades 401 are arranged in the central part of the rotor body 400 in the axial direction, the long blades 401 may also be distributed unevenly to one end or the other end of the rotor body 400 in the axial direction.

[0098] Furthermore, in the above modified embodiment, the clearance ratio was described as being set in the range of 0.01 or more and 0.02 or less for all wings. However, if the clearance ratio of at least one wing (or the clearance ratio of a part of its region) falls within the range of 0.01 or more and 0.02 or less, the clearance ratios of the other wings may be set to less than 0.01 or greater than 0.02.

[0099] Furthermore, in the above embodiments, the long wingtip surface 401A was described as being a parallelogram, as shown by the solid line in Figure 2A, for example. However, the present invention is not limited thereto, and the following modifications may be applied. (Example 1) The wingtip may be cut, for example, a shape in which at least a part of the corner of the parallelogram is cut. In this case, the angle and direction of the cut are not limited. Also, the location of the corner to be cut is not limited (it may be one corner or both corners). (Example 2) The front / rear / both sides of the wing in the direction of rotation (the sides of the parallelogram in the example of Figure 2A) may be bent in the middle instead of being straight. In this case, the bent shape may be either concave or convex relative to the wing (the same applies to Example 3 below). Furthermore, as a result of having a bent shape, the land width of the wingtip may be different on the front and rear sides in the direction of rotation (the same applies to Example 3 below). (Example 3) The front / rear / both sides of the wing in the direction of rotation (the sides of the parallelogram in the example of Figure 2A) may be curved instead of being straight. (Example 4) At least two of the above examples 1, 2, and 3 may be combined.

[0100] Furthermore, the wing shapes described above are not limited to long wings; similar modifications can be applied to short wings and mid-wing designs as well.

[0101] The specific embodiments described above mainly include inventions having the following configurations.

[0102] The present invention provides a closed-type kneader comprising: a kneading chamber having a sealed space formed inside; and a pair of kneading rotors arranged in the sealed space so as to be parallel to each other along the axial direction and rotating in opposite directions to knead the material to be kneaded into the sealed space. Each of the pair of kneading rotors has a cylindrical rotor body and long blades, medium blades, and short blades arranged on the surface of the rotor body so as to be twisted with respect to the axial direction. The long blade has a tip surface facing the inner circumferential surface of the kneading chamber and having a predetermined width along the rotational direction of the kneading rotor, and a pair of inclined surfaces extending inclined toward the surface of the rotor body from the rear end and front end of the tip surface in the rotational direction, respectively, wherein the ratio of the length of the tip surface of the long blade in the axial direction to the length of the rotor body in the axial direction is 0.63 or more and less than 1.0, the length of the long blade in the rotational direction is 1 / 2 or more of the length of the surface of the rotor body in the rotational direction, and the ratio of the radial gap between the inner circumferential surface and the tip surface to the inner diameter of the inner circumferential surface. The clearance ratio is set to 0.01 or more and 0.02 or less, and in the rotational phase when the long blades of the pair of kneading rotors are closest to each other, if the gap between the pair of kneading rotors, which is the gap between the pair of kneading rotors on the straight line connecting the central axes of the pair of kneading rotors, is ΔX, and the overlap amount, which is the amount of overlap between the pair of kneading rotors in a direction parallel to the straight line, is R / ΔX greater than 0.65, and in the unfolded view of the kneading rotor unfolded in the rotational direction, one of the medium blades and the short blades is twisted in the opposite direction to the long blade, and the twist angle of the said blade with respect to the axial direction is set to be greater than 49 degrees.

[0103] According to the inventors of this invention, when the length of the long blades in the rotational direction is less than half the length of the rotor body, the discharge volume, which is an indicator of mixing and distribution performance, decreases sharply, but when it is half or more, the amount of change can be maintained gradually. In this way, by increasing the length of the long blades in the rotational direction, the kneading energy increases and the ability to take the material into the kneading chamber can be improved. On the other hand, in this case, there is a concern that the effective capacity in the sealed space will decrease in proportion to the volume of the long blades. However, the inventors have found that the ratio of the energy increase to the axial length increase of the long blades is small when the axial long blade ratio is less than 0.63 and large when it is 0.63 or more. For this reason, by setting the axial long blade ratio to 0.63 or more, it can be used in a range in which the rate of increase in kneading energy is large.

[0104] Furthermore, if the clearance between the mixing rotor and the inner surface of the chamber is too small, localized heating may occur due to the rotation of the mixing rotor. Conversely, if the clearance is too large, shear force may not act sufficiently on the material being mixed, making it difficult to transfer mixing energy to the material. Therefore, setting the clearance ratio within the range described above can solve these problems.

[0105] Furthermore, at the cross-sectional position where the ends of the long blades of a pair of kneading rotors are close together, reducing the gap between the two rotors and increasing the overlap amount between the two rotors, that is, setting R / ΔX to greater than 0.65, the material to be kneaded flowing along the long blades is temporarily blocked at their ends, increasing the pressure on the material to be kneaded and improving the ability to grip. As a result, the kneading energy increases, making it possible to stably knead even materials that are difficult to knead.

[0106] In the above configuration, the R / ΔX may be set to 0.87 or less.

[0107] This configuration allows for maintaining a high maximum pressure ratio while also maintaining high performance in incorporating the material to be kneaded.

[0108] In the above configuration, the length of the center line along the twist direction of the tip surface of the long blade in the direction of rotation may be set to 3 / 10 or more of the length of the surface of the rotor body in the direction of rotation.

[0109] According to this configuration, if the length of the center line in the rotational direction along the torsional direction of the tip surface of the long blade is set to 3 / 10 or more of the length of the rotor body surface in the same rotational direction, a large length in the rotational direction of the blade tip portion that applies high shear stress to the kneaded material can be secured, thereby improving shear force and pressure.

[0110] In the above configuration, the ratio of the length of the long wing to the length of the short wing in the axial direction may be set to 2.2 or more.

[0111] When the aforementioned axial ratio of long blades to short blades is ensured to be 0.63 or higher, if the ratio of long blade to short blade lengths in the axial direction is too small, in other words, if the short blades are too long, the flow of the material to be kneaded may be obstructed, and smooth movement of the material to be kneaded within the enclosed space may not be achieved. In this case, the volume within the enclosed space will also be reduced, and a sufficient amount of kneading may not be achieved. As in this configuration, by setting the ratio of the length of long blades to the length of short blades in the axial direction to 2.2 or higher, these problems caused by the length relationship between long and short blades can be further resolved.

[0112] In the above configuration, the outer diameter of at least one of the long wing, the medium wing, and the short wing may be set such that the clearance ratio changes along the direction in which the at least one wing extends.

[0113] This configuration allows a single blade to have different clearances by partially changing the clearance ratio of one blade. As a result, appropriate shear can be applied to materials ranging from soft to hard as the mixing rotor rotates. Furthermore, it can complicate the flow of the material being mixed within the enclosed space, thereby increasing the mixing capacity.

[0114] In the above configuration, the tip surface of the long wing may have a first tip surface located at the rear end in the direction of rotation, with a gap between it and the inner circumferential surface of the kneading chamber set to a first gap; a second tip surface located at the front end in the direction of rotation, with a gap between it and the inner circumferential surface of the kneading chamber set to a second gap that is larger than the first gap; and a third tip surface located between the first tip surface and the second tip surface, with a gap between it and the inner circumferential surface of the kneading chamber set to a third gap that is larger than the second gap.

[0115] According to this configuration, by arranging a first tip surface and a second tip surface at both ends of the long blade, further pressure can be applied to the material being kneaded during the phase when the long blades of both rotors are in close proximity.

[0116] In the above configuration, the first tip surface, the second tip surface, and the third tip surface may be separated from each other by a boundary extending along the direction of rotation, with a step difference between them.

[0117] This configuration allows for easy and precise placement of each tip surface on the long wing.

[0118] According to the present invention, it is possible to provide a closed-type kneader that can sufficiently impart kneading effect and kneading energy to the material to be kneaded.

Claims

1. A closed-type kneader comprising: a kneading chamber having a sealed space formed inside; and a pair of kneading rotors arranged in the sealed space so as to be parallel to the axial direction and rotating in opposite directions to knead the material to be kneaded into the sealed space, wherein each of the pair of kneading rotors has: a cylindrical rotor body; and long blades, medium blades, and short blades arranged on the surface of the rotor body so as to be twisted with respect to the axial direction; the long blade has a tip surface facing the inner circumferential surface of the kneading chamber and having a predetermined width along the rotational direction of the kneading rotor; and a pair of inclined surfaces extending inclined toward the surface of the rotor body from the rear end and front end of the tip surface in the rotational direction, respectively, wherein the ratio of the length of the tip surface of the long blade in the axial direction to the length of the rotor body in the axial direction is 0.63 or more and less than 1.0; and the length of the long blade in the rotational direction is 1 / 2 or more of the length of the surface of the rotor body in the rotational direction. A closed-type kneader, wherein the clearance ratio, which is the ratio of the radial gap between the inner circumferential surface and the tip surface to the inner diameter of the inner circumferential surface, is set to 0.01 or more and 0.02 or less; in the rotational phase when the long blades of the pair of kneading rotors are closest together, if the gap between the pair of kneading rotors is ΔX, which is the gap between the pair of kneading rotors on a straight line connecting the central axes of the pair of kneading rotors, and the overlap amount R is the amount of overlap between the pair of kneading rotors in a direction parallel to the straight line, then R / ΔX is set to be greater than 0.65; and in an unfolded view of the kneading rotor unfolded in the rotational direction, one of the medium blades and the short blades is twisted in the opposite direction to the long blade, and the twist angle of the one blade with respect to the axial direction is set to be greater than 49 degrees.

2. The closed-type kneader according to claim 1, wherein the R / ΔX is set to 0.87 or less.

3. The closed-type kneader according to claim 1, wherein the length in the rotational direction of the center line along the torsional direction of the tip surface of the long wing is set to be 3 / 10 or more of the length of the surface of the rotor body in the rotational direction.

4. The closed-type kneader according to claim 1, wherein the ratio of the length of the long wing to the length of the short wing in the axial direction is set to 2.2 or more.

5. The closed-type kneader according to claim 1, wherein the outer diameter of at least one of the long wing, the medium wing, and the short wing is set such that the clearance ratio changes along the direction in which the at least one wing extends.

6. The closed-type kneader according to claim 5, wherein the tip surface of the long wing has: a first tip surface located at the rear end in the direction of rotation, with the gap between it and the inner circumferential surface of the kneading chamber set to a first gap; a second tip surface located at the front end in the direction of rotation, with the gap between it and the inner circumferential surface of the kneading chamber set to a second gap that is larger than the first gap; and a third tip surface located between the first tip surface and the second tip surface, with the gap between it and the inner circumferential surface of the kneading chamber set to a third gap that is larger than the second gap.

7. The sealed kneader according to claim 6, wherein the first tip surface, the second tip surface, and the third tip surface are separated from each other by a boundary extending along the direction of rotation, with a step difference between them.

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