Sealed kneader and kneading rotor for sealed kneader

Abstract

A sealed kneader includes a kneading chamber in which a sealed space is formed and a first kneading rotor and a second kneading rotor that rotate in opposite directions to knead a material to be kneaded. Each of the first kneading rotor and the second kneading rotor has a first blade, a second blade and a third blade shorter than the first blade, a fourth blade, and a fifth blade and a sixth blade shorter than the fourth blade. Among the first kneading rotors, the first blade, the second blade, and the third blade are disposed on one end side in the axial direction of the kneading chamber, and the fourth blade, the fifth blade, and the sixth blade are disposed on the other end side in the axial direction of the kneading chamber. Among the second kneading rotors, the fourth blade, the fifth blade, and the sixth blade are disposed on the one end side, and the first blade, the second blade, and the third blade are disposed on the other end side.

Description

Internal mixer and mixing rotor for internal mixer

[0001] The present invention relates to an internal mixer and a mixing rotor for an internal mixer.

[0002] Conventionally, there has been known a closed-type kneading machine that kneads materials to be kneaded, such as rubber and plastic, together with various additives. Patent Document 1 discloses such a closed-type kneading machine having a chamber and a pair of kneading rotors. The chamber forms a kneading chamber, and the pair of kneading rotors are arranged side by side in the width direction of the closed-type kneading machine and rotate in opposite directions. Each of the pair of kneading rotors has three blades. As the pair of kneading rotors rotate, the blades of both kneading rotors repeatedly move toward and away from each other in the width direction, thereby applying pressure to the material to be kneaded in the space surrounded by the blades of both kneading rotors.

[0003] The technology described in Patent Document 1 has a problem in that it is difficult to apply pressure to the material to be kneaded sufficiently and efficiently. Therefore, when kneading is performed in a state where the filling rate of the material to be kneaded in the kneading chamber is low, it is difficult to apply energy, and the compressive force between the materials to be kneaded decreases, which may result in insufficient kneading or the material to be kneaded not being sufficiently consolidated. Furthermore, the above problem may also occur when kneading a material to be kneaded and an additive that are set to a compounding ratio that makes it difficult to knead or to consolidate, such as high-performance silica-containing rubber.

[0004] Patent No. 4542605

[0005] An object of the present invention is to provide an internal mixer that can apply sufficient and efficient pressure to the material to be mixed.

[0006] The present invention provides a hermetic mixer comprising: a kneading chamber having a sealed space formed therein; and a first kneading rotor and a second kneading rotor disposed in the sealed space so as to face each other in the width direction of the kneading chamber and be parallel to an axial direction perpendicular to the width direction, the first kneading rotor and the second kneading rotor rotating in opposite directions to each other to knead a material to be mixed introduced into the sealed space. Each of the first kneading rotor and the second kneading rotor has a first blade extending in a radial direction and a first twisting direction intersecting the axial direction, respectively, second blades and third blades extending in the first twisting direction and having lengths in the axial direction shorter than the lengths of the first blades in the axial direction, a fourth blade extending in a second twisting direction intersecting the radial direction, the axial direction, and the first twisting direction, respectively, and fifth blades and sixth blades extending in the second twisting direction and having lengths in the axial direction shorter than the lengths of the fourth blades in the axial direction. Of the first kneading rotor, the first blade, the second blade, and the third blade are arranged at one end side of the kneading chamber in the axial direction, and the fourth blade, the fifth blade, and the sixth blade are arranged at the other end side of the kneading chamber in the axial direction, and of the second kneading rotor, the fourth blade, the fifth blade, and the sixth blade are arranged at one end side, and the first blade, the second blade, and the third blade are arranged at the other end side.

[0007] The present invention also provides a kneading rotor for a hermetic mixer, the kneading rotor being rotatably disposed in a hermetic space of a hermetic mixer having an internally formed hermetic space. The kneading rotor for a hermetic mixer has a first blade extending in a first twisting direction that intersects a radial direction and an axial direction perpendicular to the radial direction, second and third blades extending in the first twisting direction and having lengths in the axial direction that are shorter than the lengths of the first blades in the axial direction, a fourth blade extending in a second twisting direction that intersects the radial direction, the axial direction, and the first twisting direction, and fifth and sixth blades extending in the second twisting direction and having lengths in the axial direction that are shorter than the lengths of the fourth blades in the axial direction. The first, second, and third blades are disposed at one end in the axial direction, and the fourth, fifth, and sixth blades are disposed at the other end in the axial direction.

[0008] FIG. 1 is a cross-sectional view of a closed-type kneader according to one embodiment of the present invention. FIG. 2 is a plan view of a pair of kneading rotors of a closed-type kneader according to one embodiment of the present invention. FIG. 3 is a development view of a pair of kneading rotors of a closed-type kneader according to one embodiment of the present invention. FIG. 4 is a cross-sectional view of the body of a first kneading rotor of a closed-type kneader according to one embodiment of the present invention. FIG. 5 is a development view obtained by superimposing the development views of FIG. 3 on each other. FIG. 6 is a graph showing the average pressure generated in the chamber of a kneader according to the prior art and the average pressure generated in the chamber of a kneader according to the present invention. FIG. 7 is a graph showing the cooling performance of a kneader according to the prior art and the cooling performance of a kneader according to the present invention. FIG. 8 is a graph showing the relationship between pressure and integrated volume fraction. FIG. 9 is a graph showing the kneading energy of a kneader according to the prior art and the kneading energy of a kneader according to the present invention.

[0009] A kneader 1 (corresponding to a closed-type kneader) according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of the kneader 1 according to this embodiment. In each drawing, the vertical direction is indicated by arrow V, the width direction perpendicular to the vertical direction is indicated by arrow W, and the axial direction perpendicular to both the vertical direction and the width direction is indicated by arrow A (Fig. 2). However, these directions are shown for the purpose of explanation and do not limit the use mode, structure, etc. of the kneader 1.

[0010] The kneader 1 according to this embodiment is a batch-type kneader that performs kneading by repeatedly performing a series of steps, from feeding 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 polymeric material such as rubber. An additive such as silica is added to the material to be kneaded. In FIG. 1 , the kneader 1 includes a kneading chamber 2 (corresponding to an enclosed space), a chamber 3 (corresponding to a kneading chamber), a pair of kneading rotors 4, a feeding section 5, a hopper 6, a ram 7, a cylinder 8, a piston 9, a piston rod 10, and a drop door 11. The cylinder 8 is, for example, a pneumatic cylinder. However, the cylinder 8 may also be a hydraulic cylinder or the like.

[0011] The kneading chamber 2 is a space for kneading the material to be kneaded. Therefore, the kneading chamber 2 accommodates a pair of kneading rotors 4 and receives the material to be kneaded. The chamber 3 has the kneading chamber 2 therein and constitutes the main body of the kneader 1. The chamber 3 has a partition wall 30, which defines the kneading chamber 2.

[0012] More specifically, the partition wall 30 is connected to the ram 7 and the drop door 11 to define the kneading chamber 2, which is a cylindrical sealed space that is made up of two circles.

[0013] FIG. 2 is a plan view of a pair of kneading rotors 4. As shown in FIG. 2, the pair of kneading rotors 4 are intermeshing rotors arranged adjacent to each other in the width direction (direction indicated by arrow W) of the chamber 3 so that their blades intermesh with each other. When installed in the chamber 3, the axial direction of the pair of kneading rotors 4 coincides with the axial direction of the chamber 3 (direction indicated by arrow A). Note that the axial direction of each of the pair of kneading rotors 4 is perpendicular to the radial direction of body portions 411 and 421 (described later). The axial direction of the chamber 3 is perpendicular to the width direction of the chamber 3. The pair of kneading rotors 4 are rotatably supported in the chamber 3. The pair of kneading rotors 4 includes a first kneading rotor 41 (corresponding to the one kneading rotor) that is one of the pair of kneading rotors 4, and a second kneading rotor 42 (corresponding to the other kneading rotor) that is the other of the pair of kneading rotors 4. The first kneading rotor 41 and the second kneading rotor 42 are arranged in the kneading chamber 2 so as to face each other in the width direction and be parallel to each other in the axial direction. Specifically, on one side in the axial direction A shown in Fig. 2 (corresponding to one axial end side of the chamber 3), ends of the first kneading rotor 41 and the second kneading rotor 42 face each other in the width direction. Also, on the other side in the axial direction A shown in Fig. 2 (corresponding to the other axial end side of the chamber 3), opposite ends of the first kneading rotor 41 and the second kneading rotor 42 face each other in the width direction. The first kneading rotor 41 and the second kneading rotor 42 rotate in opposite directions as viewed in the axial direction, thereby kneading the material to be kneaded introduced into the kneading chamber 2. Specifically, 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'.

[0014] The first kneading rotor 41 is a so-called six-blade rotor and is a rotor for the kneader 1. The first kneading rotor 41 has a rotation shaft 410 (corresponding to the shaft portion), a body portion 411, a first long blade 4111A (corresponding to the first blade), a first intermediate blade 4112A (corresponding to the second blade) ( FIG. 3 ), a second intermediate blade 4113A (corresponding to the third blade), a second long blade 4114A (corresponding to the fourth blade), a first short blade 4115A (corresponding to the fifth blade), and a second short blade 4116A (corresponding to the sixth blade). The rotation shaft 410 has a cylindrical shape and extends along the axial direction. The rotation shaft 410 is supported in the chamber 3 so as to be rotatable along the first rotation direction F, and extends from both ends of the body portion 411. The body portion 411 has a cylindrical shape with an inner diameter larger than the outer diameter of the rotating shaft 410, and is integral with the rotating shaft 410. The body portion 411 also rotates in a first rotation direction F in response to the rotation of the rotating shaft 410. The body portion 411 has a first end face 411a, a second end face 411c, and an outer peripheral surface 411b. The first end face 411a is located at an end of the body portion 411 in the axial direction and is a surface perpendicular to the axial direction. The second end face 411c is located at an end opposite the first end face 411a in the axial direction and is a surface perpendicular to the axial direction. The outer peripheral surface 411b is interposed between both end faces 411a, 411c in the axial direction and forms the radially outer peripheral surface of the body portion 411. The body section 411 supports a first long wing 4111A, a first medium wing 4112A, a second medium wing 4113A, a second long wing 4114A, a first short wing 4115A, and a second short wing 4116A.

[0015] 3 is a development view of a pair of kneading rotors 4, and is a development view of an imaginary cylindrical surface including a land surface described later. As shown in Fig. 3, the first long blade 4111A, first medium blade 4112A, and second medium blade 4113A of the first kneading rotor 41 are arranged on one side in the axial direction A. The second long blade 4114A, first short blade 4115A, and second short blade 4116A are arranged on the other side in the axial direction A.

[0016] The first long wing 4111A, the first medium wing 4112A, and the second medium wing 4113A extend in a first torsional direction (T1 in FIG. 3 ) that intersects the axial direction and the radial direction of the body portion 411. More specifically, the first long wing 4111A, the first medium wing 4112A, and the second medium wing 4113A extend in the first torsional direction from the first end surface 411a of the body portion 411. The axial lengths of the first medium wing 4112A and the second medium wing 4113A are shorter than the axial length of the first long wing 4111A. Furthermore, the second long wing 4114A, the first short wing 4115A, and the second short wing 4116A extend in a second torsional direction (T2 in FIG. 3 ) that intersects the axial direction, the radial direction, and the first torsional direction. Specifically, the second long wing 4114A, the first short wing 4115A, and the second short wing 4116A extend in a second torsional direction from the second end surface 411c of the body 411. The axial lengths of the first short wing 4115A and the second short wing 4116A are shorter than the axial length of the second long wing 4114A.

[0017] 3 , in this embodiment, the first kneading rotor 41 has a first blade, a second blade, and a third blade arranged in this order forward in the direction of rotation of the rotor at one end of the rotor, and a fourth blade, a fifth blade, and a sixth blade arranged in this order forward in the direction of rotation of the rotor at the other end of the rotor. More specifically, at one axial end of the first kneading rotor 41, a first medium blade 4112A and a second medium blade 4113A are arranged in this order from upstream to downstream in the first direction of rotation F, with respect to the first long blade 4111A. Furthermore, at the other axial end of the first kneading rotor 41, a first short blade 4115A and a second short blade 4116A are arranged in this order from upstream to downstream in the first direction of rotation F, with respect to the second long blade 4114A. In the second kneading rotor 42, the first long blade 4211B, the first medium blade 4212B, the second medium blade 4213B, the second long blade 4214B, the first short blade 4215B, and the second short blade 4216B are arranged in the same order. As will be described in detail later, the first long blade 4211B of the second kneading rotor 42 is arranged so as to mesh with the second long blade 4114A and the first short blade 4115A of the first kneading rotor 41. In addition, the first long blade 4111A of the first kneading rotor 41 is arranged so as to mesh with the first short blade 4215B and the second short blade 4216B of the second kneading rotor 42.

[0018] In this embodiment, the first long wing 4111A, the first medium wing 4112A, the second medium wing 4113A, the second long wing 4114A, the first short wing 4115A, and the second short wing 4116A are arranged so that they extend in the same twisting direction and so that a space is formed between adjacent wings in the first rotational direction F.

[0019] In addition, in this embodiment, when the body portion 411 is viewed in any cross section perpendicular to the axial direction, the wings are arranged so that at least one of the above wings is always present.

[0020] Continuing to refer to Figure 3, each of the above-mentioned blades has a land surface, a front slope, and a rear slope. The land surface is located at the outer end of the body portion 411 in the radial direction. The front slope is disposed forward of the land surface in the first rotation direction F of the first kneading rotor 41. The rear slope is disposed rearward of the land surface in the first rotation direction F of the first kneading rotor 41. Specifically, the first long blade 4111A has a first long blade front slope 4111a, a first long blade land surface 4111b, and a first long blade rear slope 4111c. The first medium blade 4112A has a first medium blade front slope 4112a, a first medium blade land surface 4112b, and a first medium blade rear slope 4112c. The second center wing 4113A has a second center wing leading slope 4113a, a second center wing land surface 4113b, and a second center wing trailing slope 4113c. The second long wing 4114A has a second long wing leading slope 4114a, a second long wing land surface 4114b, and a second long wing trailing slope 4114c. The first short wing 4115A has a first short wing leading slope 4115a, a first short wing land surface 4115b, and a first short wing trailing slope 4115c. The second short wing 4116A has a second short wing leading slope 4116a, a second short wing land surface 4116b, and a second short wing trailing slope 4116c.

[0021] The first long wing land surface 4111b, the first intermediate wing land surface 4112b, and the second intermediate wing land surface 4113b extend along a first twist direction (T1 in FIG. 3). Note that "extending along the first twist direction" does not only mean extending strictly parallel to the first twist direction, but also includes extending at a predetermined angle with respect to the first twist direction. The second long wing land surface 4114b, the first short wing land surface 4115b, and the second short wing land surface 4116b extend along a second twist direction (T2 in FIG. 3). Note that "extending along the second twist direction" does not only mean extending strictly parallel to the second twist direction, but also includes extending at a predetermined angle with respect to the second twist direction.

[0022] As shown in Fig. 3 , in this embodiment, the slope of the second long blade 4114A overlaps with the slope of the first long blade 4111A. Specifically, the rear slope 4114c of the second long blade is connected to the front slope 4111a of the first long blade. More specifically, a portion of the rear slope 4114c of the second long blade located near the center in the axial direction (the lower end of the blade extending from the upper left end to the lower right in the developed view of the first kneading rotor 41 in Fig. 3 ) is connected to a portion of the front slope 4111a of the first long blade located near the center in the axial direction (near the upper end of the blade extending from the lower left end to the upper right in the developed view of the first kneading rotor 41 in Fig. 3 ).

[0023] In this embodiment, the length L1 of the first long wing 4111A in the axial direction is set to be equal to or greater than half the length L0 of the body portion 411 in the axial direction. Furthermore, the sum of the length L1 of the first long wing 4111A in the axial direction and the length L4 of the second long wing 4114A in the axial direction is set to be equal to or greater than the length L0 of the body portion 411 in the axial direction. For example, the length L1 of the first long wing 4111A in the axial direction is set to be equal to or greater than half and equal to or less than the length L0 of the body portion 411 in the axial direction, and the length L4 of the second long wing 4114A in the axial direction is set to be equal to or greater than one-fifth and equal to or less than the length L0 of the body portion 411 in the axial direction. However, the upper limit of the sum of the length L1 of the first long wing 4111A in the axial direction and the length L4 of the second long wing 4114A in the axial direction is set to be equal to or less than two times the length L0 of the body portion 411 in the axial direction. Furthermore, the length L2 of the first central wing 4112A and the second central wing 4113A in the axial direction is set to be equal to or greater than one-fifth and less than one-half of the length L0 of the body portion 411 in the axial direction. For example, in this embodiment, the length L2 of the first central wing 4112A and the second central wing 4113A in the axial direction is set to be two-fifths of the length L0 of the body portion 411 in the axial direction. Furthermore, the length L3 of the first short wing 4115A and the second short wing 4116A in the axial direction is set to be equal to or greater than one-tenth and less than one-fifth of the length L0 of the body portion 411 in the axial direction. For example, in this embodiment, the length L3 of the first short wing 4115A and the second short wing 4116A in the axial direction is set to be three-tenths of the length L0 of the body portion 411 in the axial direction.

[0024] Fig. 4 is a cross-sectional view of the body portion 411, including the first long blade 4111A, as viewed from the axial direction. Fig. 4 shows the penetration angle θ1 of the first long blade 4111A. The "penetration angle θ1 of the first long blade 4111A" refers to the acute angle formed by the first tangent TA1 and the second tangent TA2, where C is the circle described by the land surface 4111b of the first long blade as the first mixing rotor 41 rotates, E1 is the boundary point between the front slope 4111a of the first long blade and the land surface 4111b of the first long blade, TA1 is the tangent to the virtual circle C that passes through the first boundary point E1, and TA2 is the tangent to the front slope 4111a of the first long blade that passes through the first boundary point E1. In this embodiment, the angle of intrusion θ1 of the first long blade 4111A is set to be equal to or greater than 10° and equal to or less than 20°. The same applies to the other blades.

[0025] FIG. 4 shows the central angle θ2 relative to the land width of the first long blade land surface 4111b. The "land width of the first long blade land surface 4111b" refers to the length from one end to the other end of the first long blade land surface 4111b in the first rotation direction F. In the example shown in FIG. 4, the first boundary point E1 is the one end, and the second boundary point E2 between the first long blade land surface 4111b and the first long blade rear slope 4111c is the other end. Furthermore, the "central angle θ2 relative to the land width of the first long blade 4111A" refers to the acute angle formed between the line connecting the first boundary point E1 and the axis O of the first kneading rotor 41 and the line connecting the second boundary point E2 and the axis O. In this embodiment, the central angle θ2 relative to the land width of the first long blade land surface 4111b is set to 14° or more. It is more preferable that the land width be set to 18° or more.

[0026] 3, in this embodiment, the twist angle θ3 of each of the first long blade 4111A, first medium blade 4112A, second medium blade 4113A, second long blade 4114A, first short blade 4115A, and second short blade 4116A is set to be 35° or more and 55° or less. The "twist angle θ3" refers to the acute angle formed by an imaginary line extending along the land surface of each blade in the developed view of FIG. 3 and an imaginary line extending along the first rotation direction F of the first kneading rotor 41.

[0027] In this embodiment, the upper limit of the ratio (tip clearance ratio) of the tip clearance, which is the gap between the land surface of each blade and the partition wall 30 of the chamber 3, to the inner diameter of the chamber 3 is set to less than 0.02. The lower limit of the tip clearance may be any mechanical limit.

[0028] The second kneading rotor 42 is a so-called six-blade rotor and is a rotor for the kneader 1. The second kneading rotor 42 corresponds to a rotor obtained by axially inverting the structure of the first kneading rotor 41 and shifting the rotation phase by 180°. A first end face 421a of the second kneading rotor 42 is located on the same plane as a second end face 411c of the first kneading rotor 41. The second end face 421c of the second kneading rotor 42 is located on the same plane as a first end face 411a of the first kneading rotor 41. Since the configuration of the second kneading rotor 42 is generally similar to the configuration of the first kneading rotor 41, a detailed description thereof will be omitted. Note that in each drawing, components of the second kneading rotor 42 that are similar to those of the first kneading rotor 41 are denoted by replacing 41 with 42 in the reference numerals of the first kneading rotor 41. Furthermore, for the first long blade 4111A, the first medium blade 4112A, the second medium blade 4113A, the second long blade 4114A, the first short blade 4115A, and the second short blade 4116A, if the 41 included in the reference numerals is replaced with 42 and the suffix of the reference numerals is replaced with A, then the description of each blade of the second kneading rotor 42 applies. For the slopes and land surfaces of each blade of the first kneading rotor 41, if the 41 included in the reference numerals is replaced with 42, then the description of the slopes and land surfaces of each blade of the second kneading rotor 42 applies.

[0029] <About Blade Interlocking> FIG. 5 is a development in which the developments in FIG. 3 are superimposed on each other. In FIG. 5, the second rotation direction F' of the second kneading rotor 42 is aligned with the first rotation direction F. That is, the development in FIG. 3 of the second kneading rotor 42 is inverted left and right. In FIG. 5, the rotation phase of the second kneading rotor 42 is adjusted from the state shown in FIG. 3. In FIG. 5, the overlapping blades are portions that repeatedly move closer to and further away from each other in the width direction as the pair of kneading rotors 4 rotate. In FIG. 5, the upper side of the portion protruding beyond the right end of the development corresponds to the first long blade rear slope 4211c shown at the left end of the development. The lower side of the portion protruding beyond the right end of the development in FIG. 5 corresponds to the second short blade rear slope 4216c shown at the left end of the development. In FIG. 5, to easily distinguish between the blades, the land surfaces of the blades relating to the first kneading rotor 41 are indicated by solid lines, and the land surfaces of the blades relating to the second kneading rotor 42 are indicated by dashed lines.

[0030] In the blade arrangement according to this embodiment, as the pair of kneading rotors 4 rotate, the first long blade 4111A of the first kneading rotor 41 meshes between the first short blade 4215B and the second short blade 4216B of the second kneading rotor 42. That is, when viewed from the axial direction, the first long blade 4111A of the first kneading rotor 41 is disposed between the first short blade 4215B and the second short blade 4216B of the second kneading rotor 42 in the second rotation direction F'. At this time, the first long blade 4111A does not contact either the first short blade 4215B or the second short blade 4216B. This forms an intermeshing space surrounded by the blades of the first kneading rotor 41 and the second kneading rotor 42. Specifically, a first intermeshing space SP1 is formed surrounded by the first long blade 4111A, the first short blade 4215B, and the second short blade 4216B. 5, the symbol "SP1" is assigned to three locations in the first meshing space SP1: a portion surrounded by the first long blade 4111A and the first short blade 4215B, a portion surrounded by the first long blade 4111A and the second short blade 4216B, and a portion surrounded by the first long blade 4111A and the outer circumferential surface 421b of the second kneading rotor 42. When the pair of kneading rotors 4 rotate, the material to be kneaded present in the first meshing space SP1 is kneaded by the first long blade 4111A, the first short blade 4215B, and the second short blade 4216B, and pressure is applied to the material to be kneaded.

[0031] Furthermore, in the arrangement of the blades according to this embodiment, as the pair of kneading rotors 4 rotate, the first long blade 4211B of the second kneading rotor 42 meshes between the second long blade 4114A and the first short blade 4115A of the first kneading rotor 41. That is, as viewed from the axial direction, the first long blade 4211B of the second kneading rotor 42 is disposed between the second long blade 4114A and the first short blade 4115A of the first kneading rotor 41. This forms a second meshing space SP2 surrounded by the first long blade 4211B, the second long blade 4114A, and the first short blade 4115A. As the pair of kneading rotors 4 rotate, the material to be kneaded present in the second meshing space SP2 is kneaded by the first long blade 4211B, the second long blade 4114A, and the first short blade 4115A, and pressure is applied to the material to be kneaded.

[0032] Furthermore, as the pair of kneading rotors 4 rotate, the second medium blade 4113A of the first kneading rotor 41 meshes between the first short blade 4215B and the second long blade 4214B of the second kneading rotor 42. This forms a third meshing space SP3 surrounded by the second medium blade 4113A, the first short blade 4215B, and the second long blade 4214B. As the pair of kneading rotors 4 rotate, the material to be kneaded present in the third meshing space SP3 is kneaded, and pressure is applied to the material to be kneaded.

[0033] Furthermore, as the pair of kneading rotors 4 rotate, the second medium blade 4213B of the second kneading rotor 42 meshes between the second long blade 4114A and the second short blade 4116A of the first kneading rotor 41. This forms a fourth meshing space SP4 surrounded by the second medium blade 4213B, the second long blade 4114A, and the second short blade 4116A. As the pair of kneading rotors 4 rotate, pressure is applied to the material to be kneaded present in the fourth meshing space SP4.

[0034] Furthermore, as the pair of kneading rotors 4 rotate, the first intermediate blade 4112A of the first kneading rotor 41 meshes between the second long blade 4214B and the second short blade 4216B of the second kneading rotor 42. This forms a fifth meshing space SP5 surrounded by the first intermediate blade 4112A, the second long blade 4214B, and the second short blade 4216B. As the pair of kneading rotors 4 rotate, pressure is applied to the material to be kneaded present in the fifth meshing space SP5.

[0035] Furthermore, as the pair of kneading rotors 4 rotate, the first center blade 4212B of the second kneading rotor 42 meshes between the first short blade 4115A and the second short blade 4116A of the first kneading rotor 41. This forms a sixth meshing space SP6 surrounded by the first center blade 4212B, the first short blade 4115A, and the second short blade 4116A.

[0036] As described above, in this embodiment, the first long blade 4111A (corresponding to the first blade), the first medium blade 4112A (corresponding to the second blade), and the second medium blade 4113A (corresponding to the third blade) are arranged on one side of the axial direction A (corresponding to one end side of the chamber 3 in the axial direction), and the second long blade 4114A (corresponding to the fourth blade), the first short blade 4115A (corresponding to the fifth blade), and the second short blade 4116A (corresponding to the sixth blade) are arranged on the other side of the axial direction A (corresponding to the other end side of the chamber 3 in the axial direction). Furthermore, of the second kneading rotor 42, the second long blade 4214B (corresponding to the fourth blade), the first short blade 4215B (corresponding to the fifth blade), and the second short blade 4216B (corresponding to the sixth blade) are arranged on one side in the axial direction A, and the first long blade 4211B (corresponding to the first blade), the first medium blade 4212B (corresponding to the second blade), and the second medium blade 4213B (corresponding to the third blade) are arranged on the other side in the axial direction A. According to this configuration, as the first kneading rotor 41 and the second kneading rotor 42 rotate, the first long blade 4111A, the first medium blade 4112A, and the second medium blade 4113A of the first kneading rotor 41 repeatedly move close to and away from the second long blade 4214B, the first short blade 4215B, and the second short blade 4216B of the second kneading rotor 42 in the width direction. Furthermore, the second long blade 4114A, the first short blade 4115A, and the second short blade 4116A of the first kneading rotor 41 repeatedly approach and move away from the first long blade 4211B, the first medium blade 4212B, and the second medium blade 4213B of the second kneading rotor 42 in the width direction. In this manner, meshing spaces surrounded by the blades of the first kneading rotor 41 and the second kneading rotor 42 can be formed more frequently than when the first kneading rotor 41 and the second kneading rotor 42 are configured as so-called three-blade rotors having only three blades. Specifically, in this embodiment, the first to sixth meshing spaces SP1 to SP6 can be formed. The material to be kneaded is kneaded in these first to sixth meshing spaces SP1 to SP6, and pressure is applied to the material to be kneaded. This allows pressure to be applied to the material to be kneaded sufficiently and efficiently.

[0037] Furthermore, with the above configuration, pressure can be applied sufficiently and efficiently to the material to be kneaded, improving the cohesiveness of the material to be kneaded. Also, with the above configuration, pressure can be applied sufficiently and efficiently to the material to be kneaded, increasing the kneading energy. Also, with the above configuration, the material to be kneaded can be transferred more easily between the first kneading rotor 41 and the second kneading rotor 42.

[0038] In addition, in this embodiment, the first long blade 4111A of the first kneading rotor 41 and the first short blade 4215B and second short blade 4216B of the second kneading rotor 42 are arranged so that the first long blade 4111A of the first kneading rotor 41 (corresponding to the one kneading rotor), which is one of the first kneading rotor 41 and the second kneading rotor 42, meshes between the first short blade 4215B and the second short blade 4216B of the second kneading rotor 42 (corresponding to the other kneading rotor), which is the other of the first kneading rotor 41 and the second kneading rotor 42, and the first long blade 4211B of the second kneading rotor 42 and the second long blade 4114A and first short blade 4115A of the first kneading rotor 41 are arranged so that the first long blade 4211B of the second kneading rotor 42 meshes between the second long blade 4114A and the first short blade 4115A of the first kneading rotor 41. Therefore, a larger pressure can be applied to the material to be kneaded. As a result, the cohesiveness of the material to be kneaded can be further improved. In addition, the kneading energy is further increased. In addition, the transferability of the material to be kneaded between the first kneading rotor 41 and the second kneading rotor 42 is further improved.

[0039] In this embodiment, the first long blade 4111A, first medium blade 4112A, and second medium blade 4113A of the first kneading rotor 41 extend from the first end face 411a as a base point, and the second long blade 4114A, first short blade 4115A, and second short blade 4116A extend from the second end face 411c as a base point. Also, the first long blade 4211B, first medium blade 4212B, and second medium blade 4213B of the second kneading rotor 42 extend from the first end face 421a as a base point, and the second long blade 4214B, first short blade 4215B, and second short blade 4216B extend from the second end face 421c as a base point. Therefore, the axial length of each blade can be made longer than when each blade extends from a base point located axially away from the corresponding rotor end face. This increases the total length of the blades in the axial direction, thereby increasing the area in which the material to be mixed can be mixed, resulting in a further increase in mixing energy.

[0040] In this embodiment, the second long blade rear slope 4114c of the first mixing rotor 41 is connected to the first long blade front slope 4111a of the first mixing rotor 41. Therefore, the axial length of both wings 4114A and 4111A can be made longer than when the base point of the second long blade 4114A is the second end surface 411c and the base point of the first long blade 4111A is the first end surface 411a, and the length of both wings 4114A and 4111A is set to a length such that the second long blade rear slope 4114c and the first long blade front slope 4111a are not connected. Similarly, in the second mixing rotor 42, the second long blade rear slope 4214c is connected to the first long blade front slope 4211a. Therefore, the axial length of both wings 4214B and 4211B can be made longer. This structure further improves the cohesion of the material to be mixed. Also, the average pressure can be improved by about 20% compared to a case in which the second long blade rear slope 4114c of the first mixing rotor 41 is not connected to the first long blade front slope 4111a and the second long blade rear slope 4214c of the second mixing rotor 42 is not connected to the first long blade front slope 4211a.

[0041] In this embodiment, the length L1 of the first long wing 4111A in the axial direction is set to be equal to or greater than half the length L0 of the body portion 411 in the axial direction, and the sum of the length L1 of the first long wing 4111A in the axial direction and the length L4 of the second long wing 4114A in the axial direction is set to be equal to or greater than 1. Furthermore, the length L2 of the first intermediate wing 4112A and the second intermediate wing 4113A in the axial direction is set to be equal to or greater than one-fifth but less than one-half the length L0 of the body portion 411 in the axial direction. Furthermore, the length L3 of the first short wing 4115A and the second short wing 4116A in the axial direction is set to be equal to or less than one-fifth the length L0 of the body portion 411 in the axial direction. The same applies to the second kneading rotor 42. This configuration improves the transfer of the material to be kneaded between the first kneading rotor 41 and the second kneading rotor 42. That is, pressure and flow are generated effectively, the flow rate of the material to be kneaded moving back and forth between the first kneading rotor 41 and the second kneading rotor 42 increases, and the material to be kneaded can be mixed effectively.

[0042] Furthermore, in this embodiment, when the body portion 411 is viewed in any cross section perpendicular to the axial direction, the blades are arranged so that at least one of the above blades is always present. With this configuration, the length of each blade in the axial direction is ensured. Also, since the total length of each blade in the axial direction is increased, the area in which the material to be kneaded can be kneaded is increased.

[0043] Furthermore, in this embodiment, the blades are arranged so that they extend in the same twisting direction and a space is formed between adjacent blades in the first rotation direction F. This configuration ensures the length of each blade in the axial direction. Also, since the total length of each blade in the axial direction is increased, the area in which the material to be kneaded can be kneaded is increased.

[0044] Furthermore, in this embodiment, the upper limit of the ratio (tip clearance ratio) of the tip clearance, which is the gap between the land surface of each blade and the partition wall 30 of the chamber 3, to the inner diameter of the chamber 3 is set to less than 0.02. This configuration can improve the cohesiveness of the material to be kneaded. It also improves physical properties. Note that a smaller tip clearance is more effective.

[0045] Furthermore, in this embodiment, the bite angle θ1 of each blade is set to 10° or more and 20° or less, so that the cohesiveness of the material to be kneaded can be improved. Also, the physical properties are improved. Note that the shallower the bite angle θ1, the higher the kneading effect.

[0046] Furthermore, in this embodiment, the central angle θ2 with respect to the land width of each blade is set to 14° or more, which improves the cohesiveness of the material to be kneaded. Furthermore, the physical properties are also improved. Note that the wider the land width, the higher the kneading effect.

[0047] Furthermore, in this embodiment, the twist angle θ3 of each blade relative to the axial direction is set to 35° or more and 55° or less, which improves the cohesiveness of the material to be kneaded. This also improves the physical properties. Furthermore, it is advantageous for distribution.

[0048] The present invention will be further described below with reference to examples, although the present invention is not limited to these examples.

[0049] <Governing equations for flow analysis> The governing equations for flow analysis are shown in Equation 1 and Equation 2, respectively. In this example, a three-dimensional continuity equation and a momentum conservation equation were used. Gravity was also considered as an external force term. For the simulation, commercially available fluid flow analysis software based on the finite difference method was used.

[0050]

[0051]

[0052] Here, u, ρ, t, p, η, and g represent the velocity vector, density, time, pressure, viscosity, and gravitational acceleration of each calculated calculation cell, respectively. In this example, to evaluate the behavior of the gas-liquid interface, the interface behavior was reproduced using flow analysis. As a model of the gas-liquid interface, the VOF method (Equation 3) was used, which considers only the liquid phase for the free surface.

[0053]

[0054] Here, F represents the liquid phase fraction of each calculation cell, where F = 0: void cell, 0 < F < 1: interface cell, and F = 1: fluid cell.

[0055] Using the above formulas, the average pressure, cooling performance, cumulative volume fraction, and mixing energy were calculated for the mixer 1 according to the present invention and a conventional mixer. The conventional mixer used for comparison was the internal mixer disclosed in Japanese Patent No. 4542605. However, the length of the mixing rotor in the axial direction, the material of the material to be mixed, and other conditions were the same as those of the mixer 1 according to the present invention.

[0056] <Average Pressure> Figure 6 is a graph showing the average pressure generated in the chamber of a kneader according to the prior art and the average pressure generated in chamber 3 of the kneader 1 according to the present invention. As shown in Figure 6, if the average pressure generated in the chamber of the kneader according to the prior art is taken as 100%, the average pressure generated in chamber 3 of the kneader 1 according to the present invention increases to about 140%. Note that the "effect threshold" shown in Figure 6 refers to a value that serves as a criterion for determining whether or not the effect of the present invention, that is, "being able to apply pressure to the material to be kneaded sufficiently and efficiently," is achieved.

[0057] <Cooling Performance> Fig. 7 is a graph showing the cooling performance of a kneader according to the conventional technology and the cooling performance of the kneader 1 according to the present invention. As shown in Fig. 7, if the cooling performance of the kneader according to the conventional technology is taken as 100%, the cooling performance of the kneader 1 according to the present invention is improved to about 113%.

[0058] <Cumulative Volume Fraction> Figure 8 is a graph showing the relationship between pressure and cumulative volume fraction. In Figure 8, the horizontal axis represents pressure, and the vertical axis represents cumulative volume fraction, which is the value obtained by integrating volumes below a certain pressure. The cumulative volume fraction can be rephrased as the proportion of the volume that is equal to or greater than a given pressure to the total volume. Note that the "effect threshold" shown in Figure 8 refers to a value that serves as a criterion for determining whether or not the effect of the present invention, "being able to apply pressure sufficiently and efficiently to the material to be kneaded," is achieved.

[0059] <Mixing energy> Fig. 9 is a graph showing the mixing energy imparted to the material to be mixed in a mixer according to the prior art and the mixing energy imparted to the material to be mixed in the mixer according to the present invention. As shown in Fig. 9, when the mixing energy of the mixer according to the prior art is set to 100%, the mixing energy of the mixer 1 according to the present invention is improved to about 111%.

[0060] The kneader 1 according to one embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment. The present invention also allows for the following modified embodiments.

[0061] (1) In the previous embodiment, an example was described in which the first kneading rotor 41 and the second kneading rotor 42 were so-called six-blade rotors, but the number of blades on each of the first kneading rotor 41 and the second kneading rotor 42 may be increased. For example, the first kneading rotor 41 and the second kneading rotor 42 may be configured as so-called eight-blade rotors. In this way, the meshing space increases, improving the cohesion of the material to be kneaded. Also, the kneading energy increases. Note that, from the viewpoint of ensuring a large volume for the kneading chamber 2 and from the viewpoint of preventing a deterioration in the intake of the material to be kneaded from the hopper 6 into the kneading chamber 2, it is preferable that the first kneading rotor 41 and the second kneading rotor 42 be six-blade rotors.

[0062] (2) The length of the center blade may be the same as the length of the short blade or the length of the long blade. That is, the length L2 of the first center blade 4112A and the second center blade 4113A in the axial direction may be the same as the length L3 of the first short blade 4115A and the second short blade 4116A in the axial direction, the length L1 of the first long blade 4111A in the axial direction, or the length L1 of the second long blade 4114A in the axial direction. From the viewpoint of preventing deterioration in the transferability of the material to be kneaded, it is preferable that the first kneading rotor and the second kneading rotor have center blades and short blades.

[0063] (3) The land width may be reduced. This improves the ability to take in the material to be kneaded. However, this reduces the ability of the material to be kneaded to be cohesive. Furthermore, the physical properties of the material may also be deteriorated.

[0064] (4) Each of the blades may be divided in the axial direction. This configuration improves the ability to take in the material to be kneaded. Note that, from the viewpoint of preventing deterioration in the cohesiveness of the material to be kneaded and a decrease in kneading energy, it is preferable that each blade is not divided in the axial direction.

[0065] (5) The tip clearance may be changed along the way. For example, the tip clearance of the first long blade 4111A of the first kneading rotor 41 may be changed partially along the first torsion direction. The same applies to the tip clearances of the other blades.

[0066] (6) In the previous embodiment, an example was described in which the rear slope 4114c of the second long blade of the first kneading rotor 41 is connected to the front slope 4111a of the first long blade of the first kneading rotor 41, but all or some of the blades other than these blades (the second long blade 4114A, the first long blade 4111A) may be connected to each other. This configuration increases the pressure acting on the material to be kneaded. The volume of the intermeshing space is increased, improving the cohesiveness of the material to be kneaded. In addition, the kneading energy is increased. Note that, from the viewpoint of ensuring a large volume for the kneading chamber 2, it is preferable that blades other than the second long blade 4114A and the first long blade 4111A are not connected to each other.

[0067] (7) One or more of the first long blade, first center blade, and second center blade of the first kneading rotor may extend in a first twisting direction from a position away from the first end face of the body portion as a base point. Also, one or more of the second long blade, first short blade, and second short blade of the first kneading rotor may extend in a second twisting direction from a position away from the second end face of the body portion as a base point. The same applies to the second kneading rotor. With this configuration, the volume of the kneading chamber 2 can be secured.

[0068] (8) In the previous embodiment, an example was described in which the blades extend in the same torsional direction and are arranged so that a space is formed between adjacent blades in the first rotation direction F. However, this space is not essential. In other words, the front slope and the rear slope of adjacent blades in the first rotation direction F may be connected.

[0069] (9) In the previous embodiment, an example was described in which the second long blade rear slope 4114c of the first mixing rotor 41 is connected to the first long blade front slope 4111a of the first mixing rotor 41, but the two do not have to be connected. The same applies to the second long blade rear slope 4214c and the first long blade front slope 4211a of the second mixing rotor 42.

[0070] The above-described embodiments mainly include inventions having the following configurations.

[0071] A hermetic mixer according to a first aspect of the present invention comprises a kneading chamber having a sealed space formed therein, and a first kneading rotor and a second kneading rotor that are opposed to each other in the width direction of the kneading chamber and disposed in the sealed space so as to be parallel to an axial direction perpendicular to the width direction, and that rotate in opposite directions to each other to knead a material to be mixed that has been introduced into the sealed space, and each of the first kneading rotor and the second kneading rotor comprises a first blade that extends in a radial direction and a first twisting direction that intersects the axial direction, and a fourth blade extending in a second torsional direction intersecting the first torsional direction and the first torsional direction, respectively, and a fifth blade and a sixth blade extending in the second torsional direction and having a length in the axial direction shorter than the length of the fourth blade in the axial direction, wherein the first kneading rotor has the first blade, the second blade, and the third blade arranged at one end side of the kneading chamber in the axial direction, and the fourth blade, the fifth blade, and the sixth blade arranged at the other end side of the kneading chamber in the axial direction, and the second kneading rotor has the fourth blade, the fifth blade, and the sixth blade arranged at one end side, and the first blade, the second blade, and the third blade arranged at the other end side.

[0072] According to this configuration, as the first kneading rotor and the second kneading rotor rotate, the first, second, and third blades of the first kneading rotor repeatedly approach and separate from the fourth, fifth, and sixth blades of the second kneading rotor, and the fourth, fifth, and sixth blades of the first kneading rotor repeatedly approach and separate from the first, second, and third blades of the second kneading rotor. Therefore, compared to a configuration in which the first kneading rotor and the second kneading rotor each have only three blades, meshing spaces surrounded by the blades of the first kneading rotor and the second kneading rotor, in which the material to be kneaded is subjected to pressure, can be formed more frequently. Therefore, pressure can be applied sufficiently and efficiently to the material to be kneaded. Furthermore, according to the above configuration, sufficient pressure can be applied to the material to be kneaded, thereby improving the cohesiveness of the material to be kneaded. Furthermore, according to the above configuration, sufficient pressure can be applied to the material to be kneaded, thereby increasing the kneading energy. Furthermore, with the above configuration, the material to be kneaded can be transferred more easily between the first kneading rotor and the second kneading rotor.

[0073] The second invention is the first invention, wherein the first blade and the second blade are arranged on one end side of the first kneading rotor and the second kneading rotor, in that order, forward in the direction of rotation of the rotor, and the fourth blade and the fifth blade and the sixth blade are arranged on the other end side of the rotor, in that order, forward in the direction of rotation of the rotor, and the first blade of the other kneading rotor, which is the other of the first kneading rotor and the second kneading rotor, is arranged so as to mesh with the fourth blade and the fifth blade of the one kneading rotor, which is one of the first kneading rotor and the second kneading rotor, and the first blade of the one kneading rotor is arranged so as to mesh with the fifth blade and the sixth blade of the other kneading rotor.

[0074] According to this configuration, a greater pressure can be applied to the material to be kneaded. As a result, the cohesiveness of the material to be kneaded can be further improved. In addition, the kneading energy is further increased. In addition, the transferability of the material to be kneaded between the first kneading rotor and the second kneading rotor is further improved.

[0075] A third invention is the first or second invention, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and a shaft portion extending from both end portions of the body portion, and the first blade, the second blade, and the third blade extend in the first torsional direction from a first end face located at an end of the body portion in the axial direction as a base point, and the fourth blade, the fifth blade, and the sixth blade extend in the second torsional direction from a second end face located on the opposite side of the body portion from the first end face in the axial direction as a base point.

[0076] This configuration allows the axial length of each blade to be longer than when the first, second, and third blades extend in the first twist direction from a position axially distant from the first end face as a base point, and when the fourth, fifth, and sixth blades extend in the second twist direction from a position axially distant from the second end face as a base point. This increases the total axial length of each blade, thereby increasing the area in which the material to be kneaded can be kneaded. As a result, the kneading energy is further increased.

[0077] A fourth invention is any one of the first to third inventions, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and a shaft portion extending from both end portions of the body portion, and one or more of the first blade, the second blade, and the third blade extend in the first torsional direction away from a first end face located at an end of the body portion in the axial direction, and one or more of the fourth blade, the fifth blade, and the sixth blade extend in the second torsional direction away from a second end face located on the opposite side of the body portion from the first end face in the axial direction.

[0078] According to this configuration, the volume of the kneading chamber can be secured.

[0079] A fifth invention is, in any one of the first to fourth inventions, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and a shaft portion extending from both end portions of the body portion, and each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade has a land surface located at the outer end in the radial direction, a front inclined surface arranged forward of the land surface, and a rear inclined surface arranged rearward of the land surface, and the rear inclined surface of the fourth blade may be connected to the front inclined surface of the first blade.

[0080] This configuration allows the length of both blades in the axial direction to be greater than when the rear slope of the fourth blade and the front slope of the first blade are not connected. This structure further improves the cohesiveness of the material to be mixed. Furthermore, the average pressure can be improved by about 20% compared to when the rear slope of the fourth blade and the front slope of the first blade are not connected.

[0081] A sixth invention is, in any one of the first to fifth inventions, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and shaft portions extending from both end portions of the body portion, wherein the length of the first blade in the axial direction is set to be half or more of the length of the body portion in the axial direction, and the sum of the length of the first blade in the axial direction and the length of the fourth blade in the axial direction is set to be one time or more the length of the body portion in the axial direction, the lengths of the second blade and the third blade in the axial direction are set to be one-fifth or more but less than one-half of the length of the body portion in the axial direction, and the lengths of the fifth blade and the sixth blade in the axial direction may be set to be one-fifth or less of the length of the body portion in the axial direction.

[0082] This configuration improves the transfer of the material to be kneaded between the first kneading rotor and the second kneading rotor, i.e., pressure and flow are generated effectively, increasing the flow rate of the material to be kneaded between the first kneading rotor and the second kneading rotor, and enabling the material to be mixed effectively.

[0083] A seventh invention is any one of the first to sixth inventions, wherein the bite angle of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade may be set to 10° or more and 20° or less.

[0084] According to this configuration, the cohesiveness of the material to be kneaded can be improved. Also, the physical properties are improved. Note that the shallower the bite angle, the higher the kneading effect.

[0085] An eighth invention is any one of the first to seventh inventions, wherein the central angle relative to the land width of each of the first wing, the second wing, the third wing, the fourth wing, the fifth wing, and the sixth wing may be set to 14° or more.

[0086] According to this configuration, the cohesiveness of the material to be kneaded can be improved. Also, the physical properties are improved. Note that the wider the land width, the higher the kneading effect.

[0087] A ninth invention is any one of the first to eighth inventions, wherein the twist angle of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade with respect to the axial direction may be set to be 35° or more and 55° or less.

[0088] According to this configuration, the cohesiveness of the material to be kneaded can be improved, the physical properties are improved, and it is also advantageous for distribution.

[0089] A tenth invention is any one of the first to ninth inventions, wherein the ratio of a tip clearance, which is a gap between each land surface of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade and the partition wall of the kneading chamber, to the inner diameter of the kneading chamber may be set to less than 0.02.

[0090] According to this configuration, the cohesion of the material to be kneaded can be improved. Also, the physical properties are improved. Note that a smaller tip clearance is more effective.

[0091] A kneading rotor for a hermetic mixer according to an eleventh aspect of the present invention is rotatably disposed in a hermetic space of a hermetic mixer having a hermetic space formed therein. The kneading rotor for a hermetic mixer has a first blade extending in a first twisting direction that intersects a radial direction and an axial direction perpendicular to the radial direction, second and third blades that extend in the first twisting direction and have lengths in the axial direction that are shorter than the lengths of the first blades in the axial direction, a fourth blade extending in a second twisting direction that intersects the radial direction, the axial direction, and the first twisting direction, and fifth and sixth blades that extend in the second twisting direction and have lengths in the axial direction that are shorter than the lengths of the fourth blades in the axial direction, wherein the first blade, the second blade, and the third blade are disposed at one end side in the axial direction, and the fourth blade, the fifth blade, and the sixth blade are disposed at the other end side in the axial direction.

Claims

1. A sealed mixer comprising: a mixing chamber having a sealed space formed therein; and a first mixing rotor and a second mixing rotor which are disposed in the sealed space so as to face each other in the width direction of the mixing chamber and be parallel to an axial direction perpendicular to the width direction, and which rotate in opposite directions to each other to mix a material to be mixed introduced into the sealed space; wherein each of the first mixing rotor and the second mixing rotor has a first blade extending in a first torsional direction which intersects the radial direction and the axial direction, respectively, a second blade and a third blade which extend in the first torsional direction and have a length in the axial direction that is shorter than the length of the first blade in the axial direction, a fourth blade which extends in a second torsional direction which intersects the radial direction, the axial direction, and the first torsional direction, respectively, and a fifth blade and a sixth blade which extend in the second torsional direction and have a length in the axial direction that is shorter than the length of the fourth blade in the axial direction, an internal mixer, wherein the first kneading rotor has the first blade, the second blade, and the third blade arranged on one end side of the kneading chamber in the axial direction, and the fourth blade, the fifth blade, and the sixth blade arranged on the other end side of the kneading chamber in the axial direction; and the second kneading rotor has the fourth blade, the fifth blade, and the sixth blade arranged on one end side, and the first blade, the second blade, and the third blade arranged on the other end side.

2. The closed type kneader according to claim 1, wherein the first blade and the second blade are arranged in this order at one end of the first kneading rotor and the second kneading rotor, and the fourth blade and the fifth blade and the sixth blade are arranged in this order at the other end of the rotor, and the first blade of the other kneading rotor, which is the other of the first kneading rotor and the second kneading rotor, is arranged so as to mesh with the fourth blade and the fifth blade of the other kneading rotor, which is one of the first kneading rotor and the second kneading rotor, and the first blade of the one kneading rotor is arranged so as to mesh with the fifth blade and the sixth blade of the other kneading rotor.

3. The closed-type mixer according to claim 1, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and shaft portions extending from both ends of the body portion, and the first blade, the second blade, and the third blade extend in the first torsional direction from a first end face located at an end of the body portion in the axial direction, and the fourth blade, the fifth blade, and the sixth blade extend in the second torsional direction from a second end face located on the opposite side of the body portion from the first end face in the axial direction.

4. The closed-type mixer according to claim 1, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and shaft portions extending from both ends of the body portion, and one or more of the first blade, the second blade, and the third blade extend in the first torsional direction away from a first end face located at an end of the body portion in the axial direction, and one or more of the fourth blade, the fifth blade, and the sixth blade extend in the second torsional direction away from a second end face located on the opposite side of the body portion from the first end face in the axial direction.

5. The closed-type mixer according to claim 1, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and a shaft portion extending from both ends of the body portion, and each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade has a land surface located at the outer end in the radial direction, a front inclined surface arranged forward of the land surface, and a rear inclined surface arranged rearward of the land surface, and the rear inclined surface of the fourth blade is connected to the front inclined surface of the first blade.

6. The closed-type mixer according to claim 1, wherein the first kneading rotor and the second kneading rotor each have a cylindrical body portion supporting the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade, and shaft portions extending from both ends of the body portion; the length of the first blade in the axial direction is set to be at least half the length of the body portion in the axial direction, and the sum of the length of the first blade in the axial direction and the length of the fourth blade in the axial direction is set to be at least one time the length of the body portion in the axial direction; the lengths of the second blade and the third blade in the axial direction are set to be at least one-fifth but less than one-half the length of the body portion in the axial direction; and the lengths of the fifth blade and the sixth blade in the axial direction are set to be no more than one-fifth of the length of the body portion in the axial direction.

7. The internal mixer according to claim 1, wherein the bite angle of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade is set to be 10° or more and 20° or less.

8. The internal mixer according to claim 1, wherein the central angle relative to the land width of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade is set to 14° or more.

9. The internal mixer according to claim 1, wherein the twist angle of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade with respect to the axial direction is set to be 35° or more and 55° or less.

10. The closed-type kneader according to claim 1, wherein the ratio of the tip clearance, which is the gap between the land surface of each of the first blade, the second blade, the third blade, the fourth blade, the fifth blade, and the sixth blade and the partition wall of the kneading chamber, to the inner diameter of the kneading chamber is set to less than 0.

02.

11. A kneading rotor for a hermetic mixer, which is rotatably arranged in the hermetic space of a hermetic mixer having a hermetic space formed therein, the kneading rotor having: a first blade extending in a first twisting direction that intersects a radial direction and an axial direction perpendicular to the radial direction; second and third blades extending in the first twisting direction and having lengths in the axial direction that are shorter than the lengths of the first blades in the axial direction; a fourth blade extending in a second twisting direction that intersects the radial direction, the axial direction, and the first twisting direction, respectively; and fifth and sixth blades extending in the second twisting direction and having lengths in the axial direction that are shorter than the lengths of the fourth blades in the axial direction, wherein the first blade, the second blade, and the third blade are arranged at one end side in the axial direction, and the fourth blade, the fifth blade, and the sixth blade are arranged at the other end side in the axial direction.

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