Internal mixer

Abstract

An internal mixer includes a mixing chamber having a mixing compartment, a material inlet portion situated above the mixing chamber, a weight, a drive device that raises and lowers the weight between a lower position where the weight can press a material to be mixed into the mixing compartment from above and a retraction position where the weight is retracted upwards from the lower position, a mixing rotor that mixes the material to be mixed in the mixing compartment, and an exhaust device having an inner end portion facing the mixing compartment and provided in the mixing chamber and configured to be able to vent the gas generated during the mixing of the material to be mixed from the inner end to the outside of the mixing chamber.

Description

Title of the invention: Internal mixer FIELD OF INVENTION

[0001] The present invention relates to an internal mixer. PREVIOUS ART

[0002] As disclosed in publicly available Japanese patent application No. Hei 10-217240, publicly available Japanese patent application No. 2016-43520, publicly available Japanese patent application No. Hei 7-232320, publicly available Japanese patent application No. 2013-107025 and publicly available Japanese patent application No. 2007-118387, there is a classically known internal mixer comprising a mixing chamber having a mixing compartment with an open upper part, and a weight arranged so as to be able to move up and down in the mixing compartment, the internal mixer kneading a material to be kneaded while pressing the material to be kneaded from above with the help of the weight in the mixing compartment.The mixers described in Japanese Public Patent Application No. Hei 10217240, Japanese Public Patent Application No. 2016-43520, and Japanese Public Patent Application No. Hei 7-232320 are used in a mixing process for introducing oil and mixing raw rubber. A mixer described in Japanese Public Patent Application No. 2013-107025 is used in a mixing process in which a mixing material, such as rubber or plastic, and a powdered mixing agent are introduced together into a mixing chamber to mix a material to be mixed. The mixer described in Japanese Public Patent Application No. 2013-107025 has a vent connected to a mixing chamber, and the vent has an inflatable bag with a filter body.As a result, the dust-containing gas accompanying the powdered mixing agent can be prevented from dispersing outside. The mixer described in publicly available Japanese patent application no. 2007-118387 is configured to reduce the particle concentration in the mixing compartment by introducing an inert gas into the mixing compartment.

[0003] In a mixer in which a material to be mixed is mixed in a state where a weight descends to close an upper opening of a mixing compartment, for example, when a material to be mixed containing a large amount of moisture is mixed, the moisture vaporizes as the temperature increases during mixing, and the internal pressure in the mixing compartment may increase. Furthermore, gas may escape. The gap between the edge of the mixing chamber's upper opening and the weight is a factor, but even then, when a large amount of moisture is vaporized, the pressure inside the mixing chamber can increase. Furthermore, the material to be mixed and the additive can become trapped in this gap, preventing degassing. SUMMARY OF THE INVENTION

[0004] The object of the present invention is to provide an internal mixer suitable for mixing a material to be mixed in which a large quantity of gas, such as steam, is generated.

[0005] An internal mixer according to one aspect of the present invention comprises: a mixing chamber having a mixing compartment with a top opening; a material inlet portion located above the mixing chamber, having an interior space communicating with the mixing compartment, and configured to be able to introduce a material to be mixed into the interior space; a weight provided in the interior space; a drive device configured to move the weight up and down between a lower position and a retraction position, the lower position being a position in which the weight enters the mixing compartment and is able to press the material to be mixed into the mixing compartment from above, and the retraction position being a position in which the weight retracts from the lower position to open the mixing compartment;a pair of mixing rotors configured to mix the material to be mixed in the mixing compartment; and an exhaust device having an inner end portion facing the mixing compartment and provided within the mixing chamber, the exhaust device being configured to vent the gas generated during the mixing of the material to be mixed from the inner end portion to the outside of the mixing chamber. BRIEF DESCRIPTION OF THE DRAWINGS;

[0006] [Fig. 1] The [Fig. 1] is a cross-sectional view of an internal mixer according to the present embodiment, seen from the side. [Fig.2] Fig.2 is a cross-sectional view of the internal mixer according to the present embodiment, seen from the top of a mixing chamber. [Fig.3] The [Fig.3] is a diagram illustrating an escape device provided in the internal mixer and illustrating a state in which a rod is in a closed position. [Fig. 4] Fig. 4 is a diagram illustrating the escapement device provided in the internal mixer and showing a state in which the rod is in an open position. [Fig. 5] Fig. 5 is a diagram illustrating an escapement device provided in an internal mixer according to a first modification. [Fig.6] The [Fig.6] is a diagram illustrating an escape device provided in an internal mixer according to a second modification. DETAILED DESCRIPTION

[0007] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0008] As illustrated in Figures 1 and 2, an internal mixer 50 according to the present embodiment is an apparatus for mixing a material to be mixed, such as rubber or resin. The mixer 50 comprises a mixing chamber 25 having a mixing compartment 21 with a top opening 21a, a material inlet portion 27 located above the mixing chamber 25, and a weight 28 disposed in the material inlet portion 27.

[0009] The mixing compartment 21 is a compartment for mixing a material to be mixed. A pair of mixing rotors 20 is arranged in the mixing compartment 21. The rotors of the pair of mixing rotors 20 are arranged in a rotating manner parallel to each other in the mixing compartment 21. The rotor shafts 22A and 22B extend from both sides of each mixing rotor 20 in the axial direction. The rotor shafts 22A and 22B penetrate end plates 23A and 23B, described later, of the mixing chamber 25, and are driven and rotated by a motor (not shown) located outside the mixing chamber 25. The pair of mixing rotors 20 is driven to mix the material to be mixed in the mixing compartment 21.

[0010] The material inlet part 27 has an internal space 27a communicating with the mixing compartment 21. The material inlet part 27 is provided with a hopper 30 through which the material of the material to be mixed can be introduced into the internal space 27a of the material inlet part 27.

[0011] The weight 28 is designed to move up and down within the internal space 27a of the material inlet portion 27. The weight 28 is connected to a drive device 32 for raising and lowering the weight 28 by means of a connecting rod 29. The drive device 32 moves the weight 28 up and down between the lower position and the retracted position. The drive device 32 may include, for example, a cylinder (not shown) and a piston (not shown) slidably arranged within the cylinder, and may be configured to move the weight 28 in the vertical direction via the connecting rod 29 by a reciprocating motion of the piston. The drive device 32 applies a downward force to the weight 28 so that the weight 28 can compress the material to be mixed.

[0012] When the weight 28 is in the lower position, the weight 28 enters the upper opening 21a of the mixing compartment 21. The weight 28 can thus press the The material to be mixed enters the mixing compartment 21 from the top. When the weight 28 is in its lower position, the upper opening 21a of the mixing compartment 21 is substantially closed by the weight 28. At this point, a gap is created between the inner peripheral portion defining the upper opening 21a in the mixing chamber 25 and the peripheral edge of the weight 28 in its lower position. Consequently, if the internal pressure of the mixing compartment 21 increases, air (which in some cases may also include the introduced powdered material) in the mixing compartment 21 can escape into the inner space 27a of the material inlet portion 27 through this gap.

[0013] The retraction position is a position in which the weight 28 is raised relative to the lower position, and when the weight 28 is in the retraction position, the upper opening 21a of the mixing compartment 21 is open towards the inner space 27a of the material inlet part 27. The weight 28 can be raised to a position located above the connecting part of the hopper 30 in the material inlet part 27.

[0014] The mixing chamber 25 comprises a cylindrical chamber body 25a and a pair of end plates 23A and 23B that close the openings at both ends of the chamber body 25a. The chamber body 25a is cylindrical in shape surrounding the pair of mixing rotors 20, and an upper opening 21a, which allows the mixing compartment 21 and the internal space 27a of the material inlet portion 27 to communicate with each other, is formed in an upper portion of the chamber body 25a. An exhaust port 26 for discharging the material to be mixed is provided in a lower portion of the chamber body 25a. The exhaust port 26 is closed when the material to be mixed is being stirred and is opened by a discharge instruction.

[0015] The chamber body 25a is formed in a cylindrical shape in which both ends in the extension direction of the rotor shafts 22A and 22B of the mixing rotor 20 are open. The end plates 23A and 23B are coupled to the end surfaces of the chamber body 25a from the outside in the extension direction of the rotor shafts 22A and 22B so as to close the openings at both ends of the chamber body 25a. The end plates 23A and 23B are provided with through holes 23a and 23b through which the rotor shafts 22A and 22B are inserted, and the end plates 23A and 23B are provided with bearings 24A and 24B that rotatably support the rotor shafts 22A and 22B.

[0016] The length of the chamber body 25a is greater than the length of the mixing rotor 20 in the direction of extension of the rotor shafts 22A and 22B (or in the left-to-right direction in Figures 1 and 2). Thus, an end surface 20a of the mixing rotor 20 in the direction of extension of the rotor shafts 22A and 22B and The inner surfaces 23c and 23d of the end plates 23A and 23B are separated from each other. In other words, a gap is also formed between the end surface 20a of the mixing rotor 20 and the inner surfaces 23c and 23d of the end plates 23A and 23B.

[0017] The space in the mixing compartment 21 comprises a mixing zone MS at a position corresponding to the mixing rotor 20 and an adjacent zone AS at a position offset from the mixing zone MS in the direction of extension of the rotor shafts 22A and 22B. The adjacent zone AS is adjacent to the mixing zone MS.

[0018] The mixing zone MS is a space located between the end surfaces 20a and 20a of the mixing rotor 20 in the direction in which the rotor shafts 22A and 22B extend when viewed in the direction orthogonal to the rotor shafts 22A and 22B (as viewed in the direction perpendicular to the plane of the paper in [Fig. 1]). During mixing, the material to be mixed is primarily mixed in the mixing zone MS of the mixing compartment 21. The mixing zone MS comprises a space above the pair of mixing rotors 20, a space below them, a space on their right side, and a space on their left side.

[0019] The adjacent zone AS is a space located outside the end surface 20a of the mixing rotor 20 in the extension direction of the rotor shafts 22A and 22B. The adjacent zone AS comprises a facing space confronting the end surfaces 20a of the pair of mixing rotors 20 and an outer annular peripheral space located on the outer circumference of the facing space. The facing space is a space between the end surface 20a of the mixing rotor 20 and the inner surfaces 23c and 23d of the end plates 23A and 23B facing the end surface 20a.

[0020] The mixing chamber 25 is provided with an exhaust device 12 configured to vent the gas generated during the mixing of the material to be mixed, from the mixing compartment 21. The exhaust device 12 has an inner end 12a facing the mixing compartment 21, and is configured to vent the gas present in the mixing compartment 21 to the outside of the mixing compartment 21 from the inner end 12a.

[0021] In other words, during the mixing stage of the material to be mixed, a gas (including evaporated moisture or similar) may be generated from the material to be mixed. This gas escapes from the mixing compartment 21 into the internal space 27a of the material inlet portion 27 through the gap around the weight 28. Therefore, if the amount of gas generated during mixing is not significant, the internal pressure of the mixing compartment 21 does not increase considerably. However, when the material to be mixed contains a large amount of evaporated moisture When the mixture is mixed, a significant amount of gas is generated, and the internal pressure in the mixing compartment 21 can increase. Therefore, the exhaust device 12 is designed to vent the gas from the mixing compartment 21 other than through the gap around the weight 28 in order to limit the pressure increase in the mixing compartment 21.

[0022] In this embodiment, the exhaust device 12 is provided in each of the pair of end plates 23A and 23B. Consequently, the inner ends 12a of the exhaust devices 12 are positioned on the inner surfaces 23c and 23d of the end plates 23A and 23B and face the adjacent area AS. During mixing, the material to be mixed flows into the mixing area MS when the mixing rotor 20 is driven. Therefore, even if the exhaust device 12 for venting gas from the mixing compartment 21 is arranged so that its inner end 12a is located in the adjacent area AS, the possibility of the material to be mixed coming into contact with the inner end 12a of the exhaust device 12 can be reduced.

[0023] In this embodiment, the inner end 12a of the exhaust device 12 is located in a space above the pair of mixing rotors 20 in the outer peripheral space included in the adjacent zone AS. In other words, as illustrated in [Fig. 1], the inner end 12a of the exhaust device 12 is located above the upper end of the mixing rotor 20 in the outer peripheral space (or adjacent zone AS). This further reduces the possibility of the material to be mixed coming into contact with the inner end 12a of the exhaust device 12. The inner end 12a of the exhaust device 12 is not necessarily located above the mixing rotor 20, but may be located above the rotor shafts 22A and 22B in the adjacent zone AS, or may be located below the rotor shafts 22A and 22B in the adjacent zone AS.

[0024] In the present embodiment, as illustrated in [Fig. 2], the inner end 12a of the escapement device 12 is located at an intermediate point between the rotor shaft pair 22A and 22A and an intermediate point between the rotor shaft pair 22B and 22B when viewed from above. However, the escapement device 12 does not need to be arranged in this position and can be arranged in a different position.

[0025] As illustrated in [Fig.3], the exhaust device 12 comprises a cylindrical rod guide 3 inserted into a through hole 23e formed in each of the end plates 23A and 23B, a venting orifice 10 provided in the rod guide 3, and an exhaust passage 13 (see figures 1 and 2) provided in each of the end plates 23A and 23B so as to communicate with the venting orifice 10. The exhaust passage 13 allows the degassing orifice 10 and the outer surfaces of the end plates 23A and 23B (the outer surface of the mixing chamber 25) to communicate with each other.

[0026] The through hole 23e into which the guide rod 3 is inserted passes through the end plates 23A and 23B between the inner surfaces 23c and 23d of the end plates 23A and 23B and the outer surfaces of the end plates 23A and 23B. The guide rod 3 is arranged in the through hole 23e so as to open onto the inner surfaces 23c and 23d of the end plates 23A and 23B. Therefore, the gas present in the mixing compartment 21 can be vented to the outside of the mixing chamber 25 through the space in the guide rod 3, the venting orifice 10 and the exhaust passage 13. In this case, the inner end part (i.e. an inner opening 9) of the guide rod 3 functions as the inner end 12a of the exhaust device 12 which opens towards the mixing compartment 21.

[0027] The exhaust passage 13 and the degassing orifice 10 can be used to blow air from outside the mixing chamber 25. By blowing air from the outside, it is possible to remove an obstruction in the guide rod 3.

[0028] The exhaust device 12 further includes a rod 7 disposed in the rod guide 3 and a cylinder 4 for moving the rod 7. The rod 7 is disposed so as to extend outwards from the inside of the cylinder 4. The cylinder 4 is fixed to the outer end (base end) of the rod guide 3 by means of a support 5.

[0029] The cylinder 4 is configured to move the rod 7 forward and backward so that the vent orifice 10 is opened and closed by the rod 7. In other words, the cylinder 4 slides the rod 7 between an open position (illustrated in [Fig. 3]) in which the distal end of the rod 7 (end on the mixing compartment 21 side) is located on the side of the mixing compartment 21 relative to the vent orifice 10, and an open position (position illustrated in [Fig. 4]) where the distal end of the rod 7 is located on the opposite side of the mixing compartment 21 relative to the vent orifice 10. The cylinder 4 operates by receiving hydraulic or similar pressure, but is not limited to this.

[0030] When the rod 7 is in the closed position, the degassing orifice 10 is closed by the rod 7 as illustrated in [Fig. 3]. Consequently, degassing in the mixing compartment 21 can be stopped. In this case, the distal end of the rod 7 can close the inner end portion (i.e., the inner opening 9) of the rod guide 3. Thus, the material to be mixed in the mixing compartment 21 can be prevented from entering the rod guide 3. At this stage, the distal end surface of the rod 7 can be aligned with the inner surfaces 23c and 23d of the plates end plates 23A and 23B (or the inner surfaces of the mixing chamber 25). In other words, the distal end surface of the rod 7 and the inner surfaces 23c and 23d of the end plates 23A and 23B (or the inner surfaces of the mixing chamber 25) can be located on the same surface. When the distal end of the rod 7 is movable to a position where the distal end does not protrude from the inner surfaces 23c and 23d of the end plates 23A and 23B (or the inner surfaces of the mixing chamber 25), the distal end of the rod 7 can be prevented from interfering with the mixing.

[0031] When the rod 7 is in the open position, the degassing orifice 10 is opened by the rod 7, as illustrated in [Fig. 4]. In this case, degassing is carried out in the mixing compartment 21.

[0032] A vent pipe (not shown) is connected to the exhaust passage 13. The vent pipe is connected to a scraper (not shown) or similar device, and contaminants are removed. Consequently, the gas evacuated from the mixing compartment 21 is released into the atmosphere in a purified and cooled state. The vent pipe may be equipped with an opening / closing mechanism, and in this case, the activation / deactivation of venting can be controlled by an opening / closing operation of the opening / closing mechanism.

[0033] Cylinder 4 is actuated by a command from a controller (not shown) to drive rod 7. As a result, the vent 10 can be opened when the gas in the mixing compartment 21 is evacuated or when air is blown in from the outside. When no command is received from the controller, cylinder 4 can position rod 7 in a closed position where the vent 10 is closed by rod 7. Furthermore, the controller can drive rod 7 so that rod 7 repeats its forward and backward movement between the open and closed positions at predetermined time intervals. Consequently, the mixing material entering the rod guide 3 can be pushed toward the mixing compartment 21.The controller can command the actuation of the two rods 7 so that the rod 7 of one exhaust device 12 opens the degassing orifice 10 and the rod 7 of the other exhaust device 12 closes the degassing orifice 10. Then, the controller can command the actuation of the two rods 7 so that this action repeats alternately. As a result, it is possible to continuously evacuate air from the mixing compartment 21 while preventing the material to be mixed from becoming obstructed in the rod guide 3.

[0034] In the case where a powdered material is mixed with the material to be mixed, it may be necessary to vent the gas while preventing the powdered material from being evacuated. In this case, the actuation delay of cylinder 4 may be controlled so as to move the rod 7 to the open position after mixing has been carried out for a predetermined time.

[0035] In this case, for example, a timer that starts after the mixing begins is provided, and the controller can position the rod 7 in the closed position until the measured time reaches a predefined time, then position the rod 7 in the open position where the degassing orifice 10 is open when the measured time reaches the predefined time. Alternatively, a sensor for detecting the temperature of the mixing chamber 25 can be provided, and the controller can position the rod 7 in the closed position until the temperature detected by this sensor reaches a predefined temperature, then position the rod 7 in the open position where the degassing orifice 10 is open when the detected temperature reaches the predefined temperature.Alternatively, a linear sensor that monitors the position of the weight 28 can be provided, and the controller can issue a command to position the rod 7 in the closed position until the position of the weight 28 is lowered to the reference position, and open the vent 10 when it detects that the position of the weight 28 has been lowered to the reference position. Furthermore, when the temperature detected by the temperature sensor attached to the exhaust port 26 reaches a predefined temperature, a command can be issued to open the vent 10. In addition, a sensor that detects the power (or the current or voltage value) of the motor driving the rotor shafts 22A and 22B can be provided, and when it is detected that the value detected by the sensor begins to decrease below a peak value, a command to open the vent 10 can be issued.

[0036] The through hole 23e in which the guide rod 3 is disposed is formed so as to extend in an oblique direction. In other words, the through hole 23e extends obliquely upwards from an open end portion towards the inner surfaces 23c and 23d of the end plates 23A and 23B or from the inner opening 9. This facilitates the attachment of the guide rod 3 and the attachment of the cylinder 4 to the guide rod 3. Furthermore, it is thus possible to prevent the material to be mixed from entering the guide rod 3. In addition, lubricating oil injected from an injection port 6 described later can be easily distributed over the inner surface of the guide rod 3.

[0037] Since the rod 7 and the rod guide 3 are arranged obliquely, the distal end of the rod 7 is cut obliquely. As a result, the distal end surface of the rod 7 fits easily into the inner surfaces 23c and 23d of the end plates 23A and 23B.

[0038] A boss 8 is provided in an intermediate portion of the rod 7. The boss 8 is a wider portion than the rod 7 and is in contact with the inner surface of the guide- rod 3. The rod guide 3 is provided with the injection port 6 in a position closer to the cylinder 4 than the degassing port 10. The injection port 6 can be used to inject liquid into the rod guide 3. Examples of liquid include a lubricating oil for lubricating the rod, a processing oil for mixing with a material to be blended in order to modify the characteristics of the material to be blended, and a liquid for pushing the material to be blended or by-products obstructing the rod guide 3 into the mixing compartment 21.

[0039] The cylinder 4 moves the rod 7 so that the boss 8 can selectively assume a state in which it is located closer to the mixing compartment 21 than to the injection port 6 (state illustrated in [Fig. 3]) and a state in which it is located closer to the cylinder 4 than to the injection port 6 (state illustrated in [Fig. 4]). In the state illustrated in [Fig. 3], the boss 8 is positioned between the injection port 6 and the mixing compartment 21, and the space between the injection port 6 and the mixing compartment 21 is closed. This state can be called the "closed state." In the closed state, even if the material to be mixed in the mixing compartment 21 enters the rod guide 3, it is possible to prevent the material to be mixed from reaching the injection port 6.

[0040] In the state illustrated in [Fig. 4], since the boss 8 is further from the mixing compartment 21 than the injection port 6, the injection port 6 and the mixing compartment 21 communicate with each other. This state can be called the "communication state." In the communication state, the liquid injected from the injection port 6 can flow into the mixing compartment 21.

[0041] As illustrated in [Fig. 4], the position of the boss 8 is adjusted so that it is in the communication state when the rod 7 is in the open position (the position in which the degassing orifice 10 is open), but the present invention is not limited to this. When the rod 7 is in the open position, the position of the boss 8 can be adjusted so that it is in the closed state. In other words, even when the degassing orifice 10 is open, the position of the boss 8 can be adjusted so that the gap between the injection orifice 6 and the mixing compartment 21 is closed by the boss 8. In this case, even when degassing is performed, the material to be mixed can be prevented from reaching the injection orifice 6.

[0042] In the present embodiment, the exhaust device 12 is provided on each of the end plates 23A and 23B on both sides. Therefore, while degassing from the degassing port 10 can be carried out in only one exhaust device 12, a liquid can be injected from the injection port 6 into the other exhaust device 12.

[0043] In the internal mixer 50 of the present embodiment having the configuration described above, the material to be mixed is introduced from the inlet part of Material 27 is placed in the mixing chamber 25 with the weight 28 in the retracted position. Once the material to be mixed is introduced, the weight 28 moves to the lower position and enters the upper opening 21a of the mixing chamber 25, so that the upper opening 21a of the mixing compartment 21 is substantially closed. When the pair of mixing rotors 20 is driven in this state, the material to be mixed is blended in the mixing compartment 21.

[0044] During mixing, a large quantity of gas can be generated from the material being mixed. However, the exhaust device 12 is provided in the mixing chamber 25 such that its inner end 12a faces the inner surface of the mixing compartment 21. Consequently, the gas present in the mixing compartment 21 can be vented out of the mixing chamber 25 through the exhaust device 12. Thus, even when mixing a material in which a large quantity of gas is generated, it is possible to suppress an increase in the internal pressure of the mixing compartment 21, so that such a material can still be mixed.

[0045] When the weight 28 is in its lower position, a gap is formed between the inner peripheral edge of the upper opening 21a in the mixing compartment 21 and the outer peripheral surface of the weight 28. Consequently, the gas generated from the material to be mixed can be vented from the mixing compartment 21 to the inner space 27a of the material inlet portion 27 through this gap. At this stage, if the amount of gas generated by the material to be mixed is small, simply venting the gas through the gap may be sufficient. However, if a large amount of gas is generated from the material to be mixed, simply venting the gas through the gap is not sufficient to prevent a pressure increase in the mixing compartment 21. Thus, degassing by the exhaust device 12 can limit an increase in the internal pressure of the mixing compartment 21.

[0046] In this embodiment, the exhaust device 12 is provided on each of the end plates 23A and 23B on both sides, and the inner end 12a of the exhaust device 12 is located in the adjacent zone AS of the mixing compartment 21. In the mixing compartment 21, the material to be mixed flows into the mixing zone MS when the mixing rotor 20 rotates, but the material to be mixed is unlikely to enter the adjacent zone AS. Therefore, the possibility of the flowing material to be mixed coming into contact with the inner end 12a of the exhaust device 12 is reduced. Consequently, it is possible to reduce the penetration of some of the material to be mixed into the exhaust device 12. Therefore, even if the Exhaust device 12 is provided in the mixing chamber 25, exhaust device 12 is less likely to be obstructed by the material to be mixed.

[0047] Furthermore, degassing can be carried out uniformly on both sides in the axial direction of the rotor shafts 22A and 22B. Even if one exhaust device 12 is obstructed, degassing can be carried out from the other exhaust device 12.

[0048] In this embodiment, the inner end 12a of the exhaust device 12 is located in a space above the mixing rotor 20 in the adjacent area AS. Thus, the inner end 12a of the exhaust device 12 is less likely to come into contact with the material to be mixed, thereby further reducing the possibility of the material to be mixed remaining trapped in the exhaust device 12 when the vaporized component is evacuated during degassing by the exhaust device 12. Consequently, this configuration is more suitable for degassing.

[0049] In this embodiment, since the exhaust device 12 comprises the rod 7 capable of opening and closing the vent orifice 10 and the cylinder 4 which moves the rod 7, the vent orifice 10 can be closed by the rod 7 when venting is not required. Thus, the rod 7 can prevent obstruction of the space in the rod guide 3. During venting, the vent orifice 10 is opened by the rod 7, allowing venting from the peripheral surface of the rod guide 3.

[0050] When the rod 7 is in the closed position, the rod 7 is positioned so that its distal end surface is aligned with the inner surfaces 23c and 23d of the end plates 23A and 23B. Thus, even when the rod 7 is driven by the cylinder 4 to slide into the closed position, the rod 7 does not protrude into the mixing zone MS. Consequently, the rod 7 does not interfere with the pair of mixing rotors 20.

[0051] Furthermore, in the present embodiment, the boss 8 is provided in the intermediate part of the rod 7, and the space in the rod guide 3 can selectively assume the closed state and the communication state under the effect of the movement of the boss 8. In the closed state, where the boss 8 is located closer to the mixing compartment 21 than to the injection port 6, the injection port 6 can be prevented from being blocked by the material to be mixed in the mixing compartment 21. In addition, a liquid, such as oil, injected through the injection port 6 can spread into the rod guide 3 by the movement of the boss 8 accompanying the movement of the rod 7. On the other hand, in the communication state, where the boss 8 is located on the side of the cylinder 4 relative to the injection port 6, it is possible to remove an object obstructing the space in the guide rod 3 in the mixing compartment 21, by injecting the liquid. Furthermore, if it is necessary to introduce a liquid during mixing, the liquid can be introduced into the mixing compartment 21 via the exhaust device 12. In addition, since it is not necessary to provide an injection mechanism on the end plates 23A and 23B separately from the exhaust device 12, it is possible to avoid increasing the number of processing steps for the end plates 23A and 23B.

[0052] It should be understood that the embodiment described herein is illustrative in all respects and is in no way restrictive. The present invention is not limited to the above embodiment, and various modifications, improvements, and other enhancements may be made without departing from the essence of the present invention.

[0053] In the above embodiment, the exhaust device 12 comprises the guide rod 3 provided with the vent orifice 10, the rod 7 arranged in the guide rod 3, and the cylinder 4 which moves the rod 7, and is configured to open and close the vent orifice 10 by the forward and backward movement of the rod 7, but the present invention is not limited to this. For example, as illustrated in [Fig. 5], the exhaust device 12 may include a through hole 23e formed in each of the end plates 23A and 23B, an external pipe 34 connected to each of the end plates 23A and 23B so as to be connected to the through hole 23e, and an on / off valve 35 provided in the external pipe 34. In this configuration, the degassing function provided by the through hole 23e is activated and deactivated by the opening and closing operation of the on / off valve 35.In this case, if the inner end 12a of the exhaust device 12 is located in the adjacent area AS in the mixing compartment 21, it is possible to prevent the material to be mixed from entering the through hole 23e.

[0054] As illustrated in [Fig. 6], the exhaust device 12 may include a rod 7 disposed in a through hole 23e formed in each of the end plates 23A and 23B (mixing chamber 25), and a cylinder 4 which moves the rod 7 forward and backward, and a cover element 37 which opens and closes an inner end portion of the through hole 23e may be provided at a distal end of the rod 7. In this configuration, even when a gap is formed between the outer peripheral surface of the rod 7 and the inner peripheral surface of the through hole 23e, the through hole 23e is closed by the placement of the cover element 37 on the inner end portion of the through hole 23e.An exhaust passage 13 branches off from the through hole 23e, and a gas present in the mixing compartment 21 is vented outside the mixing chamber 25 through the through hole 23e and the exhaust passage 13 when the cover element 37 separates from the inner surfaces 23c and 23d of the end plates 23A and 23B (mixing chamber 25).

[0055] In this case, the inner end portion of the through hole 23e can be formed to extend, and the cover element 37 can be configured to make surface contact with the inner end portion of the through hole 23e. The cover element 37 can be configured so as not to protrude from the inner surfaces 23c and 23d of the end plates 23A and 23B (mixing chamber 25) when it is placed on the inner end portion of the through hole 23e.

[0056] Furthermore, in the configuration in which the cover element 37 is provided, a positioning mechanism 39 for the rod 7 can be added. The positioning mechanism 39 is disposed between the outer peripheral surface of the rod 7 and the inner peripheral surface of the through hole 23e in order to prevent the rod 7 from moving in the radial direction. A clearance between the rod 7 and the rod guide 3 formed by the positioning mechanism 39 acts as an escape path. Moreover, if a rotation prevention mechanism (not shown) for the rod 7 is added to the cylinder 4 to prevent the rotation of the rod 7, it is not necessary to form the inner end portions of the cover element 37 and the through hole 23e so that they have circular cross-sections.For example, even if the inner end portions of the cover element 37 and the through hole 23e are each formed in an elliptical shape (or a shape other than a circular shape), the cover element 37 can be positioned along the inner end portion of the through hole 23e. Therefore, even if the inner end portions of the cover element 37 and the through hole 23e have a shape other than a circular cross-section, it is possible to prevent the cover element 37 from protruding from the inner surfaces 23c and 23d of the end plates 23A and 23B (mixing chamber 25) into the mixing compartment 21 due to the rotation of the rod 7 around the axis.Therefore, it is possible to prevent the mixing material from accumulating around the cover element 37, and to prevent the through hole 23e from being blocked by the mixing material accumulating around the cover element 37, and to prevent a drainage failure from occurring.

[0057] In the above embodiment, the injection orifice 6 is provided in the guide rod 3, but the present embodiment is not limited to this. In other words, the injection orifice 6 can be provided so as to penetrate the end plates 23A and 23B (mixing chamber 25) separately from the through hole 23e in which the guide rod 3 is disposed.

[0058] In the above embodiment, the escapement device 12 is provided in each of the pair of end plates 23A and 23B, but the present embodiment of The implementation is not limited to this. The exhaust device 12 can, for example, be provided only on one of the end plates 23A and 23B.

[0059] In the above embodiment, the exhaust device 12 is provided in each of the end plates 23A and 23B, but the present embodiment is not limited to this. In other words, the exhaust device 12 can be provided in the chamber body 25a of the mixing chamber 25. Even in this case, the inner end 12a of the exhaust device 12 faces the mixing compartment 21. In this case, the inner end 12a of the exhaust device 12 is preferably located in the adjacent area AS and faces the adjacent area AS. That is to say, when the exhaust device 12 is provided in the chamber body 25a, the exhaust device 12 is preferably provided in a portion located on the outer side in the axial direction relative to the pair of mixing rotors 20 in the chamber body 25a.

[0060] The embodiments will be described here succinctly.

[0061] The internal mixer according to the embodiment may include: a mixing chamber having a mixing compartment with a top opening; a material inlet portion located above the mixing chamber, having an internal space communicating with the mixing compartment, and configured to be able to introduce a material to be mixed into the internal space; a weight provided in the internal space; a drive device configured to move the weight up and down between a lower position and a retraction position, the lower position being a position in which the weight enters the mixing compartment and is able to press the material to be mixed into the mixing compartment from above, and the retraction position being a position in which the weight retracts from the lower position to open the mixing compartment;a pair of mixing rotors configured to mix the material to be mixed in the mixing compartment; and an exhaust device having an inner end portion facing the mixing compartment and provided in the mixing chamber, the exhaust device being configured to vent the gas generated during the mixing of the material to be mixed from the inner end portion to the outside of the mixing chamber.

[0062] In the internal mixer, the material to be mixed is introduced from the material inlet into the mixing chamber with the weight in the retracted position. Once the material is introduced, the weight moves to the lower position and enters the upper opening of the mixing compartment. When the pair of mixing rotors is driven in this state, the material to be mixed is blended within the mixing compartment. During blending, a large quantity of gas can be generated from the material being blended. However, the exhaust device The mixing chamber is designed so that the inner end of the exhaust device faces the mixing compartment. Therefore, the gas present in the mixing compartment can be vented outside the mixing chamber through the exhaust device. Thus, even when mixing a material that generates a large amount of gas, it is possible to suppress an increase in the internal pressure of the mixing chamber, allowing such a material to be mixed effectively.

[0063] When the weight is in the lower position, a gap can be formed between the weight and the peripheral edge of the upper opening of the mixing compartment, allowing the gas generated from the material to be mixed to escape from the mixing compartment into the internal space of the material inlet. In this case, if the amount of gas generated by the material to be mixed is small, simply venting the gas through the gap may be sufficient. However, if a large amount of gas is generated by the material to be mixed, simply venting the gas through the gap is not sufficient to prevent a pressure increase in the mixing compartment. Therefore, degassing by the exhaust device can prevent an increase in the internal pressure of the mixing compartment.

[0064] The mixing chamber may comprise a cylindrical chamber body having an opening at the top, and a pair of end plates that close the openings at both ends of the chamber body. In this case, the exhaust device may be provided on at least one of the pair of end plates. The mixing compartment may have a mixing zone at a position corresponding to the pair of mixing rotors and an adjacent zone at a position axially offset from the mixing zone. The inner end portion of the exhaust device may face the adjacent zone.

[0065] In this aspect, the exhaust device is provided on at least one end plate, and the inner end portion of the exhaust device is located in the adjacent area of ​​the mixing chamber. In the mixing chamber, the material to be mixed flows into the mixing zone when the mixing rotor rotates, but the material to be mixed is less likely to enter the adjacent area. Consequently, there is a small possibility that the flowing material to be mixed will come into contact with the inner end portion of the exhaust device. Thus, some of the material to be mixed can be prevented from entering the exhaust device, so that even if the exhaust device is provided in the mixing chamber, the exhaust device is less likely to be obstructed by the material to be mixed.

[0066] The inner end portion of the exhaust device may be located in a space situated above the pair of mixing rotors in the adjacent area.

[0067] In this aspect, the inner end portion of the exhaust device is less likely to come into contact with the material to be mixed. Consequently, during degassing by the exhaust device, the possibility of the material to be mixed becoming obstructed in the exhaust device at the same time as the vaporized component is evacuated can be further reduced. This configuration is therefore more suitable for degassing.

[0068] The escapement device can be provided in each of the pair of end plates.

[0069] In this embodiment, the exhaust device is provided on both end plates, and the inner end portion of the exhaust device is located in an adjacent area within the mixing chamber. In the mixing chamber, the material to be mixed flows into the mixing zone as the mixing rotor rotates. At this stage, there is a small possibility that the material to be mixed will enter the adjacent area. Consequently, there is a small possibility that the flowing material to be mixed will come into contact with the inner end portion of the exhaust device. Thus, it is possible to reduce the penetration of some of the material to be mixed into the exhaust device. Therefore, even though the exhaust device is provided within the mixing chamber, the exhaust device is less likely to become obstructed by the material to be mixed during degassing by the exhaust device.Furthermore, degassing can be carried out uniformly on both sides in the axial direction. Even if one exhaust device is obstructed, degassing can be carried out from the other exhaust device.

[0070] The exhaust device may include a cylindrical rod guide inserted into a through hole formed in at least one of the pair of end plates, a rod disposed in the rod guide, a vent orifice provided in the rod guide, a discharge passage provided in at least one of the pair of end plates so as to communicate with the vent orifice, and a cylinder that moves the rod so as to open and close the vent orifice via the rod. In this case, the inner end portion of the rod guide may constitute the inner end portion of the exhaust device located in the adjacent area.

[0071] In this aspect, since the venting orifice can be closed by the rod when venting is not required, any obstruction of the space in the rod guide can be eliminated. When venting is required, the venting orifice is opened by the rod, allowing venting from the peripheral surface of the rod guide.

[0072] A boss may be provided in an intermediate portion of the rod so as to be in contact with the rod guide. In the rod guide, an injection orifice for injecting liquid may be provided on the cylinder side relative to the vent orifice. In this case, the cylinder may be configured to move the rod so that the boss can assume a position in which it is located closer to the mixing chamber than to the injection orifice and a position in which it is located closer to the cylinder than to the injection orifice.

[0073] In this aspect, when the boss is located closer to the mixing chamber than to the injection port, it is possible to prevent the injection port from being blocked by the material to be mixed in the mixing chamber. Furthermore, a liquid, such as oil, injected through the injection port can spread into the rod guide due to the movement of the boss accompanying the movement of the rod. Additionally, when the boss is located on the cylinder side relative to the injection port, it is possible to clear an object obstructing the space in the rod guide into the mixing chamber by injecting the liquid. Moreover, if it is necessary to introduce a liquid during mixing, the liquid can be introduced into the mixing chamber via the exhaust device.Furthermore, since it is not necessary to provide an injection mechanism on the end plates separately from the exhaust device, it is possible to avoid increasing the number of end plate processing steps.

[0074] The exhaust device may include a through hole formed in at least one of the pair of end plates and comprising an inner end portion functioning as the inner end portion of the exhaust device, a rod inserted into the through hole, an exhaust passage provided in at least one of the pair of end plates so as to bifurcate from the through hole, and a cylinder configured to move the rod. In this case, when the distal end surface of the rod closes the inner end portion of the through hole, the distal end surface of the rod can be aligned with the inner surface of the mixing chamber facing the mixing compartment.

[0075] In this aspect, the inner end portion of the through hole is closed by the distal end surface of the rod, thus preventing the material to be mixed from entering and obstructing the through hole. When the distal end surface of the rod closes the inner end portion of the through hole, the rod can be prevented from interfering with the mixing of the material to be mixed.

[0076] The mixing chamber may include a cylindrical chamber body having the upper opening and a pair of end plates that close the openings at both ends of the chamber body, and the mixing compartment may include A mixing zone is located at a position corresponding to the pair of mixing rotors, and an adjacent zone is located at a position axially offset from the mixing zone. In this case, the exhaust device can be provided within the cylindrical chamber body so that the inner end portion of the exhaust device faces the adjacent zone.

[0077] In this aspect, the exhaust device is provided within the chamber body such that the inner end portion of the exhaust device faces the adjacent area. In the mixing compartment, the material to be mixed flows into the mixing zone as the mixing rotor rotates. At this stage, there is a low possibility that the material to be mixed will enter the adjacent area. Consequently, the possibility of the flowing material to be mixed coming into contact with the inner end portion of the exhaust device is reduced. Thus, some of the material to be mixed can be prevented from entering the exhaust device, so that, even though the exhaust device is provided within the mixing chamber, the exhaust device is less likely to be obstructed by the material to be mixed.

[0078] As described above, a kneadable material, in which a large quantity of gas, such as steam, is generated, can be kneaded.

Claims

Demands

1. Internal mixer comprising: a mixing chamber having a mixing compartment with a top opening; a material inlet portion located above the mixing chamber, having an internal space communicating with the mixing compartment, and configured to be able to introduce material from a material to be mixed into the internal space; a weight expected in the interior space; a drive device configured to move the weight up and down between a lower position and a retraction position, the lower position being a position in which the weight enters the mixing compartment and is able to press the material to be mixed into the mixing compartment from above, and the retraction position being a position in which the weight withdraws from the lower position to open the mixing compartment; a pair of mixing rotors configured to knead the material to be mixed in the mixing compartment; and an exhaust device having an inner end portion facing the mixing compartment and provided in the mixing chamber, the exhaust device being configured to vent the gas generated during the mixing of the material to be mixed from the inner end portion to the outside of the mixing chamber.

2. Internal mixer according to claim 1, wherein The mixing chamber comprises a cylindrical chamber body having an upper opening and a pair of end plates that close the openings at both ends of the chamber body; the exhaust device is provided on at least one of the pair of end plates. The mixing compartment comprises a mixing zone at a position corresponding to the pair of mixing rotors and an adjacent zone at a position axially offset from the mixing zone, and the inner end part of the exhaust device faces the adjacent area.

3. Internal mixer according to claim 2, wherein the inner end portion of the exhaust device is located in a space situated above the pair of mixing rotors in the adjacent area.

4. Internal mixer according to claim 2, wherein the exhaust device is provided in each of the pair of end plates.

5. Internal mixer according to claim 2, wherein the exhaust device comprises a cylindrical rod guide inserted in a through hole formed in at least one of the pair of end plates, a rod disposed in the rod guide, a vent orifice provided in the rod guide, an exhaust passage provided in at least one of the pair of end plates so as to communicate with the vent orifice, and a cylinder which moves the rod so as to open and close the vent orifice by the rod, and an inner end portion of the rod guide constitutes the inner end portion of the exhaust device located in the adjacent area.

6. Internal mixer according to claim 5, wherein a boss is provided in an intermediate part of the rod so as to be in contact with the rod guide, an injection orifice for injecting a liquid is provided in the rod guide on the side of the cylinder relative to the degassing orifice, and the cylinder is configured to move the rod so that the boss can take a state in which it is located closer to the mixing compartment than the injection orifice and a state in which it is located closer to the cylinder than the injection orifice.

7. Internal mixer according to claim 1, wherein the exhaust device comprises a through hole formed in at least one of the pair of end plates and comprising an inner end portion functioning as the inner end portion of the exhaust device, a rod inserted in the through hole, an exhaust passage provided in at least one of the pair of end plates so as to bifurcate from the through hole, and a cylinder configured to move the rod, and when the distal end surface of the rod closes the inner end portion of the through hole, the distal end surface of the rod is aligned with an inner surface of the mixing chamber facing the mixing compartment.

8. Internal mixer according to claim 1, wherein the mixing chamber comprises a cylindrical chamber body having the upper opening and a pair of end plates which close the openings at both ends of the chamber body, the mixing chamber comprises a mixing zone at a position corresponding to the pair of mixing rotors and an adjacent zone at a position axially offset from the mixing zone, and the exhaust device is provided in the chamber body such that the inner end portion of the exhaust device faces the adjacent zone.

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