Mixing machine

Abstract

To provide a mixing mill (1) that can suppress the deterioration of the physical properties of the mixture and has high sealing performance in the shaft portion of the rotor. The mixing mill (1) includes: a chamber (2) defining a mixing space (15), a rotor (3) including a first rotor shaft portion (12) and a second rotor shaft portion (13), a first bearing portion (4) rotatably supporting the first rotor shaft portion (12), a second bearing portion (5) rotatably supporting the second rotor shaft portion (13), and sealing materials (6a, 6b) that suppress leakage of working fluid at a position closer to the motor than the chamber (2). At least one of the first bearing portion (4) and the second bearing portion (5) is composed of an unlubricated bearing.

Description

Mixer The present invention relates to a mixer for mixing materials in the presence of a working fluid in a supercritical state or a subcritical state. Patent Document 1 discloses a kneading machine comprising a kneading rotor and a pair of bearings for kneading materials. The bearings rotatably support the kneading rotor at each of its axial ends. Lubricant oil derived from a resource other than petroleum is used in each of the pair of bearings. The kneading process can be carried out in the presence of a supercritical or subcritical working fluid. The kneading machine used in this situation requires a highly airtight chamber. In particular, the shaft of the kneading rotor must have a high degree of sealing performance. Furthermore, the kneading machine of Patent Document 1 is made of resources other than petroleum, and the aforementioned lubricating oil may mix into the material and cause the physical properties of the kneaded product to deteriorate. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-234077 [Problems to be Solved by the Invention] The object of the present invention is to provide a kneading machine that can suppress the degradation of the physical properties of the kneaded material and has high sealing performance on the shaft of the rotor. [Technical Means for Solving the Problems] Provided is a kneading machine for kneading materials in the presence of a working fluid in a supercritical or subcritical state, the kneading machine comprising: a chamber, a rotor, a first bearing, a second bearing, and a sealing material. The chamber defines a kneading space for kneading materials. The rotor comprises: a first rotor shaft, a rotor body, and a second rotor shaft arranged along the rotor axis. The first rotor shaft is one end portion of the rotor axis and is connected to a motor. The second rotor shaft is the other end portion of the rotor axis. The rotor body is located between the first and second rotor shafts and performs kneading by rotating within the kneading space. The first bearing rotatably supports the first rotor shaft. The second bearing rotatably supports the second rotor shaft. The sealing material is arranged so as to suppress leakage of the working fluid from the chamber toward the motor at a position closer to the motor than the chamber. At least one of the first bearing portion and the second bearing portion is formed of a non-lubricating bearing that does not contain lubricating oil. Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG1 shows a kneading device 20 including a kneading machine 1 according to a first embodiment of the present invention. The kneading machine 1 kneads materials in the presence of a working fluid in a supercritical or subcritical state. While the materials described in each embodiment are rubber, they may also be resins, foods, or the like. The kneading device 20 performs batch kneading. The supercritical state is a state where the temperature is above the critical temperature Tc of the working fluid and the pressure is above the critical pressure Pc of the working fluid. The subcritical state is a state close to the supercritical state. Examples of the conditions for the temperature T and pressure P of the subcritical state are shown below. The units of temperature T and critical temperature Tc in each example are all in Celsius. [Condition Example 1] The temperature T is above the critical temperature Tc and the pressure P is less than the critical pressure Pc (T≧Tc and P<Pc). [Condition Example 2] The temperature T is less than the critical temperature Tc and the pressure P is less than the critical pressure Pc (T<Tc and P<Pc), and the temperature T is significantly higher than room temperature and the pressure P is significantly higher than normal pressure (atmospheric pressure). [Condition Example 3] The ratio of temperature T to critical temperature Tc is greater than 0.5 and less than 1.0 (0.5<T / Tc<1.0), and the ratio of pressure P to critical pressure Pc is less than 0.5 (0.5<P / Pc). [Conditional Example 4] The ratio of temperature T to critical temperature Tc is less than 0.5 (0.5 < T / Tc), and the ratio of pressure P to critical pressure Pc is greater than 0.5 and less than 1.0 (0.5 < P / Pc < 1.0). [Conditional Example 5] When the critical temperature Tc is 0°C or lower, the ratio of pressure P to critical pressure Pc is less than 0.5 (0.5 < P / Pc). Examples of substances constituting the working fluid include carbon dioxide, nitrogen, hydrogen, xenon, ethane, ammonia, methanol, and water. Among them, carbon dioxide and nitrogen are suitable for rubber mixing. In this embodiment, carbon dioxide (CO 2) As a working fluid, carbon dioxide in a supercritical state (supercritical CO 2) Kneading in the presence of a working fluid. The kneading machine of the present invention is also suitable for kneading in the presence of other working fluids in a supercritical state or in the presence of a working fluid in a subcritical state. The kneading device 20 includes a production section 21 and a kneading section 22 . The production unit 21 produces supercritical CO 2. The production unit 21 includes a storage tank 31 , a first heat exchanger 32 , a pump 33 , and a second heat exchanger 34 . The storage tank 31 stores CO 2 gas. The first heat exchanger 32 converts the CO supplied from the storage tank 31 into 2 Gas cooled to liquid CO 2 is liquid CO 2. The pump 33 pumps liquid CO 2 pressurization. The aforementioned pump 33 pressurizes the liquid CO 2 The power required for pressurization is greater than that of the aforementioned pump 33 2 The power required for gas compression is small. The aforementioned pump 33 pressurizes the liquid CO 2Pump toward the downstream side. The second heat exchanger 34 is used to heat the pressurized liquid CO 2 Heat the container to allow liquid CO 2 gasification to make CO 2 becomes supercritical CO 2. The kneading section 22 is in supercritical CO The kneading section 22 includes the kneading machine 1 , a regulating valve 42 , and a separation filter 43 . In the flow path connecting the production section 21 and the kneading section 22, supercritical CO 2. Add materials and additives. 2 and added to supercritical CO 2 and the aforementioned materials and additives are introduced into the aforementioned kneading machine 1. The mixer 1 is heated in supercritical CO 2. The above materials and the above additives are kneaded in the presence of supercritical CO 2, thereby mixing quickly. When the material is a polymer material such as rubber or resin, the additive may be an additive, compounded rubber, or a plant-derived material including cellulose nanofiber. When the material is a food, the additive may be a food additive. The addition of the additive is optional. When the kneading in the kneading machine 1 is completed, the kneaded product of the above-mentioned materials and the above-mentioned additives is mixed with supercritical CO 2. Separation. The above-mentioned mixed material and supercritical CO 2 are discharged from the aforementioned mixer 1. The aforementioned regulating valve 42 adjusts the supercritical CO discharged from the aforementioned mixer 1. In this embodiment, the regulating valve 42 discharges the supercritical CO from the kneading machine 1. 2Decompression into CO 2 gas. The aforementioned separation filter 43 will be left in the CO 2 Additives in the gas from the CO 2Gas separation. The kneading device 20 further includes a return flow path 23. The return flow path 23 allows the CO separated from the kneaded product generated by kneading the materials to be returned to the kneaded product. 2 gas flows in the aforementioned return flow path 23, and the CO 2 gas is guided toward the upstream side of the first heat exchanger 32. Specifically, the return flow path 23 has an upstream end and a downstream end. The upstream end is connected to the separation filter 43 of the kneading section 22, and the downstream end is connected to the flow path connecting the storage tank 31 and the first heat exchanger 32. The return flow path 23 can return the CO separated from the kneaded material in the kneading section 22 to the The gas returns to the production section 21 through the return flow path 23, thereby allowing the CO separated from the kneaded product to be 2. Gas recycling. The overall structure of the kneading device 20 shown in Figure 1 is the same as that of the second embodiment and subsequent embodiments described later. However, the specific structure of the kneading device including the kneader of the present invention is not limited to the structure shown in Figure 1. As shown in FIG. 2 , the kneading machine 1 of the first embodiment includes a chamber 2 , a pair of rotors 3 , a pair of lubricated bearings 4 , a pair of non-lubricated bearings 5 ​​, a pair of first seals 6 a , a pair of second seals 6 b , and a pair of bearing supports 7 . The chamber 2 defines a kneading space 15, and the kneading of the materials is performed in the kneading space 15. The kneading machine 1 further includes a pair of supply and discharge ports 16 for connecting the kneading space 15 with the outside of the kneading machine 1. In this embodiment, the pair of supply and discharge ports 16 are fixed near the boundary between the chamber 2 and the pair of bearing support parts 7, which will be described in detail later. The supply and discharge ports 16 allow supercritical CO to be supplied to the kneading space 15 through the supply and discharge ports 16. 2. The supply and discharge port 16 allows the supercritical CO in the mixing space 15 to be discharged through the supply and discharge port 16. 2 is discharged to the outside of the aforementioned chamber 2. The chamber 2 includes a chamber body 2a, a pair of threaded portion receiving portions 2b, and a lid member 8. The chamber body 2a has a generally cylindrical sidewall surrounding the kneading space 15 and an end wall partially closing one of its two axial ends. The end wall is formed with a pair of through-holes that allow each of the pair of rotors 3 to pass through the end wall. The rotor axial direction is parallel to the pair of rotors 3 and is the vertical direction on the paper of Figure 2. The pair of threaded portion receiving portions 2b are arranged in a direction perpendicular to the rotor axial direction and are connected to the end wall of the chamber body 2a so as to communicate with the kneading space 15 through the pair of through-holes. The other of the two axial ends of the chamber body 2a (the lower end in Figure 2) is fully open, forming an opening that opens to the kneading space 15. The lid member 8 is removably attached to the chamber body 2a to close the opening. Each of the pair of bearing supports 7 is cylindrical and connected to the pair of threaded portion receiving portions 2b of the chamber 2 so as to extend from the pair of threaded portion receiving portions 2b toward the side opposite to the cover member 8. In other words, the cover member 8 is attached to the chamber body 2a on the side opposite to the pair of bearing supports 7 across the chamber body 2a. The pair of rotors 3 extend in parallel with each other in the rotor axial direction and are rotatably supported by the cover member 8 of the chamber 2 and the pair of bearing support portions 7. By the rotation of each rotor in the pair of rotors 3, supercritical CO 2, the materials in the kneading space 15 are kneaded. Each of the pair of rotors 3 includes a rotor body 11, a first rotor shaft 12, a second rotor shaft 13, a first threaded portion 14A, and a second threaded portion 14B, arranged along a straight line extending in the rotor's axial direction. The rotor body 11 is disposed within the kneading space 15. The rotor body 11 has spiral teeth (not shown). These teeth are shaped so that the rotor body 11 rotates within the kneading space 15 to knead the material. The first rotor shaft 12 and the second rotor shaft 13 are located on either side of the rotor body 11 in the rotor axial direction. The first rotor shaft 12 is one end of the rotor 3 in the rotor axial direction, and the second rotor shaft 13 is the other end of the rotor 3 in the rotor axial direction. The first rotor shaft 12 and the second rotor shaft 13 extend in the rotor axial direction. The first rotor shaft 12 is rotatably supported by the bearing support portion 7 via the lubricated bearing 4. The second rotor shaft 13 is rotatably supported by the chamber 2, specifically, by the cover member 8, via the non-lubricated bearing 5. A motor (not shown) is connected to the end of the first rotor shaft 12 to rotate the rotor 3. The first threaded portion 14A is interposed between the rotor body 11 and the first rotor shaft 12, and is received with an appropriate clearance in the corresponding threaded portion receiving portion 2b of the pair of threaded portion receiving portions 2b. The second threaded portion 14B is interposed between the rotor body 11 and the second rotor shaft 13, and a portion of the second threaded portion 14B is received with an appropriate clearance in a threaded portion receiving recess 8b formed on the inner side surface of the cover member 8. Both the first threaded portion 14A and the second threaded portion 14B have outer circumferential surfaces formed with threads. The helical direction of the threads of the first threaded portion 14A is set so as to push the kneaded material, which is intended to move toward the first rotor shaft 12 as the rotor 3 rotates, back toward the rotor body 11. The helical direction of the threads of the second threaded portion 14B is opposite to the helical direction of the threads of the first threaded portion 14A, and is a direction that can push the kneaded material that attempts to move toward the second rotor shaft 13 as the rotor 3 rotates back toward the rotor body 11. Therefore, the first threaded portion 14A can prevent the kneaded material from moving toward the lubricated bearing 4, and the second threaded portion 14B can prevent the kneaded material from moving toward the non-lubricated bearing 5. The lubricating bearing 4 is a bearing lubricated with lubricating oil and constitutes a first bearing portion that rotatably supports the first rotor shaft 12. Specifically, the lubricating bearing 4 is disposed inside the bearing support portion 7 and is supported by the bearing support portion 7 to rotatably support the first rotor shaft 12. The lubricating bearing 4 is, for example, a rolling bearing. The non-lubricated bearing 5 is a bearing that contains no lubricating oil, that is, a bearing that is not lubricated with lubricating oil, and constitutes a second bearing portion that rotatably supports the second rotor shaft 13. The non-lubricated bearing 5 is disposed within the cover member 8 and is held by the cover member 8, rotatably supporting the end portion of the second rotor shaft 13. Therefore, the second rotor shaft 13 does not penetrate the cover member 8 but is instead restrained within the cover member 8. The non-lubricated bearing 5 is, for example, a metal bushing. The kneading machine 1 of this embodiment further includes a pair of protective members 9. Each of the pair of protective members 9 is cylindrical and is disposed around the first rotor shaft 12 at a position closer to the rotor body 11 than the lubricating bearing 4, covering the entire circumference of the outer circumference of the first rotor shaft 12. Specifically, the protective members 9 are interposed between the outer circumference of the first rotor shaft 12 and the inner circumference of each of the pair of bearing support portions 7. The protective members 9 rotate along with the first rotor shaft 12 as the rotor 3 rotates. On the other hand, the first rotor shaft 12 is configured to be separable from a portion of the rotor 3 adjacent to the first rotor shaft 12 (in the present embodiment, the first threaded portion 14A). This separation enables the protective member 9 to be removed from between the bearing support portion 7 and the first rotor shaft 12 into the chamber 2 along the rotor axial direction, and enables the protective member 9 to be inserted from the chamber 2 into between the bearing support portion 7 and the first rotor shaft 12 along the rotor axial direction. The pair of first seals 6a and the pair of second seals 6b are respectively disposed inside the pair of bearing support portions 7 and are configured to suppress (inhibit) fluid leakage through the gaps within the bearing support portions 7. Therefore, the first and second seals 6a, 6b suppress leakage of the working fluid from the chamber 2 toward the motor, that is, from the second rotor shaft 13 toward the first rotor shaft 12, at a position closer to the motor than the chamber 2. Furthermore, the first and second seals 6a, 6b suppress leakage of fluid (e.g., lubricating oil) toward the chamber 2 from the side closer to the motor than the seals 6a, 6b. The first and second seals 6a, 6b are disposed within the bearing support portion 7 closer to the chamber 2 than the lubricating bearing 4, that is, between the lubricating bearing 4 and the chamber 2. The first sealing member 6a is annular and interposed between the outer circumference of the first rotor shaft 12 and the inner circumference of the protective member 9. The first sealing member 6a is, for example, a single-pressure seal with an internal spring. The first sealing member 6a is embedded in an annular groove formed in the inner circumference of the protective member 9. The kneading machine 1 may also include a plurality of first sealing members 6a arranged along the rotor axial direction. The second sealing member 6b is annular and interposed between the outer circumference of the protective member 9 and the inner circumference of the bearing support portion 7. The second sealing member 6b is, for example, an O-ring. The second sealing member 6b is embedded in an annular groove formed in the outer circumference of the protective member 9. The outer circumferential surface of the protective member 9 contacts the second sealing material 6 b instead of the outer circumferential surface of the first rotor shaft 12, thereby protecting the outer circumferential surface of the first rotor shaft 12. As the rotor 3 rotates, the outer circumferential surface of the protective member 9 may slide relative to the second sealing material 6 b in the rotational direction. This sliding may accelerate wear damage to the outer circumferential surface of the protective member 9, resulting in a decrease in the sealing performance of the second sealing material 6 b. Therefore, the protective member 9 can be removed from the first rotor shaft 12 and replaced with a new one. In this case, the frequency of replacement of the first rotor shaft 12 can be significantly reduced compared to a case where the outer circumferential surface of the first rotor shaft 12 contacts the second sealing material 6 b. The second sealing member 6b is disposed in the rotor axial direction at a position opposite to the chamber 2 across the supply and discharge port 16. Specifically, the second sealing member 6b is disposed between the supply and discharge port 16 and the lubricating bearing 4. The kneading machine 1 may include a plurality of second sealing members 6b arranged along the rotor axial direction. By placing the first and second sealing members 6a, 6b between the lubricating bearing 4, which is lubricated with lubricating oil, and the chamber 2, leakage of the lubricating oil into the kneading space 15 of the chamber 2 can be suppressed, thereby preventing the lubricating oil from deteriorating the physical properties of the kneaded product. Furthermore, the first and second sealing members 6a, 6b can be easily replaced after the protective member 9 is removed from between the bearing support 7 and the first rotor shaft 12. On the other hand, since the non-lubricated bearing 5, which serves as the second bearing, does not contain lubricating oil, a sealant is not required between the non-lubricated bearing 5 and the chamber 2. This reduces the number of parts in the kneading machine 1, including the sealant. Furthermore, the use of the non-lubricated bearing 5 prevents degradation of the physical properties of the kneaded material within the kneading space 15 due to lubricating oil. FIG3 shows a modified example of the kneading machine 1 of the first embodiment. In this modified example, the protective member 9 shown in FIG2 is omitted from each of the pair of bearing supports 7. Furthermore, instead of the first and second seals 6a and 6b shown in FIG2 , a single annular third seal 6c is provided. The third seal 6c is in close contact with the outer circumference of the first rotor shaft 12 and the inner circumference of the bearing support 7, respectively, between the supply and discharge port 16 and the lubricating bearing 4. Like the first and second seals 6a and 6b, the third seal 6c can also seal between the chamber 2 and the lubricating bearing 4. The kneading machine 1 may also include a plurality of third seals 6c arranged along the rotor axis between the supply and discharge port 16 and the first bearing 4. In the kneading machine 1 described above, the first and second seals 6a, 6b shown in FIG. 2 , and the third seal 6c shown in FIG. 3 are all arranged to suppress leakage of the working fluid from the chamber 2 toward the motor at a location between the chamber 2 and the motor, thereby enhancing the sealing performance around the first rotor shaft 12. To connect to the motor, the first rotor shaft 12 must be arranged to penetrate a member (the bearing support portion 7 in the kneading machine 1 shown in FIG. 2 and FIG. 3 ) that receives the working fluid and extends between the chamber 2 and the motor. The first and second seals 6a, 6b, and third seal 6c all effectively prevent leakage of the working fluid from the chamber 2 toward the motor between the first rotor shaft 12 and the bearing support portion 7. Furthermore, the non-lubricated bearing 5 constituting the second bearing portion does not contain lubricating oil, thereby suppressing degradation of the physical properties of the kneaded product. Lubricating oil may potentially enter the kneaded product, thereby degrading the physical properties of the kneaded product. The second bearing portion is constituted by the non-lubricated bearing 5, thereby reducing the possibility of lubricating oil entering the kneaded product and suppressing degradation of the physical properties of the kneaded product. Furthermore, the non-lubricated bearing can have a simpler structure than a lubricated bearing such as a rolling bearing. This allows the kneading machine 1 to have a simpler structure than, for example, a case where both the first and second bearing portions include lubricated bearings. In this case, for example, maintenance of the kneading machine 1 is facilitated. On the other hand, the chamber 2 includes the chamber body 2a and the lid member 8. The chamber body 2a has an opening at its end, located in the rotor axial direction and closer to the second rotor shaft 13, that opens into the kneading space 15. The lid member 8 is removably attached to the chamber body 2a to seal the opening, making maintenance easier through the opening. Furthermore, the aforementioned non-lubricated bearing 5, serving as the second bearing, is positioned within the lid member 8 and supports the end of the second rotor shaft 13. The second rotor shaft 13 can be supported without penetrating the lid member 8. In this case, there is no need to arrange a seal around the second rotor shaft 13 to prevent leakage of the working fluid from the chamber 2. This reduces the number of parts in the kneading machine 1, including the seal. Consequently, the kneading machine 1 can have a simple structure, making maintenance easier. Furthermore, since a sealing material is not required between the non-lubricated bearing 5 and the chamber 2, the distance between the lubricated bearing 4 constituting the first bearing portion and the non-lubricated bearing 5 constituting the second bearing portion can be shortened, thereby suppressing eccentricity of the rotor 3. Thus, bearing seizure and the like caused by eccentricity of the rotor 3 can be suppressed. On the other hand, the first and second sealing materials 6a and 6b shown in FIG2 and the third sealing material 6c shown in FIG3 are respectively arranged between the lubricating bearing 4 and the chamber 2 to suppress leakage of fluid from the motor into the chamber 2, thereby suppressing leakage of lubricating oil from the lubricating bearing 4 into the kneading space 15 of the chamber 2. In this case, the lubricating oil can be prevented from mixing into the kneaded product, thereby suppressing the lubricating oil from causing deterioration of the physical properties of the kneaded product. In general, lubricated bearings are less susceptible to wear and have a longer lifespan than non-lubricated bearings. Since the first bearing portion is composed of the lubricated bearing 4, the frequency of maintenance work on the first bearing portion may be reduced. FIG4 shows a kneading machine 101 according to a second embodiment of the present invention. The kneading machine 101 is provided with a non-lubricated bearing 51 in addition to the components of the kneading machine 1 shown in FIG3 . The non-lubricated bearing 51 and the lubricated bearing 4 are arranged together on the inner side of the bearing support portion 7 to constitute a first bearing portion. That is, the non-lubricated bearing 51 and the lubricated bearing 4 together rotatably support the first rotor shaft 12 at a position between the third sealing material 6c and the chamber 2 in the bearing support portion 7. The non-lubricated bearing 51 is located between the chamber 2 and the lubricated bearing 4. Furthermore, the non-lubricated bearing 51 is located between the supply and discharge port 16 and the lubricated bearing 4 in the axial direction of the rotor. Similar to the kneading machine 1 shown in FIG3 , the kneading machine 101 does not include the protective member 9 shown in FIG2 . Instead, the seal material of each bearing support portion 7 comprises only the annular third seal material 6 c. The third seal material 6 c is positioned between the lubricated bearing 4 and the non-lubricated bearing 51 in the rotor axial direction. The kneading machine 101 may also include a plurality of third seal materials 6 c arranged along the rotor axial direction between the lubricated bearing 4 and the non-lubricated bearing 51. The non-lubricated bearing 51 is positioned closer to the chamber 2 than the lubricated bearing 4 and, together with the lubricated bearing 4, forms the aforementioned first bearing portion that rotatably supports the first rotor shaft 12. This prevents eccentricity of the rotor 3 and, consequently, bearing meltdown and other issues. Furthermore, because the non-lubricated bearing 51 is positioned closer to the chamber 2 than the third seal 6c, the distance between the non-lubricated bearing 51 and the second bearing portion (the non-lubricated bearing 5 in FIG. 4 ) is shortened, effectively suppressing eccentricity of the rotor 3. Furthermore, because the non-lubricated bearing 51 does not contain lubricating oil, even though the non-lubricated bearing 51 is positioned closer to the chamber 2 than the third seal 6c, degradation of the physical properties of the kneaded material within the kneading space 15 of the chamber 2 due to lubricating oil is prevented. Fig. 5 shows a kneading machine 201 according to a third embodiment of the present invention. In the kneading machine 201, the first bearing portion of each of the pair of bearing support portions 7 includes only a non-lubricated bearing 51 and does not include a lubricated bearing (such as the lubricated bearing 4 shown in Fig. 3). The kneading machine 201, like the kneading machine 101 of the second embodiment, does not include the protective member 9 shown in FIG2 , but instead includes only an annular third sealing member 6c as a sealing member. The third sealing member 6c is positioned on the side of the non-lubricated bearing 51 opposite the chamber 2, i.e., closer to the motor than the non-lubricated bearing 51. The kneading machine 201 may also include a plurality of third sealing members 6c arranged along the rotor axis between the non-lubricated bearing 51 and the motor. Furthermore, the third sealing member 6c may be positioned closer to the chamber 2 than the non-lubricated bearing 51. The first bearing portion of the kneading machine 201 may further include, in addition to the non-lubricated bearing 51, a non-lubricated bearing disposed between the supply and discharge port 16 and the non-lubricated bearing 51, or between the non-lubricated bearing 51 and the third sealing member 6c. Increasing the number of bearings supporting the shaft of the rotor 3 can more effectively suppress eccentricity of the rotor 3, thereby more effectively preventing bearing melting caused by the eccentricity. While the embodiments of the present invention have been described above, these are merely examples and are not intended to limit the present invention. The specific configurations and other aspects may be modified as appropriate. Furthermore, the functions and effects described in the embodiments of the present invention are merely examples of the best functions and effects produced by the present invention, and the functions and effects of the present invention are not limited to those described in the embodiments of the present invention. For example, the first bearing, second bearing, and seal material provided in each of the pair of rotors 3 shown in Figures 2 to 5 may have the same or different configurations. For example, when the first rotor shaft 12 of only one of the pair of rotors 3 is connected to the motor, the first bearing supporting the first rotor shaft 12 connected to the motor may include only the lubricated bearing 4, while the first bearing supporting the first rotor shaft 12 not connected to the motor may include only a non-lubricated bearing. When the first bearing portion is composed of a non-lubricated bearing (e.g., the non-lubricated bearing 51 shown in FIG4 ), the second bearing portion may also include a lubricated bearing. In this case, preferably, a sealing material is disposed between the lubricated bearing included in the second bearing portion and the chamber 2 . The present invention is not limited to the kneading machine including the pair of rotors 3 described above, but can also be applied to a kneading machine including only a single rotor. As described above, a kneading machine is provided that can suppress the deterioration of the physical properties of the kneaded material, and the shaft portion of the rotor has high sealing performance. The kneading machine kneads the materials in the presence of a working fluid in a supercritical state or a subcritical state. The kneading machine comprises: a chamber, a rotor, a first bearing portion, a second bearing portion, and a sealing material. The chamber defines a kneading space for kneading the materials. The rotor comprises: a first rotor shaft portion, a rotor body, and a second rotor shaft portion arranged along the rotor axis. The first rotor shaft portion is one end portion of the rotor axis and is connected to the motor. The second rotor shaft portion is the other end portion of the rotor axis. The rotor body is located between the first rotor shaft portion and the second rotor shaft portion, and performs the kneading by rotating in the kneading space. The first bearing portion rotatably supports the first rotor shaft. The second bearing portion rotatably supports the second rotor shaft. The sealing material is positioned closer to the motor than the chamber to suppress leakage of the working fluid from the chamber toward the motor. At least one of the first bearing and the second bearing is a non-lubricated bearing that does not contain lubricating oil. This kneading machine has high sealing performance and can suppress degradation of the physical properties of the kneaded material kneaded in the kneading space. The kneading machine may be configured such that both the first bearing portion and the second bearing portion include the non-lubricated bearing. This can more reliably suppress the degradation of the material's physical properties due to the lubricating oil. The chamber may also include a chamber body and a cover member. The chamber body has an opening at one of the two axial ends of the rotor, the end closest to the second rotor shaft, that opens to the kneading space. The cover member is mounted on the chamber body to close the opening. In this case, the second bearing portion preferably comprises the non-lubricated bearing, and the non-lubricated bearing is fixed to the cover member. This ensures high airtightness within the kneading space and prevents degradation of the physical properties of the kneaded material within the kneading space due to lubricating oil. The first bearing portion may also include a lubricating bearing lubricated with lubricating oil. In this case, the sealing member is disposed between the lubricating bearing and the chamber to suppress leakage of fluid from the lubricating bearing into the chamber. Even when the lubricating bearing is used, the sealing member can still suppress leakage of lubricating oil from the lubricating bearing into the kneading space within the chamber. Alternatively, the first bearing portion may include the non-lubricated bearing, and the non-lubricated bearing may be disposed between the sealing material and the chamber. This arrangement of the non-lubricated bearing can suppress degradation of the kneaded product's physical properties due to lubricating oil, and can shorten the distance between the non-lubricated bearing and the second bearing portion, thereby suppressing eccentricity of the rotor. 1,101,201: Kneading machine 2: Chamber 2a: Chamber body 2b: Threaded portion receiving portion 3: Rotor 4: Lubricated bearing 5, 51: Non-lubricated bearing 6a: First sealing material 6b: Second sealing material 6c: Third sealing material 7: Bearing support portion 8: Cover member 8b: Threaded portion receiving recess 9: Protective member 11: Rotor body 12: First rotor shaft 13: Second rotor shaft 14A: First threaded portion 14B: Second threaded portion 15: Kneading space 16: Supply and discharge port 20: Kneading device 21: Manufacturing portion 22: Kneading portion 23: Return flow path 31: Storage tank 32: First heat exchanger 33: Pump 34: Second heat exchanger 42: Adjustment valve 43: Separation filter FIG1 is a flow chart showing a kneading apparatus according to various embodiments of the present invention. FIG2 is a cross-sectional view of a kneading machine according to the first embodiment of the present invention. FIG3 is a cross-sectional view of a kneading machine according to a modified example of the first embodiment. FIG4 is a cross-sectional view of a kneading machine according to the second embodiment of the present invention. FIG5 is a cross-sectional view of a kneading machine according to the third embodiment of the present invention. 1: Mixing machine 2: Chamber 2a: Chamber body 2b: Threaded portion receiving portion 3: Rotor 4: Lubricate the bearings 5: Non-lubricated bearings 6a: 1st sealing material 6b: Second sealing material 7: Bearing support 8: Cover member 8b: Threaded portion receiving recess 9: Protective components 11: Rotor body 12: 1st rotor shaft 13: Second rotor shaft 14A: 1st thread 14B: Second thread 15: Mixing space 16: Supply and discharge port

Claims

1. A mixing machine for mixing materials in the presence of a working fluid in a supercritical or subcritical state, the mixing machine comprising: a chamber, a rotor, a first bearing portion, a second bearing portion, and a sealing material; the chamber defining a mixing space for mixing the materials; the rotor comprising: a first rotor shaft portion, a rotor body, and a second rotor shaft portion arranged along the rotor axis; the first rotor shaft portion being one end of the rotor shaft in the axial direction and connected to a motor; the second rotor shaft portion being the other end of the rotor shaft in the axial direction; the rotor body being located between the first rotor shaft portion and the second rotor shaft portion and performing the mixing by rotating within the mixing space; the first bearing portion rotatably supporting the first rotor shaft portion; the second bearing portion rotatably supporting the second rotor shaft portion; and the sealing material configured to suppress leakage of the working fluid from the chamber toward the motor at a position closer to the motor than the chamber. At least one of the aforementioned first bearing portion and the aforementioned second bearing portion is constituted by an unlubricated bearing without lubricating oil. The aforementioned chamber includes a chamber body and a cover member. The aforementioned chamber body has an opening at the end near the aforementioned second rotor shaft portion of the two ends of the aforementioned rotor axial direction, which opens the aforementioned mixing space. The aforementioned cover member is installed on the aforementioned chamber body in a manner that closes the aforementioned opening. The aforementioned second bearing portion is constituted by the aforementioned unlubricated bearing. The aforementioned unlubricated bearing is fixed to the aforementioned cover member and disposed inside the aforementioned cover member. The aforementioned cover member holds and rotatably supports the end of the aforementioned second rotor shaft portion, thereby confining the aforementioned second rotor shaft portion inside the aforementioned cover member without penetrating the aforementioned cover member. The aforementioned sealing material is disposed only in the aforementioned first rotor shaft portion and the aforementioned second rotor shaft portion.

2. As in request item 1, the mixing machine, wherein, Both the aforementioned first bearing section and the aforementioned second bearing section include the aforementioned unlubricated bearing.

3. As in request item 1, the mixing machine, wherein, The aforementioned first bearing portion includes a lubricated bearing lubricated with lubricating oil, and the aforementioned sealing material is configured to suppress fluid leakage from the aforementioned lubricated bearing to the aforementioned chamber at a position between the aforementioned lubricated bearing and the aforementioned chamber.

4. As in request item 1, the mixing machine, wherein, The aforementioned first bearing portion includes the aforementioned unlubricated bearing, which is disposed between the aforementioned sealing material and the aforementioned chamber.

Images