Closed mixer

Abstract

Provided is an enclosed kneader that can reduce the amount of lubricating oil supplied to a leakage prevention part while reducing wear of the leakage prevention part. 【Solution means】During a material intake period in which the kneaded material is likely to leak from the leakage prevention part 100, in order to increase the supply amount R of the lubricating oil supplied to the leakage prevention part 100, it is possible to reduce wear of the leakage prevention part while suppressing leakage of the kneaded material from the leakage prevention part 100. Further, during a period other than the material intake period, since the kneaded material is less likely to leak compared to the material intake period, the supply amount R of the lubricating oil can be reduced by reducing the supply amount R of the lubricating oil supplied to the leakage prevention part 100 during this period.

Description

Technical Field

[0001] The present disclosure relates to the supply of lubricating oil supplied to a leakage prevention portion of a closed kneader.

Background Art

[0002] A closed kneader for kneading kneaded materials such as rubber and plastic together with various additives is known. Patent Document 1 discloses such a closed kneader having a chamber and a pair of kneading rotors. The chamber forms a kneading chamber, and the pair of kneading rotors are arranged side by side in the kneading chamber and rotate. Shearing force is applied to the kneaded material between the pair of kneading rotors and the chamber, and the kneaded material is kneaded.

[0003] Further, in the technique described in Patent Document 1, a lubricating oil supply mechanism for supplying lubricating oil to a leakage prevention portion (also referred to as a seal portion) between the kneading rotor and the chamber is provided, and the temperature of the leakage prevention portion is measured during kneading of the kneaded material, and the supply amount of the lubricating oil is adjusted based on the measured temperature.

[0004] Further, in the technique described in Patent Document 2, a lubricating oil supply device for supplying lubricating oil to a leakage prevention portion between the kneading rotor and the chamber is provided, and the supply amount of the lubricating oil supplied to the leakage prevention portion is adjusted according to the rotation speed of the kneading rotor.

[0005] Further, in the technique described in Patent Document 3, a rotating side seal member that rotates integrally with the kneading rotor and a ring-shaped fixed side seal member that rotatably penetrates the rotor shaft of the kneading rotor are provided, and a lubricating oil supply mechanism for supplying lubricating oil between the fixed side seal member and the rotating side seal member is further provided.

[0006] Further, in the technique described in Patent Document 4, a lubricating oil supply mechanism for supplying lubricating oil to a leakage prevention portion between the kneading rotor and the chamber is provided, and during the standby mode in which the kneaded material is taken out from the chamber, the supply amount of the lubricating oil supplied from the lubricating supply mechanism is reduced compared to the case where there is a kneaded material in the chamber.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] The kneaders described in Patent Documents 1 to 4 above all suppress wear of the leakage prevention part by supplying lubricating oil to the leakage prevention part between the kneading rotor and the chamber. By the way, from the viewpoints of the environment and operation costs, it is desirable to reduce the supply amount of the lubricating oil supplied to the leakage prevention part. In contrast, for example, in the technique described in Patent Document 1, since a constant pressing pressure is always applied to the leakage prevention part, it is necessary to continuously supply a predetermined amount or more of lubricating oil to suppress wear of the leakage prevention part even under conditions where the pressing pressure is not required. Further, although the technique described in Patent Document 2 describes reducing the supply amount of lubricating oil until the maximum rotation speed of the kneading rotor reaches 50%, no consideration is given to reducing the supply amount of lubricating oil during a series of kneading steps of kneading the material to be kneaded. Further, although Patent Document 4 describes reducing the supply amount of lubricating oil during the standby mode in which the material to be kneaded is taken out from the chamber, no consideration is given to reducing the supply amount of lubricating oil during a series of kneading steps of kneading the material to be kneaded. Note that Patent Document 3 does not describe anything about adjusting the supply amount of lubricating oil.

[0009] An object of the present invention is to provide an enclosed kneader capable of reducing the supply amount of lubricating oil supplied to the leakage prevention part while reducing wear of the leakage prevention part.

Means for Solving the Problems

[0010] The inventors of the present invention have intensively studied the above problems, and found that during the material intake period when the material to be kneaded is taken into the chamber, the material to be kneaded is more likely to leak from the leakage prevention part compared to other periods in the kneading process of the material to be kneaded. On the other hand, during other periods other than the material intake period, the material to be kneaded is less likely to leak from the leakage prevention part, and even if the supply amount of the lubricating oil is small, it is sufficient. Based on this discovery, the present invention has been achieved.

[0011] The sealed kneader according to the first aspect includes a casing having a chamber for accommodating the material to be kneaded therein, a rotor shaft portion extending outside the chamber, and a kneading blade portion disposed inside the chamber. The kneading rotor rotates to knead the material to be kneaded in the chamber, a weight provided on the casing so as to be movable up and down to push the material to be kneaded introduced into the chamber, a leakage prevention part for preventing the material to be kneaded in the chamber from leaking to the outside of the chamber, and a lubricating oil supply mechanism for supplying lubricating oil to the leakage prevention part. The leakage prevention part includes a fixed-side seal member attached to the casing so as to surround the rotor shaft portion, and a rotating-side seal member attached to the rotor shaft portion so as to face the fixed-side seal member and rotatable while sliding with respect to the fixed-side seal member. The lubricating oil supply mechanism increases the supply amount of the lubricating oil supplied to the leakage prevention part during the material intake period when the material to be kneaded is taken into the chamber.

[0012] According to the first aspect, during the material intake period when the material to be kneaded is likely to leak from the leakage prevention part, the supply amount of the lubricating oil supplied to the leakage prevention part is increased. Therefore, it is possible to suppress the leakage of the material to be kneaded from the leakage prevention part and reduce the wear of the leakage prevention part. In addition, during the period other than the material intake period, since the material to be kneaded is less likely to leak compared to the material intake period, the supply amount of the lubricating oil can be reduced by reducing the supply amount of the lubricating oil supplied to the leakage prevention part during this period.

[0013] A second aspect preferably further has the following features in the closed kneader according to the first aspect. That is, the closed kneader according to the second aspect further includes a seal pressurizing mechanism that increases the pressure applied between the fixed-side seal member and the rotating-side seal member during the material intake period. According to the second aspect, during the material intake period, since the kneaded material is likely to leak from the leakage prevention portion, by increasing the pressure applied between the fixed-side seal member and the rotating-side seal member by the seal pressurizing mechanism during the material intake period, leakage of the kneaded material from the leakage prevention portion can be suppressed. Further, during the material intake period, since the supply amount of the lubricating oil supplied to the leakage prevention portion increases compared to other periods, even if the pressure between the fixed-side seal member and the rotating-side seal member increases, wear of the leakage prevention portion can be reduced.

[0014] A third aspect preferably further has the following features in the closed kneader according to the first or second aspect. That is, in the closed kneader according to the third aspect, the material intake period includes at least a part of the period during which the weight pushes the kneaded material among the period after the kneaded material is put into the chamber until the weight reaches a predetermined lower limit position. According to the third aspect, after the kneaded material is put into the chamber, during the period when the weight pushes the kneaded material among the period until the weight reaches the predetermined lower limit position, the kneaded material is most likely to leak from the leakage prevention portion. Therefore, by including at least a part of the above period in the material intake period, the supply amount of the lubricating oil to the leakage prevention portion in the kneading process of the kneaded material can be appropriately distributed, and the supply amount of the lubricating oil in the kneading process can be reduced.

[0015] A fourth aspect preferably further has the following features in the closed kneader according to any one of the first to third aspects. That is, in the closed kneader according to the fourth aspect, a seal interval measurement unit that measures the seal interval between the fixed-side seal member and the rotating-side seal member, and a material leakage warning unit that issues a warning when the seal interval measured by the seal interval measurement unit becomes a predetermined value or more are further provided. When the seal interval between the fixed-side seal member and the rotating-side seal member increases, there is a risk that the material to be kneaded leaks from the leakage prevention unit. In contrast, according to the fourth aspect, when the seal interval becomes a predetermined value or more, a warning is issued from the material leakage warning unit, so that a sign of leakage of the material to be kneaded can be detected.

[0016] A fifth aspect preferably further has the following features in the closed kneader according to any one of the second to fourth aspects. That is, the closed kneader according to the fifth aspect further includes a seal interval measurement unit that measures the seal interval between the fixed-side seal member and the rotating-side seal member, and when the seal interval measured by the seal interval measurement unit becomes a predetermined value or more, the seal pressure mechanism further increases the pressure applied between the fixed-side seal member and the rotating-side seal member. According to the fifth aspect, when it is detected that there is a risk that the material to be kneaded leaks from the leakage prevention unit based on the seal interval, the pressure between the fixed-side seal member and the rotating-side seal member is further increased, so that leakage of the material to be kneaded can be suppressed.

[0017] A sixth aspect is the closed kneader according to the second or fifth aspect, wherein the seal pressure mechanism has a pressing portion that presses the fixed-side seal member toward the rotating-side seal member, the lubricating oil supply mechanism has an oil injection port that penetrates the fixed-side seal member and supplies lubricating oil between the fixed-side seal member and the rotating-side seal member, and the oil injection port is formed near a portion of the fixed-side seal member that is pressed by the pressing portion. According to the sixth aspect, since the lubricating oil is supplied concentratedly to the portion of the fixed-side seal member and the rotating-side seal member that is likely to wear, the lubricating oil is efficiently supplied, and the supply amount of the lubricating oil can be further reduced.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide an enclosed kneader that can reduce the supply amount of lubricating oil supplied to the leakage prevention part while reducing the wear of the leakage prevention part.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0020] [Overall Structure] Hereinafter, with reference to the drawings, a kneader 1 (enclosed kneader) according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the kneader 1 according to the present embodiment. FIG. 2 is a front view showing a leakage prevention part 100 of the kneader 1. FIG. 3 is a perspective view schematically showing an oil supply structure to the leakage prevention part 100 of the kneader 1.

[0021] Referring to FIG. 1, the kneader 1 includes a pair of kneading rotors 2, a casing 3, a chamber 4, a weight 5, and a drop door 6. The chamber 4 is formed inside the casing 3 and is a space for accommodating the material to be kneaded, such as a polymer material, therein.

[0022] The pair of kneading rotors 2 knead the material to be kneaded in the chamber 4 by rotating. Each kneading rotor 2 has a rotor shaft portion 2A and a kneading blade portion 2B. The rotor shaft portion 2A extends outside the chamber 4 and is rotatably supported by the casing 3. The kneading blade portion 2B is disposed inside the chamber 4 and is a blade portion protruding radially outward from the rotor shaft portion 2A. The kneading blade portion 2B applies a shearing force to the material to be kneaded by rotation.

[0023] The inner wall surface of the casing 3 is formed in a comma shape in the longitudinal section shown in FIG. 1, and end plates 8 are joined to both side surfaces of the casing 3 in the direction orthogonal to the plane of the paper in FIG. 1 as shown in FIG. 2. As a result, the chamber 4 including a pair of left and right kneading chambers 4a is formed so as to be able to accommodate the material to be kneaded therein.

[0024] Also, an inlet 3a for charging the material to be kneaded into the chamber 4 is formed at the upper central portion of the casing 3. And a weight 5 for pushing the material to be kneaded charged into the chamber 4 through the inlet 3a of the casing 3 into the kneading chamber 4a of the chamber 4 is provided so as to be able to move up and down. On the other hand, a discharge port 3b is formed at the lower central portion of the chamber 4 so that the material to be kneaded in a desired kneaded state can be discharged to the outside, and a drop door 6 for opening and closing the discharge port 3b is provided. And these weight 5 and drop door 6 are configured to form a part of the inner wall surface of the chamber 4 by being in close contact with the casing 3 during kneading.

[0025] The weight 5 is configured to be movable up and down between a lower limit position Plow indicated by a solid line and an upper limit position Phi indicated by a two-dot chain line. The upper limit position Phi is the upper limit position to which the weight 5 can rise. When the weight 5 moves to the upper limit position Phi, the charging port 3a opens and the material to be kneaded can be charged into the chamber 4 from the charging port 3a. The lower limit position Plow is the lower limit position to which the weight 5 can descend. When the weight 5 descends to the lower limit position Plow, the material to be kneaded is filled in the kneading chamber 4a in a sealed state. The weight 5 may be configured to be movable up and down by, for example, a cylinder mechanism, a ball screw, or the like, or may be configured to be movable up and down by other mechanisms.

[0026] [Structure of Leakage Prevention Part] The kneader 1 further includes a leakage prevention part 100 shown in FIGS. 2 and 3. The leakage prevention part 100 functions as a dust seal (sealing part) for preventing the material to be kneaded filled in the kneading chamber 4a of the chamber 4 from leaking out from the end of the kneading rotor 2 to the outside of the kneading chamber 4a.

[0027] The leakage prevention part 100 includes a rotating side seal member 9, a fixed side seal member 10, a plurality of cooling water pipes 16, a plurality of lubricating oil pipes 18, a yoke 20, a pair of yoke pins 21, a yoke bolt 22, and a hydraulic cylinder 23. Further, the kneader 1 has a lubricating oil supply mechanism 50 for supplying lubricating oil to the leakage prevention part 100 (see FIG. 3).

[0028] The fixed side seal member 10 has a ring shape and is attached to the casing 3 so as to surround the rotor shaft portion 2A. The rotating side seal member 9 has a ring shape and is attached to the rotor shaft portion 2A so as to face the fixed side seal member 10. The rotating side seal member 9 is rotatable integrally with the rotor shaft portion 2A while sliding with respect to the fixed side seal member 10. In other words, while the rotating side seal member 9 rotates, the fixed side seal member 10 does not rotate. And the rotating side seal member 9 and the fixed side seal member 10 have ring-shaped opposing surfaces (sliding surfaces, sealing surfaces) facing each other.

[0029] The fixed-side seal member 10 is fitted in a liquid-tight state to the end plate 8 via a seal ring (not shown) on the kneading rotor 2 side so as not to allow the kneaded material or lubricating oil to leak to the outside. Further, as shown in FIG. 2, a cooling water pipe 16 and a lubricating oil pipe 18 are respectively connected to the end plate 8, and when cooling water flows into the cooling water pipe 16, the fixed-side seal member 10 is cooled. Further, when lubricating oil flows into each lubricating oil pipe 18 from the lubricating oil supply mechanism 50 in FIG. 3, lubricating oil is supplied to the sliding portion 14 where the opposing surfaces of the fixed-side seal member 10 and the rotating-side seal member 9 slide against each other.

[0030] Here, the opposing surfaces of the rotating-side seal member 9 and the fixed-side seal member 10 are formed of, for example, a hard facing metal. In addition, examples of materials applicable to these opposing surfaces include various steels, copper alloys, non-oil-impregnated materials such as ceramics and sintered carbon, and oil-impregnated metals such as gunmetal, cast iron, and sintered metal.

[0031] The yoke 20 is a plate material for transmitting the operating force of the hydraulic cylinder 23 to the fixed-side seal member 10. The hydraulic cylinder 23 is attached to one end, and yoke pins 21 are respectively attached to the bifurcated other end. Further, a yoke stud 22 is inserted through the bifurcated portion (substantially the central portion of the yoke 20) of the yoke 20, and the yoke 20 swings about this yoke stud 22 as a fulcrum. The yoke stud 22 is fixed to the end plate 8, and the yoke 20 is supported by the end plate 8 at the yoke stud 22. The tip ends of the two yoke pins 21 are respectively fitted into holes formed in the end face outside the rotor shaft portion 2A of the fixed-side seal member 10.

[0032] The fixed-side seal member 10 is prevented from rotating by yoke pins 21 respectively attached to the bifurcated ends of the yoke 20. Note that the rotation of the fixed-side seal member 10 is more reliably prevented by pressing the yoke pin 21 against the fixed-side seal member 10 via the yoke 20 by the hydraulic cylinder 23. Further, the fixed-side seal member 10 is pressed toward the rotating-side seal member 9 via the yoke pin 21, thereby suppressing leakage of the material to be kneaded from the sliding portion 14 between the fixed-side seal member 10 and the rotating-side seal member 9. Note that the yoke pin 21 corresponds to a pressing portion that presses the fixed-side seal member of the present invention toward the rotating-side seal member.

[0033] The hydraulic cylinder 23 has a cylinder body and a piston rod (not shown), and is a linear actuator in which the piston rod moves linearly by receiving supply and discharge of hydraulic oil therein. An urging mechanism 48 (seal pressurizing mechanism) for applying an urging pressure Ps between the fixed-side seal member 10 and the rotating-side seal member 9 is configured including the yoke 20, the pair of yoke pins 21, the yoke bolt 22, and the hydraulic cylinder 23.

[0034] The hydraulic pressure of the hydraulic oil in the cylinder of the hydraulic cylinder 23 can be adjusted by a hydraulic control valve 24. The hydraulic control valve 24 controls the hydraulic pressure of the hydraulic oil supplied to the hydraulic cylinder 23 using the hydraulic pressure generated by a hydraulic pressure generating device 26 as the source pressure. The hydraulic control valve 24 controls the hydraulic pressure of the hydraulic oil based on a hydraulic pressure signal output from an electronic control device 28.

[0035] The electronic control unit 28 is composed of a computer including a central processing unit (CPU) not shown and storage devices such as a ROM and a RAM not shown, and executes various processes including hydraulic control of the hydraulic oil supplied to the hydraulic cylinder 23, for example. Various signals are input to the electronic control unit 28, such as a signal representing the weight position Po, which is the position of the weight 5 detected by the position sensor 30, a signal representing the pressing pressure Ps (sealing pressure) applied between the fixed-side seal member 10 and the rotating-side seal member 9 detected by the pressing pressure detection sensor 32, and a signal representing the seal interval S between the fixed-side seal member 10 and the rotating-side seal member 9 measured by the eddy current sensor 34. The pressing pressure detection sensor 32 may detect the hydraulic pressure of the hydraulic oil in the hydraulic cylinder 23 and calculate the pressing pressure Ps based on the detected hydraulic pressure. Note that the eddy current sensor 34 corresponds to the seal interval measurement unit that measures the seal interval of the present invention.

[0036] As shown in FIG. 3, the lubricating oil supply mechanism 50 includes a motor 51, a fuel supply mechanism 52, a lubricating oil tank 53, an oil quantity adjustment mechanism 54, and a controller 60.

[0037] The fuel supply mechanism 52 includes a crankshaft 52A and three discharge cylinders 52B (plungers) respectively connected to three crank portions of the crankshaft. The motor 51 rotates in response to a command signal from the controller 60 and rotates the crankshaft 52A in the fuel supply mechanism 52. Each discharge cylinder 52B corresponds to a plunger pump, sucks lubricating oil from the lubricating oil tank 53, and discharges the lubricating oil toward the leakage prevention portion 100 as the crankshaft 52A rotates. At this time, the lubricating oil is supplied through the lubricating oil pipe 18 in FIG. 2, and the lubricating oil flows into the oil injection port 18A formed in the fixed-side seal member 10. Further, the oil injection port 18A penetrates the fixed-side seal member 10 and communicates with the sliding portion 14 between the fixed-side seal member 10 and the rotating-side seal member 9. As a result, the lubricating oil is supplied to the sliding portion 14 via the oil injection port 18A. As a result, a lubricating oil layer W (FIG. 3) is formed on the sliding portion 14. Note that the three crank portions of the crankshaft 52A are arranged at intervals of 120 degrees along the rotation direction, and a phase difference of equal intervals is set between them.

[0038] The fuel quantity adjustment mechanism 54 adjusts the stroke of the piston of the discharge cylinder 52B when the crankshaft 52A of the fuel supply mechanism 52 makes one revolution. As a result, the discharge amount of lubricating oil from each discharge cylinder 52B is adjusted. The fuel quantity adjustment mechanism 54 may be operated by an operator or may adjust the stroke of the piston according to a command signal received from the controller 60.

[0039] As shown in FIG. 3, in the present embodiment, lubricating oil is supplied from three oil injection ports 18A formed in the fixed-side seal member 10 to the sliding portion 14 between the fixed-side seal member 10 and the rotating-side seal member 9. At this time, due to the phase difference of the three crank portions of the crankshaft of the lubricating oil supply mechanism 50, lubricating oil is sequentially supplied to each oil injection port 18A.

[0040] The lubricating oil supply mechanism 50 periodically repeats the supply operation and the stop operation of the lubricating oil so as to intermittently supply the lubricating oil to the sliding portion 14 between the rotating-side seal member 9 and the fixed-side seal member 10. Thereby, while reducing the total supply amount R of the lubricating oil supplied to the sliding portion 14 compared to the case where the lubricating oil is continuously supplied to the sliding portion 14, the seal interval S (oil film thickness) required for the sliding portion 14 can be stably maintained. As a result, since the supply amount R of the lubricating oil decreases, the environmental impact caused by waste oil is reduced, and it is also possible to reduce the running cost of the kneader 1. Further, in the present embodiment, since the lubricating oil is intermittently supplied by the lubricating oil supply mechanism 50, it is possible to prevent instantaneous oil outflow in the sliding portion 14 due to the pulsating supply action, and the lubricating effect can be further enhanced.

[0041] Also, as shown in FIG. 3, two of the three oil inlets 18A are formed near the portion of the fixed-side seal member 10 that is pressed by the yoke pins 21. As a result, lubricating oil is concentrated and supplied to the easily worn portion of the sliding portion 14 between the rotating-side seal member 9 and the fixed-side seal member 10, so that it is possible to further reduce the supply amount R of the lubricating oil. As an example of the definition of the vicinity of the portion pressed by the yoke pin 21, a case can be exemplified where the circumferential distance between the oil inlet 18A and the yoke pin 21 is smaller than the circumferential distance between the oil inlet 18A and the midpoint between the two yoke pins 21 in the circumferential direction. Further, the oil inlet 18A is arranged such that the circumferential distance between the oil inlet 18A and the yoke pin 21 is 30% or less, preferably 20% or less, and more preferably 10% or less of the circumferential distance between the midpoint and the yoke pin 21.

[0042] As described above, the leakage prevention portion 100 supplies lubricating oil to the sliding portion 14 between the rotating-side seal member 9 and the fixed-side seal member 10 via the lubricating oil supply mechanism 50, and presses the fixed-side seal member 10 toward the rotating-side seal member 9 by the pressing mechanism 48. Thereby, by setting the pressing pressure Ps (seal pressure) between the rotating-side seal member 9 and the fixed-side seal member 10 to a value that suppresses the leakage of the kneaded material, the leakage of the kneaded material from the leakage prevention portion 100 can be suppressed.

[0043] Next, the kneading process of the kneaded material will be described. FIG. 4 is a time chart for explaining the position of the weight position Po, which is the position of the weight 5 in the kneading process of the kneaded material. In FIG. 4, the horizontal axis represents time t [sec], and the vertical axis represents the weight position Po [mm], which is the vertical position of the weight 5.

[0044] Period A shown in FIG. 4 is the period during which the material to be kneaded is charged into chamber 4. In period A, with weight 5 positioned at the upper limit position Phi, the material to be kneaded can be charged into chamber 4. At this time, additives such as fillers may be appropriately added. Period B is the period from the time when weight 5 starts to descend after the material to be kneaded is charged into chamber 4 until weight 5 reaches the lower limit position Plow, that is, the material intake period for taking the material to be kneaded into kneading chamber 4a. Period C is the period of raising and lowering weight 5 temporarily after the material is taken in. Period D is the material kneading period for kneading the material to be kneaded in kneading chamber 4a of chamber 4. Period E is the material discharge period for removing the material to be kneaded in chamber 4 by removing drop door 6.

[0045] Immediately after the material to be kneaded is charged into chamber 4 in period A, weight 5 is positioned at the upper limit position Phi. At this time, the filling amount of the material to be kneaded is larger than the capacity of kneading chamber 4a of chamber 4, and the material to be kneaded overflows to the vicinity of inlet 3a. In period B, weight 5 descends from the upper limit position Phi, and weight 5 pushes the material to be kneaded into kneading chamber 4a. After weight 5 temporarily rises and descends to the lower limit position Plow in period C, the material to be kneaded is kneaded in period D. As the material to be kneaded is kneaded between period B and period D, the volume of the material to be kneaded gradually decreases, and the filling rate of the material to be kneaded in kneading chamber 4a becomes lower than 100%. In period E, with weight 5 positioned at the lower limit position Plow, drop door 6 is removed and the material to be kneaded is taken out from discharge port 3b.

[0046] Here, during the material intake period (corresponding to period B in FIG. 4) in which the material to be kneaded is taken into the kneading chamber 4a of the chamber 4 in the above-described series of kneading steps, it was confirmed that the material to be kneaded is likely to leak from the leakage prevention portion 100. During the material intake period, the material to be kneaded is pushed into the kneading chamber 4a by the weight 5. Immediately after the material to be kneaded is introduced into the chamber 4, the volume of the material to be kneaded becomes larger than the volume of the kneading chamber 4a, and the filling rate of the material to be kneaded with respect to the kneading chamber 4a exceeds 100%. Therefore, during the transient period when the weight 5 descends during the material intake period, the weight 5 pushes the material to be kneaded. At this time, when the material to be kneaded is pressed by the weight 5, a force directed outward is generated in the material to be kneaded. It is considered that when this force becomes larger than the pressing pressure Ps applied between the fixed-side seal member 10 and the rotating-side seal member 9 of the leakage prevention portion 100, the material to be kneaded is likely to leak from the leakage prevention portion 100.

[0047] In order to suppress the leakage of the material to be kneaded during the material intake period, it is necessary to increase the pressing pressure Ps applied to the sliding portion 14 between the rotating-side seal member 9 and the fixed-side seal member 10 of the leakage prevention portion 100. On the other hand, when the pressing pressure Ps is increased, the sliding portion 14 is likely to wear. In contrast, the electronic control device 28 increases the pressing pressure Ps applied to the sliding portion 14 during the material intake period compared to other periods. Further, the electronic control device 28 increases the supply amount R of the lubricating oil supplied from the lubricating oil supply mechanism 50 to the leakage prevention portion 100 compared to the other periods. Note that the other periods correspond to period A, periods C to E in FIG. 4.

[0048] The electronic control device 28 functionally includes a pressing pressure control unit 80 that controls the pressing pressure Ps applied to the sliding portion 14 between the fixed-side seal member 10 and the rotating-side seal member 9 of the leakage prevention portion 100, and a lubricating oil amount control unit 82 that controls the supply amount R of the lubricating oil supplied from the lubricating oil supply mechanism 50 to the leakage prevention portion 100.

[0049] The pressing pressure control unit 80 determines whether it is the material intake period. The material intake period is set as the period from the time when the material to be kneaded is put into the chamber 4 to the time when the weight 5 reaches the lower limit position Plow. The pressing pressure control unit 80 determines whether it is the material intake period based on, for example, the weight position Po of the weight 5 detected by the position sensor 30. Note that the lubricating oil amount control unit 82 may determine whether it is the material intake period.

[0050] The start time of the above material intake period may be, for example, the time when the weight 5 starts to descend, or the time when the weight 5 descends to a predetermined position immediately before contacting the material to be kneaded. The above predetermined position can be obtained in advance based on experiments or the like. Or, it may be the time when the weight 5 actually contacts the material to be kneaded. In this case, for example, by detecting the load applied to the weight 5, it is possible to determine whether the weight 5 has contacted the material to be kneaded.

[0051] Also, the end time of the material intake period may be the time when a predetermined time set in advance has elapsed from the start time of the material intake period, or the time when the weight 5 starts to rise. The above predetermined time is the time required for the weight 5 to descend to the lower limit position Plow, and can be obtained in advance based on experiments or the like. Thus, the material intake period only needs to include at least a part of the period during which the weight 5 pushes the material to be kneaded among the period from when the material to be kneaded is put into the chamber 4 to the time when the weight 5 reaches the lower limit position Plow.

[0052] When it is the material intake period, the pressing pressure control unit 80 increases the pressing pressure Ps applied to the sliding part 14 of the leakage prevention part 100 compared to other periods outside the material intake period. Specifically, the pressing pressure control unit 80 increases the pressing pressure Ps applied to the sliding part 14 by increasing the hydraulic pressure of the hydraulic oil supplied to the hydraulic cylinder 23. The pressing pressure Ps during the material intake period is obtained experimentally or design-wise in advance and is set to a value that can suppress the leakage of the material to be kneaded from the leakage prevention part 100. As a result, the leakage of the material to be kneaded from the leakage prevention part 100 during the material intake period is suppressed.

[0053] Further, when the pressing pressure Ps applied to the sliding portion 14 of the leakage prevention portion 100 increases, the sliding portion 14 is likely to wear. In contrast, the lubricating oil amount control unit 82 increases the supply amount R of the lubricating oil supplied from the lubricating oil supply mechanism 50 to the leakage prevention portion 100 during the material intake period as compared with other periods other than the material intake period. The lubricating oil amount control unit 82 increases the supply amount R of the lubricating oil supplied to the leakage prevention portion 100 by increasing the rotation speed of the motor 51 or increasing the stroke of the discharge cylinder 52B of the oil amount adjustment mechanism 54 during the material intake period as compared with other periods. As a result, although the sliding portion 14 is likely to wear during the material intake period, the supply amount R of the lubricating oil supplied to the leakage prevention portion 100 increases, so that the wear of the sliding portion 14 is reduced.

[0054] In addition, in other periods other than the material intake period, the pressing pressure Ps applied to the leakage prevention portion 100 is smaller than that in the material intake period. Even when the pressing pressure Ps becomes smaller, in other periods other than the material intake period, since the kneaded material is less likely to leak from the leakage prevention portion 100, the leakage of the kneaded material is suppressed as in the material intake period. Further, when the pressing pressure Ps becomes smaller, the load applied to the sliding portion 14 becomes smaller, so that the sliding portion 14 is less likely to wear. Therefore, the supply amount R of the lubricating oil supplied to the leakage prevention portion 100 in other periods can be reduced compared to the material intake period, and as a result, the total supply amount of the lubricating oil in the kneading process can be reduced.

[0055] FIG. 5 is a time chart for explaining changes in the supply amount R [cc / s] of the lubricating oil and the pressing pressure Ps [MPa] in the kneading process. In FIG. 5, the horizontal axis represents the time t [sec], and the vertical axis represents the weight position Po [mm] of the weight 5, the supply amount R [cc / s] of the lubricating oil, and the pressing pressure Ps [N], respectively.

[0056] The weight position Po indicated by the solid line in FIG. 5 is the same as that in FIG. 4 described above, and thus its description is omitted. The pressing pressure Ps indicated by the dashed line increases during the material intake period (period B) compared to other periods. Specifically, while the pressing pressure Ps in other periods outside the material intake period is the second pressure Ps2, during the material intake period, the pressing pressure Ps is the first pressure Ps1, which is higher than the second pressure Ps2. Note that the second pressure Ps2 of the pressing pressure Ps may be, for example, about 1 / 3 of the first pressure Ps1. Similarly, the supply rate R [cc / s] of the lubricating oil indicated by the dash-dotted line increases during the material intake period compared to other periods. Specifically, while the supply rate R in other periods is the second oil amount R2, during the material intake period, it is the first oil amount R1, which is larger than the second oil amount R2. Note that the second oil amount R2 of the supply rate R may be, for example, about 1 / 3 of the first oil amount R1.

[0057] Also, when a wear test was conducted with the pressing pressure Ps and the supply rate R of the lubricating oil in the kneading process controlled as shown in FIG. 5, the wear amount of the sliding portion 14 was suppressed to 1 μm or less even after 8 hours. Thus, even if the supply rate R of the lubricating oil is decreased while the pressing pressure Ps is decreased in other periods outside the material intake period, the wear of the sliding portion 14 can be suppressed.

[0058] By the way, in the wear test, when the material to be kneaded leaked from the leakage prevention portion 100 during the material intake period, the seal interval S between the fixed-side seal member 10 and the rotating-side seal member 9 increased. FIG. 6 is a time chart for explaining the behavior of the seal interval S when leakage of the material to be kneaded occurred and when it did not occur during the material intake period. In FIG. 6, the dashed line indicates the seal interval Sa when leakage of the material to be kneaded did not occur, and the solid line indicates the seal interval Sb when leakage of the material to be kneaded occurred.

[0059] When there is no leakage of the material to be kneaded, as shown by the dashed line, the seal interval Sa hardly changes even during the material intake period (period B), and the seal interval Sa substantially maintains its initial state. On the other hand, when the material to be kneaded leaks, as shown by the solid line, the seal interval Sb fluctuates during the material intake period and temporarily exceeds 0.4 mm. That is, when the material to be kneaded leaks, the seal interval S increases by 0.3 mm or more compared to the initial value (0.0 mm) during the material intake period B. Also, after passing period B, it shows that the seal interval S converges. From this, by measuring the seal interval S, it is possible to detect a sign of leakage of the material to be kneaded.

[0060] Therefore, the electronic control device 28 functionally includes a leakage prediction detection unit 84 that detects a sign of leakage of the material to be kneaded based on the seal interval S. The leakage prediction detection unit 84 determines that there is a sign of leakage of the material to be kneaded when the seal interval S, which is measured at any time by the eddy current sensor 34 during the material intake period, becomes equal to or greater than a preset predetermined value Sth. The predetermined value Sth is obtained in advance experimentally or analytically and is set to a value at which it can be determined that there is a risk of leakage of the material to be kneaded. When the leakage prediction detection unit 84 detects a sign of leakage of the material to be kneaded, that is, when the seal interval S measured by the eddy current sensor 34 becomes equal to or greater than the predetermined value Sth, it causes the alarm 36 to output a warning sound. Thereby, the operator can know that there is a sign of leakage of the material to be kneaded. Note that the alarm 36 corresponds to the material leakage warning unit of the present invention.

[0061] Further, when the pressing pressure control unit 80 detects a sign of leakage of the material to be kneaded, it further increases the pressing pressure Ps applied to the sliding portion 14. The pressing pressure Ps at this time becomes a value higher than the first pressure Ps1 set during the material intake period. For example, when the pressing pressure control unit 80 detects a sign of leakage of the material to be kneaded, it corrects the pressing pressure Ps to the increasing side by executing feedback control with the difference (=|S - Sth|) between the seal interval S measured at any time and the predetermined value Sth as a deviation. Thereby, the pressing pressure Ps is appropriately adjusted according to the seal interval S, and leakage of the material to be kneaded can be surely suppressed.

[0062] FIG. 7 is a flowchart for explaining the control operation of the electronic control device 28 in the kneading process. The flowchart of FIG. 7 explains the control for adjusting the pressing pressure Ps applied to the sliding portion 14 and the supply amount R of the lubricating oil during the kneading process of the material to be kneaded. In this flowchart, it is repeatedly executed during the kneading process.

[0063] When the kneading of the material to be kneaded starts, the electronic control device 28 determines whether it is the material intake period (S10). If it is not the material intake period (No in S10), the electronic control device 28 controls the pressing pressure Ps to the second pressure Ps2 set in a period other than the material intake period (S60). Further, the electronic control device 28 controls the supply amount R of the lubricating oil to the second oil amount R2 preset in a period other than the material intake period (S60). On the other hand, if the electronic control device 28 determines that it is the material intake period (Yes in S10), it increases the pressing pressure Ps more than in other periods (S20). Specifically, the electronic control device 28 controls the pressing pressure Ps to the first pressure Ps1, which is higher than the second pressure Ps2. Further, the electronic control device 28 increases the supply amount R of the lubricating oil more than in other periods (S20). Specifically, the electronic control device 28 controls the supply amount R to the first oil amount R1, which is larger than the second oil amount R2. Next, the electronic control device 28 determines whether the seal interval S has become equal to or greater than a preset value Sth (S30). If the seal interval S is less than the preset value Sth (No in S30), the electronic control device 28 maintains the pressing pressure Ps at the first pressure Ps1 and maintains the supply amount R at the first oil amount R1. On the other hand, if the seal interval S is equal to or greater than the preset value Sth (Yes in S30), the electronic control device 28 executes control to further increase the pressing pressure Ps according to the seal interval S (S40). Along with this, the supply amount of the lubricating oil may be further increased. Also, a warning sound can be emitted from the alarm 36. Next, the electronic control device 28 determines whether it has entered a period other than the material intake period (S50). If it is currently the material intake period (No in S50), the electronic control device 28 returns to S30 and continues to execute the control during the material intake period. On the other hand, if it has entered a period other than the material intake period (Yes in S50), the electronic control device 28 controls the pressing pressure Ps to the second pressure Ps2 and controls the supply amount R of the lubricating oil to the second oil amount R2 (S60).

[0064] [Effect] As described above, in the kneading process, in the material intake period when the material to be kneaded is more likely to leak compared to other periods, by increasing the pressing pressure Ps applied to the sliding portion 14 between the fixed-side seal member 10 and the rotating-side seal member 9, leakage of the material to be kneaded is suppressed. Also, in the material intake period, by increasing the supply amount R of the lubricating oil together, even if the pressing pressure Ps increases during the material intake period, wear of the leakage prevention portion 100 is reduced. On the other hand, in other periods other than the material intake period, since the material to be kneaded is less likely to leak even if the pressing pressure Ps is made smaller compared to the material intake period, the pressing pressure Ps is controlled to be lower than in the material intake period. Correspondingly, by also reducing the supply amount R of the lubricating oil compared to the material intake period, the total supply amount of the lubricating oil in the kneading process can be reduced.

[0065] Also, when the seal interval S between the fixed-side seal member 10 and the rotating-side seal member 9 becomes equal to or greater than a predetermined value Sth, a warning is issued from the alarm 36, so that a sign of leakage of the material to be kneaded can be detected. Further, when the seal interval S becomes equal to or greater than the predetermined value Sth, the pressing pressure Ps is further increased. Therefore, when a sign of leakage of the material to be kneaded is detected, leakage of the material to be kneaded can be suppressed by further increasing the pressing pressure Ps. At this time, if the supply amount of the lubricating oil is further increased, leakage of the material to be kneaded can be further suppressed.

[0066] [Modification Example] In the above embodiment, the pressing mechanism 48 swings the yoke 20 by the hydraulic cylinder 23, but it is not necessarily limited to the hydraulic cylinder 23. For example, instead of the hydraulic cylinder 23, a pneumatic cylinder may be used for the pressing mechanism 48. Also, a device other than a cylinder may be used as a mechanism for swinging the yoke 20, such as swinging the yoke 20 via a ball screw or swinging the yoke 20 by a spring.

[0067] In the above-described embodiment, the pressing mechanism 48 presses the fixed-side seal member 10 toward the rotating-side seal member 9 via the yoke 20. However, the present invention does not necessarily require the yoke 20. Specifically, the pressing mechanism 48 may have a structure that directly presses the fixed-side seal member 10 by a hydraulic cylinder (or a pneumatic cylinder), a ball screw, a spring, or the like.

[0068] In the above-described embodiment, the yoke 20 presses the fixed-side seal member 10 at two points via the yoke pins 21. However, the number of portions pressing the fixed-side seal member 10 is not limited to two points. For example, the yoke 20 may be configured to press the fixed-side seal member 10 at three points.

[0069] In the above-described embodiment, three oil injection ports 18A are formed in the fixed-side seal member 10. However, the number of the oil injection ports 18A is not limited thereto. For example, two oil injection ports 18A may be formed in the vicinity of the yoke pins 21 of the yoke 20, or four or more oil injection ports 18A may be formed.

[0070] In the above-described embodiment, the pressing pressure Ps is feedback-controlled based on the deviation between the seal interval S and the predetermined value Sth during the material intake period. However, the present invention is not necessarily limited thereto. For example, a relationship map between the pressing pressure Ps and the seal interval S may be stored in advance, and the pressing pressure Ps may be determined with reference to the relationship map during the material intake period.

[0071] Furthermore, in the above-described embodiment, the weight 5 is temporarily raised to the upper limit position Phi in the period C. However, it is not necessarily required to raise it to the upper limit position Phi, and steps other than the periods A to E may be added. Also, in the above-described embodiment, as shown in FIG. 5, the pressing pressure Ps and the lubricating oil supply amount R in the periods D and E are set to the same value, but they may be changed to values suitable for each period.

Description of Reference Numerals

[0072] 1: Kneader (sealed kneader) 2: Kneading rotor 2A: Rotor shaft portion 2B: Kneading blade portion 3: Casing 4: Chamber 5: Weight 9: Rotating side seal member 10: Fixed side seal member 18A: Oil filling port 21: Yoke pin (pressing portion) 34: Eddy current sensor (seal interval measurement portion) 36: Alarm (material leakage warning portion) 48: Pressing mechanism (seal pressurizing mechanism) 50: Lubricating oil supply mechanism 100: Leakage prevention portion

Claims

1. A casing having a chamber therein for accommodating an object to be kneaded; A kneading rotor including a rotor shaft portion extending outside the chamber and a kneading blade portion disposed inside the chamber, and kneading the material to be kneaded in the chamber by rotating; A weight that is provided in the casing so as to be movable up and down and that pushes the material to be mixed that is introduced into the chamber; a leakage prevention unit that prevents the material to be kneaded in the chamber from leaking to the outside of the chamber; a lubricant supply mechanism for supplying lubricant to the leakage prevention unit; the leakage prevention unit includes a fixed-side seal member attached to the casing so as to surround the rotor shaft portion, and a rotating-side seal member attached to the rotor shaft portion so as to face the fixed-side seal member and rotatable while sliding relative to the fixed-side seal member, The lubricating oil supply mechanism increases the amount of lubricating oil supplied to the leakage prevention section during a material intake period in which the material to be kneaded is taken into the chamber.

2. 2. The internal mixer according to claim 1, further comprising a seal pressurizing mechanism that increases a pressure applied between the fixed side seal member and the rotating side seal member during the material intake period.

3. 3. The internal mixer according to claim 1, wherein the material intake period includes at least a part of a period during which the weight pushes the material to be mixed after the material to be mixed is introduced into the chamber until the weight reaches a predetermined lower limit position.

4. 3. The internal mixer according to claim 1, further comprising: a seal gap measuring unit that measures a seal gap between the fixed side seal member and the rotating side seal member; and a material leakage warning unit that issues a warning when the seal gap measured by the seal gap measuring unit becomes equal to or greater than a predetermined value.

5. a seal gap measuring unit for measuring a seal gap between the stationary seal member and the rotating seal member, 3. The internal mixer according to claim 2, wherein when the seal gap measured by the seal gap measuring unit reaches or exceeds a predetermined value, the seal pressurizing mechanism further increases the pressure applied between the fixed side seal member and the rotating side seal member.

6. the seal pressure mechanism has a pressing portion that presses the stationary seal member against the rotating seal member, the lubricating oil supply mechanism has an oil inlet that penetrates the stationary seal member and supplies lubricating oil between the stationary seal member and the rotating seal member, 3. The internal mixer according to claim 2, wherein the oil inlet is formed in the vicinity of a portion of the fixed seal member that is pressed by the pressing portion.

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