Classifier and method for designing the classifier

Abstract

To provide a classifier of low-rotation which exhibits high classification performance and can design a blade rotor mechanism part which does not cause liquid leakage even if the classifier has a non-contact seal, and a method for designing the same.SOLUTION: This classifier comprises: a housing; a classification rotor that is provided in the housing to classify particles into fine particles and coarse particles; a rotary shaft of the classification rotor that is provided to penetrate the housing; fine particle discharge means; a coarse particle exit; and sealing means for sealing the housing and the rotary shaft. The classification rotor is provided with a classification blade and a plurality of rectification blades arranged closer to the inside part than the classification blade, and formed such that the ratio of the outer diameters db of the blades to the outer diameter dr of the classification rotor (db / dr) can be a blade / classification rotor ratio (db / dr) corresponding to a design maximum classification rotor peripheral velocity on the basis of a correlation between an experimentally acquired blade / classification rotor ratio (db / dr) and a classification rotor peripheral velocity at the time of a liquid leakage stop from the sealing means.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a classifier, in particular, a wet classifier having a non-contact seal portion that does not use a mechanical seal, and a design method for this classifier.

Background Art

[0002] (1. General description of a classifier)

[0003] As a classifier for classifying fine particles with high precision, there is a device that rotates a classification rotor in which classification blades are spaced apart from each other in the circumferential direction (with a desired interval in the circumferential direction), arranged radially from the rotation center, or arranged such that the center line in the width direction facing the longitudinal direction of the blade does not face the rotation center at high speed to classify the fine particles.

[0004] In this classification, while a fluid such as gas or liquid flows into the classification chamber formed between adjacent classification blades of the classification rotor from the outer peripheral portion and moves toward the inner peripheral side, the particles in the fluid are subjected to the centrifugal force F due to the high-speed rotation of the classification rotor and the resistance R of the fluid flowing in the inner peripheral direction opposite to the acting direction of this centrifugal force. Coarse particles having a diameter larger than the classification particle diameter at which the two balance (F = R) are discharged outside the classification rotor, and fine particles having a smaller diameter flow into the classification rotor.

[0005] In addition, in order to rotatably seal (hermetically seal) the housing of the classifier and the rotating shaft provided through the housing, a non-contact seal portion having a blade rotor mechanism portion (sealing means) without a sliding portion is provided without using a mechanical seal portion that slidably supports the rotating shaft. There is a classifier.

[0006] (2. Specific description of a conventional classifier having a non-contact seal portion)

[0007] Figures 17 to 21 show the conventional wet seal-less classifier 1. The classifier 1 includes, for example, a cylindrical housing 2 with a diameter of 50 mm to 300 mm, a classification rotor 3 provided in the housing 2, a rotary shaft 4 of the classification rotor 3 vertically provided through a through hole 2b formed in the ceiling plate 2a of the housing 2, a rotating means 5 including a motor or the like for rotationally driving the rotary shaft 4, an axially extending through hole (fine particle discharging means) 6 formed in the rotary shaft 4 for discharging the fine particles classified by the classification rotor 3 and flowing into the classification rotor 3 to the outside of the housing 2, a recovery chamber 7 communicating with the other end of the through hole 6 formed in the rotary shaft 4 for guiding the classified fine particles to a recovery tank (not shown), a discharge port 8 for discharging the coarse particles not classified by the classification rotor 3 to the outside of the housing 2, and a supply port 11 for supplying a raw material slurry containing particles to be classified, for example, with a size of 0.1 μm to 100 μm, from a raw material tank 9 storing the raw material slurry into the housing 2 by a supply pump 10.

[0008] Reference numeral 12 indicates a support portion for rotatably supporting the rotary shaft 4.

[0009] In addition, a blade rotor mechanism portion is provided to hermetically seal (liquid-tightly seal) the through hole 2b in the ceiling plate 2a and the rotary shaft 4 in a non-contact manner.

[0010] The blade rotor mechanism portion includes, for example, a disk plate 13 formed larger than the through hole 2b and fixed orthogonally to the rotary shaft 4 passing through the through hole 2b formed in the ceiling plate 2a of the housing 2 in such a manner that its upper surface faces and approaches the inner surface of the ceiling plate 2a of the housing 2, and blades 14 fixed to the upper surface of the disk plate 13 and radially arranged from the rotation center at a desired interval in the circumferential direction (with a desired interval in the circumferential direction) and spaced apart from each other in the circumferential direction and extending in the radial direction and formed of a plurality of bar bodies with a rectangular cross-section and approaching the inner surface of the ceiling surface 2a.

[0011] The inner surface of the ceiling plate 2a is formed in a flat surface shape orthogonal to the rotary shaft 4 passing through and is adapted to face the upper surface of the disk plate 13.

[0012] Also, as shown in FIG. 19, for example, each of the blades 14 is formed in the same shape with a desired length and provided on the outer peripheral side of the upper surface of the disk 13. Further, the outer ends of the blades 14 are provided to coincide with the outer ends of the disk 13 or to be located slightly inside.

[0013] And a blade rotor is configured by the plurality of blades 14 arranged in a circular shape.

[0014] Reference numeral 15 denotes a slurry discharge chamber for collecting the leaked slurry when the slurry in the housing 2 leaks outside the housing 2 through the blade rotor mechanism portion and the through hole 2b.

[0015] Also, as shown in FIGS. 20 and 21, for example, the classification rotor 3 includes two identical disk-shaped plates 16a and 16b spaced apart vertically and coaxially arranged, and a discharge port 3a provided at the center of the upper plate 16a and communicating with the through hole 6, forming a frame body 16. A plurality of classification vanes 17 are provided at equal intervals in the circumferential direction between the outer peripheral side portions of the opposing surfaces of the two plates 16a and 16b, radially from the rotation center, or with the center line in the width direction not facing the rotation center when facing the longitudinal direction of the vane. A plurality of straightening vanes 22 are arranged radially from the rotation center or with the center line in the width direction not facing the rotation center inside the frame body 16 and inside the classification vanes 17 at a desired interval in the circumferential direction. Classification chambers 18 are formed between the adjacent classification vanes 17.

[0016] Note that the straightening vanes 22 are mainly for stabilizing the flow inside the classification rotor, but may not be provided.

[0017] In the classifier 1, the raw material slurry from the raw material tank 9 is supplied into the housing 2 through the supply port 11 by the supply pump 10. The raw material slurry is classified into a coarse particle slurry and a fine particle slurry by the high-speed rotating classification rotor 3 provided in the classifier 1. The coarse particle slurry is discharged out of the housing 2 from the discharge port 8 of the housing 2 of the classifier 1. The fine particle slurry flowing into the classification rotor 3 from the opening on the outer peripheral portion of the classification rotor 3 passes through the through-hole 6 of the rotating shaft 4 fixed to the classification rotor 3 from the discharge port 3a communicating with one end of the through-hole 6 of the rotating shaft 4 formed in the classification rotor 3, and flows into the recovery chamber 7 from the other end of the through-hole 6, and is recovered into the recovery tank.

[0018] Further, when the disk 13 rotates at high speed, the inside of the housing 2 can be made into a sealed structure. Since the inner surface of the ceiling plate 2a and the blade 14 are separated from each other, troubles such as consumption, wear, and sticking of a mechanical seal portion can be eliminated.

[0019] For example, Patent Document 1 is a classifier having a non-contact seal portion.

Prior Art Documents

Patent Documents

[0020]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0021] In the classification operation, a hydraulic pressure due to centrifugal force acting toward the outer periphery is generated on the outer peripheral portion of the classification rotor. In order to allow the stock solution to enter the classification rotor, it is necessary to seal the inside of the classifier in order to ensure a hydraulic pressure that overcomes that pressure.

[0022] In addition, when the liquid inside the machine reaches the outer periphery of the blade rotor that rotates at high speed, the operation of the blade rotor mechanism is such that a centrifugal force acting toward the outer periphery creates a state where the liquid does not penetrate into the blade rotor, and an operation to prevent liquid leakage to the outside of the machine is performed.

[0023] That is, the blade rotor mechanism functions as a resistor and exhibits a sealing effect.

[0024] Regarding the generated pressure due to the structural difference between the blade rotor mechanism and the classification rotor, as described above, the blade rotor mechanism has a structure with a gap between the blade rotor and the inner wall surface of the housing 2. Compared with the classification rotor in which blades are sandwiched between disks, liquid leakage is likely to occur, and the generated (resistance) pressure / theoretical pressure becomes lower.

[0025] Therefore, for the same diameter, the pressure of the classification rotor is higher than that of the blade rotor mechanism. As a result, the liquid inside the machine leaks from the blade rotor mechanism and the sealing effect is not achieved. It was predicted that in order to prevent this and provide a sealing effect without liquid leakage, it is necessary to set the blade rotor diameter larger than the classification rotor diameter.

[0026] However, it was not clear how much larger it should be.

[0027] Therefore, as a result of various experimental studies, the inventor of the present application has determined the relationship between the blade rotor diameter and the classification rotor diameter at which no liquid leakage occurs from the blade rotor mechanism, and has established the optimization of the blade rotor mechanism by obtaining the operating conditions.

Means for Solving the Problems

[0028] To achieve the above object, the classifier of the present invention comprises a housing to which a raw material containing particles to be classified is supplied, a classification rotor provided in the housing for classifying into fine particles and coarse particles, a rotating shaft of the classification rotor provided through the housing, rotating means for rotationally driving the rotating shaft, fine particle discharging means for discharging the classified fine particles flowing into the classification rotor to the outside of the housing, a discharge port for discharging the coarse particles not classified by the classification rotor to the outside of the housing, supply means for supplying the raw material to the housing, and sealing means for sealing the housing and the rotating shaft. The classification rotor comprises a rotatable frame body having an opening at an outer peripheral portion and a discharge port for discharging the fluid flowing into the inside from the opening to the outside, and a plurality of classification blades arranged at a desired interval in the circumferential direction at an outer peripheral side portion within the frame body. The sealing means comprises a plate body fixed orthogonally to the rotating shaft and a plurality of blades fixed to the surface of the plate body and arranged at a desired interval in the circumferential direction and close to the inner surface of the housing. The outer diameter d of the blade rotor formed by arranging the plurality of blades in a circular shape b and the outer diameter d of the classification rotor r The ratio (d b / d r ) is formed to be the blade / classification rotor ratio (d b / d r ) obtained by experiments and corresponding to the maximum designed classification rotor peripheral speed at the time of stopping liquid leakage from the sealing means, so as to be the blade / classification rotor ratio (d b / d r ).

[0029] Further, when the maximum designed classification rotor peripheral speed is 30 m / s, the blade / classification rotor ratio (d b / d r ) is 1.204.

[0030] In addition, the classification machine design method of the present invention comprises a housing to which a raw material containing particles to be classified is supplied, a classification rotor provided in the housing for classifying into fine particles and coarse particles, a rotating shaft of the classification rotor provided through the housing, a rotating means for rotationally driving the rotating shaft, fine particle discharge means for discharging the classified fine particles flowing into the classification rotor to the outside of the housing, a discharge port for discharging the coarse particles not classified by the classification rotor to the outside of the housing, supply means for supplying the raw material to the housing, and sealing means for sealing the housing and the rotating shaft. The classification rotor comprises a rotatable frame body having an opening at the outer peripheral portion and a discharge port for discharging the fluid flowing into the interior from the opening to the outside, and a plurality of classification blades arranged at a desired interval in the circumferential direction at the outer peripheral side portion within the frame body. The sealing means comprises a plate body fixed orthogonally to the rotating shaft and a plurality of blades arranged at a desired interval in the circumferential direction and fixed to the surface of the plate body and brought close to the inner surface of the housing. The blade / classification rotor ratio (d b / d r ) and the correlation with the circumferential speed of the classification rotor at the time of stopping liquid leakage from the sealing means are obtained, and from the correlation, the blade / classification rotor ratio (d b / d r ) corresponding to the maximum circumferential speed of the classification rotor in design is obtained, and the classification machine is designed so as to have the obtained blade / classification rotor ratio (d b / d r ).

[0031] In addition, a plurality of straightening blades arranged at a desired interval in the circumferential direction are provided in the inner side portion of the frame body inside the classification blades.

Advantages of the Invention

[0032] According to the present invention, even in a classification machine having a non-contact seal portion, it is possible to design a blade rotor mechanism portion without liquid leakage, and it is possible to provide a classification machine having a large classification performance (processing capacity) and low rotation.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

[0034] Examples of modes for carrying out the present invention are shown below.

[0035] The same parts as those explained in the background art are given the same reference numerals and their explanations are omitted. [Example]

[0036] 3. DESCRIPTION OF THE INVENTION

[0037] The inventors have investigated the diameter of the blade rotor (d b ) and the diameter of the classification rotor (d r ) and the rotor diameter (d b ) and the diameter of the classifying rotor (d r ) and the blade / classifying rotor ratio (d b / d r ) is constant, there is no leakage even if the blade rotor diameter and the classifying rotor diameter are changed at the same peripheral speed of the classifying rotor.

[0038] Also, the blade / classifying rotor ratio (d b / d r ) decreases, it was found that the peripheral speed of the classification rotor needs to be increased to prevent liquid leakage.

[0039] Also, when the blade / classifying rotor ratio (d b / d r ) is kept constant, it was found that the higher the circumferential speed of the classifying rotor, the less likely liquid leakage occurs.

[0040] Also, the classification performance (processing capacity) is proportional to the square of the circumferential speed of the classifying rotor as shown in Equation 6 described later when the classification particle size is constant. Thus, it was found that the higher the circumferential speed of the classifying rotor, the higher the processing capacity.

[0041] Therefore, in the classifier to be developed (designed), the correlation between the blade / classifying rotor ratio (d b / d r ) and the circumferential speed of the classifying rotor at which liquid leakage stops was derived through experiments and the like. Based on this correlation, the optimal blade rotor diameter (d b ) and the classifier rotor diameter (d r ) at the maximum circumferential speed of the classifying rotor in the design of the classifier to be developed were derived, and the ratio (d b / d r ) was obtained. It was found that an optimal classifier can be developed by using this value.

[0042] The following is a specific description.

[0043] FIG. 1 shows a classifier 19 for setting optimal conditions having a blade rotor mechanism part used for obtaining the optimal conditions of the classifier to be developed. The classifier 19 has the same basic configuration as the conventional classifier 1, but is provided with a pressure gauge 20 for measuring the pressure in the housing (inside the machine) 2.

[0044] Note that the classifier 19 in FIG. 1 is an example in which a disk 13 of the blade rotor mechanism part is fixed above the classifying rotor 3. However, for example, as shown in FIG. 2, even if the blade rotor mechanism part is provided at a distance above the classifying rotor 3, it has the same effect as the classifier 19.

[0045] Further, as shown in FIGS. 3 and 4, even in a blade rotor mechanism portion in which a plurality of grooves 21 extending in the radial direction are formed on the upper surface of the disk 13 and the remaining convex portions between the grooves 21 are used as blades 14, it has the same effect as the classifier 19.

[0046] Also, although the classifier 19 of the present embodiment shows an example in which the stock solution is introduced from below, even a classifier in which the stock solution is introduced from above has the same effect as the classifier 19.

[0047] Then, in order to find the optimal conditions of the classifier to be developed, using the classifier 19, with the blade rotor diameter (d b ) fixed at 0.054 m, the classifier rotor diameter (d r ) being 0.038 m in Experiment 1, 0.043 m in Experiment 2, 0.044 m in Experiment 3, and 0.45 m in Experiment 4, continuously supply a small amount of water into the classifier filled with water, allow water to leak out of the classifier from the blade rotor mechanism portion or the classifier rotor side, and while increasing the rotational speed of the classifier rotor, measure the internal pressure of the machine with the pressure gauge 20, and visually determine the peripheral speed of the classifier rotor when the water leakage from the blade rotor mechanism portion to the outside stops. Note that when increasing the rotational speed of the classifier rotor, initially, water leakage occurs only from the blade rotor mechanism portion, but from a desired rotational speed, the water leakage from the blade rotor mechanism portion stops and water is discharged to the outside from the classifier rotor side.

[0048] That is, Experiments 1 to 4 show experiments when the blade / classifier rotor ratio (d b / d r ) is changed.

[0049] Also, the blade / classifier rotor ratio (d b / d rIn Experiment 5, the blade rotor diameter was set to 0.086 m and the classification rotor diameter was set to 0.0685 m, and in Experiment 6, the blade rotor diameter was set to 0.100 m and the classification rotor diameter was set to 0.0796 m, so that the ratio (1.256) was the same as in . In the same manner as described above, water was supplied, and while increasing the rotational speed of the classification rotor, the in-machine pressure was measured by the pressure gauge 20, and the peripheral speed of the classification rotor was determined visually when water leakage from the blade rotor mechanism section to the outside stopped.

[0050] That is, Experiments 2, 5, and 6 show experiments in which the blade / classification rotor ratio (d b / d r ) was kept constant and the blade rotor diameter and the classification rotor diameter were changed.

[0051] Note that FIG. 5 is an image diagram without liquid leakage from the blade rotor mechanism section.

[0052] Note that the maximum peripheral speed of the classification rotor of the classifier 19 is 30 m / s, and the allowable pressure is 0.5 MPa, and the classification operation is performed within this range.

[0053] Also, as will be described later, since the differential pressure between the pressure from the blade rotor and the pressure from the classification rotor is such that the pressure generated by the classification rotor dominates the in-machine pressure, the actually measured pressure of the classification rotor is defined to be the same as the in-machine pressure, and the value obtained by subtracting the in-machine pressures of Experiments 1 to 6 from the actually measured pressure of the blade rotor was used. The in-machine pressure was determined by the pressure gauge 20.

[0054] Note that Equation 1 shows the theoretical pressure, and the differential pressure was obtained from Equation 4 (= Equation 3 - Equation 2), which was obtained by subtracting the experimentally obtained classification rotor actually measured pressure experimental formula (Equation 2) from the experimentally obtained blade rotor actually measured pressure experimental formula (Equation 3) as described in (5.1), (5.2), and (5.3) below.

[0055]

Equation

[0056] [Number]

[0057] [Number]

[0058] [Number]

[0059] Note that symbols, units, etc. are shown in Fig. **6**, and Fig. **7** shows the coefficient values of the classified rotor measured pressure experiment number (Equation **2**) obtained by experiments and the blade rotor measured pressure experiment formula (Equation **3**) as described later.

[0060] Also, S is represented by n·πd.

[0061] Also, the measured pressure of the blade rotor was obtained by continuously supplying a small amount of water into the classifier filled with water, measuring the supply pressure while increasing the rotational speed of the blade rotor with a predetermined blade rotor diameter alone, and defining the supply pressure as the measured pressure of the blade rotor, thereby obtaining the relationship between the blade rotor peripheral speed and the measured pressure of the blade rotor. Note that the supplied water was allowed to leak from the blade rotor mechanism part.

[0062] That is, in Experiments 7, 8, and 9, the blade rotor diameters were 0.054 m, 0.086 m, and 0.100 m, respectively. While increasing the rotational speed of the blade rotor alone, the internal pressure was measured by the pressure gauge **20**, and the relationship with the blade rotor peripheral speed was obtained with the internal pressure as the measured pressure of the blade rotor.

[0063] Note that the various conditions in Experiments 1 to 9 are shown in Table **1**.

[0064] **[Table 1]**

[0065] In addition, for Experimental Conditions 1 to 9, a small amount of water flow rate was used, and the stock solution supply rate Q = 2.78E-07 m 3 / s, and the rotation speed was 16.6 - 250 s -1 .

[0066] The results of the above Experiments 1 - 6 are shown in Table 2

[0067]

Table 2

[0068] As a result, from Experiments 2, 5, and 6, it was found that when the blade / classifier rotor ratio (d b / d r ) is constant, liquid leakage stops at the same classifier rotor peripheral speed

[0069] In addition, it was found that the larger the blade / classifier rotor ratio (d b / d r ), the lower the classifier rotor peripheral speed can be reduced to prevent liquid leakage

[0070] Therefore, from Experiments 1 - 6 above, the relationship between the blade / classifier rotor ratio (d b / d r ) and the classifier rotor peripheral speed at which liquid leakage stops is as shown in Figure 8. As the ratio (d b / d r ) increases, a relationship line M can be derived where the classifier rotor peripheral speed at which liquid leakage stops decreases. It was found that in the upper region B above the relationship line M, there is no liquid leakage, and in the lower region C, liquid leakage occurs

[0071] Note that in the region where the ratio (d b / d r ) is low, in order to prevent liquid leakage, as the ratio (d b / d r ) decreases, it is necessary to rapidly increase the classifier rotor peripheral speed

[0072] In addition, the classification rotor needs to be rotated at a high speed and has a large mechanical load. Therefore, it is preferable that the rotation speed is as low as possible.

[0073] And, for example, even if the blade / classification rotor ratio (d b / d r ) is increased, liquid leakage can be prevented. However, as the ratio (d b / d r ) is increased, the peripheral speed of the classification rotor required for preventing liquid leakage can be decreased, but from Equation 6 described later, the throughput will decrease.

[0074] Therefore, the ratio (d b / d r ) corresponding to the relationship line M at the classification rotor peripheral speed of 30 m / s at which the classification performance (throughput) of the classifier 19 can be maximized is 1.204. However, when the ratio (d b / d r ) is made larger than 1.204, in order to obtain the same classification performance (throughput) as during operation at 1.204, it is necessary to set the same classification rotor peripheral speed (30 m / s). In this case, when the blade rotor diameter is fixed, the classification rotor diameter becomes smaller, so it is necessary to increase the rotation speed of the classification rotor, resulting in a large mechanical load.

[0075] That is, as shown in Equation 6, when the classification rotor diameter becomes smaller, the classification rotor peripheral speed Sr decreases. Therefore, in order to maintain the classification performance (throughput), it is necessary to increase the rotation speed to maintain the peripheral speed.

[0076] Note that Table 3 shows the influence of the blade / classification rotor ratio (d b / d r ) at a classification rotor peripheral speed of 30 m / s on the classification performance by simulation. When the blade / classification rotor ratio (d b / d r ) is increased, the classification performance is constant, but it can be seen that the rotation speed of the classification rotor increases.

[0077]

Table 3

[0078] Also, when the circumferential speed of the classification rotor is 30 m / s and the blade / classification rotor ratio (d b / d r ) is kept constant, when the blade rotor diameter is increased, the classification performance remains constant, but the rotational speed of the classification rotor can be decreased. However, the blade rotor diameter is limited by the size of the classifier.

[0079] Also, from Table 3, it can be seen that when the circumferential speed of the classification rotor is 30 m / s, the throughput is the highest.

[0080] From the above, in order to design a classifier that can reduce the rotational speed of the classification rotor as much as possible to eliminate mechanical load, maximize the classification performance (throughput), and further prevent liquid leakage, the blade / classification rotor ratio (d b / d r ) corresponding to the relationship line M representing the liquid leakage stop at the maximum classification rotor circumferential speed of the classifier 19 can be obtained to design an optimal classifier.

[0081] And in the above experimental example, since the maximum classification rotor circumferential speed of the classifier 19 is 30 m / s, the blade / classification rotor ratio (d b / d r ) of 1.204 is the optimal value.

[0082] Note that the internal pressure at this time was obtained as 0.387 MPa from FIG. 13 described later, and it was confirmed that it was within the specification range (0.5 MPa) of the device.

[0083] According to the present invention, the correlation between the blade / classification rotor ratio (d b / d r ) and the classification rotor circumferential speed at the stop of liquid leakage is derived by experiments or the like. Based on this correlation, from the classification rotor circumferential speed required for the classifier to be developed in the future, the optimal blade rotor diameter (d b ) and the classification rotor diameter (d r) ratio (d b / d r ) is derived, and by using this value, it becomes possible to provide a classifier that does not leak liquid at a low rotor rotation speed.

[0084] (4. Comparison with a classifier using a mechanical seal in the shaft seal)

[0085] A classification performance comparison was made between a classifier using a mechanical seal 23 and a classifier having a non-contact seal portion of a classifier developed based on the present invention.

[0086] Fig. 9 shows a classifier 24 using a mechanical seal. Silica having a particle size shown in Fig. 10 was dispersed in water to 5 wt% to produce a raw material slurry and used. The particle size distribution of the raw material slurry is shown in Table 4.

[0087]

Table 4

[0088] The experimental method was to conduct a classification experiment using the silica slurry with a classifier using a mechanical seal and a developer, and confirm that the classification performance was equivalent.

[0089] The stock solution was supplied at 5.56E-07 m 3 / s, the coarse particles were withdrawn at 2.78E-07 m 3 / s with a metering pump, and the rest were recovered as fine particles at 2.78E-07 m 3 / s. The peripheral speed of the classification rotor was set to Sr = 7.96 m / s.

[0090] Then, the results obtained in the water operation in the developer were compared with the operation results using the silica slurry, and the operation results were evaluated.

[0091] The results are shown in Table 4. The symbols, units, conditions, etc. are shown in Fig. 11.

[0092] From Table 4, there was almost no difference in the classification performance between the classifier and the classifier using a mechanical seal for the shaft seal.

[0093] Also, using the stock solution (silica slurry) having the above particle size distribution, as shown in FIG. 12, the fine particle size distributions in the classifier and the classifier using a mechanical seal were almost the same.

[0094] In addition, the blade rotor mechanism method of the classifier had no liquid leakage from the shaft seal part during the classification operation, similar to the mechanical seal method of the conventional machine, and it was confirmed that this seal method could replace the mechanical seal.

[0095] In addition, in the comparison between the water operation of Experiment 1 and the silica slurry operation of this experiment in the classifier, the internal pressure of the machine was proportional to the density ratio of the liquid, and the silica slurry was about 1.03 times higher than water (silica 5% water slurry density ρs: 1028 kg / m 3 ).

[0096] Also, the peripheral speed of the classification rotor at the time of stopping liquid leakage was almost the same during water operation and silica slurry operation.

[0097] From the above, it was judged that the results obtained in the water operation could be similarly applied to the slurry operation.

[0098] Note that in the above Table 4, the theoretical classification particle size calculation formula used the classification cross-sectional area A = 0.7πd r T as 5. And in this 5, Q f was substituted with the fine particle recovery amount of 2.78E-07 m 3 / s for calculation.

Equation

[0099] (5. Explanation of various experimental conditions, etc.)

[0100] (5.1. Regarding the relationship between the peripheral speed Sr of the classification rotor and the internal pressure Pa (measured pressure Pr of the classification rotor))

[0101] Under the conditions of the blade rotor diameter and the classification rotor diameter in the above Experiments 1 to 6, while quantitatively supplying water into the machine from the stock solution supply port, the rotations of the blade rotor and the classification rotor fixed coaxially were gradually increased, and the relationship between the circumferential speed of the classification rotor and the pressure inside the machine obtained during this period was determined using the pressure gauge.

[0102] Note that the pressure inside the machine was dominated by the actually measured pressure of the classification rotor and set to the same pressure. The supplied water was discharged outside the machine from the coarse particle discharge port and the fine particle discharge port. In order to divide the respective discharge amounts equally, the water discharged from the coarse particle discharge port was discharged using a metering pump, and the remaining water was discharged from the fine particle discharge port.

[0103] It was found that the relationship between the circumferential speed of the classification rotor and the pressure inside the machine (the actually measured pressure of the classification rotor) as a result is the correlation shown in FIG. 13.

[0104] And from Equation 2, the number of blade rotors kb = 6.46E-7 and the multiplier α = 1.88 in the above number.

[0105] And from the correlation in FIG. 13, Equation 2 and FIG. 7 were obtained as the equations showing the relationship between the circumferential speed of the classification rotor and the pressure inside the machine.

[0106] And it was found that if the circumferential speed of the classification rotor is the same from Equation 2, the same pressure inside the machine is shown even if the classification rotor diameter changes.

[0107] Note that regarding the pressure inside the machine, as the circumferential speed of the classification rotor increases, the pressure inside the machine increases and rises up to 0.387 MPa at the maximum circumferential speed of 30 m / s of the developed classifier. And it was confirmed that it is 0.5 MPa or less of the allowable pressure of the device.

[0108] (5.2. Blade Rotor Circumferential Speed S b and the Actually Measured Pressure P of the Blade Rotor b Regarding the relationship)

[0109] In order to observe the actually measured pressure of the blade rotor in the blade rotor mechanism section, while quantitatively supplying water into the machine from the stock solution supply port, the blade rotor was installed alone, and under the conditions of the blade rotor diameter in Experiments 7 to 9, the peripheral speed of the blade rotor was gradually increased for each blade rotor, and the pressure at this time was obtained as the actually measured pressure of the blade rotor.

[0110] The actually measured pressure of the blade rotor was measured by the pressure gauge 20.

[0111] It was found that the relationship between the peripheral speed of the blade rotor and the actually measured pressure of the blade rotor as a result is the correlation shown in FIG. 14.

[0112] 。 And from the correlation in FIG. 14, Equation 3 and FIG. 7 were obtained as the equations showing the relationship between the peripheral speed of the blade rotor and the pressure inside the machine.

[0113] And from Equation 3, the number of blade rotors kb = 4.65E-7 and the multiplier α = 1.88 in the above equation (formula).

[0114] And even when the blade rotor diameter changed, if the peripheral speed of the blade rotor was the same, the same pressure was shown.

[0115] Note that while the theoretical value is proportional to the square of the peripheral speed of the blade rotor, the actually measured pressure of the blade rotor is to the 1.88th power of the peripheral speed of the blade rotor.

[0116] (5.3.d b / d r (Regarding the relationship between the rotor peripheral speed and the differential pressure (blade rotor pressure - pressure inside the machine) at the value)

[0117] Since the differential pressure is the pressure difference between the actually measured pressure of the blade rotor rotating coaxially and the pressure inside the machine (actually measured pressure of the classification rotor), the optimal value of d b / d r value 1.204 and d b / d rThe relationship between the classification rotor peripheral speed and the differential pressure when the classification rotor peripheral speed was increased to 30 m / s while changing the value was obtained from Equation (4) and shown in Fig. 15.

[0118] Note that Equation (4) was obtained from Equation (3) - Equation (2).

[0119] Also, since the differential pressure was minute and exceeded the measurement limit of the pressure gauge, it was calculated by Equation (4).

[0120] As a result, it was found that the differential pressure was a minute value.

[0121] Also, from Fig. 15, as the d b / d r value was constant and the classification rotor peripheral speed increased, the differential pressure increased, and liquid leakage from the blade rotor mechanism became less likely to occur.

[0122] Also, as the d b / d r value increased, the differential pressure at the same peripheral speed increased, and liquid leakage became less likely to occur.

[0123] Also, at the classification rotor peripheral speed required for liquid leakage to stop from the blade rotor in Table 2 above, the smaller the d b / d r value, the greater the differential pressure required for liquid leakage to stop from the blade rotor mechanism part, and it is necessary to increase the classification rotor peripheral speed to create that differential pressure.

[0124] Also, if the d b / d r value is constant, even if the rotor diameter changes, the classification rotor peripheral speed required for liquid leakage to stop is constant, and the differential pressure and the pressure inside the machine at that time are also constant.

[0125] (5.4. Regarding the influence of the blade / classification rotor diameter ratio (d b / d r ) value on the classification performance)

[0126] The classified particle size obtained by the centrifugal classifier is calculated from the Stokes' law. In the developed classifier, this classification operation is performed by the classification rotor, and the classification performance can be calculated from the Stokes' law. And the relationship among the supply amount, the fine particle recovery amount, and the classified particles is shown in Equation (5). And Q in Equation (5) f is indicated by the fine particle recovery amount.

[0127] Also, Equation (6) is shown as an equation that summarizes Equation (5) with the fine particle recovery amount Q f .

[0128]

Equation

[0129] And, in order to see the influence on the stock solution supply amount when the circumferential speed of the classification rotor and the classified particle size change under the condition that they are constant according to the above equation (formula), a simulation calculation is performed, and the results are summarized in Table 3 above. b / d r

[0130] Note that the various conditions are shown in FIG. 16.

[0131] From the above simulation calculation results, when the circumferential speed of the classification rotor is kept constant with respect to the change in the d b / d r value, the classified particle size and the stock solution supply amount of the classification performance became the same.

[0132] However, the developed classifier needs to rotate the classification rotor at a high speed. Even if the circumferential speed of the classification rotor is kept constant, since the mechanical load is large, an operation that can reduce the rotation speed as much as possible is desirable.

[0133] Therefore, from the above simulation calculation, since the classification rotor rotation speed can be reduced as the d b / d r value becomes smaller, it is judged that a d b / d r value of 1.204 with a low value is desirable.

[0134] Also, d​b / d r Even if the value is constant and the classification rotor diameter is increased, if the peripheral speed of the classification rotor is kept constant, the classification performance will be the same and the rotational speed of the classification rotor can be reduced. However, among those with a constant b / d r value, the one with the lowest rotational speed is b It is determined that a / d value of 1.204 is desirable.

[0135] According to the present invention, even for a classifier having a non-contact seal portion, it is possible to design a blade rotor mechanism portion without liquid leakage, and it is possible to provide a classifier with high classification performance (processing capacity) and low rotation.

Explanation of Signs

[0136] 1 Classifier 2 Housing 2a Ceiling plate 2b Through hole 3 Classification rotor 3a Discharge port 4 Rotating shaft 5 Rotating means 6 Through hole 7 Recovery chamber 8 Discharge port 9 Raw material tank 10 Supply pump 11 Supply port 12 Support portion 13 Disk 14 Blade 15 Slurry discharge chamber 16 Frame body 16a Plate 16b Plate 17 Classification blade 18 Classification chamber 19 Classifier 20 Pressure gauge 21 Groove 22 Straightening blade 23 Mechanical seal 24 Classifier​​

Claims

1. A housing to which a raw material containing particles to be classified is supplied, a classification rotor provided in the housing for classifying into fine particles and coarse particles, a rotating shaft of the classification rotor provided through the housing, rotating means for rotationally driving the rotating shaft, fine particle discharging means for discharging the classified fine particles that have flowed into the classification rotor to the outside of the housing, a discharge port for discharging the coarse particles that have not been classified by the classification rotor to the outside of the housing, feeding means for feeding the raw material to the housing, comprising sealing means for sealing the housing and the rotating shaft, the classification rotor is a rotatable frame body having an opening at the outer peripheral portion and a discharge port for discharging the fluid that has flowed into the inside from the opening to the outside, comprising a plurality of classification blades arranged at a desired interval in the circumferential direction at the outer peripheral side portion inside the frame body, the sealing means comprises a plate body fixed orthogonally to the rotating shaft and a plurality of blades fixed to the surface of the plate body and arranged at a desired interval in the circumferential direction and close to the inner surface of the housing, The outer diameter d of a blade rotor formed by arranging the plurality of blades in a circular shape b and the outer diameter d of the classification rotor r The ratio (d b / d r ) is the blade / classification rotor ratio (d b / d r ) obtained by experiments, and the correlation between the circumferential speed of the classification rotor at the time of stopping liquid leakage from the sealing means. A classifier characterized in that it is formed so as to have a blade / classification rotor ratio (d b / d r ) corresponding to the maximum circumferential speed of the classification rotor in design.

2. The classifier according to claim 1, wherein a plurality of straightening blades are provided at an inner side portion inside the classification blades in the frame body at a desired interval in the circumferential direction.

3. When the maximum classification rotor peripheral speed in the design is 30 m / s, the blade / classification rotor ratio (d b / d r ) is 1.204, and the classifier according to claim 1 or 2 is characterized by this.

4. A housing to which a raw material containing particles to be classified is supplied, a classification rotor provided in the housing for classifying into fine particles and coarse particles, a rotating shaft of the classification rotor provided through the housing, rotating means for rotationally driving the rotating shaft, fine particle discharging means for discharging the classified fine particles that have flowed into the classification rotor to the outside of the housing, a discharge port for discharging the coarse particles that have not been classified by the classification rotor to the outside of the housing, feeding means for feeding the raw material to the housing, comprising sealing means for sealing the housing and the rotating shaft, the classification rotor is a rotatable frame body having an opening at the outer peripheral portion and a discharge port for discharging the fluid that has flowed into the inside from the opening to the outside, comprising a plurality of classification blades arranged at a desired interval in the circumferential direction at the outer peripheral side portion inside the frame body, of the classifier comprising a plate body fixed orthogonally to the rotating shaft and a plurality of blades fixed to the surface of the plate body and arranged at a desired interval in the circumferential direction and close to the inner surface of the housing Blade / classification rotor ratio (d b / d r ) and a step of obtaining a correlation with the circumferential speed of the classification rotor at the time when liquid leakage from the sealing means stops, From this correlation, a step of obtaining a blade / classifier rotor ratio (d b / d r ) corresponding to the maximum classified rotor peripheral speed in design, and A classifier design method characterized by designing a classifier so that the required blade / classifier rotor ratio (d b / d r ) is obtained.

5. The design method of the classifier according to claim 4, characterized in that a plurality of straightening vanes are provided at a desired interval in the circumferential direction in the inner part of the frame body, inside the grading vanes.

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