JP2023081038A - Classifier and method for designing the same - Google Patents

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

(1. General description of the classifier)

As a classifier for classifying fine particles with high accuracy, classifying blades are spaced apart from each other in the circumferential direction (at desired intervals in the circumferential direction) and arranged radially from the center of rotation, or the longitudinal direction of the blades is There is an apparatus for classifying fine particles by rotating a classifying rotor arranged so that the center line in the width direction does not face the center of rotation at high speed.

In the classification, a fluid such as a gas or a liquid flows into a classifying chamber formed between adjacent classifying blades of a classifying rotor from the outer peripheral portion and moves toward the inner peripheral side. The centrifugal force F due to the high-speed rotation of the classifying rotor and the drag force R of the fluid flowing in the inner peripheral direction opposite to the direction of action of this centrifugal force are received, and both are balanced (F = R). Large-diameter coarse particles are discharged outside the classifying rotor, and small-diameter fine particles flow into the classifying rotor.

Further, in order to rotatably seal (enclose) the housing of the classifier and the rotating shaft provided through the housing, a mechanical seal portion that slidably supports the rotating shaft is not used. There is a classifier having a non-contact seal portion provided with a blade rotor mechanism (sealing means) having no sliding portion.

(2. Specific description of a classifier having a conventional non-contact seal)

17 to 21 show the conventional wet sealless classifier 1. The classifier 1 includes, for example, a cylindrical housing 2 having a diameter of 50 mm to 300 mm and a classifying rotor provided in the housing 2. 3, a rotating shaft 4 of the classifying rotor 3 provided vertically through a through hole 2b formed in the ceiling plate 2a of the housing 2, and a motor or the like for rotating the rotating shaft 4. a rotating means 5, and a through hole (fine particle discharging means) 6 formed in the rotating shaft 4 and extending in the axial direction for discharging the fine particles that have been classified by the classifying rotor 3 and flowed into the classifying rotor 3 to the outside of the housing 2. a recovery chamber 7 communicating with the other end of a through hole 6 formed in the rotary shaft 4 to guide the classified fine particles to a recovery tank (not shown); The raw material slurry is supplied from a discharge port 8 for discharging grains to the outside of the housing 2 and a raw material tank 9 storing raw material slurry containing particles to be classified with a size of 0.1 μm to 100 μm, for example, to the housing 2 by a supply pump 10. It consists of a supply port 11 for supplying inside.

Reference numeral 12 denotes a support portion for rotatably supporting the rotating shaft 4. As shown in FIG.

In addition, a blade rotor mechanism is provided to seal the through hole 2b of the ceiling plate 2a and the rotating shaft 4 in a non-contact, airtight (liquid-tight) manner.

For example, the blade rotor mechanism portion approaches the inner surface of the ceiling plate 2a of the housing 2 with its upper surface facing each other, and is perpendicular to the rotating shaft 4 passing through the through hole 2b formed in the ceiling portion 2a. and a disc plate 13 formed larger than the through hole 2b and fixed to the upper surface of the disc 13, spaced apart from each other in the circumferential direction (with a desired space in the circumferential direction). ), and blades 14 made up of a plurality of radially extending rods each having a rectangular cross-section, arranged radially from the center of rotation and close to the inner surface of the ceiling surface 2a.

The inner surface of the ceiling plate 2a is formed into a flat surface orthogonal to the penetrating rotating shaft 4 and faces the upper surface of the disk 13. As shown in FIG.

Further, for example, as shown in FIG. 19, each blade 14 has a desired length and is formed in the same shape, and is provided on the outer peripheral side of the upper surface of the disk 13. is provided so as to coincide with the outer edge of the disk 13 or be located slightly inside.

A plurality of blades 14 arranged in a circle form a blade rotor.

Reference numeral 15 denotes a slurry discharge chamber for recovering the leaked slurry when the slurry in the housing 2 leaks out of the housing 2 through the blade rotor mechanism and the through hole 2b. indicates

As shown in FIGS. 20 and 21, the classifying rotor 3 includes two identical disk-shaped plates 16a and 16b spaced vertically and arranged coaxially, and the center of the upper plate 16a. Between the outer peripheral side portions of the mutually facing surfaces of the two plates 16a and 16b and the frame 16 formed of the discharge port 3a communicating with the through hole 6 provided in the portion, at equal intervals in the circumferential direction, A plurality of classifying blades 17 are provided radially from the center of rotation, or are provided in the longitudinal direction of the blades so that the center line in the width direction does not face the center of rotation; In the inner part, there is a desired interval in the circumferential direction, and it is arranged radially from the center of rotation, or it is arranged so that the center line in the width direction, which faces the longitudinal direction of the blade, does not face the center of rotation A classifying chamber 18 is formed between the classifying blades 17, 17 adjacent to each other.

The straightening blades 22 are mainly for stabilizing the flow in the classifying rotor, but they may not be provided in some cases.

In the classifier 1, the raw material slurry from the raw material tank 9 is supplied into the housing 2 from the supply port 11 by the supply pump 10, and the high-speed rotating classifying rotor 3 provided in the classifier 1 The raw material slurry is classified into coarse-grained slurry and fine-grained slurry, and the coarse-grained slurry is discharged out of the housing 2 from the discharge port 8 of the housing 2 of the classifier 1. The particulate slurry that has flowed into the classifying rotor 3 from the opening of the part is fixed to the classifying rotor 3 through a discharge port 3a formed in the classifying rotor 3 and communicating with one end of the through hole 6 of the rotating shaft 4. It flows through the through hole 6 of the rotating shaft 4 and flows into the recovery chamber 7 from the other end of the through hole 6 and is recovered in the recovery tank.

Further, by rotating the disk 13 at a high speed, the inside of the housing 2 can be made to have a closed structure, and since the inner surface of the ceiling plate 2a and the blade 14 are spaced apart, they are like a mechanical seal. Troubles such as excessive wear, abrasion, and sticking can be eliminated.

For example, Patent Document 1 discloses a classifier having a non-contact seal portion.

Japanese Patent Application No. 2020-83855

In the above-mentioned classifying operation, liquid pressure is generated at the outer periphery of the classifying rotor due to centrifugal force directed toward the outer periphery. Must be sealed.

In addition, when the liquid in the machine reaches the outer periphery of the blade rotor rotating at high speed, centrifugal force acts toward the outer periphery at the same time, creating a state in which the liquid does not enter the blade rotor, thereby preventing the liquid from entering the blade rotor. An operation is performed to prevent leakage to the

That is, the blade rotor mechanism functions as a resistance body and exerts a sealing effect.

Regarding the pressure generated due to the structural difference between the blade rotor mechanism and the classifying rotor, the blade rotor mechanism has a gap between the blade rotor and the inner wall surface of the housing 2 as described above. Liquid leakage is more likely to occur and the generated (resistance) pressure/theoretical pressure is lower than the classifying rotor with impeller blades.

Therefore, if the diameter is the same, the pressure of the classifying rotor is higher than that of the blade rotor mechanism, so the liquid in the machine leaks from the blade rotor mechanism, and the sealing effect is lost. It was foreseen that it would be necessary to set the diameter of the blade rotor larger than the diameter of the classifying rotor in order to prevent this and provide a sealing effect without liquid leakage.

However, it was not clear to what extent.

Therefore, as a result of various experiments and studies, the inventors of the present application determined the relationship between the diameter of the blade rotor and the diameter of the classifying rotor, and the operating conditions at which liquid leakage does not occur from the blade rotor mechanism, and established the optimization of the blade rotor mechanism. .

In order 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 classifying rotor provided in the housing for classifying fine particles and coarse particles, and the housing a rotating shaft of the classifying rotor provided penetrating through, rotating means for rotationally driving the rotating shaft, and fine particle discharging means for discharging the classified fine particles that have flowed into the classifying rotor to the outside of the housing , a discharge port for discharging coarse particles not classified by the classifying 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 classifying rotor includes a rotatable frame having an opening on the outer periphery and a discharge port for discharging the fluid that has flowed into the inside from the opening; The sealing means comprises a plurality of classifying blades arranged at desired intervals in the circumferential direction, and the sealing means includes a plate fixed perpendicular to the rotating shaft and a circumferential an outer diameter d _b of a blade rotor formed by a plurality of blades arranged in a circular shape, comprising a plurality of blades adjacent to the inner surface of the housing and arranged with a desired spacing in the direction; , the ratio (d _b /d _r ) to the outer diameter d _r of the classifying rotor is the blade/classifying rotor ratio (d _b /d _r ) obtained by experiment, and when the leakage from the sealing means stops Based on the correlation with the peripheral speed of the classifying rotor, it is characterized by being formed so as to have a blade/classifying rotor ratio (d _b /d _r ) corresponding to the designed maximum classifying rotor peripheral speed.

Further, the blade/classifying rotor ratio (d _b /d _r ) is 1.204 when the designed maximum classifying rotor peripheral speed is 30 m/s.

Further, the method of designing the classifier of the present invention comprises: a housing to which a raw material containing particles to be classified is supplied; a classifying rotor provided in the housing for classifying fine particles and coarse particles; rotating shaft of the classifying rotor provided in the above; rotating means for rotationally driving the rotating shaft; fine particle discharging means for discharging the classified fine particles that have flowed into the classifying rotor and are classified to the outside of the housing; a discharge port for discharging coarse particles not classified by the 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 rotor includes a rotatable frame body having an opening on the outer periphery and a discharge port for discharging the fluid that has flowed into the interior from the opening to the outside. The sealing means is composed of a plurality of classifying blades arranged at desired intervals. The blade/classifying rotor ratio (d _b /d _r ) of the classifier consisting of a plurality of blades arranged close to the inner surface of the housing, and the time when liquid leakage from the sealing means stops A step of obtaining a correlation with the classifying rotor peripheral speed in the above, a step of obtaining a blade/classifying rotor ratio (d _b /d _r ) corresponding to the design maximum classifying rotor peripheral speed from the correlation, and the step of obtaining The classifier is designed such that the blade/classifier rotor ratio (d _b /d _r ) is equal to that of the classifier.

Further, it is characterized in that a plurality of rectifying vanes arranged at desired intervals in the circumferential direction are provided inside the frame inside the classifying vanes.

According to the present invention, even in a classifier having a non-contact seal part, it is possible to design a blade rotor mechanism part that does not leak liquid, and a classifier with high classification performance (throughput) and low rotation speed can be realized. can provide.

It is an explanatory longitudinal side view of a classifier used for designing the classifier of the present invention. FIG. 3 is an explanatory longitudinal side view of another classifier used for designing the classifier of the present invention; FIG. 11 is an explanatory plan view of still another classifier blade rotor (groove type) used to design the classifier of the present invention; FIG. 10 is an explanatory vertical cross-sectional side view of a blade rotor (groove type) of still another classifier used to design the classifier of the present invention; FIG. 4 is an image diagram of preventing liquid leakage from the blade rotor mechanism of the classifier. It is a figure which shows the dimension, a symbol, and a unit regarding description of a classifier. FIG. 4 is a diagram showing coefficient values obtained from experiments; FIG. 4 is a diagram showing the relationship between the blade/classifying rotor ratio (d _b /d _r ) and the classifying rotor circumferential speed when liquid leakage is stopped, which is obtained by experiment. It is an explanatory vertical side view of a classifier having a conventional mechanical seal. FIG. 10 is a diagram showing a stock solution particle size distribution in a comparative experiment; It is a figure which shows the dimension, a symbol, and a unit regarding description of a classifier. FIG. 4 is a diagram showing fine particle distribution in a comparative experiment; FIG. 4 is a diagram showing the relationship between the peripheral speed of the classifying rotor obtained by experiment and the internal pressure (measured pressure of the classifying rotor). FIG. 5 is a diagram showing the relationship between the blade rotor peripheral speed obtained by experiment and the blade rotor measured pressure. , and the relationship between the peripheral speed of the classifying rotor and the differential pressure with the blade/classifying rotor ratio (d _b /d _r ) as a parameter. It is a figure which shows an experimental condition. FIG. 2 is a schematic configuration diagram of a conventional classifier having a blade rotor mechanism; FIG. 10 is a longitudinal sectional side view for explaining a conventional classifier having a blade rotor mechanism; FIG. 19 is a cross-sectional view taken along line AA of FIG. 18; FIG. 19 is a cross-sectional view taken along line BB of FIG. 18; FIG. 2 is an explanatory vertical cross-sectional view of a classifying rotor of the classifier, omitting straightening blades.

An example of the mode for carrying out the present invention is shown below.

The same reference numerals are given to the same parts as the parts explained in the background art, and the explanation is omitted.

(3. Description of the present invention)

The present inventor operated the classifier while changing the diameter (d _b ) of the blade rotor and the diameter (d _r ) of the classifying rotor, and investigated the conditions under which liquid leakage stopped by experiments, etc., and found that the diameter of the blade rotor If the blade/classifying rotor ratio (d _b /d _r ) of (d _b ) and classifying rotor diameter (d _r ) is constant, even if the blade rotor diameter and classifying rotor diameter are changed, the same classifying rotor circumference It was found that the liquid does not leak at high speed.

It was also found that as the blade/classifying rotor ratio (d _b /d _r ) decreases, the peripheral speed of the classifying rotor needs to be increased in order to prevent liquid leakage.

It was also found that, when the blade/classifying rotor ratio (d _b /d _r ) is constant, the more the peripheral speed of the classifying rotor is increased, the less liquid leakage occurs.

In addition, the classification performance (throughput) is proportional to the square of the classification rotor peripheral speed, as shown in Equation 6 below, when the classifying particle diameter is constant. found to be higher.

Therefore, in the classifier to be developed (designed), the correlation between the blade/classifying rotor ratio (d _b /d _r ) and the peripheral speed of the classifying rotor when the liquid leakage stops is derived through experiments, etc., and the correlation is calculated. Originally, the ratio (d _b /d _r ) of the optimum blade rotor diameter (d _b ) that does not leak and the classifier rotor diameter (d _r ) at the maximum classification rotor peripheral speed in the design of the classifier to be developed from now on and found that the optimum classifier can be developed by using this value.

A specific description will be given below.

FIG. 1 shows an optimum condition setting classifier 19 having a blade rotor mechanism used for obtaining the optimum conditions of the classifier to be developed. Similarly, a pressure gauge 20 for measuring the pressure in the housing (inside the machine) 2 is provided.

The classifier 19 in FIG. 1 is an example in which the disk 13 of the blade rotor mechanism is fixed to the upper part of the classifying rotor 3. For example, as shown in FIG. Even if a rotor mechanism is provided, it has the same effect as the classifier 19 described above.

Further, as shown in FIGS. 3 and 4, 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 the blades 14 of the blade rotor mechanism. However, it has the same effect as the classifier 19 described above.

Further, the classifier 19 of the present embodiment shows an example in which the stock solution is introduced from the bottom.

Then, in order to find the optimum conditions for the classifier to be developed, the classifier 19 was used, the blade rotor diameter (d _b ) was set constant (0.054 m), and the classification rotor diameter (d _r ) was adjusted to Experiment 1 , 0.038 m, 0.043 m in experiment 2, 0.044 m in experiment 3, and 0.45 m in experiment 4. Water leaks out of the classifier from the part or the classifying rotor side, and while increasing the number of revolutions of the classifying rotor, measure the pressure inside the machine with the pressure gauge 20, and visually check from the blade rotor mechanism to the outside. The peripheral speed of the classifying rotor was obtained when the water leakage stopped. When the rotation speed of the classifying rotor is increased, at first, water leakage occurs only from the blade rotor mechanism. Water will be discharged outside.

That is, experiments 1 to 4 show experiments in which the blade/classifying rotor ratio (d _b /d _r ) was varied.

In addition, in Experiment 5, the blade rotor diameter was 0.086 m and the classification rotor diameter was 0.0685 m so that the blade / classifying rotor ratio (d _b /d _r ) in Experiment 2 was the same ratio (1.256). In Experiment 6, the diameter of the blade rotor was set to 0.100 m, and the diameter of the classifying rotor was set to 0.0796 m. The pressure was measured, and the peripheral speed of the classifying rotor when water leakage from the blade rotor mechanism to the outside stopped was determined by visual inspection.

That is, Experiments 2, 5, and 6 show experiments in which the blade/classifying rotor ratio (d _b /d _r ) was kept constant, and the blade rotor diameter and the classifying rotor diameter were varied.

In addition, FIG. 5 is an image diagram of no liquid leakage from the blade rotor mechanism.

The classifier 19 has a maximum classification rotor peripheral speed of 30 m/s and an allowable pressure of 0.5 MPa, and the classification operation is performed within these ranges.

In addition, as will be described later, the difference between the pressure from the blade rotor and the pressure from the classifying rotor is the pressure generated in the classifying rotor that governs the pressure inside the machine. It was defined as a value obtained by subtracting the internal pressure of Experiments 1 to 6 from the measured pressure of the blade rotor. The pressure inside the machine was determined by the pressure gauge 20 described above.

In addition, Equation 1 is a formula showing the theoretical pressure, and the differential pressure is obtained from experiments as described later in (5.1.), (5.2.), and (5.3.). The pressure empirical formula (Equation 2) was obtained from the equation 4 (=Equation 3-Equation 2) obtained by subtracting from the blade rotor measured pressure empirical equation (Equation 3) obtained from the experiment.

Note that symbols, units, etc. are shown in FIG. indicates the coefficient value.

Also, S is represented by n·πd.

In addition, the measured pressure of the blade rotor is obtained by continuously supplying a small amount of water into the classifier filled with water, and measuring the supply pressure while increasing the rotation speed of the blade rotor of a predetermined blade rotor diameter alone. The blade rotor measured pressure was defined as the relationship between the blade rotor peripheral speed and the blade rotor measured pressure. The supplied water was made to leak from the blade rotor mechanism.

That is, in Experiment 7, Experiment 8, and Experiment 9, the blade rotor diameter was set to 0.054 m, 0.086 m, and 0.100 m, respectively, and the blade rotor alone was increased in rotation speed. was measured, and the relationship with the peripheral speed of the blade rotor was obtained using the in-machine pressure as the actually measured pressure of the blade rotor.

Table 1 shows various conditions in Experiments 1 to 9.

Experiments 1 to 9 were conducted under the conditions of a very small amount of water flow rate, a stock solution supply rate Q of 2.78E-07 m ³ /s, and a rotational speed of 16.6 to 250 s ^-1 .

Table 2 shows the results of Experiments 1 to 6.

As a result, from Experiments 2, 5 and 6, it was found that if the blade/classifying rotor ratio (d _b /d _r ) is constant, liquid leakage stops at the same classifying rotor peripheral speed.

It was also found that the higher the blade/classifier rotor ratio (d _b /d _r ), the lower the classifier rotor peripheral speed in order to prevent liquid leakage.

Therefore, from the above experiments 1 to 6, the relationship between the blade/classifying rotor ratio (d _b /d _r ) _and the classifying rotor peripheral speed when the liquid leakage stopped is as shown in FIG. A relationship line M can be derived in which the classifier rotor peripheral speed at the time of stoppage of liquid leakage decreases as _r ) increases. I found out.

In the region where the ratio (d _b /d _r ) is low, in order to prevent liquid leakage, it is necessary to rapidly increase the peripheral speed of the classifying rotor as the ratio (d _b /d _r ) decreases. be.

Further, the classifying rotor must be rotated at a high speed, which imposes a large mechanical burden on the classifier.

For example, even if the blade/classifying rotor ratio (d _b / _{d r} ) is increased, liquid leakage can be _prevented . Although the rotor peripheral speed can be lowered, the processing amount is lowered from Equation 6 described later.

Therefore, the ratio (d _b /d _r ) corresponding to the relationship line M at a classifying rotor peripheral speed of 30 m/s that can maximize the classifying performance (throughput) of the classifier 19 is 1.204. When the ratio (d _b /d _r ) is greater than 1.204, in order to obtain the same classification performance (throughput) as in the operation of 1.204, the same classification rotor peripheral speed (30 m/s) In this case, if the diameter of the blade rotor is constant, the classifying rotor diameter will be small, so the number of revolutions of the classifying rotor must be increased, which imposes a heavy mechanical load.

That is, as shown in Equation 6, when the diameter of the classifying rotor becomes small, the peripheral speed Sr of the classifying rotor decreases. There must be.

Table 3 shows the influence of the blade _/ classifying rotor ratio (d _b /d _r ) on the classification performance at a classification rotor peripheral speed of 30 m/s by simulation. It can be seen that when d _r ) is increased, the classifying performance is constant, but the rotation speed of the classifying rotor increases.

In addition, when the blade/classifying rotor ratio (d _b /d _r ) is constant at a classification rotor peripheral speed of 30 m/s, the classification performance is constant when the blade rotor diameter is increased, but the classification rotor rotation speed can be made smaller. However, the blade rotor diameter is limited due to the size of the classifier.

Also, from Table 3, it can be seen that the processing amount is the largest when the peripheral speed of the classifying rotor is 30 m/s.

From the above, in order to design a classifier that minimizes the classifying rotor rotation speed as much as possible to eliminate the mechanical burden, maximizes the classifying performance (throughput), and does not cause liquid leakage, it is necessary to classify By determining the blade/classifying rotor ratio (d _b /d _r ) corresponding to the relationship line M, which represents the time when liquid leakage stops, at the maximum classifying rotor peripheral speed of the classifier 19, an optimum classifier can be designed.

In the above experimental example, _the maximum classification rotor peripheral speed of the classifier 19 is 30 m/ _s . value.

It should be noted that the internal pressure at this time was found to be 0.387 MPa from FIG.

According to the present invention, the correlation between the blade/classifying rotor ratio (d _b /d _r ) and the peripheral speed of the classifying rotor when the liquid leakage stops is derived through experiments, etc., and based on the correlation, future development From the classification rotor peripheral speed required for the classifier, derive the optimum blade rotor diameter (d _b ) and classification rotor diameter (d _r ) ratio (d _b /d _r ) that does not leak, and use this value. As a result, it is possible to provide a classifier that does not leak even at a low rotor speed.

(4. Comparison with a classifier using a mechanical seal for shaft sealing)

Classification performance was compared between a classifier using the mechanical seal 23 and a classifier having a non-contact seal portion developed based on the present invention.

FIG. 9 shows a classifier 24 using a mechanical seal. Silica having the particle size shown in FIG. 10 was dispersed in water to 5 wt % to prepare and use a raw material slurry. Table 4 shows the particle size of the raw material slurry.

As an experimental method, a classifying experiment using the silica slurry was conducted with a classifier using a mechanical seal and a developed machine, and it was confirmed that the classifying performance was the same.

The undiluted solution was supplied at 5.56E-07m ³ /s, the coarse particles were drawn out with a metering pump at 2.78E-07m ³ /s, and the remaining fine particles were collected at 2.78E-07m ³ /s. The peripheral speed of the classifying rotor was Sr=7.96 m/s.

Then, we compared the results obtained in water operation with the developed machine and the results obtained with silica slurry, and evaluated the operation results.

The results are shown in Table 4. Symbols, units, conditions, etc. are shown in FIG.

From Table 4, there was almost no difference in classification performance between the classifier using a mechanical seal for shaft sealing and the developed machine.

Moreover, as shown in FIG. 12, the fine particle size distribution of the developed machine and the classifier using the mechanical seal were almost the same, using the undiluted solution (silica slurry) having the above particle size distribution.

In addition, the blade rotor mechanism method of the developed machine does not leak from the shaft seal during classification operation, just like the mechanical seal method of the conventional machine, and it was confirmed that this seal method will replace the mechanical seal.

Also, in a comparison of water operation in Experiment 1 and silica slurry operation in this experiment, the internal pressure of the developed machine is proportional to the density ratio of the liquid, and silica slurry is about 1.03 times higher than water. (Silica 5% water slurry density ρs: 1028 kg/m ³ ).

In addition, the peripheral speed of the classifying rotor when the liquid leakage stopped was almost the same between the water operation and the silica slurry operation.

From the above, it was determined that the results obtained in water operation were equally applicable to slurry operation.

The theoretical classification particle size calculation formula in Table 4 uses Equation 5 with the classification cross-sectional area A=0.7πd _r T obtained by subtracting the cross-sectional area of the classifying blade. Then, in Equation 5, calculation was performed by substituting the fine particle recovery amount of 2.78E-07 m ³ /s for Q _f .

(5. Description of various types, experimental conditions, etc.)

(5.1. Regarding the relationship between the classifying rotor peripheral speed Sr and the internal pressure Pa (measured classifying rotor pressure Pr))

Under the conditions of the blade rotor diameter and classifying rotor diameter in Experiments 1 to 6, while supplying a constant amount of water into the machine from the stock solution supply port, the rotation of the coaxially fixed blade rotor and classifying rotor was gradually increased, Using the pressure gauge, the relationship between the peripheral speed of the classifying rotor and the in-machine pressure was obtained.

The pressure inside the machine is governed by the measured pressure of the classifying rotor, so the same pressure was used. Then, the supplied water is discharged from the coarse particle discharge port and the fine particle discharge port to the outside of the machine. The rest of the water was discharged through the fines outlet.

As a result, it was found that the relationship between the peripheral speed of the classifying rotor and the in-machine pressure (measured pressure of the classifying rotor) was the correlation shown in FIG.

From Equation 2, the blade rotor number kb=6.46E-7 and the multiplier α=1.88.

Then, from the correlation in FIG. 13, Equation 2 and FIG. 7 were obtained as equations showing the relationship between the peripheral speed of the classifying rotor and the in-machine pressure.

From Equation 2, it was found that if the peripheral speed of the classifying rotor is the same, the internal pressure is the same even if the diameter of the classifying rotor is changed.

As for the pressure inside the machine, it was found that as the peripheral speed of the classifying rotor increased, the pressure inside the machine rose to 0.387 MPa at the maximum peripheral speed of the developed classifier of 30 m/s. Then, it was confirmed that the allowable pressure of the apparatus was 0.5 MPa or less.

(5.2. Regarding the relationship between the blade rotor peripheral speed S _b and the blade rotor measured pressure P _b )

In order to see the measured pressure of the blade rotor generated in the blade rotor mechanism, the blade rotor was attached independently while supplying a constant amount of water from the raw solution supply port into the machine, and under the conditions of the blade rotor diameter in Experiments 7 to 9, each blade In the rotor, the peripheral speed of the blade rotor was gradually increased, and the pressure at this time was obtained as the actually measured pressure of the blade rotor.

The measured blade rotor pressure was measured by the pressure gauge 20 .

As a result, it was found that the relationship between the blade rotor peripheral speed and the blade rotor measured pressure is the correlation shown in FIG. 14 .

.
From the correlation in FIG. 14, Equation 3 and FIG. 7 were obtained as equations showing the relationship between the blade rotor peripheral speed and the internal pressure.

From Equation 3, the blade rotor number kb=4.65E-7 and the multiplier α=1.88 in the above equation (formula).

Even if the diameter of the blade rotor was changed, the pressure was the same as long as the peripheral speed of the blade rotor was the same.

While the theoretical value is proportional to the square of the blade rotor peripheral speed, the measured pressure of the blade rotor was 1.88 power of the blade rotor peripheral speed.

(5.3. Relationship between rotor peripheral speed and differential pressure (blade rotor pressure - machine pressure) at _{d b} /d _r value)

Since the differential pressure is the pressure difference between the measured pressure of the blade rotor rotating on the same axis and the internal pressure (measured pressure of the classifying rotor), the optimal value and the obtained d _b /d _r value of 1.204 and d _b /d _r FIG. 15 shows the relationship between the classifying rotor peripheral speed and the differential pressure when the classifying rotor peripheral speed is increased to 30 m/s by changing the values.

Note that Equation 4 was obtained from Equations 3-2.

Also, the differential pressure is so small that it exceeds the measurement limit of the pressure gauge, so it was calculated using Equation 4.

As a result, the differential pressure was found to be a very small value.

Further, from FIG. 15, the differential pressure increased as the classifying rotor peripheral speed was increased while the d _b /d _r value was constant, and liquid leakage from the blade rotor mechanism was less likely to occur.

Also, the larger the d _b /d _r value, the larger the differential pressure at the same peripheral speed, and the less likely the liquid will leak.

Also, from Table 2 above, the smaller the value of d _b /d _r at the classifying rotor peripheral speed required to stop liquid leakage from the blade rotor, the more it is necessary to stop liquid leakage from the blade rotor mechanism. Therefore, the classifying rotor peripheral speed must be increased in order to create the differential pressure.

Also, if the d _b /d _r value is constant, the peripheral speed of the classifying rotor required to stop liquid leakage is constant even if the rotor diameter changes, and the differential pressure and internal pressure at that time are also constant.

(5.4. Influence of blade/classifying rotor diameter ratio (d _b /d _r ) value on classification performance)

The classified particle size obtained by the centrifugal classifier is calculated from the Stokes formula. In the developed classifier, this classifying operation is performed by a classifying rotor, and the classifying performance can be calculated from the Stokes equation. The relation between the supplied amount of collected fine particles and the classified particles is shown in Equation 5 above. Q _f in Equation 5 is indicated by the amount of collected fine particles.

Further, Equation 6 is shown as an equation in which Equation 5 is summarized by the fine particle recovery amount _Qf .

Then, according to the above formula (formula), a simulation calculation was performed to see the effect on the stock solution supply amount when _the peripheral speed of the classifying rotor and the classifying particle _size were changed under constant conditions. summarized in

Various conditions are shown in FIG.

From the above simulation calculation results, if the peripheral speed of the classifying rotor is kept constant with respect to changes in the d _b /d _r value, the classified particle size and the feed amount of the stock solution in the classifying performance remain the same.

However, the developed classifier needs to rotate the classifying rotor at high speed, and even if the peripheral speed of the classifying rotor is kept constant, the mechanical load is large.

Therefore, _from the above simulation _calculation , the smaller the d _b /d _r value, the lower the classifying rotor rotation speed.

Further, even if the d _b /d _r value is constant and _the diameter of the classifying rotor is increased, if the peripheral speed of the classifying rotor is kept constant, the classification performance will be the same and the number of revolutions of the classifying rotor can be reduced _. It is determined that d _b /d value of 1.204, which is the lowest rotational speed among constant values, is desirable.

According to the present invention, even in a classifier having a non-contact seal, it is possible to design a blade rotor mechanism that does not leak liquid, and to provide a low-rotation classifier with high classification performance (throughput). can provide.

1 classifier 2 housing 2a ceiling plate 2b through hole 3 classifying 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 16a Plate 16b Plate 17 Classifying blade 18 Classifying chamber 19 Classifier 20 Pressure gauge 21 Groove 22 Rectifying blade 23 Mechanical seal 24 Classifier

Claims (5)

a housing supplied with a raw material containing particles to be classified;
a classifying rotor provided in the housing for classifying fine particles and coarse particles;
a rotating shaft of the classifying rotor provided through the housing;
a rotating means for rotating the rotating shaft;
fine particle discharging means for discharging the classified fine particles, which have flowed into the classifying rotor, to the outside of the housing;
a discharge port for discharging coarse particles that have not been classified by the classifying rotor to the outside of the housing;
supply means for supplying the raw material to the housing;
A sealing means for sealing the housing and the rotating shaft,
The classifying rotor has an opening on its outer periphery, and a rotatable frame body having a discharge port for discharging the fluid that has flowed into the inside from the opening to the outside;
A plurality of classifying blades arranged at desired intervals in the circumferential direction on the outer peripheral side of the frame,
The sealing means includes a plate fixed perpendicularly to the rotating shaft, and an inner surface of the housing fixed to the surface of the plate and arranged at a desired interval in the circumferential direction. consists of multiple blades and
The ratio (d _b /d _r ) between the outer diameter d _b of the blade rotor formed by arranging the plurality of blades in a circular shape and the outer diameter d _r of the classifying rotor is obtained by experiments. From the correlation between the classifying rotor ratio (d _b /d _r ) and the classifying rotor peripheral speed when the liquid leakage from the sealing means stops, the blade / classifying rotor ratio (d _b /d _r ). 2. The classifier according to claim 1, wherein a plurality of rectifying blades arranged at desired intervals in the circumferential direction are provided inside said frame inside said classifying blades. 3. The classifier according to claim 1 or 2, wherein the blade/classifier rotor ratio (d _b /d _r ) is 1.204 when the designed maximum classifier rotor peripheral speed is 30 m/s. machine. a housing supplied with a raw material containing particles to be classified;
a classifying rotor provided in the housing for classifying fine particles and coarse particles;
a rotating shaft of the classifying rotor provided through the housing;
a rotating means for rotating the rotating shaft;
fine particle discharging means for discharging the classified fine particles, which have flowed into the classifying rotor, to the outside of the housing;
a discharge port for discharging coarse particles that have not been classified by the classifying rotor to the outside of the housing;
supply means for supplying the raw material to the housing;
A sealing means for sealing the housing and the rotating shaft,
The classifying rotor has an opening on its outer periphery, and a rotatable frame body having a discharge port for discharging the fluid that has flowed into the inside from the opening to the outside;
A plurality of classifying blades arranged at desired intervals in the circumferential direction on the outer peripheral side of the frame,
The sealing means includes a plate fixed perpendicularly to the rotating shaft, and an inner surface of the housing fixed to the surface of the plate and arranged at a desired interval in the circumferential direction. A step of obtaining a correlation between a blade/classifying rotor ratio (d _b /d _r ) of a classifier comprising a plurality of blades and a peripheral speed of the classifying rotor when liquid leakage from the sealing means stops;
determining the blade/classifier rotor ratio (d _b /d _r ) corresponding to the maximum designed classifier rotor peripheral speed from the correlation;
A method for designing a classifier, characterized by designing the classifier so as to achieve the determined blade/classifying rotor ratio (d _b /d _r ). 5. The method for designing a classifier according to claim 4, wherein a plurality of rectifying blades arranged at desired intervals in the circumferential direction are provided inside said frame inside said classifying blades. .

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