JP2014073469A - Powder screening device and power screening method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce clogging of a screening mesh with a simple structure to improve classification efficiency.SOLUTION: A powder screening device comprises: a net sieve including at least one sieve which sieves powder; an actuator which vibrates the net sieve; a sensor which obtains information about classification efficiency of the sieve; and a controller which generates a driving signal to drive the actuator on the basis of the information about the classification efficiency obtained by the sensor.

Description

  The present invention relates to a powder sieving apparatus and a powder sieving method for sieving powder using a sieve.

  In a steelmaking line in an ironmaking plant, impurities such as sulfide, phosphorus and carbon in hot metal are taken into slag by a chemical reaction to produce high purity molten steel. Among them, in the desulfurization process, there is a technique called KR (Kanbara Reactor) method, in which a desulfurizing agent mainly composed of calcium oxide is added to a ladle containing hot metal, stirred with a blade made of refractory, and sulfide is removed. Generally adopted. The desulfurization slag produced in the desulfurization process contains a large amount of unreacted calcium oxide or free lime.

  When recycling desulfurized slag, it is important to accurately determine the particle size distribution of these substances. Conventionally, various methods have been proposed as means for classifying fine powder with high efficiency. As one of the classification methods, there is known a vibration sieve classification method in which powder is classified by swinging and rotating the sieve layer. However, in the vibration sieve classification system, powder aggregates and segregates due to the influence of moisture acting between the powder particles, van der Waals force, electrostatic force, etc., and clogging of the sieve occurs. This causes a problem that the classification efficiency is lowered.

  Conventionally, various techniques for reducing or eliminating clogging of the sieve have been proposed for such problems.

  In Patent Document 1, a brush disk in which a brush is implanted is arranged on a mesh screen, and the brush disk is allowed to move by rotating the mesh screen in a horizontal swinging manner. A scraping technique is disclosed. Patent Document 1 discloses that an annular resonance ring is provided at the bottom of the sieve layer and ultrasonic vibration is applied to the resonance ring.

  Patent Document 2 discloses that mesh screens having different mesh sizes are arranged in multiple stages, and backwash air is blown onto the mesh screen to prevent the mesh screen from being clogged.

Japanese Patent No. 2882581 JP 2002-35698 A

  However, in the apparatus of Patent Document 1, when the apparatus is used for a long time, the brush may be damaged or worn and mixed into the separated particles as a foreign substance. In addition, since the brush must be replaced regularly, there is a problem that the running cost increases.

  Further, the apparatus of Patent Document 2 requires a large facility such as a blower for generating backwash air, and has a problem that initial cost and running cost increase. In addition, it is necessary to install a bug filter so that fine powder does not enter the blower, and it is necessary to periodically maintain the bag filter.

  Therefore, an object of the present invention is to reduce clogging of a sieve screen with a simple configuration and improve classification efficiency and throughput.

In order to achieve the above object, the present invention has the following features.
[1] A mesh sieve provided with at least one sieve for sieving powder;
An actuator for applying vibration to the mesh screen;
A sensor for acquiring information on the classification efficiency of the sieve;
A powder sieving apparatus comprising a control unit that generates a drive signal for driving the actuator based on information on the classification efficiency acquired by the sensor.
[2] The powder sieving device according to [1], wherein the control unit controls a frequency of a drive signal for driving the actuator based on information on the classification efficiency acquired by the sensor.
[3] The mesh screen includes a first screen and a second screen,
The sensor includes a first sensor that acquires information on the classification efficiency of the first sieve, and a second sensor that acquires information on the classification efficiency of the second sieve,
The actuator is provided in common for the first sieve and the second sieve,
The control unit is configured to generate a drive signal for driving the actuator based on information related to the classification efficiency acquired by the first sensor, and information related to the classification efficiency acquired by the second sensor. And a second mode for generating a drive signal for driving the actuator,
The powder sieving apparatus according to [1] or [2], wherein the first mode and the second mode are switched at a predetermined time.
[4] The powder sieving device according to any one of [1] to [3], wherein the frequency of the drive signal is 10 Hz to 20 kHz.
[5] For a mesh sieve provided with at least one sieve for sieving powder, obtain information on the classification efficiency of the sieve,
A powder sieving method for generating a drive signal for driving an actuator that applies vibration to the sieve based on the acquired information on the classification efficiency.
[6] The powder sieving method according to [5], wherein the frequency of a drive signal for driving the actuator is controlled based on the acquired information on the classification efficiency.
[7] The mesh screen includes a first screen and a second screen,
The actuator is provided in common for the first sieve and the second sieve,
Obtain information on the classification efficiency of the first sieve,
Obtain information on the classification efficiency of the second sieve,
Based on information on the classification efficiency of the first sieve, a first mode for generating a drive signal for driving the actuator, and on the basis of information on the classification efficiency of the second sieve, a drive signal for driving the actuator is generated. The powder sieving method according to [5] or [6], wherein the second mode is switched at a predetermined time.
[8] The powder sieving method according to any one of [5] to [7], wherein the frequency of the drive signal is 10 Hz to 20 kHz.

  According to the present invention, clogging of a sieve screen can be reduced with a simple configuration, and classification efficiency and throughput can be improved.

It is a figure which shows the structure of the powder sieving apparatus which concerns on embodiment of this invention. It is a figure which shows the drive signal of the powder sieving apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  The powder sieving device according to the present embodiment includes a mesh screen 1, an actuator 2, a coupling material 3, and a control unit 8. The control unit 8 includes an amplifier 4, a calculation unit 5, a display unit 6, and a function generator 7. The powder sieved by the powder sieving device is, for example, a powder of 10 mm or less.

  The mesh screen 1 has three-stage screens 1a, 1b, 1c and a screen receiver 1d. The sieves 1a, 1b, and 1c are installed at a predetermined interval in the vertical direction. The sieves 1a, 1b, and 1c have a mesh for sieving the powder, and the meshes of the sieves 1a, 1b, and 1c are arranged so as to become finer as they go downward. The sieve receiver 1d is arranged under the lowermost sieve 1c and receives the powder that has passed through all the sieves 1a, 1b, and 1c and dropped downward.

  The actuator 2 is attached to the mesh screen 1 via a coupling material 3. The actuator 2 is controlled by the control unit 8 to vibrate at an arbitrary frequency. The mesh screen 1 on which the actuator 2 is installed vibrates at an arbitrary frequency. In the present embodiment, the actuator 2 is shared by the plurality of sieves 1a, 1b, and 1c, and all the sieves 1a, 1b, and 1c vibrate at the same frequency due to the vibration of the actuator 2. The control unit 8 generates a drive signal for driving the actuator 2. The control unit 8 generates a driving signal optimum for each of the sieves 1a, 1b, and 1c, and switches the driving signal to a driving signal optimum for each of the sieves 1a, 1b, and 1c every predetermined time.

  The coupling material 3 is preferably made of grease or water.

  The control unit 8 includes an amplifier 4, a function generator 7, and a display unit 6. The amplifier 4 amplifies the drive signal generated by the function generator 7 to a predetermined amplitude, and outputs the amplified signal to the actuator 2 as a drive signal. The function generator 7 generates a drive signal for controlling the actuator 2, and outputs the generated drive signal to the actuator 2 via the amplifier 4.

  The display unit 6 displays control information of the powder sieving device such as a drive signal generated by the function generator 7.

  The sensor 9 includes sensors 9a, 9b, and 9c. Sensors 9a, 9b, and 9c are provided for each of the sieves 1a, 1b, and 1c, and acquire information related to classification efficiency. Specifically, the sensor 9a is provided in the sieve 1a and acquires information on the classification efficiency of the sieve 1a. The sensor 9b is provided in the sieve 1b and acquires information related to the classification efficiency of the sieve 1b. The sensor 9c is provided in the sieve 1c and acquires information related to the classification efficiency of the sieve 1c. The classification efficiency is defined as the amount of powder below the sieve (sieving tray 1d) after sieving for a predetermined time / the amount of powder below the sieve in the sample (one sieve).

  Information on classification efficiency can be acquired as various parameters. For example, if the sieves 1a, 1b, and 1c vibrate greatly, it is considered that a large amount of powder is sieved and the classification efficiency increases. Therefore, the horizontal direction and / or vertical direction displacement and acceleration of the sieves 1a, 1b, and 1c can be acquired as information on the classification efficiency.

  In addition, a weight sensor that detects the weight of the sieves 1a, 1b, and 1c is provided, and the weight of the powder that can be sieved from the top to the bottom using the respective meshes is acquired as information on the classification efficiency. May be.

  In addition, a camera may be installed on and / or below the sieve, a powder image may be captured, and an image acquired by the camera may be acquired as information regarding classification efficiency. In this case, it is possible to measure the approximate amount of powder that can be screened from the top to the bottom of the screen from the image acquired by the camera.

  Thus, the sensor 9 can be configured as a sensor that acquires various data. The sensor 9 may be a combination of two or more types of sensors. Further, since it is only necessary to be able to perform feedback control of the drive signal based on the detection value of the sensor 9, a different sensor may be used for each of the sieves 1a, 1b, and 1c. Further, a weight sensor may be provided on the sieve tray 1d. Moreover, you may comprise so that the information regarding the classification efficiency of several sieve 1a, 1b, 1c may be detected by one sensor.

  Hereinafter, the sensors 9a, 9b, and 9c will be described as displacement sensors. In the present embodiment, a plurality of displacement sensors are provided at lattice points on the respective sieve surfaces of the sieves 1a, 1b, and 1c. Displacement can be acquired as two-dimensional information by providing a plurality of displacement sensors at lattice points on the sieve surface. Information regarding the classification efficiency of the sieves 1a, 1b, and 1c acquired by the sensors 9a, 9b, and 9c is output to the calculation unit 5.

  The calculating part 5 produces | generates a drive signal based on the information regarding the classification efficiency of the sieves 1a, 1b, 1c acquired by the sensors 9a, 9b, 9c. Specifically, the calculation unit 5 calculates the frequency of the drive signal generated by the function generator 7 based on the information regarding the classification efficiency of the sieves 1a, 1b, and 1c acquired by the sensors 9a, 9b, and 9c. Control is performed so that the classification efficiencies 1b and 1c are optimized. The function generator 7 changes the amplitude of the frequency of the drive signal in accordance with a control instruction from the calculation unit 5.

  Next, the drive signal generated by the function generator 7 and amplified by the amplifier 4 will be described. FIG. 2 is a diagram illustrating a drive signal generated by the function generator 7. As described above, the drive signal is set so that the classification efficiencies of the respective sieves 1a, 1b, and 1c are optimum, and is switched every predetermined time.

  Specifically, in the first mode, the control unit 8 generates a drive signal having a frequency that maximizes the classification efficiency of the sieve 1a for a certain period of time and outputs it to the actuator 2. In the second mode, the classification efficiency of the sieve 1b. Is generated for a certain period of time and output to the actuator 2. In the third mode, a driving signal having a frequency at which the classification efficiency of the sieve 1c is maximized is generated for a certain period of time and output to the actuator 2. Thereby, the drive signal of the optimal frequency of the some sieves 1a, 1b, and 1c is generable with the one actuator 2. FIG. As described above, the control unit 8 switches the operation from the first mode to the third mode, and generates an optimal drive signal for a plurality of sieves by using one actuator 2.

  The drive signal is preferably a rectangular wave as shown in FIG. By making the rectangular wave, the vibration direction of the sieve can be sharply changed at the edge of the rectangular wave, and the classification efficiency can be improved. Furthermore, the frequency of the drive signal is preferably 10 Hz to 20 kHz. By setting the frequency of the drive signal to 10 Hz to 20 kHz, the sieve can be vibrated with a certain level of amplitude, and sieving can be performed efficiently.

  The length of each section from the first mode to the third mode may be the same or different. In the example of FIG. 2, the first mode to the third mode are shown once, but the first mode to the third mode may be repeatedly switched. In this case, it is not necessary to repeat the first mode to the third mode the same number of times. For example, the first mode may be set only once, and the second mode and the third mode may be repeated twice.

  Next, the effect of this embodiment configured as described above will be described. In the powder sieving device according to the present embodiment, the frequency of the drive signal is feedback-controlled so that the classification efficiency of each of the sieves 1a, 1b, and 1c is optimal (or maximum). Therefore, it is possible to improve the powder classification efficiency and throughput by efficiently vibrating the sieves 1a, 1b and 1c at an optimum frequency to eliminate or reduce the clogging of the powder. Therefore, it is not necessary to provide a brush for preventing clogging as in the prior art, and there is no possibility of contamination due to these wears. Furthermore, a large-scale device like a conventional blower is not necessary. In the above embodiment, three stages of sieves are provided. However, if there is at least one sieve, the sieve is vibrated at an optimum frequency to eliminate or reduce clogging of the powder, The effect of this embodiment that the classification efficiency and the processing amount can be improved.

  In this embodiment, since the frequency of the drive signal is feedback-controlled, even when there is a change in the high speed condition of the mesh screen, the weight of the classification, the mesh of the sieve mesh, etc., the optimum screening is automatically performed. It can be performed.

  In this embodiment, the actuator drive signal is switched from the first mode to the third mode, so that one actuator 2 supplies a drive signal having an optimal frequency to the plurality of sieves 1a, 1b, and 1c. can do. In the above-described embodiment, the three-stage sieve is provided. However, if at least two-stage sieves are used, an effect that an optimum drive signal can be supplied to a plurality of sieves by one actuator 2 is provided. Can play.

  The present invention is not limited to the above-described embodiment, and various design changes can be implemented. Specifically, in the above-described embodiment, one actuator 2 is shared by the plurality of sieves 1a, 1b, and 1c. However, the actuator 2 is provided for each sieve 1a, 1b, and 1c. May be. In this case, the function generator 7 does not need to switch the frequency of the drive signal as shown in FIG. 2, and a different optimum drive signal can be supplied to the actuator 2 provided for each of the sieves 1a, 1b, and 1c. That's fine.

  In the above embodiment, the frequency of the drive signal of the actuator 2 is switched to a frequency at which the classification efficiency of each of the sieves 1a, 1b, and 1c is maximized every predetermined time. There is no need to switch to a frequency that maximizes the classification efficiency of the sieve. In the present invention, if the actuator 2 is driven so that the classification efficiency of any one sieve becomes the maximum at a predetermined time, the clogging of the powder is eliminated or reduced, and the classification efficiency of the powder is improved. The effect of this invention that it can be made can be show | played. Alternatively, the entire sieves 1a, 1b, and 1c may be regarded as one sieve, and the feedback control of the drive signal may be performed so that the classification efficiency is maximized.

DESCRIPTION OF SYMBOLS 1 Net sieve 1a, 1b, 1c Sieve 1d Sieve holder 2 Actuator 3 Coupling material 4 Amplifier 5 Operation part 6 Display part 7 Function generator 8 Control part 9 Sensor

Claims (8)

A mesh screen provided with at least one sieve for sieving the powder;
An actuator for applying vibration to the mesh screen;
A sensor for acquiring information on the classification efficiency of the sieve;
A powder sieving apparatus comprising a control unit that generates a drive signal for driving the actuator based on information on the classification efficiency acquired by the sensor.   The powder sieving apparatus according to claim 1, wherein the control unit controls a frequency of a drive signal for driving the actuator based on information on the classification efficiency acquired by the sensor. The mesh screen includes a first screen and a second screen,
The sensor includes a first sensor that acquires information on the classification efficiency of the first sieve, and a second sensor that acquires information on the classification efficiency of the second sieve,
The actuator is provided in common for the first sieve and the second sieve,
The control unit is configured to generate a drive signal for driving the actuator based on information related to the classification efficiency acquired by the first sensor, and information related to the classification efficiency acquired by the second sensor. And a second mode for generating a drive signal for driving the actuator,
The powder sieving apparatus according to claim 1 or 2, wherein the first mode and the second mode are switched at a predetermined time.   The powder sieving apparatus according to any one of claims 1 to 3, wherein the frequency of the driving signal is 10Hz to 20kHz. For a mesh sieve provided with at least one sieve for sieving powder, obtain information on the classification efficiency of the sieve,
Based on the acquired information on the classification efficiency, a drive signal for driving an actuator that vibrates the sieve is generated, the actuator is driven by the drive signal to vibrate the sieve, and the powder is sieved Body sieving method.   The powder sieving method according to claim 5, wherein the frequency of a drive signal for driving the actuator is controlled based on the acquired information on the classification efficiency. The mesh screen includes a first screen and a second screen,
The actuator is provided in common for the first sieve and the second sieve,
Obtain information on the classification efficiency of the first sieve,
Obtain information on the classification efficiency of the second sieve,
Based on information on the classification efficiency of the first sieve, a first mode for generating a drive signal for driving the actuator, and on the basis of information on the classification efficiency of the second sieve, a drive signal for driving the actuator is generated. The powder sieving method according to claim 5 or 6, wherein the second mode is switched at a predetermined time.   The powder sieving method according to any one of claims 5 to 7, wherein the frequency of the drive signal is 10Hz to 20kHz.

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