JP2005177531A - Classifier screen automatic cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically perform dissolution of clogging when a classifying screen forms a curved surface or even when contour of the screen forms a non-circular flat surface. <P>SOLUTION: The classifier screen automatic cleaning device is constituted so as to include a nozzle arm 10 provided with an air jet nozzle 11 and turning around a horizontal axis; a multi-axis robot arm provided with a θ axis arm 13 provided with the nozzle arm 10 and turning around a vertical axis and a Y axis arm 5 for horizontally moving the θ axis arm 13; a cleaning robot box 2 for supporting the multi-axis robot arm and moving it in a horizontal direction and a vertical direction; and a control means for scanning the whole surface of the classifying screen by the air jet nozzle 11 while retaining a distance of the air jet nozzle tip end from the classifying screen in a predetermined range by controlling action of the robot arm and the cleaning robot box 2. The powder and granular material is classified to a plurality of particle diameters and the classifying screen is automatically cleaned. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a powder classifier, and more particularly, to a classifier screen automatic cleaning device suitable for removing fine powder adhering to a screen.

  An example of a classifier structure having a screen cleaning device according to the prior art is shown in FIG. This classifier has a granular material inlet 21, a granular material outlet 22, an intermediate mass outlet 23, and a large mass outlet 24 formed integrally with the classifier casing 38. The granular material inlet 21 is an upper part. The powder outlet 22 on the upstream side via the expansion joint 30 is connected to the respective fixed devices on the downstream side via the lower expansion joint 31. The entire load of the classifier casing 38 is supported by the fixed base 29 via the spring 28. Further, an inclined screen and a vibration motor 27 are mounted in the classifier casing 38, and the whole is vibrated at a vibration acceleration of 4 to 5G to classify powder particles.

  In the case of this machine, since not only foreign substances and large lumps are removed, but also intermediate lumps are recirculated to the pulverizer, a three-stage screen configuration is adopted. The model is an inclined vibration sieve suitable for large-capacity processing. First, a large mass to be removed from the system is removed by the upper screen 25 from the granular material introduced from the granular material inlet 21, and then an intermediate mass is removed by the middle screen 26. What finally passes through the lower screen 18 is discharged as a product from the granular material outlet 22. The sieved granular material of the middle screen 26 and the lower screen 18 is returned again to the pulverizer and mixed into the raw material.

  As a vibration source, a dual vibration motor 27 that rotates an eccentric weight is provided. In this type of sieve, the thickness of the solid layer on the screen is thin, and the separation efficiency in each screen is increased. Therefore, the separation efficiency is high even if it is relatively compact, and is suitable for large-capacity processing.

  As time elapses after classification starts, fine powder begins to stick to the screen. In the case of this machine, when the amount of fine powder sticking to the screen increases, the lower and middle stages with small openings become obstructive. . For this reason, a cleaning device capable of changing the amplitude of the screen at any time is provided in the lower and middle stages. This is a mechanism in which the screen is stretched during normal operation, loosened during cleaning, and the amplitude is increased by resonating with the vibration of the machine to drop the deposits. For this reason, a short stroke air cylinder 32 that can pull and loosen the screen is connected to the lower screen 18 and the middle screen 26.

  In order to reduce the amount of fine powder attached, a harp screen 36 that has a line only in the direction parallel to the particle flow direction 37 is adopted, or a urethane rubber screen wire 35 is adopted as the screen material. In addition, various measures have been taken, such as installing on the screen a tapping ball 34 that jumps with the vibration of the machine and knocks off the fine powder adhering to the screen.

  Patent Document 1 describes an apparatus for cleaning a screen by jetting air. In this device, the granular material is introduced into the casing from the granular material introduction port, and moves in the horizontal direction while maintaining the fluidized bed state in the granular material on the plane of an endless track that rotates around the horizontal axis. The particle and the particle introduction port and the rotating endless track screen are sandwiched between the particle extraction port and the opposite particle extraction port. This endless track screen has pores through which powder particles cannot pass but fluidized air passes. A suction mechanism is connected to the upper part of the casing. Air in the casing is sucked by the suction mechanism to generate an updraft in the casing, and fine powder in the granular material is floated and removed upward. At this time, clogging of fine powder occurs on the screen with an endless track, and in order to blow it off with air, an air injection nozzle is provided in the lower part of the rotating screen that is not in contact with the granular material. ing.

  In Patent Document 2, a powder fluid to be classified is introduced from one end of a cylindrical mesh separation / classification screen arranged with the axis horizontal, and the inside of the cylindrical mesh separation / classification screen is axially directed. And an apparatus for separating and classifying the screen into those that pass through the screen mesh and those that do not. In this example, a hollow rotating shaft that passes through the axis of the cylindrical mesh separation and classification screen is provided, and a hollow stirring arm that is coupled to the rotating shaft and extends in the axial direction close to the screen surface is provided. And a plurality of apertures are provided in the outer peripheral surfaces of the hollow rotating shaft and the hollow stirring arm so as to eject compressed air. The clogging of the screen mesh is eliminated by the jet of compressed air.

  Further, in Patent Document 3, powder to be classified is sprayed from below a circular plane classification screen, and the powder that has passed through the classification screen is recovered from above the classification screen, and the powder that has not passed through the classification screen. An apparatus is disclosed for recovering the gas under the classification screen. In this example, a screen airbrush that blows high-pressure air toward the classification screen is provided on the upper side of the classification screen to eliminate clogging of the screen mesh.

JP-A-64-85177 JP-A-9-85177 JP-A-8-126848

  However, in the case of each of the above-described apparatuses, there is a problem in processing a granular material such as coal containing moisture and having high adhesion.

  First, in the case of the classifier shown in FIG. 5, the mechanical vibration acceleration has a performance of 4 to 5 G. This is a sufficient force for classifying powder particles flowing on the screen, but it adheres to the screen line. It cannot be enough to break down the fine powder. This is the same whether the screen line amplitude is increased or the screen is struck with a tapping ball. Even if a harp screen starts to adhere, it quickly closes. These function well in the case of dry particles, but continuous operation is almost impossible in the case of coal containing moisture and strong viscosity.

  Next, in the case of the apparatus described in Patent Document 1, basically, a dry granular material that is fluidized with air is targeted. Therefore, when used for classification of a granular material containing moisture, the screen can be used for a short time. With the air dynamic pressure that is clogged with, and that blows off the dried granular material, there is a problem that the dynamic pressure is insufficient to remove fine powder fixed with moisture. Furthermore, the thing of patent document 1 rotates a screen in an endless track shape, moves to the position which opposes the fixed air injection nozzle, and eliminates clogging, and a large curved screen and external shape are not circular. It is difficult to rotate a large flat screen and move it to a position facing the air injection nozzle whose position is fixed.

  In the case of the devices described in Patent Documents 2 to 3, since the target screen is a cylindrical surface or a circular plane, it is difficult to apply when the screen is a curved surface or the outer shape is a plane that is not circular.

  SUMMARY OF THE INVENTION An object of the present invention is to automatically eliminate clogging even when the classification screen has a curved surface or when the screen has a non-circular flat surface.

First, the adhesion and the technical basis of the present invention will be described with reference to so-called pulverized coal obtained by pulverizing coal.
(1) Structure of adhesion The adhesion of powder depends on the substance contained in the powder and the particle diameter. For example, clay substances (kaolinite, mascobite, etc.) contained in coal have a very fine particle size (submicron order), and thus have high adhesion. Further, as a characteristic of clay substances, when water coexists, viscosity is generated and adhesion is greatly increased.
(2) Moisture and amount of adhesion FIG. 10 shows an example of the test result of the relationship between the total moisture value (%) in coal and the amount of adhesion to the screen wire. As shown in FIG. 10, the adhesion amount increases rapidly from the vicinity where the total moisture exceeds 10%, and the clay viscosity due to the coexistence of moisture appears in this vicinity.
(3) Relationship between dynamic pressure during air injection and deposit removal rate The adhering force of the dried granular material is mainly an electric attraction force, which is much weaker than the clay viscosity described above. In particular, the clay is solidified when adhering with moisture and then dried a little, so that the strength of the adhering substance is further increased. To remove this by air injection, much higher dynamic pressure air is required compared to removing dry powder. FIG. 11 shows an example of the test results of the dynamic pressure of cleaning air and the removal rate of attached coal.

As can be seen from FIG. 11, when the total moisture is less than 10%, even air with a low dynamic pressure of about 5 kPa shows a removal rate of 70% or more, but when the total moisture increases to 12 to 18%, the air dynamic pressure becomes 10 kPa. The removal rate finally reaches 70% or more from the vicinity beyond. That is, it is understood that an air dynamic pressure of at least 10 kPa or more is required to remove the coal powder containing such clay and having a moisture content of 12 to 18%.
(4) Classifier operating conditions and robot arm protection The robot arm is composed of a combination of very precise mechanical parts. If dust enters this area, the operation will become unstable and stop the worst. In addition, if the granular material is combustible, there is an electrical component inside the robot arm, so it is necessary to consider explosion protection.

  The present invention has been made on the basis of the above-mentioned knowledge, and the above-mentioned problem is an apparatus for automatically cleaning a classification screen for classifying a powder fluid into a plurality of particle diameters, and includes an air ejection nozzle that ejects compressed air. A multi-axis robot arm provided; advance / retreat means for moving the robot arm back and forth in the flow path of the powder fluid passing through the classification screen; and controlling the operation of the robot arm to move the tip of the air ejection nozzle from the classification screen. This is achieved by an automatic classification screen cleaning device having control means for scanning the entire surface of the classification screen by the air ejection nozzle while maintaining the distance within a predetermined range.

  The dynamic pressure when the compressed air ejected from the air ejection nozzle hits the classification screen is desirably 10 kPa or more. When the dynamic pressure when the compressed air hits the classification screen is 10 kPa or more, it becomes possible to remove the coal powder having a total water content of 12 to 18%.

  Preferably, the robot arm includes a robot arm compressed air supply means for supplying compressed air into the robot arm. By blowing high-pressure sealing air into the robot arm and keeping the inside at a positive pressure to prevent the robot arm from entering dust, the life of the equipment is extended and the operation safety is maintained.

  It is important to temporarily stop the supply of the granular material to the classifier while the cleaning device is in use in order to make the cleaning device perform sufficiently. In the use of the automatic classification screen cleaning device according to the present invention, after temporarily stopping the supply of powder to the classifier, the robot arm equipped with the air ejection nozzle is placed near the classification screen, that is, the powder fluid to be classified. The cleaning of the classification screen is started and the cleaning of the classification screen is completed.After the cleaning of the classification screen is finished, the robot arm is withdrawn from the flow path of the powder fluid to be classified, and then the granular material is supplied to the classifier. It is important to resume.

  If air is sprayed onto the classification screen while supplying the particles to the classifier, the flow of the particles itself is hindered and the operation of the robot arm is also hindered, so it must be stopped. By incorporating this into the operation program of the cleaning device and setting it as the starting condition of the cleaning device, stable operation is possible.

  In order to scan the entire classification screen with the air ejection nozzle, in other words, various devices are required to move the robot arm along the classification screen surface. In other words, the screen is rarely a simple plane and is often a curved surface, and the screen outline is not always a simple square or circle. Furthermore, when the classification screen is enlarged, a support for supporting the classification screen is provided on either side of the classification screen. Therefore, when air is ejected from the support side that supports the classification screen, it is necessary to overcome this. In order to clean the vicinity of the support, it is necessary to change the direction of the air ejection nozzle between the front side and the opposite side of the air ejection nozzle.

  In order to cope with such a condition, the robot arm is multi-axial, that is, has a multi-axis freedom. In addition, it is advantageous to operate the robot operation program on a computer that can handle various programs, that is, a so-called general-purpose computer, so that a plurality of programs can be created and switched according to the situation. Become.

  According to the present invention, it is possible to realize an automatic classification screen cleaning device that can automatically eliminate clogging even when the classification screen has a curved surface, or even when the outer shape of the screen is a flat surface. become.

(Example 1)
Hereinafter, an automatic classification screen cleaning apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. In the following description, the direction orthogonal to the paper surface of FIG. 1 is referred to as the X axis, the horizontal direction of the paper surface is referred to as the Y axis, and the vertical direction of the paper surface is referred to as the Z axis.

  FIG. 1 is a side view showing the overall structure of a classification screen automatic cleaning apparatus according to the present embodiment, and FIG. 2 is a plan view taken along line AA in FIG. The classifying screen automatic cleaning apparatus shown in the figure includes an X-axis linear guide (travel rail) 1 installed on the floor, a rack 4 disposed on the floor in parallel with the X-axis linear guide 1, and the X-axis. A cleaning robot housing 2 that travels on the linear guide 1, an X-axis motor 3 that is mounted on the cleaning robot housing 2 and coupled to a drive shaft engages with the rack 4, and is supported on the upper portion of the cleaning robot housing 2. The robot arm, the Z-axis motor 8 housed in the cleaning robot housing 2, the Z-axis ball screw 9 housed in the cleaning robot housing 2 and driven by the Z-axis motor 8, and the side surface of the cleaning robot housing 2 A cable bearer 17a for connecting one end of the robot arm, a control panel (not shown) which is built in the cleaning robot casing 2 and controls the operation of the entire apparatus, and the cleaning robot casing Is configured to include arranged separately, the relay box 15 connected with the cleaning robot housing 2 and the cable carrier 17b, a and.

  The robot arm is disposed along the longitudinal direction of the Y-axis arm 5, the Y-axis arm 5 supported on the upper part of the cleaning robot housing 2, the Y-axis motor 6 fixed to one end of the Y-axis arm 5, and the Y-axis arm 5. A Y-axis ball screw 7 rotated by the Y-axis motor 6, a θ-axis arm 13 attached to the other end of the Y-axis arm 5 so as to be rotatable about a straight line (θ-axis) parallel to the Z-axis, A θ-axis motor 12 fixed to the other end of the Y-axis arm 5 and rotating the θ-axis arm 13 about the θ-axis, and an XY plane orthogonal to the longitudinal direction of the θ-axis arm 13 at the tip of the θ-axis arm 13 A nozzle arm 10 pivotally mounted with a straight line (A axis) parallel to the axis as a rotation axis, and an A axis motor 14 fixed to the θ axis arm 13 and rotating the nozzle arm 10 about the A axis. And an air ejection nozzle 11 fixed to the tip of the nozzle arm 10 And.

  The Y-axis arm 5, the θ-axis arm 13, and the nozzle arm 10 are all configured in a hollow structure, and mechanical parts such as the Y-axis ball screw 7, motors, and electric wires are accommodated in the hollow structure, and in the hollow structure. Compressed air is injected. Also, the connecting portions of the Y-axis arm 5 and the θ-axis arm 13 and the θ-axis arm 13 and the nozzle arm 10 are also pressurized inside with compressed air so that dust does not enter the connecting portion from the outside.

  The Y-axis arm 5 expands and contracts in accordance with the rotation of the Y-axis ball screw 7, and together with the Y-axis motor 6 and the Y-axis ball screw 7, when cleaning the classification screen, the robot arm is placed in a casing in which the classification screen is installed. That is, it is an advancing / retreating means for advancing / retreating with respect to the flow path of the powder fluid.

  The cleaning robot housing 2 is connected to the control panel, the X-axis motor 3, the Z-axis motor 8, the Z-axis ball screw 9, and the chassis portion on which the wheels that engage with the X-axis linear guide 1 are mounted. The Y-axis arm support is supported by the Z-axis ball screw 9 and moves up and down according to the rotation of the Z-axis ball screw 9. The Y-axis arm 5 is supported by the Y-axis arm support.

  An external compressed air pipe, a power cable, and a control cable are connected to the relay box 15. From the relay box 15 to the cleaning robot casing 2, a high-pressure air hose for cleaning air and an air tube for control air for sealing, A power cable and a control cable are provided in the cable bear 17b. From the cleaning robot housing 2 to the robot arm (specifically, one end of the Y-axis arm 5), the high pressure air hose for cleaning air, the air tube for control air for sealing, the power cable, and the control cable are the cable bear 17a. Decorated in.

  The control panel includes a control computer, and controls the operation of each motor according to a control program and signals from various sensors, opens / closes an automatic opening / closing door of a casing equipped with a classification screen, and illustrates a compressed air system piping. There is no valve open / close control. The operation of the cleaning device is computerized based on the shape and size of the classification screen, and this computer program is installed in the control computer built in the control panel.

  A plurality of types of computer programs for controlling the operation of the cleaning device are prepared, including one spare, and can be freely selected with one button. In this embodiment, a. Full standard speed cleaning, b. Full high-speed cleaning, c. Classifier side + cleaning around pipe support, d. Screen single-sided cleaning, e. There are five types of spare. Thus, by preparing a plurality of types of computer programs for controlling the operation of the cleaning device, it is possible to flexibly cope with the cleaning device in actual operation.

  This device translates in the X, Y and Z basic three axes, and around the two axes of the θ axis and A axis for moving the air ejection nozzle 11 at the tip of the robot arm to an arbitrary position. There are a total of five degrees of freedom of rotation (rotation), and the operation related to each axis is driven by a dedicated servo motor. In some cases, a proximity sensor may be provided at the tip of the air ejection nozzle 11, and control in the Z-axis direction may be performed based on a signal from the proximity sensor without being converted into a computer program.

  The cleaning robot housing 2 has two X-axis linear guides 1 laid on a plane and meshes with a rack 4 and a pinion driven by an X-axis motor 3 in the X-axis direction (perpendicular to the plane of FIG. 1). The end of the Y-axis arm 5 on the cleaning robot housing 2 on the θ-axis arm 13 side is rotated by the Y-axis motor 6 and the Y-axis ball screw 7 in the Y-axis direction (left and right direction on the paper surface). Move forward and backward. Further, the rotation of the Z-axis motor 8 and the Z-axis ball screw 9 in the cleaning robot casing 2 causes the Y-axis arm support and the entire Y-axis arm 5 of the cleaning robot casing 2 to move up and down.

  The entire θ-axis arm 13 is driven by the rotation of the θ-axis motor 12 and rotates left and right within a range of about 270 degrees. The nozzle arm 10 is also driven by the rotation of the A-axis motor 14 and moves up and down (rotates) about the A-axis within a range of about 260 degrees.

  Normally, if there are three axes, a three-dimensional operation is theoretically possible. However, according to this embodiment, the direction and position of the tip of the nozzle 11 can be determined regardless of the complicated shape and arrangement of the screen. It becomes possible to move according to the shape and arrangement, and cleaning according to the shape and arrangement of the classification screen can be performed.

  Next, FIG. 3 shows an overall arrangement of the classification screen automatic cleaning device (hereinafter referred to as a cleaning device) having the above-described configuration, FIG. 4 is a plan view taken along line BB in FIG. 3, and FIG. C side arrow side views are shown respectively. The cleaning compressed air used in this apparatus is exchanged with the external compressed air pipe 16 in the relay box 15. Here, the external compressed air pipe 16 is connected to the cleaning air and the control air for sealing separately. Has been. From here, the cleaning air is connected to the air jet nozzle 11 at the tip by a high-pressure air hose in the cable bearers 17a and 17b.

  On the other hand, the control air for sealing is sent to each part through the air tubes which are the robot arm compressed air supply means in the cable bearers 17a and 17b, and the inside of the robot arm (the Y-axis arm 5, the θ-axis arm 13 and the nozzle arm 10). Used to pressurize each interior).

  The pressure of the compressed air is always automatically monitored by the control panel, and the cleaning device is automatically stopped when the pressure becomes below a set value.

  In this embodiment, a case where the present invention is applied to the classifier shown in FIG. 5 will be described. However, a cleaning device is disposed on the outlet side (lower side) of the lower screen 18 because of the classification screen arrangement space. Also, for the maintenance work of the cleaning device main body, the cleaning device main body normally stands by outside the classifier lower casing 20 that completely surrounds the classifier, and only when cleaning is required. The automatic opening / closing door 19 provided in the machine lower casing 20 is opened to enter the interior, cleaned, and when finished, the classifier lower casing 20 is moved out and the automatic opening / closing door 19 is closed again. The opening / closing control of the automatic door 19 is associated with a computer program for controlling the operation of the cleaning device, and is controlled by this computer program.

  The compressed air pressure for cleaning is preferably a high pressure within a practical range. In this embodiment, 1.5 MPa is adopted. The nozzle diameter of the air ejection nozzle 11 and the distance between the tip of the air ejection nozzle 11 and the classification screen during cleaning were set so that the dynamic pressure applied to the classification screen was 10 kPa or more.

The operation procedure of the apparatus having the above configuration is as follows. An example of full standard speed cleaning is shown. The following operations are computerized and stored in the control computer.
a. Confirming stoppage of powder fluid supply of the classifier equipped with a classification screen to be cleaned,
b. Instructions for opening the doors of casings with classification screens and confirmation of completion,
c. Start supplying sealing air to the robot arm.
d. Cleaning position in the casing of the robot arm, that is, entering the powder fluid flow path,
e. Air jet nozzle movement to the cleaning start point,
f. Confirmation of the arrival of the air ejection nozzle to the cleaning start point,
g. Start supplying compressed air to the air ejection nozzle,
h. From the cleaning start point to the cleaning end point, the entire screen of the classification screen is scanned by the air ejection nozzle while keeping the distance between the air ejection nozzle and the classification screen within a predetermined range.
i. Confirmation of the arrival of the air ejection nozzle at the end of cleaning,
j. Stop supplying compressed air to the air ejection nozzle,
k. Exiting the robot arm casing,
l. Casing door closing instruction and confirmation of completion,
m. Stop supplying air for sealing to the robot arm,
n. Signal output for cleaning completion.

  FIG. 6 shows a procedure for cleaning the lower screen 18. When all the starting conditions are met and it is confirmed that the automatic opening / closing door 19 is opened, the robot arm starts to move under the control of the control panel, enters the classifier lower casing 20 from the automatic opening / closing door 19 and moves to the lower screen. Scanning by the 18 air ejection nozzles 11, that is, cleaning is started in the order of the arrows from a preset cleaning start point a. The lower screen 18 is divided into left and right two by the central partition plate 39, but when one side is completed, it moves to the opposite side, performs cleaning in the same way, reaches the cleaning end point B, scans the entire classification screen, that is, cleaning When is completed, the route returns to the standby position via the approach route.

  In the present embodiment, the classifier stops accepting powder particles during the cleaning of the classification screen, but the vibration motor of the classifier continues to operate during the cleaning of the classification screen to promote the removal of deposits. In the above procedure, when the cleaning device control panel is instructed to start cleaning, the cleaning device control panel starts the work from the confirmation of the acceptance stop of the granular material. A function for instructing may be provided, and the acceptance of the granular material may be stopped at a predetermined time interval to clean the classification screen, and the acceptance of the granular material may be resumed after the cleaning is completed.

According to the present embodiment, not only a fine air jet nozzle movement that can be applied to a classifier having a complicated screen structure is realized, but also air injection by a high dynamic pressure of 10 kPa or more and vibration acceleration of 4 to 5 G are achieved. Due to the combined synergistic removal effect, there is an effect that deposits can be removed at a high removal rate throughout the classification screen.
(Example 2)
FIG. 7 is a side view showing the structure of a classification screen automatic cleaning apparatus according to Embodiment 2 of the present invention. FIG. 8 is a plan view of FIG. The present embodiment is an automatic classifying screen cleaning device that can be applied when the classifier screen arrangement is a simple horizontal plane arrangement. In this case, the classification screen can be cleaned only by moving the air ejection nozzle 11 along the X and Y axes. The Z axis motor 8, the Z axis ball screw 9, the θ axis arm 13 and the θ axis motor of the first embodiment are used. 12, the nozzle arm 10 and the A-axis motor 14 are not provided, and the entire cleaning device is configured to have a degree of freedom for the X and Y axes. The air ejection nozzle 11 is fixed to the Y-axis arm 5 in a fixed direction close to a right angle with respect to the classification screen. Others are the same as those of the first embodiment shown in FIGS.

  According to the present embodiment, the degree of freedom of operation of the robot arm is less than that of the first embodiment, but the whole can be made compact.

  Although the number of air ejection nozzles 11 is one in both the first and second embodiments, a plurality of nozzles can be installed. In that case, the scanning pitch may be changed. This is determined by the amount of air that can be used, the nature of the adhering fine powder, the operation pattern of the classifier, and the like.

It is a block diagram which shows Example 1 of the screen automatic cleaning apparatus which becomes this invention. It is an AA arrow directional plan view of FIG. It is a side view which shows notionally the operation state of the classification screen automatic cleaning apparatus shown in FIG. FIG. 4 is a plan view taken along line B-B in FIG. 3. FIG. 5 is a side view taken along line CC in FIG. 4. It is a top view which shows the example of the locus | trajectory of the air ejection nozzle at the time of cleaning of the classification screen by the Example shown in FIG. It is a side view which shows the classification screen automatic cleaning apparatus which concerns on Example 2 of this invention. It is a top view of the classification screen automatic cleaning apparatus shown in FIG. It is sectional drawing which shows the example of a prior art. It is a graph which shows the relationship between the total moisture in coal, and the adhesion amount to a screen. It is a graph which shows the relationship between the dynamic pressure of cleaning air, and the adhesion coal removal rate.

Explanation of symbols

1 X-axis linear guide 2 Cleaning robot housing 3 X-axis motor 4 Rack 5 Y-axis arm 6 Y-axis motor 7 Y-axis ball screw 8 Z-axis motor 9 Z-axis ball screw 10 Nozzle arm 11 Air ejection nozzle 12 θ-axis motor 13 θ-axis Arm 14 A-axis motor 15 Relay box 16 External compressed air piping 17a, 17b Cable carrier 18 Lower screen 19 Automatic open / close door 20 Classifier lower casing 38 Classifier casing 39 Central divider

Claims (3)

An apparatus for automatically cleaning a classification screen for classifying a powder fluid into a plurality of particle sizes, the multi-axis robot arm having an air ejection nozzle for ejecting compressed air, and the multi-axis robot arm passing through the classification screen Advancing / retreating means for advancing and retreating to the flow path of the powder fluid, and controlling the operation of the multi-axis robot arm to maintain the distance from the classification screen at the tip of the air ejection nozzle within a predetermined range, while the air ejection nozzle A classifying screen automatic cleaning device comprising a control means for scanning the entire classifying screen. 2. The automatic classification screen cleaning apparatus according to claim 1, wherein a dynamic pressure when compressed air ejected from the air ejection nozzle hits the classification screen is 10 kPa or more. 3. The automatic classification screen cleaning apparatus according to claim 1, further comprising a robot arm compressed air supply means for supplying compressed air into the robot arm.

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