JP2011219559A - Laser machining device and laser machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser machining device which, when a refractory brick furnace wall is shaped and cut, can prevent the imposition of damage on another furnace wall.SOLUTION: The laser machining device includes: a laser irradiating part to irradiate a refractory brick furnace wall with laser light; a light emission intensity measuring part to measure the light emission intensity at a laser light irradiation point; and a control part to control the laser irradiating part according to the laser cutting condition for the refractory brick furnace wall based on the measurement result. The control part has a laser information storing part to store the laser cutting condition for the thickness of the refractory brick; a machining condition determination processing part to pre-irradiate laser light on the refractory brick furnace wall at an optional position on a cutting line of the refractory brick furnace wall before shaping and cutting the circumference of a broken bore part, to estimate the remaining thickness of the refractory brick, and to determine the laser cutting condition at shaping and cutting of the refractory brick furnace wall; and a drive control part to control the output intensity of the laser light of the laser irradiating part and the moving speed of the laser irradiating part based on the determined laser cutting condition.

Description

The present invention relates to a laser processing apparatus and a laser processing method for high-temperature refractory bricks, and more particularly to a technique for repairing a structure made of refractory bricks in a high-temperature environment.
About.

  Although refractory bricks are used in various structures such as furnaces, processing of refractory bricks may be required in a high temperature environment as the refractory deteriorates. As an example, there is a process for hot repairing a wall surface of a coke oven for carbonizing coal.

  The coke oven is divided into a combustion chamber for heating the furnace and a carbonization chamber for generating coke, and refractory bricks are used for the wall surfaces. Over many years of use of the furnace, refractory bricks are subject to surface damage and cracks, and finally to piercing from the carbonization chamber to the combustion chamber. In particular, when a puncture occurs, the inserted coal spills into the combustion chamber and closes the combustion gas supply port, or coke gas flows from the carbonization chamber into the combustion chamber, causing incomplete combustion and generating black smoke. Cause it.

  Since the coefficient of thermal expansion of the refractory brick on the furnace wall changes abruptly around 600 ° C., cooling the furnace below this temperature may damage the entire furnace wall due to thermal shock. For this reason, it is desirable to repair the furnace wall in a high temperature environment from 700 ° C. to 1000 ° C. which is the operation temperature. As a method of processing bricks at a high temperature, a laser method is attracting attention. Laser machining has the advantage that it can be safely shaped without affecting the strength of the normal furnace wall around the broken hole because mechanical stress is not generated compared to mechanical machining such as cutting. .

  Here, the coke oven extrudes coke in one direction after the completion of the carbonization of the coke, which is a raw material, so that selling stress is applied to the furnace wall. For this reason, the fire-resistant brick wall surface easily cracks along the joint with weak strength. At this time, since the refractory bricks are alternately stacked, for example, as shown in FIG. 10, the crack is likely to enter a position about ½ of the width (x direction) of the refractory brick 10. When the cracked state continues for a long time in this way, the crack progresses to the depth, the site where the strength is weakened is destroyed, and a hole (broken hole H) is generated in the refractory brick furnace wall.

  The inventors of the present application conducted an experiment to generate such a broken hole H in a simulated manner. As a result, when the hole H is pushed from the carbonization chamber side, how to remove the dowels that are convex portions formed on the contact surfaces of the refractory bricks 10 is the vertical direction (z direction) where the load is applied, It has been found that the shape of the hole H is different in the left and right direction (x direction) which is not loaded and is relatively restrained.

  In other words, since no load is applied in the left-right direction of the broken hole H, deformation that spreads to the left and right is possible, and there is no dowel on one side of the refractory brick 10 that has cracked at about a half position. Therefore, since there is little catching with the other refractory bricks 10, the dowels can be removed. For this reason, for example, as shown in FIG. 11, the refractory brick 10 is neatly destroyed along the joint. On the other hand, the vertical direction of the broken hole is not easily deformed because the restraint due to the load acts strongly. In addition, since there are dowels on both sides, when the dowels come out, the surroundings (upper and lower connecting parts) break together and break. For this reason, for example, as shown in FIG. 12, the combustion chamber side of the refractory brick 10 has a tapered cross section (also referred to as a reference numeral 10a, a tapered portion).

  The refractory brick furnace wall in which such a pierced hole H is generated is repaired by, for example, fitting the refractory brick into the pierced hole portion and spray-fixing the periphery thereof. At this time, by widening the installation range of the fire-resistant bricks for repair, the installation can be made easy and stable. For example, as shown in FIG. 13, Patent Document 1 discloses a method in which a firebrick 10 around a hole H is shaped and cut, and then a firebrick 11 is fitted and sprayed and fixed.

JP 2008-143966 A

  Here, laser shaping cutting around the hole H is performed along cutting lines represented by lines L1 to L4 in FIG. 10 in consideration of shortening of the cutting time. Here, the upper and lower two cutting lines L1 and L3 cut the tapered portion 10a shown in FIG. 12, and the refractory brick 10 that is thinner than the original thickness is cut. However, since the back surface (combustion chamber side) of the refractory brick furnace wall is broken in a taper shape, the thickness of the cutting position can be recognized from the surface (carbonization chamber side) of the refractory brick furnace wall irradiated with laser light. Can not.

  Considering that the cutting lines L2 and L4 are also cracked, it is considered that the cutting of the refractory brick 10 at such a position can be performed more easily than the refractory brick 10 in which no crack is generated. That is, it can be said that the effective thickness of the refractory brick 10 in laser cutting is smaller than the apparent thickness of the refractory brick 10. However, since the effective thickness due to the introduction of such a crack is unknown, it is impossible to know how easily the firebrick 10 is cut.

  On the other hand, as shown in FIG. 14, the coke oven has a structure in which carbonization chambers and combustion chambers are alternately arranged. When the periphery of the broken hole H is shaped and cut, a furnace wall (for example, in FIG. 14) In the back of the furnace wall 1B), there is a normal furnace wall (1C) in which no hole H is generated. When shaping and cutting, if the laser beam is irradiated to the furnace wall with too much output intensity, it can penetrate the furnace wall to be cut, but the excess laser will irradiate the normal furnace wall and give damage become.

  Then, this invention is made | formed in view of the said problem, The place made into the objective of this invention estimates the thickness of the refractory brick in the cutting position which cut | disconnects a refractory brick furnace wall, and is based on an estimation result. It is an object of the present invention to provide a new and improved laser processing apparatus and laser processing method capable of preventing damage to other furnace walls by setting the output intensity of laser light at the time of cutting.

  In order to solve the above-described problems, according to a certain aspect of the present invention, a refractory brick furnace is used for hot repairing a broken hole portion formed in a refractory brick furnace wall that separates a carbonization chamber and a combustion chamber of a coke oven. There is provided a laser processing apparatus that irradiates a wall surface with laser light to shape and cut the periphery of a hole. Such a laser processing apparatus includes a laser irradiation unit that irradiates the surface of the refractory brick furnace wall with laser light, a light emission intensity measurement unit that measures light emission intensity at a laser light irradiation point on the surface of the refractory brick furnace wall, and a measurement of the light emission intensity measurement unit. A control unit that controls the laser irradiation unit according to the laser cutting condition of the refractory brick furnace wall based on the result, and the control unit stores the laser cutting condition with respect to a preset thickness of the refractory brick Before shaping and cutting the periphery of the memory part and the pierced hole part, the surface of the refractory brick furnace wall is preliminarily irradiated with laser light at an arbitrary position on the cutting line for cutting the refractory brick furnace wall, and the remaining thickness of the refractory brick A processing condition determination processing unit that determines a laser cutting condition at the time of shaping and cutting the refractory brick furnace wall with reference to the laser information storage unit based on the estimation result, and a processing condition determination processing unit Based on a more determined laser cutting conditions, and having a drive control unit for controlling the moving speed of the output intensity and the laser irradiation portion of the laser light from the laser irradiation unit.

  The laser information storage unit stores the relationship between the thickness of the refractory brick and the irradiation time of the laser beam until the refractory brick penetrates when the refractory brick is continuously irradiated with the laser beam, and the processing condition determination processing unit May estimate the remaining thickness based on the irradiation time from the start of irradiation of the laser beam to the surface of the refractory brick furnace wall until the refractory brick furnace wall penetrates.

  The laser information storage unit stores the relationship between the thickness of the refractory brick and the number of times the laser pulse is irradiated until the refractory brick penetrates when the refractory brick is irradiated with the laser pulse, and processing condition determination processing The part may estimate the remaining thickness based on the number of times of laser pulse irradiation until the refractory brick furnace wall penetrates.

  The laser cutting condition at the time of shaping and cutting of the refractory brick furnace wall can penetrate the refractory brick furnace wall having the remaining thickness estimated by the processing condition determination processing unit, and is adjacent to the back side of the refractory brick furnace wall. It can be set not to reach the furnace wall surface.

  The processing condition determination processing unit may preliminarily irradiate the laser beam at a plurality of positions on the cutting line to estimate the remaining thickness of the refractory brick.

  Moreover, in order to solve the above-mentioned problem, according to another aspect of the present invention, when repairing the broken hole portion generated in the refractory brick furnace wall that separates the carbonization chamber and the combustion chamber of the coke oven, There is provided a laser processing method in which a laser beam is irradiated on the surface of a refractory brick furnace wall and the periphery of the broken hole portion is shaped and cut by a laser processing apparatus. The laser processing method includes a laser irradiation step of irradiating the surface of the refractory brick furnace wall with a laser beam by the laser irradiation unit, and an emission intensity for measuring the emission intensity at the laser beam irradiation point on the surface of the refractory brick furnace wall by the emission intensity measurement unit. And a control step for controlling the laser irradiation unit according to the laser cutting condition of the refractory brick furnace wall based on the measurement result by the light emission intensity measurement unit, and the control step shapes the periphery of the hole portion Pre-irradiation step of pre-irradiating the surface of the refractory brick furnace wall with laser light at any position on the cutting line for cutting the refractory brick furnace wall before cutting, and laser irradiation of the surface of the refractory brick furnace wall during pre-irradiation A remaining thickness estimation step for estimating the remaining thickness of the refractory brick based on the light emission intensity at the point, and a preset refractory level based on the estimation result. With reference to the laser information storage unit that stores the laser cutting condition for the thickness of the moth, based on the processing condition determination step for determining the laser cutting condition at the time of shaping and cutting the refractory brick furnace wall, and the determined laser cutting condition, And a drive control step for controlling the output intensity of the laser beam of the laser irradiation unit and the moving speed of the laser irradiation unit.

  As described above, according to the present invention, the thickness of the refractory brick at the cutting position for cutting the refractory brick furnace wall is estimated, and the output intensity of the laser beam at the time of cutting is set based on the estimation result. It is possible to provide a laser processing apparatus and a laser processing method capable of preventing the furnace wall from being damaged.

It is explanatory drawing which shows the structure of the laser processing apparatus which concerns on embodiment of this invention. It is a block diagram which shows the function structure of the laser processing apparatus which concerns on the same embodiment. It is a flowchart which shows the laser processing method using the laser processing apparatus concerning the embodiment. It is explanatory drawing which shows a hole and a cutting line when a refractory brick furnace wall is seen from the carbonization chamber side. It is a graph which shows the relationship between the output of a laser beam, and the emitted light intensity from the firebrick surface. It is a graph which shows the relationship between the thickness of a refractory brick, and the irradiation time of the laser beam to penetration. It is a graph which shows the relationship between the frequency | count of irradiation when a laser pulse is irradiated to a firebrick, and the average value of the emitted light intensity of the firebrick surface in an irradiation point. It is a graph which shows the relationship between the frequency | count of irradiation of the laser pulse required in order to penetrate a refractory brick, and brick thickness. It is explanatory drawing which shows the outline of the experiment for determining the suitable laser cutting conditions in laser processing. It is explanatory drawing which shows a broken hole when seeing a refractory brick furnace wall from the carbonization chamber side. FIG. 11 is a partial cross-sectional portion taken along the line II in FIG. 10. FIG. 11 is a partial cross-sectional portion taken along the line II-II in FIG. 10. It is explanatory drawing which shows the repair method of the refractory brick furnace wall which inserts a brick in a broken hole part, and spray-fixes the periphery. It is explanatory drawing which shows the processing operation | work of the coke oven wall by a laser processing apparatus.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Configuration of laser processing apparatus>
First, based on FIG. 1 and FIG. 2, the structure of the laser processing apparatus 100 which concerns on embodiment of this invention is demonstrated. FIG. 1 is an explanatory diagram showing the configuration of the laser processing apparatus 100 according to the present embodiment. FIG. 2 is a block diagram showing a functional configuration of the laser processing apparatus 100 according to the present embodiment.

[Device configuration]
First, based on FIG. 1, the apparatus structure of the laser processing apparatus 100 which concerns on this embodiment is demonstrated. As shown in FIG. 1, the laser processing apparatus 100 according to this embodiment includes a laser irradiation apparatus 110 that irradiates laser light, and a control apparatus 120 that controls the laser processing apparatus 100.

  The laser irradiation device 110 is a device that irradiates a refractory brick furnace wall, which is a workpiece, with laser light, and includes a laser light output unit U0, a laser processing head unit U1, and a processing observation unit U2 in FIG. Consists of.

The laser beam output unit U0 outputs a laser beam to the laser processing head unit U1 via the optical fiber 111 based on an irradiation instruction from the control device 120. The type of laser of the laser irradiation apparatus 110 according to the present embodiment is not particularly limited. For example, a fiber laser, a YAG laser, or a CO ₂ laser can be used. Below, the case where a fiber laser is used is demonstrated.

  The laser processing head unit U1 is a unit that outputs laser light to the refractory brick furnace wall, and includes a collimator head 112, a reflection mirror 113, and a condenser lens 114. The laser beam input from the laser beam output unit U0 via the optical fiber 111 is converted into the parallel beam 5 by the collimator head 112. The parallel beam 5 is reflected by the reflecting mirror 113 and collected by the condenser lens 114, and then passes through the transmission window 115 and the processing nozzle 116 for injecting processing assist air, and the processing position 15 of the high-temperature refractory brick 10. Is irradiated.

  The processing observation unit U2 is a unit for observing the state of laser processing, and includes a light emission intensity measuring device 117, a lens 118, and an optical filter 119. The processing observation unit U2 is provided behind the reflection mirror 113 (on the side opposite to the condenser lens 114 with respect to the reflection mirror 113). The light emission intensity measuring device 117 is a device that measures the light emission intensity at the laser irradiation point from the rear of the laser beam and the same axis. For example, a CCD camera or a photodiode can be used. Hereinafter, a case where a CCD camera is used as the emission intensity measuring device 117 will be described. In this case, the average value of the light emission at the laser irradiation point is preferably used as the light emission intensity for the evaluation of the laser processing state (for example, the progress of the processing).

  The lens 118 is a CCD camera lens. The optical filter 119 is a filter that cuts off the wavelength of the laser used for processing and reduces the luminance of the light emitting point. The optical filter 119 prevents the light of the laser itself used for processing from affecting the measurement when measuring the emission intensity at the laser irradiation point, and saturation of the gain of the CCD camera by the emission luminance. It is provided to prevent The emission intensity measuring device 117 of the processing observation unit U2 is connected to the control device 120 by a cable. As a method of measuring light emission luminance using a CCD camera, a method of setting a threshold value of light emission luminance in advance and integrating only the luminance value of a CCD camera cell having luminance information greater than or equal to the threshold value at the time of measurement, etc. Can be used.

  The laser processing head unit U1 and the processing observation unit U2 of the laser irradiation device 110 are provided with a heat insulating cooling box 105 having a water cooling mechanism (not shown) in order to reduce the influence of thermal radiation of the refractory brick 10 that is at a high temperature. It is preferable to be accommodated in At this time, purge gas is supplied into the adiabatic cooling box 105. The adiabatic cooling box 105 is provided so as to be movable vertically and horizontally by a manipulator (reference numeral 106 in FIG. 14).

  The control device 120 determines the output intensity of the laser light irradiated to the refractory brick 10 based on the input information from the emission intensity measuring device 117 of the processing observation unit U2 of the laser irradiation device 110, and the laser light of the laser irradiation device 110. An irradiation instruction is given to the output unit U0. The control device 120 also controls a moving mechanism that moves the laser irradiation device 110. The functional configuration of the control device 120 will be described later.

[Function configuration]
Next, the functional configuration of the laser processing apparatus 100 according to the present embodiment will be described based on FIG. The laser processing device 100 cuts the refractory brick furnace wall based on the cutting line determined by the cutting position determination device 220. When the broken hole H is detected in the refractory brick furnace wall by the broken hole detection device 210, the cutting position determining device 220 determines a cutting line for shaping and cutting the periphery of the broken hole H in order to repair the broken hole H. And output to the laser processing apparatus 100. As shown in FIG. 2, the laser processing apparatus 100 includes a laser irradiation device 110, a control device 120, and a moving mechanism 130 that moves the laser irradiation device 110.

  The laser irradiation device 110 is a device that irradiates a workpiece with laser light based on an irradiation instruction from the control device 120, and is configured as shown in FIG. The laser irradiation device 110 outputs the light emission intensity at the laser irradiation point to the control device 120 as a value for evaluating the laser processing state by the light emission intensity measuring device 117.

  As shown in FIG. 2, the control device 120 includes a position control unit 121, an irradiation control unit 122, an output intensity determination processing unit 123, and a laser information storage unit 124. The position control unit 121 and the irradiation control unit 122 are drive control units that drive and control the moving mechanism 130 and the laser irradiation apparatus 110. Further, the output intensity determination processing unit 123 is a processing condition determination processing unit that performs preliminary processing before the refractory brick furnace wall is shaped and cut, and determines a cutting condition by a laser at the time of shaping and cutting.

  The position control unit 121 controls the moving mechanism 130 that moves the laser irradiation device 110. The position control unit 121 controls a moving mechanism 130 that moves the laser irradiation device 110 according to the processing position of the workpiece, for example, a manipulator (reference numeral 106 in FIG. 14). Then, the position controller 121 receives the driving information of the moving mechanism 130, recognizes the position of the laser irradiation device 110, and uses it for driving control of the next moving mechanism 130.

  The irradiation control unit 122 instructs the laser irradiation apparatus 110 to irradiate laser light. For example, the irradiation control unit 122 gives an irradiation instruction to the laser irradiation apparatus 110 for performing preliminary irradiation for determining the output intensity of the laser light when processing the refractory brick 10 based on the instruction of the output intensity determination processing unit 123. Do. Further, the irradiation control unit 122 performs laser irradiation so as to output laser light with the output intensity determined by the output intensity determination processing unit 123 according to the processing position (cutting line) of the workpiece determined by the cutting position determination device 220. Instruct the device 110.

  Further, the measurement result (for example, emission intensity at the laser irradiation point) is input to the irradiation control unit 122 from the emission intensity measuring device 117. The irradiation control unit 122 can determine whether or not the refractory brick 10 has penetrated from the measurement result of the light emission intensity measuring device 117, and determine whether or not the refractory brick 10 is processed normally. can do. At the time of preliminary irradiation, the irradiation control unit 122 outputs the input measurement result of the light emission intensity measuring device 117 to the output intensity determination processing unit 123.

  The output intensity determination processing unit 123 performs preliminary processing before shaping and cutting the refractory brick furnace wall, and determines cutting conditions (output intensity and cutting speed) using a laser during shaping cutting. The irradiation intensity determination unit 123 includes an output intensity determination unit 1231, a timer unit 1232, and a count unit 1233.

  The output intensity determination unit 1231 determines the output intensity of the laser beam at the time of shaping and cutting based on the laser processing state of the refractory brick furnace wall by preliminary irradiation. The output intensity determination unit 1231 performs a preliminary process of irradiating a laser until the refractory brick 10 penetrates at an arbitrary position on the cutting line. For example, the output intensity determination unit 1231 acquires the laser irradiation time in the preliminary processing from the timer unit 1232 or acquires the number of laser pulse irradiations in the preliminary processing from the count unit 1233. Then, the output intensity determination unit 1231 refers to a laser information storage unit 124 to be described later, and determines an appropriate laser cutting condition (output intensity and cutting speed) at the time of shaping and cutting based on the acquired value. At this time, the output intensity determination unit 1231 outputs an irradiation instruction for preliminary processing to the irradiation control unit 122 and receives the detection result of the emission intensity measuring device 117 from the irradiation control unit 122.

  The timer unit 1232 starts measuring the elapsed time according to the measurement start instruction from the output intensity determining unit 1231, stops the measurement according to the measurement stop instruction, and notifies the output intensity determining unit 1231 of the measured elapsed time. In this embodiment, in the timer part 1232 preliminary processing, the time from the start of laser irradiation to the refractory brick 10 to the penetration of the refractory brick 10 is measured. Further, the count unit 1233 starts counting the number of times of laser pulse irradiation according to the count start instruction from the output intensity determination unit 1231, stops counting according to the count stop instruction, and notifies the output intensity determination unit 1231 of the count number. In the present embodiment, the number of laser pulses irradiated until the refractory brick 10 penetrates is measured in the preliminary processing of the count unit 1233. The output intensity determination processing unit 123 only needs to include at least one of the timer unit 1232 and the count unit 1233.

  The laser information storage unit 124 stores the relationship between the preliminary irradiation result acquired in advance and the thickness of the refractory brick. For example, the laser information storage unit 124 stores the relationship between the result of preliminary irradiation as shown in FIG. 6 or FIG. 8 described later and the thickness of the refractory brick. FIGS. 6 and 8 are obtained by cutting a refractory brick at a high temperature (1000 ° C.) in the same manner as the cutting of the example under the same laser output, condensing spot diameter, and assist air conditions as in the examples described later. is there. Such information is acquired in advance by an experiment to be described later based on FIG. 9 and stored in the laser information storage unit 124. Such information is referred to by the irradiation control unit 122 and the output intensity determination processing unit 123 to determine whether the laser processing is normally performed and the cutting conditions (output intensity and cutting speed) by the laser at the time of shaping and cutting. Used for decision.

  The refractory brick furnace wall of a coke oven processed by such a laser processing apparatus 100 is often worn or missing damaged at a depth of about 10 mm or more due to its use over a long period of time. In laser shaping, the thickness of the refractory brick to be cut is not necessarily constant. In addition, there is a part of the brick surface where carbon adheres during the coke production process, and the laser light absorption state is different from that of the solid brick surface, so there is a laser depending on whether carbon is attached or not. Processing speed (cuttable speed) is different. Here, in the case of conventional laser cutting that cuts a material with a constant thickness, it is transmitted from the back surface of the material to be cut by precisely setting a predetermined laser output, laser focusing conditions, laser operation speed, and the like. It is possible to set desired laser conditions that minimize the excessive laser output.

  However, as described above, in cutting of a refractory brick whose remaining thickness varies depending on the site and whose remaining thickness is unknown, the state in which the laser beam is transmitted to the back of the refractory brick is cut only by setting a certain cutting condition. Since it always changes according to the part, the laser output that passes through the back surface cannot be suppressed. That is, there is no constant laser cutting condition for keeping the excessive laser output transmitted from the cut back surface low. Therefore, in the laser processing apparatus 100 according to the present embodiment, the pre-cutting prior to shaping cutting estimates the remaining thickness of the refractory brick at the cutting position and determines the cutting conditions (output intensity and cutting speed) by the laser during shaping cutting. To do. Thereby, in shaping cutting, the excessive laser output which permeate | transmits a refractory brick back can be reduced as much as possible.

<2. Laser processing method>
Hereinafter, based on FIG. 3, a laser processing method using the laser processing apparatus 100 according to the present embodiment will be described. FIG. 3 is a flowchart showing a laser processing method using the laser processing apparatus 100 according to the present embodiment.

  Before starting the laser processing by the laser processing apparatus 100, the cutting position by the laser is determined. In the present embodiment, cutting by the laser processing apparatus 100 is performed in order to shape the periphery of the hole H in the refractory brick furnace wall. For this reason, first, the surface of the refractory brick furnace wall is scanned by the broken hole detection device 210 (step S100), and the broken hole H generated in the furnace wall is detected (step S110). The hole detection device 210 continues scanning the furnace wall while the hole H is not detected.

  On the other hand, when the broken hole detection device 210 detects a broken hole H as shown in FIG. 4, for example, the cutting position determining device 220 determines the cutting position of the refractory brick furnace wall (step S120). The cutting position can be specified by a cutting line that roughly includes the broken hole H based on the shape of the embedded brick or the like. For example, as shown in FIG. 4, in the z direction (vertical direction), the cutting position is substantially the same as the fracture surface of the broken hole H, and in the x direction (horizontal direction), the intermediate position in the z direction of the refractory brick 10 is set. By setting the cutting position, it is possible to set a substantially rectangular cutting position including cutting lines L1, L21, L22, L3, L41, and L42. When the cutting position of the refractory brick furnace wall is determined by the cutting position determination device 220, the cutting position of the refractory brick furnace wall is notified to the laser processing apparatus 100, and the shaped cutting by the laser processing apparatus 100 is started.

  In the laser processing according to the present embodiment, preliminary processing for determining the cutting conditions (output intensity and cutting speed) by the laser at the time of shaping and cutting is performed before shaping and cutting the refractory brick furnace wall (step S130). Preliminary processing is capable of reliably cutting the refractory brick 10 at the cutting position at the time of shaping and cutting, and not reaching other refractory bricks behind the refractory brick furnace wall to be processed as viewed from the laser processing apparatus 100. Laser cutting conditions (output intensity and cutting speed) are determined. Specifically, the laser processing apparatus 100 estimates the remaining thickness of the refractory brick at the cutting position, refers to the laser information storage unit 124, and outputs an appropriate laser output for cutting the refractory brick 10 having the estimated remaining thickness, and Determine the cutting speed.

  The estimation of the remaining thickness of the refractory brick 10 at the cutting position is, for example, the time required from the start of laser beam irradiation to the refractory brick 10 to the penetration of the refractory brick 10 or the laser pulse output until the refractory brick 10 is penetrated. Can be performed based on the number of irradiations.

  First, in order to estimate the remaining thickness of the refractory brick 10, it is necessary to detect that the refractory brick 10 has penetrated. For example, it can be specified from the emission intensity from the surface of the refractory brick by the irradiation of laser light. Here, the relationship between the output of a laser beam and the emitted light intensity from the surface of a refractory brick is shown in FIG.

  When the refractory brick 10 is irradiated with laser light, the laser light is absorbed near the refractory brick surface, the temperature of the refractory brick surface rises, and reaches the melting or evaporation temperature. During this time, the light emission near the laser light irradiation point increases the light emission intensity as the temperature of the corresponding part rises, and the light emission intensity changes as in the period T1 in FIG. Then, excavation in the thickness direction of the refractory brick 10 proceeds by continuing the laser light irradiation, but in such a period T2, light emission from the bottom of the hole being excavated is mainly observed on the surface of the refractory brick. As shown in FIG. 5, the emission intensity changes at a substantially constant value.

  When the laser beam reaches the back surface of the refractory brick 10 and a through hole is formed in the refractory brick 10, the portion heated by the laser light irradiation is reduced only to the peripheral portion of the through hole. Decreases rapidly (period T3). After that, even if laser beam irradiation is continued, the emission intensity is weakened by heating around the cutting kerf (period T4). Based on such a change in light emission intensity from the surface of the refractory brick, it is possible to identify the point in time when the refractory brick 10 has penetrated.

  Using this technique, for example, it is possible to measure the time (irradiation time) from the start of laser light irradiation until the refractory brick 10 penetrates. Here, when the output intensity of the laser beam is made constant, generally, as the thickness of the refractory brick 10 is larger, the irradiation time of the laser beam for penetrating the refractory brick 10 becomes longer. For example, there is a substantially proportional relationship as shown in FIG. 6 between the thickness of the refractory brick 10 and the irradiation time of the laser beam until penetration when the laser output is 10 kW and the condensing diameter is 0.5 mm. From this relationship, the remaining thickness of the refractory brick 10 can be estimated from the irradiation time of the laser light until the refractory brick 10 is penetrated.

  In addition, for example, in the preliminary processing, it is possible to irradiate the refractory brick 10 with a laser pulse and measure the number of irradiations from the start of laser irradiation to the penetration of the refractory brick 10. The excavation of the refractory brick 10 progresses as the number of times of irradiation of the laser pulse irradiated to the refractory brick increases. And it can detect that the refractory brick 10 penetrated from the emitted light intensity of the refractory brick surface. For example, FIG. 7 shows the relationship between the number of times of irradiation and the average value of the emission intensity on the surface of the refractory brick at the irradiation point when the refractory brick 10 is irradiated with a laser pulse. Here, a laser pulse with a laser output of 10 kW was repeatedly irradiated with a laser pulse time of 30 msec. As shown in FIG. 7, a substantially constant light emission intensity was detected until the number of times of laser pulse irradiation was 25. However, the light emission intensity rapidly decreased after 25 times. From the relationship between the processing state shown in FIG. 5 and the emission intensity of the laser, it can be seen that the refractory brick 10 has penetrated when the laser pulse was irradiated 25 times.

  Thus, when the relationship between the number of times of laser pulse irradiation necessary for penetrating the refractory brick 10 and the brick thickness was examined, it was found that there was a proportional relationship as shown in FIG. As the thickness of the refractory brick 10 increases, the number of times of laser pulse irradiation also increases. Moreover, it turned out that the depth of the refractory brick 10 processed by one laser pulse irradiation is about 3.0 mm from FIG. Therefore, it is possible to estimate the remaining thickness of the refractory brick 10 by measuring the number of times of irradiation of the laser pulse irradiated before penetrating the refractory brick 10.

  Returning to the description of FIG. 3, in the preliminary processing in step S <b> 130, the irradiation control unit 122 of the laser processing apparatus 100 that has received the notification of the cutting position causes the output intensity determination processing unit 123 to perform a cutting condition with laser during shaping cutting ( This is started by instructing the start of the determination process of output intensity and cutting speed. The irradiation control unit 123 instructs the irradiation control unit 122 to continuously irradiate or pulse the laser to the refractory brick 10 with a predetermined laser output (for example, 10 kW) during preset preliminary processing.

  The irradiation control unit 122 drives the laser irradiation device 110 to irradiate the refractory brick 10 with laser until the refractory brick 10 at the irradiation position penetrates. At this time, the output intensity determination processing unit 123 measures the irradiation time by the timer unit 1232 when continuously irradiating the laser, and measures the number of irradiations by the counting unit 1233 when irradiating the laser with pulses. And when the luminescence intensity on the surface of the refractory brick measured by the luminescence intensity measuring device 117 becomes equal to or less than the predetermined value, the irradiation control unit 122 determines that the refractory brick 10 has penetrated, and the output intensity determination processing unit 123 determines the determination result. To be notified. The output intensity determination unit 1231 of the output intensity determination processing unit 123 that has received the notification of the penetration of the refractory brick 10 acquires the irradiation time until the refractory brick 10 penetrates from the timer unit 1232 or the refractory brick 10 penetrates. The number of irradiation until is acquired from the count unit 12333.

  Based on the acquired irradiation time, the output intensity determination unit 1231 determines the refractory brick 10 at the laser preliminary processing position based on the relationship between the laser irradiation time stored in advance in the laser information storage unit 124 and the estimated brick thickness. Estimate the remaining thickness. When the number of times of irradiation is acquired, the output intensity determining unit 1231 determines the number of times of irradiation of the laser previously stored in the laser information storage unit 124 and the estimated brick thickness, and the refractory bricks at the laser pre-processing position. A remaining thickness of 10 can be estimated.

  And the output intensity determination part 1231 determines the appropriate laser cutting conditions (laser output, cutting speed) when shaping and cutting the firebrick 10 having the estimated remaining thickness. The relationship between the brick thickness and the laser cutting condition is stored in advance in the laser information storage unit 124, and the output intensity determination unit 1231 acquires the laser cutting condition associated with the estimated brick thickness from the laser information storage unit 124. Thus, the laser cutting conditions at the time of shaping cutting can be determined.

[Setting of laser cutting conditions]
Here, an example of a method for setting an appropriate laser cutting condition will be described. Appropriate laser cutting conditions in laser processing can be experimentally determined using the apparatus shown in FIG. First, a cutting brick (cutting test brick 12) was installed in the heating furnace 300, and the heating furnace 300 was heated to about 1000 ° C. The heating temperature is a temperature close to the temperature at the time of cutting the refractory brick in the actual furnace. For example, when the actual furnace is heated to 1000 ° C., the temperature of the heating furnace 300 may be set in the range of about 700 to 1300 ° C. in the experiment, thereby verifying the cutting ability equivalent to that of the actual furnace. be able to.

  Next, the doors 201 and 202 before and after the heating furnace 300 were opened, laser light was irradiated from the front surface, and a laser output meter was installed on the rear surface to measure the laser output at the rear. In this experiment, a laser output of 10 kW was continuously output, the laser condensing diameter was set to 0.5 mm, and the focal position was adjusted so that the condensing focal point was located on the surface of the cutting test brick 12. At this time, cutting was performed by spraying dry air at 200 L / min from the tip of the nozzle.

  Under such conditions, the laser processing head unit U1 was moved at a speed V (mm / min), and the laser output observed on the back surface of the cutting test brick 12 during cutting was measured. At this time, the laser output meter on the back surface of the cutting test brick 12 was also moved in synchronization with the laser processing head unit U1 to measure the laser output.

  In this experiment, the laser cutting condition that is not excessive was determined not to damage the adjacent refractory brick furnace wall. That is, the condition that the measured value by the laser output meter on the back surface of the cutting test brick 12 was 1 kW or less was set as an appropriate laser cutting condition. Then, the thickness of the cutting test brick 12 is changed by 10 mm from 20 mm to 150 mm, and the cutting speed V at which the measured value by the laser output meter (that is, the laser transmission output from the back surface of the cutting test brick 12) is 1 kW or less. It was determined.

  Thus, when the condition that the value of the excess output transmitted to the back surface of the brick is 1 kW or less with respect to the thickness of the cutting test brick 12 is acquired, these are stored in the laser information storage unit 124 as the laser cutting condition. To be recorded. The output intensity determination unit 1231 can determine the laser cutting conditions at the time of shaping and cutting based on a table representing the relationship between the brick thickness and the laser cutting conditions stored in the laser information storage unit 124.

  Laser cutting conditions are determined by four basic parameters: laser output (kW), laser focused diameter (mmφ), laser moving speed (mm / min), nozzle diameter and air injection amount (L / min). Here, there are an infinite number of combinations of the laser output and the laser moving speed even if the laser condensing diameter and the air injection amount are the same. In order to determine one combination from an infinite combination of the laser output and the laser moving speed, for example, in consideration of increasing productivity, it is possible to set a condition for increasing the laser moving speed as much as possible. Such conditions are based on the fact that, when cutting a refractory brick with the brick thickness to be cut as a fixed value, the higher the laser output, the faster the laser moving speed can be cut. In this experiment, the laser moving speed is further increased by setting the laser output to the maximum (for example, 10 kW) and determining the laser cutting conditions. When the laser moving speed is increased, the excess output transmitted to the back surface can be reduced with respect to the thickness that can be cut, and therefore the laser moving speed may be determined according to the brick thickness at the cutting position.

However, if the laser moving speed is increased too much, the excessive output becomes small, but stable cutting cannot be performed. Therefore, an appropriate range of the laser moving speed can be set to be larger than the speed V _{1 at} which the back surface excess output becomes 1 kW or less and the maximum speed V _{2 that} can be stably cut with the brick thickness. That is,
V ₁ <V ≦ V ₂
It becomes. In practice, for example, a laser movement speed may be set to V _2.

  If the remaining brick thickness is too thin, the laser moving speed required to make the excessive output to the back surface 1 kW or less becomes too fast under the condition that the laser output is kept constant at 10 kW. Due to hardware limitations, there is a possibility that the required laser moving speed cannot be set. In this case, the laser information storage unit 124 further stores, for example, a table representing the relationship between the laser moving speed for each brick thickness and the excess output to the back surface when the laser output is reduced to 5 kW, and the remaining brick thickness. Is less than a predetermined value, for example, 30 mm or less, the laser output is reduced from 10 kW to 5 kW, and based on the table showing the laser cutting conditions when the laser output is 5 kW, the laser cutting condition that the excess output to the back surface is 1 kW or less Can be determined.

  Of the four basic parameters of the laser cutting conditions described above, when conditions such as laser output and laser focusing diameter are different, the cutting speed V at which the laser transmission output from the back surface of the cutting test brick 12 is 1 kW or less is Come different. Also in this case, an appropriate laser cutting condition can be determined by the same method as described above.

In addition, damage to the adjacent refractory brick furnace wall is caused by the laser power transmitted from the back side of the refractory brick and the laser beam diameter when the laser is irradiated to the adjacent refractory brick furnace wall (the condenser lens used and It is determined by the distance between adjacent refractory brick furnace walls) and the moving speed of the laser light, that is, the cutting speed. For example, when a condensing lens with a short focal length is used, the spread of the laser transmitted to the back side of the refractory brick to be cut is large, and the laser power density (kW / cm ² ) on the surface of the adjacent refractory brick furnace wall is reduced, Adjacent refractory brick furnace walls are difficult to machine. That is, the damage to the adjacent refractory brick furnace wall is reduced.

  In addition, the setting method of the laser cutting condition which does not damage an adjacent refractory brick furnace wall is an example in one laser processing apparatus, Comprising: It changes suitably according to the change of the structure of a laser processing apparatus, or the structure of a coke oven. Is.

  Returning to the description of FIG. 3, the preliminary processing is performed at one or more positions on the cutting line determined by the cutting position determining device 200. By performing the preliminary processing at a plurality of points, even when the remaining thickness of the refractory brick 10 on the cutting line is different, processing can be performed under appropriate laser cutting conditions according to each thickness. For example, as shown in FIG. 4, when cutting lines L1, L21, L22, L3, L41, and L42 are set, for example, points C1 to C4, D1 to D4 that correspond to both end positions of each line, Preliminary processing may be performed at an intermediate point of the line, and the remaining thickness of the refractory brick 10 may be estimated. By performing preliminary processing at a plurality of positions, it becomes possible to recognize a change in the thickness of the refractory brick 10 in the cutting line, and it is possible to set the laser cutting conditions at the time of shaping and cutting more accurately.

  When preliminary processing is performed in step S130 and the laser cutting conditions for shaping and cutting the refractory brick 10 are determined, the irradiation control unit 122 cuts the refractory brick 10 along the cutting line with the determined laser cutting conditions. The laser irradiation device 110 is controlled. At this time, the laser irradiation device 110 is moved by the moving mechanism 130 controlled by the position control unit 121. In this manner, the refractory brick furnace wall is shaped and cut at the cutting position (step S140).

  And the irradiation control part 122 determines whether the shaping cutting of the refractory brick 10 in a cutting line was completed (step S150), and when the shaping cutting of the refractory brick 10 in all the cutting lines has been completed. Then, the laser processing is finished. On the other hand, when the shaping cutting of the refractory bricks 10 in all the cutting lines has not been completed, the process returns to step S130, and the preliminary processing (step S130) and the shaping cutting of the refractory brick furnace wall (step S140) are repeated. In the laser processing shown in FIG. 3, the preliminary processing and the shaped cutting are repeated for each cutting line to be cut in one process, but the present invention is not limited to such an example. For example, after all the cutting lines are preliminarily processed, the refractory bricks 10 may be collectively cut.

  The laser processing apparatus 100 according to the present embodiment and the laser processing method using the laser processing apparatus 100 have been described above. According to this embodiment, when shaping and cutting the periphery of the broken hole H generated in the refractory brick furnace wall, first, the remaining thickness of the refractory brick 10 at the cutting position is estimated by preliminary processing, and the estimated remaining thickness Appropriate laser cutting conditions for the refractory brick 10 are determined. Then, by cutting the refractory brick furnace wall based on the determined laser cutting conditions, it is possible to prevent the refractory brick furnace wall other than the object to be cut from being damaged by being processed with an excessive laser output.

<3. Example>
The laser processing apparatus 100 according to the present embodiment laser-processed the refractory brick furnace wall and verified its effectiveness. As the laser processing apparatus 100, the apparatus shown in FIGS. 1 and 2 was used. The temperature of the refractory brick furnace wall to be processed by the laser processing apparatus 100 is about 1000 ° C. Further, as shown in FIG. 14, the refractory brick furnace walls are provided at predetermined intervals so as to alternately form carbonization chambers and combustion chambers. At this time, the refractory brick furnace wall 1C of the adjacent kiln is present at a distance of about 500 mm from the refractory brick furnace wall 1B to be processed in which the hole H has occurred.

  When the periphery of the hole H of the refractory brick furnace wall to be processed is viewed from the carbonization chamber side, it is as shown in FIG. As described above, the shape of the hole H is substantially parallel in cross section in the z direction (up and down direction), but the cross section in the x direction (left and right direction) is tapered. That is, in the line direction of the cutting lines L1 and L3 shown in FIG. 4, the portion that is thinner and thinner than the original refractory brick is cut.

  As the laser irradiation device 110, a fiber laser installed outside the furnace was used, and laser light was transmitted to the laser processing head unit U1 through the optical fiber 111. The whole adiabatic cooling box was moved up and down and left and right by the manipulator 106, and the laser beam irradiation point was operated. The laser focused spot diameter on the surface of the refractory brick furnace wall for cutting the refractory brick was 0.5 mm.

First, in a state where the laser head was stopped, the laser head was moved to a substantially middle point of the cutting line L1, and the refractory brick furnace wall was irradiated with laser light at a laser output of 10 kW. From the processing nozzle 116, about 200 L / min of dry air is blown toward the laser beam irradiation portion coaxially with the laser beam to prevent spatter scattering to the laser processing head portion U1, and from the back surface of the refractory brick furnace wall to the combustion chamber. The brick melt was discharged near the laser beam irradiation point. In this embodiment, it is a processing method for removing the refractory bricks, and it is desirable that the power density of the laser light be 1000 W / mm ² or more in order to efficiently perform melting.

  For the measurement of the emission intensity at the laser beam irradiation point, a CCD camera was used as the emission intensity measuring device 117 installed coaxially with the laser. In addition to the CCD camera, for example, a photodiode can be used as the emission intensity measuring device 117. The emission intensity at the laser irradiation point is obtained by integrating the luminance value of the CCD camera cell that detects a luminance signal equal to or higher than a predetermined luminance threshold value for removing the luminance value when the laser is not irradiated, from the image captured by the CCD camera. It was supposed to be. The change in emission intensity from the start of laser light irradiation is as shown in FIG. The period T in FIG. 5 is the penetration time.

  Here, the laser information storage unit 124 of the laser processing apparatus 100 stores the relationship between the time required for penetration of the refractory bricks previously investigated and the brick thickness shown in FIG. When the laser output is the same, the time until the refractory brick penetrates is proportional to the brick thickness. Therefore, it is possible to estimate the remaining thickness of the refractory brick at the laser irradiation position by measuring the penetration time with the timer unit 1232. When the laser output was 2 kW or less, the penetration depth of the refractory brick was less than 100 mm. Therefore, when cutting refractory bricks of 100 mm or more, it is desirable that the laser output be 2 kW or more.

  The penetration time T of the refractory brick in this example was 0.80 seconds. From this, the remaining thickness of the refractory brick is estimated to be 72 mm. Therefore, the laser processing head unit U1 is moved to the point C4, continuously output at a laser output of 10 kW, the cutting speed is 40 mm / min, the laser processing head unit U1 is moved to the point C1, and the cutting line L1 around the hole H is cut. The cutting was performed. As a result, the cutting line L1 could be cut without a defective portion. Moreover, the damage by having irradiated the laser beam to the refractory brick furnace wall adjacent to the refractory brick furnace wall to be processed was not observed. Furthermore, when the thickness of the cut surface was measured after cutting, the thickness of the cut brick was in the range of 72 mm ± 2 mm, and it was confirmed that the remaining thickness estimation by the method according to the present embodiment is effective.

  Next, the laser output and the movement of the laser processing head unit U1 were once stopped at the end point C1 of the cutting line L1, and then preliminary processing and shaping cutting were performed on the cutting lines L21 and L22. The cutting lines L21 and L22 are portions where the initial brick thickness (110 mm) is likely to remain.

  First, the laser processing head unit U1 was moved to a substantially middle point of the cutting line L21 and irradiated with laser, and the penetration time until the refractory brick penetrated was measured in the same manner as in Example 1. The laser irradiation conditions at this time were a continuous output with a laser output of 10 kW and a laser focused diameter of 0.5 mm. From the processing nozzle 116, about 200 L / min of dry air is blown toward the laser beam irradiation portion coaxially with the laser beam to prevent spatter scattering to the laser processing head portion U1, and from the back surface of the refractory brick furnace wall to the combustion chamber. The brick melt was discharged near the laser beam irradiation point. For the measurement of the emission intensity at the laser beam irradiation point, a CCD camera was used as the emission intensity measuring device 117 installed coaxially with the laser. The light emission intensity is an integrated value of the luminance values of the CCD camera cell that detects a luminance signal equal to or higher than a preset luminance threshold value for an image captured by the CCD camera.

  As a result of the same measurement as in Example 1, the penetration time T until the refractory brick penetrated was 0.65 seconds. Referring to FIG. 6, the thickness of the refractory brick at the laser irradiation position is estimated to be 58 mm. Accordingly, the laser cutting conditions for the cutting lines L21 and L22 are determined to be a laser output of 10 kW (continuous output) and a cutting speed of 48 mm / min. Under this determined laser cutting condition, the laser beam is irradiated while moving the laser processing head unit U1 of the laser processing apparatus 100 from the point C1 to the point D1, and the refractory brick is shaped and cut along the cutting line L21. In this example, in consideration of the error of the estimated thickness, a slight margin was given, and when the brick thickness was 60 mm, the shaped cut was performed under an appropriate laser output condition.

  After the cut cutting of the cutting line L21, when the cut piece was collected and its thickness was measured, it was about 108 mm thick. That is, although the brick thickness of 108 mm was present at the position of the cutting line L21, laser cutting was facilitated by the introduction of cracks. Therefore, the laser cutting conditions for processing a refractory brick thickness of 60 mm without cracks. It is thought that it was possible to cut the firebrick sufficiently.

  If the laser cutting conditions are set assuming that the brick thickness remains 110 mm, it is possible to cut a refractory brick having a brick thickness approximately twice as large, and excessive laser cutting conditions are selected. In this case, it is considered that there was a high possibility that the excess laser beam was irradiated to the adjacent healthy refractory brick furnace wall and caused a large damage to the furnace wall. However, in this embodiment, since the remaining thickness is estimated by actually irradiating the laser, the estimated remaining thickness can be regarded as an effective thickness viewed from the viewpoint of laser processing, not an apparent thickness. Since the laser cutting condition is set based on the remaining thickness of the refractory brick at the estimated processing position, the refractory brick can be shaped and cut under an appropriate laser cutting condition.

  The cutting line L21 could be cut without a defective part. Moreover, the damage by having irradiated the laser beam to the refractory brick furnace wall adjacent to the refractory brick furnace wall to be processed was not observed.

  Next, preliminary processing and shaping cutting were performed on the cutting line L22 as in the case of the cutting line L21. Preliminary processing was performed at a substantially intermediate point of the cutting line L22 with a laser output condition of a laser output of 10 kW and a laser focused diameter of 0.5 mm, and the remaining thickness of the refractory brick at the irradiation position was estimated to be 56 mm. . Accordingly, the laser cutting conditions of the cutting line L22 were determined to be a laser output of 10 kW (continuous output) and a cutting speed of 50 mm / min. And the laser beam was irradiated, moving the laser processing head part U1 of the laser processing apparatus 100 from the point D2 to the point C2 according to the determined laser cutting conditions, and the refractory brick was shaped and cut by the cutting line L22. The cutting line L22 could also be cut without a defective part. Moreover, the damage by having irradiated the laser beam to the refractory brick furnace wall adjacent to the refractory brick furnace wall to be processed was not observed.

  After the cut cutting of the cutting line L22, the cut piece was collected and its thickness was measured. As a result, the thickness was about 108 mm. That is, although the brick thickness of 108 mm was present at the position of the cutting line L22, laser cutting was facilitated by the introduction of cracks. Therefore, the laser cutting conditions for processing a refractory brick thickness of 50 mm without cracks. It is thought that it was possible to cut the firebrick sufficiently.

  Next, the laser output and the movement of the laser processing head unit U1 were once stopped at the end point C2 of the cutting line L22, and then preliminary processing and shaping cutting were performed on the cutting line L3. Like the cutting line L1, the cutting line L3 is a portion where the refractory brick is broken in a taper shape, and thus the remaining thickness of the refractory brick is likely to be thinner than the original thickness. Therefore, in the cutting line L3, preliminary processing is performed at the positions of two equal dividing points (M31 and M32 in order from the point C2 side) when the cutting line L3 is equally divided into three, and the laser cutting conditions at the time of shaping cutting are determined. did.

  In the preliminary processing of Example 3, a laser pulse was irradiated to the refractory brick, and the number of irradiation until the refractory brick penetrated was measured. The laser irradiation conditions at this time were a pulse output with a laser output of 10 kW and an output duration of 30 msec, and a laser focused diameter of 0.5 mm. The laser pulse is repeatedly irradiated until the penetration of the refractory brick is confirmed. From the processing nozzle 116, about 200 L / min of dry air is blown toward the laser beam irradiation portion coaxially with the laser beam to prevent spatter scattering to the laser processing head portion U1, and from the back surface of the refractory brick furnace wall to the combustion chamber. The brick melt was discharged near the laser beam irradiation point. For the measurement of the emission intensity at the laser beam irradiation point, a CCD camera was used as the emission intensity measuring device 117 installed coaxially with the laser. The light emission intensity is an integrated value of the luminance values of the CCD camera cell that detects a luminance signal equal to or higher than a preset luminance threshold value for an image captured by the CCD camera.

  For example, it is assumed that the relationship between the number of times of laser beam irradiation at the point M31 and the emission intensity on the surface of the refractory brick is as shown in FIG. The emission intensity at the time of laser irradiation gradually decreased from the start of laser light irradiation to the 24th pulse, but the amount of decrease in the emission intensity increased at the 25th pulse, and the emission intensity was less than half at the 26th pulse irradiation. The emission intensity decreased rapidly. Furthermore, although irradiation was performed 5 times, the emitted light intensity remained falling. From this, at the point M31, it can be estimated that the refractory brick penetrated during the 25th pulse irradiation.

  When the number of times of irradiation until the refractory brick penetrated was measured by irradiating the laser pulse at the point M32 by the same method, 25 pulses were obtained as in the point M31. And if the frequency | count of irradiation until a refractory brick penetrates in each preliminary processing position is measured, the residual thickness of the refractory brick in the said position can be estimated from the relationship between the frequency | count of irradiation shown in FIG. 8, and brick thickness. From FIG. 8, when the number of times of irradiation until the refractory brick penetrates is 25, the remaining thickness is estimated to be 75 mm.

  Based on the above results, the laser cutting conditions of the cutting line L3 were determined to be a laser output of 10 kW (continuous output) and a cutting speed of 38 mm / min. And the laser beam was irradiated, moving the laser processing head part U1 of the laser processing apparatus 100 from the point C2 to the point C3 according to the determined laser cutting conditions, and the refractory brick was shaped and cut by the cutting line L3. The cutting line L3 could also be cut without a defective portion. Moreover, the damage by having irradiated the laser beam to the refractory brick furnace wall adjacent to the refractory brick furnace wall to be processed was not observed. Further, when the thickness of the cut surface was measured after cutting, the thickness of the cut brick was in the range of 75 mm ± 3 mm, and it was confirmed that the remaining thickness estimation by the method according to the present embodiment is effective.

  In the preliminary processing of the present example, a method of estimating the remaining thickness of the refractory brick based on the number of irradiation times until the refractory brick penetrates by pulsing the laser was adopted. Here, as in Examples 1 and 2, in the method in which the laser is continuously output to perform penetration processing of the refractory brick and the penetration time is measured, for example, the processing speed in the depth direction is about 90 mm under the processing conditions of FIG. In order to estimate the remaining thickness with an accuracy of mm, it is necessary to determine the penetration time in msec. For this reason, there is a limit to the accuracy of estimation of the remaining thickness. If the laser output is not stopped simultaneously with the penetration, the refractory brick furnace wall adjacent to the refractory brick wall will be damaged by the penetration process which is a preliminary process.

  On the other hand, in the method of pulsing a laser and estimating the remaining thickness of the refractory brick based on the number of irradiation until the refractory brick penetrates, processing with one pulse is performed by accurately setting the pulse width of the laser pulse to be used. It becomes possible to control the progress speed. In this example, the pulse width was 30 msec, and the processing progress in the depth direction per pulse was 3 mm. That is, it is possible to estimate the remaining thickness of the refractory brick with an accuracy of about 3 mm or less by the number of times of irradiation until the refractory brick penetrates. As the laser pulse irradiation condition, the larger the progress of processing in the depth direction in one pulse, the larger the estimation error of the remaining thickness. Therefore, it is desirable to set the laser pulse irradiation condition so that the machining progress in the depth direction is 5 mm or less per pulse, and in particular, the progress in the depth direction is about 2-3 mm or less per pulse. By setting so that it is possible, the estimation precision of remaining thickness can be improved more.

  Further, in this example, for confirmation, when it is estimated that further 5 pulses are irradiated after the 26th pulse where it is estimated that the refractory brick has penetrated, and the emission intensity at that point is not penetrating. It was confirmed that the luminescence intensity was lower than that. In the embodiment, the pulse width is short and the machining capability is limited to be smaller than that of continuous output. Thereby, laser irradiation for confirmation of penetration can be performed without damaging the adjacent refractory brick furnace wall, and penetration determination can be performed reliably.

  Next, after the laser output and the movement of the laser processing head unit U1 were temporarily stopped at the end point C3 of the cutting line L3, preliminary processing and shaping cutting were performed on the cutting lines L41 and L42. The cutting lines L41 and L42, like the cutting lines L21 and L22, remain approximately the same as the original brick thickness (110 mm), but there is a high possibility that laser cutting is easy due to cracks. Part. Therefore, similarly to the cutting lines L21 and L22, the laser processing head unit U1 is moved to a substantially intermediate point between the cutting lines L41 and L42, and preliminary processing is performed to determine the laser cutting conditions at the time of shaping cutting.

  In the preliminary processing of Example 4, similarly to Example 3, the number of times of irradiation until the refractory brick penetrated was measured by irradiating the refractory brick with a laser pulse. The laser irradiation conditions at this time were a pulse output with a laser output of 10 kW and an output duration of 30 msec, and a laser focused diameter of 0.5 mm. The laser pulse is repeatedly irradiated until the penetration of the refractory brick is confirmed. From the processing nozzle 116, about 200 L / min of dry air is blown toward the laser beam irradiation portion coaxially with the laser beam to prevent spatter scattering to the laser processing head portion U1, and from the back surface of the refractory brick furnace wall to the combustion chamber. The brick melt was discharged near the laser beam irradiation point. For the measurement of the emission intensity at the laser beam irradiation point, a CCD camera was used as the emission intensity measuring device 117 installed coaxially with the laser. The light emission intensity is an integrated value of the luminance values of the CCD camera cell that detects a luminance signal equal to or higher than a preset luminance threshold value for an image captured by the CCD camera.

  As in Example 3, as a result of measuring the number of laser pulse irradiations and the change in the light emission intensity at the laser light irradiation point at a substantially intermediate point between the cutting lines L41 and L42, the light emission intensity was less than half in the 13th pulse irradiation. A drastic drop was observed. From this, the number of irradiation times of the laser pulse necessary for penetration of the refractory brick was 12 pulses, and the remaining thickness of the refractory brick in the cutting lines L41 and L42 was estimated to be 36 mm. Based on the above results, the laser cutting conditions of the cutting lines L41 and L42 were determined to be a laser output of 10 kW (continuous output) and a cutting speed of 80 mm / min. Then, according to the determined laser cutting conditions, laser light is irradiated while moving the laser processing head unit U1 of the laser processing apparatus 100 from the point C3 to the point D3 and from the point D4 to the point C4, and fireproofing is performed at the cutting lines L41 and L42. The brick was cut and cut. The cutting lines L41 and L42 could also be cut without a defective portion. Moreover, the damage by having irradiated the laser beam to the refractory brick furnace wall adjacent to the refractory brick furnace wall to be processed was not observed.

  After the cutting and cutting of the cutting lines L41 and L42, the cut piece was collected and its thickness was measured. As a result, the thickness was about 108 mm. That is, the brick thickness of 108 mm was present at the positions of the cutting lines L41 and L42, but laser cutting was facilitated by the introduction of cracks, so the laser when processing a fire-resistant brick thickness of 36 mm without cracks. It is thought that the firebrick could be cut sufficiently under the cutting conditions.

  By the above-described methods of Examples 1 to 4, the periphery of the pierced hole H formed in the refractory brick furnace wall is shaped and cut, and by cutting into a rectangular shape, the shaped and cut necessary for repairing the refractory brick can be performed. It was. At this time, the sound fire brick wall surface adjacent to the cut fire brick wall was not damaged by laser cutting.

  In the above embodiment, preliminary processing and shaping / cutting were performed with a laser focused diameter of 0.5 mm, a laser output of 10 kW, and a laser pulse width of 30 msec. However, the laser conditions are not limited to this example. For example, in preliminary processing, it is only necessary to obtain the laser irradiation time or the number of times of laser pulse irradiation until the refractory brick penetrates in order to estimate the remaining thickness of the refractory brick. Conditions may be set as appropriate.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the pierced hole detection process, the cutting position determination process, the preliminary processing, and the shaped cutting of the refractory brick furnace wall are automatically performed by the pierced hole detection apparatus 210, the cutting position determination apparatus 220, and the laser processing apparatus 100. However, the present invention is not limited to such an example. For example, it may be performed according to a user instruction such as starting a part of processing.

DESCRIPTION OF SYMBOLS 10 Refractory brick 100 Laser processing apparatus 105 Heat insulation cooling box 106 Manipulator 110 Laser irradiation apparatus 111 Optical fiber 112 Collimator head 113 Reflection mirror 114 Condensing lens 115 Transmission window 116 Processing nozzle 117 Luminous intensity measuring device 118 Lens 119 Optical filter 120 Control apparatus 121 Position control unit 122 Irradiation control unit 123 Output intensity determination processing unit 1231 Output intensity determination unit 1232 Timer unit 1233 Count unit 124 Laser information storage unit 130 Moving mechanism 210 Hole detection device 220 Cutting position determination device U0 Laser light output unit U1 Laser processing Head unit U2 Processing observation unit

Claims (6)

When repairing the broken hole generated in the refractory brick furnace wall that separates the carbonization chamber and the combustion chamber of the coke oven with heat, the surface of the refractory brick furnace wall is irradiated with laser light to surround the broken hole part. A laser processing apparatus for shaping and cutting
A laser irradiation unit for irradiating the refractory brick furnace wall surface with laser light;
A light emission intensity measuring unit for measuring light emission intensity at a laser beam irradiation point on the surface of the refractory brick furnace wall;
Based on the measurement result of the emission intensity measurement unit, a control unit for controlling the laser irradiation unit according to the laser cutting conditions of the refractory brick furnace wall,
With
The controller is
A laser information storage unit for storing a laser cutting condition for the thickness of the refractory brick set in advance;
Before shaping and cutting the periphery of the pierced part, the surface of the refractory brick furnace wall is preliminarily irradiated with laser light at an arbitrary position on the cutting line for cutting the refractory brick furnace wall, and the remaining thickness of the refractory brick A processing condition determination processing unit that determines a laser cutting condition at the time of shaping and cutting the refractory brick furnace wall with reference to the laser information storage unit based on the estimation result,
Based on the laser cutting conditions determined by the processing condition determination processing unit, a drive control unit that controls the output intensity of the laser light of the laser irradiation unit and the moving speed of the laser irradiation unit;
A laser processing apparatus comprising: The laser information storage unit stores the relationship between the thickness of the refractory brick and the irradiation time of the laser light until the refractory brick penetrates when the refractory brick is continuously irradiated with laser light,
The processing condition determination processing unit is characterized in that the remaining thickness is estimated based on an irradiation time from the start of irradiation of the laser beam to the surface of the refractory brick furnace wall until the refractory brick furnace wall penetrates. The laser processing apparatus according to claim 1. The laser information storage unit stores the relationship between the thickness of the refractory brick and the number of times the laser pulse is irradiated until the refractory brick penetrates when the refractory brick is irradiated with a laser pulse.
2. The laser processing apparatus according to claim 1, wherein the processing condition determination processing unit estimates the remaining thickness based on the number of times of laser pulse irradiation until the refractory brick furnace wall penetrates.   Laser cutting conditions at the time of shaping and cutting of the refractory brick furnace wall can penetrate the refractory brick furnace wall having the remaining thickness estimated by the processing condition determination processing unit, and on the back side of the refractory brick furnace wall The laser processing apparatus according to any one of claims 1 to 3, wherein the laser processing apparatus is set so as not to reach an adjacent refractory brick furnace wall surface.   The said processing condition determination process part preliminarily irradiates a laser beam in several positions on the said cutting line, and estimates the remaining thickness of the said refractory brick, The any one of Claims 1-4 characterized by the above-mentioned. The laser processing apparatus according to item. When repairing the broken hole generated in the refractory brick furnace wall that separates the carbonization chamber and the combustion chamber of the coke oven with heat, the surface of the refractory brick furnace wall is irradiated with laser light to surround the broken hole part. Is a laser processing method of shaping and cutting with a laser processing apparatus,
A laser irradiation step of irradiating the surface of the refractory brick furnace wall with a laser beam by a laser irradiation unit;
A light emission intensity measuring step for measuring light emission intensity at a laser beam irradiation point on the surface of the refractory brick furnace wall by a light emission intensity measuring unit,
Based on the measurement result by the emission intensity measurement unit, a control step of controlling the laser irradiation unit according to the laser cutting conditions of the refractory brick furnace wall,
The control step includes
A preliminary irradiation step of pre-irradiating the surface of the refractory brick furnace wall with laser light at an arbitrary position on a cutting line for cutting the refractory brick furnace wall before shaping and cutting the periphery of the hole portion;
Based on the emission intensity at the laser beam irradiation point on the surface of the refractory brick furnace wall during the preliminary irradiation, a remaining thickness estimation step for estimating the remaining thickness of the refractory brick,
Based on the estimation result, with reference to a laser information storage unit that stores a laser cutting condition for the thickness of the refractory brick set in advance, a processing condition determination for determining a laser cutting condition at the time of shaping and cutting the refractory brick furnace wall Steps,
Based on the determined laser cutting condition, a drive control step for controlling the output intensity of the laser beam of the laser irradiation unit and the moving speed of the laser irradiation unit;
A laser processing method comprising:

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