Operatorless servicing of a boiler furnace

Abstract

A method for clearing accumulated material deposits inside a furnace includes initiating a preprogrammed sequence to: position a robot to access an opening in a wall of the furnace; position an end effector of the robot at a specified angle for accessing the opening; operate the robot to cause the end effector to penetrate the accumulated material deposits; and retract the end effector.

Description

OPERATORLESS SERVICING OF A BOILER FURNACERELATED APPLICATION

[0001] The present application claims priority from and the benefit of U.S. Provisional Patent Application No. 63 / 600,906, filed November 20, 2023, the disclosure of which is hereby incorporated herein by reference in full.BACKGROUND

[0002] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to being prior art by inclusion in this section.

[0003] A recovery boiler is used in the kraft process of pulping for recovering and reforming chemicals for white liquor from black liquor. The black liquor is burned in a furnace of the recovery boiler. Concentrated black liquor contains organic dissolved wood residue in addition to sodium sulfate from the cooking chemicals added at a digester. Combustion of the organic portion of chemicals in the recovery boiler furnace produces heat used to produce high pressure steam, which may be used to generate electricity for the facility. As a result of the combustion process, partly burned residue gathers on the bottom of the recovery boiler furnace and the reduced chemicals are continuously extracted in liquid state as molten smelt.

[0004] During normal operation, the smelt pools in the recovery boiler furnace bottom, with excess smelt overflowing through one or more openings in the recovery boiler furnace wall. This excess molten smelt flows down one or more smelt spouts which are attached to the recovery boiler furnace. FIG. 1A is a diagram illustrating an opening 110 in a recovery boiler furnace wall 120. FIG. IB is a diagram illustrating a smelt spout 130 that attaches to the recovery boiler furnace wall 120 to permit extraction of molten smelt. In normal operation of therecovery boiler furnace, the molten smelt flows through the opening 1 10 in the recovery boiler furnace wall 120 and down the smelt spout 130 into a dissolving tank (not shown). FIG. 1C is an exploded perspective view of the spout 130, the opening 110 in the furnace wall 120, and 140 located adjacent the opening 110.

[0005] Dynamic furnace upset conditions, for example unexpected recovery boiler furnace shutdown, can sometimes result in an accumulation of solid material (frozen smelt, salt cake, and / or other agglomerations) near the openings in the recovery boiler furnace wall preventing normal flow of the molten smelt from the recovery boiler furnace and down the spouts. The conventional practice requires manual clearing of the solid material inside the recovery boiler furnace, either by mechanical rodding (i.e., manually breaking up or punching through the accumulated material inside the recovery boiler furnace opening with a metal rod) or by local heating via hand-held torch to melt the solid material so it flows out. Both practices are manually performed by an operator and are difficult, dangerous, and time-consuming.SUMMARY

[0006] Systems and methods for utilizing a robot for clearing accumulated solid material inside a recovery boiler furnace are provided.

[0007] According to various aspects there is provided a system for clearing an accumulated deposit inside a furnace. In some aspects, the system may include: a robot having an end effector configured to clear the accumulated deposit inside the furnace; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate the end effector.

[0008] According to various aspects there is provided a robot for clearing accumulated deposits inside a furnace. In some aspects, the robot may include: an end effector configured to clear the accumulated deposits inside the furnace; a robot arm coupled to the end effector and configured to control a position of the end effector; a tool bit coupled to the end effector; and a plurality of sensors configured to sense a position of the end effector and torque or force appliedto the end effector. The end effector and the tool bit are configured to penetrate the accumulated deposit inside the furnace.

[0009] According to various aspects there is provided a method for clearing accumulated deposits inside a furnace. In some aspects, the method may include initiating a preprogrammed sequence to: position a robot to access an opening in a wall of the furnace; position an end effector of the robot at a specified angle for accessing the opening; operate the robot to cause the end effector to breakthrough the accumulated deposit; and retract the end effector.

[0010] According to various aspects there is provided a system for inserting a plug in an opening in a wall of a boiler furnace. In some aspects, the system may include: a robot having an end effector configured to mount a plug sized to plug the opening; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate the end effector.

[0011] According to various aspects there is provided a system for operatorless servicing of a boiler furnace. The system may include: a robot having a robot arm and one of a plurality of end effectors, each of the plurality of end effectors being configured to perform a service operation of the group consisting of: clearing an opening in a wall of the boiler furnace at least partially closed with solid smelt; collecting a sample of solid smelt from the opening; plugging the opening with a plug; and removing the plug from the opening; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate two of the end effectors to complete at least two of the service operations.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Aspects and features of the various embodiments will be more apparent by describing examples with reference to the accompanying drawings, in which:

[0013] FIG. 1 A is a perspective view illustrating an opening in a recovery boiler furnace wall;

[0014] FIG. IB is a perspective view illustrating a smelt spout that attaches to the recovery boiler furnace wall as in FIG. 1 to permit extraction of molten smelt;

[0015] FIG. 1C is an exploded perspective view of the smelt spout of FIG. IB.

[0016] FIG. 2 is a diagram illustrating a schematic representation of an example of a recovery boiler furnace with an accumulation of solid material;

[0017] FIG. 3 is a diagram illustrating an example of a robot utilized for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure;

[0018] FIG. 4 illustrates examples of tool bits that may be attached to an end effector for use with a robot for clearing accumulated solid smelt inside a recovery boiler furnace according to some aspects of the present disclosure;

[0019] FIG. 5 is diagram illustrating an example of a robot with the robot arm and end effector positioned for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure;

[0020] FIG. 6 is a diagram illustrating an example of a control system that may be used with a robot for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure; and

[0021] FIG. 7 is a flowchart illustrating an example of a method for controlling a robot for clearing a blockage inside a recovery boiler furnace according to some aspects of the present disclosure.

[0022] FIG. 8A is a perspective view of a spout plug rod to be used with the robot of FIG. 3.

[0023] FIG. 8B is a perspective view of the spout plug rod of FIG. 8 A being inserted into the opening in the recovery boiler furnace wall with the robot arm of FIG. 3.

[0024] FIG. 8C is an enlarged partial perspective view illustrating the insertion of a spout plug.

[0025] FIG. 9 is a schematic diagram illustrating a system for operatorless servicing of a boiler furnace.DETAILED DESCRIPTION

[0026] While certain embodiments are described, these embodiments are presented by way of example only, and are not intended to limit the scope of protection. The apparatuses, methods,and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the example methods and systems described herein may be made without departing from the scope of protection.

[0027] Similar reference characters indicate corresponding parts throughout the several views unless otherwise stated. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate embodiments of the present disclosure, and such exemplifications are not to be construed as limiting the scope of the present disclosure.

[0028] Except as otherwise expressly stated herein, the following rules of interpretation apply to this specification: (a) all words used herein shall be construed to be of such gender or number (singular or plural) as to circumstances require; (b) the singular terms “a,” “an,” and “the,” as used in the specification and the appended claims include plural references unless the context clearly dictates otherwise; (c) the antecedent term “about” applied to a recited range or value denotes an approximation within the deviation in the range or values known or expected in the art from the measurements; (d) the words “herein,” “hereby,” “hereto,” “hereinbefore,” and “hereinafter,” and words of similar import, refer to this specification in its entirety and not to any particular paragraph, claim, or other subdivision, unless otherwise specified; (e) descriptive headings are for convenience only and shall not control or affect the meaning or construction of any part of the specification; and (f) “or” and “any” are not exclusive and “include” and “including” are not limiting. Further, the terms, “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including but not limited to”).

[0029] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range of within any sub ranges there between, unless otherwise clearly indicated herein. Each separate value within a recited range is incorporated into the specification or claims as if each separate value were individually recited herein. Where a specific range of values is provided, it is understood that each intervening value, to the tenth or less of the unit of the lower limit between the upper and lower limit of that range and any other stated or intervening value in that stated range or subrange hereof, is included herein unless the context clearly dictates otherwise. All subranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any specifically and expressly excluded limit in the stated range.

[0030] Combustion of black liquor in the furnace of a recovery boiler results in partly burned reduced chemicals gathering on the bottom of the recovery boiler furnace in liquid state as molten smelt. In normal operation, the molten smelt is continuously extracted from the recovery boiler furnace via one or more spouts which permit the molten smelt to flow into a dissolving tank for further processing. Dynamic furnace upset conditions can result in an accumulation of solid material near the openings in the recovery boiler furnace wall, thereby preventing normal flow of the molten smelt from the recovery boiler furnace. The accumulated solid material may include solidified smelt as well as other materials, for example, but not limited to, salt cake, and / or other agglomerations.

[0031] FIG. 2 is diagram illustrating a schematic representation of an example of a recovery boiler furnace with an accumulation of solid material. As shown in FIG. 2, an accumulation of solid material 210 resulting from a furnace upset condition may form inside the recovery boiler furnace 220 of the recovery boiler. The accumulation of solid material 210 may clog the opening 255 in the wall 250 of the recovery boiler furnace 220 and may prevent molten smelt 230 from reaching the smelt spout 130 that extends through the wall 250 of the recovery boiler furnace 220 thereby preventing extraction of the molten smelt 230 from the recovery boiler furnace 220.

[0032] Conventionally, robots may be used to perform periodic scheduled maintenance such as clearing solid smelt deposits from smelt spouts external to the recovery boiler furnace. An appropriate end effector mounted on an end of a robot arm may be utilized to remove the smelt deposits from the smelt spouts without contacting the smelt spouts. However, only manual methods such as mechanical rodding and / or heating via hand-held torch are currently used to break up accumulations of solid material inside the recovery boiler furnace that block the flow of molten smelt to the smelt spouts. Aspects of the present disclosure can provide systems and methods for utilizing a robot for clearing accumulated solid material inside a recovery boiler furnace.

[0033] FIG. 3 is a diagram illustrating an example of a robot utilized for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure. As illustrated in FIG. 3, the robot 300 may be suspended from a support structure such as a gantry or platform 350 or other support structure to enable proper positioning of the robot arm 310 and end effector 320 with respect to the opening 110 (see FIG. 1) in the recovery boiler furnace wall 120 and smelt spout 130 as illustrated, for example, in FIGS. 1A, IB, 2 and 3. In some implentations, the robot 300 may be mounted to a platform disposed below the robot 300.

[0034] When utilized for unscheduled clearing of accumulated solid material inside the recovery boiler furnace, the end effector 320 used for removing smelt deposits from the smelt spouts may be replaced with an end effector configured to clear the blockage inside the recovery boiler furnace. In some implementations, the end effector 320 may be equipped with a rotary tool (not shown), for example, but not limited to, a drill, having sufficient power and a tool bit (see, e.g., FIG. 4) configured to bore one or more holes through the accumulated smelt deposit inside the recovery boiler furnace. In some implementations, the end effector 320 may be equipped with a pneumatic hammer. In some implementations, the end effector 320 used for removing smelt deposits may also be used to clear the blockage inside the recovery boiler furnace. The robot 300 may be programmed to cause the robot arm 310 to exert pressure for advancing the tool bit through the solid material deposit.

[0035] In some implementations, a tool bit 360 (see, e.g., FIG. 4) configured to bore one or more holes through the accumulated solid deposit inside the recovery boiler furnace may be attached to the end effector 320 of the robot 300. The robot 300 may be programmed to cause the robot arm 310 to provide oscillating motions while exerting pressure to advance the tool bit through the smelt deposit.

[0036] As the end effector 320 extends into the recovery boiler furnace, linear position sensors (not shown) on the robot 300 may determine the amount of extension of the end effector 320 and torque and / or force sensors (not shown) may sense when the end effector 320 has penetrated completely through the solid deposit. In some cases, the accumulated deposits inside the recovery boiler furnace may be so thick that the end effector 320 is unable to bore through before maximum extension of the end effector 320 is sensed by the linear position sensors. In suchcases, the end effector 320 may be retracted and its position, for example, its angle of entry into the opening of the recovery boiler furnace, may be adjusted and boring of the smelt deposit may be resumed. In this manner, several holes may be bored in the accumulated smelt deposit until the torque and / or force sensors sense that the end effector 320 has penetrated completely through the solid deposit.

[0037] FIG. 4 illustrates an example of a tool bit 360 that may be attached to an end effector for use with a robot for clearing accumulated solid smelt inside a recovery boiler furnace according to some aspects of the present disclosure. As illustrated in FIG. 4, the tool bit 360 may be a button-type bit such as those used in the mining industry. In some implementations, the tool bit 360 may be a tip or edge cutting bit or a bit which is consumed during the process of clearing the accumulated deposits.[00038J FIG. 5 is a diagram illustrating an example of a robot with the robot arm and end effector positioned for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure. In FIG. 5, the robot 500, the robot arm 510, and the end effector 520 may be the same as the robot 300, the robot arm 310, and the end effector 320 described with respect to FIG. 3. Referring to FIG. 5, the robot 500 may be suspended from a support structure 550. The support structure 550 may enable the robot 500 to be positioned with respect to more than one opening for the smelt spouts 535a, 535b in the wall of the recovery boiler furnace 530. In some implementations, the base of the robot 500 may be mounted to a platform disposed below the robot 500. The robot 500 may be positioned and operated by a control system.

[0039] FIGS. 8A-8C are views that illustrate a plugging device 810 and operation for the opening 110 in the furnace wall 120 that utilize a robot 800 (which may be the same as the robots 300, 500, and may be similarly mounted). The plugging device 810 includes an end effector 820 that is tapered at its distal end. The robot arm 810 is attached to an end effector 820. A plug 840 is detachably mounted on the end effector 820.

[0040] As can be seen in FIGS. 8B and 8C, the robot arm 810 can be positioned (via a gantry or the like) so that the end effector 820 with the mounted plug 840 is located adjacent to the opening 255 in the wall 250 of the boiler furnace 220 within the spout 130. The robot arm 810 is employed to insert the plug 840 into the opening 255, and then to withdraw while leaving theplug 840 in the opening 255. While this is not a particularly common operation, it may be become necessary or desirable when [INVENTORS: CAN YOU PLEASE INSERT A SHORT DESCRIPTION OF THE CIRCUMSTANCES UNDER WHICH PLUGGING BECOMES NECESSARY?] .

[0041] It may also be contemplated that a different end effector (not shown) may be employed with the robot arm 810 to remove the plug 840 at an appropriate time.

[0042] FIG. 6 is a schematic diagram illustrating an example of a control system for controlling a robot configured for clearing accumulated solid material inside a recovery boiler furnace according to some aspects of the present disclosure. The control system 600 may include a controller 610, a memory 615, a user interface (UI) 620, a robot position control 630, an arm control 640, arm position sensors 650, and linear position and / or torque / force sensors 660.

[0043] The controller 610 may be a programmable logic controller (PLC), a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device. The controller 610 may be in electrical communication with the memory 615, robot position control 630, the arm control 640, the arm position sensors 650, and the linear position / torque / force sensors 660. The controller 610 may control overall operation of the robot 500. The controller 610 may receive signals generated by various sensors including, but not limited to, the arm position sensors 650, and the linear position / torque / force sensors 660, and may perform operations on, or processing of, the signals. The controller 610 may communicate various commands, for example, but not limited to, robot position, arm control, or other commands to the robot 500.

[0044] The robot may be utilized for both smelt spout clearing and clearing accumulated solid material inside a recovery boiler furnace. A tool bit configured to clear accumulated solid material inside a recovery boiler furnace may differ from a tool bit configured for clearing a smelt spout; therefore the tool bits may be switched when utilizing the robot for the different purposes. The controller 610 may execute operator-selectable preprogrammed sequences for clearing accumulated solid material inside a recovery boiler furnace which are unscheduled and may be initiated by user input as well as preprogrammed smelt spout clearing sequences that execute automatically on a preset schedule during normal operation of the recovery boilerfurnace. In some implementations, the controller may accept operator directions that are input for individual control operations of the robot and may control the robot according to the operator-directed operation sequences.

[0045] The memory 615 may be a storage device such as a solid state storage device or other storage device and may be a combination of volatile and non-volatile storage or memory. In some implementations, portions of the memory may be included in the controller 610 to be a combination of internal and external memory. The memory 615 may be configured to store instructions executable by the controller 610 to control operation of the robot 500, as well as other applications executable by the controller 610. The memory 615 may store the preprogrammed sequences for clearing accumulated solid smelt inside a recovery boiler furnace and the preprogrammed smelt spout clearing sequences.[00046J The user interface (UI) 620 may be a touch panel or other device configured to accept manual input from a user for operating the robot 500. The user interface (UI) 620 may be provided in a location remote from the robot 500, for example, behind a safety barrier (not shown).

[0047] When clearing a blockage inside the recovery boiler furnace, an operator may initiate a preprogrammed sequence of operations via the UI 620 to cause the robot 500 to move into position at the appropriate smelt spout 535a, 535b to access the opening in the wall of the recovery boiler furnace. Alternatively, operator directions may be input for individual control operations for the robot. The robot 500 may recognize the position of the smelt spouts 535a, 535b using positioning sensors (not shown), for example, but not limited to, laser positioning sensors or other positioning sensors. Signals from the positioning sensors may be provided to the controller 610 and the controller 610 may communicate commands to the robot position control 630 to provide coarse positioning of the robot 500 at a particular smelt spout 535a, 535b.

[0048] The trajectory of the end effector (e.g. the end effector 320, 520) for clearing accumulated solid smelt inside a recovery boiler furnace may be controlled by an operator- selectable preprogrammed sequence. The robot can exactly control position and direction of the end effector such that the end effector is not guided by contact with the smelt spout. The noncontact guidance can prevent damage to the recovery boiler furnace.

[0049] The arm control 640 may receive commands from the controller 610 and may set the end effector at a predetermined angle, for example 10° from horizontal or another angle, to enter the opening in the recovery boiler furnace (e.g., the opening 110 illustrated in FIG. 1). Arm position sensors 650 may provide robot arm position information to the controller 610. The robot arm (e.g., the robot arm 310, 510) may advance the end effector into the recovery boiler furnace through the opening at the predetermined angle to clear the blockage inside the recovery boiler furnace. The linear position / torque / force sensors 660 may provide position and / or torque and / or force information about the position of the end effector and torque and / or force applied to the end effector to the controller 610. The controller 610 may determine the insertion depth of the end effector inside the recovery boiler furnace and may determine whether the end effector has penetrated through the blockage based on torque and / or force information received from the linear position / torque / force sensors 660. For example, the controller 610 may determine that the end effector has penetrated through the blockage based on the signals provided by the linear position / torque / force sensors 660 indicating that the end effector has not reached maximum extension but the torque and / or force applied to the end effector has decreased.

[0050] When the controller 610 determines that the linear position information received from the linear position / torque / force sensors 660 indicates a maximum end effector insertion depth, for example, 3 feet or another insertion depth, of the end effector past the wall of the recovery boiler furnace into the recovery boiler furnace and the torque information received from the linear position / torque / force sensors 660 indicates that the end effector has not penetrated through the blockage, the preprogrammed sequence may cause the controller 610 to command the arm control 640 to the retract the end effector.

[0051] An operator-selectable preprogrammed sequence or operator-directed operation sequence may cause the controller 610 to communicate commands to the arm control 640 to change the entry angle of the end effector into the opening of the recovery boiler furnace, for example, from 10° to 15° from horizontal and cause the arm control 640 to advance the end effector into the recovery boiler furnace at the new angle. If the blockage is not cleared, e.g., if liquid smelt does not begin to flow in the smelt spout, the sequence may be repeated until the controller 610 determines that the end effector has penetrated through the blockage inside the recovery boiler furnace, for example, as indicated by a reduction of torque sensed by the linearposition / torque / force sensors 660. In this manner, multiple holes may be bored at different angles in the accumulated material deposit inside the recovery boiler furnace until the blockage is cleared. Liquid smelt flow may also be determined visually by, for example, but not limited to, operator observation of the smelt spout, video camera, etc.

[0052] In some implementations, each time the end effector is retracted without boring through the blockage, a different operator-selectable preprogrammed sequence may be selected by an operator to change the entry angle and bore an additional hole. In some implementations, the sequence of setting an initial entry angle of the end effector, boring a hole into the blockage, retracting the end effector, changing the entry angle, and boring additional holes in the blockage may be automatically performed as part of the currently executing preprogrammed sequence. In some implementations, the insertion depth and / or torque and / or force settings for the end effector that indicate breakthrough of the blockage may be set by an operator.

[0053] FIG. 7 is a flowchart illustrating an example of a method 700 for controlling a robot for clearing a blockage inside a recovery boiler furnace according to some aspects of the present disclosure. Referring to FIG. 7, at block 710, the robot may move into position to access an opening in the recovery boiler furnace wall. An operator may initiate a preprogrammed sequence of operations via a user interface to cause the robot to move into position at the appropriate smelt spout to access the opening in the wall of the recovery boiler furnace. In some implementations, operator directions may be input for individual control operations of the robot. The robot may recognize the position of the smelt spouts using positioning sensors, for example, but not limited to, laser positioning sensors or other positioning sensors. Signals from the positioning sensors may be provided to a controller to provide coarse positioning of the robot at a particular smelt spout.

[0054] At block 715, the robot may be operated to position the end effector at an opening in the recovery boiler furnace wall. The trajectory of the end effector for clearing accumulated solid material inside a recovery boiler furnace may be controlled by a preprogrammed sequence. The robot can exactly control position and direction of the end effector such that the end effector is not guided by contact with the smelt spout. The robot (e.g. the arm control) may receive commands from the controller and may set the end effector at a predetermined angle, forexample 10° from horizontal or another angle, to enter the opening in the recovery boiler furnace.

[0055] At block 720, it may be determined whether the end effector is a rotary tool or pneumatic hammer. In some implementations, the end effector may be equipped with a rotary tool, for example, but not limited to, a drill, having sufficient power and a tool bit. In some implementations, a tool bit may be attached to the end effector the robot arm may provide oscillating motions while exerting pressure to advance the tool bit through the smelt deposit. In some implementations, the end effector may be a pneumatic hammer.

[0056] In response to determining that the end effector is a rotary tool or pneumatic hammer (720 -Y), at block 725, a drive for the rotary tool for pneumatic hammer may be engaged to start operation of the rotary tool or pneumatic hammer and the process may continue at block 730.

[0057] In response to determining that the end effector is not a rotary tool or pneumatic hammer (720 -N), the process may continue at block 730.

[0058] At block 730, the robot may be operated to perform operator-selectable preprogrammed sequences of operations to clear a blockage inside the recovery boiler furnace. Alternatively, operator directions may be input for individual control operations of the robot. Arm position sensors may provide robot arm position information to the controller. The robot arm may advance the end effector into the recovery boiler furnace through the opening at the predetermined angle to clear the blockage inside the recovery boiler furnace.

[0059] At block 735, it may be determined whether a maximum insertion depth of the end effector has been reached. The controller may determine whether linear position information received from the linear position sensor indicates a maximum insertion depth of the end effector has been reached.

[0060] In response to determining that the maximum insertion depth of the end effector has been reached (735 -Y), at block 740, the controller may cause the robot to retract the end effector from the opening in the recovery boiler furnace wall.

[0061] At block 745, the position of the end effector may be changed. In some implementations, an operator may select a different operator-selectable preprogrammed sequenceto change the entry angle for the end effector and the process may continue at block 730. In some implementations, the currently executing preprogrammed sequence may automatically change the entry angle for the end effector and the process may continue at block 730.

[0062] In response to determining that the maximum insertion depth of the end effector has not been reached (735 -N), at block 750, it may be determined whether the blockage inside the recovery boiler furnace has been cleared. The controller may determine that the end effector has penetrated through the blockage inside the recovery boiler furnace, for example, as indicated by a reduction of torque and / or force sensed by the torque / force sensor as the end effector penetrates through the blockage.

[0063] In response to determining that the blockage inside the recovery boiler furnace has been cleared (450-Y), at block 755, the end effector may be retracted and the process ends.

[0064] In response to determining that the blockage inside the recovery boiler furnace has not been cleared (750-N), the process may continue at block 730.

[0065] The specific operations illustrated in FIG. 7 provide a particular method for controlling a robot for clearing a blockage inside a recovery boiler furnace according to an embodiment of the present disclosure. Other sequences of operations may also be performed according to alternative embodiments. For example, alternative embodiments of the present disclosure may perform the operations outlined above in a different order. Moreover, the individual operations illustrated in FIG. 7 may include multiple sub-operations that may be performed in various sequences as appropriate to the individual operation. Furthermore, additional operations may be added or removed depending on the particular applications.

[0066] The method 700, may be embodied on a non-transitory computer readable medium, for example, but not limited to, the memory 615 or other non-transitory computer readable medium known to those of skill in the art, having stored therein a program including computer executable instructions for making a controller, processor, computer, or other programmable device execute the operations of the methods.

[0067] Referring now to FIG. 9, a system for operatorless servicing of a boiler furnace is shown therein and designated broadly at 900. The system 900 includes a robot arm 905 and a plurality of end effectors (one of which is shown herein at 910). Each of the end effectors 910 isconfigured to perform a service operation of the group consisting of clearing an opening in a wall of the boiler furnace at least partially closed with solid smelt; collecting a sample of solid smelt from the opening; plugging the opening with a plug; and removing the plug from the opening. Each of these service operations may be carried out in the manner described above, with the appropriate end effector 910 being attached to the robot arm 905. In addition, the system includes a control system 920 that is configured to execute one or more preprogrammed sequences of operations for controlling the robot arm 905 to operate two of the end effectors 910 to complete at least two of the service operations. For example, in the illustrated embodiment, the programmed sequences for clearing an opening, collecting a sample of solid smelt from the opening, plugging the opening, and removing the plug from the opening are included and are designated in FIG. 9 at, respectively, 930, 940, 950, and 960. However, in some embodiments only two or three of these service operations may be included, or additional services operations may be included in other embodiments. The structure and operation of the control system 920 and the programmed sequences 930, 940, 950, 960 may be as set forth above and need not be described in detail herein.

[0068] The system 900 as described above can provide a boiler furnace with operatorless servicing of the spouts and the surrounding areas; that is, service operations that present some degree of physical risk to an operator can be performed by the system 900, threby avoiding the need for human intervention during these operations. As a result, the level of safety associated with servicing the boiler furnace can increase significantly.

[0069] Those skilled in this art will also recognize that other features and functions may be included in an operatorless system. For example, the system may include a module with the capability of sensing unwanted movement / presence (e.g., a person) in the vicinity of the spout and robot. The module may rely on a still or video camera, one or more motion detectors, light detectors, or other presence-sensing devices. The module may also include an alarm operatively connected with the presence-sensing device to alert a monitor to the presence of an unwanted visitor. The system may also include a switch or the like that causes any other operations (e.g., clearing, sampling, etc.) to cease if unwanted presence is detected at or near the spout.

[0070] Presence sensing modules of the type described above may take many forms. Exemplary modules include those available from Intenseye (Intenseye Platform), Rockwell (Allen Bradley presence-sensing devices) and others.

[0071] The examples and embodiments described herein are for illustrative purposes only. Various modifications or changes in light thereof will be apparent to persons skilled in the art. These are to be included within the spirit and purview of this application, and the scope of the appended claims, which follow.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A system for clearing an accumulated material deposit inside a furnace, the system comprising: a robot having an end effector configured to clear the accumulated material deposit inside the furnace; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate the end effector.

2. The system of claim 1, wherein the end effector comprises a tool bit coupled to the end effector and configured to penetrate the accumulated material deposit inside the furnace.

3. The system of claim 2, wherein the robot is controlled to cause an oscillating motion of the end effector and tool bit.

4. The system of claim 1, wherein the end effector comprises a rotary tool.

5. The system of claim 4, further comprising a tool bit coupled to the rotary tool and configured to penetrate the accumulated material deposit inside the furnace.

6. The system of claim 5, wherein the rotary tool provides rotational motion to the tool bit to bore through the accumulated material deposit inside the furnace.

7. The system of claim 1, wherein the control system comprises: a controller configured to communicate commands to the robot; and a plurality of sensors disposed on the robot, wherein the sensors are configured to sense a position of the end effector and torque or force applied to the end effector.

8. The system of claim 7, wherein the controller is configured to execute an operator initiated sequence of instructions to control the robot to clear the accumulated material deposit inside the furnace.

9. The system of claim 7, wherein the controller is configured to control the robot based on signals received from the plurality of sensors such that the end effector does not contact a smelt spout or a wall of the furnace.

10. The system of claim 7, wherein the control system further comprises a memory, wherein the memory is configured to store a plurality of operator-selectable preprogrammed sequences for clear the accumulated material deposit inside the furnace, wherein the operator-selectable preprogrammed sequences specify different end effector angles for accessing an opening in a wall of the furnace.

11. A robot for clearing an accumulated material deposit inside a furnace, the robot comprising: an end effector configured to clear the accumulated material deposit inside the furnace; a robot arm coupled to the end effector and configured to control a position of the end effector; a tool bit coupled to the end effector; and a plurality of sensors configured to sense a position of the end effector and torque or force applied to the end effector, wherein the end effector and the tool bit are configured to penetrate the accumulated material deposit inside the furnace.

12. The robot of claim 11, wherein the robot arm is controlled to cause an oscillating motion of the end effector and tool bit.

13. The robot of claim 11, wherein the end effector comprises a rotary tool coupled to the robot arm.

14. The robot of claim 13, further comprising a tool bit coupled to the rotary tool and configured to penetrate the accumulated material deposit inside the furnace.

15. The robot of claim 14, wherein the rotary tool provides rotational motion to the tool bit to bore through the accumulated material deposit inside the furnace.

16. The robot of claim 11, wherein the plurality of sensors is configured to generate end effector position signals utilized to maintain non-contact operation of the end effector with respect to a smelt spout and a wall of the furnace.

17. A method for clearing accumulated material deposits inside a furnace, the method comprising initiating a preprogrammed sequence to: position a robot to access an opening in a wall of the furnace; position an end effector of the robot at a specified angle for accessing the opening; operate the robot to cause the end effector to breakthrough the accumulated material deposits; and retract the end effector.

18. The method of claim 17, further comprising: determining that the end effector has reached a maximum insertion depth in the furnace; in response to determining that the end effector has reached a maximum insertion depth in the furnace: retracting the end effector; selecting a different preprogrammed sequence to change an angle at which the end effector will enter the opening in the wall of the furnace; and operating the robot at the changed angle to cause the end effector to breakthrough the accumulated material deposits.

19. The method of claim 17, further comprising: determining that a tool bit is coupled to the end effector; and in response to determining that the tool bit is coupled to the end effector, controlling the robot to cause an oscillating motion of the end effector and tool bit.

20. The method of claim 17 further comprising: determining that a rotary tool is coupled to the end effector; andin response to determining that the rotary tool is coupled to the end effector, engaging a drive of the rotary tool to provide rotational motion to a tool bit coupled to the rotary tool.

21. A system for inserting a plug in an opening in a wall of a boiler furnace: a robot having an end effector configured to mount a plug sized to plug the opening; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate the end effector.

22. A system for operatorless servicing of a boiler furnace, comprising: a robot having a robot arm and one of a plurality of end effectors, each of the plurality of end effectors being configured to perform a service operation of the group consisting of: clearing an opening in a wall of the boiler furnace at least partially closed with solid smelt; collecting a sample of solid smelt from the opening; plugging the opening with a plug; and removing the plug from the opening; and a control system configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate two of the end effectors to complete at least two of the service operations.

23. The system defined in Claim 22, wherein the controller is configured to execute one or more preprogrammed sequences of operations for controlling the robot to operate perform at least three of service operations.

24. The system defined in Claim 22, wherein the at least two service operations are performed without human intervention at the wall of the boiler furnace.

25. The system defined in Claim 22, further comprising a presence-sensing module operatively connected with the controller configured to detect the presence of an unwanted visitor near the opening of the wall of the boiler furnace.

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