Patent Application
20100206333
The present application relates to a method for remotely cleaning a radiant boiler of a furnace.
The Kevcit smelter is a slag furnace used in the recovery of zinc and co-products from the slag. Referring to
The bullion continues to settle through the molten slag layer beneath the coke checker. Together with the zinc-bearing iron slag, the bullion passes under a partition wall into a compartment, which is an electric furnace. This partition wall extends into the molten slag forcing the hot sulphur dioxide gas to pass through a waste heat boiler and onto an electrostatic precipitator rather than into the electric furnace compartment
The metallic slag 12 containing all of the iron and most of the zinc from a Kivcet Furnace, is transferred in 70 tonne batches to a coal-fired fuming furnace (not shown). To recover the zinc, fine coal and air are injected one metre below the top of the slag bath. The heat generated causes the zinc to fume as a vapour from the furnace bath and is immediately reoxidized by tertiary air above the bath to form zinc oxide fume. These fumes and hot gases are cooled in a waste heat boiler 14 before passing through a baghouse to collect the zinc fumes for treatment in an adjacent Fume Leach Plant (not shown). The waste heat boiler 14, see
Traditionally, men clad only with masks, gloves and work clothes entered the room after it had been shut down and cooled and manually cleaned off the deposits. Considering that some of the deposits include thallium, arsenic and other deadly contaminants, any accidental contact with the skin could be fatal. Consequently, a method of cleaning the waste boiler is needed which minimizes human contact.
According to the invention there is provided a method and apparatus for directing high pressure fluid against a substantially vertical surface for the purpose of cleaning or scarifying the surface. The surface may be, for instance, a wall, or cooling pipes, plates, or other structures attached to a wall. Such surfaces include, by way of example, the wall of a cooling tower and vertical cooling pipes of a radiant boiler of a Kivcet furnace. The term “surface” is used herein to refer to any structures to which high pressure fluid can be effectively and advantageously applied.
The apparatus comprises a robot suspended from cables adjacent to the surface and operable to move back and forth across the surface area. The robot comprises one or more nozzles in communication with a source of high-pressure fluid, normally water. As the robot moves back and forth across the surface, a high-pressure jet of fluid is emitted from the nozzles against the surface, producing a substantially horizontal swath of cleaned or scarified surface. The apparatus also comprises means for raising and lowering the robot along the surface. When a first swath has been completed, the robot is raised or lowered and a subsequent swath is produced in a like manner as the first. The apparatus is then moved to another uncleaned wall of the waste boiler and cleans or scarifies that wall. The waste water and removed material produced by the operation is collected and transferred to a waste tank. The word “cleans or cleaning” is used herein to include scarifying a surface and removing deposits built up on a surface.
The method of the invention includes a mounting step by which a pair of cables is suspended vertically adjacent the surface. Ends of t the robot are attached to respective ones of the cables , the robot being moveable up and down the surface either by crawling along the cables or by means of the cables being raised and lowered.
The robot may comprise an elongated rail suspended at either end from the cables. A carriage containing at least one nozzle is mounted on the rail, with the carriage being moveable back and forth along the rail. A high pressure water line is coupled to the nozzle so that the nozzle is operative to emit a jet of water against the surface when the water line is opened, thereby producing a swath cleaned surface as the nozzle is moved to and fro across the surface. The rail is repeatedly moved up or down the surface along the cables, and the carriage is moved back and forth on the rail, thus cleaning the wall from top to bottom or for bottom to top. The foregoing steps are repeated for each remaining uncleaned wall.
The cable is optionally wound on drums, the drums being rotatable in response to control signals from a user.
The cables are optionally attached by its upper end to a fixed point and the rail ends are attached to the cables by a gear system that allows the rail to crawl up and down the cable.
In one embodiment of the invention there is provided a method of cleaning a waste boiler of a Kivcet furnace, which method comprises suspending a pair of spaced apart cables down from a roof of the waste boiler, adjacent an interior surface to be cleaned, attaching ends of the rail to respective ones of the cables with equal lengths of cable between the rail and the roof, the rail being reversibly moveable up and down the wall. A carriage with a pair of nozzles, one above another on the rail, is reversibly moved along the rail. High-pressure water lines are coupled to the nozzles, with the nozzles operative to emit jets of water against the surface when the water lines are opened. The rail is moved from one of a top and bottom of the surface to another of the top and bottom of the surface, and the carriage is moved from one side of the rail to the other, cleaning the surface as it moves. The foregoing steps are repeated for each remaining uncleaned surface.
Advantageously, the cable is wound on drums supported by the boiler roof and the drums are rotatable in response to control signals from a user. The cable may be affixed to the roof and attached to a gear system at the rail which allows the rail to crawl up and down the cable. Preferably, the rail commences operation at a top of the wall and moves downwardly.
A lower pressure may be applied to the surface first and a great pressure next. In the case of the rail commencing operation at a top of the wall, the ultra high pressure nozzle is on the top and the high pressure nozzle is below. A waste line is coupled at one end to a floor of the waste boiler and at another end to a waste tank and is operative to drain waste from the waste boiler to the waste tank.
Further features and advantages will be apparent from the following detailed description, given by way of example, of a preferred embodiment taken in conjunction with the accompanying drawings, wherein:
In the following high pressure water jetting shall mean cleaning performed at pressures between 10,000 to 25,000 psi while ultra high pressure water jetting shall mean cleaning performed at pressures greater than 25,000 psi.
As shown in
Once the waste storage tank 20 has been connected, the cleaning robot is set up as seen in
A carriage 44 consisting of a mounting plate and three rail engaging wheels 46 moves from one side of rail 34 to the other, powered by a motor (not shown). Mounted on a mounting plate 71 are two vertically spaced apart nozzles 40 and 42. Two separate water pressure systems are coupled to nozzles 40 and 42. A 20,000 psi source of water is coupled to nozzle 40 and a 40,000 psi line is coupled to nozzle 42. In order to simplify the drawing no hoses or electrical components have been shown.
Drums 30 and 32 each have motors with remotely operated controllers coupled to a user control (not shown). By rotating drums 30 and 32 in the appropriate direction the robot 70 can be raised or lowered along the surface. A fixed connection to cables 24 and 26 can be replaced with a remotely controlled cable gripping gear system that allows the rail 34 to crawl up and down cables 24 and 26.
One or more ancillary water hoses 54 and 56 are attached to the robot 70, preferably at blocks 36 and 38, respectively. The ancillary water hoses have push nozzles 50 and 52 that emit jets of water in the opposite direction from the surface 18. When high pressure water is forced through the push nozzles 50 and 52, the momentum of the water emitted from nozzles 40 and 42 is counteracted to prevent the robot from being moved away from the surface.
In operation, using the embodiment shown in
As shown in
When one surface has been cleaned, the room is dried and the cleaned apparatus moved to an adjacent surface and the process is repeated, until all four surfaces have been cleaned. It is possible to start at a bottom of a wall and progress upwardly but all of the removed material would drop down on the rail and other parts of the cleaned apparatus. It is also possible to operate two or more rail assemblies 35 on two or more surfaces at the same time to speed up the cleaning process. The purpose of the ultra high pressure being applied to nozzle 42, is to smoothen out the surface and to blow away any residue left on the surface by operation of nozzle 40.
Referring to
While the method has described sequential cleaning of adjacent surfaces, as mentioned above, it is possible to clean more than one surface at a time by employing multiple robots simultaneously. Ancillary water lines 54 and 56 and associated push nozzles 50 and 52 provide a rearwardly thrust that counteracts the thrust from the water emitted from nozzles 40 and 42.
Accordingly, while this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2601493 | Sep 2007 | CA | national |
| 2605826 | Oct 2007 | CA | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2008/001432 | 8/6/2008 | WO | 00 | 3/9/2010 |
