Components of a descaling chamber and a descaling method

Abstract

A method of descaling sheet metal includes first and second descaling components, each having a single motor-driven slurry propelling impeller mounted to the top and bottom of a housing, the top and bottom mounted impellers of the first component configured to urge slurry against the sheet metal passing through the housing in a first direction extending from one side of the housing to an opposite side and across the entire width of the sheet metal, and the top and bottom mounted impellers of the second component configured to urge slurry against the sheet metal passing through the housing in a second direction opposite the first direction and extending from the opposite side of the housing to one side and across the entire width of the sheet metal.

Description

[Technical Field]

[0001] This application claims the benefit of U.S. Non-Provisional Patent Application No. 17 / 316,884, filed May 11, 2021, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The present disclosure is directed to descaling chamber components that improve upon descaling chamber designs and their methods of use described in other commonly owned patents, including U.S. Patent Nos. 7,601,226, 8,062,095, 8,066,549, 8,074,331, and 8,128,460, the disclosures of which are incorporated herein by reference in their entirety. As will become apparent from the disclosure below, this descaling chamber provides a more standard platform for descaling chambers that improves quality, reduces operating and maintenance costs, and is simpler in construction and less expensive to manufacture. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 7,601,226 [Patent Document 2] U.S. Patent No. 8,062,095 [Patent Document 3] U.S. Patent No. 8,066,549 [Patent Document 4] U.S. Patent No. 8,074,331 [Patent Document 5] U.S. Patent No. 8,128,460 [Brief explanation of the drawings]

[0004] [Figure 1] FIG. 2 is a partial front-end view of a processing line using an exemplary descaling component. [Figure 2] FIG. 2 is a partial view of the rear end of a processing line using an exemplary descaling component. [Figure 3] 3 is an enlarged detail view of area 3-3 of FIG. 2 showing exemplary descaling components in the processing line from the drive side of the processing line. [Figure 4] 4 shows the descaling components of FIG. 3 viewed from the opposite side of FIG. 3, from the opposite side of the drive side of the processing line. [Figure 5] FIG. 4 is a plan view of the descaling component of FIG. 3. [Figure 6] 4 is a plan view of one of the descaling components of FIG. 3 with the top and top-mounted impeller and motor removed to show the rinsing station and the interior of the descaling component housing. [Figure 7] FIG. 1 shows the front end of the first of a series of descaling components in a processing line. [Figure 8] FIG. 1 shows the rear end of the next in a series of descaling components in a processing line. [Figure 9] FIG. 1 is a perspective view of the first in a series of descaling components of a processing line showing the floor of the processing line and the holes in the equipment. [Figure 10] FIG. 1 is a perspective view of the first in a series of descaling components of a processing line, with holes in the floor and equipment removed to provide further detail of the descaling component's pumps, abrasive particle valves, and eductors. [Figure 11] 11 is an opposite perspective view of FIG. 10 showing the first in a series of descaling components of a processing line with holes in the floor and equipment removed to provide further detail of the descaling components' pumps, abrasive particle valves, and eductors. [Figure 12] FIG. 1 shows the front end of the first in a series of descaling components of a processing line with holes in the floor and equipment removed to provide further detail of the descaling component's pumps, abrasive particle valves, and eductors. [Figure 13] FIG. 6 is a schematic diagram of a blast pattern for the first in a series of descaling components, such as that shown in FIG. 5. [Figure 14] FIG. 6 is a schematic diagram of a blast pattern for the next in a series of descaling components, such as that shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0005] 1 and 2 illustrate an exemplary processing line 20. FIG. 1 illustrates the front end of the processing line, and FIG. 2 illustrates the rear end of the processing line, with descaling components 22 included in detail area 3-3 in FIG. 2. A coil 24 of pre-processed sheet metal (e.g., hot-rolled steel) is positioned adjacent to the processing line 20 to supply an elongate length of sheet metal 26 to the remainder of the processing line. The coil 24 of sheet metal may be supported by any conventional uncoiler 28, which functions to selectively unwind the elongate length of sheet metal 26 from the coil in a controlled manner. Although not shown, the sheet metal may alternatively be supplied to the processing line as individual sheets. The free end of the sheet metal 26 from the uncoiler 28 may be directed to a crop shear 30 to shear the free, stripped end of the coil perpendicular to the elongate edge of the strip, allowing the strip to be efficiently threaded through the line. The sheet metal 26 may then be guided through a scale breaker 32 and a roller straightener 34. Pinch rollers 36 may pull the sheet metal 26 through the scale breaker 32 and push the strip through the roller straightener 34. Depending on the material size to be processed on the processing line, the line may be equipped with a stitching machine 38 to connect successive stretches of material together. For example, if the processing line is intended to process very thin gauge sheet metal, the free ends of the strip from a continuous coil may be stitched together using a stitching machine, allowing the thin gauge material to be pulled through the processing line. The thin gauge material may distort excessively when pushed through the processing line, necessitating the use of a tension reel to pull the material through the processing line. The stitcher may comprise a welder. The stitching machine may be omitted. Along with the stitching machine 38, the line may be equipped with an edge trimmer 40 to allow the successive ends of the continuous coil to be neatly joined. To complete the descaling process, the processing line may be provided with two descaling components 22, as will be explained in more detail below.The descaling media may include a slurry of abrasive particles and a liquid. The descaling media may also include abrasive particles. After the sheet metal 26 passes through the descaling component 22, it may pass through a drying table 42, a crop shear 44, and onto a take-up reel 46. The take-up reel may include a recoiler, such as that described in U.S. Pat. No. 8,707,529, the disclosure of which is incorporated herein by reference.

[0006] As noted, the processing line includes a pair of descaling elements 22 aligned in series to remove scales from the top and bottom surfaces of the sheet metal 26. The pair of descaling elements is arranged sequentially downstream in the sheet metal travel direction 48. Both descaling elements are similarly constructed, except that in one descaling element, a single slurry propelling impeller wheel 50A, 50B is positioned adjacent to one side of the sheet metal being processed (e.g., the operator side of the processing line), and in the other descaling element, a single slurry propelling impeller wheel is positioned adjacent to the opposite side of the sheet metal being processed (e.g., the drive side of the processing line). Applicant has determined that two descaling elements arranged in this manner provide greater efficiency than the eight slurry impeller wheels in the descaling chamber described in the prior patent, and that the line speed, scale removal, and surface texture of the processed sheet metal are equivalent to those of the eight slurry impeller wheels in the descaling chamber described in the prior patent.

[0007] 3 and 4 are enlarged side views of the descaling component 22 removed from the processing line. In FIG. 3, the direction of travel 48 of the elongated sheet metal is from left to right. The descaling component includes a hollow housing 52. A portion of the elongated sheet metal is shown passing through the descaling component housing. The elongated sheet metal 26 is shown oriented generally horizontally as it passes through the descaling component housing or box. It should be understood that the horizontal orientation of the sheet metal shown in the figures is one way of advancing the sheet metal through the descaling chamber; the sheet metal may be oriented vertically or in any other direction as it passes through the descaling component apparatus. Therefore, terms such as "top" and "bottom," "upper" and "lower," and "upper" and "lower" should not be construed as limiting the orientation of the apparatus or the relative orientation of the elongated sheet metal, but should be construed to refer to the orientation of the elements shown in the figures for illustrative purposes.

[0008] The upstream or front end 54 of the housing (see FIG. 7) has a narrow entrance 56 opening slot to accommodate the width and thickness of the sheet metal 26 of a certain extent. The opposite downstream or rear end 58 of the housing (FIG. 8) has a narrow slotted exit opening 60, also sized to accommodate the width and thickness of the sheet metal 26 of a certain extent. These openings are equipped with sealing devices designed to contain the slurry within the housing or box during sheet metal processing. The descaling component housing 52 also has a top 62, a bottom 64, and first and second sides 66, 68, which define the interior of the housing. The bottom 64 of the housing is formed with a discharge chute 70 that communicates with the interior of the housing. The discharge chute 70 allows for the discharge of material removed from the sheet metal 26 of a certain extent and the accumulation of used slurry from the interior of the housing 52. As will be explained, the relative size of the descaling component herein is reduced compared to the descaling components described in the applicant's previous patents. Accordingly, it no longer includes the containment support devices used in prior art descaling components to assist in threading the strip ends through the machine, and the interior of the housing 52 therefore remains essentially open, except for an optional rinse station (see FIG. 6) which may be provided adjacent the housing outlet opening 60.

[0009] Each descaling element 22 is provided with a single motor-driven slurry-propelling impeller 50A mounted on the top 62 of the housing 52. Depending on the position of the descaling elements 22 in the processing line, the first descaling element in the series will have a single motor-driven impeller 50A mounted on the top 62 of the housing 52 adjacent one side 66 of the housing, and the next descaling element in the series will have a single motor-driven impeller mounted on the top of the housing adjacent the opposite side 68 of the housing. For example, the first descaling element in the series will have a single motor-driven impeller 50A mounted on the top 62 of the housing 52 on the operator side of the housing, and the next descaling element in the series will have a single motor-driven impeller mounted on the top of the housing on the drive side of the housing. Although not shown, the reverse orientation is also possible. Each top motor-driven slurry propelling impeller 50A is adapted and configured to urge slurry 72 onto the top surface of the sheet metal 26 within the housing 52, across the entire width 74 of the sheet metal in a direction extending from one side 66 to the opposite side 68 of the sheet metal passing within the housing.

[0010] Each descaling component is also provided with a single motor-driven slurry-propelling impeller 50B mounted on the bottom 64 of the housing 52. Depending on the location of the descaling components in the processing line, the first descaling component in the series will have a single bottom motor-driven impeller 50B mounted on the bottom 64 of the housing 52 adjacent one side 66 of the housing, and the next descaling component in the series will have a single bottom motor-driven impeller 50B mounted on the bottom 64 of the housing 52 adjacent the opposite side 68 of the housing. For example, the first descaling component in the series will have a single bottom motor-driven impeller 50B mounted on the bottom 64 of the housing 52 on the operator side of the housing, and the next descaling component in the series will have a single bottom motor-driven impeller 50B mounted on the bottom of the housing on the drive side of the housing. Although not shown, the reverse orientation is also possible. A single motor-driven slurry propelling impeller 50B at the bottom is adapted and configured to urge slurry 72 within the housing 52 onto the bottom surface of the sheet metal across the entire width 74 of the sheet metal.

[0011] For each descaling element 22, the single motor-driven slurry propelling impeller 50B at the bottom can urge slurry 72 against the bottom surface of the sheet metal 26 across the entire width 74 of the sheet metal in the same direction as the single motor-driven slurry propelling impeller 50A at the top, within the housing interior. For example, as shown in FIG. 13, the first in the series of descaling elements can be positioned so that the single motor-driven impellers 50A, 50B at both the top and bottom urge slurry against the sheet metal passing through the housing interior in a direction extending from one side 66 of the housing to the opposite side 68 of the housing. As shown in FIG. 14, the next in the series of descaling elements can be positioned so that the single motor-driven impellers 50A, 50B at both the top and bottom urge slurry against the sheet metal passing through the housing interior in a direction extending from the opposite side 68 of the housing to the one side 66 of the housing. In this way, the forces exerted by the blast patterns of the single motor-driven slurry propelling impeller 50A at the top and the single motor-driven slurry propelling impeller 50B at the bottom of each descaling component 22 can be balanced across the sheet metal 26 passing through each descaling component.

[0012] As between adjacently positioned descaling components 22, the single motor-driven slurry propelling impeller 50A at the top of the first in the series of descaling components is adapted and configured to urge slurry 72 against the sheet metal 26 passing within the housing in a direction extending from the first side 66 of the housing 52 toward the second side 68 of the housing. The single motor-driven slurry propelling impeller 50A at the top of the next in the series of descaling components is adapted and configured to urge slurry 72 against the sheet metal 26 passing within the housing in a direction extending from the second side 62 of the housing 52 toward the first side 66 of the housing. In this manner, the blast pattern from the single motor-driven slurry impeller 50A at the top of the first descaling element in the series complements the blast pattern from the single motor-driven slurry impeller at the top of the next descaling element in the series to cumulatively provide a uniform blast pattern across the entire width 74 of the sheet metal passing through the processing line. In the same manner, the single motor-driven slurry impeller 50B at the bottom of the first descaling element in the series is adapted and configured to urge slurry 72 within the housing 52 in a direction extending from the first side 66 of the housing 52 toward the second side 68 of the housing and onto the sheet metal 26 passing through the respective housing interior. The single motor-driven slurry impeller 50B at the bottom of the next descaling element in the series is adapted and configured to urge slurry 72 within the housing 52 in a direction extending from the second side 68 of the housing 52 toward the first side 66 of the housing and onto the sheet metal 26 passing through the respective housing interior. In this manner, the blast pattern from the single motor-driven slurry propelling impeller 50B at the bottom of the first in the series of descaling elements complements the blast pattern from the single motor-driven slurry propelling impeller 50B at the bottom of the next in the series of descaling elements to cumulatively provide a uniform blast pattern across the entire width of the sheet metal passing through the processing line.

[0013] The impeller wheels 50A, 50B of each descaling element are configured so that the contact area of ​​the slurry urged by each descaling wheel extends entirely across and slightly beyond the width 74 of the sheet metal for a certain extent. Allowing the impeller wheel discharge to extend slightly beyond the edge of the strip ensures mostly uniform coverage. Because the direction of travel of the slurry urged by the impeller wheel relative to the width 74 of the sheet metal varies with the position of the slurry discharge across the impeller wheel diameter, there may be some directionality to the resulting texture for the location of the slurry impinging furthest from the wheel. This may be complemented by the corresponding (i.e., top or bottom) impeller wheel of the next descaling element in the series. The corresponding impeller wheel of the next descaling element in the series may also rotate in the opposite direction to the corresponding impeller wheel of the first descaling element in the series. The impact density of the slurry on the sheet metal being processed will be greater in areas located closer to the impeller wheel, and will decrease as one moves progressively across the sheet metal. Furthermore, by aligning the impeller wheel of the first descaling element in the series with one side of the sheet metal and the corresponding (i.e., top or bottom) impeller wheel of the next descaling element in the series with the opposite side of the sheet metal, and rotating these impeller wheels in opposite directions, if applicable, a side-by-side, mirror-image slurry impact density pattern will be produced across the width of the sheet metal, thereby resulting in a uniform blast pattern across the width of the material.

[0014] Additionally, a single motor-driven impeller at either or both the top and bottom can be adjustably positioned toward and away from the surface of the sheet metal passing through the descaling component. This provides a secondary adjustment for use with sheet metal of different widths. By moving the impeller away from the surface of the sheet metal, the width of the impact area at the surface of the sheet metal can be increased. By moving the impeller toward the surface of the sheet metal, the width of the impact area at the surface of the sheet metal can be decreased. This adjustable positioning of the impeller allows the descaling component to remove scale from sheet metal of different widths. An additional method for adjusting the width of the area where the slurry impacts the surface of the sheet metal is to move the angular position of the inlet nozzle relative to the impeller casing / shroud. A third option is to rotate the impeller about an axis perpendicular to the axis of rotation relative to the direction of sheet metal travel, so that the oval area of ​​slurry impact from each wheel will not be square or transverse to the direction of sheet metal travel, even if it remains the same extension. Movement away from and towards the strip also changes the impact energy of the flow, which in turn changes the effectiveness of descaling and surface conditioning to produce rust-inhibiting materials.

[0015] Additionally, the angular orientation of the descaling wheel axis also directs the slurry impingement at an angle relative to the sheet metal surface. The angle of impact of the slurry with the sheet metal surface is selected to optimize the effectiveness of descaling and surface conditioning to produce a rust-inhibiting material. An angle of 15° has been found to be satisfactory.

[0016] Each motor-driven slurry propulsion impeller 50A, 50B is mounted in a line-up casing, shroud, or cowling that is attached to the descaling component's housing structure, such as the housing's top wall 62 or bottom wall 64, as applicable. The shroud has a hollow interior that communicates with the housing's interior through an opening in the housing structure. An electric motor is provided for each of the single motor-driven slurry propulsion impeller 50A at the top and the single motor-driven slurry propulsion impeller 50B at the bottom. Each electric motor is attached to the respective top 62 and bottom 64 of the shroud and / or housing 52. The electric motor has an output shaft that extends through the wall of the associated shroud and into the interior of the shroud. Each impeller wheel 50A, 50B is attached to the shaft. An elliptically shaped nozzle is positioned adjacent the injection side of the impeller and can control the injection rate of the slurry into the impeller, as known from the description of previous patents by the applicant. A supply of slurry mixture 72 communicates with the interior of each of the shrouds at the central portion of the impeller and can be injected into the elliptically shaped nozzles of the impeller at the sides of the impeller wheel.

[0017] Preferably, the top and bottom impellers operate at wheel speeds lower than those used in conventional abrasive particle blasting operations. Preferably, the top and / or bottom impellers rotate to generate a slurry discharge velocity of less than 200 ft / sec. More preferably, the slurry discharge velocity is set between about 100 ft / sec and 200 ft / sec. Even more preferably, the slurry discharge velocity is set between about 130 ft / sec and 150 ft / sec.

[0018] To generate sufficient slurry flow to the descaling components to remove substantially all of the scale from the sheet metal surface, it is necessary to generate an abrasive particle flow of at least 1300 pounds per minute per blast wheel. A preferred range is from about 1300 pounds per minute to about 5000 pounds per minute per blast wheel. An abrasive particle flow rate of at least 1700 pounds per minute has been found to be effective. To generate this flow rate, each descaling component includes one primary eductor feed pump 90 (FIGS. 10-12) that generates a flow rate of 1500 gallons per minute through a 10-inch diameter inlet pipe. The eductor feed pump 90 may be rated at 200 hp, 1750 rpm, and 150 psi at 1500 gpm. The eductor feed pump 90 directs the 1500 gallons per minute flow rate to a manifold 92 with two outputs. One of the two outputs leads to the inlet of the single, top-mounted impeller 50A, and the other leads to the inlet of the single, bottom-mounted impeller 50B. Manifold 92 comprises a 10-inch diameter pipe and can accommodate an eductor supply inlet consisting of a 2.5-inch diameter pipe with two narrower 3-inch diameter pipe outlets. An eductor rated for a flow of 425 gallons per minute at 125 psi for a supply liquid temperature below 130°F has been found to be effective. To prevent eductor clogging, the liquid supply is preferably clean, relatively cool (e.g., below 130°F), and free of solid particles.

[0019] After passing through the eductor 94, the feed material (usually water) mixes with abrasive particles to form a slurry that is directed to the impellers of the respective impeller wheels 50A, 50B, as previously described. After impacting the sheet metal in the descaling component, the slurry collects and is directed down the chute 72 to the rear tank 96. The rear tank 96 provides a first stage of settling and washing the discharged slurry, allowing usable abrasive particles to be collected for reuse. Optionally, scale and other particles are directed to second and third settling and washing stages, not shown. Usable abrasive particles from the rear tanks are drawn through eductor suction lines to the respective eductors. The eductors combine the abrasive particles with the liquid feed material to form a slurry that is injected into the impeller wheels of the descaling component, as required. Each of the eductor suction lines from the rear tanks comprises a 4-inch diameter pipe. Pipe connections are provided at the front of the rear tanks. Because there is only one eductor for the top-mounted impeller and one for the bottom-mounted impeller, these eductors can be located at the front of the aft tank, thereby simplifying connections compared to prior art designs with four connections at the bottom of the aft tank and providing other advantages as described. In one embodiment, the aft tank can have a trapezoidal cross-section with a trapezoidal front face. Eductor 94 for feeding top-mounted impeller 50A and eductor for feeding bottom-mounted impeller 50B are provided at the front face 98 of the aft tank 96 adjacent to a short base 100 (bottom) at the front of the trapezoidal shape of the aft tank. As described, locating the eductors at the front of the tank allows for a shorter, more direct piping path to the impeller inlets. Providing a blast wheel diameter (i.e., from blade tip to blade tip) of 17.5 inches has also been found to be effective.

[0020] Although not shown, a portion of the effluent from the rear tank 96 may be recirculated between the heavy filtration system and the rear tank. Another portion of the effluent from the rear tank 96 may be directed to a second-stage settling and washing system, including a settling tank and a filtration unit. The second settling tank may have a magnetic skimmer and separator system to remove metal oxides and other particulates from the process. The effluent from the second-stage settling tank may be directed to a second-stage filtration system. The effluent from the second-stage filtration system may then be directed to a cooling tower, where it may be cooled. The cooled and washed liquid may then be directed to the suction side of the eductor feed pump for further processing in the descaling component. The slurry delivery and recirculation system may include multiple stages of settling and washing, as needed, to produce a motive power feed liquid that is sufficiently clean as a slurry.

[0021] The type and amount of abrasive particles, along with the discharge rate of the slurry 72 mixture, are preferably controlled to enable the descaling component to produce a rust-inhibited sheet metal with a commercially acceptable surface finish (i.e., roughness). Controlling the type and amount of abrasive particles, along with the discharge rate of the slurry 72 mixture, reduces the likelihood of scale or abrasive particles becoming embedded in the soft steel surface of the sheet metal being treated. Relatively low wheel speeds for driving the slurry and angular abrasive particles have been found to be effective in removing the scale oxide layer from the strip of sheet metal being treated and in creating rust-inhibiting properties in the sheet metal being treated. By driving the slurry 72 at a speed of less than 200 feet per second, the angular abrasive particles do not significantly break down and instead gradually develop a rounded configuration through repeated impacts with the steel sheet being treated. This rounding of the abrasive particles that occurs during the descaling process results in some of the abrasive particles being reduced in size. A mix of abrasive particle sizes helps ensure more uniform surface coverage of the sheet metal being treated.

[0022] With the foregoing in mind, forming a slurry mixture from water and steel abrasive particles having a size range of SAE G80 to SAE G40 has been found to be effective. Forming a slurry mixture from water and steel abrasive particles having a size range of SAE G50 has also been found to be effective. To ensure the effectiveness of the slurry mixture, the ratio of abrasive particles to water is preferably monitored and controlled. A ratio of about 2 pounds to about 15 pounds of abrasive particles for each gallon of water has been found to be effective. A ratio of about 4 pounds to about 10 pounds of abrasive particles for each gallon of water has also been found to be effective. The ratio of abrasive particles to water is controlled in the slurry recirculation system of the descaling component 22, which may use an eductor 94, valves, and pump 90 to measure the concentration of abrasive particles and liquid.

[0023] Each descaling component 22 may be provided with one or more rinse stations. An inlet rinse station 104 may be provided inside the housing 52 adjacent the inlet opening 56, adjacent the front end 54 of the housing. The inlet rinse station 104 may include one or more bars extending from one side of the housing to the opposite side of the housing. The bars in the inlet rinse station 104 may be provided with jets positioned to direct rinse liquid onto the surface of the sheet metal 26 in a direction perpendicular to the surface of the sheet metal. Although only a top inlet rinse station is shown, a descaling component may be provided with a similarly configured bottom inlet rinse station. A blind rinse station 106 may also be provided inside the housing 52, after the slurry impingement zone of the impeller 50A at the top of the descaling component, in the direction of sheet metal movement 48. The blind rinse station 106 may include one or more bars extending from one side of the housing to the opposite side of the housing. The bars in the blind rinse station 106 may be provided with jets positioned to direct rinse liquid onto the surface of the sheet metal 26 across the entire width of the sheet metal at an acute angle to the surface of the sheet metal. Depending on the direction of the slurry being urged from the impeller 50A at the top of the descaling component to the drive side (i.e., from the operator side (e.g., first side) to the drive side (e.g., second side) or vice versa), the jets of the bars in the blind rinse station 106 may be positioned to urge the rinse liquid in the same direction so that the force from the slurry blast and the impingement from the rinse jets facilitate removing the slurry and abrasive particles from the top surface of the sheet metal within the housing. As will be explained, it is generally not necessary to provide a blind rinse station to urge rinse liquid onto the top surface of the sheet metal. An outlet rinse station 108 may be provided inside the housing 52 adjacent the rear end 58 of the housing, adjacent the outlet opening 60. The outlet rinse station 108 may include one or more bars extending from one side of the housing to the opposite side of the housing.The bars at the outlet rinse station 108 may be provided with jets positioned to direct rinse liquid onto the surface of the sheet metal 26 in a direction perpendicular to the surface of the sheet metal. Although only a top outlet rinse station is shown, the descaling component may be provided with a similarly configured bottom outlet rinse station. Operation of the rinse stations 104, 106, 108, and particularly the blind rinse station 108, may mitigate the blinding phenomenon described below.

[0024] To aid in the control of the processing line, an in-line detector is used to detect the surface condition of the top and / or bottom surfaces of the processed sheet metal after it passes through the descaling components, and the output of the in-line detector can be used to assist a processing line operator in adjusting any one or more of the following to achieve a desired surface condition: (i) pivoting, rotating, angling, and / or positioning the top impeller wheel of the first descaling component; (ii) pivoting, rotating, angling, and / or positioning the bottom impeller wheel of the first descaling component; (iii) pivoting, rotating, angling, and / or positioning the top impeller wheel of the second descaling component; (iv) pivoting, rotating, angling, and / or positioning the bottom impeller wheel of the second descaling component; or (v) increasing or decreasing the speed of the processing line. The in-line detector can be positioned after the next in a series of descaling components. For example, the detector may comprise an oxide detector positioned downstream in the processing line after the two descaling components and adapted to detect the degree of residual scale on both the top and bottom of the strip. Based in part on the detected surface condition (i.e., the detected degree of scale), the operation of the first and / or second descaling components (i.e., impeller wheel speed, impeller wheel angle, impeller wheel position) or the processing line speed (i.e., the forward speed of the sheet metal through the descaling components) may be adjusted. The detector may also be a surface finish detector, i.e., a surface profilometer, and the detected and controlled surface condition may correspond to the surface finish. The detector may also be a machine vision system, and the detected and controlled surface condition may correspond to surface flaws in the processed sheet, such as scratches, scratches, residue, metal stains, loose rust agglomerates, wear debris, etc. One or more detectors may be used to detect the surface condition on the top and bottom surfaces of the sheet metal. A combination of surface conditions may be detected.The operating parameters of each of the descaling components can be varied to achieve the desired surface condition.

[0025] In another embodiment of the descaling component, the detector may be provided with an automatic feedback mechanism, which allows for automatic control of operating parameters of the processing line based at least in part on the detected surface condition. For example, the impact velocity of the slurry may be controlled based on the detected surface condition to produce a particular surface condition, such as a surface finish of less than about 100 Ra. The impact velocity of the slurry may be varied by changing the discharge rate of the propelled slurry or by changing the speed of the processing line, i.e., the speed at which the sheet steel advances through the line. Thus, the advance rate of the sheet material through the descaling component may be varied as desired based at least in part on the detected surface condition. Additionally or alternatively, the discharge rate of the propelled slurry against the side of the sheet metal may be varied based at least in part on the detected surface condition. For systems including centrifugal impellers, the speed of the impeller wheel may be varied based at least in part on the detected surface condition. Generally, any one or more of the following may be varied based at least in part on the detected surface condition to obtain a desired surface condition: (i) pivoting, rotating, angling, and / or positioning the top impeller wheel of the first descaling component; (ii) pivoting, rotating, angling, and / or positioning the bottom impeller wheel of the first descaling component; (iii) pivoting, rotating, angling, and / or positioning the top impeller wheel of the second descaling component; (iv) pivoting, rotating, angling, and / or positioning the bottom impeller wheel of the second descaling component; or (v) increasing or decreasing the speed of the processing line. One or more detectors may be used to detect the surface condition of the top and bottom surfaces of the sheet metal. The detected surface condition of the top surface and / or the detected surface condition of the bottom surface may provide input to a control system of the automated processing line.

[0026] Applicant has determined that reducing the number of impeller wheels in each descaling component from four top-mounted and four bottom-mounted impellers to one top-mounted and one bottom-mounted impeller is a significant advantage. In particular, Applicant has unexpectedly determined that a descaling chamber arrangement with one top-mounted and one bottom-mounted impeller allows for the placement of a rinse station in the housing to more effectively rinse the strip without the rinse spray pattern interfering with the slurry blast pattern from the top-mounted impeller, effectively eliminating the blinding phenomenon identified in the prior art. Blinding occurs when abrasive particles are not properly removed from the strip. When blinding occurs, the slurry blast pattern at the downstream impeller becomes less effective because the slurry and abrasive particles remain on the sheet metal. In other words, the blast pattern of the downstream impeller is hindered by the residue of slurry and abrasive particles on the sheet metal. Blinding is less of a concern on the bottom surface of the sheet because the slurry and abrasive particles fall off the surface of the sheet metal due to gravity. However, in prior art descaling chamber designs with four impellers (two for each descaling element) intended for the top surface of the sheet metal, blinding can occur on three of the four impellers, even if the descaling chamber has a rinse station. Conventional systems use rinse stations to remove slurry and abrasive particles from the sheet, but conflicting limitations exist in conventional systems due to the size limitations of the enclosure structure and the limited area of ​​the blast pattern created by the multiple impellers and rinse stations. It is undesirable to enlarge the enclosure structure to accommodate additional rinse stations for each impeller. It is also undesirable to increase the number of rinse stations or the rinse station spray pattern within the current constraints of the enclosure.Because the increased number of rinse stations and / or rinse spray pattern interferes with the slurry blast pattern and prevents satisfactory scale removal, adding more rinse stations in conventional systems effectively limits the available space in the enclosure for the slurry to impinge on the sheet metal.

[0027] Providing one descaling component with one top-mounted impeller and a second adjacent descaling component with one top-mounted impeller on the opposite side allows for more advantageous placement of rinse stations to remove slurry and abrasive particles from the sheet and eliminate blinding. It has been determined that blinding can be eliminated when the rinse stations are placed either as a blind rinse directed at an angle from the center of the sheet metal outward toward the sides of the sheet metal (e.g., a bidirectional blind rinse), or as a blind rinse directed at an acute angle toward the sheet metal in the same direction as the impeller's blast pattern.

[0028] It has been determined that for blind rinses directed at an acute angle toward the sheet metal in the same direction as the impeller's blast pattern, this arrangement can be particularly advantageous for eliminating blinding in certain applications. In certain applications, it has been determined that a descaling component with a single top-mounted impeller oriented in one direction and coupled to a rinse station with jets oriented in the same direction (e.g., blind rinse station 108) can more effectively rinse the sheet metal after slurry impact, more effectively sweeping away slurry and abrasive particles from the sheet metal surface. Side-to-side directional rinsing cannot be accommodated in prior art descaling chamber designs with four impellers (two in each descaling component) due to the fact that the volume of slurry generated by the impellers creates an undesirable imbalance in the flow rate through the housing discharge and eductor, and would otherwise require an unnecessarily long housing to accommodate the rinse station between the impeller wheels.

[0029] Furthermore, in the current design, single impellers on the top and bottom of the housing allow the housing to be smaller in length and overall size, as opposed to prior art designs that included two impellers mounted on the top of the housing and two impellers mounted on the bottom of the housing. Housings with smaller footprints are easier to manufacture, amenable to fabrication using standard fabrication equipment, and easier to package as components in standard-sized shipping containers, reducing shipping costs. Furthermore, descaling components with smaller footprint housings can be used either as the first in a series of descaling components or as the next in a series of descaling components by simply changing the lateral position of the impellers and motors. Thus, descaling components herein can be more standard items to manufacture, compared to descaling components with two impellers mounted on the top of the housing and two impellers mounted on the bottom of the housing. Therefore, the smaller footprint of descaling components with single impellers mounted on both the top and bottom of the housing reduces space and reduces installation costs. Both designs require holes in the facility to accommodate discharge chutes, tanks, pumps, piping, valves, and eductors. While conventional designs require holes 20 feet deep, the exemplary descaling chamber with its reduced footprint and size requires a hole approximately 6.5 feet deep. Additionally, compared to conventional systems with two impellers mounted on the top of the enclosure and two impellers mounted on the bottom of the enclosure, the exemplary descaling chamber uses less energy per ton of processed sheet metal.

[0030] The smaller enclosure footprint also allows for the elimination of mechanical components that enable threading of sheet metal through the enclosure's inlet and outlet openings. Prior art descaling components with two top-mounted impellers and two bottom-mounted impellers are quite long. Therefore, to thread the coil head through the first and second descaling components, each descaling component is provided with a series of threading arms and fingers that extend downward in the enclosure to help support the coil head as it moves through the descaling component. When the coil head is clamped by a recoiler at the end of the processing line, the threading arms and fingers can return to their upper positions within the enclosure. However, during the threading operation, the components are deployed to their lower positions and are subjected to blasting from the impellers. As a result, the components experience significant wear. Descaling components with a single top- and bottom-mounted impeller are shorter in extension. Thus, during threading, the head of the coil can be supported on rollers located between the first and next in the series of descaling components. In this way, threading arms and fingers are not needed because the head of the coil can be more easily threaded through the first and next in the series of descaling components. Eliminating the threading arms and fingers reduces overall maintenance costs associated with the processing line because threading arms and fingers are high-maintenance components.

[0031] Applicant has also determined that a descaling component with a single motor-driven impeller at the top allows for more efficient flow of abrasive particles and slurry from the eductor located in the rear tank to the single motor-driven impeller at the top. The smaller footprint of the descaling component's housing allows for a shorter, more direct path of piping to supply slurry to the single motor-driven impeller at the top. As a result, the motor for the top impeller uses less energy compared to the motors of prior art designs with two top-mounted impellers. Furthermore, because of the smaller footprint of the housing, the rear tank can be positioned to allow the eductor to be mounted at the front rather than the bottom of the rear tank. This allows for a shorter, more direct path of piping to supply slurry to the single motor-driven impeller at the top.

[0032] While the apparatus and method of the present invention have been described herein with reference to several embodiments thereof, it should be understood that variations and modifications can be made to the basic concepts of the invention without departing from the intended scope of the following claims.

Claims

1. 1. A method for descaling sheet metal, comprising: providing a first component for a descaling chamber for blasting slurry, the first component comprising a housing with an interior having a top and a bottom, a first side and a second side, and a front side and a rear side, the front side having an inlet opening to the interior and the rear side having an outlet opening to the interior, the front side and the rear side being transverse to the sides, the housing having a single motor-driven slurry propelling impeller mounted to the top of the housing, the single motor-driven slurry propelling impeller at the top propelling the first component as sheet metal passes through the interior of the housing of the first component; providing a first component adapted and configured to urge slurry within the housing on a top surface of a sheet metal across a width of the sheet metal in a first direction extending from a side toward the second side, the housing having a single motor-driven slurry-propelling impeller attached to the bottom of the housing, the single motor-driven slurry-propelling impeller at the bottom adapted and configured to urge slurry into the housing on a bottom surface of the sheet metal across a width of the sheet metal in the first direction as the sheet metal passes through the housing interior of the first component; providing a second component for a descaling chamber for blasting slurry, the second component comprising a housing with an interior having a top and a bottom, a first side and a second side, and a front side and a rear side, the front side having an inlet opening to the interior and the rear side having an outlet opening to the interior, the front side and the rear side being transverse to the sides, the housing having a single motor-driven slurry propelling impeller mounted to the top of the housing, the single motor-driven slurry propelling impeller at the top being adapted to propel sheet metal through the interior of the housing of the second component; providing a second component adapted and configured to urge slurry within the housing onto a top surface of the sheet metal across a width of the sheet metal in a second direction extending from the second side toward the first side, the housing of the second component having a single motor-driven slurry-propelling impeller at the bottom of the housing, the single motor-driven slurry-propelling impeller at the bottom adapted and configured to urge slurry onto a bottom surface of the sheet metal across a width of the sheet metal in the second direction as the sheet metal passes through the interior of the housing of the second component; positioning the first component adjacent to the second component to form a slurry blasting descaling chamber, the positioning comprising positioning the first component relative to the second component such that the first side of each of the first components is aligned with one side of the slurry blasting descaling chamber and the second side of each of the first components is aligned with the opposite side of the slurry blasting descaling chamber, and such that sheet metal to be processed in the descaling chamber passes through the inlet opening on the front side of the first component, passes through the interior of the first component, passes through a rinsing station of the first component, passes through the outlet opening on the rear side of the first component, passes through the inlet opening on the front side of the second component, passes through the interior of the second component, and passes through the outlet opening on the rear side of the second component; A method comprising:

2. providing a rinse station in an enclosure of the first component, the rinse station adapted to urge rinse liquid onto a top surface of the sheet metal across an entire width of the sheet metal in the first direction as the sheet metal passes through an interior of the enclosure of the first component; providing a rinse station in the housing of the second component, the rinse station adapted and configured to urge rinse liquid onto a top surface of the sheet metal across an entire width of the sheet metal in the second direction as the sheet metal passes through the interior of the housing of the second component; The method of claim 1 further comprising:

3. providing a rear tank for the first component, the rear tank having a front portion and a rear portion, the front portion of the rear tank corresponding to the front portion of the first component; connecting a slurry supply eductor to the single motor-driven slurry propelling impeller mounted on top of the first component at a pipe connection at the front of the aft tank; The method of claim 1 further comprising:

4. 4. The method of claim 3, further comprising the step of connecting another eductor supplying slurry to the single motor-driven slurry propelling impeller mounted to the bottom of the first component at another pipe connection in the front of the rear tank.

5. 5. The method of claim 4, wherein the step of providing the front portion of the aft tank to the first component includes providing the aft tank with a trapezoidal shaped surface with a pipe connection for the eductor adjacent a short base of the trapezoidal shaped surface.

6. providing a rear tank on the second component, the rear tank having a front portion and a rear portion, the front portion of the rear tank corresponding to the front portion of the second component; connecting a slurry supply eductor to the single motor-driven slurry propelling impeller mounted on the top of the second component at the forward pipe connection of the rear tank; The method of claim 1 further comprising:

7. 7. The method of claim 6, further comprising the step of connecting another eductor supplying slurry to the single motor-driven slurry propelling impeller mounted to the bottom of the second component at another pipe connection in the front of the rear tank.

8. 8. The method of claim 7, wherein the step of providing the front portion of the aft tank to the second component includes providing the aft tank with a trapezoidal shaped surface with a pipe connection for the eductor adjacent a short base of the trapezoidal shaped surface.

9. 2. The method of claim 1, further comprising advancing the sheet metal through the descaling chamber by advancing the sheet metal through the entrance opening in the front side of the first component, through an interior of the first component, through the exit opening in the rear side of the first component, through the entrance opening in the front side of the second component, through an interior of the second component, and through the exit opening in the rear side of the second component.

10. urging slurry across the entire width of the sheet metal using the single motor-driven slurry propelling impeller at the top of the first and second components to remove substantially all of the scale on the top surface of the sheet metal; urging slurry across the entire width of the sheet metal using the single motor-driven slurry propelling impeller at the bottom of the first and second components to remove substantially all of the scale on the bottom surface of the sheet metal; 10. The method of claim 9, further comprising:

11. 1. A method for descaling sheet metal, comprising: providing a first component for a descaling chamber for blasting slurry, the first component comprising a housing with an interior having a top and a bottom, a first side and a second side, and a front side and a rear side, the front side having an inlet opening to the interior and the rear side having an outlet opening to the interior, the front side and the rear side being transverse to the sides, the housing having a single motor-driven slurry propulsion impeller mounted to the top of the housing and a single slurry propulsion impeller wheel at the bottom of the housing; providing a second component for a descaling chamber for blasting slurry, the second component comprising a housing with an interior having a top and a bottom, a first side and a second side, and a front side and a rear side, the front side having an inlet opening to the interior and the rear side having an outlet opening to the interior, the front side and the rear side being transverse to the sides, the housing having a single motor-driven slurry propelling impeller mounted to the top of the housing and a single motor-driven slurry propelling impeller at the bottom of the housing; positioning the single motor-driven slurry propelling impeller at the top and the single motor-driven slurry propelling impeller at the bottom in the first component so that each urges slurry into the interior of the enclosure on a top surface and a bottom surface of the sheet metal, respectively, across an entire width of the sheet metal in a first direction from the first side toward the second side as the sheet metal passes through the interior of the first component; positioning the single motor-driven slurry propelling impeller at the top and the single motor-driven slurry propelling impeller at the bottom in the second component so that each propels slurry within the housing on a top surface and a bottom surface of the sheet metal, respectively, across an entire width of the sheet metal in a second direction from the second side toward the first side as the sheet metal passes through the interior of the second component; positioning the first component adjacent to the second component to form a slurry blasting descaling chamber, the positioning comprising positioning the first component relative to the second component such that the first side of each of the first components is aligned with one side of the slurry blasting descaling chamber and the second side of each of the first components is aligned with the opposite side of the slurry blasting descaling chamber, and such that sheet metal to be processed in the descaling chamber passes through the inlet opening on the front side of the first component, passes through the interior of the first component, passes through the outlet opening on the rear side of the first component, passes through the inlet opening on the front side of the second component, passes through the interior of the second component, and passes through the outlet opening on the rear side of the second component; A method comprising:

12. providing a rear tank for the first component, the rear tank having a front portion and a rear portion, the front portion of the rear tank corresponding to the front portion of the first component; connecting an eductor supplying slurry to the single motor-driven slurry propelling impeller mounted on the top of the first component at a pipe connection in the front of the aft tank; The method of claim 11 further comprising:

13. 13. The method of claim 12, further comprising connecting another eductor supplying slurry to the single motor-driven slurry propelling impeller mounted to the bottom of the first component at another pipe connection in the front of the rear tank.

14. 14. The method of claim 13, wherein the step of providing the front portion of the aft tank to the first component includes providing the aft tank with a trapezoidal shaped surface with a pipe connection for the eductor adjacent a short base of the trapezoidal shaped surface.

15. providing a rear tank on the second component, the rear tank having a front portion and a rear portion, the front portion of the rear tank corresponding to the front portion of the second component; connecting a slurry supply eductor to the single motor-driven slurry propelling impeller mounted on the top of the second component at the forward pipe connection of the rear tank; The method of claim 11 further comprising:

16. 16. The method of claim 15, further comprising connecting another eductor supplying slurry to the single motor-driven impeller mounted to the bottom of the second component at another pipe connection in the front of the rear tank.

17. 17. The method of claim 16, wherein the step of providing the aft tank for the second component includes providing the aft tank with a trapezoidal shaped surface with a pipe connection for the eductor adjacent a short base of the trapezoidal shaped surface.

18. 12. The method of claim 11, further comprising advancing the sheet metal through the descaling chamber by advancing the sheet metal through the entrance opening in the first component, through an interior of the first component, through the exit opening in the rear side of the first component, through the entrance opening in the front side of the second component, through an interior of the second component, and through the exit opening in the rear side of the second component.

19. urging slurry across the entire width of the sheet metal using the single motor-driven slurry propelling impeller at the top of the first and second components to remove substantially all of the scale on the top surface of the sheet metal; urging slurry across the entire width of the sheet metal using the single motor-driven slurry propelling impeller at the bottom of the first and second components to remove substantially all of the scale on the bottom surface of the sheet metal; 20. The method of claim 18, further comprising:

20. providing a rinse station in an enclosure of the first component, the rinse station adapted to urge rinse liquid onto a top surface of the sheet metal across an entire width of the sheet metal in the first direction as the sheet metal passes through an interior of the enclosure of the first component; providing a rinse station in the housing of the second component, the rinse station adapted and configured to urge rinse liquid onto a top surface of the sheet metal across an entire width of the sheet metal in the second direction as the sheet metal passes through the interior of the housing of the second component; The method of claim 11 further comprising:

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