US3673980A

US3673980A - Protective and supporting means for apparatus for continuously coating steel strip

Info

Publication number: US3673980A
Application number: US85487A
Authority: US
Inventors: Theodore H Krengel; Richard L Pool
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-10-30
Filing date: 1970-10-30
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04

Abstract

In order to operate a continuous steel forming and coating line at high speeds, supports for the moving steel are provided at various points such as at a location where it has its surface prepared to receive the coating and at the coating station. In addition, means are provided to shut down the line in the event there is a jam or binding causing the steel to buckle or bend creating a hazard.

Description

O Umted States Patent [151 3,673,980 Krengel et al. 1 July 4, 1972 [54] PROTECTIVE AND SUPPORTING [56] References Cited MEANS FOR APPARATUS FOR- UNITED STATES PATENTS CONTINUOUSLY COATING STEEL STRIP 2,890,134 6/1969 Linden et a1..... ..1 17/51 3,122,114 5/1965 Krengel et a1 ..29/200 [72] Inventors: Theodore ll. Krengel, 637 Park Drive, 3,559,280 2/1971 Mailhiot et al. ..29/200 B Flossmoor, 111. 60422; Richard L. Pool, 3101 W. 173111 SL, Hazelcrest, "I. 60429 Primary Examiner-Henry S, Jaudon Oct. 3 Attorney-McDougall, Hersh & Scott [21] App1.No.: 85,487 [57] ABSTRACT In order to operate a continuous steel forming and coating line at high speeds, supports for the moving steel are provided at various points such as at a location where it has its surface U.S. e ared to receive the oating and at the coating station, In [51] -l t Cl 805 3633 addition, means are provided to shut down the line in the n c 1 58 Field of Search ..29/200 R, 200 B, 460, 430; event there a Jam or b'ndmg causmg the Steel to buck e or bend creating a hazard.

PATENTEnJuU-4 I972 SHEET 10F 3 INVENTORS W P'ATENTEDJULA IQR I 3,873.980

.' I snmanra PATENTEDJUL 41272 3.673.980

sum 30F 3 FIG: 4' /2( 1/40 122 118 jf w 15 II/ II III III/I IIIIIIIIII III IIII I 111/ 1 1/1/1111 PROTECTIVE AND SUPPORTING MEANS FOR APPARATUS FOR CONTINUOUSLY COATING STEEL STRIP BACKGROUND OF THE INVENTION This invention relates generally to metal working apparatus. It relates more specifically to apparatus useful in the high speed production of steel.

The patent to Krengel et al., US. Pat. No. 3,122,l 14, shows a continuous tube forming and galvanizing system wherein strip material supplied from a reel is formed into tubing, the seam welded, and after surface preparation passed through a zinc bath to galvanize it. In order to derive all possible economic benefits from such a system, it is desired to operate it at the highest possible rates. However, as the operating speeds of such systems are increased, it is possible on occasion for'the formed tubing to bind at a particular station causing the tubing to buckle or bend. Such buckling or bending, if great enough, can result in a jam or pile of bent tubing at a particular point. Apart from waste and losses due to the necessity to shut down the line and clear up the situation there are obvious hazards to operators and possibilities of damage to the equipment.

In addition to the possibilities of jams, there is also a problem created by the movement of the formed tubing away from the center line of its travel through the line. That is, as the tubing moves at the high speeds desired there is a tendency to vibrate. Under certain circumstances, these movements can build up causing binding at a particular location or it will move toward an element such as an electrostatic paint sprayer creating a potential fire hazard.

Therefore, it is an object of this invention to provide a novel means for limiting the movement of steel strip in a line which continuously coats such strip material and which may also form the same into desired configurations.

It is another object of this invention to provide a novel means for protection against jams and hazards in a line which continuously coats strip material and which may also form the same into desired configurations.

It is still another object of this invention to provide a means for shutting down a line which continuously coats strip material and which may also form the same into desired configurations in the event a potentially hazardous situation occurs.

SUMMARY OF THE INVENTION The above and other objects are achieved in one embodiment of the invention by providing means at various locations for restraining movement of steel material in a line which continuously coats such material and forms the same into desired shapes, if desired. In order to provide for further protection against excessive stoppage and hazards, means responsive to excessive excursions of the moving material are provided to stop the line.

BRIEF DESCRIPTION OF THE DRAWINGS The invention itself is set forth in the claims appended hereto and forming a part of this application. An understanding of a particular embodiment thereof may be had by reference to the detailed description taken in conjunction with the drawings in which:

FIG. 1 is a block diagram illustration of a continuous tube forming and galvanizing line which may be constructed in accordance with the invention;

FIG. 2 is a side view, partially in section, of an acid cleaning tank forming a part of the Surface Preparation stage of the line of FIG. 1;

FIG. 3 is a plan view, partially in section, of the acid cleaning tank of FIG. 2;

FIG. 4 is a view along the lines 4-4 of FIG. 2;

FIG. 5 is a view along the lines 5-5 of FIG. 2;

FIG. 6 is a view along the lines 6-6 of FIG. 2;

FIG. 7 is a sectional elevational view of apparatus in the galvanizing stage of a continuous line in accordance with the invention;

FIG. 8 is a side view of the upper kettle forming a part of the galvanizing stage of the line of FIG. 1;

FIG. 9 is a plan view of the upper kettle of FIG. 8;

FIG. 10 is a view along the lines 10-10 of FIG. 8;

FIG. 11 is a view along the lines 11-11 ofFlG. 10;

FIG. 12 is a view along the lines 12-12 of FIG. 10;

FIG. 13 is a view along the lines 13-13 of FIG. 8;

FIG. 14 is a partial side view of a cooling tank forming a part of the cooling stage of the line of FIG. 1;

FIG. 15 is a view along the lines 15-15 of FIG. 14;

FIG. 16 is a side view of a guide roll support mounted in the cooling tank of FIG. 14; and

FIG. 17 is an illustration of a paint booth forming a part of the painting stage of the line of FIG. 1.

DETAILED DESCRIPTION An embodiment of this invention is shown in FIG. 1 which illustrates in block diagram fonn a continuous line for galvanizing and forming strip steel. A more detailed showing and description of a continuous line which may include the apparatus of the invention is shown in the patent to Krengel et al., US. Pat. No. 3,122,114. It should be understood that this showing and the reference to the Krengel et al patent is by way of exemplification only. For instance, the Krengel et al patent discloses a continuous line where strip steel is fed from a roll of such material and formed and welded so as to produce tubing which is then galvanized in a zinc bath. However, it is contemplated that the apparatus of this invention may be used in a continuous galvanizing line wherein the strip steel is not necessarily formed into tubing or conduit but rather may be formed into other shapes or not formed at all. Further, that whereas reference is made to galvanizing it should be understood that the protective coating applied to the strip material formed or unformed may be constituted by materials other than zinc. For instance, a composition containing zinc and aluminum could be used equally well so that the phrase galvanizing material" is intended to cover zinc alone or zinc in combination with other metallic materials, such as aluminum.

Referring now to FIG. 1 of the drawing, apparatus in accordance with the invention includes a payout reel 2 on which is mounted a coil of strip steel. The payout reel is capable of free rotational movement to pay out the strip as required by the continuous line. In a line of this type, the strip steel is processed substantially continuously at a relatively constant rate therethrough. Advancement is efiected primarily by engagement between the strip steel and the forming and sizing rolls rotated at a relatively constant speed whereby the strip steel is drawn into the line for processing.

Since the lengths of the steel strip in the coils come to an end after a short period of operation of the line and since strip is taken up continuously by the line in its continuous operation, it is essential to provide means for splicing the end of one coil with the leading end of another coil for joinder of the strips into continuous lengths without stoppage of the mill in its continuous operation. This is accomplished by providing a joining stage 4 which is constituted by a welder and appropriate clamping means. As described in U.S. Pat. No. 3,122,1l4, looping means may also be provided so as to permit the continuous operation of the line. After joining, the strip may enter a forming stage 6 constituted by a series of conventional forming rolls whereby the strip is deformed from a flat section to a rounded tube with the edges of the strip in abutting relation to form the seam of the tube. As pointed out above, the forming rolls need not be tube forming rolls but may form the strip into other desired shapes.

From the forming stage the formed strip is advanced directly to a welding stage 8 if tubing or some other closed shape is to be formed. At this stage the abutting free edges of the strip formed to a tubular shape are joined by welding, preferably using a continuous resistance welder in order to keep the upset on the inside of the formed tubing at a After the tubing has been welded to provide a continuous weld throughout the length thereof, the tubing is advanced from the welders to elements linearly aligned therewith for washing and pickling the outer surface of the formed tubing in preparation for continuous galvanizing. The elements for effecting this operation are designated in FIG. 1 as the surface preparation stage 10. As set out in US. Pat. No. 3,122,114, the surface preparation stage includes a number of elements such as alkali wash for removing grease and the like from the surface of the steel strip or tubing, means for rinsing the wash and means for pickling the surface of the strip. This latter means in accordance with the invention takes the form of an acid bath held in a tank 12, shown in FIG. 2, through which the moving steel passes. After pickling, the steel is once again rinsed in the surface preparation stage and then passes to a preheating stage 14. In the preheating stage, the tubing is heated to an elevated temperature, preferably a temperature above the melting point of the galvanizing material so that the galvanizing reactions will be carried out more rapidly and with greater uniformity.

After preheating, the steel passes to a galvanizing stage 16 which includes a housing 18 as shown in FIG. 7. In the galvanizing stage, the outer surface of the steel, if it is in the form of tubing or some other closed shape, is coated with the galvanizing material; otherwise the top, bottom and side surfaces of a strip are coated. After galvanizing, the steel enters a cooling tank 21 as shown in FIG. 14. After cooling, the steel may then pass through sizing rolls which have for their purpose the reduction of the now galvanized material to a final desired size. Whereas the sizing stage 22 is shown in the embodiment of FIG. 1 as being located after the cooling stage 20, if desired, this stage may be elsewhere in the line. For instance, this stage could be located after the welding stage 8 if it were desired to size the end product prior to galvanizing.

In some cases, it may be desired to coat or paint the galvanized surface with a pigmented material either to color it or provide additional protection and a painting stage 24 may be provided for that purpose. Included in the painting stage 24 is a booth 26 opened on one side whereby coating materials may be sprayed on the now galvanized steel as it passes through the line.

After painting in the stage 24, if such a stage is included in the line, a shear 28 is provided to cut the finished product to desired lengths.

The acid bath used in the surface preparation stage is held in the tank 12 illustrated in FIGS. 2 through 6. The tank is formed so that the tank material in contact with the acid is an acid resistant material such as polypropylene. As shown in FIGS. 2 and 3, the tank 12 is an elongated tank having a bottom 30,

end walls

32 and 34, and

side walls

36 and 38. Spaced from the

end walls

32 and 34 are

barriers

40 and 42, respectively, which with their associated end walls form compartments 44 and 46, respectively. Each end wall and barrier is formed with an opening spaced upwardly from the bottom 30 aligned with each other and positioned in line with the path of the moving steel so as to provide entry and exit openings. Spaced along the length of the tank are a plurality of supports 48, each of which is provided with an opening 50in line with the openings of the end walls and barriers. Each support 48 is provided with an aperture 52 at its bottom so that the acid bath may pass freely between the supports and exit therefrom.

Fresh acid is supplied to the tank through a conduit 54 opening into the side of the tank and the old acid in the bath is drained through an opening 56 in the bottom 30.

The acid tank is provided with a pair of longitudinally arranged spaced apart spray pipes 55 connected to the conduit 54 and supported by the supports 48 to overlie the formed tubing. The pipes are provided with a plurality of spray nozzles 57 positioned to direct the spray 59 on the tubing. Thus, the spray is directed forcefully from the spray nozzles onto the tubing to react with the oxides on its surface particularly those that are formed at the weld.

An upwardly opening channel member 60 is provided around the periphery of the tank to receive the downwardly depending flanges 62 of a cover 64 provided to prevent acid from splashing out of the tank during the operation of the line. Handles 66 may be provided to remove the cover when desired.

Steel strip formed or unformed entering the acid bath holding tank 12 at the end 32 passes through the opening in that end and that in the barrier 40 and each of the openings 50 exiting through the openings in the banier 42 and end 34. Inasmuch as each of the openings in the supports and ends of this tank completely encompass the path of strip, their peripheries function to limit any excessive movement of the steel material away from its desired path so as to maintain its travel in substantially a straight line. In this manner, any tendency of the steel to oscillate along its path of travel is substantially eliminated. Consequently, the line can be operated at relatively high speeds and the steel will not move out of its path of travel to possibly buckle and require that the line be shut down.

Another location in the line where it is desirable to provide guide or restraining means is in the galvanizing stage 16. FIGS. 7 through 13 illustrate the housing 18 and the guide elements provided therein to limit the movement of the traveling steel material. FIG. 7 illustrates the housing 18 constructed so as to provide an enclosure holding a molten reservoir of galvanizing material in an enclosed atmosphere which is preferably constituted by a reducing or non-oxidizing gas such as nitrogen. While the housing 18 is disclosed as a sealed enclosure it is desirable to provide a means whereby access may be had to its interior in order to replenish the supply of galvanizing material but at the same time maintain the inert gas atmosphere.

Thus, the housing comprises a rectangular hood 68 having a horizontally disposed top wall 70 and side and end walls 72 which depend downwardly from the edges of the tube wall into a trough 74 facing upwardly from a frame 76 which extends all about the galvanizing zone. The bottom edges 78 of the side walls are received within the trough for support of the hood on the bottom wall thereof. The trough is at least partially filled with a granular material 80 such as fine sand into which the lower edge of the side walls become embedded to effect a sealing relationship all around which militates against the flow of free gases for atmospheric control. One or more inlets 82 for the inert or reducing gas are provided in the walls of the hood for introduction of such gases in amounts to maintain the desired atmosphere therein.

The galvanizing means comprises an elongated horizontally disposed trough or upper kettle 82 aligned axially with the line of travel of the steel material for passage of the material axially through an intermediate section of the kettle forming an inlet 84 at one end to the outlet 86 at the opposite end. Included are one or more passages 88 connected to a reservoir 90 of molten galvanizing material with means for displacement of the molten material from the reservoir to the inlets at a rate sufficient to maintain the kettle substantially filled with molten galvanizing material so as to cover the steel advancing therethrough.

As seen in FIGS. 8 and 9, the upper kettle includes a first side wall 91 and a second side wall 92 and that the side wall 91 is higher than the side wall 92. Mounted on the side wall 91 are a plurality of brackets 94 which are substantially T-shape in cross section. Each bracket is provided with vertically extending slots 96 through which suitable fastening means such as bolts 98 may be passed to engage in appropriate threaded holes in the side wall 91 so that the brackets may be adjusted in a vertical direction. The leg of each T-shaped bracket is provided with an opening in which is mounted a guide 100, the inner periphery of which is shaped to conform substantially to the surface of the steel material being galvanized. As may be seen, the openings formed by the inner peripheries 102 of the guides 100 are aligned with each other and with the path of travel of the moving steel material so that they function to maintain the path of travel in substantially a straight line. The

material selected for the guides 100 should be one which will resist alloying with the galvanizing material so as to prevent a build up of such material on the guide whereby it will maintain its desired size and configuration. The guides thus provide a means to restrain any tendency of rapidly moving material to oscillate about its path of travel and therefore are part of the means to permit operation of the line at relatively high speeds.

In order to provide for a continuous flow of molten galvanizing material in the upper kettle 82 and at the same time maintain the level of material in that kettle high enough to completely cover thesteel material moving therethrough, one end of the side wall 92 is cut away so as to provide a lower level portion 104. A trough 106 extends from the portion 104 so that molten material entering the upper kettle through the passage 88 drains through the portion 104 down the trough 106 back to the reservoir 90.

The tank 21 forming a part of the cooling stage 20 is illustrated in FIGS. 14 through 16. The tank is maintained with a continuously circulating bath of cooling water so that the hot galvanized material is cooled as it passes therethrough causing the galvanizing material to solidify on the surface of the steel. Mounted in the cooling tank 21 are a pair of guide roller supports 108. Each guide roller support is constituted by a pair of

angular brackets

110 and 112 secured to the base of the tank 22. Mounted on vertically extending

portions

114 and 116, respectively, of the

brackets

110 and 112 are a pair of

slide members

118 and 120 connected by a cross piece 122 so as to form a U-shape configuration. Each slide member is provided with elongated vertically extending slots 124 through which pass threaded fastening means 126 engaging in the

bracket portions

114 and 116 so that the vertical height of the slide members can be adjusted. Mounted on suitable bearing means on a shaft 128 extending between the

bracket portions

114 and 116 and mounted on the shaft is a guide roller 130 on which the moving steel material is supported.

Secured by means of threaded fasteners 132 extending through vertical slots 134 is a third slide element 136. Mounted on top of the third slide element 136 is a limit switch 138 having an actuator 140 extending over the path of travel of the strip material. By adjusting the vertical height of the slide element 136 a limit can be fixed for any vertical movement of the strip material, this limit being determined by the height of the switch actuator 140. If the moving strip material should be caused for one reason or another, such as a jam or binding some place in the line, to move upwardly out of its path of travel, it will contact the switch actuator 140 causing the switchl30 to be operated. The switch 130 is connected by leads 141 into the electrical power and control circuit of the line in a manner not shown so as to be effective to interrupt the electric power to the various drive motors in the line so as to shut them down in the event of excess movement of the steel material.

When the line is provided with a coating stage as indicated at 24 in FIG. 1, a spray booth such as shown at 26 in FIG. 17 may be provided. The booth is closed on all sides except one, 142, so that desired coating such as paint may be sprayed upon the now galvanized steel material. One side of the booth 26 is provided with an entry opening 144 while its other side is provided with an exit opening 146. Mounted on the wall of the booth around the exit opening 146 is a support 148 on which is mounted four limit switches 150, each having an actuator 152. The actuators are positioned a predetermined distance away from the path of travel of the steel material so as to lie in planes over and under and to either side of the path of travel. In the event that the material should depart more than a predetermined distance from its desired path of travel, one or more of the actuators will be contacted to operate its associated limit switch. The associated limit switches, as before, may be connected into the electrical system for the line in order to shut it down in this eventuality.

In addition, since the spraying apparatus may be constituted by an electrostatic spray system, the switches may be connected to the power supply for that system to interrupt it in the event of excess movement of the steel material. This is particularly important since the electrical potential in the vicinity of such spraying apparatus is very high and very frequently the coatings or paint used are inflammable so that if the steel material were to move to the vicinity of the spraying apparatus inasmuch as it is an electrical conductor a spark may be created igniting the coating material.

Each of the guide or restraining elements and the protective limit switches provided at the locations indicated cooperate to permit the line to operate at relatively high speeds by restraining the rapidly moving steel material in a desired path and act to stop the operation of the line in the event that the steel material moves from the desired path an excessive amount in certain strategic locations.

Obviously, various elements of the invention may be modified and it is intended to cover by the claims appended hereto all such modifications as fall within their scope.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. Apparatus for the continuous galvanizing of steel supplied to the apparatus in the form of rolled strip comprising means for preparing the surface of the steel for galvanizing including an elongated tank for holding an acid bath, said tank formed from an acid resistant material, a plurality of spaced supports mounted in said tank along the length thereof, each support having an opening in line with the other supporting openings and in line with the moving steel, a galvanizing stage including a kettle for holding molten galvanizing material, said kettle having a bottom and side and end walls upstanding therefrom, an opening in each end wall in line with each other and the moving steel whereby the steel may enter at one end of the kettle and exit from the other, a plurality of guides mounted for vertical adjustment on one side wall of said kettle for holding the moving steel in a relatively fixed path as it passes through said kettle, a cooling stage including a cooling tank following said galvanizing stage, and at least one guide roller support having a vertically adjustable roller thereon mounted in said cooling tank.

2. The apparatus of claim 1 wherein each spaced support in said elongated acid bath holding tank is provided with an aperture at its bottom.

3. The apparatus of claim 2 wherein said elongated acid bath holding tank is provided with barriers spaced from each end wall thereof forming compartments and said barriers are provided with openings in line with said support openings to permit passage of the moving steel.

4. The apparatus of claim 3 wherein said barriers are provided with apertures at the bottom to permit liquid flowing through said barrier openings into said compartments to flow back into said tank.

5. The apparatus of claim 4 wherein said elongated acid bath holding tank is provided with an upwardly facing channel extending around its periphery and a cover including downwardly depending flangers engageable in said channel.

6. The apparatus of claim 1 wherein said kettle is mounted in a housing for holding a bath of molten galvanizing material and is spaced above the level of the bath, and said guides are mounted in brackets each having a base and a flange extending nonnally to said base.

7. The apparatus of claim 6 wherein the base of each bracket is provided with slots, attaching means passing through said slots and one side wall of said kettle to vertically and adjustably mount each bracket and guide on said one side wall.

8. The apparatus of claim 7 wherein said one side wall is higher than the other side wall of said kettle and the base of each bracket extends on said one side wall above said other side wall.

9. The apparatus of claim 7 wherein a portion of one of the side walls of said kettle is lower than the rest of that side wall and a trough extends downwardly from said lower portion toward the bottom of said housing to permit galvanizing material held in said kettle to return to a bath of molten galvanizing material held in said housing.

10. The apparatus of claim 1 wherein a vertically adjustable limit switch is mounted above said guide roller and has an actuating element extending over said guide roller above the path of the moving steel whereby said switch may be actuated in the event the moving steel moves out of its desired path in excess of a predetermined amount.

1 1. The apparatus of claim 10 wherein said guide roller support comprises a pair of angular supports and said guide roller is mounted between said supports.

12. The apparatus of claim 1 1 including a pair of slide members having slots therein each engaging one of said angular supports, securing means passing through said slots to permit said slide members to be vertically adjustably secured to said angular supports, and bearing means mounting said guide roller on said slide members.

13. The apparatus of claim 12 including a third slide member having slots therein adjustably mounted on one of said angular supports and said limit switch is mounted on said third slide member.

14. The apparatus of claim 1 including a stage for coating the galvanized steel with a pigmented protective coat including a spray booth having entry and exit openings in line with the path of the moving steel and limit switch means having actuating means extending around the path of the moving steel around one of said openings to be actuated if the moving steel moves out of a predetermined path.

15. The apparatus of claim 14 wherein said limit switch means includes four limit switches each having a separate actuator and the actuators are disposed over, under and on either side of the path of moving steel.

Claims

6. The apparatus of claim 1 wherein said kettle is mounted in a housing for holding a bath of molten galvanizing material and is spaced above the level of the bath, and said guides are mounted in brackets each having a base and a flange extending normally to said base.

11. The apparatus of claim 10 wherein said guide roller support comprises a pair of angular supports and said guide roller is mounted between said supports.

12. The apparatus of claim 11 including a pair of slide members having slots therein each engaging one of said angular supports, securing means passing through said slots to permit said slide members to be vertically adjustably secured to said angular supports, and bearing means mounting said guide roller on said slide members.