US2037421A - Treatment of strip material - Google Patents

Description

April 14, 1936. c. w. LITTLER TREATMENT OF STRIP MATERIAL 2 Sheets-Sheet 1 J3 lxii i fi i 55 1 INVENTOR April 14, 1936.

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Patented- Apr. 14, 1936 UNITED STATES TREATBENT 0F STRIP MATERIAL Carl W. Littler, Pittsburgh, Pa., assignor to Jones & Laughlin Steel Corporation, Pittsburgh, Pa., a corporation of Pennsylvania AppiicationJuly '1, 1933, Serial No. 679,365 r: Claims. (01. 148-8) This invention relates broadly to the treatment of strip material, and more particularly to certain methods and apparatus for the continuous treatment of material in long lengths. The invention relates still more particularly to the treatment of strip metal which may be supplied either in coils or otherwise.

Although, as above indicated, the invention in its broader aspects is not limited to the treatment of strip metal, the invention is especially well adapted for performing certain treating operations, preferably continuously, on metal strip. Examples are pickling and coating such as tinning and galvanizing. As a specific example for purposes of illustration and explanation I shall describe certain methods of and apparatus for continuously pickling strip metal supplied in coils.

One of the purposes of pickling metal is to clean its surface, removing oxide, scale and dirt. The pickling solution is of acid characteristics and by chemical action separates the scale, etc., from the surface of the metal. Pickling of relatively short wieldable shapes such as sheets is ordinarily accomplished by dipping, during which the sheets may be held on edge to allow the pickling solution and separated particles to drain off, leaving the metal clean and rendering it unnecessary to remove particles therefrom by an additional step.

A'different problem is presented in the pickling of strip metal, that is to say, metal of such length that it cannot simply be'dipped as a unit so as to have its entire surface pickled. The usual prac-- tice in pickling strip metal has been to pass the same continuously longitudinally through a long pickling vat or vats, allowing the metal to remain in contact with the pickling solution for a sufficient time to accomplish loosening of the undesirable particles therefrom. Continuous picklers for strip metal have been very long, sometimes as much as 200 feet or more, thus consuming valuable floor space. Furthemiore, the strip metal has been fed to such picklers horizontally, that is, with the metal lying in a generally horizontalplane as it advances.

at an angle to the horizontal or even in, a generally vertical direction for adistance, as when entering or leaving a pickling vat, but the strip ordinarily lies horizontally or substantially so during treatment.

It has been found that the continuous pickling of strip metal in a long pickling vat or. series of vats with the metal lying substantially horizontally is undesirable, not only by reason of the great amount of floor space taken up by the vat, but also because the particles of scale, et'c., loosened from the upper surface of the metal by the pickling solution tend to a certain extent to remain in place or lie on such upper surface, and when the strip is drawn out of the pickler and Often the metal is guided coiled up undesirable particles will adhere to the strip and enter the coil.

I treat strip material by disposing the same substantially on edge and bringing it into contact with a treating fluid so that the strip material is treated by the treating fluid while substantially on edge, and moving relatively to each other the treating fluid and strip material. For example, in pickling strip metal I may pass the strip through a pickling bath in such manner that during at least a portion of the time the st ip is on edge, that is to say, the metal extends generally vertically or at least at a suflicient angle to the horizontal to permit draining off of undesirable particles loosened by the pickling solution. By

- spective. of whether the direction of movement of the strip is generally horizontal, generally vertical or at an angle to the horizontal. I prefer, however, to move the strip generally horizontally with the material extending generally vertically during a; substantial portion of the-treatment.

I also treat strip material by moving the same within a treating bath in a substantially horizontally curved path or in a generally spiral path, which may lie either generally horizontally or generally vertically or ,at an angle to the horizontal. This results in an important saving in floor space'as a vat very much smaller in compass than the long vats or series of vats heretofore used for pickling strip metal may be utilized to the same, or, in fact, to better effect, as I make provision for draining off the particles of material loosened from the surfaces of the metal.

I also provide for bringing an instrumentality into contact with successive portions of at least one face of the strip material during treatment.

In the case of pickling strip metal such instrumentality, which may be in the form of a guide roller, assists in separating the particles from the metal, and when the metal is substantially on edge such particles will drop down away from the metal and collect in the bottom of the vat.

I provide for agitating the pickling solution during the pickling operation, resulting in increased efiiciency. This may be done by the movement of the strip itself when the strip is moved in a generally spiral or curved path, as the material does not simply slide substantially frictionlessly through the pickling solution as when moved substantially in astraight line, but tends to cause the solution to swirl and to set up currents therein. Agitation ofthe solution may also be brought about by the use of the instrumentaliparallel'to the material. They act as baifies to cause the solution to move generally transversely with respect to the material. Furthermore, when rotating rolls or rollers are provided in contact with the material these also tend, by reason of their rotation, to impartto the solution a swirling movement. f

Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof proceeds.

In the accompanying drawings I have shown certain present preferred embodiments of the inyention, wherein Figure 1 is a top plan view, with portions cut away, of a continuous pickler;

Figure 2 is a vertical cross-sectional view taken along the line II-II of Figure 1 and showing certain portions of the mechanism which are cut away from Figure 1;

Figure 3 is a vertical cross-sectional view similar to Figure 2 showing a modified construction;

Figure 4 is a vertical cross-sectional view.similar to Figure 2 showing another modified construction;

Figure 5 is an enlarged vertical cross-sectional view through a set of driven feed rolls;

Figure 6 is a horizontal cross-sectional view taken on the line VIVI of Figure 5; and

Figure 7 is a vertical cross-sectional view of a modified form of feed rolls.

Referring more particularly to Figures 1 and 2, there is provided a pickling vat 2 of substantially square cross section in the horizontal direction and which may, for example, be approximately 30 feet on a side. The vat has a sloping bottom 3 adapted to cause material to gravitate to a point 4 where it may be withdrawn laterally. The vat contains a pickling solution 5 which may be of usual characteristics.

There is provided a frame work 6 extending generally across the vat and which may comprise a number of arms radiating from a center, as shown in Figure 1. Mounted in the arms of the frame 6 are a plurality of bearings 1 (see Figures 2 and '7) each carrying in parallel side by side relationship a pair of spindles 8 having integrally connected therewith at their lower portions guiding and feeding rolls 9. Keyed to each spindle at its top is a pinion ID, the two pinions of each set intermeshing. One of the pinions has an upward extension H to which is keyed a pulley I2.

The guiding and feeding rolls 9 are positioned,

as shown in Figures 1 and 2, to guide and feed through the vat in a. generally horizontally extending spiral path strip material fed from a reel l3 by pinch rolls I4. The strip material is withdrawn by pinch rolls l5 and may again be coiled up in any suitable manner.

Certain of the rolls are arranged on an angle, as clearly shown in Figures 1 and 2, to allow of the material being passed through the pinch rolls l4 and I5 which have their axes extending substantially horizontally and to be gradually turned from a horizontal to a vertical position.

The rolls 9 are driven by an endless belt or cable cooperating with the pulleys l2 in well known manner. The endless belt or cable is omitted from the drawings so as not to obscure the more important portions thereof.

Mounted on the frame 6 substantially centrally thereof is a bearing l6 carrying a vertically extending shaft I! which has keyed to its upper portion a bevel gear I 8. Rigidly fastened to the lower portion of the shaft I1 is a table l9 formed as a grating having vertical holes l9 therethrough. This table is omitted from Figure 1 for the sake of clearness. Also mounted on the frame 6 is a bearing 20 carrying a horizontal driving shaft 21, to the inner end of which is keyed a bevel pinion 22 meshing with the bevel gear I8 and adapted to drive the same through the driving shaft 2|. This causes rotation of the table l9.

The guiding and feeding rolls 9 are so positioned with respect to the top of the table I9 as to permit the strip metal guided and fed by the rolls 9 to have its lower edge resting upon the top of the table whereby to support the same substantially on edge and assist the rolls 9 in advancing it. The table is rotated at an appropriate rate to assist in advancing the material, although at points there will be some slippage between the material and the table. The principal purpose of the table is to support the material while permitting particles loosened from the surfaces thereof to pass downwardly through the openings l9.

In Figure 3 .is shown a modified form of construction which, although generally similar to that of Figures 1 and 2, substitutes rollers 23 for the table l9, and thus enables doing away with the bearings mounted on the frame 6'. Any desired number of rollers 23 may be provided around the vat, such rollers preferably having their axes extending generally radially from the center of the vat. They are mounted in trunnion bearings 24 carried at the bottom of the vat. The rollers 23 are not driven, but it is not necessary that they should be, particularly when the guiding rolls 9 are driven so that they will also perform a feeding function. In the form of Figure 3 the strip material is fed to and from and advanced through the vat in the same manner as in Figures 1 and 2, but is supported on the rollers 23 instead of .upon the table I9.

The guiding and feeding rollers of Figure 3 are mounted somewhat differently than those of Figure 2. On account of the provision of the table l9 in Figure 2 it is necessary that the bottoms of the rollers themselves closely approach the top of the table and that there be no hearin at the bottom to interfere with the material which extends slightly below the bottoms of the rolls in order to rest upon the table. In the form of Figure 3, however, it is possible to position the rolls intermediate the rollers 23 so that they can be mounted in bearings extending down below the bottoms of the rolls. In the form of Figure 3 frames 25 are provided which are carried by the top frame 6', each frame 25 having connected integrally therewith at its bottnm a bearing 26. Connected with each frame 25 at its top is a bearing 21. Mounted for rotation in the bearings 26 and 21 are two parallel cooperating spindles 28 having reduced upper and lower extremities 29 for cooperation with the bearings. Integral with each spindle 28 is a guiding and feeding roll 39. Keyed to each spindle is a pinion 3|, the respective pinions intermeshing. The upper reduced extremity 29 of one of the spindles is extended and has keyed to it a pulley-32. The pulleys are driven by an endless belt or cable as above described with respect to Figure 1.

In Figure 6 there are diagrammatically illustrated by chain lines guide devices 33 which may or may not be used in conjunction with the frames 25 to insure proper guiding of the strip thereto.

A further modification is shown in Figure 4 which shows a vat 34 similar to the vat 2 and a rotatable table 35 similar to the table l9 and which may or may not be driven. The top frame and the bearing and driving connections, if any, for the table 35 are omitted from Figure 4 for the sake of cleamess. The point intended to be illustrated by this figure is that the strip may be fed to the pickler substantially on edge and need not be fed horizontally as in Figures 2 and 3. Aside from this, the guiding and feed mechanism may be substantially the same as shown in Figure 2, or it may be substituted by that of Figure 3.

The particular embodiments shown in the drawings are simply to indicate various possible ways in which the invention may be carried out,

ferred ways.

in a spiral path extending at an angle to the horizontal. In either of these cases the material would be substantially on edge, as above defined, during a substantial portion of its treatment to enable the particles to gravitate therefrom The generally horizontal spiral is preferred because during by far the greater part of the treatment the material lies substantially on edge and there is little or no probability that particles in undesirable quantities will adhere to the surfaces thereof. The action of the rolls, whether or not they be driven to feed the material, against the surfaces of the material assists in dislodging particles therefrom to permit the same to gravitate directly to the bottom of the vat.

While I have shown and described certain fluid while substantially on edge, and bringing.

an instrumentality into contact with successive portions of at least one face of the strip throughout the full width thereof during said treatment to remove material adhering thereto.

2. A method of cleaning strip metal, comprising drawing the same lengthwise within and substantially entirely beneath the surface. of a cleaning bath while substantially on edge and with the strip unconfined at its lower edge to permit material removed from the strip to drop away therefrom.

3. A method of treating strip metal, comprising drawing strip lengthwise within a treating bath in a substantially horizontal path having portions lying substantially alongside one another whereby to reduce the length of the space required for the treatment.

4. A method of treating strip'metal, compris-' on edge whereby to reduce the length ofthe space required for the treatment.

7. A method of cleaning strip material, com prising passing the same through a cleaning bath and moving the same while within said bath in a generally spiral path with the successive portions thereof out of contact with one another and substantially on edge.

8. A method of cleaning strip metal, comprising moving the same within a cleaning bath while substantially on edge and bringing an instrumentality into contact with successive portions of at least one face of the strip throughout the full width thereof during said cleaning to remove material adhering thereto.

9. A method of cleaning strip metal, comprising drawing the same lengthwise within a cleaning bath, guiding the same substantially on edge during such movement, and supporting the same at the lower edge thereof but with such lower edge unconfined to permit material removed from the strip to drop away therefrom.

10. A method of treating strip metal, comprising drawing the same lengthwise through a treating bath in a path having at least a portion which is generally spirally curved.

11. A method of cleaning strip metal, comprising drawing the same lengthwise through a cleaning bath while substantially completely submerged in said bath with at least a portion thereof substantially on edge and with the strip unconfined at its lower edge to permit material removed from the strip to drop away therefrom.

12. Apparatus for cleaning strip metal, comprising a cleaning bath, means for drawing strip lengthwise therethrough, and guiding means for the strip so constructed and arranged as to guide the strip substantially on edge and substantially entirely beneath the surface of the bath and with the strip unconfined at its lower edge to permit material removedfrom the strip to drop away therefrom.

13. Apparatus for treating strip metal, comprising a container, means for moving strip through.

said container generally in a spiral with the strip extending generally parallel to the axis of the spiral, and means in said container for treating said strip.

14. Apparatus for treating strip metal, comprising a treating bath, means for drawing strip therethrough, and guide means constructed and arranged to guide the strip substantially on edge and in a curved path having portions lying substantially alongside one another whereby to reduce the length of the space required for the treatment.

15. Apparatus for cleaning strip metal, comprising a cleaning bath, means for drawing strip therethrough, and means for guiding the strip substantially on edge and contacting with successive portions of at least one face of the strip throughout the full width thereof beneath the surface of thebath to remove material adhering thereto.

16. A method of cleaning metal strip, comprising passing the strip continuously through a cleaning bath while substantially on edge and with the strip unconfined at its lower edge to permit material removed from the strip to drop away therefrom. v 17. A method of pickling metal strip, comprising drawing the strip continuously through a bath of pickling acid while substantially on edge.

CARL W. 11mm.

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