US244153A - Manufacture of galvanized iron - Google Patents

Description

(No Model.)

W. B. SPEAR. MANUFAUTURE OF GALVANIZ-ED IRON.

No. 244,153. Patented July 12,1881.

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UNITED STATES PATENT OFFICE.

WIOKHAM B. SPEAR, OF PHILADELPHIA, PENNSYLVANIA.

MANUFACTURE OF GALVANIZED IRON.

SPECIFICATION forming part of Letters Patent No. 244,153, dated July 12, 1881.

Application filed May 10, 1880. (No model,)

To all whom it may concern:

Beit known that I, WioKHAu B. SPEAR, of`

the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in the Manufacture of Galvanized Iron, of which improve,- ments the following is a specification.

The objects of my invention are to economize time, labor, and material in the manufacture of galvanized iron, and to produce a better and more highly finished product; to which ends my improvements consist in a novel apparatus, as hereinafter fully set forth.

To enable others skilled in the art to practice my invention, I describe the same with reference to the accompanying drawings, in which- Figure 1 is a vertical longitudinal central section through an apparatus for galvanizing iron in accordance with my invention, and Figs. 2 and 3 are, respectively', vertical longitudinal vertical and transverse sections, each on an enlarged scale, through the zinc-tank.

A necessary preliminary to the practice of my invention, as to that of all other galvanizing processes with which in my experience as a. manufacturer I have become familiar, is the removal of the scale or oxide from the sheets to be treated, which removal is ordinarily effected by immersion in a bath of sulphuric acid and water. As an alternative and preferable method of pickling the sheets, they may be placed in a tank containing a solution of sulphate of soda or potash, oil of vitriol, or commercial sulphuric acid and water, as I have found the surface of the iron to be in better condition after being cleaned by the use of such mixture than if a simple solution of sulphuric acid had been employed. After the sheets have been pickled they are removed from the bath and placed in a tank of water, from which they are removed, one at a time, and examined, and any particles of scale that may remain are removed by the use of a triangular scraper. Assumng either of the above methods to have been adopted, I take the sheets of iron which have been pickled in the vat A and immerse them in a tank or vat, B, of lime-water, for the purpose of neutralizing the action of the acid upon the iron, and preventing the corrosion or pitting of the latter thereby. In cases where the scale has been removed from the sheets by processes other than those involving the use of acid, as by abrasion or analogous means, the subsequent treatment with lime-water will be unnecessary, and is therefore dispensed with. I next pass the sheets to a tank, G, containing water, within which are placed a series of revolving brushes, C', preferably formed of rubber sections divided radially, so as to present toothed or serrated peripheries, between which brushes the sheet traverses below the surface of the water in the tank, the rubbing action of the brushes being exerted upon each side of the sheet, with the effect of removing therefrom any accumulated deposit which may have settled thereon in the rolling of the sheet, or in its immersion in the acid and lime-water baths, and providing a clean and perfect surface for the deposition of the zinc. The sur plus water is removed from the sheets` by passing them between gum rolls C2 at'the outlet or delivery end of the tank. The sheets are next passed from the rolls C2 to a tank, D, and traversed, between carrying-rolls d therein, through a bath of a strong solution of chloride of zinc of, say, 300 to 360 specific gravity, the purpose of which is to prepare their surfaces for the reception of the zine coating. A bath of dilute muriatic acid may, if preferred, be used in the tank D, in lieu of the solution of chloride of zinc. After passing through the tank D the surplus solution is removed from the sheets by passing them between gum rolls d', from which they pass to a drying-oven, E, which is composed of sheet-iron, and, by preference, heated by steam-pipes c, the sheets being traversed through the oven between iron carrying-rolls E. The steam for heating the oven E may with advantage be superheated by means of a furnace, E2, or by appliances connected with the boiler in which it is generated. The sheets are discharged from the drying-oven E, through rolls E3,into a tank or vat, F, filled with zinc, which is maintained in a molten condition by the application of heat around the tank, the sheets entering the tank in a vertical direction, into which they are deflected by the feed and guide rolls f, and passing into the molten zinc through a stratum'of chloride of zinc derived from a body of sal-ammoniac, which covers and floats upon the sur- IOO face of the molten zinc, upon one side of a division-plate, f, extending across the vat F. The insertion and removal of the sheets vertically on opposite sides of the division-plate prevents the sal-ammoniac or resultant chlo ride of zinc from coming to the surface of the bath with the iron and staining the surfaces of the sheets, as is otherwise frequently the case. The use of sal-ammoniac or chloride of zinc in the tank Fis not an essential 5 but I have found in practice its employment to be advantageous, and therefore recommend it.' From the rolls fthe sheets pass under the surface ofthe molten metal, being directed in their passage through the same by curved guides f2, and are discharged from the tank in a finished condition by the delivery-rollsf3.

By the employment of the feeding and delivery rolls and the curved guides the sheets may be passed, one by one, from the dryingoven directly to and through the Zinc-tank, as rapidly as is consistent with the proper deposition of the zinc coating upon their surfaces.

The labor required for handling the sheets in the manner heretofore usually practiced is economized, and the delivery of the sheets from the zinc-bath between the rolls insures better finish and greater uniformity of coating than are obtainable when th e sheets are inserted and removed by hooks or tongs, as is ordinarily the case.

The relative arrangement of the several vats or tanks and thc drying-oven in one connected series is such that the several operations set forth can be consecutively and continuously performed, and the speed of the dierent pairs of rolls, between which the sheets pass in their traverse through the apparatus, should be substantially uniform, so that there may be no tendency to an undue accumulation of the sheets in one portion of the apparatus or delay thereof` in another.

I claim as my invention and desire to secure by Letters Patentl. In an apparatus for galvanizin g sheet-iron, a water-tank provided with aseries of brushes arranged to rotate therein below the waterlevel,combined with an adjoining tank having a series of carrier-rollers rotating below the level of the liquid therein contained, and a pair of intermediate gum rollers located between the two tanks, or at the outlet or delivery end of the tank first named, substantially as set forth.

-2. The combination, in an apparatus for galv`vanizin g sheet-iron, of a water-tank provided with -a series of brushes arranged to rotate therein below the water-level, a tank to receive a solution of chloride of zinc, and having a series of carrier-rolls adapted to rotate below the level of such solution, a dryingoven having internal carrier-rolls, and a tank for containing molten zinc, said tank being provided with guide feed-rolls and a curved guide for governing the direction of sheets o t' iron in passing through it, substantially as set forth.

WICKHAM B. SPEAR. Witnesses:

J. SNowDEN BELL, WM. H. MYERS.

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