US1324220A - Galvanizing process - Google Patents

Description

E. L. WATROUS. GALVANIZING PROCESS. APPLICATION FILED OCT. 1. I917.

Patented Dec. 9, 1919.

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Specification of Letters Eatent.

Patented Dec. e, rte-re.

Application filed October \1, 1917. Serial No. 194,104.

To all whom it may concern:

Be it known that I, EDWARD L. WATROUS,

a citizen of the United States, residing at tion.

This invention relates to galvanizing processes and particularly to a process for simplifying and rendering more efiicient and cheaper the galvanizing of small articles such as bolts, nails'or the like, although the invention in its main features is also applicable to any formof galvanizing. The ordinary process, of galvanizing consists in providing a vat of moltenj spelter into which the articles to be galvanized are dipped. It is necessary to cover the articles to be galvanized prior totheir being put into the molten spelter with a coat of sal ammoniac, muriate of zinc, or some other similar substance to act as a flux. In the commercial process of galvanizing heretofore carried out, a vat of molten spelter is provided upon the top of which floats a layer of the flux employed. The articles to be galvanizedare introduced into the molten spelter through the flux, picking up the coat of flux as they pass through this material. When the vat is charged, a portionof the flux' is skimmed ofi the top of the spelter and the coated articles removed from the spelter through theopenmg thus made.

This process is open to serious objections,

although it is the most eflicientv and simplest heretofore developed. In the -first place, the placing of the flux on top of'the rmalten spelter causes a very rapid evaporation, and a consequent high loss ofthe flux. Again the operation of skimming off the flux to make an opening through which ,to withdraw the articles consumes considerable time and labor, and must be carefully done. Another objection to this process is the fact that the articles to be introduced into the spelter cold extract from the spelter, which has a comparatively low specific, heat, a large quantity of its heat, which, chills the spelter to such'a deg'reethat notonly must the work be frequently interrupted to permit the spelter to warm up to the required temperature, but very; hard firi dered' necessary to keep 1 is rem" the operation going.

at all successfully, and the articles to be coated do not get a thin, uniform coat. This firing rapidly burns out the spelter vats, and, of course, is expensive and requires additional labor.

Furthermore, it is obvious that under the process just described, the articles must remain in the spelter until every part thereof has reached the temperature of the spelter, notwithstanding the. fact that certain parts of the articlemay long prior to that time have reached the required temperature and received sufiicient coat. This again introduces the time-consuming factor, and furthermore, is responsible for unsatisfactory galvanizing, because the longer the articles remain in the spelter the heavierthe coat placed upon them, and if certain parts of the articles take longer to reach the required temperature than other parts, the coat upon the articles will be uneven and upon the more rapidly coated parts there will be lumps or e'xcrescences of zinc. This, in addition 'to consuming a large amount of extra spelter, involving an extra expense, is furthermore objectionable because a thick coating or lump of spelter on any article is apt to chip or crack ofi', taking wlth it the superficial coat as Well, rendering the articles liable to rust, and furthermore, clogs the screw: threads and other fine points, rendering special machining necessary, in many instances after the articles have been galvanized, which machining at some point or other goes through the, coat of zinc, again introducing the. liability to rust. The desideratum in galvanizing is a uniform completely covering'the article but as thin as practicable, a very thin coat being amply suflicient to prevent rust, and from all standpoints ,being the most satisfactory and the mostperfect, because most thoroughly united to the article.

'The most valuable function of this invention is in 'treatin small articles like 'nails, tacks, screws, rlvets, washers, small otherwise the flux would be burned off, oxi dation would take place and the work would -not coat. This being the case the introduction of a mass of colder metal chills the zinc and it solidifies around the outside of the mass, leaving the center untouched. The whole mass often rises and floats on the surface, as cold zinc'is lighter than hot, thus exposing still less surface to the heat. As the mass gradually warms up, the zinc gradually melts and flows" into the center, but is constantly chilled and retarded as 1t meets new cold metal. The longer the work stays in the bath, the heavier coat it takes on, so, that by the outside articles have taken too heavy a coating and will be rough and scaly, while if the basket is lifted as soon as the outside articles are ready, the center will still be black and uncoated.

Among-the objects of my invention, therefore, is to provide a process which wlll greatly increase the elficiency of galvanizlng small articles such as bolts, nails, or ,the like; 1

further to render the process of galvanizing cheaper and more simpleyfurther to make possible the application of a thin, uniform coating to the articles to be galvanized whereby they will be substantially free from lumps of spelter or too thick a coating, thus reducin to the minimum the danger of portions 0? the coating chipp o'fl and leaving the article llable to rust; also eliminating1 the danger of lumps of spelter the galvanizing;

threads in the case of clogging t e screw like, thus removing the bolts, screws, or,the

necessity of using spec al machinery to go over such threads after galvanizing; further to reduce the time necessary for the articles to remain in the in a much neater and smoother product of and such further objects and advantages as-will later become more readily apparent.

y improved process is hereinafter -ex plained in connection with the annexed drawing,

view of a galvanizing tank for carrying out my process.

Fig. 2 shows an elevation partly broken of the galvanizing tank shown in Fig. 1.

.Fig. 3 shows a vertical section ofa flux Fig. 4 shows an elevation of a centrifugal machine for removing excess material from galvanizcd articles. My invention contemplates treating the articles to be galyanized by first covering them with a heavy coat ing them in flux F in tank T, sal ammoniac being the most practicable, (however, I-may use other kinds of flux if desired,) and then drying them to such a remains. Any cons derable quantity of moisture would cause an explosion when the work is poured into the bath. The best 1 practice isto then heat the articles coated the time the center is ready,

ing or cracking spelter; further to resultin which Figure 1 shows a plan of fiux,.as by pl'ac it is hardly perceptible.

point that no moisture with flux to as high a degree as possible without driving off the flux, although fair results may be obtained with work that has been allowed to cool. after drying. A suitable empty basket or dipper B is then submerged in ,the zinc bath Z in galvanizing bath V and the work on the surface of the zinc inside the basket. The particles being well scattered, as by means of flaring spout S, no one of them exterts much chilling effect upon the zinc and each one will almost immediately take the coating and sink. 2 Should too many of the particles fall together and form a conglomerate, this will be small and the operator can quickly slice it under the surface with a few strokes of the skimmer. As soon as the last article is under the surface, the surface 'of the zinc should 'be quickly skimmed and the receptacle lifted and agitated, as by rotating or the like, to throw off the surplus metal. One form of such agitating means is shown in my Patent No. 1,221,397, granted April 3, 1917, as shown in elevation in Fig. 4 of the present draw- 1ng. 1

This may be varied by using a flux blanket on top of the kettle, lowering the empty basket through the flux andthen pouring the articles to be galvanized into the basket through the flux blanket on the surface of the metal. In using this-method, it is not so necessary to have the work dry, and in fact, it may come from the pickling tank quite wet and does not need to be previously fiuxed.

The best results, however, will be obtained when the work has been prefluxed and preheated. Of course, all these methods presume that the work has been previously cleaned, by pickling or other methods.

The main part of my invention, lies in thepouring or sprinkling of the work upon the surface of the metal thus scattering the articles to be coated instead of introducing them in a massl' By pouring? Imean v allowing the articles to escape slowly from a container and drop into the galvanizing vat, substantially out of contact with each 0 er, so that freezing is prevented. This may be directly from the container to the vat or from the container to a spreading chute and thence to'the vat.

Articles treated by this method will take on a coat, which, whileheavy stand several times the United States Governmen t test for galvanization, is sosmooth enough to poured or sprinkled and clean and uniform that m measurement Nuts, may be turned upon bolts without recutting' the threads, machined pieces will fit together without being recut, and in short, the finest possible results are obtained with a minimum cost for, spelter, labor, flux and fuel, so that the cost of this fine work is only restate "from one-half to one-third of that of the ordinary rough work.

Having now described my invention,

I clainit- 1. The process of galvanizing which consists in first submerging in a bath of molten zinc an empty perforated basket or other receptacle and then sprinkling or pouring upon the surface of the zinc, inside the basket, the previously fluxed articles to be gal vanized, then removing the receptacle and the work contained therein and agitating the same to remove the surplus zinc.

2, The process of galvanizing, which consists of submerging in a bath of molten zinc a perforated basket or other receptacle, then covering the surface of the zinc 'with a blanket of flux, then pouring or sprinkling into the receptacle, through the flux, the articles to be galvanized, skimming ofi the flux, removing from the zinc bath the receptacle and the work contained therein and agitating the same to remove the surplus zinc.

3. The process of galvanizing which consists in pouring or sprinkling the articles to be coated upon the surface of a bath of molten zinc,-and permitting the force of gravity to separate the articles which have been coated from those which have nottaken a coat, whereby to cause the fresh hot zinc to have access to the uncoated portions. v

4. The method of-galvanizing which consists in'scattering in a substantially separated condition the articles to be coated, upon the surface of a bath of molten zinc, permitting each article which has been coated to sink as soon as it takes its coat, where' submerging a per orated basket in said bath,

the uncoated articles floating upon the surface of thebath will be readily acces-- sible to the fresh hot metal of the bath and in turn quickly take their coat and sink..

5. The process of galvanizing which consists in submerging a perforated receptacle in a bath of molten zinc, coating with flux the articles to be galvanized, sprinkling or scattering said articles upon the surface ofthe zinc inside the receptacle, removing the receptacle with its contents, and then removing the surplus coating from said articles by centrifugal force.

6. The process of galvanizing which consists in providin a bath of molten zinc,

covering the surface of said zinc with a blanket of flux, pouring or sprinkling the articles to be coated into said basket and through the blanket of flux, removing the basket from said bath, and then removing the surplus zinc from the articles in said basket by centrifugal force.

7. The process of galvanizing which consists in covering with a flux the articles to be coated, and then heating said articles, pouring or sprinkling said articles into a perforated receptacle submerged in a bath of molten zinc, removing the receptacle from said bath, and agitating said receptacle to remove the surplus zinc from said articles therein.

8. The process of galvanizing which consists in providing a bath of molten zinc, submerging a perforated basket in said bath, covering the surface of said zinc with. 'a blanket of flux, preheating the'articles to be coated and then pouring or sprinkling them through the flux blanket into the zinc in said basket, removing the basket from said bath, and then removing the surplus zinc from the articles in said basket by centrifugal force.

9. The process of galvanizing, which consists of submerging in a bath of molten zinc a perforated basket or other receptacle, then covering the surface of the zinc with a blanket of flux, then pouring or sprinkling into the receptacle, through the flux, the articles to be galvanized, skimming ofi the flux, removing from the zinc the receptacle and the work contained therein, and sub:

jecting the same to centrifugal action to remove the surplus zinc.

10. That step in the pr ing which consists in sprinkling the articles to be galvanized upon the molten galvanizing mass.

11. The improvement in the art of galvanizing which consists in scattering the articles to be galvanized upon the surface of the molten galvanizing mass in a perforated container submerged in said galvanizmg mass.

In witnesswhereof, I hereunto subscribe my name to this specification in the presence of two witnesses.

, EDWARD LAG-EY WATROUS. Witnesses:

F. H. Sammns, T. M. QUEBEDEAUK,

ocess of galvaniz-

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