US2008736A - Galvanizing device - Google Patents

Description

July^23, 1935. F. cz. WILLIAMS GAQVANIZING DEVICE 1932 2 Sheets-Sheet 1 Filed March 23 l 'l I I INVENT OR. ,W4/vol: C N/1../AHJ

.July 23, 1935. F. c. wgLLlAMs l 2,008,736

I GALVANIZING' DEVICE Filed March 23, 1952 2 Sheets-Sheet 2 INVENTOR. FRANC/S c. w/Ll IAM.:

Patented July 23, 1935 UNITED STATES PATENT OFFICE GALVANIZING DEVICE Francis C. Williams, Detroit, Mich. Application March 23, 1932, Serial No. 600,692

1 Claim.

This invention relates to a metal coating method and device.

The primary object of the invention is the provision of a method of galvanizing iron or other metal articles by immersion through a layer of suitable ux, into a lead bath, and then the withdrawal of the heated article from the metal bath so that the article is passed through a zinc bath, whereby it is coated or galvanized.

Another object of the invention is the provision of a device for the galvanizing of articles by immersion into a metal bath, in which device a receptacle containing a molten metal bath for heating the article, is disposed below a second receptacle, which latter is open at its top and bottom and contains a molten metal bath adapted to adhere to the heated surface of the article, so as to coat said article when the article is withdrawn from the first bath; a recirculating heat interchanging system being provided to maintain the said molten metal at a constant temperature.

Another object of the invention is to provide a galvanizing device including a zinc pot heated by molten lead surrounding the pot, the zinc pot being protected from being burned, and being removable from the molten lead receptacle without necessitating the disassembling of the entire device.

Other objects and advantages are to provide a metal coating method and a device that will be superior in point of simplicity, inexpensiveness of construction, positiveness of operation, and facility and convenience in use and general eiliciency.

In this specification and the annexed drawings, the invention is illustrated in the form considered to be the best, but it is to be understood that the invention is not limited to such form, because it may be embodied in other forms; and it is also to be understood that in and by the claim following the description, it is desired to cover the invention in whatsoever form it may be embodied.

'Ihe invention is clearly illustrated in the accompanying drawings, wherein Fig. l is a sectional View of the entire galvanizing device, including the heat interchange system therefor.

Fig. 2 is a vertical 'sectional view through the heat interchange system, the section being taken on the line 2 2 of Fig. 1.

Fig. 3 is a sectional plan view of the galvanizing elements of the device, the section being taken on the line 3-3 of Fig. 1.

(Cl. Sil-12.5)

Fig. 4 is a diagrammatic view of the arrangement of an indirectly heated zinc pot and the feeding mechanism therein.

Fig. 5 is a sectional view of the feed guides in the zinc pots, the section being taken on the line 5 5 of Fig. 4.

The word galvanizing cation and claim applies or the like articles with coating, metal.

The preferred embodiment of my method of coating articles such as iron plates, piping, beams and the like, includes the following steps; the articles are first immersed into a lead bath through a layer of flux on the top of the lead bath; then the articles are withdrawn from the lead bath, through a bath of molten zinc, which adheres to the heated surfaces of the article and coats the same.

In other words, before the article is introduced into the molten lead it is passed through a layer of suitable flux, and when wthdrawn from the molten lead, it is passed through molten zinc.

The device for carrying out this method includes a tank 6 for the molten lead, a zinc pot I extended into an enlarged top 8 of the tank 6, and a heat interchanging system 9 to heat the tank 6 and the enlarged top 8.

The tank 6 in this illustration is of circular cross section and forms a long, tubular receptacle, closed at its bottom; but the tank may be made of any suitable shape and size, such as a rectangular tank or the like.

'Ihe enlarged box top 8 is open at the its top and has rails I I extended across its top. 'Ihe zinc pot 'l has iianges I2 on the top thereof, which carry rollers I3 to ride on the rails II. The pot l is a cylindrical metal casing, and has a cylindrical lining I 4 on its inner periphery to protect the pot against erosion, and prolong the life of the zinc pot. The pot l is thus suspended on the rails II. To the top of the pot 'l are connected the ends of a cable I6 oppositely to each other. The cable I6 extends around a sheave I1 at any end of the rails II. At the other end of the rail I I is an electric motor I8 to drive a pulley I9 around which the cable I6 extends. A transmission mechanism is provided to connect the driving pulley I9 to the motor I8 at will, so as to be rotated in a desired direction. The pulley I 9 drives the cable I6 so as to move the pot I on the rails II into and out of registry with the lead tank 6.

The tank 6 and the enlarged tank top 8 contain as used in this specito the coating of iron zinc or the like metal by immersion into a molten bath of that the molten lead. The top level of the lead bath is below the rim of the enlarged top box 1. In the space above the lead level is a layer of suitable Y iiux through which the article must be passed bethe top 8 and tank 6. Then the pulley I9 is roV tated in clockwise direction, viewing Fig. 1, so as to cause the cable I6 to pull the pot 1 into position in registry wtih the tank 6. Next a suitable gripping apparatus is lowered through the pot 1 into the tank 6, whereby the heated article is gripped and pulled out of the lead bath and through the Zinc bath.

It is to be noted that the molten lead surrounding the zinc pot 1 maintains the same at suitable temperature without any danger of burning the ot 1. p The specific gravity of molten zinc is lighter than that of lead, hence the molten zinc remains on the top of the lead, but a layer of dross collects in the lower end of the pot 1. The zinc level is spaced below the rim of the pot 1.

The tank containing the lead is heated directly by a heating medium circulated around its outer periphery. Around the tank 6V and the top box 8 are built heat insulating walls 2l spaced from the tank 6 and box 8. The tank 8 and walls 2lI rest on a foundation 22. The top of the zinc pot 8 is supported on the rails I l, in the manner heretofore set forth. Vertical bars 23 and 24 extend alongside the outer periphery of the tank 6 to reinforce the same and also to divide the space around the tank 6 into four substantially equal passages 26, 21, 28 and 29, each of the passages being of a quarter sector cross section. 'I'he bars 23 and 24 have their lower ends cut away as at 3 I, to allow the passing of the heating medium therebelow. A Wall on one side of the top box 8 has an opening, which is divided by a horizontal partition 32, into an inlet 33 above the partition 32 and an outlet 34 below the partition 32. The partition wall 32 extends around the adjacent half of the periphery of the top box 8 so as to cover the top of the passages 28 and 29. VThe bars I4 are extended up to the said partition 32, thereby to form an outlet chamber 36 opposite the outlet 34 and at the upper ends of the passages 28 and 29. p

A vertical bar 31 is disposed alongside the farther side of the top box 8 in an offset plane relatively to the outer bar 23. The bar 31 extends the full length of the box 8 thereby separating the space thereat into passages 38 and 39 communi'cating respectively with the passages 26 and 21.

The heating medium such asgases of combustion is introduced through the inlet 33 and is then circulated downwardly through the passages 38 and 39 and through the parallel passages 2B and 21. The heating medium is then drawn through the passages below the short ends 3| of the bars 24 and upwardly through the passages 28 and 29 into the outlet chamber 36 and out through the passages 28 and 29 into the outlet chamber 36 and out through the outlet 34. Dur-- ing this circulation of the heating medium the same gives up a certain portion of its heat to the Walls of the box 8 and of the tank 6.

In order to maintain the tank 6 and box 8 at a constant temperature, the recirculating furnace 9 is provided. A combustion chamber 43 is disposed below the level of the inlet 33. Into this chamber 43 is introduced and burned the fuel through a usual burner disposed in aperture 44 in the front end of the chamber. Around the chamber 43 and parallel therewith is formed a return duct 46 into which a portion of the spent gases of combustion are returned'to be reheated by the radiating heat vof the walls of the combustion chamber 43. The spent gases are recirculated by means of a fan or blower 41 discharging into the duct 46. The intake end of the blower 41 is connected by means of a duct 4 8 to the outlet 34 to receive the spent gases therefrom. To the pressure side of the'fan 41 is connected a suitable regulable outlet flue, not shown, to release a determined amount of the speniI gases, in such proportion that the additional heat supplied by the replacement of the released spent gases raises the temperature of the recirculated spent gases by the amount of heat conveyed to the tank 6 and box 8, or otherwise consumed.

The return duct 46 discharges into a mixing chamber 49 opposite the inlet opening 33. The discharge end of the return duct 46 is so located that it creates a suction at the discharge opening 5l of the combustion chamber 43 thereby creating a suitable draft to draw from the combustion chamber only the required amount of fresh gases of combustion, thereby regulating the air intake and combustion in the chamber 43.

The returned and fresh'gases of combustion are completely mixed in the mixing chamber 49 and are circulated around the box 8 and tank 6, in the manner heretofore set forth. The circulation and recirculation is effected by the action of the blower 41.

In some instances the articles to be galvanized are not immersed in the lead bath, but the molten lead is used merely to heat the zinc pot. When so used, the zinc pot is provided with a iiux box through which the article is passed before its immersion into the zinc. Such arrangement of my invention is illustrated in Fig. 4.

A zinc pot 52, open at its top and bottom, is extended into the tank 53, so that the top of the pot 52 is supported on the top of the tank 53, and the sides of the pot 52 are spaced from the sides of the tank 53. In the space between the pot 52 and the tank 53 is molten lead for heating the pot 52.

The pot 52 is lled with molten zinc. A layer of dross usually collects in the bottom end of the pot 52. The articles are passed through the pot 52 by means of feed rollers 54 and guide rails 56. .Each set of guide rails 56 includes a pair of opposed plates 51 spaced from each other in such manner as to easily accommodate the sheets of iron or the like therebetween. The feedingof the article through the zinc is continuous and in the same direction. The inlet end of each guide rail 56 is flared to form a wide mouth. Then the plates 51 are convergent toward the set of feed rollers 54 adjacent the other end of the said rail 56. The number of sections or rails 56, and the roller 54 are determined ac cording to requirements. 'Ihe rails 56 are so curved as to form a continuous path from one end down into the zinc and then out of the zinc at the opposite end or side of the pot 52. The rails 56 are supported in the pot 52 on suitable support bars 58.

Around the intake end of the rst intake rail 56 is formed a ux box 59 mounted on the inside of the pot 52. This box 59 contains suitable flux, through which the articles are passed before they are immersed into the molten zinc. The box 59 as well as the zinc pot 52, is lined on the inside. An outer intake feed roller 6| below a guide 62 directs the sheet metal, or like article, to the mouth of the iirst rail 56 in the flux box 595 It is to be noted that the rails 56 are comparatively narrow strips so as to allow the molten zinc to freely contact with the entire surface of the article to be galvanized.

In some instances, the bottom of the pot 52 may be also covered. 'I'he lead tank 53 is heated around its outer periphery in the manner described in connection with the first described.

embodiment of my invention. A

Having thus described this invention, what I claim and desire to secure by Letters Patent is:

In a device of the character dcscribed,.a receptacle containing a molten metal which does not adhere to the surface of an article to be galvanized; a second receptacle open at its top and bottom inserted in the top of the first receptacle and containing a molten metal which adheres to the surface of said article after the article is heated, thereby coating the same, the non-adhering molten metal being of higher specific gravity than that of the molten metal in the second receptacle; heat interchanging means to maintain the iirst receptacle at a constant operative temperature, comprising a heat inlet adjacent the upper end of/the rst receptacle; a vertically disposed baille extended substantially the entire length of the outside of the iirst receptacle on diametrically opposite sides thereof; and a heat outlet adjacent the heat inlet.

FRANCIS c. wILuAMs.

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