US3721520A - Galvanizing wire - Google Patents

Abstract

The invention relates to galvanizing of wire and shows the direct heating of the wire in such a manner that it is protected from oxidation prior to delivery to a galvanizing pot.

Description

United States Patent 11 1 Bloom ]March 20, 1973 [54] GALVANIZING WIRE 21991389 7/1961 Martin 4563/3 3,355,156 11/1967 Hanna ..263/3 [751 'Y Dreshe" 3,183,605 5/1965 Argue et a1 ..263/3 Assignee: Corporation of Amer Crapo 1 17/5 1 masher, p 3,010,344 11/1961 Klein et a1. ....117/51 2,570,906 10/1951 Alferieff ..1 17/51 [22] Filed: Sept. 2, 1971 [21] App1.N0.: 177,417 Pn'mary Examiner-John J. Camby Assistant Examiner-Henry Yuen Related [1.8. Application Data went-0rd Mason [62] Division of Ser. No. 750,338, Aug. 5, 1968, abandoned. [57] ABSTRACT H The invention relates to galvanizing of wire and shows [52] us Cl "432/143 432/8 432 7 the direct heating of the wire in such a manner that it [511 1111.0; ..'....I.1.1..L..TLL.Ii.Ti7E9/2B" s Protected from oxidation Prior to delivery to a [58] Field of Search ..263/3; 266/3 mums [56] References Cited 4 C 3 Drawing figures UNITED STATES PATENTS 3,510,113 5/1970 Wise "263/5 PATENTEDNARZOIEIYS 3,721,520

FIG.2

FIG. I

INVENTOR. QUENTIN M. BLOOM GALVANIZING WIRE This is a division, of application Ser. No. 750,338 filed Aug. 5, 1968, now abandoned.

SUMMARY OF THE INVENTION The present invention relates to galvanizing and more particularly to a method and apparatus for the continuous galvanizing of a strand such as wire, a web or the like.

In order to obtain a tight coating of zinc on a base of ferrous metal, great care must be used to see that the metal to be coated is clean and free from any oxide. This usually requires heating in a muffle or atmosphere furnace of some type after the base metal has been thoroughly cleaned.

According to the present invention, the wire or other strand or web to be galvanized is heated directly in a flame supplied with fuel and air in such a ratio that the wire is cleaned as it is being heated. The flame is produced by a novel burner that is built into a tube through which the strand is moved.

It is an object of the invention to provide a method for the continuous galvanizing of wire or other strand or web by directly heating the wire in a flame as it is being delivered to a galvanizing tank.

It is a further object of the invention to provide a novel apparatus for heating wire for galvanizing or other purposes.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a preferred embodiment of the invention.

IN THE DRAWINGS FIG. 1 is a view of the apparatus used in carrying out the method,

FIG. 2 is a section view of one of the heating units, and

FIG. 3 is a view taken on line 3-3 of FIG. 2.

Referring to FIG. 1, the wire W to be galvanized is moved axially through heating units 1 and 2 into and through a cooling or holding unit 3. Unit 3 is provided with a guide roll 4 around which the wire moves through a chute 5 into a galvanizing pot 6. This pot is provided with a roll 7 around which the wire travels so that it leaves the pot in a vertical direction to any desired subsequent treatment or to storage. The unit 3 is provided with openings 8 and 9 which are aligned with the travel of the wire as it approaches and leaves the roll 4. These openings are normally closed but can be opened to facilitate threading the wire around the roll.

The heating units 1 and 2 are the same except that they are shown in FIG. 1 as being reversed in direction. The construction of these units is shown in FIG. 2. Each unit includes a pipe 11 which forms a combustion chamber 12, the ends of which are closed by walls 13 and 14 respectively. The wall 13 has an axial opening in it in which is inserted a sleeve 15 forming an entrance for the wire into the chamber, and an exit sleeve 16 is attached around an opening in the other end 14 of the chamber. As shown in FIG. 1, exit sleeve 16 connects with heating unit 2 to form the entrance sleeve there.

Fuel. preferably in the form of a combustible gas, is introduced into sleeve 15 through pipe 17. While one supply pipe 17 may be used, several are shown herein in order to get a more even distribution of fuel around the wire. The fuel then flows through sleeve 15 and into the chamber 12. This chamber has a shell 18 encircling it to form an annular air space 19. Combustion air is introduced into the space 19 at the end opposite the entrance end of the fuel and moves through the space and through openings 22 into combustion chamber 12. Some air passes through openings 23 in sleeve 15 for preliminary mixing with the fuel. The inner end of sleeve 15 is provided with a radially extending disc or flange 25 which serves to create turbulence in the incoming air as described below. The products of combustion produced by the burning of fuel and air in chamber 12 are discharged through an exhaust pipe 26 which extends from sleeve 16. The products of combustion produced in both of the heating units 1 and 2 will flow to the sleeve 16 and be exhausted through the single exhaust pipe 26.

ln'order to insure that no oxidation of the wire will take place as it is being supplied to the combustion chamber, the wire W is introduced into chamber 12 through a tube 27 which is attached to and extends coaxially of sleeve 15. During the operation of the apparatus a reducing gas such as hydrogen is introduced into tube 27 through a pipe 28. It is noted that the tube 27 between heating unit 2 and cooling unit 3 also permits the reducing atmosphere from supply pipe 28 to flow into the unit 3, thereby creating an atmosphere that will prevent contamination of the surface of the wire after it has been heated. Additional atmosphere can also be introduced directly into unit 3 and chute 5 if desired.

In the operation of the system, the wire is moved continually through units 1, 2, and 3 and into zinc pot 6. Gas and air are supplied to the end of units 1 and 2 as shown in FIG. 2, with the construction of the left end of that figure being in effect, a burner which surrounds the wire. A small quantity of air flows through the openings 23 to mix with the gas, giving a premix with the final mixture taking place with air flowing through openings 22 around disc 25 to mix with the remainder of the gas and the air exiting from sleeve 15. The turbulance created by this construction produces an excellent mixing of the fuel and air so that they will burn in a flame which entirely surrounds the wire, heating the wire to a temperature depending upon the speed and diameter of the wire. Air flowing to the burner through annular air space 19 will serve to cool the wall of pipe 11 sufficiently to prevent damage to this wall while, at the same time, the air will be preheated. Air flowing radially inwardly through openings 23 would normally cause oxidation of heated wire by free oxygen. This is prevented by having the wire travel through tube 27 that is supplied with a reducing gas, such as hydrogen. Tube 27 extends beyond the point of complete mixing of the gas and air and into the flame. The hydrogen will also be burned where it leaves tube 27.

The ratio of the gas and air supplied to the burner will be such that the products of combustion will contain no free oxygen and will have from l-6 percent combustibles. When products of combustion of this composition are above about 2100 F and the metal being heated is below about 1700 F, the atmosphere will have a reducing effect and will clean an oxide film from its surface. Therefore, the wire, as it is moving through heating heating units 1 and 2, will be cleaned of any coating thereon and this clean surface will be maintained by the atmosphere in unit 3 while the wire is traveling through this unit and through chute 5 into the zinc in pot 6 below the metal line.

The temperature to which the wire is heated will de pend upon a number of things. In particular, it will depend upon the diameter of the wire and its speed. With a pair of heating units, each of which is 10 feet long, a 12 gage wire can be heated to annealing temperature at a speed of about 90 feet per minute. If the wire is to be moved faster, additional heating units can be placed around the path of the wire to duplicate the arrangement of the heating units shown in FIG. 1. Sometimes it is desirable to anneal the wire immediately prior to the time that it is galvanized in a continuous process. If this is the case the wire will be heated to an annealing temperature of about 1300 F. From this temperature it must be cooled to about the temperature of the galvanizing pot which is normally 850 F, before it is moved into the pot. In such a case, unit 3 will act as a cooling chamber and may be cooled by having water from a spray 29 flow over it to bring the temperature of the wire down to the desired degree. At other times when the wire may previously have been annealed, or is to retain as-drawn properties, it will be desired to heat the wire only to within a 100 or so of the galvanizing temperature. In this case, chamber 3 would act as a holding chamber to keep the wire at the proper temperature before it goes into zinc.

From the above it will be seen that l have provided apparatus for continuously-galvanizing wire in which the wire is heated and simultaneously cleaned by a flame that burns entirely around the wire and in direct contact therewith. The method followed requires a minimum amount of equipment that is rugged and relatively inexpensive to build. While the drawings show only a single strand of wire moving through the heating units, it is possible to move two or three strands through each unit if they are properly guided to keep them separate as they travel therethrough. Where a large number of strands are to be galvanized, as is usually the case, several of the units would be placed side by side so that a single zinc pot can be used for simultaneously galvanizing a plurality of wires.

In the above description, wire has been shown as the material being galvanized since the apparatus is particularly adapted for that material. It will be apparent, however, by a mere change in cross-section shape of the apparatus it could be used for galvanizing a strip. The apparatus in its present form can be used for heating a rigid body such as a pipe for galvanizing. Obviously, the equipment can be used for coating wire with other metals, such as aluminum.

While in accordance with the provisions of the Statutes l have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. Apparatus for heating a metal strand for galvanizing and the like comprising means forming an elongated cylindrical chamber closed at both ends, means forming openings in said ends through which the strand passes axially into and out of said chamber, means to supply fuel to one of said openings around thestrand, means to supply air to the end of said chamberthrough which fuel is supplied, the air surrounding the fuel, a shell surrounding said chamber and forming an annular space communicating with the means through which air is supplied to the chamber, and means adjacent to the other end of said chamber through which air is supplied to said space.

2. The combination of claim 1 in which the means to supply fuel to the chamber includes a sleeve extending axially through said opening into said chamber, the strand also entering the chamber through said sleeve.

3. The combination of claim 2 including means on the end of said sleeve in said chamber to create turbulence in the air entering the chamber thereby to help mixing of the fuel and air.

4. The combination of claim 2 including a tube smaller in diameter than said sleeve and mounted axially therein, the strand passing into the chamber through said sleeve, said tube being of a length to extend beyond both ends of said sleeve.

Claims (4)

1. Apparatus for heating a metal strand for galvanizing and the like comprising means forming an elongated cylindrical chamber closed at both ends, means forming openings in said ends through which the strand passes axially into and out of said chamber, means to supply fuel to one of said openings around the strand, means to supply air to the end of said chamber through which fuel is supplied, the air surrounding the fuel, a shell surrounding said chamber and forming an annular space communicating with the means through which air is supplied to the chamber, and means adjacent to the other end of said chamber through which air is supplied to said space.

2. The combination of claim 1 in which the means to supply fuel to the chamber includes a sleeve extending axially through said opening into said chamber, the strand also entering the chamber through said sleeve.

3. The combination of claim 2 including means on the end of said sleeve in said chamber to crEate turbulence in the air entering the chamber thereby to help mixing of the fuel and air.

4. The combination of claim 2 including a tube smaller in diameter than said sleeve and mounted axially therein, the strand passing into the chamber through said sleeve, said tube being of a length to extend beyond both ends of said sleeve.

Images