US762654A - Method of annealing and tempering forms of metal. - Google Patents

Description

PATENTED JUNE 14, 1904. E. P. REIGHHELM. METHOD OF ANNEALING AND TEMPERING FORMS OF METAL.

APPLICATION FILED AUG.4, 1902.

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i i tejeaesa :.UNITED STATES Patented June 14., 1904.

PATENT OFFIcE.

EDIVARD P. REIOHHELM, OF BAYONNE, NEI/V JERSEY, ASSIGNOR TO AMERICAN GAS FURNACE COMPANY, ELIZABETH, NEIV JERSEY,

A CORPORATION OF NEW JERSEY.

METHOD OF ANNEALING AND TEMPERING FORMS OF METAL.

SPECIFICATION forming part of Letters Patent No. 762,654, dated June 14,1904.

I Application filed August 4, 1902. Serial No. 118,215. (No specimens.)

To all whom it mcty concern:

Be it known that I, EDWARD P. REIOHHELM, a citizen of the United States, residing at Bayonne, in the county of Hudson and State of New Jersey, have invented an Improvement in the Methods of Annealing and Tempering Forms of Metal, of which the following is a specification.

. are usually of smoothly-finished and highly-' My invention relates to a method or process of annealing and tempering strips, bars, tubes, and other forms of metal, especially silver and gold and such other precious and semiprecious metals as do not harden when plunged into a cold bath at an annealing heat.

My present invention is allied to the invention of Letters Patent granted to me March 12, 1901, No. 669,765. In this patent is shown a gas-furnace generally constructed of the form preferred by me and which is adapted for the carrying out of a portion of the present process or method. The apparatus of said patent was adapted to heating strips, bars,

tubes, and other forms of metal for annealing and tempering the same and preparing the same for drawing, stamping, and other treatment in the arts. I have heretofore found it diflieult to prevent these forms of metahwhich polished surfaces, from readily becoming discolored and oxidized uponemerging from the furnace after treatment therein, and I have discovered that if said materials are cooled by p a water-bath before reaching the atmosphere in a bath that is so connected to the heatingchamber that the furnace-gases by their pressure will continue to protect said forms of metal from contact with the atmosphere until v the same are cooled, this discoloration and ing the same to a bath of cooling water prior to said forms of metal being admitted to the influences and pressure of the atmosphere.

In the drawings I have represented forms of apparatus adapted for the carrying out of my improved process or method, in which- Figure 1 is a vertical longitudinal broken section representing a furnace. Fig. 2 is a sectional plan of the parts, Fig. 1, above the series of rolls and at one end of the furnace; and Fig. 3 is a vertical section representing a simplerform of apparatus.

In the apparatus the metal shell or case is preferably composed of a top 1, bottom 2, sides 3, and ends I, secured together in any Well-known manner and supported upon legs 5. The same is provided throughout with a fire-brick lining-6, with a throat 7 at one end for the entrance of the forms of metal to be treated and an exit-throat 8 at the other end. Hollow metal shafts a pass transversely through the furnace in a horizontal plane and at equally-spacedapart intervals, supported by bearing-brackets a outside the case. Surrounding these shafts are rolls 6, preferably composed of fire-brick or graphite and made with annular ribs 6, which are preferably spaced at equal distances apart along the rolls,

and the rolls are all alike. The respective ends of the shafts a are provided with sprockcts 9. These are connected in alternate pairs upon opposite sides of the furnace by chains 10, and power communicated to the wheel 11 on the first shaft is adapted to operate all of the rolls of the series at the same speed and in the same direction.

Burners 0 for gas and air are provided and enter the furnace at suitable points in the opposite sides, preferably below the series of rolls passing through the ire-brick lining. Pipes 0 extend from these burners and connect with pipe-sections (Z, 6, and f. At the exit end of the furnace I provide brackets g,

water under pressure.

supporting rollers h. At this end of the furnace I provide deflector-plates 2' and i, arranged vertically and preferably in parallel planes at opposite ends of the throat 8. Between these deflectorplates are cover-plates k is, the plate In being fixed, secured at one end to the metal end shell 4 and extending upward and outward, with its upper edge in the same plane as the edges of the rollers b and rollers it. The cover-plate k is connected above the throat 8 to the end shell of the furnace by a hinge-joint and hangs freely, so that its lower free edge is adapted to ride or bear upon the upper surfaces of the forms of metal 12, passing th rough the furnace. These cover-plates are advantageously arranged at inclinations of about forty-five degrees.

Tubes 13 and 14, having one or more lines of fine perforations, extend across the end of the furnace above and below the dischargethroat 8 and above and below the cover-plates bk. These tubes are supported in any desired manner and advantageously extend through the deflector-plates 2' vi, the perforations in the pipe 13 being on the under side and in the pipe 14 on the upper side and said pipes connected to any suitable supply of The deflector-plates 2' a" and cover-plates is k substantially close off the exit-throat 8 except when forms of metal are passing through the furnace, and then only the spaces in a horizontal plane between said forms of metal are in evidence.

In the modified form of apparatus shown in Fig. 3, Z represents a furnace having a metal shell and a fire-brick lining mounted upon a water-tank m, provided with an inlet water-pipe 15 and an exit water-pipe 16. There is an opening through the bottom of the furnace and top of the water-tank and an opening through the top of the furnace, and the furnace is provided with pipes 01 n and burners 0 0 for gas and air, and in the drawing a bar or form of metal 17 is shown as suspended within the furnace by a cross-piece setting on top of the furnace. The watertank on is closed except to the aperture extending to the furnace, and the opening in the upper part of the furnace provides for the entrance of forms of metal and the escape of surplus pressure of gases from within.

In carrying out the process or method and with reference to Fig. 3, which shows the simpler form of apparatus, a bar or form of metal is suspended within the furnace and is heated by the gas and air flames from the burners 0 0 until the same is brought to the desired temperature for annealing and tempering. When this point is reached and in view of the fact that the form of metal is suspended directly over the opening in the bottom of the furnace, said bar may be released in any desired manner and be dropped through the opening into the water-bath beneath without coming into by the particular form or forms of metal being treated.

The pressure within the furnace of the gaseous products of combustion is in excess of the atmospheric pressure outside. Consequently all air is driven out of the furnace, and the gaseous products of combustion find no other places of exit except the entrancethroat 7 and the exit-throat 8. As the forms of metal emerge from the exit-throat 8 they pass between the deflector-plates it" at the ends of the throat and the cover-plates 7c which parts practically close the exit-throat, and the excess gaseous products of combustion under pressure pass out between the edges of the cover-plates in the apertures between the forms of metal, and water under pressure is ejected from the pipes 13 and 14, preferably against the surfaces of the coverplates 74 is, and coming into contact with the hot forms of metal is more or less completely converted into steam, the steam and water completely surrounding the emerging forms of metal and keeping the atmosphere away therefrom while the forms of metal are being cooled.

It is usual, especially in treating gold, silver, nickel, and copper in the manufacture of coin, to prepare the bars with a clean, bright, and highly-polished surface prior to their introduction into the furnace. Heating the same by the gas and air flames does not mar this surface, and as they emerge from the furnace the cooling of the same before they come into contact with the atmosphere maintains this condition of surface and prevents discoloration or oxidation, and consequently makes it unnecessary to resurface the bars preparatory to stamping up the same into coin.

I do not herein limit myself to any precise form of apparatus for carrying out the process herein described nor to the use of, deflector-plates and cover plates in connection therewith. I also do not limit myself to the use of water as a cooling medium, as cold currents of air or the cooling influence of refrigeration or an ice-chamber may be effectually employed against or surrounding a chamber of any desired form in which the forms of metal after heating are received and subject to the presence only of the products of combustion, the atmosphere being excluded. I also do not limit myself to any form of cooling-chamber asan adjunct to the heatingchamber, as I may employ any desired or advantageous form of apparatus adapted to re ceive the forms of metal from the heatingchamber and hold the same away from the atmosphere and While cooling before removal therefrom.

My improved process is especially adapted for annealing gold,'silver, nickel, copper, aluminium bronze, and similar metals.

I am aware that efforts have heretofore been made to anneal forms of metal in a polished condition by hot-air products of combustion of ordinary furnaces either alone or in the presence of steam; but I believe these have not been successful, as hot airis a very eflective oxidizing agent, especially in the presence of steam, and I do not claim the use of such materials as part of my process.

I claim as my inventionl. The method herein specified of treating strips, bars or other forms of precious or semiprecious metals and preserving the bright polished surfaces thereof, for annealing and tempering the same, consisting in conveying said forms of metal along within and through a substantially closed chamber from which the atmosphere is excluded andsubjecting the Same in transit to the direct heat of air and gas flames, and thereafter cooling the same in the presence of the heated products of combustion and before said forms of metal are admitted to the presence of the atmosphere,-

they emerge from said heating-chamber and while still in the presence of the heated products of combustion to a cooling bath before admitting them to the presence of the atmosphere, substantially as set forth.

3. The method herein specified of heating strips, bars, or other forms of metal for annealing and tempering the same, consisting in passing said forms of metal into a substantially closed chamber, conveying the same along within and through said chamber and subjecting the same while in transit to the direct heat of gas and air flames, passing the same out of said chamber and between devices which substantially close the said throat of said chamber and while still under the influence of the heated products of combustion of said chamber, directing upon said forms of metal fine streams of. water for cooling the same before they are admitted to the presence of the atmosphere, substantially as set forth.

rect heat and action of gas and air flames, passing the heated forms of metal out of said chamber and through an aperture between the juxtaposed edges of devices which substantially'close the throat of said chamber and while still under the influence of the heated products of combustion of said chamber, delivering fine streams of water from opposite directions against and surrounding said forms of metal for cooling the same before they are admitted to the presence of the atmosphere, substantially as specified.

5. The method herein specified of treating strips, bars or other forms of metal for annealing and tempering the same, consisting in conveying said forms of metal along within and through a substantially closed chamber from which the atmosphere is excluded and subjecting the same in transit to the direct heat of air and gas flames, and thereafter cooling the same in the presence of the heated products of combustion and before said forms of metal are admitted to the presence of the atmosphere, substantially as set forth.

6. The method herein specified of heating strips, bars or other forms of metal for annealing and tempering the same, consisting in conveying said forms of metal along, within and through a substantially closed chamber from which the atmosphere is excluded, and subjecting the same in transit to the direct heat of gas and air flames, subjecting said forms of metal as they emerge from said heatingchamber and while still in the presence of the heated products of combustion to a cooling bath before admitting them to the presence of the atmosphere, substantially as set forth.

7. The method herein specified of heating strips, bars or other forms of metal for annealing and tempering the same, consistingin conveying said forms of metal along progressively and substantially continuously within and through a substantially closed chamber from which the atmosphere is excluded, and subjecting the same in transit to the direct heat of gas and air flames, subjecting said forms of metal as they emerge from said heating-chamber and while still in the presence of the heated products of combustion to a cooling bath before admitting them to the presence of the atmosphere, substantially as set forth.

8. The method herein specified of treating strips, bars, or other forms of metal for an- IIO L-uai nealing and tempering the same, consisting in said forms of metal are admitted to the pres- IO conveying said forms of metal along progressence of the atmosphere by directing upon ively and substantially continuously Within said forms of metal fine streams of Water.

and through. a substantially closed chamber Signed by me this 29th day of July, 1902.

from which the atmosphere is excluded, and y subjecting the same in transit to the direct EDWVARD REKHHELM' heat produced by air and gas flames, and there- Witnesses:

after cooling the same in the presence of the GEO. T. PINOKNEY,

heated products of combustion and before BERTHA M. ALLEN.

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