US2352709A - Apparatus for annealing articles - Google Patents

Description

July 4, 1944. c. o. HAASE APPARATUS FOR ANNEALING ARTICLES Filed Nov. 26, 1942 //vl/A/TOR c. 0. f/AASE I By I ATTORA/fy Patented July 4, 1944 UNITED STATES new APPARATUS roa ANNEALING ARTICLES.

Carl 0. Haase, Baltimore, Md., assignor to Westcrn Electric Company, Incorporated, New York, N. Y., a corporation of New York Application November 26, 1942, Serial No. 467,065

7 Claims.

This invention relates to apparatus for annealing articles, and more particularly to a regenerative water heating system for annealing furnaces.

Water seals are frequently used for preventing the entrance of air into annealing furnaces, since such seals are cheap andeifective. Due to the difference in temperature of the tap water generally employed in water'seals and the annealing gas in the heatingc'hamber of the furnace, aconsiderable amount of heat is absorbed by the water in the water seal When the heated water from the seal is withdrawn through an overflow pipe, the heat absorbed by the water is lost.

An object of this invention is to provide apparatus for annealing articles and more particularly to provide a regenerative water heating system for annealing furnaces.

In general, the invention comprises an annealing furnace having a water seal for sealing the furnace from the atmosphere, and means for spraying water from the Water seal upon hot articles in the furnace to cool them, said means being so located that the water flows from th hot articles into the water seal.

Other features and advantages of the invention will become apparent from the following detailed description thereof, when read in conjunction with the accompanying drawing in which the single figure represents a schematic sectional view of an annealing furnace.

In the particular embodiment of the invention disclosed in the accompanying drawing, an annealing furnace is provided with a housing III which encloses a chamber II divided by a bafile I2 into a heating area I4and a'cooling area I5.

, An endless conveyor I! located within the housing I comprises a motor driven sprocket I6 which is rotated at a constant spee'dand which, in turn, drives a chain I8 and a wheel I9. The wheel I9 acts merely as a tensioning wheel for the chain I8 and is located in a pit 20 which is normally-filled with water, thus providing a water seal to preventthe entrance of air into the chamber II A plurality of spool carriers 2I--2I are equally spaced upon the chain l8 for carrying through thechamber II coils of oxidizable metal wire weighing as much as 600 pounds wound on spools 2222. A drum 23 formed on the sprocket I6 holds the spools 2222 in position on the spool carriers 2I-2I while they are passing over the sprocket I6.

- A charging trench 24 provided with a cover'25 is formed in one side of the pit 20 and is filled with water from the pit 2II. The spools 2222 are fed down the charging trench 24 into the pit 20 and upon the conveyor H :by means of an' intermittently moving conveyor 26 which comprises a pair of sprockets 21 and 28 connected by a chain 29. A number of cross bars 3II30 are spaced along the chain 23 so as to permit spools 2222 to be positioned therebetween. When a spool ,22v is fed from the conveyor 26 into the pit and onto the conveyor I1, stops 3|, 32 and 33 position the spools 2222 so that they are 1 enaged by the spool carriers 2I2 I.

The spools 2222 are moved upwardly through the heating area I4 in which electrical heating means 31 are located. The particular type of heating means employed does not constitute part of this invention, but one type of heating means that has proved satisfactory comprises a plurality of heating coils arranged in a grid-like formation and disposed so as to form three heating areas. In the cooling area I5 opposite the heating area I4 are positioned a plurality of spray nozzles 347-34 which are supplied with water pumped from the body of'water forming the seal in the pit 20 by a Dump 3-5. The pump 35 is an impeller type pump having an inlet pipe 36 extending below the surface of the water in the pit 20, and pumps the water up through a pipe 38 to branchpipes 3939 which feed the nozzles 34-34. A- trip 40 is so disposd relative to the path of movement of the spools 22 through, the heating chamber II that it rolls the spools from the spool carriers 2I2l through an opening 43 in the housing III onto a discharge apron 4| and into a discharge drum 42. A rotating discharge valve 44 positioned within the drum 42 has two recesses 45-45 formed therein for receiving the spools 2222. A pocket 46 is formed in each recess 45 for the purpose of carrying a spool deposited therein to a rack 48. The recesses 45-45 in the rotating member 44 are so formed that the opening 43 is always closed and the heating chamber I I thus is sealed from the atmosphere.

In operating a furnace such as that shown in the accompanying drawing, spools 2222 carry- 4; ing coils of wire made of an oxidizable metal, such as copper, are introduced into the charging trench 24, and are inserted in the conveyor 26 one at a time. The water in the water seal-is initially heated by passing steam intoit, so that 50 asv the conveyor 26 moves the spools 2222 slowly down the charging trench 24, the coils of wire carried 'by the spools become heated through to about the temperature ofthe water in the water seal, which is about F. to about 200 F., and the occluded gases in the wire coils expand due "and are forced from the coils by The intermittent movement of the to the water.

' conveyor 26 is timed so that a spool from the the heating means is located at a rate of movement such that the wire carried by the spools 22-22 becomes thoroughly heated to the proper temperature by the time it reaches the sprocket I6. Since the wire coils on the spools are preheated nearly to the boiling point of water before entering the heating area l4, the spools may be moved up past the heating means much faster than if the wire were not preheated and were wetted by relatively cold 'water having a temperature of about 40 F. to about 70 F. The drum '23 formed ,on the sprocket it supports the heated spools 22-22 as they pass over the top thereof into the cooling area IS. The conveyor I1 moves the spools carrying the coiled wire downwardly through the cooling area I5 advancing the spools 22-22 past the cooling nozzles 34-34 located therein which are supplied with heated water from the pit 23 by the pump through the pipes 36, .33 and 33-33. When the water from the nozzles 34-34 is sprayed upon the hot coils of wire carried on the spools 22-22,

The generation of steam in this manner has two beneficial effects: First, the steam provides a non-oxidizing atmosphere within the chamber II which prevents oxidation of the wire that is being treated. Second, it permits the maintenance of a slight steam pressure within the chamber ll whichis desirable since it prevents any air from entering therein. The heat absorbed by the water in the water seal is utilized to preheat the wire on the spools as they are advanced down the charging trench 24, and is further useful in promoting rapid evaporation of the water ejected from the nozzles 34-34. Since ordinarily tap water has a temperature of approximately 40 F. to F., when it is sprayed onto the hot coils of wire it is so cool that it cools the coils of wire or portions thereof belowthe boiling point of water and thus permits the cold water to flow into the convolutions of the coils, so that the coils of wire are wet when elected from the furnace. Conversely, when the heated' water from the water seal is sprayed onto the hot coils of wire, this water is so near its boiling point that it cannot cool the coils of wire below this temperature and, consequently, no water can remain upon the wire which is ejected, cooled and dried from the furnace.

The water that flows from. the spools 22-22, the water that does not strike the spools 22-22, and the water that is formed by the condensation of steam on the side walls*of the chamber II is collected in the pit 20. Enough heat is absorbed by the water that runs off after striking the hot spools 22-22 to maintain the temperature of the water in the pit 20 betweenabout 190 F. and

about 200 F., so that after the furnace has been longer be heated by steam introduced therein. In order 'to prevent the water in the pit 20 from rising above 200 F., which would cause excessive generation of steam, it is advisable to provide a small flow 05 cold water into the pit 23, which also maintains the water level constant and compensates for water lost due to evaporation.

The spools 22-22 pass downwardly past the nozzles 34-34 until they strike-the'trip 40 which is positioned so as to roll the spools 22-22 one at a time from the spool carriers 2l-2l .onto the apron 4| and through the opening-43 into the from the time a spool enters the charging trench 24 until it is ejected from the drum 42 is greatly reduced by the use of the regenerative water heating system disclosed in the accompanying drawing. There are several reasons why this remarkable reduction in the time required for the annealing operation is thus effected. In the first place, wire passed through a water seal containing cold water is cold when introduced into the heating area and both the cold wire, weigh-' inr, up to 600 pounds, and the cold water clinging thereto must be gradually heated. The hot water in the water seal, forming part of the above described regenerative water heating system, preheats the wire coiied'upon the spools 22-22 to about 200 F., and when the preheated coils of wire are carried by the conveyor l1 into the heating area l4, the hot water still clinging to the wire is quickly heated to the boiling point and evaporated, thus leaving the wire completely dry. Since the wire coils are preheated to about 200 F. before they enter the heating area l4, and

because the hot water that remains on'the wire.

is already at a temperature near its boiling point, considerably less time is required to heat the wire to the proper temperaturefor annealing than is the'case where the water in the water seal is cold and 400 to 600 pounds of wire and the water clinging thereto must be heated beginning at a temperature as low as 40 F.

Furthermore, when cold water is employed in the water seal and is constantly siphoned of! in large quantities, the heata'bsorbed by the water is continually being drained from the furnace. The heat thus lost is considerabl because the water absorbs a large amount of heat due to the high temperature of the annealing atmosphere within .the heating area l4 maintained by the electric time, and very little, if any, steam from an outside source is required.

What is claimed is:

1. In an annealing furnace, a regenerative water heating system comprising a water seal,

means for spraying water onto articles heated ing'the bottom of the heating chamber in the furnace to prevent entrance of air into the chamber, a plurality of spaced nozzles for directing sprays of water onto hot articles to cool them, the excess water flowing from the articles down into the water seal, and means for supplying the spraying means with water. from the water seal. 3, In an annealing furnace having an endless conveyor for carrying articles to be annealed, a water seal for preventing the entrance of air into the furnace, means for heating the water in the seal, and means for spraying heated water from the water seal upon the articles carried by the conveyor, said water seal being so located as to collect therein all of the water within the furnace.

plying water from the water seal to the spraying means, the water flowing from the spools to the water seal.

6. In an annealing furnace including a chamber, a water seal at the bottom of the chamber for preventing the entrance of air into the cham- 4. In an annealing furnace including a heat ing chamber, an endless-conveyor within the heating chamber; means for feeding articles to be annealed to the conveyor, and means for heating the articles carriedfby the endless conveyor, a water seal for preventing air from entering the furnace, means for spraying water that all the water flowing downwardly in the chamber collects in the seal and supplies heat to the water in the seal.

7,- In an annealing furnace, a chamber comprising a heating zone and a cooling zone, a water seal at the bottom of the chamber in communication with both the heating and cooling zones,

5. In an annealing furnace having a constantly driven endless conveyor for carrying spools wound with wire made of oxidizable metal in a path through the furnace, a second endless conveyor intermittently operated having-its movement synchronized with that of .the constantly driven conveyor to. permit the feeding of the spools from the intermittently operated conveyor to the constantly moving conveyor, electrical means for heating the spools disposed about a means for maintaining the water in the seal at,a predetermined elevated temperature, means for introducing articles to be annealedinto the water seal to preheat them, means for conveying the preheated articles from the water seal through the heating and cooling zones, means in the cooling zone for spraying water upon the heated articles carried therethrough, and means for supplying water from the water seal to the spraying means, the water seal being so positioned that water flowing downwardly in the chamber collects in the seal and supplies heat to the water in the seal.

CARL O. HAASE.

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