US3233884A - Furnace for the treatment of strip metals - Google Patents

Description

FURNACE FOR THE TREATMENT OF STRIP METALS Filed Sept. 6, 1962 5 Sheets-Sheet 1 INVENTOR.

BY BERNARD LAM/E A-r-ro mveys Feb. 8, 1966 B. LAINE FURNACE FOR THE TREATMENT OF STRIP METALS S Sheets-Sheet 2 Filed Sept. 6, 1962 F l llllll INVENTOR. Bax/mm) LA [NE BY WWW 5 m- Feb. 8, 1966 B. LAINE 3,233,884

FURNACE FOR THE TREATMENT OF STRIP METALS Filed Sept. 6, 1962 3 Sheets-Sheet 5 F iq. 3

INVENTOR.

BER VRRD 77(,%-MJ/ 7414a United States Patent 1 Claim. for. 2664) The invention has for its object a furnace for the treatment (annealing and quenching) of strip metals, in particular aluminium or copper alloys.

The furnace according to the invention is constituted by a chamber having a vertically elongated shape, preferably with a narrow rectangular section, the lower end .of which communicates with a tank which contains a cooling liquid for the treated metal, said chamber being provided at its upper end with means for the continuous supply of the strip metal to be treated and at its lower end with means to continuously withdraw the treated strip metal, whereas along the path of the metal in said chamber suitable means are arranged for the heating of said metal.

Owing to this particular relatively simple structure, it is possible to perform a quick treatment of the strip metals and to bestow to the latter particular metallurgical characteristics, namely: a very great fineness of the grain, and elongations which are greater by 20 to 30% than those which are obtained for the same alloy in a conventional furnace. There is obtained in addition a fixation of the metallurgical structure owing to the quick cooling. Moreover, since the strip metal descends vertically along the axis of the chamber, it is not in contact with the feeding or guiding members so that its surface is free from scratches. Besides, with such an arrangement it is possible to provide a furnace having relatively reduced dimensions in relation to those of the usual equip ments.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIG. 1 is a vertical cross section taken along line I-I of FIG. 2;

FIG. 2 is a vertical cross section taken along the broken line IIII of FIG. 1, and

FIG. 3 shows to an enlarged scale a detail of the upper part of FIG. 1.

The furnace for the annealing and quenching treatment of strips of aluminium or copper alloys is essentially constituted by a chamber 1 having a vertically elongated shape and a narrow rectangular section, supported by a framing 2 and the lower end of which communicates with a tank 3 which contains a cooling liquid for the treated metal.

The chamber is surrounded by a casing 6 which is in communication with the inside of chamber 1, on one hand in the vicinity of the lower end thereof through openings 7 and, on the other hand, in the vicinity of the upper end thereof through openings 8.

A blower 17 supplies combustion air, through a piping 16, to a set of gas burners generally denoted by 18 and opening into chamber 1 in the vicinity of the upper end of the latter. Said burners are designed to bring the metal to be treated to the desired temperature for instance of the order of 650 to 750 C.

The hot gases circulate in a closed circuit in the upward direction in chamber 1 and in the downward direction in the casing 6. Said gases are circulated, in the example, by means of a plurality (four in the shown embodiment) of outward-flow turbines, such as 11, each 3,233,834 Patented Feb. 8, 1966 of them being driven from an electric motor 12 through a V-belt transmission 13.

Electrical resistances such as 21 are distributed practically the whole height of chamber 1, underneath the gas burners 18, and are designed to keep the metal at the temperature to which it is raised by said burners 18.

The strip metal to be treated is introduced into the upper end of chamber 1 and it comesout therefrom, in the treated condition, at its lower end. T 0 this end, the upper part of the framing 2 supports a platform 24 on which there is mounted a feeding system including four rolls 25, 26, 27, 28 whose outer cylindrical surface is coated with a layer of rubber. Rolls 25 and 27 are substantially tangent along a generating line which is in the middle vertical plane of chamber 1, whereby the roll 27 may be applied, preferably elastically, against the roll 25. The roll 23 rests on the roll 25 and may be applied also elastically against the latter or through a pressure adjusting screw system. Said four feed rolls are driven from a motor provided with a reducing gear 31, the output shaft of which is connected through a belt or chain transmission 32 with the shaft 33 of the roll 25. The shaft 33 carries a gear 34 engaged with two other gears 35, 36, respectively integral with the two rolls 27, 28. Lastly, the roll 26 is driven from the roll 25 by a chain or belt transmission 37.

The strip of metal 16 to be treated passes first over the roll 26 then between the rolls 25 and 28 and finally between the rolls 25 and 27 of the feeding device. It passes then between two rubber lined centering rolls 38, 39 which are also supported by the platform 24 and hence it descends vertically through the Whole height of chamber 1. At the exit from the lower end of chamber 1, the strip of the treated metal 10 passes under a rubber lined tension roll 41, then between a pair of rubber lined withdrawing rolls 42, 43 and hence leaves the furnace equipment.

The tension roll 41 is vertically movable in two slide ways 45, 46 in which both ends of its shaft 47 may slide. The Weight of roll 41 determines the tension of the metal strip which is already tensioned, in its vertical course inside chamber 1, by its own weight.

The withdrawing rolls 42, 43 are driven through a transmission 49 from a unit including an electric motor and a speed adjusting device generally denoted by 51, the assembly being designed and arranged in such a way that the withdrawing speed of both rolls 42, 43, at the exit of the furnace, are under the control of speed of the upper feed rolls. To this end any suitable conventional equipment is used.

Centering rolls 38, 39 are mounted on the ends of two horizontal push- members 54, 55, respectively, which are connected to the rods of two jacks 56, 57. By actuating the jacks in either direction, it is possible to retract both rolls 38, 39, in particular to make pass between them the end of a metal strip to be treated when beginning to introduce the latter into the furnace or, contrarily, to move them toward each other so that they press between themselves the metal strip which descends into the furnace.

The upper end of chamber 1, which is comprised between the high heating area, which includes the gas burners 18, and the level of the platform 24, is surrounded by a pre-heating chamber 58.

The entry of the metal into said chamber 58 takes place between two rims 61, 62 (FIG. 3) which are constituted by two coolant chambers or water-jackets in which cooling water circulates.

Ducts 63 for the exhaust of the heating gases communicate with pre-heating chamber 58.

At several (two in the example) levels of chamber 1 there are arranged within the latter graphite guide-blocks 65-66, 67-68 designed to prevent the metal sheet from having a tendency to move away from the middle vertical plane of chamber 1. Each of said guide-blocks, such as the guideblock 65, is horizontally adjustable in the direction of that guide-block'whioh faces it, by means of any suitable adjusting system denoted in its entirety by 69.

There has been indicated, at the lower part of the casing 6, shutter 71 whose inclination may be adjusted by means of hand levers 72 which are operable from the outside to regulate the quantity of the air which is recycled in chamber 1.

The working of the furnace is as follows:

The metal strip 10 to be treated is driven by the feed rolls 25 to 28 and is introduced into the upper end of chamber 1, between the centering rolls 38, 39. It is first submitted to a pre-heating in the upper chamber 58 in which it is degreased by the evaporation of the oils; it passes then between the gas burners 18 which raise its temperature to the vicinity of 650 to 700 C. It descends on into chamber 1 between the electrical resistances 21 which maintain it at said temperature. It comes out at the lower end of chamber 1 and passes then into the liquid which is contained in the tank 3 so that, after having been submitted to an annealing in chamber 1, it is quenched in saidliquid. It passes round the roll 41 which maintains it at the desired tension and it emerges from the equipment through the withdrawing rolls 42', 43.

While the metal strip is discending through chamber 1, it is swept by the upwardly flowing convection heating gases which are circulated by the turbines 11.

If, for any reason, it is necessary to momentarily raise the metal strip in the furnace, there are placed in operation pressure air blowing nozzles, which are located on the platform above the centering rolls 38, 39. Thereby, there is no risk of damaging the rubber coatings of the feed rolls.

The apparatus produces strip metals of a very high quality having a very fine grain and without any scratches since the sheets or strips descend vertically without being in contact with driving or guiding members. The graphite guide-blocks are practically not in contactwith the metal strips, in any event, do not exert pressure against it; they merely serve to keep it in the centered condition in the event it should have a tendency to deviate very l slightly from the middle vertical plane of the chamber. The strip thus retains a very beautiful appearance. The furnace has a relatively small height and the treatment is performed very quickly.

While a particular embodiment of this invention has been illustrated and described herein, it is intended that this invention be not limited to such disclosure, and changes and modifications can be made and incorporated within the scope of the claim.

I claim:

An annealing furnace for continuously heating and quenching non-ferrous strip metal, particularly strip of aluminium, copper, and alloys thereof, said furnace comprising in combination, a vertically elongated chamber having an upper end and a lower end; means for feeding the strip metal through said upper end for passage downwardly through said chamber along a substantially central vertical plane therethrough; a tank containing a cooling liquid positioned adjacent and in communication with the lower end of said chamber; means adjacent the lower end of said chamber operable to draw strip metal from said feeding means downwardly through said chamber and through the cooling liquid in said tank for discharge from said furnace; oxy-fuel burners positioned adjacent but below said upper end of said chamber for directing hot combustion gases perpendicularly against opposite surfaces of strip metal passing through said chamber to heat the strip metal to an annealing temperature; and electric heating means disposed along said chamber between the location of said burners and said lower end of said chamber, and in heat transfer relation with the metal strip to maintain said annealing temperature of the metal strip during passage thereof through said chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,890,065 12/1932 Meehan. 2,926,902 3/1960 Roth et al 2663 2,933,425 4/1960 Hess 266-3 X JOHN F. CAMPBELL, Primary Examiner.

MORRIS O. WOLK, JAMES H. TAYMAN, JR.,

Examiners.

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