DE1248308B - Vacuum furnace for the continuous annealing of strips made of reactive metal - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C22d

German class: 40 d - 1/02

Number: 1 248 308

File number: M 65345 VI a / 40 d

Filing date: May 24, 1965

Opened on: August 24, 1967

The invention relates to vacuum furnaces used for the continuous annealing of strip material made of reactive Metals, e.g. B. made of titanium, are used.

Furnaces for annealing strip material generally contain devices for resistance or Gas heating, whereby the entire furnace has to be heated up to operating temperature. With such ovens an expensive refractory furnace lining is required, in addition, because of the considerable Time it takes to heat such ovens sufficiently ίο from room temperature to operating temperature is required, it is necessary to keep such ovens on or close to their operating temperature. Find such furnaces for annealing reactive ones Using metal, it is also necessary to have a sealed vacuum chamber inside the furnace is arranged.

The invention is based on the object of a vacuum furnace for annealing reactive To create metal that is not exposed to high temperatures between each operating period must be kept, in which the heat energy directly from the heat source to the the metal to be treated is transferred without the furnace itself being heated, the heat sources can be operated under vacuum, i.e. a closed vacuum chamber is not required, and the material to be treated directly as economically as possible and is effectively heated.

This object is achieved in that in a vacuum furnace for heat treatment of metal with a vacuum chamber and means for guiding the metal strip to be annealed in and out, according to the invention In the vacuum chamber heating elements which contain at least one infrared lamp are arranged and means are provided for evacuating the vacuum chamber.

In a preferred embodiment of the invention, find infrared quartz lamps and reflectors advantageous use for these lamps.

The features of the invention and further advantages are illustrated with reference to the following drawings the same explained. It shows

F i g. 1 is a side view of a vacuum furnace according to the invention, partially in section,

FIG. 2 is a top view of a vacuum furnace according to FIG. 1, partially in section,

F i g. 3 shows a section along the line 3-3 of FIG. 1,

F i g. 4 shows a section along the line 4-4 of FIG. 3,

Vacuum furnace for the continuous annealing of
Reactive metal band

Applicant:

McGraw-Edison Company, Elgin, JH. (V. St. A.)

Representative:

Dipl.-Ing. H. Stehmann

and Dipl.-Phys. Dr. K. Schweinzer,

Patent attorneys, Nuremberg, Essenweinstr. 4-6

Named as inventor:

Peter J. Wynne, Pittsburgh, Pa. (V. St. A.)

Claimed priority:
V. St. ν. America September 25, 1964
(399 226)

Fig. 5 is a section along the line 5-5 of Fig. 3,

F i g. 6 shows a section along the line 6-6 of FIGS

F i g. 7 shows a section through details of a further exemplary embodiment of one according to the invention Vacuum furnace.

The in the F i g. 1 and 2 illustrated embodiment of a vacuum furnace according to the invention for annealing strip material has a roller stand which is designed so that a vacuum-tight seal is ensured during the continuous entry and exit of the strip from the furnace, as well as a main vacuum chamber 11 and a heated vacuum chamber 12th

The roll stand 10 used in this exemplary embodiment of the vacuum furnace according to the invention is arranged in a long, horizontally arranged metal housing 14 which comprises several groups of cylindrical rolls 15 which bring the strip 17 into and out of the furnace. In the illustrated embodiment, the rollers 15 are arranged in groups of three rollers each, in such a way that the rollers within each group are aligned parallel and perpendicularly one above the other and each extend transversely in the cylindrical housing 14. The roller groups 15 are horizontal within

709 638/460

and arranged along the cylindrical housing 14 at a distance from each other such that the upper and the middle roller 15 in each group move the belt entering the furnace while the middle and lower rollers 15 in each group convey out the belt leaving the oven.

Within the housing 14 there are in each case a number between adjacent groups of rollers 15 arranged transversely therein extending channels 18 with an elliptical cross-section; each of these elliptical Channels 18 have a pair of opposing slots 20 through which the band 17 is passed can be. These channels 18 alternately penetrate the side walls of the housing 14 and 14 are connected to an evacuation device (not shown in the drawings).

The main vacuum chamber 11 is formed by a substantially cylindrical metallic container 22 is formed, which is arranged coaxially with the cylindrical housing 10 surrounding the rollers 15 is and at one end an opening 23 to having a vacuum-tight connection to the open end of the roller housing 14. In one side of this metallic container 22 open two evacuation connections 24, one is in the vicinity one of the two ends of the housing arranged; the evacuation connections 24 are provided with a (in the drawings not shown) evacuation device connected.

The heated vacuum chamber 12 consists of a long, cylindrical metal container 25, which extends from the container 22 forming the main vacuum chamber extends vertically upwards and at his The lower end is provided with an opening 29 for connection to the top of this container 22. The upper end of the vacuum chamber 12 is closed by means of a suitably designed metallic cover 26, which is arranged vacuum-tight at this end, closed.

After the metal strip 17 to be annealed has entered the main vacuum chamber 11, it runs under a guide roller 27, which is arranged directly under the opening 29 of the vacuum chamber 12 is to be deflected by this roller 27 into the vacuum chamber 12. In the vicinity of the At the upper end of the vacuum chamber 12, a second pulley 28 is arranged through which the incoming Metal strip 17 is deflected downward to be guided there by a guide roller 30 for removal to be deflected by the roller housing 10.

The vacuum chamber 12 is divided into three zones:

1. a heating zone,

2. a heating zone,

3. a cooling zone.

The heating zone is arranged at the lower end of the container 25 above the introduction roller 27 and serves to heat the metal strip 17 substantially up to the annealing temperature; in the In the heating zone, the metal temperature reached in the warm-up zone is increased and / or to the desired one Height maintained while in the cooling zone the temperature of the belt 17 before contact with the guide roller 30 is reduced.

The metal belt 17 is supplied with heat by a number of infrared heating elements 32; these Infrared heating elements 32 extend across the vacuum heating chamber 12. As shown in FIG. 3 4 and 4, each of these infrared heating elements 32 consists of a long infrared quartz lamp 33 and a reflector 34. In the illustrated advantageous embodiment of the invention Vacuum furnace, the reflector 34 is made of polished aluminum and has a parabolic Shape, the infrared quartz lamp 33 is arranged in the focal point of the parabola.

ίο The infrared heating elements are in the heating zone 32 arranged close to one another, which is why the belt 17 is quickly heated to the desired temperature can be. In the heating zone, however, the infrared heating elements 32 are at greater distances from one another arranged.

In an advantageous embodiment of the vacuum furnace according to the invention, there is the infrared heating element from a tubular infrared quartz lamp, through its relatively narrow bore a tungsten turn] extends. Infrared quartz lamps are particularly advantageous as heating elements, because they are able to withstand high temperatures; they have a melting point from about 1700 ° C.

In order to utilize the thermal energy released by the heating elements 32 more effectively, is at the illustrated embodiment of the invention a pair of parallel, closely spaced water-cooled reflector plates 36 and 37 between the heating elements and the container wall arranged, from the lower end of the vacuum chamber 12 upwards around the upper pulley 28 around to the start of the cooling zone. In addition, as can be seen from FIG. 3, a Pair of substantially flat, water-cooled side reflector plates 39 at right angles to the Reflector plates 36 and 37 arranged. These heat reflectors 36, 37 and 39 can be of any one be a suitable material, but polished aluminum is particularly advantageous for this.

As can also be seen from FIG. 3, each infrared heating element 32 is attached parallel to the direction of passage of the metal strip. In order to keep each of these heating elements 32 in this position and to enable the lamps 33 to be replaced, the container 25 is provided with a number of openings 43, aligned on a vertical line, for receiving lamp holding elements 44.
As can be clearly seen on a larger scale from FIG. 5, each lamp holder element 44 consists of a cylindrical part 45 which extends through the opening 43 and has an outer flange 46 which is fixedly connected to the edge of the opening 43 in a suitable manner . A circular base plate 48, which has a central bore 50, is attached to the inner end of this cylindrical part 45. A circular holding plate 52 is arranged in the vicinity of the plate 48 and serves to hold the lamp holder element 44 within the vacuum chamber 12. The holding plate 52 is fastened to the base plate 48 by means of screws 53, which are inserted into threaded bores 54 and 55 in the holding plate 52 or the base plate 48 sit. An annular seal 57 is arranged in an annular groove in the holding plate 52 and serves to seal between the holding plate 52 and the base plate 48. The holding plate 52 is also provided with a central opening 58 which is coaxial with the opening

tion 50 is in the base plate 48 and through which a lamp holder 59 of a support element

44 protrudes into the container 25.

In the case of the one shown in FIG. 5 shown advantageous embodiment of the vacuum furnace according to the invention, the lamp holder 59 has a hollow tube section 60, which extends through the opening 58 in the holding plate 52 and at her A flange 63 at the upper end. Another ring seal 62 is in an annular groove around the opening 58 arranged around; this serves to seal the connection between the holding plate 52 and the Lamp holder 59.

The upper, outwardly protruding end of the lamp socket 59 is secured by means of an end cap 64 closed with a flange 65 which is attached to the flange 63. Lamp holder 59 and end cap 64 are firmly connected to the holding plate 52 by means of screws 67. In an annular groove in the flange 65 an annular seal 68 is arranged; this seals between flange 65 and flange 63. aside from that the end cap 64 has a tubular connection set 70, one end of which extends in the axial direction through the end cap 64 extending through electrical connection 72 surrounds.

The end of the lamp 33 is within the tube section 60 of the lamp socket 59 also means of a spacer 74, as shown in FIG. 6 can be seen. This spacer 74 consists of a ring clip 75 which includes the lamp 33, from which a number of arms 76 extend radially outward; the arms 76 are frictionally supported against the inner surface of the pipe section 60 from.

The free end of the lamp connector 78 is clamped to the inner end of the connector 72, the is connected to the mains.

Lamp socket 59 and end cap 64 are made of electrically insulating material so that the connection 72 is electrically properly insulated from the metallic container 25.

One end of the reflector 34 is provided on the inner surface of the by means of a number of long L-shaped ridges Base plate 48 attached.

In the case of the one shown in FIG. 5 shown embodiment is a lamp 33 directly inside the vacuum chamber 12 freely arranged.

In another advantageous embodiment of the invention, which is shown in Fig. 7, is a lamp 33 enclosed by a long quartz tube 80. The quartz tube 80 replaces the lamp socket 59; it extends into the cylindrical part

45 inside. The in F i g. 7 shown embodiment is particularly advantageous in such systems, in which the high operating voltages do not allow lamp connections within the chamber 12 expose to vacuum; the arrangement according to the invention prevents the occurrence of here Corona discharges. In addition, if the lamps 33 are to work at a lower temperature, In this embodiment it is possible to supply the ends of the quartz tube 80 with a cooling gas Connect facility.

As shown in FIGS. 1 and 3 can be seen, the cooling zone consists of a pair of hollow, parallel arranged water-cooled copper plates 84, which are on both sides of the metal strip 17 and above the Guide roller 30 are attached at a small distance from the belt. 86 is a cooling water connection for the plates 84. In addition, near the inner of the two cooling plates 84 there is a long rectangular one Arranged reflector 87, which reflects the radiation originating from the heating elements 32. Since the arrangement and design of the heating elements 32 according to the invention is a perfect one If working in a vacuum is permitted, this can be arranged directly within the vacuum chamber be. Therefore, there is no special vacuum chamber as in known ovens with gas heating elements necessary.

In addition, the heat is supplied directly by radiation, so that practically negligible little or no heat at all heats the furnace walls. Although the tape is set to temperatures of approximately 800 ° C is heated, which is necessary to z. B. to anneal titanium is not for the vacuum chamber 12 expensive refractory furnace lining necessary, as is the case with known annealing furnaces.

It is also not necessary to bring the furnace to the operating temperature itself, as is the case with known ones Ovens is necessary; the radiation source can therefore be switched off between the operating periods and only needs to be switched on again a short time before starting work.

Claims (8)

Patent claims: 1. Vacuum furnace for the continuous annealing of strip of reactive metal, e.g. B. off Titan, consisting of a vacuum chamber and means for inserting and removing the glowing metal strip, characterized in that heating elements in the vacuum chamber are arranged, each consisting of at least one infrared lamp and which are attached parallel to the direction of travel of the tape, as well as that a device for evacuation the vacuum chamber is provided. 2. Vacuum furnace according to claim 1, characterized in that long infrared quartz lamps are used as infrared lamps Find use. 3. Vacuum furnace according to claim 1 or 2, characterized in that means for reflection the infrared rays emanating from the lamps are provided on the metal. 4. Vacuum furnace according to one of claims 1 to 3, characterized in that the vacuum chamber consists of a metallic container that this container has a number of openings for receiving the infrared lamps and means for removable near each of these openings Has holding these lamps, and that further means connected to the holding means are provided to seal the openings. 5. Vacuum furnace according to one or more of claims 1 to 4, characterized in that within the vacuum chamber the infrared lamps along a substantial part of the path of the metal strip and cooling elements are arranged, which extend along the remaining part extend the path of the metal band within the vacuum chamber. 6. Vacuum furnace according to one or more of claims 1 to 5, characterized in that in the vacuum chamber in the area of the belt If the infrared lamps step closely next to each other and plate-shaped cooling elements in the area of the Band entrance are arranged, while dazwi · * see the infrared lamps at greater distances are arranged from each other. 7. Vacuum furnace according to one or more of claims 1 to 6, characterized in that The heating elements have parabolic reflectors on each of the infrared lamps are assigned, and that each of these infrared lamps in the focus of its associated reflector is held. 8. Vacuum furnace according to one or more of claims 1 to 7, characterized in that between the heating elements and the chamber wall and between the heating elements and the Cooling elements plate-shaped reflectors are arranged. 1 sheet of drawings