US1818341A - Device for annealing metal rings - Google Patents

Description

Aug. 11, 1931. F. LlNNHOFF 1,313,341

DEVICE FOR ANNEALING METAL RINGS Filed Nov. 18, 1929 4 -Fig.] 0J0 If Fig.2

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Patented Aug. 11, 1931 UNITED 'STATES' PATENT OFFICE- IRANZ LINNHOFF, F EBEBSWALDE, GERMANY, ASSIGZNOR TO THE FIRM: HIRSCH, I 'KUPFER- AND MESSINGWERKE AKT.-GES., OF EINOW/ MARK,

DEVICE FOR ANNEALING METAL KIN GS Application filed November 18, 1929, Serial No.

My invention relates to the annealing of metal rings, more particularly to the annealin of metal rings of magnetizable material.

etal bands have been annealed up to today by winding them into rings and heating them 1n an annealing furnace by resistance or inductive heating. The resistance heating has the disadvantage the heat can hardly penetrate through the outer layers of the rings to the inner layers because there are heat-insu lating air spaces between the metal layers. Therefore this annealing method requires comparatively much heating energy. Besides, owing to the slow annealing of the inner layers, the metal does not attain the desired uniform fine grained texture.

The inductive heating is more eflicient but the known inductive heating devices are also disfavourable in. some way because with the known devices the greatest part of the magnetic flux is flowing through air so that a strong stray field arises which causes energy losses as well as a bad power factor.

The object of my invention is to provide a device for annealing metal rings or rings of metal bands which makes it possible to anneal the metal very quickly without considerable energy losses and which works with a good power factor. c

I have illustrated my invention in the accompanying drawings in which Fig. 1 is a cross-section Fig. 2 is a top plan view of an annealing device; and

Fig. 3 is a cross section of a furnace for bright-annealin metals.

Referring to igs. 1 and 2, the annealing material consisting of a ring 1 of metal bands is introduced into the lower art 2" of a subdivided annular induction 0011. This part annular bar 5. The upper and lower parts of the coil are connected by 'springy contacts which are provided 'on the outer limbs of the 408,099, and in Germany November 24, 1928.

lower conductor 2. When the upper part 4 is applied to the lower part of the coil, the springy contacts clasp the outer ends of the radial conductors 4: and thus close the circuit. 1

.As the current supply is connected by the conductors 6 and 10 to the annular bars 3 and 5, the conductors form a continuous winding running round the ring 1 which acts as the iron core of a Gramine ring armature m and is heated by the hysteresis energy as v well as by the eddy currents very quickly and uniformly. Smce with this arrangement the whole magnetic flux is flowing in iron, the stray-losses are minimal. e In Fig. 3, the'lower part of the coil is 10- cated within a 0t 7 of refractory material which after having brought in the annealing material and having completed the'coil can be closed by the oil-sealed cover 8 hermetically. The pot is provided'with tubes 9 and 109 for supplying an inert gas into it in order to prevent the oxidation of the annealing material during the annealing process.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed, what I claim is: 1. In a device for annealing metal rings an induction coil forming the winding of a ring armature the core- .of which being formed by the annealing material. a 2.v In a device for-annealing rings of mag-- netizable material, an induction coil forming the winding of a ring armature the core 35 of which being formed by the annealing material. V 3. In a device for annealing metal rings, an induction coil forming the winding of a ring armature the core of which is formed by the annealing material, the windingsof the coil being subdivided so as to be adaptedto receive the annealing material. 4. In a. device for annealing rings of magnetizable metal, a substantially annular in-. duction coil, each. winding of which consist ing of two parts and means for connecting said two parts one to another.

5. In a device for annealing rings of magnetizable metal, a substantially annular induction coil, each winding of which consisting of two parts, and means for connecting said two parts, the upper part of the windings being adapted to be removed.

5 6. In a device for annealing rings of magnetizable metal, a substantially annular induction coil each winding of which consisting of two parts, the lower part comprising U-shapedi conductors the inner limbs of which being connected by an annular conducting bar, and the upper part comprising radially extending conductors the inner ends of which being connected to one another by an annular conducting bar and the outer ends being adapted to be connected to the outer limbs of said U-shaped conductors.

7. In a device for annealing rings of magnetizable metal, a substantially annular induction coil each winding of which consisting of two parts, the lower part comprising U-shaped conductors the inner limbs of which being connected to one another by an annular conducting bar, and the upper part comprising radially extending conductors 5 the inner ends of which being connected to one another by an annular conducting bar, the outer ends of said radially extending conductors and the upper ends of the outer limbs of said U-shaped conductors forming;

the plug and receptacle of a plug connection;

8. In a device for bright-annealing rings of magnetizable metal, an induction coil forming the winding of a ring armature the core of which being formed by the annealing material and a pot adapted to be sealed hermetically, said coil being located within said pot, and means for maintaining an atmosphere of inert gases within said pot.

In testimony whereof I afiix my signature.

FRANZ LIN NHOFF.

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