GB1565946A

GB1565946A - Apparatus and method for the heat treatment of filamentarytary metallic material

Info

Publication number: GB1565946A
Application number: GB5527/78A
Authority: GB
Original assignee: NIEHOFF W
Current assignee: NIEHOFF W
Priority date: 1977-04-25
Filing date: 1978-02-10
Publication date: 1980-04-23
Also published as: DE2718318B1; BE866237A; DE2718318C2; IT7822533A0; IT1094508B; BR7802511A

Description

(54) APPARATUS AND METHOD FOR THE HEAT TREATMENT OF FILAMENTARY METALLIC MATERIAL (71) 1, WALTER NIEHOFF, a German citizen, trading as MASCHINEN FABRIK NIEHOFF KG, of 854 Schwabach Fiirtherstrasse 16, Germany, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to an apparatus and method for the heat treatment of filamentary metallic material.

It has been shown that, when filamentary metallic material such as tin-plated wires, for example, pass singly or severally in parallel through a heating stage, they strike against one another or strike together in passage and can finally become soldered together or damaged. Such an event can also happen in the case of wires which are provided with a covering which becomes softened by heat. The subsequent separation of the wires which are soldered or stuck together requires a relatively high work expenditure and frequently results in damage to the covering, so that, in most cases, the end product has to be scraped The latter also applies in the case of a single wire striking laterally against a machine wall or such like. Thus, the article to be heated should pass completely freely through the heating stage, i.e. it should not come into contact in the heating stage with any mechanical support means or with sections of the wall of the machine.

Reference will firstly be made to Figures I and 2 of the drawings, in which: Figure 1 is a schematic view of a wire annealing device with pre-heating, main heating and after-heating stages, according to British Patent Specification No. 1122228, and Figure 2 shows the corresponding side view of this.

Figures I and 2 schematically illustrate the principle of heating the strand-form or filamentary material. In the following description, the filamentary material to be heated is designated by the general term "wire". A wire D to be heated arriving in the direction of the arrow I firstly reaches a roller 2. From here, the wire passes through a pre-heating stage V and arrives at a contact roller 3, which is connected electrically to a positive pole PP of a direct or an alternating current source 4 or 5, respectively. In the latter case, the designation PP-and also the designation MP-negative pole-may be considered as an instantaneous value of the alternating current. An additional contact roller, which is connected electrically to the negative pole MP, is designated by reference numeral 6.

A main annealing or main heating stage H is located between the contact roller 3 and 6 and an after heating stage N between the contact roller 6 and the roller 2. The task of the roller 2 is automatically to close electrically the wire loop guided around the contact rollers 3 and 6. The wire D leaves the heating device in the direction of the arrow 7.

According to one aspect of the present invention, there is provided an apparatus for the heat treatment of filamentary metallic material, where moving filamentary material is heated by electric current flowing through a free length thereof and an electromagnetic field is produced by this heating current, the apparatus comprising means to supply electric current through said free length of filamentary material to heat it as it moves and a reverse current conductor system through which said free length of filamentary material can be passed, said reverse-current conductor system comprising at least one reversecurrent conductor and being arranged, in use. to carry an electric current simultaneously with, and in the reverse direction to, the current passing through said free length of filamentary material and being intended, in use, to carry electric current of such magnitude that an electromagnetic field is produced, which causes said free length of filamentarv material to experience substantially no deflection as it passes through said reverse-current conductor system.

According to another aspect of the present invention, there is provided a method of heat treating filamentary metallic material as it moves, comprising passing an electric current through a free length of the filamentary material to heat it, whilst passing this free length through a reverse-current conductor system, which comprises at least one reverse-current conductor and which carries an electric current simultaneously with, and in the reverse direction to, the current passing through said free length of filamentary material, the current passing through said reverse-current conductor system being of such magnitude that the electromagnetic field produced thereby counteracts the electromagnetic field produced by the current passing through said free length of filamentary material, whereby said free length of filamentary material experiences substantially no deflection as it passes through said reversecurrent conductor system.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to Figures 3 to 7 of the accompanying drawings, in which: Figure 3 is a schematic view of one form of the present apparatus for heat treating filamentary metallic material and shows this apparatus, by way of example, as a main heating stage (see Figures 1 and 2), Figures 3a to 3c illustrate various circuit possibilities for producing a current in the reverse or opposite direction to the direction of the heating current, whereby direct and/or alternating current sources are used if necessary as the single current source for both the heating current and the reverse-direction current, or an external current source for the reverse-direction current is used separate from the source supplying the heating current, Figure 4 is a diagrammatic plan view of an arrangement for allowing positional adjustment of one of the members illustrated in Figure 3, Figure 5 shows a side view of the arrangement shown in Figure 4, Figure 6 is a diagrammatic view of a further form of the present apparatus, and Figure 7 is a view similar to Figure 6 of yet another form of the present apparatus.

In this specification, by reference to a "reverse-current conductor" is meant a conductor which is intended, in use of the present apparatus, to carry an electric current in a direction opposite to the electric current flowing through the filamentary material being heated, and in which the reverse-current conductor and the filamentary material are adiacent one another.

Figure 3 schematically represents the present apparatus: for improved clarity, the apparatus is shown here only at the main heating stage H; analogously, however, either the pre-heating stage V or the after heating stage N or both can be equipped with the apparatus either together with or instead of the present apparatus for the main heating stage H.

The wire takes fhe same course as described with reference to Figures 1 and 2, i.e. the heating current in the main heating stage H passes to the negative pole MP from the contact of the positive pole PP via the contact roller 3 through the wire D to the contact roller 6 in the direction of the arrow 0.

An electrical conductor system 9, which may be rigidly constructed in the form of a ladder, for example, is arranged between the two contact rollers 3 and 6, i.e. within the heating stage. The "side-pieces" of the ladder-type system thereby serve as current supply and discharge lines 10 and I 1 and the "rungs" serve as reverse-current conductors 12, which run across from one "side-piece" to the other and, if necessary, also over and/or under the heated wires D, the wires D being able to be passed between and parallel to the respective rungs.

The positive pole PP of the current source is connected to the current supply line 11, so that the course of the current in the conductor system 9 from the current supply line 11 is via the individual parallel running current conductors 12 to the current supply line or discharge line 10, i.e. in the direction of the arrow 13. The magnitude of this current can be controlled by an electrical resistance Rx connected in parallel to the conductor system 9. The resistance Rx can also be automatically adjusted by motor operation as a function of the magnitude of the respective heating current in the wire.

As the heating currents in the wires D pass according to the arrows 8 in the opposite direction to the currents in the conductor system 9 indicated by the arrows 13, their respective electromagnetic fields- with adjustment-are completely or almost completely cancelled so that the effect of the electromagnetic attraction does not have a disturbing effect on the wires D. In this way, the wires D are intended to pass through the heating stage completely freely without any contact with other parts, so that it is not possible for neighbouring wires to solder or adhere together.

In order to achleve a proportionality of the heating current through the wire D and the reverse current flow through the conductors 12, the electric current for the reverse current supple many also sere at the same as a current supply line to heat the wire D. In this case, it is necessarv only for the conductor line 10 to be connected electrically with the current supply line contact PP of the contact roller 3, as indicated by the current connection line 14 shown in dotted lines in Figure 3.

Figures 3a to 3c represent in each case the heating of a single wire D. It will be appreciated, however, that the apparatus depicted can be designed to cater for several wires.

Figure 3a shows the circuit tor the wire heating current and the reverse-current for the conductor system 9 from a single alternating current source MW, which may of course instead be a direct current source.

Both the wire heating circuit and the conductor system 9 are connected in series for producing the counter electromagnetic field. The two reverse-current conductors 12 are connected in parallel. The course of the wire heating current flow is indicated by the arrow 8 and the course of the reversecurrent flow by the arrow 13.

The arrangement in Figure 3b differs from that shown in Figure 3a only in that a separate current source is provided for each of the two systems, namely for the wire heating circuit and for the reverse-current conductor system 9. The wire heating circuit is supplied by an alternating current source MW1, while an alternating current source MW2 is connected to the conductor system 9. In this case also, one or both alternating current sources may be replaced by one or two direct current sources, respectively.

As a variation from the arrangements shown in Figures 3a and 3b, two electricallyisolated reverse-current conductors 12 and 12' are provided in Figure 3c, whereby the reverse current conductor 12 and the heating stage for the wire D are connected in series and both are supplied by an alternating current source MW. The reverse-current conductor 12' is connected directly to a separate direct current source MG. The two current sources used may also be interchanged if required.

Normally, a current with 50 Hz is used as the alternating current source. However, the frequency of the heating and/or the frequency of the reverse current can be selected from the medium or high frequency range, in which case the frequency in the medium frequency range should be regarded as up to 15 KHz and the high frequency range as above this. It is also possible to modulate the low frequency current of 50 Hz with a current of another frequency.

Figures 4 and 5 shows a possible arrangement of a reverse-current conductor 17 I) designates the wire to be heated.

which ls supplied with current between the contact rollers 3 and 6. The reverse-current conductor 12 consists in its simplest form of a wire or plate part which is connected with a holder 15. Clearances are made in the holder, which clearances take the form of oblong openings 16 or are of curved shape as indicated by 17. By means of these openings 16, 17, it is possible to be able both exactly to align the reverse-current conductors 12 between the two contact rollers 3 and 6 and to attach them transversely nearer to or more distant from the connecting line between the two axial centres of the contact rollers. The reversecurrent conductors 12 are covered or coated on the side facing the wires D with an insulating layer 18, so that the wires are at least partially surrounded by insulating material to protect the wires D to avoid a direct electrical contact between the wires and the conductors 12, for example, in the case of a break in the wires.

In order that a same reverse-current conductor holder 15 may also be used for a different number of wires, it is advantageous to provide additional, reverse-current conductors, which are interchangeable with the reverse-current conductors already on the holder.

Figure 6 represents reverse-current conductors 12 of different cross-sectional forms. The reverse-current conductors designated by 12a have a cylindrical crosssection with a longitudinal slot 19 for the insertion of the wires D, while the reverse current conductor designated by 12b is substantially U-shaped or channel-shaped.

The reverse-current conductors 12 may also be of different lengths and/or be provided in their longitudinal directions with cross-sections of varying size, in order thus to obtain varying current densities per unit area and thus varying field ratios. For this purpose, the cross-sectional variations of the reverse-current conductors 12 may be effected continuously or in stages.

In order that the wires D may be heated inside a steam or protective gas atmosphere, it is of advantage for the reverse-current conductor system to be of chamber or boxtype construction and to serve as a steam or protective gas chamber, respectively.

Accordingly, in the example shown in Figure 6, the reverse-current conductors 12a and 12b are coated with insulating material 18 on the side facing the wire D.

Otherwise, the reverse-current conductors 12 are embedded in insulating material 20 and form the upper part 21 of a hinged box whose lower part is designated by 22 and is provided with a sealing plate 23 to provide a gas-tight sealing of the longitudinal slot 19.

In this way, when the box is hinged closed and secured by fastenings, steam or protective gas can be introduced into the cavities, which are only partially filled by the wires D, without any appreciable steam or gas loss thereby occurring.

In Figure 7, the wires D are accommodated in chambers 24 having substantially U-shaped cross-sections, which chambers can also be used as steam or protective gas chambers, that is in the base portion of a box consisting of insulating material. The reverse-current conductors 12 are integrally cast on all sides. If required, a conductor plate 25 acting as a reversecurrent conductor can also be integrally cast. Also, in some cases, it can be advantageous for a current conducting plate 26 to be placed in the hinged lid 27 as a reverse-current conductor and arranged so that this plate may be pushed in and out in a slot 29 according to the double arrow 28. In its operating position, the plate 26 is preferably fixed by screws 30, which are sunken and/or arranged in an insulated manner, and is interchangeable with other plates 26 to suit various operations.

It will be appreciated that, with the present apparatus, several mutually parallel running wires, including, for example, copper wires, can be heated in a relatively closely confined space without these wires being soldered or otherwise joined together upon leaving the heating stage.

WHAT I CLAIM IS: 1. An apparatus for the heat treatment of filamentary metallic material, where moving filamentary material is heated by electric current flowing through a free length thereof and an electromagnetic field is produced by the heating current, the apparatus comprising means to supply electric current through said free length of filamentary material to heat it as it moves and a reverse current conductor system through which said free length of filamentary material can be passed, said reverse-current conductor system comprising at least one- reverse-current conductor and being arranged, in use, to carry an electric current simultaneously with, and in the reverse direction to, the current passing through said free length of filamentary material and being intended, in use, to carry electric current of such magnitude that an electromagnetic field is produced, which causes said free length of filamentary material to experience substantially no deflection as it passes through said reverse-current conductor system.

2. An apparatus as claimed in claim 1, wherein said free length of filamentary material and said reverse-current conductor system are connected electrically in series with one another.

3. An apparatus as claimed in claim I, wherein said free length of filamentarv material and said reverse-current conductor system are connected electrically in parallel with one another.

4. An apparatus as claimed in claim I and being arranged to supply electric current to said free length of filamentary material and to said reverse-current conductor system from respective independent power sources.

5. An apparatus as claimed in any one of the preceding claims, wherein said reversecurrent conductor system includes means to adjust the relative magnitude of the currents flowing, in use, through said free length of filamentary material and said reversecurrent conductor system.

6. An apparatus as claimed in claim 5, wherein said means to adjust the magnitude of the currents comprises an adjustable electrical resistance which is arranged in parallel between positive and negative poles of said reverse-current conductor system.

7. An apparatus as claimed in any one of the preceding claims and further comprising means to adjust the relative positions of said reverse-current conductor system and said free length of filamentary material.

8. An apparatus as claimed in any one of the preceding claims, wherein said reversecurrent conductor system is rigidly constructed in the form of a ladder, the "side-pieces" serving as respective current supply and discharge lines and the "rungs" serving as reverse-current conductors, the apparatus being such that a plurality of said free lengths of filamentary material can be passed between and parallel to respective rungs of the reverse current conductor system.

9. An apparatus as claimed in any one of claims 1 to 7 and being so constructed, when two said reverse-current conductors are provided, as to supply these two conductors, which are adjacent, with electric current from a respective independent power source.

10. An apparatus as claimed in any one of claims 1 to 7, wherein said reverse-current conductor system is of a chamber or boxtype construction intended to surround said free length of filamentary material so that the construction can serve as a steam or protective gas chamber.

II. An apparatus as claimed in claim 10, wherein said construction is of two parts to allow introduction of said free length of filamentary material, said two parts being able to be fastened together.

12. An apparatus as claimed in claim 10 or I I and comprising an additional reversecurrent conductor which is adjustable in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. and secured by fastenings, steam or protective gas can be introduced into the cavities, which are only partially filled by the wires D, without any appreciable steam or gas loss thereby occurring. In Figure 7, the wires D are accommodated in chambers 24 having substantially U-shaped cross-sections, which chambers can also be used as steam or protective gas chambers, that is in the base portion of a box consisting of insulating material. The reverse-current conductors 12 are integrally cast on all sides. If required, a conductor plate 25 acting as a reversecurrent conductor can also be integrally cast. Also, in some cases, it can be advantageous for a current conducting plate 26 to be placed in the hinged lid 27 as a reverse-current conductor and arranged so that this plate may be pushed in and out in a slot 29 according to the double arrow 28. In its operating position, the plate 26 is preferably fixed by screws 30, which are sunken and/or arranged in an insulated manner, and is interchangeable with other plates 26 to suit various operations. It will be appreciated that, with the present apparatus, several mutually parallel running wires, including, for example, copper wires, can be heated in a relatively closely confined space without these wires being soldered or otherwise joined together upon leaving the heating stage. WHAT I CLAIM IS:

1. An apparatus for the heat treatment of filamentary metallic material, where moving filamentary material is heated by electric current flowing through a free length thereof and an electromagnetic field is produced by the heating current, the apparatus comprising means to supply electric current through said free length of filamentary material to heat it as it moves and a reverse current conductor system through which said free length of filamentary material can be passed, said reverse-current conductor system comprising at least one- reverse-current conductor and being arranged, in use, to carry an electric current simultaneously with, and in the reverse direction to, the current passing through said free length of filamentary material and being intended, in use, to carry electric current of such magnitude that an electromagnetic field is produced, which causes said free length of filamentary material to experience substantially no deflection as it passes through said reverse-current conductor system.

positional relationship with said at least one reverse current conductor.

13. An apparatus as claimed in claim 12, wherein said additional reverse-current conductor is arranged to be interchangeable with another such conductor.

14. An apparatus as claimed in any one of the preceding claims, wherein the or each reverse-current conductor of the reveresecurrent conductor system has a varying cross-sectional size and/or shape in its longitudinal and/or transverse direction.

15. An apparatus as claimed in any one of the preceding claims, wherein the or each reverse-current conductor of the reverse current conductor system is covered with an insulating material at least on a side thereof that is intended to face said free length of filamentary material.

16. An apparatus as claimed in any one of the preceding claims and comprising two spaced-apart rollers between which said free length of filamentary material is intended to extend, so that said material can be drawn through said reverse-current conductor system, which is disposed between said rollers.

17. An apparatus for the heat treatment of filamentary metallic material, substantially as hereinbefore described with reference to Figure 3, or Figures 4 and 5, or Figure 6, or Figure 7, each with or without the modification of Figure 3a, Figure 3b, or Figure 3c.

18. An apparatus for the heat treatment of filamentary metallic material as claimed in any preceding claim and being incorporated in a pre-heating stage, a main heating stage or an after heating stage of a wire annealing device.

19. A method of heat treating filamentary metallic material as it moves, comprising passing an electric current through a free length of the filamentary material to heat it, whilst passing this free length through a reverse-current conductor system, which comprises at least one reverse-current conductor and which carries an electric current simultaneously with, and in the reverse direction to, the current passing through said free length of filamentary material, the current passing through said reverse-current conductor system being of such magnitude that the electromagnetic field produced thereby counteracts the electromagnetic field produced by the current passing through said free length of filamentary material, whereby said free length of filamentary material experiences substantially no deflection as it passes through said reversecurrent conductor system.

20. A method as claimed in claim 19, wherein the electric current being passed through said free length of filamentary material is direct current or alternating current.

21. A method as claimed in claim 19 or 20, wherein the electric current being carried by said reverse-current conductor system is a direct current or an alternating current, or has a direct current passing through one part of it and an alternating current passing through another part of it.

22. A method of heat treating filamentary metallic material, substantially as hereinbefore described with reference to Figure 3 or Figures 4 and 5, or Figure 6, or Figure 7, each with or without the modification of Figure 3a, Figure 3b or Figure 3c of the accompanying drawings.