DE2945958A1 - Starting electrode assembly for steel surface flame treatment appts. - has ignition and return electrodes movable with main flame jet - Google Patents

Abstract

The electrode arrangement is intended for use on surface flame treatment equipment for large areas, for example steel blooms or billets. The ignition electrode (20), of negative potential, is typically of carbon, and is positioned close to the main flame jet (18). Its function is to preheat and melt an area of the workpiece (16) near the main jet. The return electrode (30) makes contact with the workpiece to close the current path (32) between power source (22) and start electrode. The return electrode is mounted close to the ignition electrode, either as part of the carrier for the latter and the main jet, or on a separate auxiliary gantry travelling along the workpiece close to the gantry supporting the main jet. By this means cable runs are kept short leading to lower power consumption, and electrical contacts between the workpiece and a fixed return path are eliminated.

Description

Password: positive pole

Scarfing Starting Device The present invention relates to a scarfing starting device according to the preamble of the main claim.

The weld pool on the surface of the workpiece to be flamed can be obtained in different ways. So is it is known, for example, to melt the surface in the area of the scarfing start point the temperature by means of the preheating flames of the scarfing burner. To speed up this heating process, it is also known to add iron powder to the preheating flames burn or melt iron wire in these flames. This does one fast scarfing start in contrast to the usual heating without these additional ones Aids.

US Pat. No. 2,513,425 also belongs to the state of the art, from which a scarfing device according to the preamble of the flaupt claim as is known. This scarfing starter has one on the scarfing burner arranged Staltelectrode, which is electrically connected to a power source. At the start of scarfing, the electrode is brought into contact with the workpiece, so that the electrode-workpiece-power source-electrode circuit is closed. When the electrode is lifted, an electrical signal forms between it and the workpiece Arc through which the workpiece surface at the desired scarfing start point melted and immediately afterwards with a flying start, i.e. with the actual one Scarfing by switching on the scarfing oxygen is started.

The problem with this electrical scarfing starter is the Creation of the necessary second pole in addition to the start electrode (= first pole) Area of the workpiece to be flamed. This can be done, for example, by connecting of the individual workpiece supports and their connection to the Scarfing machine existing power source (transformer) either via a hose suspension or by a conductor line, which runs parallel to the track of the (movable) Scarfing machine is arranged, see also Fig. 1 of the drawing.

This type of polarity is very complex and expensive, in particular if you consider that the scarfing machine often stretches long distances during the scarfing process (e.g.

100 meters and more) and it is necessary to cover all of them Workpiece support with each other and with the scarfing machine electrically for formation to connect the circuit for the scarfing start with each other.

The object of the present invention is therefore to provide the scarfing starter device according to the preamble of the main claim so that no costly Measures on the workpiece support for the necessary formation of the scarfing start circuit more are required and, moreover, the scarfing machine regardless of your Position on the track and in relation to the respective workpiece electrical, flying scarfing start.

This is according to the invention according to the characterizing part of the main claim solved.

Further advantages of the invention emerge from the subclaims.

The inventive arrangement of the positive pole (starting electrode = Negative pole) also on the scarfing machine either directly in the area of the scarfing burner or on a separate auxiliary portal attached to the scarfing machine and thus with this can be moved in an advantageous manner without complex cabling measures of the workpiece supports one below the other, always an optimal scarfing start by means of the electrical scarfing starter can be achieved at any point within the scope of the scarfing machine, which is particularly important with selective scarfing is cheap.

The following description of preferred embodiments serves in connection with the attached drawing for further explanation. In this The drawing is shown, in FIG. 1 a schematic arrangement of the workpiece support and scarfing machine with a known polarity Scarfing starter (State of the art); 2 shows a basic sketch of the scarfing starter device according to the invention; Fig. 3 is a front view of a scarfing machine including the invention; Fig. 4 a top view of Fig. 3; FIG. 5 shows a sectional view of the positive pole and FIG. 6 shows another embodiment of the invention.

1 illustrates a conventional design of the scarfing starter device in terms of the electrical circuit.

As can be seen, a scarfing machine 10 is provided on guide rails 12 is arranged to be movable. Between the guide rails rests on a stationary one Support 14 the workpiece 16 to be flamed (e.g. a slab), which during the Scarfing process by means of the likewise movable (vertically and horizontally) scarfing burner 18 is "run over" by the machine. For a quick scarfing start (more flying Start) is a start electrode on the scarfing machine 10 in the area of the scarfing burner 18 20 provided. In order to have a closed circuit (starting electrode 20 workpiece 16 / support 14 - power source 22 - starting electrode 20 - are to be obtained as is known, the parts of the support 14 supporting the workpiece with one another and connected to an additional guardrail 24 via lines 26.

Via a sliding contact that is always in contact with the guide rail 24 28 the connection to the power source 22 is established. So that is the circuit closed.

As the arrangement shown in simplified form in FIG. 1 shows, it is necessary to have such a circuit over the entire tongue of the flame path, z. B.

100 m and more to maintain, which is especially for the selective Flaming of! Tightness is, because it is at any point along the gessnten flame path can be started.

This requires complex "connection work" for the necessary Circuit for the scarfing starter.

The inventive starter device shows the principle sketch 2. As can be seen, the starting electrode is also in the area of the flame burner 18 20, e.g. B. a carbon electrode (negative pole) is provided.

Instead of a carbon electrode, a metal electrode can of course also be used Find application. The other pole 30 (positive pole) required to form the circuit is arranged according to the invention in the area of the start electrode 20 and that this is carried directly by the scarfing machine 10, either by means of an auxiliary portal 34 (FIGS. 3 and 4) or via a height adjustment device provided in the area of the scarfing burner 10 62 (Fig. 5).

The starting electrode 20 and the positive pole 30 are connected to the cable 32 via the cable 32 Power source 22, in the example a Transfcrnator connected.

Due to the advantageous close arrangement of starting electrode 20 and Positive pole 30, the starting current is not opposed to such a great resistance (by the workpiece), as was previously the case with the prior art.

In Figures 3 to 5 is a preferred embodiment of the invention shown. As ersidtlic'a, the Flimmasoline 10 is both on the boom 36 transversely - as well as height-adjustable - the scarfing burner 18 (in the exemplary embodiment a Double flame burner) arranged. Each of these scarfing burner parts, which can be switched separately are assigned their own start electrode 20, which is shown in FIG Lines are connected to the power source.

On the scarfing machine, as shown in FIG. 4, in front of the scarfing burner 18, the auxiliary portal 34 is attached. This consists of two longitudinal members 38, between which a cross member 40 is provided. This cross member is used to accommodate the other poles / plus pole 30. Each workpiece processing path is assigned a plus pole 30, which are arranged on the cross member that they are above the respective support 14 are provided for the workpiece 1.6, as illustrated in FIG.

Of course, it is also possible and is advantageous Way to provide only a single positive pole within the scope of the invention, which then Arranged transversely movable on the cross member 40 and movable together with the scarfing burner is.

In Figures 3 and 4, the two positive poles * 30 are stationary on the cross member 40 provided and via cable 32, copper rails 32 a (Fig. 4) to form the circuit connected to the power source.

Fig. 5 shows the positive pole 30 on an enlarged scale. For height adjustment the plus nole is attached to a cross member 40 (pneumatic 1 'hv-? rallSisch) 51erstellylinder 42, 'which via lines 44 with a pressure medium source tied together is. This adjusting cylinder is surrounded by a protective housing 43. The one from the Adjusting cylinder protruding lower end of the cross member 40 penetrating The actual positive pole 30 is assigned to the piston rod 46. This exists in the exemplary embodiment essentially from a contact tip 48, which preferably consists of one of the current a highly conductive material such as copper. This contact tip is via a connector 50 to the cable 32 and the copper bars 32a to the other Positive pole or the power source connected. The lower end of the piston rod 46 is received by a receptacle 54 which (54) contains an insulator 52 (e.g. a plastic insert) wearing. This insulator is at the end of the receptacle facing away from the piston rod 46 54 arranged at a distance and is used to hold a contact tip 48 supporting Bolt 49. The isolator ensures that no current is undesirable from the Positive pole to cross member, adjusting cylinder etc. flows. The adjusting cylinder 42 is used for vertical adjustment of the positive pole 30. At the beginning of a scarfing start, the Adjusting cylinder 42 is actuated and thereby moves the positive pole 30 out of its upper one (Fig. 3) Starting position downwards until it comes into contact with the workpiece 16.

Simultaneously with this adjustment, or also somewhat delayed, is the start electrode 20, which is also by a specially not shown height adjustment device is held, moved downward until it is also in contact with the workpiece surface got. After switching on the power for the scarfing start and the slow take-off the starting electrode 20 of the workpiece 16 is an arc between these (16/20) drawn, through which an ignition and melting of the material in the area of the desired scarfing start point takes place. By switching on the scarfing oxygen and simultaneous forward movement of the scarfing machine is now the weld pool on the desired Flaming width worked out and the flaming process started.

After the scarfing start has taken place, both the start electrode 20 and also the positive pole 30 withdrawn in its starting position upwards, so that no Damage to these parts due to the scarfing slag produced during scarfing can be done.

The fixed arrangement of the positive pole 30 on the auxiliary portal 34 offers especially in the case of full-surface flames.

If, in particular with large-area workpieces, only a selective one Defect flaming is required, it is advantageous within the scope of the invention to use the Positive pole 30 to the respective fault location on the workpiece in relation to the scarfing burner 18 and align the starting electrode 20.

This is done in an advantageous manner either in the same way as before mentioned - that the positive pole 30 is not only adjustable in height but also transversely movable is formed on the auxiliary portal 34. This makes it possible to pinpoint the positive pole exactly Align the flaw on the workpiece, together with the likewise in connection Start electrode that can be moved transversely with the flame burner.

The common control and operation of the scarfing starter 20, 30 shows a further embodiment according to the invention, as shown in FIG. 6. The starting electrode 20 and the positive pole DO are according to this embodiment of FIG Holding tongues 55 added, separated by a current isolator 58 from each other so that there is no direct contact between the start electrode and the positive pole, but the circuit can only be closed via the workpiece 16, starting electrode 20 and positive pole 30 are carried by a common Verstellarn 60, which in turn is received by a height adjustment device 62. The height adjustment device is - as Fig. 6 shows - attached to the scarfing burner holder 64 and serves to the scarfing starter 20/30 about the axis of rotation 66 upwards (Ruiiste ilung) or downwards (rnrlänr.'starts division) to pivot. Rite.native but it is also possible within the scope of the invention, the adjusting arm 60 fixed to the To arrange height adjustment device 52 and this on the flame burner holder 64 vertically adjustable to be trained.

In the case of the pivotability of the scarfing burner 18 for the purpose of Scarfing the vertical side wall 16 a of the workpiece, cf. in this regard Fig. 3, the fl $ mmstarting device 20/30 in this lateral position is also advantageous with pivoted, so that thus also zin flying scarfing start on the side surface 16 a of the workpiece, Duych can design the scarfing starter according to the invention, especially the direct arrangement of the positive pole on the scarfing machine is advantageous wise no more connecting the support 14 to the circuit for the scarfing start necessary. This makes it possible to move anywhere in the travel range the Flärrirnmaschine a flying scarfing start by means of the electrical scarfing start set up. In addition, through the direct mutual spatial close arrangement of positive pole and negative pole the current for the scarfing start not so big Opposite resistance (workpiece).

Claims (6)

P a t e n t a n t a n t p r ü c h e 1. Scarfing starter device on a scarfing machine for the thermochemical processing of the surfaces of workpieces, consisting of essentially from a starting electrode assigned to a scarfing burner (first pole) which is connected to a current source, characterized in that it is used for formation The other pole 30 required of the circuit is also provided on the scarfing machine 10 is. 2. Scarfing device according to claim 1, characterized by a additional, the workpiece 16 to be bridged and at the scarfing machine 10 attached auxiliary portaf 34 on which the other pole 30 is arranged. 3. flame starting devices according to claim 1 and / or 2, characterized in that that the other pole 30 can be imagined vertically and / or horizontally on the auxiliary portal 34 is arranged. 4. Flamming device according to one of the preceding claims, characterized in that the other pole 30 together with the starting electrode 20 is adjustable. 5. scarfing device according to one of the preceding claims, it is noted that the other pole 30 and the start electrode 20 are arranged directly on the scarfing burner 18. 6. scarfing device according to one of the preceding claims, characterized in that the starting electrode 20 as the negative pole and the other pole al positive pole 30 is formed.