SE421265B - UGNSKOMBINAT - Google Patents

Description

10 15 20 25 30 55 soo314O-4 Via- mïnsf a SÜYBbG-r AC inverter. By controlling power output taken to the induction furnace / ovens crane one quickly »ooh effectively level. efremlukcuationem from iiusbagsugnama and a 'mgefariigen constant power outlets are obtained from the mains. This solves the above. problems, and in addition, higher production and lower production costs are obtained, e.g. lower electrode consumption and shorter melting times in the arc suckers.

In a preferred embodiment of the invention, each induction circuit is connected oven (preferably of the crucible type) _to1l the mains via an AC voltage converter.

The invention is further described and exemplified below and in the accompanying figures, of which figure 1 * is a principle sketch, figure 2 a detail in The heating oven and Figure 5 are a sketch of the induction oven and its gear unit. apäimingsomrilcbare. Figure 4 shows an amg frame over ae different skeaenaßvia _ the use of the oven combination, Figure 5 a three-phase alternative and Figure Glltre induction coils, placed over the scrap basket.

According to the tig word, the oven combi set consists of two arcuate gugs 2, 3, connected to a commodity pammagånat 1 via var em transfer-manen, 5. nu natet 1, preferably a three-phase network is connected to a reactive power compensator (VAR, 6) for voltage stabilization and compensation of the reactive effects, connected via the transformer 7. This consists, for example, of thyristor-connected capacitors or phase-controlled reactor, possibly with. harmonic filter. The compensator for the active power film is shown via s (Figure 1), connected to the mains via the transformer 9. It consists of an alternating inverter and one of the induction sockets fed therefrom, preferably one per phase or a three-phase converter with a three-phase suction xz. You can also have. and 'compensator per phase and thus one induction suction per phase and optionally a three-phase arc stage or three single-phase arc furnaces Figure 5 shows an induction suction; 10, provided with the usual parallel It is connected to the mains via an AC inverter, including comprising two antiparallel-connected thyristors 12 (different connection alternatives) with different numbers of thyristors conceivable.) and a reactor 15, and inverters are connected to the network via. transformer-n 9.

The power fluctuation from the arc suction (furnace is measured in a known manner, and this measurement hall may be controlled. thyristor 12 so that a relatively constant torque spoken power output Pref is obtained. 10 15 20 25 30 3 as 14o-4 The reactive effects of arc sugars 2, 3 (U) and the active power components The sensor 8 (W) is compensated in phase with the reactive power compensator 6, which is also symmetrically meters the active effects. P from the arc suu (multiphase R, S, T or several single-phase) and induction furnaces, for example according to the conditions: Q (VAIÛRS "" (U + W) R + Q (U + W) S 'Q. (U + W) T) c (VARLST - - (-a (lev), + s (var), + Q (U + w) ._,) Q. (VAIÛTR “" (Q (u- * VÛR "Q (UWÛS + Q (UÅÜT)) The drive voltage converter 12-13 feeds three single-phase or one or more three-phase phase inductive scrap preheating devices _10 'according to Figures 5, 5 and 6._ The compensator 8 is regulated in phases so that the active effects. in arc xlgzzazna 2, 3 and the scrap heating ovens 8, 10 become constant according to these control conditions: PH (t) + Pw (t) à Pref or nmsmßmf- (Purums-Pur) Pwsr = 1/3 Pref - (- 1 = Un + ms + m) rvrrn = 1/51 = ref- (Pun-1> Us + m) ' Pu (t) is the arc suction power, Pw (t) the induction suction power and Pref total the effect. R, S and T are the three phases.

During the first stage (A in Figure 4) of the operation of the furnace combinator, the melting stage, the power to the preheating orifice / furnace 10 is controlled so that the tips for Pu (t) is compensated and Pref becomes relatively constant. The effect on expectations pw (t) is displayed in the dashed portion. V After a certain time, you move on to completion, ie the arc effect is reduced (stage B), and the tips become smaller, but the preheating of the scrap, which later to be charged in the arc furnace, continues (Pw). When bottling (service stage C), the arc suction effect is reset, and only preheating takes place.

The scrap heating furnace can consist of three vertical, single-phase induction hobs. ma: (figure s, 14, 15, 16) maa paranelikonaensators (17-19), connected to the three-phase network 23 via respective AC converters 20, 21, 22, for example of the same kind as shown in figure 3. The ovens 14-16 can also be one or more three-phase induction furnaces.

Claims (8)

a 10 152 '8003140-4 4 Ugnania. may be conical induction dough lugs 14-16 according to Figure 6 with openable bottom 25, placed in a row above a carriage 26 with scrap baskets 27. The ovens 14-16 are fed with scrap in a conventional manner. Then. the scrap is to be charged in. the arc furnace opens the bottom 25, and it preheated. the scrap falls into the scrap basket 27 under the oven 15 for further transport to the arc furnaces. The furnaces 14-16 for preheating scrap are conical with a wider bottom than the top to prevent the scrap from hanging. As the effect develops at the psriferin, the energy must be transported to the center. (The oven coil is displayed at 28). This is shown in Figure 2. The furnace is lined with perforated, hard brick in which. ducts 30 fizmes supply air., air is then sucked from the periphery towards the center and led away from the furnace in a vertical exhaust pipe 31. The plate package is shown at 52 een ugraepelen via ae. After purification, the heated air can be used either for local heating or as combustion air, for example for pouring preheating. The device according to * above can be varied in many ways within the scope of the following claims. "Pirmmicniv A furnace combination, containing at least one arc fuse, such as three single-phase, or one or more two- or three-phase light arc fuses (2, 5) connected to an AC network (1), characterized in that to the same. mains (1) is connected at least one inamcuienaugfi (io) for: warning of the anar, which is later to be charged in the arc suction, the latter connection taking place via mztnst controllable AC voltage converter (8, 12, 13). 2. A furnace combination according to claim 1, characterized in that each induction auger (10, 14-16), suitably career, is connected to the network via an alternating voltage converter. Furnace combinator according to claims 1-2, characterized in that each AC drive (12, 15, 20-22) comprises at least two anti-parallel thyristors (12) and at least one reactor (15). 8003140-4 4. A furnace combination according to claims 1-3, characterized in that the effect in induction furnaces is controlled on. such a way that the total alctiva. the power from the oven combination is kept 1 largest. possible extent constant according to desired reference values. Furnace combination according to one or more of the preceding claims, characterized in that a reactive power compensator (6) is also connected to the mains for compensating real reactives. power fluctuations. Furnace combination according to one or more of the preceding claims, characterized in that each preheating induction furnace (14-16) is located or can be placed above a scrap basket (27) for further conveyance to the arc furnace (s) ( 2, 5). Oven combination according to Claim 6, characterized in that the preheating induction furnaces are provided with an openable bottom (25) and, optionally, degassing pipes (31). 8. A furnace combirzate according to claim 7, characterized in that the lining of the furnace is provided with perforated brick (29) through which air is blown to transport the energy from the periphery towards the center of the furnace. IN