Industrial electric heating furnaces – Arc furnace device – Plural furnace units
Patent
1999-09-27
2000-12-05
Hoang, Tu Ba
Industrial electric heating furnaces
Arc furnace device
Plural furnace units
373 79, 373 80, F27D 2300
Patent
active
061576646
DESCRIPTION:
BRIEF SUMMARY
FIELD OF APPLICATION
This invention concerns a system to load pre-heated scrap by means of baskets for an electric arc furnace.
The invention is applied in the field of steel production in order to load, by means of baskets arriving from the scrap storage zone or loaded directly in the pre-heating position, the electric furnaces with scrap, or other prime material similar to scrap, which is pre-heated by means of the fumes coming from the said electric furnaces.
The electric arc furnaces to which the invention is applied can be of the type fed by alternating or direct current.
The invention makes it possible to reduce the times needed to open the roof of the furnace in order to load the furnace, thus limiting the heat losses from inside the furnace towards the outside environment.
Furthermore, the invention makes it possible to load the furnace with scrap which has been heated in the same moving basket used to unload the scrap into the furnace.
Moreover, the invention makes it possible to automate the movements needed for loading, to drastically reduce the times of the cycle, and therefore reduce the downtimes of the furnace, and minimises the spaces required, both horizontally and especially vertically, in order to carry out the pre-heating and loading operations.
The invention may be used both in new installations arranged for the purpose and also in the revamping of existing installations using conventional-type furnaces.
STATE OF THE ART
The state of the art includes electric arc furnaces used to produce steel from scrap and regenerated material of various types.
In the state of the art, the furnaces can be loaded continuously, for example by means of conveying means such as a belt, connected with the inside of the furnace and fed continuously with fresh scrap which gradually replaces that already loaded into the furnace.
In another solution, the furnaces are loaded discontinuously by means of baskets which, in one or more steps, are loaded in a scrap-loading zone and then transported, by lifting and moving means, for example by bridge cranes, in correspondence with the mouth of the furnace which is kept temporally open. The bottom of the basket, which normally consists of movable doors, valves, teeth, sliding retaining grates or other opening systems, is then opened and the material is unloaded inside the furnace.
Systems using baskets for loading the furnace which are known to the state of the art have a plurality of disadvantages.
Firstly, it takes a long time to load the furnace because of the combination of opening movements of the roof and positioning of the baskets; this causes a considerable heat loss from inside the furnace towards the outside, and also the leakage into the surrounding environment of fumes containing powders, particles and other pollutants.
A further disadvantage is that if the scrap is loaded cold into the furnace, it takes longer to melt and causes problems for the penetration of the electrodes.
At present, in some steel plants the furnaces are loaded with scrap which is pre-heated by the heat of the fumes discharged from the furnace itself through the fourth hole on the roof.
Loading systems known to the state of the art where the scrap is pre-heated use loading baskets located in the appropriate rooms into which the fumes are conveyed before they are purified and discharged by the appropriate plants.
There are also solutions known to the state of the art which include a single room which contains several loading baskets, or several rooms connected to each other, each one of which contains a single loading basket. These solutions cause problems in the structuring of the rooms, the movements of the baskets and wear on the baskets too.
Moreover, in the case of baskets heated inside the room, the scrap loses part of the heat it has accumulated, both when it is removed from the room and when it is transported to near the mouth of the furnace and also when it is unloaded into the furnace, from which there is always and in any case a considerable heat loss. The scrap moreover
REFERENCES:
patent: 2804295 (1957-08-01), Brooke
patent: 3385584 (1968-05-01), Kemmetmueller
patent: 4160117 (1979-07-01), Schempp
patent: 4390168 (1983-06-01), Muller
patent: 4506370 (1985-03-01), Yoshimatsu
patent: 4736383 (1988-04-01), Meierling
patent: 5106063 (1992-04-01), Granstrom
patent: 5390212 (1995-02-01), Bonnet et al.
patent: 5416792 (1995-05-01), Vice
patent: 5602867 (1997-02-01), Hubers et al.
patent: 5628958 (1997-05-01), Frank
Benedetti Giampietro
Della Negra Angelico
Gensini Gianni
Pavlicevic Milorad
Poloni Alfredo
Danieli & C. Officine Meccaniche SpA
Hoang Tu Ba
LandOfFree
System to load pre-heated scrap by means of baskets for electric does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System to load pre-heated scrap by means of baskets for electric, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System to load pre-heated scrap by means of baskets for electric will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-968005