PNEUMATIC CHARGER FOR FEEDING PULVERIZED AND GRANULAR MATERIALS INTO METAL MELTS

Abstract: A charger based on the principle of pneumatics for the transport of granular, pulverized inflammable and explosive materials, as well as materials of high density into the metal melt. The charger according to the invention consists of a wind-box (4) connected to the conical bottom of the material storage tank (1), of the cylindrical porous element (5) forming a structural unit therewith, of the exchangeably spacer (7), the tap (10) and the T-profile (11). The gas streaming through the porous element (5) is flowing into the bore of the spacer (7), carries the material particles with itself and the accelerated material arrives through the tap (10), by the aid of the T-profile (11) into the system of delivery ducts. In order to facilitate maintenance, the spacer (7) is connected to the wind-box (4) with a releasable bond (8).

Description: PNEUMATIC CHARGES FOR PEEDIff(3 PULVERIZED AN ' GRANULAR MATERIALS INTO METAL MELTS Technical Field The invention relates to a charger operated on the principle of pneumatics which is suitable for feeding granular or pulverized inflammable and explosive w»rt*-i- * *»-ϊ rt T ι-f ΛΛ t*t .*■•■» 1 1 n e_ τwr.-τ Λ*»» ol q /■> U»ή < -* -^ φMαή "ττ -I Λ -Ϊ-Λ <^^-h^T V iuckvOJ. -L,*-* α- * fc-O *» <3 - d ιu V^J. u .ύ VJJ. i-J..___£=, j-i. ucu i j -L. w u α_v y u_. . melts. Metallurgical processes used in metallurgy show a new trend of development. Λ considerable part of the processes have been relocated from the me allurgic 5 furnace into the ladle. One of the most important branches of the ladle- etallurgic processes thus developed is represented by the blowing technologies, in course of which the gas carrying the diverse materials is blown, resp, transported pneumatically into the metal bath. Background Art Aa a result of the process several material qualities not having been manufactured as mass-produced goods up to now can be produced in a large quantity, or production of traditional qualities can be rendered more economical. In dependence of metallurgic processes the materials to be blown vary in respect to chemical composition and grain distribution within wide ranges. Accordingly, grain size may vary from a few microns to SAD ORIGINAL several millimetres, while chemical composition may vary from the treating materials on calcium basis through, ground ferro-alloys to the granular alloys containing magnesium having a thermite character and being inflammable and explosive. In dependence of the quality of treating materials chargers of different structures are in use. In the initial period methods developed from mechanical feeders well proved in pneumat material delivery to mechanic-pneumatic modes of feeding, arriving at last to chargers based exclusively on the principle of pneumatics. The. most known equipment or treating steels is the blower available in sale with the trade-mark "SCANDINAVIA LANCERS" • In course of said technologies pulverized treating material having a calcium-silicon content is introduced pneumatically into the steel. The main part of the charger is a conical fluidizator, consisting of a dense screeing cloth and the nozzles with a small cross- section arranged behind the screeing cloth, which enables the uniform distribution of the gas. The equipment is operated with an indifferent gas, with argon, pressure prevailing in the tank amounts to 6-8 bars. In the fluidizator the gas gets mixed with the pulverized reagent. High pressure presses the mixture of gas and powder into the delivery pipeline and via the lancer into the metal bath.. Due to wear of thescreen and obstruction of the nozzles the fluidizator requires permanent maintenance. The powder tends to clogging in the tank, material to be blown cannot be stored for a longer time. further disadvantageous feature of the equipment lies in that it can be operated with high- pressure gas only. Another mechanical equipment is also known which is different from that specified above, in so far as it fluidizator is formed by a screening cloth arranged at an angle of 30° and it is provided with a lower dischar opening with variable cross-section. Speed of material strea is controlled by a mechanical feeder. In respect to construction this equipment is far more complicated, possibilities of failure are greater. At the same time vibrations of the mechanical feeder make weighing more difficult. The aforementioned equipments operate on the principle of fluidization. W en passing through the fluidizing element, the carrier gas transfers its pulse to the material grains to be transported. If the force resulting from the pulse is higher, than the effect resulting from the weight of the grains and the friction force arising inbetween, the particles are carried away the gas, accordingly delivery is performed. As a consequence, state of fluidization depends partly on the streaming conditions of the carrying gas, partly on the grainsize and density of the material to be transported. Accordingly, this condition cannot be realized with materials of large grain-size and density - e.g. with ferro-alloys - and if, with considerable difficulties only. If - inapite of the arising difficulties - the desired condition can be achieved, streams of high speed occuring in course of fluidization are considerably wear the fluidizing elements, simultaneously friction arising between the grains to be transported may lead to self- ignition. Hazard of fire and explosion increases with material having magnesium content. With these types inflammability is increased by the small grainsize and arising high speeds, being otherwise most advantageous for the fluidizing process. By these reasons alloys with magnesium content are blown in notfrequently. The aim of the invention is to develop a solution with which parameters of transport, so transport capacity, density of delivery, quantity of carrier gas are constant, while at the same time, in case of necessity these values could be easily changed to the desired extent and in dependence of mode of operation. The solution according to the invention is well adapted for the transport of materia with a grain size o-f 3 to 5 . mm and a density of 4 to 6 kg/ Construction of the equipment is resistant to increased lo occuring under metallurgical circumstances. Disclosure of Invention Accordingly, the invention relates to a charger operated on the principle of pneumatics, which can be characterized by a wind-box provided with a inlet stud, on the inner part of which there is a vertically arranged cylindrical element made of a porous structural material. The upper part of the box is connected to the material storage tank, while the lower part is closed with.a spacer having a cylindrical bore. The spacer is connected with a tap in a releasable manner, which on its part is connected with the pipelinesystem by means of a T-profile having an oblique branch, Brief Description of Drawings The invention will now be described in detail by means of a preferred embodiment of the invention, by the aid of the drawing enclosed, illustrating the pneumatic charger in a sectional view. Best Mode of Carrying out the Invention The material storage tank 1 receives the materia be transported, being a pressure-proof tank with a coni lower part and provided with an opening for material filling. The cone of the tank 1 ends in the flanged connection 2. The wind-box 4 i« forming a unit with the counter-part of the flange 2. Said wind-box is formed w the sleeve 3 which is clamping the porous element 5 at top, while the lower part of the element 5 is seated on bottom of the box » The box 4 communicates with the in ' stud 6 introducing the gas at a pre-set pressure. The mixture of gas and material is flowing through the cylindrical bore of the spacer 7. The spacer 7 is clamp with a releasable bond and it provided with the sealing Material flow is interrupted by the tap 10, while the mixture of gas and material flowing through the tap 10 streams by the aid of the T-profile 11 into the pipeline system. Gas in a controlled quantity is introduced into the inlet stud of the T-profile 11, whereas its output branch is connected to the injecting lancer through the delivery duct. As the T-profile 11 does not contain any structur element which would impede material flow, it does not e a higher flow resistance, than an average pipe tract. I such a manner it becomes possible to connect the feeders of two or more material storage tanks in series. This fact opens new possibilities in respect to blowing technology. The pneumatic charger according to the invention operates, as follows: ' .. Material storage tank 1 is filled with the materi to be blown, now the tap 10 is closed. After having close the filling opening, gas at a pre-set pressure is led to the tank 1 through the inlet stud 6. First one starts wit the diving of the lancer into the metal bath and simultan ly gas in a controlled quantity is introduced into the in stud of the T-profile 11, the pressure of which prevents penetration of metal into the inside of the lancer. In t lower position of the lancer, when it is already dipped into the metal bath, material feeding begins by opening t tap 10. Through the inlet ' stud 6 gas is streaming among material grains, through the porous element 5 to the spac Material grains to be found on the upper bevelled part o spacer 7 are carried away by the streaming gas. The gas- material mixture is considerably accelerated in the bore the spacer and arrives with a significant kinetic energy the T-profile 11. Taking into consideration that in respe to the proportion gas/solids this mixture is very dense, controlled gas quantity, as previously mentioned, is admi here. In such a manner it can be achieved that the mater arrives pneumatically from the storage tank to the metal bath through the delivery duct and the lancer. As the material to be transported is forwarded by its own weight to the spacer 7, it is to be considered a specifically advantageous, that feeding is independent o material density and grain size. Operational safety of the e uipment is far increa by the fact that in course of feeding no fluidization fl is -faking place, the porous element is neither mechanical nor abrasively loaded. Plows with a higher velocity are transferred to the spacer 7, which can be easily manufa ••■• from- a wear-resistant.struc.tural material. *. A the same the spacer 7 is clamped into the wind-box with a releas bond β, enabling an easy and quick exchange. The porous element 5 is a cylinder with a vertic axis, so powder fraction of the material to be delivere cannot deposit in the opening thereof, so required clea and maintenance are minimal. Delivery output is uniform, at the same time it , be easily controlled in dependence of mode of operation magnitude depends on the flow velocity having been deve in the bore of the spacer 7. Control can be easily perf without changing any structural element, simply by regu the pressure of gas streaming through the stud 6. In course of the blowing process, up to the full immersion of the lancer, the pressure of the streaming on the inlet side of the T-profile 11 prevents intrusi of metal into the inside of the lancer- The stieaming of t oaaterial to be blown begins in the lower position of the lancer, i.e. in a completely immersed position, with the opening of the tap 10. In contrast to known equipments, using the solution according to the invention accidents resulting from considerable squirting - occuring frequen with alloys containing magnesium - can be avoided. This phenomenon can be observed especially, if in course of t immersion of the lancer material is blown into low bath depth. The charger according to the invention yield seve new possibilities in the field ofblowing technology. In case, if the T-profiles 11 of the blowers of two or more material storage tanks are connected in series, a plural of metallurgic processes can be performed with the same equipment. In the immersed state of the lancer, by openin the--tap**10 -o-f-one or -of the othe^-tank*, differeht-*materia can be introduced one after the other, or by the simultan opening of the taps 10 mixing of the materials while blow becomes also possible. As it becomes obvious from all what has been said, inspite of the simple construction, the equipment perform all the functions required by the special circumstances o blowing technology in course of pneumatic transport. Some advantageous features of the invention will b demonstrated by the way of examples. Example 1 In course of the experiment calcium containing mineral material and — without lifting the lancer - magnesium containing auxiliary alloy were introduced by the aid of a blower with two storage tanks. Particulars of the treatment; grain-size density transport out mm kg/dπr kg/min Calcium containing material 0 to 4 1,8 - 2 8 Magnesium containing alloy 0 - 3,5 3,6 - 4,0 14 Materials were delivered uniformly into the metal bath, stoppage could not be observed. Example 2 In course of this experiment chemical composition of the metal melt was set by blowing ferro-alloy into the melt. Particulars of treatment: Grain-size 0 to 5 mm Density 4,8 to 5,0 kg/dm^ . Transport output 18 kg/min In course of blowing process no failure could be observed in material transport.

Claims: C L A I M S 1. Pneumatic charger for the transport of pulverized and granular materials into metal melts, c h a r a c t e r i z e d in that it comprises a wind-box (4) connected to the conical bottom of the material storage tank (1), a porous element (5) of cylindrical shape and arranged in a vertical position forming a structural unit with said wind-box, an exchangeable spacer (7), as well as the tap (10) communicating therewith, and a T-profile (11) with a three-way outlet. 2. Pneumatic charger as claimed in claim 1, c h a r a c t e r i z e d in that its cylindrical spacer (7) is formed with a concentric bore and the part of the outer mantle facing the porous element (5) is bevelled, while the spacer (7) is. fixed in the house having been formed in the wind-box (4) with a releasable bond (8) with the insertion of the seal (9). 3 * Pneumatic charger as claimed in claims 1 and 2, c h ar a c t e r i z e d in that it is connected via the T-profile (11) to a delivery duct or when connected in series with the T-profile (11) of another charger, diverse materials, can be mixed while being delivered, or it is well suitable for allowing the gas to stream.

Inventors: HOFFMANN ISTVAN, SOMOGYI BELA, HOFFMANN, ISTVAN, SOMOGYI, BELA
Applicants: CEGLEDI VAS ELEKTROMOS ES MUES, CEGLEDI VAS- ELEKTROMOS ES MUESZERESZIPARI SZOEVETKE
Application year: 1985
Main classification: C12C7
IPC codes: B65G53, C21C7, C22B9, F27D3