HU180437B - Method for making channel system inductors of network frequency - Google Patents

Abstract

The invention relates to the production, replacement, commissioning and the increase of the electrical power of the inductors for induction trough furnaces Prod. Of Cu in OFHC quality and Messinglegierungen.Durch the invention, the Erhoehung the Leistungsfaehigkeit the furnace and the life of the inductors The invention provides a very pure millbase containing at least 99.5% SiO 2 and which, after drying for 8 hours at 400 ° C., has a hardness of from 1 to 1.6% of Na &sub2; ! B & IND4! O IND7! existing sintering material was mixed, pulped in the dry state in the Induktorsgehaeuse, in the previously a prefabricated rohrfoermige channel template made of copper was inserted. Advantageously, the sintering material is up to max. 50% with H & ind3! BO & ind3! substituted.

Description

The present invention relates to a method for making and using network frequency channel channel inductors.

The current state of the art, internationally recognized copper smelting equipment is capable of receiving 20 to 50 tons of liquid metal. Melting furnaces are generally devices with interchangeable inductors with mains frequency, channel system, whereby the heating of the copper melt on the basis of induction is the secondary part of the transformer and the so-called. in an inductor channel system. Located in the center of the channel system is the installed iron core with its associated multi-threaded, insulated induction primary coil.

¹ The major part of copper smelting equipment consists of interchangeable inductor units located on the * mantle of the melting furnace; their number is variable, 2-6 pieces are usually found per equipment.

Inductors are usually made with a multi-part steel ramming template which is subsequently removed from the sewer system after ramming. The lower channel section is rectangular, the ascending branches usually have a circular cross-section. The lower part is removed through a hole in the crushed wall and the opening is closed with a plug. The risers are pulled upwards.

The most common type of inductor used is 50-55% Al ₂ O ₃ , 40-45% SiO ₂ , + 0-5% TiO ₂ + ZrO ₂ . The most well-known and internationally recognized ramming material is also known as Tasyl 217 Dry5.

The technical literature considered is as follows:

1. ASEA Journal 1968. Volume 41. Number 5.,

65-70. pages Bernt Oiausson, Furnace

Department:

ASEA quick-change inductors foor channel furnaces

2. Giesserei 56 (1969) No. 9. April 24, pp. 241-245 Von Fritz Iten, VDG, in Bülach and Max Riethmann in Fislisbach:

„Dér Rinnenofen im modernen Giessereibetrieb”

3. Giesserei 57 (April 9, 1970) pages 235-239 Frerking, W .:

'Feuerfeste Auskleidung und Betrieb von Induktionsrinnenöfen in Eisengiessereien'.

The above ramming material is mixed with 4.2-4.5% H ₂ O and, after 24 hours of aging, induction of the inductor begins. When the inductors are tilted, the ram material is spread 60 mm thick and then rammed back to 30 mm. The stripped part is scraped off and the next coat is then applied. At the end of the induction of the inductor, the channel templates are removed in the in180 437

180 437 duct housings, and after 6 days of air drying, which is carried out at operating temperature, the inductor must be placed in the drying room; After a further 3 days of air drying in the drying room, the resistors are threaded into the ducts and connected to a multistage transformer, which increases the voltage to 3 ° C / day and increases the inductor temperature and duct system temperature to 160 ° C. The inductor is held at this value for 6 days and then slowly reduced to 60 ° C by the slow return and maintained at this temperature for the day before being placed on the furnace body.

With the above procedure, after a very slow and cumbersome heating, only the plant has a usable inductor. Poor ramping, rapid heating, vibration, or impact during assembly will all cause damage to the inductor, not to mention that mounting to the furnace, even after "gluing" accelerated heating, can only cause the inductor to become liquid after 96 hours of heating. fill with copper and start operation.

The effect of voltage cracks during drying or heating occurs when the inductor is electrically loaded;

The present invention is based on the discovery that a high purity of at least 98.5% SiO _{2 is} used in the wet kneading process, which, after drying at 400 ° C for 8 hours, contains 1.0 to 1.8% H3BO3 material. Sodium metaphosphate (NaPO ₃ ), which is ground to a maximum of 30% of the prescribed and calculated amount of colorant, may be used to facilitate the dissolution of metal oxides that may adhere to the sewer wall; thereby reducing the softening point of the ram material; this is crucial for channel life. The graphite powder, which is ground to a flour content of 0.8 to 1.2%, is preferably added to the S1O2 rammer. The crushing is carried out in a dry state by inserting a pre-formed copper tubular channel template into the inductor box in both the lower and upper branches, providing the best and best efficiency and induction utilization.

The inductor thus prepared can be mounted directly on the furnace and, after heating the duct templates with a gas burner for 8 ^h , can be filled with liquid copper (C < 2 content 100 ppm) and after 48 ' The other melting furnace inductors do not interfere with the operation of the melting furnace, and once the metal has been filled, the melting furnace may be fully loaded.

The significance of the present invention is further enhanced by the recognition that, by omitting and eliminating the plugs which have been considered to date, electrical channels of rectangular cross-section of copper tube are used, thereby increasing the electrical load of the inductor and increasing the power density of the channel.

This is coupled with the addition of a new channel cross-section to increase the thickness of the rammed fireproof layer outside the channel without changing the centerline of the channel system relative to the previous system. The available electrical power increase is 10-15% higher than the previous inductor.

It is also advantageous to achieve mechanical strength of the inductor to prevent damage to the inductor during assembly, and the mechanical strength of the ramming material required for high metal pressure and intense metal flow in the duct such that, after completion of the ramming, 50 mm was removed and the top of the inductor was sealed with this rammer pre-mixed with 8% phosphoric acid. The resulting chemical bond is achieved by storing the barrier layer in a room having an air temperature of 30-40 ° C for 8 hours. During this time the accessories of the inductor can be assembled without further ado. Drying with 30 electric radiators may be used to facilitate chemical bonding. The phosphoric acid (orthophosphoric acid) used loses water upon heating at 160 ° C and is converted to pyrophosphoric acid according to the following reaction equation:

2HFO, = H /, P ₂ O ₇ + H ₅ O

The resulting pyrophosphoric acid is a glassy, translucent, hard material that provides the hardness and strength of the top and final tiles to resist various mechanical stresses during installation to the furnace body.

The process of the present invention can replace the inductor 45 and fill the new inductor with metal within 24 hours and, in the melting furnace, replacing the inductors previously located in a single row, may occasionally replace 1 to 1 defective inductor. The furnace 50 can be thermally thermostated by means of a gas burner located near the exchanged space and rotated from below the metal level without damaging the unchanged inductor. This increases the number of inductor exchanges and the economical use of inductors.

The technology described below for crushing and fabricating inductive housings of different types and designs of melting and heat furnaces used in industrial practice is unequivocally and universally applicable, so that the technology described in this example corresponds to several examples of inductor fabrication.

65 is illustrated by way of example.

-2180 137

Figure 1 is a schematic drawing of a sectional view of the inductor of the invention taken along line A-A in Figure 2.

Figure 2 is a plan view of the inductor of Figure 1.

Figure 3 is a schematic sectional view along line B-B of the induction melting furnace of Figure 4.

Figure 4 is a schematic top plan view of the furnace of Figure 3.

As shown in Figures 1 and 2, the inductor box 1 is embedded in the friction material 2 of copper, and the induction coil 5 with the iron core 4 is also interposed between the branches of the channel template 3. The top 6 barrier layers of the fissure, as described below, are reinforced with phosphoric acid.

3 and 4 as an example. induction furnace 7 inductor boxes are mounted on 7 furnace bodies. The furnace body 7 can be rotated on rotating rollers 8. The metering orifice 9, the orifice 10, and the outlet 11 serve to dispense and discharge the liquid metal 12.

The insertion templates (not shown in the drawing) for closing the channel templates 3 and the opening of the iron core 4 are made of copper. Deposit templates one. or in two places with a plastic interruption to prevent them from heating up themselves in the inductive force field.

The ramming material 2, comprising at least 98.5% fractionated SiCl 2, is preferably dried for 4 hours at 400 ° C or higher. In determining the amount, the amount of material required to be inducted in the inductor box 1 is taken into account.

After drying, mix in a Roller passage with 1.0% H3BO3 ground and 0.4% NaPOs in powder color guide. Additionally, 0.8% flour milled graphite powder can be added. We carry out asbestos insulation of the steel inductor box 1 and brick 1 row of 20 mm thick chamotte bricks on the wider side, and then start crushing. Punching is done with a hand-held tubular or flat, live-shaped ramming tool, continuously and dry. The layers are continuously spread at a thickness of 30 mm and kneaded. After wounding the deposited layer, the inductor box 1 is repeatedly tapped with a rubber hammer several times to facilitate compaction of the granules. When the total height of the inductor box has been folded in, the upper approx. The 50 mm layer is removed.

The remaining crushed material is dripped with phosphoric acid in an inductor box using a pad brush and the SiO2 rammer, previously moistened with 1% water and mixed with 8% phosphoric acid, is poured onto it. This wet part is hammered as a sealing layer 6 into the upper part of the inductor box 1 with a hammer hammer to meet the strength requirements of the sealing part.

The inductor is assembled with 4 iron cores and 5 induction tex coils. The inductor is maintained at a temperature between 30 ° C and 40 ° C for at least 8 hours to establish chemical bonding of the crushed surface.

After the installation, it is made of copper

We begin the installation of 3 channel templates by operating the coil cooling fans. This is required to avoid deformation of the copper coil placed on the primary coil and the slit sheet. After heating the duct system for 8 to 15 hours, the inductor is rotated below the level of the liquid metal 12 and, at a secondary voltage of 130 to 180 V of the transformer, which means minimal buckling demand, the ducting and color deflection of the new inductor channels is performed. During this period, the furnace can be filled with metal and the equipment can be operated under normal load of non-exchanged inductors.

After the color deflection time has elapsed, with constant monitoring of the values of the thermocouple integrated elements, a gradual increase in the inductor power can be started and after 6 days the inductor will be loaded with maximum power.

Claims (4)

30 Patent claims: 1. A method for producing an inductor for an induction melting furnace with interchangeable inductors with mains frequency, channel system, characterized in that: 35 pre-dried, preferably 400 ° C, fractionated bleach containing at least 98.5% SiCl 2, optionally moistened with phosphoric acid, milled with 1 to 1.8% H3BO3 colorant and 0.8 to 1.2% flour. gra40 and powdered in a dry layer into the inductor box into which a copper cross-sectional template with a corresponding cross-sectional shape is placed, while up to 30% of the calculated amount of said diverting material 45 may be ground with sodium metaphosphate (NaPO ₃ ). 2. A method according to claim 1, wherein the copper tube is rectangular. 50 3. A method according to claim 1 or 2, characterized in that, in order to compensate for the intense metal flow in the channel, the ramming material is pre-mixed with 8% phosphoric acid and crushed at the top of the inductor. 4. A process according to claim 3 wherein the chemical bonding is carried out using an electric heater.