SE461258B - PROCEDURE AND DEVICE FOR STARTING A MULTI-STRING CASTING PLANT - Google Patents

Description

40 2 Afêniigzsvësat itself to be a device, according to which within the filling level measuring range the electronic units serving at 85% of the measuring section serving for regulating the 85% of the measuring section show a control connection to the drain closures and a starter sensor connection to the deduction 70 % measuring distance a final starter connection to the deduction drive and a closing connection to the drain closure, for those molds that are not sufficiently filled. In this case, the given measuring range percentages are to be understood as area indications, which, however, may well be adapted to the present operating conditions while obtaining their profile.

The invention will be described in more detail below in connection with the drawings. In this case, Fig. 1 shows the principle diagram for a multi-strand casting plant at the beginning of the casting and Figs. 2-S graphically show different program processes during the beginning of the casting.

In Fig. 1, 1 is denoted by a casting vessel, from which a steel melt is supplied via an adjustable drain closure 2, an intermediate vessel 3 is supplied, which in turn has three drain closures in the form of slide closures 4, which control the flow of melt through casting tubes 5 into continuous casting tubes. , B, C. To this end, each slide closure is mechanically coupled to an actuator 6, the respective operating positions of which are maintained by a position meter 7. These casting tubes 5 extend with their free ends into the molds A, B, C, whose for normal operation set setpoint filling level 8 approximately at 85% of the measuring distance 9 is assigned one for each mold A, B, C has transmitter 10 and receiver 11 consisting of filling level measuring device, as indicated at the measuring distance 9.

Arranged after the molds A, B, C is a secondary cooling device, not shown for the sake of simplicity, and a subtraction device common to the strings 18, which has drive rollers 12, a drive 13, a drive guide 14 and a subtraction speedometer 15. The latter emits its measured values firstly to a drive control or regulator 14 and secondly to a processor 16 which, in addition to the measured values of the degree of opening of the slide closure 4, controls and processes the position meter 7 and the receiver 11 of the filling level measuring device 10, 11. The data obtained goes to a control computer 17 integrated in the processor 16, which delivers suitable control instructions to the slide closure 4 of the setting means 6 and to the control 14 for the string pulling drive 12-15. There, the deduction rate is fixed as constant, ie the strands 18 formed in the molds A, B, C are deducted by the common deduction or extraction unit 12-15% åšgB remaining velocity, which means that the pre-filling condition 8 arranged for the molds is only is controlled from the inlet side by means of the slide closure 4. In addition, the slide closure 4 is kept during normal casting in throttle position, in order to enable both increase and decrease.

Before the casting begins, the cold strands 18 in the molds A, B, C are inserted and the subtraction drive 13 is disconnected. The casting begins with the opening of the slide closures 4, which, depending on the strand shapes to be cast, are opened completely or only partially, so that over the cold strand heads 19 the filling levels 20 in the molds A, B, C are formed, which, however, rarely stand at the same level.

In particular, different duct cross-sections and thereby different outflow amounts per unit time are obtained from the casting tubes 5, since tapered to the respective flow channels for the intermediate vessel 3 and the slide closures 4 occur, for example by "bear" formation due to freezing of melt at insufficient duct heating. . Likewise, the viscosity is increased by the cooling of the liquid steel over longer running distances in the intermediate vessel.

A leveling at very different fill levels 20 takes place by throttling each slide closure 4 in whose associated mold A, B, C the filling level has reached a signal plane 21, which is at a height of preferably 10% of the measuring distance and is monitored from the filling level measuring device 10, 11. for controlling the slide closures 4 by means of the precessor 16 and the control computer 17. Likewise, the level equalization of the fill levels 20 for all the molds A, B, C is monitored, after the completion of which the control computer 17 switches on the subtraction drive 13.

Now, in the normal monitoring and control mode, the setpoint level 8 oscillates. If level equalization does not take place or only between two molds A, B, C, a control order is issued for switching on the subtraction drive 13 at the latest at a further signal plane 22 arranged within the measuring section 9 below the setpoint level 8 by the first filling level arriving there. At the same time, closing instructions are given to the slide closures 4, in whose molds A, B or C, whose actual filling levels 20 are still below the signal plane 21.

For the scar filling level 20 plotted in Fig. 1, the curve according to Fig. 2 then applies. Thereafter, after the simultaneous complete opening of all slide closures 4 at the beginning of the casting at time Ct, the scar filling level 20 has passed the signal plane 21 as first, the slide closure for the mold C 4 has passed CH TO TS 40 46 1 tillzšíšgpläge. From this moment, the filling levels in the molds A and B rise faster than the filling level in the mold C to the snapshot in accordance with Fig. 1, which has been achieved after a casting time t.

In the following Figures 3-5, the casting time continues until the oscillation of the stock filling level 8.

From Fig. 3 it can be seen that the signal plane 21 is first crossed by the scar filling level in the mold A at the time At, then by the scar filling level in the mold B at the time Bt and finally by the scar filling level for the mold C at the time Ct and the slide closures 4 are throttled accordingly. After throttling of the closures A4 and B4, an equal level is obtained for both scar filling levels A20 and B20 at 30, even before the throttling of the slide closure 4 for the mold C, whose scar filling level 20 is comparable to the scar filling levels A20 and B20 at point 31, at which the drive 13 switched on, preferably at 70% of the normal speed. As soon as the subtraction drive is running, a curve 32 with equal scar filling levels is formed, which is clearly flattened, which means that the scar filling levels rise more slowly until after the end of the casting time the control drill fill level 8 has taken place.

In the exemplary embodiment according to Fig. 4, the scar filling level B20 finds no common level with the scar filling levels A20 and C20, even though all the scar filling levels at times Ct, At and Bt have exceeded the throttle signal plane 21 and set at the scar filling levels C20 and A20 at 33. a further increase then reaches the two levels at the same time the filling levels C20 and A20 reach the second signal plane 22, on which the subtraction drive 13 switches on and finally passes into the set filling level 8, to which the filling level B20 after an increase crack at 34 after the casting time t reaches.

A similar process takes place in the casting start in accordance with Fig. 5, where the filling levels B20 and A20 after throttling the slide closures B4 and A4 rise to the signal plane 21 at time Bt and Att from common to the drive signal plane 22 and then to the setpoint level 8 at time However, when coupling the subtraction drive 13 as a result of the filling levels B20 and A20, the filling level C20 has not exceeded the critical throttle signal plane 21, but is even below the zero percent start for the measuring section 9, which has triggered an automatic closing of the slide closure. C4.

During such monitoring, continuous casting plants with a multi-strand deduction unit can be started reliably to the set-load level.

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Claims (3)

461 258 P a t e n t k r a v Procedure for starting a multi-strand continuous casting plant. in particular for casting a steel melt, from an intermediate vessel to several continuous casting molds by means of controllable drain closures, wherein the filling level in the molds within a measuring distance is kept at a filling level and the strands forming are drawn by a common deduction device at the same speed. characterized in that at the beginning of the casting, drain plugs (4) opened at the intermediate vessel (3) for casting are affected, as in each mold (A, B. C) above the cold string heads (19) rising level of filling (20) at a lower region of the first signal plane (21) of the measuring section (9), first the throttling of its drain closure (4) for equalization of all core filling levels (A20, B20, C20) and then the connection of the string stripping device, which in the event of non-equalization at ) the second signal plane (22) is completed by the first filling level occurring there (A20, B20. C20). Method according to Claim 1, characterized in that the drain closures (4) are automatically closed for those in molds (A. B. C) whose actual filling level (20) is still below the first signal plane after complete engagement of the stripping device (13). Device for carrying out a procedure according to any one of claims 1 or 2, characterized in that electronic units (10) serving within the measuring section (9) for regulating the setpoint filling level (8) intended for 85% of the measuring section (9) (10) ll, 16. 17) from 10% of the measuring distance (9), a control connection to the drain closures (4) and a starter sensor connection to the stripping device (13), further at 70% of the measuring distance (9) a final starter sensor connection to the deduction - the closing device (13) and a closing coupling to the drain closures (4), the molds (AB C) of which are not sufficiently filled.