DE1962960A1 - Method and device for regulating the fill level of melt in molds of continuous casting plants - Google Patents

Description

- 226 "I- -

Process · -: -: '! ;; ηά IT installation; Rege la der Fullstandohöha von Jahiielze In molds from -Jtrfnggusdanlagen

The invention relates to the regulation of the filling band height of the melt in the mold of Jtrangguesanlagen, ui; i also uei decrease of the och;: ielsf; n "ufu can still operate the plant automatically.

· £ ii.. ': - uei In 3etr ieb-located systems bereits- a control öckaru · ,, in the first with a otopfenregelung the Füllct-tuaenciic ::, i..' The oollwsrt is regulated. As soon as the open | ne: .e: a .- ■■ pots from the. ·! Intermediate container of the mold executed -jch ' - ¹ C:! ^; E:, r;] narrow not r.iehr the required level in the mold, for example due to clogging of the outflow at the Sv: ieohenb ^ h ^: ' lver , is from the stopper control to eire. - .; jo - jgtr-ev; & lung switched. In the fume hood controller of the • is cn the strand adjacent driving roller set so regulated that the required F "lj..etyndrhühe by Vex'l ^ ngpür.ieri the Abzugsgeochv / lndigkeit the strand is maintained. Disadvantage of a derar- '■', '-L ^ fri-Λ li'. ^ Jelung, aas G at the moment of change from the 3top- . '■ - .. er - "^ elv.ng u.jn' the .ibaugt-regulation of the regulator for the suction control :;;: Λο ·! nool: not set to the required control position hpL, so that the result is initially a sudden drop or a sudden increase in the fill level in the mold in relation to the 'tol.lwürt However, if the i'ullcL .- <: 'id ;; hühe v / ü'i'de there is an immediate switch back to the .Jtopfunregelun-e, so that initially there is an unrest in the control ⁱ .; Nver'. 'is .ieidbar Außserdom is on reaching the Übergon.j.'uedliig ^ Nijen of the otopfenregelung to the hood control a ^h;.' uflgf-i U'jischalten from one another on the control circuit , Hin ijogc-nonnbes flutter, the consequence. This creates unmanageable. "TörunKfjn, such as a possible overflow of the melt over the upper edge of the mold during operation, which increased requirements for the overflow of the otranggusfmnlagen by the Detriebsia 1 boding t.

109826/053 9

BATH ORIGINAL

The inventor has now set itself the task to avoid these undesirable Stö'rungsursachen and a free of sequelae transition from the plug control? £ .n the From ^ to ensure ugsregelunr.

A control method is therefore used to solve the problem suggested, whereby jcids control loops, cl.h. the plug rule and the take-off control loop, in parallel over the entire Gless process are switched to working. The plug control loop and the withdrawal control loop can be used either one after the other or at the same time Effectively influence the control process.

Since with this rule procedure the deduction rule is the direct continuation the plug regulation with regard to the influence on the The control process is uninterrupted continued without the need to first set the fume cupboard control to the current actual value.

The two control loops of the plug and take-off control are parallel to each other, depending on the operating status normally first of all, the plug control circuit effectively influences the fill level of the mold. As soon as the stopper in the intermediate container the discharge the melt has completely released to the mold, v / ird the inflow of the amount of melt into the mold and the withdrawal of the strand via the withdrawal control brought into equilibrium. In practice, when there are rapid changes in the supply of melt quantity per unit of time, the two control processes overlap their own indolence.

It is therefore possible for control steps to be borrowed quickly the filling level of the mold and the stopper re & elmig alü, the deduction rules also take effect at the same time.

109826/0539

BATH ORIGINAL

The device for carrying out the control procedure consists of an integral controller, a so-called PI controller, as a zero controller in the dtorjfenrege! circuit and a proportional controller in the Abzusi; control circuit, which are parallel to each other with respect to the filling stick work.

Air v.-eir-ereü feature is a function in the extraction control loop via x '(Ah) = η -, ·, switched on. This function generator beotii:. '! Nt, at which ^ h the deduction regulation comes into operation. The giver can let the deduction regulation take effect at ^ h = 0, at A h \ 0 or be j / Ih ^ O. It is also possible that g of Funktioncgeber the hood control at 4 h ^ 0 einschaltot, "but hi'lt in the area around Ah = 0, the take-off speed constant and Δ. H * <0 the withdrawal speed of the strand again proportional to the level reduction Whether the draft control is already effective at a filling level difference A hf 0 or only when the filling level difference Δ h <* 0, i.e. below the setpoint 1 · ΐ _ςο11 , depends on the drawing speed with which the system is still drawing can be operated without any technical or metallurgical disadvantages.

The interpretation of the function generator determines at which Grosse of Δ h, the control range of the hood control is fully exploited, ie the like Absugsgeschwindigkeit check up is reduced to zero. The discharge control takes over the compensation of level differences Δ. In other words, by adjusting the withdrawal speed to that of the amount of melt flowing into the mold. The point in time of the transition from plug control to extraction control can be determined by means of the function generator, depending on the circumstances.

An exemplary embodiment of the invention is shown in the drawing. Ks show:

109826/0539

BATH ORIGINAL

Fig. 1 the control device in principle,

2 shows a diagram of the withdrawal speed as a function of the level of liquidity for becoming effective the deduction regulation at ZL h ~ G,

5 shows a diagram of the withdrawal speed as a function of the filling level for it to take effect the deduction regulation at Δ h * SC O,

4 shows a diagram of the take-off speed as a function of the fill level for a reversal of the take-off control when & h j> 0 and

5 shows a diagram of the withdrawal speed as a function of the filling level for a Ueffärmwerdan. the deduction control at A h ^ 0 "and a constant Take-off speed in the range around Δ h ~ 0

In these diagrams, the vertical was identified as an independent 7th Linder borrowed because the melt is in the operating state of the plant also moved in the vertical.

In Fig. 1, a continuous casting plant is shown in principle. This consists of an intermediate container 1, at the bottom opening of which there is an outflow pipe 2 which protrudes into a mold 4. In the intermediate container, a raised and lowered stopper Jt is "disposed usflussbYfnung Near the top opening of the ^mold..!; It-c" for selectively opening or the Schliesscn.. In the area of the outer walls of the mold 4, a radioactive emitter 5 and a receiver 6, for example a scintillation counter, existing level measuring device 7 are provided. The radiator 5 and the receiver 6 are opposite one another, while the level of the .Jchnielze in the mold 4 is monitored by measuring the respective radiation intensity of the radiator 5. The melt, which has cooled to form an endless strand 7 in the Kok-Hu 4, is lowered along a roller guide 8. The lowering speed of the strand ']' is determined by raar ^ n of drive rollers 9.

109826/0539

BATH ORIGINAL

1- generally the. '. Vaccine -.' Nger 6 is connected to an actual value gobar 11, which via a supply line 12 has a difference generator 13 for the ^; ■ ad ·; · -sens'tan Iotv; ert the level height h .. and via a supply line Vl : eU an adjustable setpoint adjuster 1'5 of the level height h _c . verbunctoa i.st. The plug control loop, which divides it, is connected via a feed line 16 to a PI controller 17, which represents an integral controller as a zero controller, an amplifier 18 and an actuator for the plug Z wit de ;; i differential value generator Y-) .

a v-ioitere lead 2o is the trigger control circuit consisting of a / i function generator 21, an amplifier 22 as the propor - '^ ionalrügelglied, a Differenzwertbildner 2p, a Tachogene- "r-.tox' 2 ~ j as Isüv / ertgeber for the speed n. of the drive rollers 9, d.-rr; iit the 'loüor 24 for driving the pairs of drive rollers 9 is mechanically / mechanically coupled, connected to the differential counter 13.

, 'The system works as follows:

'3EI filling the Zwischenbehlllters 1 with melt is training' on fluüüüffnung ^r jews of Z v / ischenbehälters one normally zurt oliis <& with the plug Z> closed up from a non \ ^ il - ') V ladle shown Lame ice poured into the intermediate container 1 has reached a sufficient height in the intermediate container 1. Then the plug 3 is first controlled manually ^ a v / enig raised, so that a certain quantity of melt in the mold ^ h can be incorporated and these rncteigt to dan in the region of the Strahiere ^l j. The automatic level control is then stopped. Thus, the pairs of driving rollers 9 initially pull the strand 7 with the level of the filling level in the mold K ; speaking take-off speed. As soon as the melt the; The target word that has reached the level h »becomes the plug 3 f with te Ir; the actuator 19 delivered ready, "that out-of flucj embodiment:; of the intermediate containers ^ 1 offiiung much melt in the co-{kille h; iufllasia that the sollv; ert uitv fill level height h ER- {hold ol ^ ibt Any. . '"nderurig-sn dm * level height Ab are

109826/0539

BAD ORIGINAt

Regulated back to Ah = O via the PI controller 17 as an integrator by actuating the actuator 19 and thus by changing the position of the plug ~ j in the outflow opening.

As soon as the outflow opening is due to so-called "freezing" more clogging and the stopper; of the actuator 19 so far "that has been moved out of the orifice via a Changing the plug position via the plug control circuit no longer has any influence on a compensation of the fill level change A ti zu take, the take-off control circuit takes over the coordination between the take-off speed and the amount of melt flowing in by the The casting level in the mold 4 drops accordingly and the withdrawal speed ν is accordingly reduced. This will be by converting the level change / a h into a corresponding one Speed change Δ η the drive of the driving roller sets 9 with respect to its speed is reduced so that an equilibrium between the inflowing and withdrawn amount of melt is achieved.

The deduction control loop comes into operation when deto Plug control circuit no more control of the level can be achieved, d, h. when the orifice is already high Added mass.

On the other hand, it may well happen that the plug control loop and the drawdown control loop take effect at the same time, which can occur, for example, if any momentary Malfunction, the fill level suddenly changes significantly in a positive or negative sense.

So if there is a positive change in level, i.e. if there is too much at. Melt, the stopper, 5 retracted by means of the actuator 19, so that the outflow opening is temporarily almost closed ■ is, while at the same time-the deduction regulation the pairs of driving-Γ · rolls 9 set to maximum take-off speed *;

109826/0539

BATH ORIGINAL

In the event of a negative level change, i.e. too little on Melt, the plug control is controlled by means of the actuator 19 completely extend the stopper 3 from the outflow opening, while the trigger control moves the pairs of drive rollers 9 to low levels ;; adjusts the eye speed.

The function generator 21 in the deduction control circuit, which is based on the function η = f (Δ h) the speed setpoint η for the pairs of drive rollers 9 also has an influence on the value of the level change A h at which the transition from plug control takes place the deduction regulation takes place.

The various options for the point in time of the transition from plug control to extraction control and the design the control process can be seen from the diagrams in FIGS. In the diagrams of FIGS. 2 to 5, the fill level change A h is on the independent variable and on the dependent one Change the take-off speed v "plotted.

From Fig. 2 it can be seen that the function generator 21 the transition from the plug control to the withdrawal control at A h - O, i.e. as soon as the level A h falls below the setpoint h has sunk.

In the diagram in FIG. 3, the transition from plug regulation takes place on the deduction regulation at Δ. h < 0, i.e. in the event of a level change that is already below the setpoint h des

Level is.

As can be seen from the diagram in FIG. 4, the ü from the plug regulation to the discharge regulation also with

0. This is only possible if the interpretation of the allows the string to be lowered more quickly without any disadvantages for the finished product or operational safety.

109826/0539

Experience has shown that one endeavors not to allow the transition from pot control to fume cupboard control to take place in the area where the level change Ah = 0, since in this area there can be relatively strong fluctuations between the amount of shrink being fed into the pot k per unit of time. This is related to the fact that the already clogged outflow can change its cross-section again to varying degrees, so that a larger amount of melt or also a smaller amount of ochmelzen gets into the mold 4 intermittently. Since the limit value for the transition from the pots control to the deduction control normally occurs in this area, a relatively large amount of unrest in the control must be expected. It is therefore preferred to set the transition values from the 3pot control to the withdrawal control by means of the function generator 21 so that the transition from the stopper control to the withdrawal control takes place either below Ah = 0 or from above ^ hO.

In a further diagram in FIG. 5, with a planned transition from the pot control to the extraction control at / ^ h / * Q, it is shown that by dimensioning the function generator 21 it is also possible to adjust the range around A h ~ ° ^ra it to pass through a constant take-off speed. V'i.'hrerxl already in the .positive area of A h the Aozujsgeechwindicktiit v. is controlled, this is kept constant when passing through the area Δ Ii = 0 and is only adapted to the inflowing .jschmelzennienge in the negative 'jerc-iah of Δ h.

The radio transmitter 21 normally consists of an interconnection of diodes and resistors, which may be connected become effective with amplifier stages.

109821/0539

BATH ORIGINAL

Claims (1)

- 2263 - Pc, tentc'.ns claims '' 1. Procedure for regulating the filling level of the melt in the : Killing of JtrangguGsanlagen, whereby the measured in the mold een-o · Filling level of melt section by section either through ; Regulating the stopper of the oily container or by rules the withdrawal speed of the strand over with its ■ ■ Scope of driving roller sets lying on the strand takes place and _t the plug control loop by means of a PI element as an integral λ ■ controller regulates on Ah = O, characterized in that the plug control circuit and the draw-off control loop work in parallel over the entire casting process, the draw-off control circuit is given the desired target draw-off speed v "for the pouring level deviation Δ h - 0 and, in the case of negative pouring level deviations, the value for the take-off speed ν up to the equilibrium between the amount of molten mass that is flowing in and the amount of molten flowing away, and in the case of a positive casting level deviation, the value for the draw-off speed v "up to the weight of the flowing-in and flow-off melt quantity increases, with the plug control circuit and / or the draw-off control circuit individually or jointly influencing the filling level Ah the melt in the mold. \ 2. A method for regulating the fill level according to claim 1, characterized in that only when the fill level drops to Äh · <O of the withdrawal regulation the filling level 4i h ref., - -.- ". ■ - ■■■" ^v: - \ ^; ". '. "-'"';':%> ■ ^: -: y ^!: ■ '."■; ..: 'J ■■' - ■. 'J). A method for controlling the Füilnfcandsfiöhe according to claim -1> DA / by gfckonrtzeioh net _# aueh that at £ k y * -o "kr61c the PUllötandohöho & regulates h. 109826/0539 BATH ORIGINAL - Io - 4, method according to claim j5> thereby gekemazeiclmei j that in area i
will. Area Ah = G the take-off speed ν kept constant 5 · Device for performing the ■ method iiacii one of claims 1 to 4, characterized in that the difference value calculator (lj3) from the nominal value of the fill level (ii _e ) and the actual value of the fill level h ^ an integral control * (17) (PI - or Nullwertreglef) in the plug control loop and a proportional control element (22) in the withdrawal control loop are naehgesctialtet. 6. Device naoh claim 5 for carrying out the method according to one of claims 2 to 4, characterized in that a function generator (21) is switched on in the take-off control circuit 109826/05 3 9 BATH ORIGINAL Blank page