Rise fall of electrodes in mine hot stove is the method for control automatically
[technical field]
The present invention relates to a kind of rise fall of electrodes autocontrol method, especially relate to a kind of rise fall of electrodes in mine hot stove method of control automatically.
[background technology]
The hot stove in ore deposit, belong to a kind of of electric arc furnaces series, the product of smelting comprises that ferrosilicon class, silicomangan, chromium lack, calcium carbide, yellow phosphorus, corundum etc., the core theory that they are smelted is: form directed high temperature ion flow-electric arc by ionized air, convert electric energy to heat energy, for reduction reaction provides sufficiently high temperature field.
The state of electric arc depends on the temperature around electric conductivity, voltage and the electrode of distance, discharge body of electrode tip and discharge body and the resistance characteristic of furnace charge medium.In smelting process, continuous rising along with furnace bottom bath surface (or top of the slag), furnace charge is regular to be stayed, electrode tip is because of moving on the scaling loss and the variation of molten bath electric conductivity, need to adjust the physical location of electrode in good time, arc power can be in optimum condition all the time in the stove to keep, also want simultaneously to keep the in a basic balance of three-phase arc power, to keep the higher electrical efficiency that electric power system can reach, one of key that reaches this purpose is exactly that the rise fall of electrodes control system will have the better controlled performance, can discern automatically in the stove and change, state according to arc power in the stove is adjusted electrode position in good time, the primary heat transport system of pilot arc power two efficient meanwhile also will take into account the variation of charging resistance around the electrode.
The cold conditions ore is non-conductive, and the molten state mixture is a good conductor of electricity, and these characteristics have determined the complicacy and the difficult point of rise fall of electrodes in mine hot stove control system, also is numerous forerunners that are engaged in ore deposit hot stove robotization control the cause for the success places not yet so far.Up to the present, domestic existing rise fall of electrodes in mine hot stove is commonly control manually, when electric current during greater than setting, promote electrode, when electric current during less than setting, the decline electrode, individually the methods with PLC control also are based on the method identical with manual control, its major defect is that manually-operated randomness is big, labour intensity big, three-phase power imbalance, power consumption height, yield poorly, ore recovery ratio is low.
The factor that influences the mine heat furnace smelting power consumption is a lot, at first will solve the stable problem of thermal source, by the position of computer control three-phase electrode in stove, guarantees stove endogenous pyrogen equalization stable; Solve the homogeneity question of material then, preferably also control with computing machine.This two big factor is the key whether hot stove in ore deposit economizes on electricity, and the space of integrated power-saving is about 15%.The space of about 6% to 10%, the second factor in the space of first factor about 4% to 7%.Therefore, the condition precedent that obtains low power consumption be electrode must insert enough dark.If electrode is inserted not go down, and must be the power consumption height, yield poorly.The electrode insertion depth should be between 1000 to 1400 millimeters.
Chinese patent 93217672.0 discloses a kind of electrical arc furnace electrode lifting drive, and this device adopts the lifting of fluid motor-driven electrode, and the keying of this oil motor realizes control by the servo-valve in the control circuit.Its shortcoming is to adopt simulating signal to control, and its control accuracy is not high, can not reach the purpose of economize on electricity.
[summary of the invention]
In order to overcome the above-mentioned shortcoming of prior art, the invention provides the method that a kind of rise fall of electrodes in mine hot stove that can reduce melting electric consumption, boost productivity and improve ore recovery ratio is controlled automatically.
The technical solution adopted for the present invention to solve the technical problems is: a kind of rise fall of electrodes in mine hot stove is the method for control automatically, comprise transformer, the elementary or secondary current transformer that is equipped with at this transformer, the ac current signal that this current transformer is exported, be transformed to the DC voltage simulating signal through signal converter, offer the A/D sampling plate; Another road three-phase alternating voltage signal is directly taken from the ac voltage signal on the transformer secondary output outlet row, is transformed to the DC voltage simulating signal through signal converter, offers the A/D sampling plate; The A/D sampling plate is that six way word signals supply Computing with above-mentioned six tunnel DC voltage analog signal conversion, simultaneously hand control switch signal and spacing gauge tap signal is carried out computing by I/O input/output board access computing machine;
The machine output signal of carrying out after the computing transfers to frequency changing driving system or fluid power system respectively as calculated, that is:
The output signal of computing machine through the traffic direction of I/O input/output board outbound course signal controlling frequency converter, output signal to the relay output board, detent through conversion rear drive motor, electrode remains static when guaranteeing the frequency converter no-output, the D/A signal transducer becomes simulating signal with the switching value conversion of signals of computing machine, the output frequency size of control of conversion device, by the upper and lower motion of motor drives electrode lifting mechanism drive electrode, thus the size of electric power in the change stove;
The output signal of computing machine outputs signal to signal transducer through the I/O input/output board, amplify the rear drive solenoid movement through conversion, the upper and lower motion of hydraulic jack of control fluid power system, make the upper and lower motion of electrode by hydraulic jack drive electrode elevating mechanism, thereby change the size of electric power in the stove.
The input power supply of described transformer is to access to primary by electrical network 10KV or 35KV or 110KV three-phase alternating current through disconnector, vacuum switch, after conversion at the three-phase alternating current of secondary output 80V to 500V, join by the short net in the heavy in section of forming by heavy in section copper pipe or copper coin, soft copper cable, electric installation and graphite electrode, enter in the stove, electric power is provided.
The ac current signal of the output of described current transformer is the 0-5 ampere, is transformed to the DC voltage simulating signal of 0-5V or 0-10V through signal converter, offers the A/D sampling plate; Another road three-phase alternating voltage signal is directly taken from the transformer secondary output outlet row, is the 0-500V ac voltage signal, is transformed to the DC voltage simulating signal of 0-5V or 0-10V through signal converter, offers the A/D sampling plate.
Described ten four road or 20 road hand control switch signals, the spacing gauge tap signal of Shi Erlu insert computing machine by the I/O input/output board and carry out computing.
When described motor rotates, releasing of brake, when motor stops, the detent braking.
Good effect of the present invention is: according to the requirement to voltage, electric current and power of mine heat furnace smelting product and technology, give computing machine (setting value) with the numerical value form of electric current or power, computer control system automatically detected in real time parameter value (voltage, electric current) carries out carrying out three-phase equilibrium and comparison operation with setting value after the A/D conversion, and carry out analysis and judgement according to mathematics of control model, control strategy and unusual working of a furnace model, send one group then and instruct to frequency converter (solenoid control module) and pilot relay.Frequency converter (solenoid control module) is transformed to respective frequencies, corresponding voltage and corresponding polarity with corresponding instruction, move up and down with drive motor rotation (hydraulic jack) and then drive electrode, change arc stream, watt level or disengaging are automatic and remind the operator to handle, make system's correction of deviation promptly, keep it and operate in the given range; The used frequency converter of the present invention is dedicated test controlling and driving parts, digital control, and built-in couple of CPU, nearly more than 90 of functions, all numeral is set (the solenoid control module is special-purpose controlling and driving parts); Sampling system is the real-time status of controlling object and detected value thereof to be sent into the key interface of computing machine, its reliability and accuracy are related to the control performance of system, the object of sampling in the native system is short net voltage and current, and sampling section comprises mutual inductor and transmitter; Computing machine is the core of The whole control system, and it is responsible for processing computing, the decision-making of controlling models, the unscented transformation (A/D) and the storage computing of real time data; Operation interface of the present invention is full menu in Chinese prompting, can see the actual numerical value and the wave pattern thereof of arc voltage, arc stream when system moves in real time, and when smelting the unusual working of a furnace of appearance, system can prompting operation person handle; When system breaks down, also can judge from the picture of display.
The present invention can accurately control the speeds match of melt and reduction reaction in the mine heat furnace smelting process according to the different smelting stages, reaches economize on electricity, volume increase and improves the purpose of ore recovery ratio.
[description of drawings]
The present invention is further described below in conjunction with drawings and Examples.
Fig. 1 is a control circuit block diagram of the present invention.
Among the figure: GK-disconnector, ZK-vacuum switch, B-transformer, L-current transformer, M-motor, LCD-display screen.
[embodiment]
Referring to Fig. 1, a kind of rise fall of electrodes in mine hot stove is the method for control automatically, it is elementary that electrical network 10KV three-phase alternating current inserts ore heat furnace transformer B through disconnector GK, vacuum switch ZK, after conversion at the secondary output 80V of transformer B three-phase alternating current to 500V, join by the short net in the heavy in section of forming by heavy in section copper pipe or copper coin, soft copper cable, electric installation and graphite electrode, enter in the stove, electric power is provided.
Input signal of the present invention has: at the elementary or secondary current transformer L that is equipped with of transformer B, the ac current signal of output 0-5 ampere is transformed to the DC voltage simulating signal of 0-5V (or 0-10V) through signal converter, offers the A/D sampling plate; Another road three-phase alternating voltage signal is directly taken from B level of the transformer outlet row, is the 0-500V ac voltage signal, is transformed to 0-5V or 0-10V DC voltage simulating signal through signal converter, offers the A/D sampling plate; The A/D sampling plate is that six way word signals are for Computing with above-mentioned six tunnel DC voltage analog signal conversion; Ten four road or 20 road hand control switch signals, the spacing gauge tap signal of Shi Erlu insert computing machine by the I/O input/output board and carry out computing.After machine was handled as calculated, output signal of the present invention transferred to frequency changing driving system or fluid power system respectively, specifically:
Frequency changing driving system: the traffic direction of I/O input/output board outbound course signal controlling frequency converter, output signal to relay output board plate, through the detent of conversion rear drive motor M, electrode remains static when guaranteeing the frequency converter no-output; The D/A signal transducer becomes simulating signal with the switching value conversion of signals of computing machine, the output frequency size of control of conversion device; Thereby realize that motor M drives the upper and lower motion of electrode lifting mechanism drive electrode, thereby change the size of electric power in the stove.
When motor M rotates, releasing of brake, when motor M stops, the detent braking.
Fluid power system: the I/O input/output board outputs signal to signal transducer, after conversion is amplified, drive solenoid movement, the upper and lower motion of hydraulic jack of control fluid power system, make the upper and lower motion of electrode by hydraulic jack drive electrode elevating mechanism, thereby change the size of electric power in the stove.
The setting value of control signal is input to the calculator memory storage by keyboard.
Design concept of the present invention is: according to electric current in the stove " rate of change " size, differentiate the arc power size, and then calculate the conductivity of furnace bottom conductive layer, determine the match condition of reduction reaction and melt speed.
Concrete control method is:
Work as I
t>I
If+ I
The dead band% and the HD second of delaying time be when effective,
If I
t-(I
If+ I
The dead band%) 〉=and UPCURRENTGRADE, electrode decline URC transfixion second, and delay time USB second, said process repeated then.In the USB process, if electric current satisfies I
t≤ I
If+ I
The dead bandThe situation of % then stops the USB process;
If I
t-(I
If+ I
The dead band%)<and UPCURRENTGRADE, electrode rises to electric current to be satisfied
I
t≤ I
If+ I
The dead bandTill the %;
Otherwise, the electrode transfixion;
Work as I
t<I
If-I
The dead band% and the LD second of delaying time be when effective,
If I
t-(I
If-I
The dead band%)>and CURRENTGRADE, electrode drops to electric current to be satisfied
I
t〉=I
If-I
The dead bandTill the %;
If I
t-(I
If-I
The dead band%)≤and CURRENTGRADE, electrode rising DPRR transfixion second, and delay time LSB second, said process repeated then.
In the LSB process, if electric current satisfies
I
t〉=I
If-I
The dead bandThe situation of % then stops the LSB process;
Otherwise, the electrode transfixion;
When electrode ran into upper limit, electrode can only descend and can not rise, if
I
t>I
If+ I
The dead bandThe phenomenon of %, and satisfy
I
t-I
IfDuring 〉=LIMITCURRENT, electrode is inserted URC second down, the transfixion and the USB second of delaying time, repeats said process then.In the USB process, if electric current satisfies I
t≤ I
If+ I
The dead bandThe situation of % then stops the USB process;
The size of parameter: CURRENTGRADE, UPCURRENTGRADE, LD, HD, URC, DPRR, USB, LSB, LIMITCURRENT value depends on the size of the kind of smelting, main-transformer power, the no-load voltage ratio relation of current sampling data.
When the present invention was applied to the silicomanganese smelting furnace, transformer efficiency 8000KVA, primary side voltage 35KV, electric current 132A, current transformer changed 150/5,800 millimeters of electrode diameters.The native system sampled signal------primary side three-phase current (taking from current transformer), secondary side voltage signal (directly obtaining), secondary side from transformer outlet row over the ground phase voltage 60V,
I
If=44350 (A) UPCURRENTGRADE=2500 (A)
I
The dead band=3% CURRENTGRADE=3500 (A)
LD=50 (beat) HD=50 (beat) 1 beat=0.13S
URC=12 (beat) DPRR=12 (beat)
USB=500 (beat) LSB=500 (beat)
LIMITCURRENT=2500(A)
When the present invention is applied to the phosphorus smelting stove, six strip electrodes, transformer efficiency 16000KVA, primary side voltage 35KV, electric current 264A, secondary side be phase voltage 260V, phase current 35500A, single electrode electric current 17750A over the ground, current transformer ratio 20000/5,600 millimeters of electrode diameters.Systematic sampling signal----secondary side six electrode currents (taking from current transformer), secondary side voltage signal (directly obtaining) from transformer outlet row:
I
If=17700 (A) UPCURRENTGRADE=2500 (A)
I
The dead band=3% CURRENTGRADE=3500 (A)
LD=50 (beat) HD=50 (beat) 1 beat=0.13S
URC=12 (beat) DPRR=12 (beat)
USB=500 (beat) LSB=500 (beat)
LTMTTCURRENT=1500(A)