JPH0675432B2 - Method and device for reducing horizontal vibration of electrode - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for reducing horizontal vibration generated during operation of an electrode mounted on a supporting frame of an arc furnace and vertically inserted into a furnace vessel, and An apparatus for performing the method.

[Conventional technology and its problems]

During the melting process of the arc furnace, especially during the melting of scrap iron, the electrodes move horizontally due to the current force and the mechanical reaction of the electrodes and the support frame. As a result, the relatively brittle graphite electrode is mechanically damaged and in extreme cases, the electrode is damaged. The danger of major electrode damage always arises when the electrodynamic vibration system is self-excited and vibrates in resonance with the natural frequency of the electrode and the support frame.

DE-A 2841857 discloses a device for preventing vibration of the electrode arms of an arc furnace with a braking device connected in series with an impedance adjuster.

A disadvantage of this device is that the impedance regulators connected in series operate exclusively with variations in current and voltage, so that the braking device can only operate if the electrodes themselves move. The current and voltage depend on the length of the arc formed vertically in the case of an arc furnace. Therefore, the impedance adjuster can only be activated when the horizontal movement of the electrodes reaches a size that clearly changes the vertical length of the arc. However, this means that the electrodes will already vibrate before the regulator is activated. Since graphite electrodes are extremely brittle, even slight vibrations can lead to damage.

Another drawback is the length of the controlled object. The change in arc length at the electrode tip is processed as a current or voltage signal by an impedance regulator and a braking element outside the furnace and further fed to a servo element, which drives the support frame and electrodes via a drive.

Furthermore, if the number of components required for adjustment is large, not only will the adjusting device become uncertain, but also the high sensitivity performance of detection and the responsiveness of the adjusting device will decrease.

[Object of the Invention]

The basic object of the invention is to eliminate the abovementioned drawbacks and to prevent electrode damage caused by horizontal vibrations independently of electrode adjustment.

[Means for solving problems]

This object is achieved according to the invention by the claims 1) and 5), the preferred embodiments being the claims 2) to 4) and 6). Through paragraph 10).

〔The invention's effect〕

According to the invention, the electrodes are forced to vibrate vertically by the vibrator, which prevents horizontal vibration of the electrodes in the resonance range.

The advantage of this method is that even before the electrode vibrates horizontally in the critical frequency range, the electrode can positively act on the vibration characteristics to prevent the electrode from being damaged.

The curvilinear form of the vibration forced by the vibrator can be freely selected. A quadratic curve form is also preferred in which the operating accuracy is increased by combining the oscillator curve with the regulator characteristic curve.

Assembly of the vibrator is simple. The vibrator can be fitted anywhere within the force flux of the electrode support.

The vibrator is applied to electrode height adjustment independently of impedance adjustment.

〔Example〕

FIG. 1 shows an arc furnace 6 containing a melt 7 and having an electrode 1 mounted vertically thereon. Electrode 1 is
It is detachably fixed to the support arm 22 by an electrode holder 23. The support arm 22 and the support column 21 form the support frame 2.

The support frame 2 and the electrode 1 can be moved vertically by means of a lifting device 4 consisting of a working cylinder 41, a control valve and pump 43, a tank 44 and a main conduit 45 attached thereto.

In the case of the impedance adjusting device 5 shown schematically, an impedance adjuster 51 is connected to the servo element 52.

The vibrator 3 shown in FIG. 1 is composed of electric components for controlling the servo element 52, and vertically moves the support frame 2 and the electrode 1 via the operating cylinder 41 by the servo element 52 and the control valve 42. Vibrate.

FIG. 2 shows the vibrator 3 connected to the control element 32 and operating the working cylinder 41 by means of a parallel conduit 46. The working cylinder 41 vertically vibrates the support frame 2 and the electrode 1.

FIG. 3 shows a structure in which the vibrator 3 is configured by a cam (elevating member) 31 that is a mechanical component that causes vertical vibration, and is fixed to the support arm 22 to hold the electrode holder. The oscillator 3 for reciprocating the electrode 1 by means of a cam 31 mounted vertically on 23 is shown in a simplified diagram.

In the embodiments shown in FIGS. 1, 2, and 3, the vibration frequency of the vibrator 3 and thus of the electrode 1 can be adjusted as desired. It is set in the range of 0.1 to 10Hz. Then, the amplitude of the vertical vibration of the electrode 1 is adjusted to a maximum of ± 10 cm.

[Brief description of drawings]

FIG. 1 is an explanatory view showing one embodiment of the device of the present invention, FIG. 2 is an explanatory view showing another embodiment of the device of the present invention, and FIG. 3 is another embodiment of a vibrator constituting the device of the present invention. It is explanatory drawing which shows partially. 1 ... Electrode, 2 ... Support frame, 3 ... Vibrator, 4 ... Lifting device, 5 ... Impedance adjusting device, 6 ... Arc furnace, 21 ... Strut, 22 ... Support arm, 23 ... Electrode holder, 31 ... Cam, 32 ... Control element, 41 ... Operating cylinder, 42 ... Control valve, 43 ... Pump, 44 ... Tank, 45 ... Main conduit, 46 ... Parallel conduit, 51 ...... Impedance adjuster, 52 …… Servo element.

Claims (12)

[Claims] 1. A method for reducing horizontal vibration occurring during operation of an electrode fixed to a support frame and vertically inserted in the arc furnace vessel, wherein the electrode 1 is a vibrating means provided outside the arc furnace 6. Is forced to vibrate vertically, in which case the frequency of this vibration is
And a method for reducing horizontal vibration of an electrode, which is selected so as to be higher or lower than a natural frequency of a mechanical vibration system including the electrode 1. 2. Method according to claim 1), characterized in that the vibration is adjusted in the form of a rectangular curve. 3. A method according to claim 1) or 2), characterized in that the vibration is adjusted to an amplitude of ± 10 cm at maximum. 4. A method as claimed in any one of claims 1) to 3), characterized in that the vibration is adjusted to a maximum frequency of 10 Hz. 5. An operating cylinder equipped with a support frame 2 comprising a column 21, a support arm 22 and an electrode holder 23 and vertically inserted into a vessel of an arc furnace 6 and having a pressing medium acting thereon. Servo element operated by 41 52
Lifting device 4 or mechanical lifting member controlled by
An apparatus for horizontal vibration reduction of an electrode, comprising: a support frame (3) 31; and a vibrator (3) for vertically moving an electrode by controlling an elevating device (4) or an elevating member (31). 6. The device according to claim 5, wherein the electrode 1 is vertically vibrated together with the electrode holder 23 fixed to the support arm 22 by the vibrator 3. 7. The vibrating device 3 comprises an electrode 1 together with a supporting frame 2.
Device according to claim 5), characterized in that it is connected to a lifting device (4) for moving. 8. The vibrating device 3 comprises an electrode 1 together with a supporting frame 2.
Device according to claim 7), characterized in that it is connected to a servo device 52 for controlling the lifting device 4 for moving the. 9. The vibrator 3 is constituted by a cam 31 which is a mechanical component that causes vibration, and any one of claims 5) to 8). The device according to. 10. A device according to any one of claims 5) to 8), characterized in that the vibrator (3) is composed of electrical components that control the servo element (52). 11. The vibrator 3 has a frequency of 0.1 to 10H.
Device according to any of claims 5) to 10), characterized in that it is adjustable in the range of z. 12. The device according to any one of claims 5) to 10), characterized in that the vibration frequency of the vibrator 3 can be adjusted.