CN107682950B - Power constant system capable of automatically adjusting electrode position and working method thereof - Google Patents

Abstract

The invention relates to a power constant system capable of automatically adjusting electrode positions and a working method thereof. Compared with the prior art, the invention realizes constant power of electric furnace smelting by using the thought of automatically adjusting the electrode position, and greatly improves smelting production quality and efficiency.

Description

A power constant system that can automatically adjust electrode positions and its working method

Technical field

The invention relates to the field of electric furnace steelmaking, and in particular to a power constant system that can automatically adjust electrode positions and a working method thereof.

Background technique

When making steel in electric furnaces, the design of a constant-power electro-hydraulic servo system that controls the lifting and lowering of electrodes has always been a major technical problem that plagues quality improvement. Fast and accurate electrode position control is one of the key factors to save electric energy, shorten the smelting cycle, reduce electrode consumption and extend the life of the furnace lining.

During enterprise smelting, because the electrode position cannot be automatically adjusted, the current and voltage fluctuate excessively, resulting in many shortcomings such as long smelting time, reduced output, increased power consumption, and increased electrode consumption.

Contents of the invention

The purpose of the present invention is to provide a power constant system that can automatically adjust the electrode position and its working method in order to overcome the above-mentioned shortcomings of the prior art. By using the idea of automatically adjusting the electrode position, the constant power of electric furnace smelting is realized, which greatly improves the efficiency of electric furnace smelting. Improve the quality and efficiency of smelting production.

The object of the present invention can be achieved through the following technical solutions:

A power constant system that can automatically adjust the electrode position, including a current transformer for detecting electrode current, an isolation transformer for detecting electrode voltage, a first rectifier, a second rectifier, a first sliding rheostat, and a three-position three-way servo valve, plunger cylinder, oil return oil circuit and oil injection oil circuit, the output end of the current transformer is connected to the input end of the first rectifier, the output end of the isolation transformer is connected to the input end of the second rectifier, the first The first output end of the rectifier is respectively connected to the first output end of the second rectifier and the sliding end of the first sliding rheostat, and the second output end of the first rectifier is respectively connected to the first end of the first sliding rheostat and the three-position three-way servo valve. The first signal input end, the second output end of the second rectifier is respectively connected to the second end of the first sliding rheostat and the second signal input end of the three-position three-way servo valve, and the oil chamber of the plunger cylinder is connected to The first interface of the three-position three-way servo valve, the driving end of the plunger cylinder is connected to the electrode, the second interface of the three-position three-way servo valve is connected to the oil return line, and the third interface of the three-position three-way servo valve is connected to the oil injection In the oil circuit, the left position of the three-position three-way servo valve conducts the oil chamber and oil filling circuit of the plunger cylinder. The middle position of the three-position three-way servo valve does not conduct. The right position of the three-position three-way servo valve conducts the plunger cylinder. Oil chamber and oil return line.

It also includes a second sliding rheostat and a third sliding rheostat, the first output end of the current transformer is respectively connected to the sliding end of the second sliding rheostat, the second end of the second sliding rheostat and the first end of the third sliding rheostat, The second output end of the current transformer is respectively connected to the first end of the second sliding rheostat and the second input end of the first rectifier, and the sliding end and the second end of the second sliding rheostat are both connected to the first input of the first rectifier. end.

It also includes a fourth sliding rheostat, the first end of the fourth sliding rheostat is connected to the second output end of the second rectifier and the second end of the first sliding rheostat respectively, and the sliding end and the second end of the fourth sliding rheostat are both connected. The second signal input terminal of the three-position three-way servo valve.

The return oil circuit includes a first accumulator and a first safety valve. One end of the first accumulator is connected to the second interface of the three-position three-way servo valve, and the other end of the first accumulator is connected to the first One end of the safety valve and the other end of the first safety valve are connected to the oil tank.

The oil injection oil circuit includes a second accumulator, a second safety valve and an oil pump. One end of the second accumulator is connected to the third interface of the three-position three-way servo valve and the output end of the oil pump respectively. The second energy accumulator The other end of the device is connected to one end of the second safety valve, and the other end of the second safety valve and the input end of the oil pump are both connected to the oil tank.

A working method of the above-mentioned power constant system that can automatically adjust the electrode position includes the following steps:

S1: Adjust the position of the sliding end of the first sliding rheostat so that when the electrode current and electrode voltage are the required values, the voltage difference between the two ends of the first sliding rheostat is zero. At this time, the three-position three-way servo valve is in the neutral position and the electrode position Stay still and maintain a state of balance;

S2: When the three-position three-way servo valve detects that the first terminal voltage of the first sliding rheostat is less than the second terminal voltage, the three-position three-way servo valve switches to the right position. Under the action of the self-weight of the motor and plunger cylinder, the liquid flow The oil chamber of the plunger cylinder flows into the return oil circuit through the three-position three-way servo valve, and the electrode descends with the driving end of the plunger cylinder until it returns to the equilibrium state;

When the three-position three-way servo valve detects that the first terminal voltage of the first sliding rheostat is greater than the second terminal voltage, the three-position three-way servo valve switches to the left position, and high-pressure liquid flows from the oil injection path through the three-position three-way servo valve. In the oil chamber of the plunger cylinder, the electrode rises with the driving end of the plunger cylinder until it returns to the equilibrium state.

Compared with the prior art, the present invention has the following advantages:

1. The present invention sets up a comparison circuit composed of a current transformer, an isolation transformer, two rectifiers and a sliding rheostat. During the entire smelting process, as long as the arc voltage and current deviate from the predetermined values, the servo valve operates, and the electrode will automatically rise or fall. , thus keeping the melting power constant and greatly improving the melting quality and efficiency.

2. The present invention has a high safety factor and has strong guiding significance for the production of smelting enterprises.

3. By setting the second sliding rheostat, the third sliding rheostat and the fourth sliding rheostat, in cooperation with the first sliding rheostat, the values of different current and voltage requirements can be adjusted to adapt to the different constant power requirements of electrode lifting, which is highly practical. .

4. Accumulators are set up in the oil return oil line and the oil injection oil line respectively. At the appropriate time, the energy in the system is converted into potential energy and stored. When the system needs it, the potential energy is converted into hydraulic energy and released. , resupply the system. When the system pressure increases instantaneously, it can absorb this part of energy to ensure that the pressure of the entire system is normal.

Description of the drawings

Figure 1 is a schematic structural diagram of a power constant system that can automatically adjust electrode positions according to the present invention.

In the figure, 1. Electrode, 2. Current transformer, 3. Isolation transformer, 4. First rectifier, 5. Second rectifier, 6. First sliding rheostat, 7. Three-position three-way servo valve, 8. Plunger Cylinder, 9. Second sliding rheostat, 10. Third sliding rheostat, 11. Fourth sliding rheostat, 12. First accumulator, 13. First safety valve, 14. Fuel tank, 15. Second accumulator, 16. Second safety valve, 17. Oil pump, 18. Liquid steel.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention and provides detailed implementation modes and specific operating procedures. However, the protection scope of the present invention is not limited to the following embodiments.

As shown in Figure 1, a power constant system that can automatically adjust the electrode position includes a current transformer 2 for detecting the current of the electrode 1, an isolation transformer 3 for detecting the voltage of the electrode 1, a first rectifier 4, and a second rectifier. 5. The first sliding rheostat 6, including the second sliding rheostat 9, the third sliding rheostat 10, the fourth sliding rheostat 11, the three-position three-way servo valve 7, the plunger cylinder 8, the oil return oil circuit and the oil injection oil circuit, current The transformer 2 is set on the connecting line of the electrode 1. The first rectifier 4 and the second rectifier 5 adopt a full-bridge rectifier circuit. The first output end of the current transformer 2 is connected to the sliding end of the second sliding rheostat 9 and the second The second end of the sliding varistor 9 and the first end of the third sliding varistor 10, and the second output end of the current transformer 2 are respectively connected to the first end of the second sliding varistor 9 and the second input end of the first rectifier 4. The sliding end and the second end of the two sliding varistor 9 are both connected to the first input end of the first rectifier 4, one end of the primary coil of the isolation transformer 3 is connected to the electrode 1, the other end of the primary coil of the isolation transformer 3 is grounded, and the other end of the primary coil of the isolation transformer 3 is grounded. One end of the secondary coil is connected to the first input end of the second rectifier 5, the other end of the secondary coil of the isolation transformer 3 is connected to the second input end of the second rectifier 5, and the first output end of the first rectifier 4 is connected to the second rectifier 5 respectively. The first output end and the sliding end of the first sliding rheostat 6, the second output end of the first rectifier 4 are respectively connected to the first end of the first sliding rheostat 6 and the first signal input end of the three-position three-way servo valve 7, The first end of the fourth sliding rheostat 11 is connected to the second output end of the second rectifier 5 and the second end of the first sliding rheostat 6 respectively. The sliding end and the second end of the fourth sliding rheostat 11 are both connected to the three-position three-way servo. The second signal input end of the valve 7 and the oil chamber of the plunger cylinder 8 are connected to the first interface of the three-position three-way servo valve 7. The driving end of the plunger cylinder 8 is connected to the electrode 1 through the cantilever. The second interface is connected to the oil return line, and the third interface of the three-position three-way servo valve 7 is connected to the oil filling line. The left position of the three-position three-way servo valve 7 conducts the oil chamber and the oil filling line of the plunger cylinder 8. The three-way servo valve 7 is non-conducting in the middle position, and the right position of the three-position three-way servo valve 7 conducts the oil chamber and return oil circuit of the plunger cylinder 8.

Among them, the return oil circuit includes a first accumulator 12 and a first safety valve 13. One end of the first accumulator 12 is connected to the second interface of the three-position three-way servo valve 7, and the other end of the first accumulator 12 One end of the first safety valve 13 is connected, and the other end of the first safety valve 13 is connected to the oil tank 14 . The oil filling circuit includes a second accumulator 15, a second safety valve 16 and an oil pump 17. One end of the second accumulator 15 is connected to the third interface of the three-position three-way servo valve 7 and the output end of the oil pump 17 respectively. The other end of the accumulator 15 is connected to one end of the second safety valve 16 , and the other end of the second safety valve 16 and the input end of the oil pump 17 are both connected to the oil tank 14 . The first accumulator 12 and the second accumulator 15 convert the energy in the system into potential energy at the appropriate time and store it. When the system needs it, they convert the potential energy into hydraulic energy and release it for resupply. When the pressure of the system increases instantaneously, it can absorb this part of the energy to ensure that the pressure of the entire system is normal.

The working method of the above-mentioned power constant system that can automatically adjust the electrode position includes the following steps:

S1: Adjust the sliding end position of the first sliding rheostat 6 so that when the electrode 1 current and the electrode 1 voltage are the required values, the voltage difference between the two ends of the first sliding rheostat 6 is zero. At this time, the three-position three-way servo valve 7 is in In the neutral position, electrode 1 does not move and maintains a balanced state with constant power;

S2: When the three-position three-way servo valve 7 detects that the first terminal voltage of the first sliding rheostat 6 is less than the second terminal voltage, the three-position three-way servo valve 7 switches to the right position. Under the action of the self-weight of the motor and plunger cylinder 8 Down, the liquid flow flows from the oil chamber of the plunger cylinder 8 into the return oil circuit through the three-position three-way servo valve 7, and the electrode 1 descends with the driving end of the plunger cylinder 8 until it returns to the equilibrium state;

When the three-position three-way servo valve 7 detects that the first terminal voltage of the first sliding rheostat 6 is greater than the second terminal voltage, the three-position three-way servo valve 7 switches to the left position, and the high-pressure liquid flows from the oil injection oil path through the three-position three-way The servo valve 7 flows into the oil chamber of the plunger cylinder 8, and the electrode 1 rises with the driving end of the plunger cylinder 8 until it returns to the equilibrium state.

Taking electric furnace steelmaking as an example, the working principle is as follows: the melting current and voltage are measured by the current transformer 2 and the isolation transformer 3 respectively. After rectification, the current terminal potential is reflected at the first end of the first sliding rheostat 6. The second end of a sliding rheostat 6 reflects the voltage terminal potential, and the three-position three-way servo valve 7 compares the two potentials.

When the current and voltage are at the required values, the voltage difference between the two ends of the first sliding rheostat 6 is zero, the working position of the three-position three-way servo valve 7 is in the neutral position, and the electrode 1 does not move.

Once the raw materials in the smelting furnace are melted, the liquid level of the molten steel 18 drops, and the smelting current decreases. At this time, the voltages output by the two sets of rectifiers are not equal, and the potentials at both ends of the first sliding rheostat 6 are not equal, and are output to the three-position three-way servo valve. The signal of 7 is a negative current, and the valve core moves to the left, causing the working position of the three-position three-way servo valve 7 to switch to the right position. Depending on the self-weight of electrode 1 and plunger cylinder 8, the liquid flows from plunger cylinder 8 through three The three-way servo valve 7 flows into the first accumulator 12 and the electrode 1 descends until it is rebalanced.

Once a molten pool is formed in the furnace, the scrap steel will hug the electrode 1 and form a short circuit when it collapses downward. At this time, the arc voltage is 0 and the current increases sharply. The potential of the current terminal on the first sliding varistor 6 rises, and the potential of the voltage terminal decreases. At this time, the signal sent to the three-position three-way servo valve 7 is a forward current, and the valve core moves to the right, causing the working position of the three-position three-way servo valve 7 to switch to the left position. The oil pump 17 works to form a high-pressure liquid flow. Flow flows from the second accumulator 15 into the plunger cylinder 8 and the electrode 1 is lifted upward until it is re-equilibrated.

Claims (5)

1. The utility model provides a but constant power system of automatically regulated electrode position, its characterized in that, including current transformer (2) that are used for detecting electrode current, be used for detecting electrode voltage's isolation transformer (3), first rectifier (4), second rectifier (5), first slide rheostat (6), three-position tee bend servo valve (7), plunger jar (8), oil return oil circuit and oiling oil circuit, the input of first rectifier (4) is connected to the output of current transformer (2), the input of second rectifier (5) is connected to the output of isolation transformer (3), the first output of first rectifier (4) is connected the first output of second rectifier (5) and the sliding end of first slide rheostat (6) respectively, the second output of first rectifier (4) is connected the first end of first slide rheostat (6) and the first signal input of three-position tee bend servo valve (7) respectively, the second output of second rectifier (5) is connected the first signal input of third end of three-position tee bend servo valve (7) respectively, the three-position servo valve (7) is connected to the three-position servo valve (8) the three-way interface (7), the third interface of the three-position three-way servo valve (7) is connected with an oil injection oil way, the left position of the three-position three-way servo valve (7) is communicated with an oil cavity of the plunger cylinder (8) and the oil injection oil way, the middle position of the three-position three-way servo valve (7) is not communicated, and the right position of the three-position three-way servo valve (7) is communicated with the oil cavity of the plunger cylinder (8) and the oil return oil way;

the working method of the power constant system capable of automatically adjusting the electrode position comprises the following steps:

s1: the sliding end position of the first slide rheostat (6) is adjusted, so that when the electrode current and the electrode voltage are required values, the voltage difference between the two ends of the first slide rheostat (6) is zero, at the moment, the three-position three-way servo valve (7) is positioned in the middle position, the position of the electrode (1) is not moved, and the balance state is maintained;

s2: when the three-position three-way servo valve (7) detects that the voltage of the first end of the first slide rheostat (6) is smaller than the voltage of the second end, the three-position three-way servo valve (7) is switched to the right position, liquid flow flows from an oil cavity of the plunger cylinder (8) into an oil return oil way through the three-position three-way servo valve (7) under the action of the dead weight of the motor and the plunger cylinder (8), and the electrode (1) descends along with the driving end of the plunger cylinder (8) until the state returns to the equilibrium state again;

when the three-position three-way servo valve (7) detects that the voltage of the first end of the first slide rheostat (6) is larger than the voltage of the second end, the three-position three-way servo valve (7) is switched to the left position, high-pressure liquid flow flows into an oil cavity of the plunger cylinder (8) from an oil injection oil way through the three-position three-way servo valve (7), and the electrode (1) rises along with the driving end of the plunger cylinder (8) until the plunger cylinder returns to the balanced state again.

2. The power constant system capable of automatically adjusting the electrode position according to claim 1, further comprising a second sliding rheostat (9) and a third sliding rheostat (10), wherein the first output end of the current transformer (2) is respectively connected with the sliding end of the second sliding rheostat (9), the second end of the second sliding rheostat (9) and the first end of the third sliding rheostat (10), the second output end of the current transformer (2) is respectively connected with the first end of the second sliding rheostat (9) and the second input end of the first rectifier (4), and the sliding end and the second end of the second sliding rheostat (9) are respectively connected with the first input end of the first rectifier (4).

3. The power constant system capable of automatically adjusting the electrode position according to claim 1, further comprising a fourth slide rheostat (11), wherein a first end of the fourth slide rheostat (11) is respectively connected with a second output end of the second rectifier (5) and a second end of the first slide rheostat (6), and a sliding end and a second end of the fourth slide rheostat (11) are respectively connected with a second signal input end of the three-position three-way servo valve (7).

4. The power constant system capable of automatically adjusting the electrode position according to claim 1, wherein the oil return path comprises a first energy accumulator (12) and a first safety valve (13), one end of the first energy accumulator (12) is connected with a second interface of the three-position three-way servo valve (7), the other end of the first energy accumulator (12) is connected with one end of the first safety valve (13), and the other end of the first safety valve (13) is connected with an oil tank (14).

5. The power constant system capable of automatically adjusting the electrode position according to claim 1, wherein the oiling oil way comprises a second energy accumulator (15), a second safety valve (16) and an oil pump (17), one end of the second energy accumulator (15) is respectively connected with a third interface of the three-position three-way servo valve (7) and an output end of the oil pump (17), the other end of the second energy accumulator (15) is connected with one end of the second safety valve (16), and the other end of the second safety valve (16) and an input end of the oil pump (17) are both connected with an oil tank (14).