KR200333550Y1 - Apparatus for controlling steam pressure in vod - Google Patents

Abstract

The present invention is a vacuum equipment to control the steam supply pressure by comparing the set value which is variable set according to the temperature and pressure of the steam in the equipment for forming a vacuum for manufacturing high value-added steel to perform the blow It relates to a steam pressure control device of the.

To this end, the present invention detects the steam pressure discharged to the ejector, compares it with the pressure set value input by the driver, and controls the steam discharge pressure by adjusting the opening amount of the steam pressure control valve according to the difference, thereby vacuuming the vacuum vessel. A steam pressure control device of a vacuum facility configured to maintain a constant temperature, the steam pressure control unit detecting a steam supply pressure supplied to the steam pressure control valve, a steam temperature detection unit detecting a supplied steam temperature, and a steam pressure A valve driving unit for controlling the driving of a control valve, a steam injection pressure detection unit detecting a pressure of steam injected into the ejector, and a pressure setting value varied according to the steam supply pressure and steam temperature, and compared with the injection pressure detection value. Steam pressure control unit for outputting a valve opening amount control signal to the valve drive unit according to the difference It characterized by comprising a.

Description

{APPARATUS FOR CONTROLLING STEAM PRESSURE IN VOD}

The present invention relates to a steam pressure control device of a vacuum installation, and more particularly, in accordance with the detection value of the steam supply pressure and the temperature and pressure of steam in equipment for forming a vacuum to produce a high value-added steel The present invention relates to a steam pressure control device of a vacuum installation configured to control a steam supply pressure by comparing a set value which is set variable.

1 is a system configuration diagram showing a schematic configuration of a conventional vacuum equipment. As shown in FIG. 1, in a vacuum facility such as a vacuum decarburization device (VOD), which is a facility for making a vacuum by performing vacuum for manufacturing high value-added steel, a high-temperature steam is injected into the ejector 7 and a condenser 10 is provided. By rapidly cooling the steam with the cooling water supplied to the inside of the vacuum vessel (9) to vacuum to refine the molten steel contained in the ladle (8).

At this time, the degree of vacuum varies depending on the temperature of the steam injected into the ejector 7 and the temperature of the cooling water. In order to make the inside of the vacuum vessel 9 to a desired vacuum state, the state of steam is most important. Such steam shows the best performance in a saturated steam state that does not contain moisture, and the saturated steam refers to a gaseous steam that does not contain water, and is changed by steam temperature and pressure. In other words, at 1 kgf / cm2 as absolute temperature, water becomes saturated at 100 ° C and becomes steam, but when the pressure of steam is increased, the saturation temperature of water also increases.

FIG. 2 is a block diagram illustrating a method for controlling a steam pressure of a conventional vacuum equipment. As shown in FIG. 2, a driver for detecting a steam supply pressure to detect a steam supply pressure to make a desired vacuum state inside a vacuum vessel 9 in a conventional vacuum system is shown in FIG. In the vacuum facility by detecting the deviation compared to the pressure set value inputted by the controller and keeping the steam pressure supplied to the ejector 7 by adjusting the opening amount of the steam pressure control valve 4 to compensate the detected deviation. Ensure maximum performance.

However, in such a conventional vacuum system, steam is supplied to the vacuum equipment through a pipe. Even if a thermostat is installed to prevent the temperature drop of steam, the temperature is decreased due to the temperature drop and the time delay due to the distance to the vacuum equipment. Various factors, such as lower than the initial steam temperature, or high temperature depending on the operating conditions of other equipment.

Therefore, when the driver inputs the pressure setpoint as 8 kgf / cm2 considering the steam temperature at the steam supply stage as an example of 170 ° C, the steam temperature detected at the outlet of the steam pressure control valve 4 actually drops to about 165 ° C and is supplied. Or it can be supplied elevated to about 175 ℃. In this case, however, the pressure setpoint is initially fixed at 8 kgf / cm2, which is an input value set by the driver, so that the pressure setpoint cannot be changed appropriately according to the temperature change of the steam, so that the vacuum state inside the vacuum vessel 9 can be optimally maintained. There was a problem that could not be. In addition, there was a problem of the efficiency decrease in the vacuum system accordingly.

Therefore, the present invention has been devised to solve the above-mentioned conventional problems, and its purpose is to change the pressure setpoint according to the temperature change in the steam supply line, so that the vacuum state inside the vacuum vessel according to the steam temperature and the pressure change is desired. It is an object of the present invention to provide a steam pressure control device for a vacuum system that can be kept constant at all times to improve system performance.

1 is a system diagram showing a schematic configuration of a conventional vacuum installation.

2 is a block diagram showing a schematic configuration of a steam pressure control apparatus of a conventional vacuum installation.

3 is a block diagram showing a schematic configuration of a steam pressure control device of a vacuum installation according to the present invention.

4 is a circuit diagram showing a detailed configuration of the steam pressure control unit according to the present invention.

Explanation of symbols on the main parts of the drawings

3 ... valve actuator, 4 ... steam pressure control valve,

7 ejector, 8 ladle,

9 ... vacuum vessel, 10 ... condenser,

20 ... steam pressure control, 21 ... saturated steam database,

22 ... pressure comparison part, 22-1 ... supply pressure comparison part,

22-2 ... Compare set pressure, 23 ... Discharge pressure control,

24 ... operator setting input section, 30 ... supply pressure detection section,

40.Supply temperature detector.

In order to achieve the above object, the steam pressure control device of the vacuum installation according to the present invention detects the steam pressure discharged to the ejector and compares it with the pressure set value input by the driver, and according to the difference, the opening amount of the steam pressure control valve. In the steam pressure control device of a vacuum installation to maintain a constant vacuum state of the vacuum vessel by controlling the steam discharge pressure by adjusting the

A steam supply pressure detector for detecting a steam supply pressure supplied to the steam pressure control valve, a steam temperature detector for detecting a supplied steam temperature, a valve driver for controlling a driving of a steam pressure control valve, and a sprayed in the ejector Steam injection pressure detection unit for detecting the pressure of the steam, and the steam setting pressure variable according to the steam supply pressure and steam temperature is compared with the injection pressure detection value and outputs the valve opening amount control signal to the valve drive unit according to the difference It is characterized by comprising a pressure control unit.

Hereinafter will be described in detail with reference to the accompanying drawings the configuration and effect of the steam pressure control device of a vacuum installation according to a preferred embodiment of the present invention.

3 is a block diagram showing a schematic configuration of a steam pressure control device of a vacuum installation according to the present invention. As shown in Figure 3, the steam pressure control device of the vacuum installation according to the present invention is the steam supply pressure detection unit 30 for detecting the steam supply pressure supplied to the steam pressure control valve through the piping line, the steam temperature supplied A temperature detector 40 for detecting the pressure, a valve driver 3 for controlling the driving of the steam pressure control valve 4, a steam discharge pressure detector 5 for detecting the pressure of steam injected into the ejector 7, From the steam pressure control unit 20 and the driver to vary the pressure set value according to the steam supply pressure and the steam temperature and output the valve opening amount control signal to the valve driving unit 3 according to the difference compared to the discharge pressure detection value. And a process computer 1 which receives the pressure set value and outputs it to the steam pressure controller 20.

In this configuration, the steam pressure control unit 20 receives the signal detected by the steam temperature detection unit 40, the saturation pressure database 21 for selecting and outputting the saturation pressure according to each detected temperature, and the Supply pressure comparison unit 22-1 for comparing the saturation pressure and the steam supply pressure detection value according to the detected temperature output from the database 21 and the set pressure comparison unit 22 for comparing the steam supply pressure and the driver set pressure value. -2) compares the final control pressure output from the pressure comparison unit 22 with the steam discharge pressure detected by the steam discharge pressure detection unit 5 and compares the final pressure with the pressure difference. The discharge pressure control part 23 which judges a valve opening amount and outputs a control signal to the valve drive part 3 is provided.

4 is a circuit diagram showing a detailed configuration of the steam pressure control unit according to the present invention. As shown in FIG. 4, the steam pressure controller for implementing the present invention includes an AND gate 24-a for performing an AND operation on the operation signal of the vacuum start signal input from the process computer 1 and the driver input set value input signal. A driver signal input section 24 having a transistor TR1 for driving the first relay R1 that is turned on / off in accordance with the output of the gate 24-a and connected to the emitter stage thereof is provided.

In addition, the supply pressure comparing unit 22-1 is based on the temperature reference saturation pressure table shown in Table 1 by the saturation steam database 21 according to the steam supply pressure detected by the supply pressure detecting unit 30 and the detected temperature. A second comparator AMP1 for comparing the selected and output pressure set values and a second transistor connected to the emitter stages of the transistors TR3 and TR3 that are turned on / off according to the comparison result of the first comparator AMP1; The relay R2 is provided. In this case, Table 1 is a temperature-based saturation steam table stored in the saturation steam database.

The set pressure comparing unit 22-2 includes a second comparator AMP2 for comparing a steam supply pressure or a temperature reference pressure set value selectively input by the relay switch SW2 with a pressure set value set by the driver, and a second comparator AMP2. The transistor TR4 receives the output signal of the second comparator AMP2 as a base drive signal, and has a third relay R3 connected to the emitter terminal of the transistor TR4.

Temperature (℃) Saturation pressure kg / ㎠ mmHg 110 1.4609 1074.6 120 2.0245 1489.1 130 2.7544 2026.0 140 3.6848 2710.4 150 4.8535 3570.0 160 6.3021 4635.6 170 8.0759 5940.3 175 9.1000 6693.6 180 10.224 7520.3 184 11.455 8425.8 190 12.799 9414.4 195 14.263 10491.2 200 15.856 11663.0 205 17.584 12394.0 210 19.456 14311.0 215 21.479 15799.0 220 23.660 17403.3

Hereinafter will be described the operation and effect of the steam pressure control device of the vacuum installation according to the present invention.

As shown in Figure 4, the steam pressure control apparatus of the vacuum installation according to the present invention, first, when the driver inputs the driving start command of the vacuum installation through the process computer 1, and enters the pressure set value transistor (TR1) ) Is operated to operate the first relay R1.

On the other hand, the steam temperature detected by the temperature detection unit 40 provided on the input end side of the steam pressure control valve 4 is input to the database 21 through the transistor TR2, and in this case, the temperature reference saturated steam in the database 21. The saturation pressure corresponding to the input steam temperature is searched for in the table, and the saturation pressure value relative to the temperature is output to the first comparator AMP1 of the supply pressure comparator 22-1. At this time, the steam supply pressure detection value detected from the steam supply pressure detector 30 is input to the type force terminal of the first comparator AMP1 of the supply pressure comparator 22-1.

The first comparator AMP1 outputs a result of comparing the two pressure values to turn on and off the transistor TR3. If the steam supply pressure is greater than the saturation pressure with respect to the temperature, a low signal is output so that the transistor TR3 is turned off and thus the second relay R2 is turned off. On the other hand, when the steam supply pressure is smaller than the saturation pressure to the temperature, that is, when the temperature of the steam is high, a high signal is output to turn on the transistor TR3 and the second relay R2.

At this time, when the second relay R2 is turned off, the steam supply pressure detection value is input to the second comparator AMP2 of the set pressure comparing unit 22-2 through the b contact of the relay switch SW2, and the second When the relay R2 is turned on, the saturated pressure value with respect to temperature is input to the second comparator AMP2 of the set pressure comparator 22-2.

At one input end of the second comparator AMP2 of the set pressure comparator 22-2, the steam supply pressure value or the temperature saturation is achieved through the relay switch SW2 according to the comparison result of the supply pressure comparator 22-1. The pressure value is input, and the operator pressure set value is input to the type force stage. Accordingly, the second comparator AMP2 compares the input signal and turns on / off driving of the transistor TR4 and the third relay R3 provided at the output terminal according to the comparison result. For example, when a steam supply pressure value (or a saturation pressure value relative to temperature) is input to the one input terminal of the second comparator AMP2, the steam supply pressure value is compared with an operator pressure set value which is a type force signal, and the steam supply pressure value is an operator set pressure value. If larger, a low level signal is output to turn off the transistor TR4 so that the relay R3 is turned off. The steam supply pressure (or saturation pressure value versus temperature) becomes the final pressure set value through the contact b of the relay switch SW3 and is input to the discharge pressure controller 23.

On the other hand, when the driver pressure set value is greater than the steam supply pressure value (or the saturated pressure value relative to the temperature), the second comparator AMP2 outputs a high level signal to operate the transistor TR4 and the third relay RY3. Let's do it. As a result, the relay switch SW3 is switched to the contact a so that the driver pressure setting value is input as the final pressure setting value of the discharge pressure control unit 23.

As another example, when the driver set pressure value is not input at the start of the operation of the vacuum installation, the transistor TR1 is turned off and the first relay R1 is turned off, so that the contact point of the relay switch SW1 is at the b contact point. Since the pressure set value input to the discharge pressure control unit 23 is maintained according to the comparison result of the supply pressure comparison unit 22-2 regardless of the comparison result of the set pressure comparison unit 22-2, the relay switch ( It is determined by the signal output through SW3).

When the final pressure set value is input to the discharge pressure control unit 23 as described above, the discharge pressure control unit 23 calculates the difference between the steam discharge pressure value detected by the steam discharge pressure detection unit 5 and the final pressure set value. In order to compensate the difference, the control signal is output to the valve driving unit 3 to adjust the opening degree of the valve so that the pressure of the steam injected into the ejector 7 becomes the saturation pressure according to the steam temperature. As a result, the steam injected into the ejector 7 becomes saturated steam, thereby maintaining the inside of the vacuum vessel 9 in a desired vacuum state.

Steam pressure control apparatus of the vacuum installation according to the present invention is not limited to the above-described embodiment can be implemented in various modifications within the range allowed by the technical idea of the present invention.

As described above, the steam pressure control device of the vacuum installation according to the present invention detects the steam temperature supplied to the steam pressure control valve, calculates the steam saturation pressure based on the steam temperature, compare with the steam supply pressure, and compare Depending on the result, the pressure setpoint can be varied to keep the steam saturated.

Therefore, by maintaining the pressure of the steam injected into the ejector at a saturation pressure, the inside of the vacuum vessel can be always maintained in a constant vacuum state, and thus there is an effect of obtaining the maximum performance in refining molten steel in the ladle. Furthermore, by maintaining the vacuum state at the optimum state, the effect can be expected to improve the quality of the special steel produced.

Claims (3)

By detecting the steam pressure discharged to the ejector and comparing it with the pressure set value input by the driver, and controlling the steam discharge pressure by adjusting the opening amount of the steam pressure control valve according to the difference to maintain the vacuum state of the vacuum vessel constant In the steam pressure control device of the installed vacuum equipment, A steam supply pressure detector detecting a steam supply pressure supplied to the steam pressure control valve; A steam temperature detector for detecting a steam temperature to be supplied; A valve driver for controlling driving of the steam pressure control valve; A steam injection pressure detector detecting a pressure of steam injected into the ejector; And a steam pressure controller configured to vary a pressure set value according to the steam supply pressure and steam temperature, and output a valve opening amount control signal to the valve driving unit according to the difference compared to the injection pressure detection value. Steam pressure control device. The method of claim 1, wherein the steam pressure control unit A saturation pressure database that receives the signal detected by the steam temperature detector and selects and outputs a saturated steam pressure according to each detected temperature; A pressure comparator comprising a supply pressure comparator for comparing the saturation pressure and the steam supply pressure detected value according to the detected temperature output from the database, and a set pressure comparator for comparing the steam supply pressure and the driver set pressure value; A discharge pressure control unit for comparing the final control pressure output from the pressure comparison unit with the steam discharge pressure detected by the steam discharge pressure detection unit to determine the valve opening amount according to the pressure difference, and outputting a control signal to the valve driving unit; Steam pressure control device for a vacuum installation, characterized in that provided. The method of claim 2, The pressure comparing unit may include a second relay configured to input a smaller pressure value to the set pressure comparing unit as a result of comparing the saturated steam pressure output from the steam saturation pressure database with the steam supply pressure; And a third relay configured to compare the pressure value input through the second relay with the pressure set value input from the driver, and output a larger pressure value to the discharge pressure controller as a result of the comparison. Steam pressure control.