KR20040013954A - Emergency Control Device for regulating the control valve feeding the gases to smelting furnace - Google Patents

Abstract

PURPOSE: An emergency control system of control valve for supplying gas into refining furnace is provided to prevent erosion of gas injection nozzle due to misoperation of the control valve and quality deterioration and accidents generated due to outflow of molten iron and prevent quality deterioration of high value added stainless steel. CONSTITUTION: In a refining furnace comprising a control valve(100) for supplying gas into the refining furnace through a nozzle having nozzle inner pipe and nozzle outer pipe, the emergency control system of the control valve for supplying gas into the refining furnace comprises a moisture detecting sensor(202) for detecting content values of moisture contained in air supplied to an electropneumatic positioner(10) to control opening degree of the control valve(100); a control part(300) for cutting off power supply of the electric motor operated valves(205,205') and giving an alarm if moisture content values detected in the moisture detecting sensor(202) exceed a moisture upper limit value; a pair of electric motor operated valves(205,205') installed to block compressed air supplied to the electropneumatic positioner(10) by controlling of the control part(300); a filling machine(208) for supplying emergency compressed air to the electropneumatic positioner(10) during blocking of air supplied to the electropneumatic positioner(10); a pressure switch(209) for detecting a pressure lower limit value of the filling machine(208); and an electric motor operated valve(204) operated by the pressure switch(209) during detection of the pressure lower limit value of the filling machine(208) to block pressure converted air supplied to the control valve(100) by the electropneumatic positioner(10).

Description

Emergency control device for regulating the control valve feeding the gases to smelting furnace}

The present invention relates to an emergency control device for a control valve for supplying gas to a refining furnace used in a stainless steelmaking process, and more specifically, the electric positioner for controlling the opening of the control valve for controlling the amount of gas supplied to the refining furnace is compressed air. The present invention relates to an emergency control device for a control valve for supplying gas to a refining furnace that can prevent accidents and deterioration due to erosion of the gas injection nozzle and leakage of molten metal caused by malfunctions.

1 is a schematic configuration of a nozzle for injecting gas into a smelting furnace 13 and a smelting furnace 13 conventionally used, exteriors 14 and 15, and a facility for detecting and controlling a flow rate supplied to the nozzle. It is also. In the drawing, a solid line means a pipe through which a fluid passes, and a dotted line (except inside and outside) means an electric wire which is a passage of an electric signal.

In the refining furnace 13 used in the stainless steelmaking process, a molten steel product is produced by blowing a specific gas through a nozzle composed of internal and external parts 14 and 15 attached to the lower part. In order to stir the molten metal contained in the refining furnace 13 in the production process, oxygen and inert gas nitrogen or argon are blown through the nozzle inner tube 14 to prevent erosion of the nozzle inner tube 14 by the molten metal. Nitrogen or argon and compressed air are blown through the nozzle shell 15. Molten steel is produced by the oxidized and reduced dehydration step by the blown gases.

Adjustment of the gas supply amount supplied to the refining furnace 13 is performed through the following process. The flow rate detected through the flow rate detector 12 in the pipe through which the gas is passed is input to the controller 11 after being converted into a corresponding electric signal. In the controller 11, when the flow rate measurement signal is input, the flow rate supply control signal for inputting a flow rate control signal for moving the flow rate by the set value set in the controller 11 is input to the electro-positioner 10. The electric positioner 10 converts an electrical signal into a corresponding air pressure to output air pressure for operating the control valve 100 to control the flow rate by adjusting the opening degree of the control valve 100.

In order to provide the air pressure for operating the control valve 100, the air positioner 10 is supplied with air from a separate compressed air source 18, which is shown in FIG. When the opening degree of the control valve 100 is controlled to change the flow rate, the amount of gas blown through the nozzle inner tube 14 and the nozzle outer tube 15 is changed accordingly. The flow rate is controlled independently of the nozzle inner tube 14 and the nozzle outer tube 15.

The operation of the electric positioner 10 and the control valve 100 will be described with reference to FIG. 2 as follows.

The electric positioner 10 converts an operation signal of the control valve 100 into a corresponding pneumatic pressure using an electric signal (electric signal changed in the range of 4-20 mA) output from the controller 11. In other words, by using the compressed air of 4 ~ 6kg / cm ² supplied from the compressed air source 18, in accordance with the electrical signal output from the controller 11 is converted into a pressure of 1.2 ~ 2.0kg / cm 2 control valve ( 100). Control valve 100 is a spindle connected to the diaphragm 101 through the tension and contraction action of the diaphragm 101 and the spring 102 connected to the diaphragm 101 can store the air for the control valve operation Up and down movement of (104) to adjust the opening degree corresponding to 0 ~ 100% to a pressure of 1.2 ~ 2.0kg / cm ² . The display of the opening degree as described above is confirmed through the opening indicator 103 installed in the control valve 100.

In order to control the opening degree of the control valve 100 through the above-described electrophoretic conversion, the compressed air source 18 and the filter 19 which filters the moisture and dust of the compressed air source 18 are the front end of the electric positioner 10. Is provided.

However, the compressed air source 18 compresses and provides air in the atmosphere. At this time, moisture and dust (dust) included in the atmosphere are also included. When the moisture contained in this way is not completely removed by the filter 19 which filters the dust and water, and the moisture is penetrated into the pore positioner 10, the air passage of the pore positioner 10 composed of fine nozzles is blocked and thus from the compressed air source 18. It will not be supplied with air. Accordingly, the operation of the electro-positioner 10 is stopped and the operation of the control valve 100 is also stopped at the same time. In addition, even when the compressor of the compressed air source 18 accidentally fails and the air supply is stopped, the operation of the control valve is also stopped.

When the operation of the control valve 100 is stopped as described above, the opening degree of the control valve 100 is completely closed according to the operating situation, and the flow rate is blocked or opened to supply the flow rate over the set value. Therefore, when the control valve 100 is completely closed, the gas supplied to the nozzles 14 and 15 of the refining furnace 13 is cut off, so that the inside of the nozzles and the outside of the nozzles are dissolved by the molten metal contained in the refining furnace 13. (14, 15) was eroded, the nozzle was eroded and disappeared, there was a problem that the melt flows out through the hole (hole) in which the nozzle was mounted, leading to a large accident. In addition, when the control valve 100 is completely opened, there is a problem in that a large amount of gas flow rate than the set value is supplied, which significantly affects the quality of the high value added stainless steel.

Furthermore, when the melt flows out due to nozzle erosion, the molten metal is eroded up to the fireproof wall 16 of the refining furnace 13. This assumes that the heat resistance of the refining furnace 13 is increased, thereby increasing the cost according to the manufacturing.

The present invention has been made to solve the above problems, an object of the present invention is to provide a gas position in the refining furnace is malfunctioning due to the moisture contained in the compressed air of the electric positioner for opening the control valve for controlling the amount of gas supplied to the refining furnace The present invention provides an emergency control device for a control valve that supplies gas to a refining furnace that can prevent quality deterioration and accidents caused by erosion of the injection nozzle and leakage of molten metal.

Another object of the present invention is to provide an emergency control device for a control valve for supplying gas to a refining furnace that can prevent the quality degradation of high value-added stainless steel to solve consumer complaints.

1 is a schematic configuration diagram of a conventional refining furnace equipment,

2 is a block diagram of a conventional control valve and a major positioner,

3 is an installation state of the emergency control apparatus according to the present invention,

4 is a detailed configuration diagram of the emergency control apparatus according to the present invention;

5 is a detailed circuit diagram of the controller of FIG. 4;

6 is a normal operation state of the emergency control apparatus according to the present invention,

Figure 7 is an operating state of the emergency control device at the pressure drop of the filling machine.

※ Explanation of symbols about main part of drawing ※

10: Major Positioner 11: Controller

12: flow detector 13: refining furnace

14: nozzle inner tube 15: nozzle outer tube

16: fireproof wall 18: compressed air source

19: Filter 100: Control valve

101: diaphragm 102: spring

103: open door 104: spindle

105: body 200: emergency control device

201: Mounting filter 202: Moisture detection sensor

204: electric side 205,205 ': electric side

206: (cab) alarm device 208: filling machine

209: pressure switch 210: contact

211,211 ', 211 ", 211'": Coupler 213: Power supply terminal

214: output terminal 300: control unit

301, 302 relay 303 variable resistor

304: amplifier 305: signal inversion

306: amplifier 308: transistor

309: relay 310: constant voltage portion

Emergency control device for a control valve for supplying gas to the refinery of the present invention for achieving the above object, the water detection sensor for detecting the water content contained in the air supplied to the positioner for controlling the opening of the control valve; A controller for generating a power cut-off and an alarm of the electric valve when the moisture content detected by the moisture detection sensor exceeds an upper limit of moisture; A pair of electric valves installed to block the compressed air supplied to the electric positioner under the control of the controller; A filler for supplying emergency compressed air to the major positioner when the air is supplied to the major positioner; A pressure switch for detecting a lower pressure limit of the filler; And an electric valve operated by a pressure switch to detect a pressure lower limit of the filler to block the pressure-converted air supplied to the control valve by the electric positioner.

Hereinafter, an emergency control apparatus of a control valve for supplying gas to a refinery of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic diagram illustrating a gas supply unit in which an emergency control device for a control valve for supplying gas to a refining furnace according to the present invention is installed, and the air compressed in the conventional positioner 10 and the positioner 10 is provided. An emergency control device 200 according to the present invention is inserted between the compressed air sources 18 to be supplied.

The emergency control apparatus 200 detects moisture contained in the air supplied from the compressed air source 18, and is operated when the detected moisture content exceeds the upper limit of the moisture to be supplied for adjusting the opening degree of the control valve 100. The air is supplied with air whose moisture does not exceed the upper moisture limit. At this time, the electrical signal input from the controller 12 for outputting the adjustment signal according to the flow rate detection is connected as in the prior art. Emergency control device 200 is also preferably manufactured to be mounted in a stand type for the convenience of installation. It also works when no air is supplied from the compressed air source 18.

As the emergency control apparatus 200 is installed as described above, the air supplied from the compressed air source 18 is not directly supplied from the electric positioner 10 to the control valve 100, and thus the emergency control apparatus 200 of the present invention is provided. Supplied through. In the figure, the part shown with a solid line is a pipe to which air is supplied, and the part shown with a dotted line is an electric wire.

4 shows a detailed structure of the emergency control apparatus 200 of the present invention.

Emergency control apparatus 200, as shown, for detecting the opening degree of the control valve 100, the moisture detection sensor 202 for detecting the moisture content contained in the air supplied to the electro-positioner 10; A control unit 300 for generating a power cut-off and an alarm of the electric valves 205 and 205 'when the water content detected by the water detection sensor 202 exceeds an upper limit of water; A pair of electric valves 205 and 205 'installed to block compressed air supplied to the electro-positioner 10 under the control of the controller 300; A filler 208 for supplying emergency compressed air to the positioner 10 when the air is supplied to the positioner 10; A pressure switch 209 for detecting a lower pressure limit of the filler 208; And an electric valve 204 which is operated by the pressure switch 209 when detecting the lower pressure limit of the filler 208 to block the pressure-converted air supplied to the control valve 100 by the electric positioner 10. Include.

The moisture detection sensor 202 detects the moisture content contained in the air supplied from the compressed air source 18. Although not illustrated, the moisture detection sensor 202 has an output converter which converts the detected moisture content into an analog signal and outputs the analog signal. The analog converted detection signal is input to the controller 300. A pipe (shown in solid line) extending from the compressed air source 18 is connected to the emergency control device 200 by a coupler 211. Coupler 211 is used to connect the pipes to keep them airtight.

The water detection sensor 202 is fixed by the mounting filter 201, and compressed air is supplied to the transmission valve 205 via the mounting filter 201. The transmission side 205 is directly connected to another transmission side 205 ', and a filter 19 is inserted therebetween. The filter 19 is for removing moisture and dust. The electric valves 205 and 205 'are main air sources for supplying compressed air to the electric positioner 10 to operate the control valve 100 from the compressed air source 18. The supplied air pressure is 4 to 6 kg / cm ² .

The other end of the electric side 205 ′ connected to the rear end is connected to the coupler 211 ′ through a pipe, and a pipe communicating with the filler 208 is connected to the middle of the pipe. Therefore, the motor side 205 'is in communication with both the coupler 211' and the filler 208. The coupler 211 ′ is connected to the electro-positioner 10 through a pipe in a conventional air supply method.

Referring again to the drawings, the air discharged from the electro-positioner 10 is not supplied directly to the control valve 100 is supplied to the coupler (211 ") of the emergency control device 200 and then another electric valve 204 It is supplied to the control valve 100 through a coupler 211 '″ connected by a pipe.

The control unit 300 constantly detects the concentration of water using a detection signal input from the water detection sensor 202, and compares the detected water content value with the water upper limit value when the water content value is higher than a preset water upper limit value. The control signal is outputted to the electric power cutoff of the electric sides 205 and 205 'and the cab alarm device 206. Power applied to the electric valves 205 and 205 'is supplied through the power supply terminal 213, and a control signal to the alarm device 206 is transmitted through the output terminal 214.

The electric valves 205 and 205 'are turned on / off by a signal output from the controller 300, and when the electric valves 205 and 205' are turned off, the control is continued by the clean air compressed in the filling machine 208. . When the electric valves 205 and 205 'are blocked, the compressed air stored in the filling machine 208 is supplied to the electric positioner 10 through the coupler 211' through a pipe connected thereto, and then discharged after being converted to an appropriate pressure. do. The discharged compressed air passes through the electric valve 204 through the coupler 211 ", is supplied to the control valve 100 through the coupler 211 '", and the opening degree control of the control valve 100 is performed. At this time, the electric positioner 10 changes the pressure in accordance with the control signal input from the control system 11 as in the prior art.

When the pressure of the clean compressed air stored in the filling machine 208 is lowered, the reduced pressure state is detected by the pressure switch 209. If the detected pressure value reaches the set lower limit value, the switch 209 is operated to block the electric valve 204 to maintain the control state up to the present. Reference numeral 210 is a contact point.

5 is a detailed circuit diagram of an embodiment of the control unit 300 of the emergency control apparatus 200 of the present invention. A relay 301 having a normally closed contact state and supplying power input through the power supply terminal 213 to the electric valves 205 and 205 ', and having an always open contact state to transmit an alarm signal to the alarm device 206. A relay 302, a constant voltage unit 310 for rectifying and outputting power input through the power supply terminal 213, and a detection signal input from the moisture detection sensor 202 is connected to the negative terminal. An amplifier 304 having a variable resistor 303 for setting an upper limit of moisture, a signal inverter 305 for inverting the polarity of a signal input from the amplifier 304, and the signal; An amplifier 306 for amplifying the signal output from the inverter 305, a transistor 308 for receiving the signal output from the amplifier 306, and a collector of the transistor 308, the water content is Smaller than the upper water limit It is consists of a relay 309 for switching the contact point of the relay 301 and 302.

The operating state of the control unit 300 having the above configuration is as follows.

An analog signal corresponding to the moisture content detected from the moisture detection sensor 202 is input through the negative terminal of the amplifier 304. When the moisture content detection signal is input, the amplifier 304 is set via the variable resistor 303 and compared with the upper limit of moisture input through the (+) terminal. As a result of the comparison, if the detected moisture content is higher than the upper limit, a negative value is output from the amplifier 304. The output negative value is input to the amplifier 306 after being inverted to the positive signal value by the signal inverter 305. After being amplified by the amplifier 306, the output value is input to the base of the transistor 308.

The transistor 308 is connected to a power supply control relay 309 of the motor side 205 and 205 '. When a voltage is applied to the base of the transistor 308, the relay 309 is activated to change the contact state of the relays 301 and 302. The relay 301 is always changed from the closed contact state to the open contact state, so that the electric valves 205 and 205 'are switched to the flow path blocking state (off). In addition, the relay 302 is always changed from the open contact state to the closed contact state, while the power supplied through the power connection terminal 213 is connected to the alarm device 206 through the output terminal 214, the moisture content is Notify the administrator that the upper limit is exceeded. The constant voltage unit 310 is for supplying a DC power supply (+ 15V, + 5V, etc.).

6 and 7 are for showing the operating state of the emergency control device 200 as described above, and the operating state of the filler pressure drop when the steady state and the water content exceeds the upper limit of the water, respectively.

In the normal operating state, as shown in FIG. 6, the compressed air supplied from the compressed air source 18 is coupled to the coupler 211, the mounting filter 201, the electric valve 205, the filter 19, the electric valve 205 '. It is supplied through The other end of the electric valve 205 'is connected to the coupler 211' connected to the outside to supply compressed air to the electro-positioner 10.

The pressure of the compressed air is changed in the electric positioner 10, and the air whose pressure is changed is blown back into the control valve 100 via the electric valve 204 and the coupler 211 ′ ″ through the coupler 211 ″. . The electric positioner 10 is operated according to the electric signal input from the control system 12 as in the prior art. In the above, the electric valves 204, 205, and 205 'all have fluid flow passages open (on operation), and compressed air passes therethrough.

If the water content detected from the water detection sensor 202 exceeds the set water upper limit in the compressed air supply state as described above, the control unit 300 turns off the electric valves 205 and 205 'to be supplied from the compressed air source 18. Shut off the air. When the supply of compressed air is cut off, the air compressed and stored in the filler 208 is supplied to the electro-positioner 10 through the coupler 211 ′. The air pressure supplied at this time is similar to the air pressure supplied from the compressed air source 18. Also, the electric side 204 is not blocked.

The air supplied to the electro-positioner 10 through the coupler 211 'flows back into the coupler 211 "after the pressure is changed by the electro-positioner 10, and the electric valve 204 and the coupler 211'". Passed through and is input to the control valve (100).

Compressed air is supplied from the filler 208 to the pore positioner 10, but since the supply of new compressed air is stopped, the air pressure of the filler 208 decreases with time. The pressure switch 209 detects the air pressure of the filling machine 208 and operates the electric valve 204 to block air movement when the pressure lower limit is reached.

Therefore, as shown in FIG. 7, the compressed air filled in the filling machine 208 is slightly left in the lower side, and the control state of the control valve 100 maintains the current state. During this state maintenance time, the maintenance panel is dispatched to repair the defect of the compressed air source 18 so that the control valve 100 can be quickly restarted.

According to the present invention as described above, the deterioration of the quality due to the erosion of the gas injection nozzle and the leakage of the melt due to the malfunction of the control valve generated by the moisture contained in the compressed air for controlling the control valve for controlling the gas supply to the refinery Accidents can be prevented in advance, and the customer's complaints can be resolved by preventing the quality deterioration of high value-added stainless steel.

Claims (4)

In a refining furnace (13) provided with a control valve (100) for supplying gas into a refining furnace through a nozzle having a nozzle inner tube (14) and a nozzle outer tube (15), A water detection sensor 202 for detecting a water content contained in the air supplied to the electro-positioner 10 for controlling the opening degree of the control valve 100; A control unit 300 for generating a power cut-off and an alarm of the electric valves 205 and 205 'when the water content detected by the water detection sensor 202 exceeds an upper limit of water; A pair of electric valves 205 and 205 'installed to block compressed air supplied to the electro-positioner 10 under the control of the controller 300; A filler 208 for supplying emergency compressed air to the positioner 10 when the air is supplied to the positioner 10; A pressure switch 209 for detecting a lower pressure limit of the filler 208; And an electric valve 204 which is operated by the pressure switch 209 when detecting the lower pressure limit of the filler 208 to block the pressure-converted air supplied to the control valve 100 by the electric positioner 10. Emergency control device for the control valve for supplying gas to the refining furnace comprising a. The method of claim 1, The control unit 300 has a normally closed contact state and a relay 301 for supplying power input through the power supply terminal 213 to the electric valves 205 and 205 ', and an always open contact state and an alarm device 206. Relay 302 for transmitting an alarm signal, a constant voltage unit 310 for rectifying and outputting power input through the power supply terminal 213, and a detection signal input from the moisture detection sensor 202 An amplifier 304 connected to the negative terminal and a variable resistor 303 for setting the upper limit of moisture, and a signal inverter for inverting the polarity of the signal input from the amplifier 304; 305, an amplifier 306 for amplifying a signal output from the signal inverter 305, a transistor 308 for receiving a signal output from the amplifier 306, and the transistor 308 Connected to the collector and the moisture content is high It is operated in larger when the emergency control device of the control valve for supplying a gas to a refining comprises a relay (309) for switching the contacts of the relays 301 and 302. The method of claim 1, And the moisture detection sensor (202) is mounted inside the emergency control device by a mounting filter (201). The method of claim 1, Emergency control device for a control valve for supplying gas to the refinery, characterized in that a filter (19) is inserted between the electric valve (205, 205 ') for removing water and dust.