KR20010089683A - Method for detecting and controlling the level of liquid metal in an ingot mold - Google Patents

Abstract

The present invention relates in particular to a method light apparatus for detecting and controlling the level of molten metal present in a mold for a continuous casting installation for steel having a measuring member which can be operated up and down to be inserted into the empty space of the mold. As such, molten metal can be supplied to the mold through a settling tube from a supply vessel with a bottom opening that can block. In this case, the level measuring member 42 is connected to the computer 41 through the first signal line 31, and the computer is connected to the first actuator 61 through the first control line 51 and fixed to the first actuator. The level measuring member 42 is attached to the head end of the extended arm 71. The position sensor 43 of the extension arm 71 is connected to the computer 41 through the second signal line 32, and the computer is connected to the second actuator 62 through the second control line 52. The second actuator is connected with a sealing device 81 for blocking the bottom opening 12 of the supply container 11.

Description

METHOD FOR DETECTING AND CONTROLLING THE LEVEL OF LIQUID METAL IN AN INGOT MOLD}

There is an increasing need for level measurement of liquid metals in molds, especially molds for slab sheet continuous casting installations. In case of continuous casting apparatuses when the billet discharge rate is 4m / min to 6m / min, the measurement error can be extremely small, especially when the signal action is faster.

In the case of the method and apparatus described in EP 0 150 670, the eddy current applied to the molten metal as an exploring coil is used as a dimension for the distance between the measuring coil and the molten metal. In this case, the amount of eddy current on the surface of the molten metal is compared with the set point, and the flow rate of the molten metal is adjusted according to the difference between the set point and the present value. In the case of the device disclosed above, the measuring coil is fixed to an induction tube which can be configured to change in height. The maximum distance between the measuring head and the molten metal is about 20 mm. If it is necessary to further lower the level of the metal, the induction pipe can be lowered with the measuring coil. The disadvantage of this device is that it is not a linear measurement. During the casting, an impedance fluctuation occurs in the measurement coil when the metal level changes, because the eddy current applied to the measurement object is represented as ohmic loss. This impedance variation value reaches the control device for unit operation for measuring the flow rate of the outflow pipe of molten metal through the electronic device.

Also known are radiometric devices, for example roentgen imaging of the template with Co ₆₀ as a radioactive source. The radioactive intensity measured on the opposite side depends on the height of the melt filling the mold interior.

In addition to the relatively large average error rate due to statistical variations in the radiation source disintegration rate, the addition of radioactive materials also increases the regular coating.

OBJECT OF THE INVENTION The object of the present invention relates to a method and apparatus for preventing and controlling the above mentioned disadvantages and for detecting and controlling the height at which liquid metal is filled in a mold, and accurately detecting and leveling levels so as to be suitable for use with all the necessary measurements. To control the level quickly and safely in the event of a change.

The thickness of the cast powder can also be measured.

The present invention achieves the above object through the features of claim 1 relating to the method and claim 4 relating to the apparatus.

The invention relates to a liquid metal in a mold of a continuous casting installation for steel, in particular having a measuring head arranged above the molten metal and calculating a spacing from the bath surface. A method and apparatus for detecting and controlling the level of a.

1 is a schematic diagram of an apparatus for detecting and controlling levels in a mold.

2 is a rotary actuator coupled to the measuring head via a swivel cam.

3 is a horizontally movable first actuator connected to the measuring head by a rope.

4 is a measuring unit for detecting level and cast powder thickness.

<Description of Major Symbols in Drawing>

supply

11. Supply vessel

12. Floor opening

13. Settling pipe

casting

21.Mould

Measure

31. First signal line 42

32. Second signal line 71

33. Third signal line

Control

41. Computer

42. Level measurement member

43. Position sensor

44. Layer Thickness Sensor

Control

51. First control line

position

61. First Actuator

62. Second Actuator

63. Third Actuator

64. Piston Stroke Unit

65. Rotating Unit

67. Traction Unit

fixing

71. Extension arm

72. Column

73.Rug

74. Stay Bar

75. Swivel Arm

76. Joint

77. Displacement device

78. Roll

79. Chain Rope

Closure

81. Seals

82. Spigot

83. Slider (13)

84. Sliders for Casting Powder

S. Melt

G. Foundry Powder

The present invention detects the gap between the measuring head and the electrolytic cell surface charged into the mold, and is connected to the measuring head via a connecting member, and the actuator placed outside the mold moves up and down to keep the gap constant. . At the same time the actual position of the connecting member between the actuator and the measuring head is determined and transmitted to the computer. At this time, the control data processed by the computer is supplied to a second actuator connected to an obturator for controlling the flow rate of the liquid metal in the mold.

Since the distance between the measuring head and the surface of the electrolytic cell does not change, no impedance variation of the measuring coil is seen at all. As a result, occurrence of a measurement error can be prevented.

The connecting members connected out of the mold are easy to grasp in the measurement technique. The control of the inflow rate of the liquid metal into the mold via the second actuator in connection with the closure device is therefore very precise, in particular at high speed.

Since the measuring head is held at regular intervals to detect gaps in the molten metal level, the height of the cast powder on the surface of the metal electrolyzer can be simply identified and controlled.

In a preferred embodiment of the invention, the actuator is operated vertically or horizontally or rotationally to detect the up and down motion in the mold of the measuring head. In this case, the connecting member between the actuator and the measuring sensor may be one rod or may be a chain or a rope. These members are all suitable for very harsh environments within the stationary mold area of continuous casting installations.

In another embodiment, an ultrasonic device is inserted which is a layer thickness sensor for detecting cast powder thickness at the same position as the measuring member formed of an inductive component for measuring the distance between the measuring head and the metal surface. In this case, the layer thickness sensor is connected to the computer through the third signal line, the computer is connected to the third actuator through the third control line, and the third actuator is connected to the sealing device for stopping the supply of the casting material.

Embodiments of the invention are illustrated in the accompanying drawings.

1 shows a feed vessel 11 in which the melt S is contained. The supply vessel 11 has a bottom opening 12 with an immersion tube.

The settling tube 13 is charged into the stationary mold 21. The surface of the electrolytic cell of the melt S in the mold is covered with cast powder G.

The level measuring member 42 is fixed to the head end of the stay bar 74 charged into the mold. The stay bar 74 forms a set of extension arms 71 together with lugs 73 and columns 72. Column 72 is formed in piston 64 of the first actuator. The column 72 is formed to be rotatable while being able to move vertically. In order to move the level measuring member 42 away from the mold 21 or close to the mold side, a rotational motion is required.

The level measuring member 42 is connected to the computer 41 through the first signal line 31. The computer 41 is connected to the first actuator 61 which controls the piston stroke unit 64 via the first control line 51.

The position sensor 43 provided in the extension arm 71 is connected to the computer 41 via the second signal line 32, the computer is connected to the second actuator 62 to be suitable for control, the second actuator is The second piston stroke unit 68 is controlled. The second piston stroke unit is connected to the closure device 81 via an extension arm 69 formed of a stopper.

The first actuator 61 shown in FIG. 2 is coupled to the stay bar 74 via a swivel arm 75 and a joint 76. The level measuring member 42 provided at the head end of the stay bar 74 can be controlled at regular intervals from the surface of the melt S electrolyzer in the mold.

The first actuator 61 is fixed on the rotating unit 65, and the level measuring member 42 can be moved away from or close to the mold as required by the rotating unit.

In FIG. 3, the first actuator 61 is formed of a pull unit 67 arranged on the displacement device 77 and has a roll 78 at the head end of the displacement device. This is located. One end of the rope 79 guided by the roll 78 is engaged with the traction unit 67, and the level measuring member 42 is fixed to the other end of the rope. The level measuring member 42 fixed to the rope 79 is loaded into the mold 21. By simply pulling up to the traction unit 67, the level measuring member 42 can be moved to the area above the mold 21, and then the displacement device 77 can be moved to the stop position or the repair position by operating. have.

FIG. 4 shows a level measuring member 42 with all members, as described in FIG. 1. The only difference here is to have a slider 83 instead of a stopper 82 to control the flow rate of the metal melt S.

Complementing the level measuring member 42 shown in FIG. 1, the layer thickness sensor 44 is further provided in FIG. A layer thickness sensor 44 for detecting the layer thickness of the cast powder G on the electrolytic cell surface is connected to the computer 41 via a third signal line 33, and the computer is adapted to control the third control line. It is connected to the third actuator 63 through 53. The third actuator 63 is connected to a slider 84 for cast powder G, which is in a storage container and can be supplied to the mold.

Claims (11)

A method for detecting and controlling the level of liquid metal in a mold of a continuous casting plant for steel having a measuring head disposed above the molten metal and calculating a distance from the bath surface, the method comprising: a) prior to the start of casting, charging the measuring head, which is held through the connecting member of the fixing device disposed separately outside the mold, into the empty space of the mold, b) starting to fill the mold with a metal melt, grasping all changes in the predetermined interval appearing between the metal electrolyzer surface and the measuring head, c) passing the measurements to an external computer in a safer location, d) the computer feeds the processed control data to an actuator fixed to the fixture, the actuator changing the melt level to re-create the proper spacing with the surface of the electrolyzer, up and down the measuring head. Operating step, e) transmitting the actual position of the connecting member between the measuring head and the first actuator to the computer, and f) the computer transmitting the processed control data to a second actuator connected to an obturator for controlling the inflow of liquid metal into the mold; Level detection and control method of a liquid metal, characterized in that consisting of. The method of claim 1, And the first actuator coupled to the measuring head operates vertically, horizontally or rotationally to operate the measuring head up and down in the mold. The method of claim 1, In addition to the level of the liquid metal, controlling the height of the cast powder on the surface of the metal electrolyzer. It can be fed up and down into a mold through a settling tube from a supply vessel with a measuring member capable of being charged up and down into the empty space of the mold and having a bottom opening which can be cut off, especially for continuous casting installations for steel. An apparatus for detecting and controlling the level of molten metal present, The level measuring member 42 is connected to the computer 41 via the first signal line 31, which is connected to the first actuator 61 via the first control line 51, and connected to the first actuator. The level measuring member 42 is mounted at the head end of the fixed extension arm 71, and the position sensor 43 provided on the extension arm 71 is connected to the computer via the second signal line 32. 41, the computer is connected to the second actuator 62 via a second control line 52, the second actuator is sealed to block the bottom opening 12 of the supply container 11 Level detection and control device of the molten metal, characterized in that connected to the device (81). The method of claim 4, wherein The extension arm has a column 72 connected to the piston stroke unit 64, A stay bar 74 disposed in parallel with the column 72 and having a level measuring member 42 fixed to an end thereof; Lug 73 connecting the column 72 and the stay bar 74 Level grasp and control device of the molten metal, characterized in that consisting of. The method of claim 4, wherein The extension arm 71 is composed of a swivel arm 75 coupled with a swivel unit 45, and a joint 76 provided at the end of the swivel arm head is connected to the stay bar 74. And the level measuring member (42) is fixed to the head end of the stay bar. The method according to claim 5 or 6, And a rotary device 66 connected to the piston stroke unit 64 to the rotary unit 65 for allowing the level measuring member 42 to enter or exit while turning into the void of the mold 21. Level detection and control device of molten metal. The method of claim 4, wherein The extension arm 71 is fixedly coupled to the displacement device 77, and a rope or chain 79 can be guided through a roll 78 provided at the head end of the extension arm, and one side of the rope or chain The level measuring member (42) at its end and a traction unit (67) at its other end. The method according to any one of claims 4 to 8, A level measuring member 42 having an induction component for detecting a gap between the measuring head and the molten metal surface and a layer thickness sensor 44 for detecting the layer thickness of the cast powder are provided on the extension arm 71. Level detection and control device of the molten metal, characterized in that fixed. The method of claim 9, And said layer thickness sensor (44) is an ultrasonic device capable of detecting a gap with a cast powder surface. The method according to claim 10 or 9, The layer thickness sensor 44 is connected to the computer 41 through a third signal line 33, and the computer is connected to the third actuator 63 through a third control line 53. Actuator is level detection and control device of the molten metal, characterized in that the connection with the closing device (84) for stopping the casting material supply.