JPH04270049A - Stopper device for continuous caster and controller for molten metal surface level - Google Patents

Abstract

PURPOSE:To control a molten metal surface level for a continuous caster at high accuracy by using a stopper device positioning ascending/descending position of a stopper rod for opening/closing an opening hole part in the pouring nozzle into a tundish in good accuracy. CONSTITUTION:A screw shaft 13 is juxtaposed on the upper end of the stopper rod 10 facing the lower end to the opening hole end of the pouring nozzle 4 in the tundish T and a nut member 15 screwed with this screw shaft 13 is driven to rotate with a hydraulic motor 12. Then, the stopper rod 10 is ascended/descended by the screwing action of the screw shaft 13 to the nut member 15 and positioned at high accuracy. Further, feeding oil pressure into the hydraulic motor 12 is controlled with the action of a four-directional spool valve 8 provided with the built-in spool shifted at high accuracy with the revolution of a pulse motor 7, and this pulse motor 7 is driven with driving pulse outputted from a level control part 6 in order to cancel the difference between the detected value of molten metal surface level in the mold M with a level detector 30 and the aimed level to execute the molten metal surface level control.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stopper device used to adjust the amount of molten metal poured into a mold for continuous casting, and a molten metal level control device using this stopper device.

0002

[Prior Art] When operating a continuous casting machine, it is necessary to prevent the occurrence of various inconveniences such as overflow of molten steel from the mold and breakouts that would force the suspension of operation, as well as to cool and solidify the molten steel within the mold. In order to stabilize the condition and improve the quality of product slabs, level control is performed to maintain the level of the molten metal inside the mold at an appropriate level.

This level control is achieved by disposing a level meter facing the surface of the molten steel inside the mold, and by attaching an opening/closing means to the nozzle for pouring the molten metal into the mold, so that the level can be detected by the level meter. The current level of the molten metal is compared with a predetermined target level, and the opening degree of the opening/closing means is adjusted to eliminate the deviation between the two, and the amount of molten metal poured into the mold is adjusted.

[0004] As the opening/closing means, a gate plate is disposed in the middle of the pouring nozzle extending from the tundish toward the mold, and is perpendicular to the axis of the pouring nozzle. A sliding nozzle that opens and closes the pouring nozzle by sliding is generally used, but when this sliding nozzle is adopted for a small-section continuous casting machine where the amount of poured metal into the mold is constantly small, the sliding nozzle of the gate plate Molten steel tends to solidify and adhere to moving parts, easily causing clogging, so in small-section continuous casting machines, a stopper device as shown in FIG. 3 is used as an opening/closing means in place of a sliding nozzle.

As shown in this figure, the conventional stopper device 2 has the following features:
A stopper rod 20 is disposed inside a tundish T for storing molten steel 3 with its lower end facing the opening of a pouring nozzle 4 that opens at the bottom of the tundish T, and is made to protrude above the surface of the molten steel 3. The upper end of the stopper rod 20 of the octopus and the output rod of a work cylinder 21 fixedly installed outside the tundish T are connected via a connecting rod 22, and the pouring nozzle 4 is moved by the forward and backward movement of the work cylinder 21. The stopper rod 20 is raised and lowered along the axis, and the tip of the stopper rod 20 opens and closes the opening of the pouring nozzle 4.

That is, in this stopper device 2, the flow of molten steel 3 always exists around the entire circumference of the stopper rod 20, regardless of the nozzle opening degree, which is determined according to the vertical position of the stopper rod 20, so that clogging occurs. Therefore, the amount of poured molten metal can be stably adjusted in a low flow rate region.

[0007]

However, in the stopper device 2 in which the molten steel 3 flows around the entire circumference of the stopper rod 20 as described above, when compared with a sliding nozzle, the ratio of change in the pouring amount to the unit operation amount is lower. (
The problem is that the flow rate gain) is large, and fine positional adjustment is required within a limited lifting stroke shown as L in the figure, and extremely high positioning accuracy is required when lifting and lowering the stopper rod 20.

Therefore, in recent years, a direct-acting cylinder with excellent resolution, such as a stepping cylinder, has been used as the work cylinder 21 to meet the above-mentioned requirements, but there is a limit to the improvement in resolution with a stepping cylinder. When positioning the stopper rod 20, the deflection of the connecting rod 22 that connects the stopper rod 20 with the work cylinder 21 acts as a disturbance, so the reality is that satisfactory positioning accuracy cannot be obtained even when a stepping cylinder is used. Therefore, in the level control of the molten metal in which the amount of poured molten metal is adjusted using the stopper device 2, it is difficult to stabilize the molten metal level with high precision, and it is difficult to cope with an increase in the pouring speed. was there.

The present invention has been made in view of the above circumstances, and provides a stopper device capable of positioning a stopper bar functioning as a means for opening and closing a pouring nozzle with high precision.
Another object of the present invention is to provide a hot water level control device that can stabilize the hot water level with high precision by using this stopper device.

0010

[Means for Solving the Problems] A stopper device for a continuous casting machine according to the present invention includes a stopper rod whose tip faces the open end of a pouring nozzle into a mold into a tundish, and a lifting mechanism for the stopper rod. A stopper device for a continuous casting machine, which opens and closes the opening by raising and lowering a stopper rod according to the operation of the lifting mechanism to adjust the amount of molten metal poured into the mold,
The lifting mechanism includes a screw shaft coaxially connected to the base end of the stopper rod, a nut member screwed onto the screw shaft, and a hydraulic motor that applies rotational force about the axis to the nut member. The hot water level control device according to the present invention is characterized in that it detects the hot water level inside the mold during operation of a continuous casting machine equipped with the stopper device, and compares this with a predetermined target level. In the continuous casting machine, the level control device operates the lifting mechanism to adjust the amount of molten metal poured into the mold in order to eliminate the deviation of the molten metal. It is characterized by comprising a four-way spool valve, a pulse motor that applies a moving force to the spool, and a calculation control section that calculates the rotation direction and amount of rotation of the pulse motor based on the deviation.

[0011]

[Operation] In the present invention, a hydraulic motor rotates a nut member that is threaded onto a threaded shaft coaxially connected to the base end of a stopper rod, and the threading of the threaded shaft relative to the nut member causes The stopper rod is raised and lowered to open and close the pouring nozzle at the tip of the spool rod. In addition, a pulse motor that is driven based on the deviation between the detection result of the hot water level inside the mold and the target level, and a four-way spool valve that is equipped with a spool that operates according to the rotation of this motor are provided.
The hydraulic motor is rotated by the hydraulic pressure supplied from the directional spool valve to raise and lower the stopper rod, and the level of the hot water inside the mold is adjusted with high precision and high response.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing embodiments thereof. FIG. 1 is a schematic diagram showing a state in which molten metal level control is performed in a continuous casting machine equipped with a stopper device according to the present invention.

In the figure, T is a tundish that temporarily stores molten steel 3 supplied from a ladle (not shown), adjusts the flow rate, and sends it out. A cylindrical mold M is disposed below the tundish T at an appropriate distance apart, and has an opening at the top and bottom. A pouring nozzle 4 with an open end is extended. The molten steel 3 in the tundish T is injected into the mold M through the pouring nozzle 4, is cooled by contacting the water-cooled inner wall of the mold M, and is poured into a mold whose outside is covered with a solidified shell 50. The piece 5 is continuously pulled out from the lower opening of the mold M.

A level detector 30 is disposed on the upper part of the mold M so as to face the surface of the molten steel 3 retained in the mold M, and during the operation of the continuous casting machine as described above, the mold M
The level of the hot water inside is detected by this level detector 30, and the deviation between this detected level and a predetermined target level is given to the level control section 6. The level control unit 6 performs calculations as will be described later to eliminate the deviation, and operates to adjust the amount of molten metal poured into the mold M.

The amount of molten steel 3 injected from the tundish T into the mold M is adjusted by the operation of the stopper device 1 according to the present invention. This stopper device 1 suspends from a gearbox 11 fixedly installed on the upper part of a tundish T, and a stopper rod 10 whose lower end faces the opening of a pouring nozzle 4 in the tundish T is connected to the gearbox 11. 11
The opening is opened and closed by raising and lowering the opening by rotation of a hydraulic motor 12 attached to the opening.

The upper end of the stopper rod 10 is connected to the gear box 1.
It is coaxially connected via a joint 14 to a screw shaft 13 that is supported slidably in the vertical direction within the gear box 11, and a nut member 15 is screwed onto the screw shaft 13 inside the gear box 11. It's closed. The outer periphery of the nut member 15 is a spur gear, and is meshed with a spur gear 16 fitted onto the rotating shaft of the hydraulic motor 12. The rotation of the hydraulic motor 12 is transmitted to the nut member 15 via the spur gear 16, and the accompanying rotation of the nut member 15 is transmitted to the screw shaft 13.
The stopper rod 10 connected to the screw shaft 13 moves up and down. In addition, in order to perform this lifting and lowering smoothly and to reduce the torque generated by the hydraulic motor 12, the screw shaft 1 is
3 and the nut member 15 are preferably ball screws.

The hydraulic motor 12 has a four-way spool valve 8 equipped with a spool that operates according to the rotation of the pulse motor 7.
The stopper rod 10 is driven to rotate in both forward and reverse directions by the hydraulic pressure supplied from the hydraulic motor 12. Since the opening of the molten metal pouring nozzle 4 is opened and closed accordingly, the amount of molten metal poured into the mold M can be changed by controlling the rotation of the hydraulic motor 12. At this time, the rotation of the hydraulic motor 12 is converted into the vertical movement of the stopper rod 10 via the screw mechanism consisting of the screw shaft 13 and the nut member 15.
The vertical movement of the stopper rod 10 per unit rotation of the hydraulic motor 12 is small, and the vertical position of the stopper rod 10 can be finely adjusted. There is little risk of deflection causing disturbance during the process, and the vertical position of the stopper rod 10 and the amount of molten metal poured into the mold M determined accordingly can be adjusted with high precision.

The four-way spool valve 8, which controls the hydraulic pressure supplied to the hydraulic motor 12, has a valve chamber 81 having a circular cross section formed at the axial center of the housing 80, as shown in FIG.
A spool 82 is fitted inside. The spool 82 is restricted from rotating within a guide chamber 83 connected to one side of the valve chamber 81, and can only slide in the axial direction. Further, on the other side of the spool 82, there is a threaded shaft 8 coaxially therewith.
A nut member 85 that is threaded onto the threaded shaft 84 is fitted onto the rotating shaft of the pulse motor 7 fixedly attached to the same end of the housing 80 . When the pulse motor 7 rotates, the nut member 8
5, the screw shaft 84 screws forward, and the spool 82 connected to the screw shaft 84 slides.

Five annular grooves 81a to 81e are formed on the inner periphery of the valve chamber 81 at equal intervals in the axial direction, and the annular groove 81c located in the center is connected to the hydraulic motor 12. The two annular grooves 81a and 81e are connected to the oil pressure source P (see Fig. 1) that generates the feed oil pressure, and the two annular grooves 81a and 81e are connected to the oil tank maintained at a low pressure state.
81b and 81d are respectively communicated with two pressure guiding ports (a normal rotation port and a reverse rotation port) of the hydraulic motor 12. Further, on the outer periphery of the spool 82 that slides within the valve chamber 81, two annular grooves 8 are provided at a predetermined distance apart in the axial direction.
2a and 82b are formed as shown.

FIG. 2 shows that the spool 82 is located at the center of the sliding range (
At this time, the annular grooves 82a and 82b on the outer circumference of the spool 82 communicate with the annular grooves 81b and 81d on the inner circumference of the valve chamber 81, respectively, and the annular groove 81c connected to the hydraulic pressure source P and the oil Annular groove connected to the tank 81a
, 81e are all closed at the outer periphery of the spool 82, so hydraulic pressure is not supplied to the hydraulic motor 12, the hydraulic motor 12 does not operate, and the stopper rod 10 of the stopper device 1 is moved to its current lifting position. is maintained.

On the other hand, when the spool 82 moves from the neutral position,
When sliding upward in the figure, one of the annular grooves 82a on the outer periphery of the spool 82 corresponds to the annular groove 8 on the inner periphery of the valve chamber 81.
1b and the annular groove 81c, and the hydraulic pressure introduced into the annular groove 81c from the hydraulic pressure source P is transmitted through the annular grooves 82a and 8.
1b to the normal rotation port, and in response to the normal rotation of the hydraulic motor 12 generated by this feeding hydraulic pressure, the stopper rod 1
0 will move upward, and the amount of molten metal poured into the mold M will increase. Conversely, when the stopper 82 slides downward, the stopper rod 10 moves downward in response to the reverse rotation of the hydraulic motor 12, and the mold M
The amount of hot water poured into the tank is reduced.

The level control section 6 is provided with the deviation between the level detected by the level detector 30 and the target level.
The amount of rotation generated in the hydraulic motor 12, which is the driving source of the stopper device 1, due to the unit rotation of the pulse motor 7, which is the driving source of the directional spool valve 8, and the unit lifting amount of the stopper rod 10 caused by this, are stored. , the amount of opening change required for the stopper device 1, that is, the amount of elevation of the stopper rod 10, is determined by a speed-type PID calculation using the deviation, and then this is divided by the unit amount of elevation and the amount of elevation is determined to be applied to the pulse motor 7. The necessary rotation direction and rotation amount are calculated, and the forward rotation pulse or reverse rotation pulse corresponding to the calculation result is applied to the pulse motor 7.
The pulse motor 7 is actuated by being applied to the drive circuit 70 of the pulse motor 7.

The level control unit 6 also receives information from a rotation amount detector 17 attached to the rotation shaft of the hydraulic motor 12, indicating the rotational position of the hydraulic motor 12, that is, the current opening degree of the stopper device 1. The drawing speed of each piece 5 is given, and the level control unit 6 uses these feedback signals, the opening change amount at each control point, and the detection level by the level detector 30 to adjust the stopper device 1.
The model reference type adaptive control is performed by identifying the parameters in and modifying various gains in the above-mentioned calculations. Stopper rod 10 in stopper device 1
is constantly exposed to the molten steel 3 in the tundish T, and will melt away in a relatively short period of time, but changes in flow characteristics due to this melting damage will be compensated for by the aforementioned adaptive control, so it will not last for a long time. It becomes possible to control the hot water level with high precision over the entire range.

[0024]

As described in detail above, the stopper device according to the present invention has a screw shaft coaxially connected to a stopper rod screwed into a nut member, the nut member being rotationally driven by a hydraulic motor, Since the stopper rod is raised and lowered by the threaded movement of the threaded shaft relative to the nut member, it is possible to obtain significantly higher resolution than in the past, and fine position adjustment is possible within a limited raising and lowering stroke. In addition, in the hot water level control device according to the present invention using this stopper device, a spool driven by a pulse motor is provided.
Since the hydraulic pressure supplied to the hydraulic motor is controlled by the directional spool valve, the hydraulic motor can be driven to rotate with high responsiveness, and the accompanying rise and fall of the spool rod allows for precise control of the amount of molten metal poured into the mold. The present invention has excellent effects such as being able to adjust well, stabilizing the molten metal level inside the mold with high precision, being able to cope with higher pouring speeds with a margin, and contributing to improved productivity. play.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a state in which molten metal level control is performed in a continuous casting machine equipped with a stopper device according to the present invention.

FIG. 2 is a longitudinal sectional view of a four-way spool valve that controls hydraulic pressure supplied to a stopper device according to the present invention.

FIG. 3 is a schematic diagram of a conventional stopper device.

[Explanation of symbols]

1 Stopper device 3 Molten steel 4 Pouring nozzle 6 Level control section 7 Pulse motor 8 4-way spool valve 10 Stopper bar 11 Gearbox 12 Hydraulic motor 13 Screw shaft 15 Nut member 81 Valve chamber 82 Spool M Mold T Tundish

Claims (2)

[Claims] Claim 1: A stopper rod whose tip faces the opening end of a pouring nozzle into a mold into a tundish, and an elevating mechanism for the stopper rod, the stopper rod being moved up and down in accordance with the operation of the elevating mechanism. In the stopper device for a continuous casting machine that opens and closes the opening to adjust the amount of molten metal poured into the mold, the elevating mechanism includes a threaded shaft coaxially connected to the base end of the stopper rod, and a threaded shaft coaxially connected to the base end of the stopper rod; A stopper device for a continuous casting machine, comprising: a nut member that is threaded onto a shaft; and a hydraulic motor that applies rotational force about the shaft center to the nut member. 2. When operating a continuous casting machine equipped with the stopper device according to claim 1, the level of molten metal inside the mold is detected, and the lifting mechanism is operated to eliminate the deviation between this level and a predetermined target level. The molten metal level control device for a continuous casting machine that adjusts the amount of molten metal poured into the mold includes a four-way spool valve that controls the hydraulic pressure supplied to the hydraulic motor by moving the spool, and a moving force for the spool. 1. A liquid level control device for a continuous casting machine, comprising: a pulse motor that provides a rotational speed; and a calculation control unit that calculates a rotation direction and rotation amount of the pulse motor based on the deviation.