JPH0313936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding nozzle drive device in a tundish of a continuous casting machine.

In a continuous casting machine, molten metal in a ladle is injected into a mold via a tundish. It is extremely important to minimize fluctuations in the level of the molten metal in the mold in order to maintain good quality of the slab, and for this reason, the opening degree of the sliding nozzle of the tundish is adjusted to keep the level of the molten metal in the mold as small as possible. It is automatically controlled to keep it constant.

By the way, the driving device for this sliding nozzle is disclosed in Japanese Patent Application No. 56-45903 previously filed by the inventor, as shown in _FIG . The third hydraulic cylinder 13 ₂ is driven, and the movement is further transmitted to a third hydraulic cylinder 13 ₃ by hydraulic pressure to drive the sliding nozzle 12 . However, this method is extremely complicated and has caused problems such as a rise in equipment costs.

In order to solve these problems, the present invention provides a device for driving a sliding nozzle with a single hydraulic cylinder.The present invention is characterized in that a hydraulic cylinder with a built-in position detector is used as the hydraulic cylinder. It is in. This will be explained in detail below.

There is a reason why the conventional drive method takes the complicated form shown in FIG. One of them is to keep the position detector 20 for detecting the amount of movement of the sliding nozzle 12, which is essential for automatic control of the opening degree of the sliding nozzle 12, as far away from the sliding nozzle 12 as possible, so as to avoid the influence of heat. The purpose is to protect the detector 20. That is, conventionally, the position detector 20 is attached to the rod of the hydraulic cylinder via a link mechanism, so it is strongly affected by heat from the molten metal, and the sliding nozzle 12
Therefore, it could not be attached to the third hydraulic cylinder ₁₃₃ , etc., which directly drives the engine.

Recently, in the field of position detectors and hydraulic cylinders, several hydraulic cylinders with built-in position detectors have been developed. one of them as the second
To explain with the drawing, an inner tube 3 is fixed in an outer tube 2 having ports 1, 1, and a hollow piston rod 5 is slidably inserted between the outer tube 2 and the outer tube 2 through a packing 4, and fixed therein. A detection rod 6 moves within a detector body 7 fixed inside the inner tube 3, and the position of the piston rod 5 is electrically detected from a terminal 9 via a cord 8.

Although it can be expected that such a hydraulic cylinder has various protective effects on the internal position detector, the area near the sliding part of the tandem is in a very special atmosphere where it is directly affected by molten steel. The present inventors found that when a hydraulic cylinder with a built-in position detector as described above is placed near a sliding nozzle, in addition to the "thermal shielding effect" provided by the cylinder tube, there is also a "forced" effect due to the circulation of pressure oil within the cylinder tube. "Cooling effect"
Since this can be expected, we thought that the position detector inside the cylinder tube could be effectively protected from external heat. Based on this idea, we used this hydraulic cylinder with a built-in position detector as the third hydraulic cylinder 13 ₃ (Fig. 1) closest to the sliding nozzle 12, and attempted to drive the sliding nozzle 12 using only this hydraulic cylinder. As a result, it was discovered that the position detector did not suffer any problems and there were no problems with its durability, even though the location was under extremely harsh conditions where it was directly affected by the heat of the molten metal.

The present invention has been made based on this knowledge, and includes a hollow piston rod 5 that is slidably inserted into an outer tube 2 having a hydraulic port 1, and an inner piston rod that is sealed with a seal and has one end fixed to the outer tube. Along with installing tube 3,
A detection rod 6 and a detector body 7 forming a non-contact position detector are inserted into the inner tube, and one of the detection rod and the detector body is fixed in the inner tube, and the other is inserted into the piston rod. Hydraulic cylinder 13 with built-in rod position detector configured by being fixed to
The tip of the piston rod 5 of the hydraulic cylinder 13 is mechanically connected to the sliding nozzle movable platen 12b of the tundish of the continuous casting machine. 18
Then, the measured signal a from the hot water level detector 14 is compared with the hot water level setting signal b, and the position of the piston rod 5 corresponding to the opening degree of the slide nozzle 12 that makes the deviation zero is set as the command signal c. The arithmetic and control device 15 outputs to the servo amplifier 17, the command signal c from the arithmetic and control device 15 is inputted, and the rod 5 position actual measurement signal d from the position detector built in the hydraulic cylinder 13 is inputted. The gist of this invention is a tundish slide nozzle driving device characterized in that it is equipped with a servo amplifier 17 that outputs an operation signal e to a servo valve 18 to make the rod position actual measurement signal d match the command signal c.

The device of the present invention having the above configuration greatly simplifies the hydraulic system and significantly lowers its cost. It also directly drives the sliding nozzle and improves the control responsiveness of the hot water level so that the hot water level is always maintained at a constant level. This has many effects, such as keeping the value constant and accurate.

Next, the apparatus of the present invention will be explained in more detail with reference to the drawings.

In FIG. 3, 10 is a mold, 11 is a tundish, and 12 is a sliding nozzle. The sliding nozzle 12 is a fixed platen 12a, a movable platen 12b, and an immersion nozzle 12 that reaches inside the mold 10.
The nozzle opening degree is adjusted by driving a hydraulic cylinder 13 with a built-in position detector that is mechanically connected to a movable platen 12b. The detailed structure of this hydraulic cylinder 13 is as shown in FIG. 2, but it goes without saying that the structure is not limited thereto.

Reference numeral 14 denotes a hot water level detector using radiation or the like, and its output signal, that is, a hot water level actual measurement signal a, is inputted to a digital arithmetic and control unit 15 via an appropriate interface.
This arithmetic and control device 15 also inputs a hot water level setting signal b, and outputs a rod position command signal c of the hydraulic cylinder 13 corresponding to the nozzle opening such that there is no deviation between this signal b and the above-mentioned actual measurement signal a. /A
The signal is output to a servo amplifier 17 via a converter 16. The servo amplifier 17 receives a signal from a position detector (see Fig. 2) built into the hydraulic cylinder 13, that is, a rod position actual measurement signal d.
is input, and an operation signal e is sent to the servo valve 18, which is a drive device for the hydraulic cylinder 13, until this signal d matches the command signal c.
Reference numeral 19 indicates a hydraulic pressure source for this servo valve 18.

According to the above configuration, when the hot water level in the mold 10 matches the set value, there is no deviation between the actual hot water level measurement signal a and the same set signal b, so the servo amplifier 17 and the servo valve 18 and hydraulic cylinder 13 maintain their current state, but
When the hot water level deviates from the set value, the servo amplifier 17 and servo valve 18 perform a new operation according to the deviation, thereby operating the hydraulic cylinder 13, but the signal from the position detector built into the cylinder The piston rod 5 is moved forward or backward so that the temperature matches the command signal, and the movable plate 12b of the sliding nozzle 12 slides to eliminate the deviation and return the hot water level to its set value.

According to the sliding nozzle drive device of the present invention, since only one hydraulic cylinder is required, the device can be greatly simplified, and not only can the cost be greatly reduced, but the nozzle opening degree can be Since the detection is directly connected to the nozzle, the detection accuracy is improved, and in combination with the fact that the hydraulic pressure of the servo valve is directly transmitted to the work cylinder of the sliding nozzle, the nozzle opening degree and eventually It is possible to significantly improve the control responsiveness of the hot water level. FIG. 4 shows the results of actual measurements of the step responsiveness of the hydraulic servo in the conventional device and the device of the present invention. The device of the present invention has significantly improved dead time, settling time, and hysteresis.

Regarding the durability of the position detector, as mentioned above, the cylinder tube effectively shields external heat, and the pressure oil circulating inside the cylinder tube acts as a refrigerant to forcibly discharge the heat inside the tube to the outside. The position sensor is placed under the same conditions as when it is installed far from the sliding nozzle, thereby preventing wear and tear on the position sensor due to heat, and demonstrating durability that does not pose a problem in practical use. .

It goes without saying that if a pressure oil cooling device is attached to the hydraulic circuit of the hydraulic cylinder with a built-in position detector, the cooling ability of the position detector will be further increased.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional sliding nozzle drive device, Fig. 2 is an explanatory diagram of the structure of a hydraulic cylinder with a built-in position detector suitable for use with the drive device of the present invention, and Fig. 3 is an explanatory diagram of the drive device of the present invention. FIG. 4 is a graph showing the effects of implementing the present invention. In the figure, 2: outer tube, 3: inner tube,
5: piston rod, 6: detection rod, 7: detector body, 10: mold, 11: tundish, 12:
Sliding nozzle, 13, 13 ₁ to 13 ₃ : Hydraulic cylinder, 14: Hot water level detector, 15:
Arithmetic control device, 16: D/A converter, 17: Servo amplifier, 18: Servo valve, 19: Hydraulic source,
20: Position detector.

Claims (1)

[Claims] 1. A hollow piston rod 5 is slidably inserted into an outer tube 2 having a hydraulic port 1, and an inner tube 3 is provided inside the hollow piston rod with a seal sealed and one end fixed to the outer tube. A detection rod 6 and a detector body 7 forming a contact type position detector are inserted, one of the detection rod and the detector body is fixed in the inner tube, and the other is fixed in the piston rod. The tip of the piston rod 5 of the hydraulic cylinder 13 with a built-in rod position detector is connected to the sliding nozzle movable platen 12 of the tundish of the continuous casting machine.
b mechanically connected to the mold, and a hot water level detector 1 is attached to the mold.
4, and a servo valve 18 that controls the operation of the piston rod 5 of the hydraulic cylinder 13 receives an actual measurement signal a from the hot water level detector 14.
an arithmetic and control device 15 that compares and calculates the position of the piston rod 5 with the hot water level setting signal b and outputs the position of the piston rod 5 corresponding to the opening degree of the slide nozzle 12 to make the deviation zero to the servo amplifier 17 as a command signal c;
The command signal c from the arithmetic and control unit 15 is input, and the actual rod 5 position measurement signal d from the position detector built in the hydraulic cylinder 13 is input, and the actual rod position signal d matches the command signal c. A slide nozzle drive device for a tundish, comprising a servo amplifier 17 that outputs an operation signal e to a servo valve 18.