JPS6313235Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to RH degassing equipment, and is an over-immersion prevention device for the immersion pipe of the RH degassing equipment, which is related to automatic fixed position control when raising and setting a molten steel ladle.

Conventionally, in the RH operation method used in the steel refining process, a flange connection structure has been used to facilitate replacement of submerged tubes when they wear out, and water cooling is used to prevent the flanges from deforming due to radiant heat from the molten steel.

Therefore, in order to prevent a major accident such as a steam explosion in the event that the flange of the dip pipe is accidentally immersed in molten steel during operation and damaged, strict precautions are being taken during operation. It is.

However, since there is no device that automatically detects the fixed position and stops the ascent, the immersion pipe may be over-immersed to the water-cooled flange due to an operational error or malfunction of related equipment, and the water-cooled flange may melt and cause molten steel. There have been many cases in which steam explosions have occurred due to water being sucked in by cooling water.

For this reason, recently, as countermeasures, the operation switches for raising and lowering the receiving ladle have been separated and spaced apart and installed on the operation panel, disk, etc., and chimes and buzzers with different tones are installed when raising and lowering the ladle. We have implemented methods to give warnings to
We also considered using a limit switch, but since the height of the hot water level in the receiving ladle is not always constant,
It was impossible to completely prevent melting of the immersion pipe flange and steam explosion. Furthermore, attempts are being made to improve safety by air cooling the water-cooled flanges of the immersion pipes, but it is currently impossible to prevent the flanges from melting and damage with air cooling.

As mentioned above, the purpose of this invention is to prevent flange melting, prevent over-immersion of immersion pipes, and automatically prevent steam explosions that can lead to serious disasters without human intervention. In the RH degassing device, the overimmersion detection electrode 7 is installed on the working floor 19 at the intermediate position between the RH degassing tank 1 and the immersion pipe flange 2 so that the tip thereof is below the immersion pipe flange 2, and the conductor 8 is made of metal. It is wrapped with a cover 15, the space is filled with refractories 14, the tips of the electrodes 7 are removably connected with joints 18, and external connection terminals 17,
A closed loop detector 10 consisting of a power source 9 is provided, and a signal from the closed loop detector 10 is connected to a pot rise stop signal generator 11, an alarm 12, and a pot lifting device 6. It is an immersion prevention device.

Embodiments of the present invention will be described below based on the configuration shown in FIGS. 1 and 2.

As shown in FIG. 1, the tip of the overimmersion detection electrode 7 attached to the work floor 19 is placed at the intermediate position between the immersion pipe flange 2 and the immersion pipe 3 of the RH degassing tank 1, and the conductor 8,
16 power supply 9 and a closed-loop detector 10 are provided, and the signal of the closed-loop detector 10 is connected to a pot rise stop signal generator 11 and an alarm 12 to form an overimmersion detection electrode.

The general operating procedure during RH degassing is to first put molten steel 5 into the steel receiving ladle 4, move it to the bottom of the RH degassing tank 1, and then move the steel receiving ladle 4 until the immersion pipe 3 is immersed in the molten steel 5 using the ladle lifting device 6. Raise it, stop raising it at a predetermined position, and perform RH treatment.

If the steel receiving ladle 4 rises abnormally due to an operational error or failure of ancillary equipment during the above-mentioned lifting operation, the tip of the over-immersed electrode 7 will be immersed in the molten steel 5 before the immersion pipe flange 2, and the molten steel 5 will be The immersed electrode 7, the conducting wire 8, the power supply device 9, and the closed loop detector 10 constitute a closed loop.

The closed-loop configuration electric signal is input to the pot lifting stop signal generator 11 to automatically stop the lifting of the pot lifting device 6, and at the same time, the alarm 12 is sounded to prevent the immersion pipe flange 2 from being immersed in the molten steel 5. This is to prevent

Next, the detailed structure of the overimmersion detection electrode will be explained based on FIG. 2.

The electrode 7 for detecting over-immersion is the most important element in the practical application of the present invention. As is well known, the environment surrounding the RH degassing tank is a hostile environment with high temperatures and frequent water droplets generated by equipment cooling.

Therefore, in order to increase the reliability of the device of the present invention without causing any failures, the configuration described below is indispensable. An electrode rod 13 having sufficient mechanical strength and a conducting wire 8 are connected by a joint 18, and an external connection terminal 17 is connected to the rear end of the conducting wire 8.

The conductor 8 is surrounded by a metal cover 15 to prevent insulation deterioration due to water droplets and cable burnout due to radiant heat from the molten steel, and the space is filled with a refractory 14. When replacing the immersion tube 3, an electrode rod is used. The electrode rod 13 is connected by a joint 18 so that it can be removed from the conductor 8 to prevent damage.

The present invention uses the above-described configuration to detect the rising limit of the steel receiving ladle with high precision at a fixed position of the immersion pipe even if the height of the hot water level is not constant, and to reliably and automatically stop the rising of the steel receiving ladle. This is an inexpensive device that can completely prevent steam explosions and equipment damage. In recent technology, there is a tendency to air-cool the flanges of immersion pipes in order to prevent explosion accidents caused by over-immersion, but this proposal is an effective means from both air-cooling and equipment maintenance aspects, and has great industrial effects. It is a device.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the overall configuration flow of the present invention, and FIG. 2 is a detailed view of the main parts of the overimmersion detection electrode. 1 is the RH degassing tank, 2 is the immersion pipe flange, 3 is the immersion pipe, 4 is the steel receiving ladle, 5 is the molten steel, 6 is the ladle lifting device, 7 is the overimmersion detection electrode, 8 and 8' are the conductors, and 9 is the electrode, 10 is a closed loop detector, 11 is a pot rise stop signal generator, 12 is a stop alarm, 13 is an electrode rod,
14 is a refractory, 15 is a metal cover, 16 is a conductor, 17 is an external connection terminal, 18 is a joint, and 19 is a work floor.

Claims (1)

[Scope of utility model registration request] In the RH degassing equipment, install the overimmersion detection electrode on the work floor at a position midway between the RH degassing tank and the immersion pipe flange, with the tip of the overimmersion detection electrode under the immersion pipe flange, wrap the conductor with a metal cover, and place it in the space. Filled with refractory, the tips of the electrodes are removably connected with a joint, a closed loop detector consisting of an external connection terminal and a power source is provided, and the signal of the closed loop detector is transmitted to a pot lifting stop signal generator, an alarm, and a pot lifting/lowering device. An over-immersion prevention device for an RH degassing device immersion tube, characterized in that it is connected to the device.