JPH0674953B2 - Immersion lance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a dipping lance used for dipping in molten metal to adjust the components of the metal.

[Problems to be Solved by Conventional Techniques and Inventions] Recently, removal of S, removal of P, removal of Si, etc. have been performed as a preliminary treatment of a molten gun and secondary refining. For this treatment, a immersion lance is used in which a metal blow pipe for blowing various treatment agents or treatment gases into a molten metal is covered with a refractory sheath.

As such a lance, it is common to attach a support metal fitting for fixing the refractory sheath to a blow pipe for blowing a treatment agent or a treatment gas, and cast castable refractory material into the lance. The lance has a high melting loss of the refractory, and because it is an integrated structure due to pouring, the refractory is likely to crack due to the expansion difference of the blow pipe and the refractory, and moreover, it is refractory due to thermal spalling due to the temperature difference between immersion and standby. Cracks easily occur on objects. Further, the temperature of the blow pipe becomes high, so that there is a problem that the strength of the blow pipe is easily deteriorated.

Therefore, as seen in Japanese Patent Publication No. 60-1361,
A method to solve the above problems by blocking the refractory material and providing a skimmer between the blow pipe and the refractory material and cooling this skimmer with a gas was investigated, but in this structure, the lower end of the refractory sheath was investigated. Although it is effective in melting damage in the part, the thermal stress becomes large because the refractory is cooled directly, and there is a high risk of gas leakage from the refractory due to cracking. In addition, since the heat exchange of the cooling gas is good, the temperature of the cooling gas rises too high in the upper part of the refractory sheath, and conversely the temperature of the cooling circulation pipe becomes high. Although it has been disclosed to use a connector in the middle of the pipe in order to solve such a problem, it has a drawback that not only the structure becomes complicated but also the amount of gas consumed for cooling increases.

[Means for Solving Problems] Various investigations have been made to improve these problems.
The lower part of the refractory sheath, which is more easily affected by the blow-out nozzle at the lower end, directly cools the refractory sleeve to provide melting resistance, and the refractory sleeve with high thermal conductivity is coated on the inside of the refractory sleeve for cooling effect. In addition to improving the melting resistance, it also reduces thermal stress and suppresses the occurrence of cracks. Regarding the upper part of the refractory sheath, which is less affected by melting damage, an air barrier layer is provided between the refractory sleeve and the cooling circulation pipe to indirectly cool the refractory sleeve to reduce thermal stress. And, it is intended to suppress the temperature rise of the cooling circulation pipe.

The gist of the invention is an immersion lance in which a cooling circulation pipe is provided between a blow pipe and a refractory sheath in which refractory sleeves are stacked. In the lower part of the refractory sheath, a refractory having high thermal conductivity is provided on the inside. The refractory sheath above the refractory sheath is provided with an air-blocking layer so as to be directly cooled by the cooling gas circulating through the cooling circulation pipe. The air-blocking layer is provided between the refractory sheath and the cooling circulation pipe. It is an immersion lance that can be indirectly cooled via the.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Example 1] A blow-in pipe 10 composed of multiple pipes 11 and 12 for injecting a treatment agent, a carrier gas, etc., and a refractory sleeve 21 made by molding castable refractory such as alumina or high alumina in advance. A cooling circulation pipe 30 for injecting and circulating a cooling gas between the refractory sheaths 20 in which
To provide. The cooling circulation pipe 30 is provided with a plurality of inflow pipes 31 that allow the cooling gas to be taken in from the upper intake port 311 and released from the lower intake port 312, and cooled from the intake port 312 of the inflow pipe 31. Pipe for letting out the working gas and discharging it from the exhaust port 322 through the slit 321
It consists of 32 and. In the lower part of the refractory sheath 20, the refractory sleeve 21 is covered with a high thermal conductive refractory 22 such as Si or C, and flows into the inner peripheral surface of the high thermal conductive refractory 22. The outflow pipe 32 is formed so that the cooling gas that has flowed out from the outlet 312 of the cooling pipe 31 comes into direct contact with it and flows out from the slit 321. The refractory sheath 20 above this is formed with the outflow pipe 32 so that the air blocking layer 40 is in contact with the inner peripheral surface.

[Example 2] In the immersion lance of Example 1, a cooling gas was introduced 31
Instead of a plurality of inflow pipes 31 taken in from 1 and discharged from a lower outlet 312, an inflow pipe 31B having a concentric cross-section cylinder is provided outside the blow pipe 10.

311B is the cooling air intake, 312B is the cooling air intake,
Other configurations are the same as those in the first embodiment.

[Effects of the Invention] According to the present invention, as described in detail above, 1) The lower part of the refractory sheath is coated with a high thermal conductive refractory material inside the refractory sleeve to improve the cooling effect, thereby refractory material. Improves melting resistance of the sleeve.

2) In addition, the lower part of the refractory sheath is provided with a refractory material with high thermal conductivity such as SiC inside the refractory sleeve to further improve the melting resistance, but to reduce the thermal stress and to prevent cracks. Dramatically improve the risk of gas leak prevention based on

3) In the upper part of the refractory sheath, the refractory sleeve is cooled through the barrier layer, so that the thermal stress is relieved and cracks in the refractory and the temperature rise of the cooling circulation pipe are suppressed.

4) A cooling effect can be expected with a small gas consumption.

And so on.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the lance of the present invention, and FIG.
1 is a cross-sectional view of the lance of the present invention taken along the line AA in FIG. 1, FIG. 3 is a cross-sectional view of the lance of the present invention taken along the line BB of FIG. 1, and FIG. FIG. 5 is a longitudinal sectional view showing another embodiment of the invention lance, FIG. 5 is a transverse sectional view of the lance of the invention taken along the line AA in FIG. 4, and FIG. 6 is a view taken along the line BB in FIG. It is a cross-sectional view of the present invention lance. 10 …… Blown pipe 20 …… Refractory sheath 21 …… Refractory sleeve 22 …… High thermal conductive refractory 30 …… Cooling circulation pipe 40 …… Air barrier layer

Claims (1)

[Claims] 1. A submerged lance in which a cooling circulation pipe is provided between a blow pipe and a refractory sheath in which a refractory sleeve is superposed, and in the lower part of the refractory sheath, the inside is covered with a high thermal conductive refractory. The refrigerating sheath above the refrigeration circulation pipe is provided with an air blocking layer between the cooling circulation pipe and the cooling gas, and the refractory sheath is provided with an air blocking layer. Immersion lance characterized in that it can be indirectly cooled via.