Claims
- 1. A hot dip coating apparatus, comprising:a coating tank with a bottom slit for enabling a steel strip to upwardly run therethrough into said coating tank so that the steel strip is coated as the steel strip is pulled upward; an electromagnetic sealing device including a pair of magnetic field applying means arranged at both sides of said bottom slit so as to oppose each other at a predetermined spacing for applying a magnetic field to molten metal inside said coating tank to hold the molten metal within said coating tank; an overflow dam on said coating tank so that the molten metal that overflows is drained from said coating tank; a molten metal supplying system associated with said coating tank and including an auxiliary tank for melting the coating metal and holding the molten metal therein, a molten metal supply passage through which the molten metal is supplied from said auxiliary tank to said coating tank, and a molten metal drain passage through which the molten metal drained from said coating tank is returned to said auxiliary tank; and buffer means arranged within said coating tank and in fluid communication with the molten metal supply passage for supplying the molten metal with a uniform flow velocity of the molten metal across a breadth of said bottom slit so as to suppress a pulsating flow of the molten metal.
- 2. The hot dip coating apparatus according to claim 1, wherein said coating tank is divided into a plurality of tank sections, said hot dip coating apparatus further comprising moving means associated with each of said tank sections so as to move said tank sections towards and away from the steel strip.
- 3. The hot dip coating apparatus according to claim 1, further comprising a molten metal discharge passage communicating with said buffer means, for discharging the molten metal towards said bottom slit.
- 4. The hot dip coating apparatus according to claim 1, wherein said buffer means comprises a slit-shaped outlet extending in the breadthwise direction of said bottom slit.
- 5. The hot dip coating apparatus according to claim 1, further comprising heating means arranged to heat the molten metal in said molten metal supply passage.
- 6. The hot dip coating apparatus according to claim 1, further comprising dross removing means arranged within or in the vicinity of said auxiliary tank.
- 7. The hot dip coating apparatus according to claim 1, further comprising moving means on both sides of said bottom slit and associated with the respective magnetic field applying means so as to move the associated magnetic field applying means towards and away from said bottom slit.
- 8. The hot dip coating apparatus according to claim 1, further comprising a steel strip profile measuring device upstream of said bottom slit as viewed in the direction of running of the steel strip, and a profile judging device for judging any abnormal profile of the steel strip based on a signal derived from the steel strip profile measuring device.
- 9. The hot dip coating apparatus according to claim 1, further comprising a pair of sealing members for preventing downward leakage of said molten metal, said sealing members being arranged immediately below said bottom slit so as to oppose the steel strip and so as to be brought into and out of contact with the steel strip.
- 10. The hot dip coating apparatus according to claim 9, wherein each of said sealing members includes a heat-resistant belt supported by rotatable rollers.
- 11. The hot dip coating apparatus according to claim 10, wherein at least one of said rollers is power-driven.
- 12. The hot dip coating apparatus according to claim 1, further comprising a pair of gas-jet sealing devices for preventing downward leakage of said molten metal, said gas-jet sealing devices being arranged immediately below said bottom slit so as to oppose the steel strip.
- 13. The hot dip coating apparatus according to claim 1, further comprising a pair of sealing members for preventing downward leakage of said molten metal, said sealing members being arranged immediately below said bottom slit so as to oppose the steel strip and so as to be brought into and out of contact with the steel strip, and a pair of gas-jet sealing devices for preventing downward leakage of said molten metal, said gas-jet sealing devices being arranged immediately below said sealing members so as to oppose the steel strip.
- 14. The hot dip coating apparatus according to claim 1, further comprising sealing members arranged immediately above said bottom slit and made of a material meltable at a temperature not higher than the melting temperature of the coating metal.
- 15. The hot dip coating apparatus according to claim 1, further comprising a steel strip supporting device for guiding the steel strip into said coating tank through said bottom slit, said steel strip supporting device including a deflector roller which deflects the pretreated steel strip so as to run vertically upward, support rollers disposed downstream of said deflector roller, for correcting any warp of the steel strip, a pair of guide rollers disposed down-stream of said support rollers and below said bottom slit of said coating tank, for suppressing vibration of the steel strip, and a molten metal scraping device associated with each of said guide rollers so as to scrape molten metal off said guide roller.
- 16. In a hot dip coating device for coating a steel strip as it is fed upwardly through a slit in a bottom of a coating tank, in which molten metal for coating the strip is circulated through the coating tank via inlets on opposite sides of the slit near the bottom of the coating tank and an outlet at a top of the coating tank, and in which a magnetic field prevents the molten metal from leaking through the slit, the improvement comprising:flow restricting buffer means for making a flow velocity of the molten metal uniform across a breadth of said slit as the molten metal enters the coating tank at the inlets.
- 17. The hot dip coating device of claim 16, wherein said flow restricting buffer means comprises a flow restricting molten metal discharge passageway in said coating tank extending in a breadthwise direction of said slit.
- 18. The hot dip coating device of claim 17, wherein said passageway comprises a sill at a discharge opening of said passageway.
Priority Claims (5)
Number |
Date |
Country |
Kind |
8-349695 |
Dec 1996 |
JP |
|
8-349696 |
Dec 1996 |
JP |
|
8-349697 |
Dec 1996 |
JP |
|
8-349698 |
Dec 1996 |
JP |
|
8-349699 |
Dec 1996 |
JP |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 08/997,608, filed Dec. 23, 1997 and now U.S. Pat. No. 5,965,210.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4169426 |
Kornmann et al. |
Oct 1979 |
|
5665437 |
Frommann et al. |
Sep 1997 |
|
5702528 |
Paramonov et al. |
Dec 1997 |
|
5827576 |
Carter et al. |
Oct 1998 |
|
Foreign Referenced Citations (8)
Number |
Date |
Country |
43 44 939 |
Feb 1995 |
DE |
60-089556 |
May 1985 |
JP |
63-192853 |
Aug 1988 |
JP |
3-079747 |
Apr 1991 |
JP |
8-333661 |
Dec 1996 |
JP |
WO 9318198 |
Sep 1993 |
WO |
WO 9603533 |
Jul 1995 |
WO |
WO 9602683 |
Feb 1996 |
WO |