Device for hot dip coating metal strip including a snout and an extension piece

Patent metadata

Field	Value
Publication number	US-9453275-B2
Application number	US-201414765691-A
Country	US
Kind code	B2
Filing date	Feb 4, 2014
Priority date	Feb 5, 2013
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

An apparatus for hot dip coating metal strip is disclosed having a dip bath vessel ( 4 ), a snout ( 6 ) which opens into the dip bath vessel for introducing a metal strip ( 1 ) which is heated in a continuous furnace into the dip bath, and a deflecting roller ( 7 ) which is arranged in the dip bath vessel for deflecting the metal strip ( 1 ) which enters into the dip bath in a direction which points out of the dip bath. The snout ( 6 ) is provided with a shaft-shaped snout extension piece ( 6.1 ) for increasing the snout dipping depth, the internal width of the snout extension piece ( 6.1 ) tapering toward its outlet opening ( 6.15 ) at least over a part length of said snout extension piece ( 6.1 ). As a result, an increase or maximization of the eddy flow in the molten metal at or close to the metal strip ( 1 ) and therefore improved homogenization of the molten metal in the region of the strip is achieved, as a result of which slag-induced surface defects on the surface of the coated metal strip ( 1 ) can be avoided.

First claim

The invention claimed is:

1. An apparatus for hot dip coating a metal strip, comprising a dip bath vessel including molten metal providing a dip bath surface, a snout which opens into the dip bath vessel for introducing the metal strip into said dip bath vessel, said hot dip coating metal strip is heated in a continuous furnace before being introduced into the dip bath vessel, and a deflecting roller which is arranged in the dip bath vessel for deflecting the metal strip in a direction which points out of the dip bath vessel, wherein the snout is provided with a snout extension piece for increasing a snout dipping depth, an internal width of the snout extension piece tapering toward an outlet opening at least over a part length of the snout extension piece, said snout extension piece is shaft-shaped,
wherein the snout extension piece has a connector section, a lower end of the snout protrudes into the connector section beneath the dip bath surface, said connector section includes a receiving space located beneath the dip bath surface and said receiving space is located beneath the lower end of the snout and above the snout extension piece, and
wherein at least one feed channel is defined between the lower end of the snout and the snout extension piece for the separate addition of coating material or at least one alloying additive into the snout and/or into the snout extension piece.

2. The apparatus as claimed in claim 1 , wherein the internal width of the snout extension piece tapers constantly toward the outlet opening at least over a part length of said snout extension piece.

3. The apparatus as claimed in claim 1 , wherein the internal width of the snout extension piece tapers toward the outlet opening at least over a part length of the snout extension piece in a stepped manner in the form of one or more internal width steps and/or in the form of snout wall sections which are angled away differently with respect to one another.

4. The apparatus as claimed in claim 1 , wherein the outlet opening or a narrowest point of the snout extension piece has a clear internal width of at most 120 mm.

5. The apparatus as claimed in claim 1 , wherein the snout extension piece ends at a spacing in a range from 100 mm to 400 mm with respect to a circumferential face of the deflecting roller.

6. The apparatus as claimed in claim 1 , wherein a length of the snout extension piece is dimensioned in such a way that the snout dipping depth is at least 400 mm during the hot dip coating of the metal strip.

7. The apparatus as claimed in claim 1 , wherein the snout extension piece is provided with at least one separate channel, through which molten metal can flow out of the dip bath vessel in a direction of a molten metal surface in the snout in case of negative pressure in the snout or in case of lowering of the molten metal surface in the snout with respect to a molten metal surface outside the snout.

8. The apparatus as claimed in claim 7 , wherein the at least one separate channel is arranged on an outer side of the snout extension piece.

9. The apparatus as claimed in claim 7 , wherein the at least one separate channel opens at a lower end of the snout extension piece.

10. The apparatus as claimed in claim 7 , wherein the at least one separate channel has an end section which opens above a bottom of the connector section in a throat region thereof.

11. The apparatus as claimed in claim 4 , wherein the clear internal width is at most 100 mm.

12. The apparatus as claimed in claim 5 , wherein the spacing is in the range from 100 mm to 300 mm.

13. The apparatus as claimed in claim 1 , wherein a length of the snout extension piece is dimensioned in such a way that the snout dipping depth is at least 500 mm during the hot dip coating of the metal strip.

14. The apparatus as claimed in claim 1 , wherein a length of the snout extension piece is dimensioned in such a way that the snout dipping depth is at least 600 mm during the hot dip coating of the metal strip.

Assignees

• Thyssenkrupp Steel Europe Ag

Inventors

• Bergen Jegor
• Spelleken Frank
• Peters Michael
• Ruthenberg Manuele
• Macherey Friedhelm
• Spelz Florian

Classifications

• C23C2/40 Primary

  Plates; Strips · CPC title

• B05C11/06

  with a blast of gas or vapour · CPC title

• Y10S118/19

  Wire and cord immersion · CPC title

• B05D1/18

  performed by dipping · CPC title

• B05C3/125

  the work being a web, band, strip or the like · CPC title