Method for maintaining a temperature of a metal melt

Patent metadata

Field	Value
Publication number	US-9500528-B2
Application number	US-201013390075-A
Country	US
Kind code	B2
Filing date	Aug 5, 2010
Priority date	Aug 10, 2009
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A temperature of a metal melt in a furnace is maintained after blowing away slag from a surface of the metal melt by the flow of oxygen and switching over from oxygen to an inert gas, such as nitrogen. A measured temperature of the metal melt is accepted as a metal melt temperature only when the inert gas flow is in a laminar state and after the measured temperature has fluctuated by a maximum of 1% over a period of at least 2 seconds.

First claim

The invention claimed is:

1. A method for non-contact determination of temperature of a metal melt in a furnace having at least one burner-lance unit which is fed above the metal melt through a furnace wall of the furnace into a furnace chamber, by at least one temperature measuring unit downstream from the at least one burner-lance unit, comprising:
operating the at least one burner-lance unit in lance mode to convey a flow of at least one gas into the furnace chamber at supersonic speed;
blowing away slag from a surface of the metal melt by the flow of the at least one gas;
embodying the flow of the at least one gas over a first period of time by a first gas including oxygen;
switching from the first gas to a second gas that is inert, while retaining the lance mode over a second period of time;
permanently obtaining a metal melt temperature, at least within the second period of time, by detecting an obtained temperature of the metal melt; and
accepting the obtained temperature as a valid measurement of the metal melt temperature when the gas flow is in a laminar state and after the obtained temperature has fluctuated by a maximum of 1% over a third period of at least 2 seconds.

2. The method as claimed in claim 1 , further comprising changing from the second gas to the first gas, after said obtaining the metal melt temperature, while maintaining the lance mode.

3. The method as claimed in claim 2 , wherein said changing from the second gas to the first gas occurs when, over a second period of a maximum of 10 seconds, a fall in the obtained temperature by more than 1% is detected.

4. The method as claimed in claim 3 , wherein changing from the second gas to the first gas occurs as soon a fall in the obtained temperature by more than 5% is detected over the second period.

5. The method as claimed in claim 1 , further comprising repeating said switching and said obtaining.

6. The method as claimed in claim 1 , further comprising detecting, by the at least one temperature measuring unit, a radiation emitted along a longitudinal axis of the burner-lance unit in the direction of the burner-lance unit.

7. The method as claimed in claim 1 , further comprising at least one of controlling and regulating a process variable for a process executing in the furnace chamber, using the metal melt temperature.

8. The method as claimed in claim 1 , wherein the first gas is oxygen and the second gas is nitrogen.

Assignees

• Abel Markus
• MüLLER ALEXANDER
• Nardacchione Domenico
• Siemens Ag

Inventors

• Abel Markus
• MüLLER ALEXANDER
• Nardacchione Domenico

Classifications

• G01J5/004

  by molten metals · CPC title

• G01J5/04

  Casings · CPC title

• G01J5/05 Primary

  Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path · CPC title

• G01J5/00

  Radiation pyrometry, e.g. infrared or optical thermometry · CPC title

• G01J5/02 Primary

  Constructional details · CPC title