Patent Publication Number: US-2003227112-A1

Title: Metal making lance with disposable sensors

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates in general to metal making lances and, more particularly, to metal making lances including sensor means for monitoring conditions within a metal making vessel.  
       BACKGROUND OF THE INVENTION  
       [0002] It has long been known to use probes, monitors or other sensor means to determine characteristics of metal that is being treated in a metal making vessel as well as the operating conditions of the vessel itself. The sensed data, which may include temperature, gas or other constituent concentration, or some other condition, are gathered and processed at or near real-time, typically by computer, and provide the vessel operator with important information about the progress or status of the metal making process occurring in the vessel. Metal making systems incorporating such technology often include means for automatically correcting the metal making process, e.g., by adding more or less of heat, gas and/or particulate matter to the vessel, if the sensed data do not correspond with expected conditions at a particular phase of the process.  
       [0003] The sensors may be used in association with metal making equipment such as lances that discharge combustible or inert gases and/or particulate matter into the metal making vessel during metal heating and refining processes. They may be either intended for repeated use or they may be disposable and expended after a single use. If designed for repeated use, they may be incorporated into the lance structure itself whereby the lance structure serves as protection for the sensor. However, the lance structure must be designed and specifically adapted to accommodate the sensor which results in increased lance development and assembly time and cost. And, since the sensor is internal to the lance, if the sensor needs repair or replacement, the lance must be disassembled, thereby resulting in considerable lance downtime and maintenance costs.  
       [0004] Alternatively, the sensor may be suspended from the lance structure in which case the sensor itself must be fortified in order to avoid damage to the sensor in the hot, caustic and violent atmosphere of the metal making vessel. If suspended from the lance (or from an auxiliary lance or sublance separate from the lance) the sensor must be fortified and the lance (or sublance) must be adapted to accommodate structure for suspending the sensor, both of which result in increased cost. Examples of such lances and sensors may be found in U.S. Pat. Nos. 3,574,598; 3,869,369; 4,106,756 and 4,272,989.  
       [0005] A variety expendable or disposable sensors for metal making applications are marketed by Heraeus Electro-Nite of Houthalen, Belgium and others. As is known, expendable sensors are tethered to suitable hardware, instrumentation and calibration equipment by flexible communications cables. Such sensors, together with their associated hardware, instrumentation and calibration equipment offer a comprehensive control system for the online recording of temperatures and constituent elements such as carbon, oxygen, hydrogen, nitrogen, and aluminum in hot metal and steel.  
       [0006] Expendable sensors may be categorized as sublance sensors and drop sensors. Sublance sensors are suspended by an auxiliary lance or sublance separate from the metal making lance. The presence of a sublance adds additional instrumentality to the metal making vessel which occupies space that might be used for other useful purposes. In addition, a sublance mounted sensor is not an optimal means of sensing characteristics in the metal making vessel occurring closely adjacent the metal making lance.  
       [0007] Drop sensors do not require a sublance for their placement in a metal making vessel and therefore consume less space an instrumentality in operation. However, they are difficult to position at targeted sites within a metal making vessel and cannot be reliably placed and maintained closely adjacent the metal making lance. Consequently, drop sensors, like sublance sensors, are less than desirable apparatus by which to monitor conditions close to the metal making lance.  
       [0008] An advantage exists, therefore, for a system wherein disposable sensor means may be used in conjunction with a conventional metal making lance in order to reliably sense conditions in a steel making vessel close to the metal making lance.  
       SUMMARY OF THE INVENTION  
       [0009] The present invention provides an assembly wherein disposable sensor means may be used in conjunction with conventional a metal making lance with minimal adaptation of the lance&#39;s structure. More particularly, the assembly contemplates the use of disposable sensor means that may be dispensed through a sensor feed tube disposed interiorly or exteriorly of a conventional metal making lance. The sensor means may be selected to detect one or more characteristics of the metal being treated and/or operating conditions of the furnace vessel, especially those in close proximity to the metal making lance.  
       [0010] Other details, objects and advantages of the present invention will become apparent as the following description of the presently preferred embodiments and presently preferred methods of practicing the invention proceeds. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0011] The invention will become more readily apparent from the following description of preferred embodiments shown, by way of example only, in the accompanying drawing wherein:  
     [0012]FIG. 1 is an elevational view of a metal making lance and sensor system according in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] As shown in FIG. 1, the present invention comprises a metal making lance assembly  2  including a barrel  4  and tip  6 . As is known, tip  6  of lance assembly  2  discharges one or more gaseous and/or particulate materials through at least one nozzle at high velocities into a furnace vessel (not shown) in order to melt and refine metal, such as steel, aluminum, copper or alloy contained in the vessel. Tip  6  may discharge the gaseous and/or particulate materials at a distance from the metal being processed. Tip  6  may also be a so-called submergible tip adapted for insertion into a molten bath during metal processing.  
     [0014] According to the invention, lance assembly  2  additionally comprises a sensor feed assembly  8 . In the illustrated embodiment, assembly  8  includes a sensor feed tube  10  affixed to the outer wall of barrel  4  by welding, brazing or the like. It will be understood, however, that sensor feed tube  10  may also be disposed interiorly of the lance barrel  4 . In either case, sensor feed tube  8  is sized to accommodate sliding passage of disposable or expendable sensor means  12  that are operable to detect one or more characteristics of the metal being treated and/or operating conditions within the furnace vessel. Among their advantages, expendable sensors are simple in design, relatively inexpensive and essentially maintenance free. In operation, they are consumed by the hostile environment of the metal making environment as they perform their dedicated sensing function. And, when exhausted, they are easily replaced by new sensors.  
     [0015] According to a presently preferred embodiment, sensor means  12  preferably comprise a plurality of consumable sensors. By way of example, but not limitation, sensor means  12  may detect the temperature of the furnace vessel or the molten metal bath within the vessel and/or the concentration of one or more gases or other constituents within the vessel or in the metal bath. For example, sensor means  12  may be selected so as to detect the temperature of the furnace vessel or, if lance tip  6  is submerged in a molten metal bath (not illustrated), the temperature of the bath. Alternatively, or in addition thereto, sensor means  12  may be selected so as to detect the presence and, preferably, the concentration of one or more chemical constituents in the metal bath, in slag material above the bath or in the furnace vessel itself (also not shown). Representative although not limitative examples of consumable sensor means  12  that would find beneficial use in the present invention in a steelmaking environment may include any of several expendable or consumable immersion and drop sensors marketed by Heraeus Electro-Nite of Houthalen, Belgium or other manufacturers. Such sensors are preferably used in their typical manner in conjunction with unillustrated hardware, instrumentation and calibration equipment marketed by Heraeus Electro-Nite or other manufacturers to provide a comprehensive control system for online recording of temperatures and/or constituent elements in the molten steel bath, slag and/or steel making vessel. It will be understood that, consistent with the present invention, similar sensors and hardware, instrumentation and calibration equipment also marketed by Heraeus Electro-Nite or other manufacturers may be used in aluminum, copper or other metal and metal alloy refining and manufacturing processes.  
     [0016] Optionally, sensor means  12  may include a sampler  14  for collecting a sample of the molten metal bath whereby compositional and other characteristics of the metal may be determined. Suitable sensors with samplers are available from Heraeus Electro-Nite or other manufacturers.  
     [0017] If sensor means  12  is constructed as a plurality of individual consumable sensors, sensor feed assembly  8  further preferably comprises sensor loading means  16  for serially depositing sensors  12  (and their flexible communications cables) into the upper inlet end of sensor feed tube  10 . A presently preferred sensor loading means  16  is a linearly or rotatably movable mechanical, hydraulic, pneumatic, electrical, electromechanical, and semi- or fully-automated magazine loader capable of serially depositing sensors  12  into the inlet of sensor feed tube  10  as sensors are consumed at the lower or outlet end thereof.  
     [0018] Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention as claimed herein.