Mill Ladle Refractory Monitoring
Steel mill ladles have limited lives. As their refractory linings wear or develop breaks due to shock, the outer part of a ladle can be exposed to excessive temperatures. If not caught in time, the result can be ladle disintegration and a molten metal breakout, threatening the lives of workers and destroying equipment. FLIR thermal imaging camera systems are used to monitor ladles in real time and warn of a breakout before it happens, saving hundreds of thousands of dollars by preventing injuries, equipment damage, and production downtime.
Fortunately, thermal imaging cameras can detect hot spots on the ladle that warn of a failure far sooner than a visual inspection. This allows the ladle to be taken out of service in a timely manner and scheduled for relining exactly at the right time and at the optimum replacement cost.
The IR Monitor software can then compare each image frame from a camera to the image templates stored in PC memory. This gantry crane operator does not have to stop the crane at any particular location to capture images and the production can continue smoothly. When there is a match between the template and the corresponding portion of a camera’s FOV (i.e. one or the ROIs), temperatures are calculated. If a temperature exceeds the ladle’s predefined parameters, an alarm is triggered. The exact parameters temperatures for alarms can be adjusted easily, based on mill experience.
Alarmingly high temperatures
The alarm could be just a warning if the
temperature isn’t too high, and movement of the ladle to the converter
mill can continue. The operator can then compare the warning temperature
to a trend analysis done by the software to determine if the ladle can
remain in service for another pour.
If the ladle temperature is above a critical level, however, an emergency alarm will be triggered which will immediately stop the gantry crane movement. In addition, alarm messages and images can be sent to a mill manager’s office via Ethernet, email, or ftp.
This application is not just useful for mill ladles. The same system can also be used for torpedo car monitoring. The objectives are the same, and the major system difference is in the mounting of the thermal imaging cameras. Typically, cameras are placed on both sides of the rail track that along which the torpedo cars are transported to the converter mill.
The torpedo cars are preheated before the
molten metal is poured in to prevent it from hardening. Thermal imaging
cameras can also be used to optimize this preheating process by
minimizing the duration and the energy consumption while ensuring that
the refractory is sufficiently heated to prevent the molten metal from
hardening. A thermal imaging camera can see through the preheat flame
and monitor the refractory temperature from a safe distance. This
eliminates the use of thermocouples that are less accurate and burn out
The schematic illustration on this page depicts
a typical setup for an automated Mill Ladle Refractory Monitoring
System using the FLIR A310 Camera. Although the analog video and digital
I/O outputs from this camera allow it to operate as a standalone smart
sensor, most steel mill applications use its digital data stream, sent
over Ethernet lines, in computer controlled automation systems. The
A310’s Ethernet interface can supply the camera’s video signal to
virtually anywhere and facilitates monitoring from multiple locations.
FLIR’s IR Monitor software is used to control all camera functions, collect temperature data, display thermal images, and perform data analysis. The operator’s display is the primary interface for alarm functions.
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