DAMAGE DETECTION SYSTEM AND METHOD OF USE

Abstract

The present invention relates to damage detection systems for refractory linings for molten metal vessels, comprising an electrically conductive grid disposed underneath the surface of the refractory lining closest to a molten metal when in use, one or more electrically conductive electrodes disposed in contact with the molten metal when in use and an electrical power source, wherein the electrically conductive metallic grid and the one or more electrically conductive electrodes are electrically connected to each other, such as to form an open electrical circuit powered by the said electrical power source, and a detected closure of the said electrical circuit during normal use of the molten metal vessel indicates that the said refractory lining is damaged, or the presence of a molten metal during normal operation of the vessel closes the said electrical circuit in case the refractory lining is damaged. The present invention relates to a method for detecting damage in a refractory lining during use, and the use of a damage detection system according to the invention.

Claims

1. A damage detection system for refractory linings for molten metal vessels, comprising: an electrically conductive grid disposed underneath the surface of the refractory lining closest to a molten metal when in use; one or more electrically conductive electrodes disposed in contact with the molten metal when in use; and an electrical power source; wherein the said electrically conductive metallic grid and the said one or more electrically conductive electrodes are electrically connected to each other, such as to form an open electrical circuit powered by the said electrical power source, and wherein a detected closure of the said electrical circuit during normal use of the molten metal vessel indicates that the said refractory lining is damaged.

2. A damage detection system for refractory linings for molten metal vessels, comprising: an electrically conductive grid disposed underneath the surface of the refractory lining closest to molten metal when in use; one or more electrically conductive electrodes disposed in contact with the molten metal when in use; and an electrical power source; wherein the said electrically conductive metallic grid and the said one or more electrically conductive electrodes are electrically connected to each other, such as to form an open electrical circuit powered by the said electrical power source, and wherein the presence of a molten metal during normal operation of the vessel closes the said electrical circuit in case the refractory lining is damaged.

3. A damage detection system according to claim 1, wherein the said refractory lining is a monolithic refractory lining.

4. A damage detection system according to claim 1, wherein the said electrical power source comprises a battery.

5. A damage detection system according to claim 4, wherein the said electrical power source comprises two batteries connected in parallel.

6. A damage detection system according to claim 1, wherein the closure of the said electrical circuit leads to the triggering of an alarm.

7. A damage detection system according to claim 5, wherein the closure of the said electrical circuit leads to the triggering of an alarm and wherein each of the batteries connected in parallel is associated with a separate alarm.

8. A damage detection system according to claim 1, further comprising one or more indicator circuits triggered when the said electrical power source is in a normal functioning mode.

9. A damage detection system according to claim 1, further comprising a switch artificially short-circuiting the said open electrical circuit.

10. A damage detection system according to claim 1, wherein the said electrically conductive electrodes are electrically connected to a steel shell of the said molten metal vessel.

11. A damage detection system according to claim 1, further comprising a secondary electrical connection between the said electrically conductive grid and the electrical power source, which wherein the secondary electrical connection may be interrupted by a switch.

12. A damage detection system according to claim 1, further comprising a secondary circuit between all of the said one or more electrically conductive electrodes and the electrical power source, which may be interrupted by a switch.

13. A damage detection system according to claim 1, installed within a refractory lining installed in a molten metal vessel or vessel spout, a ladle, a tundish, a reaction chamber or a trough, or in a cupola hearth or a siphon, a blast furnace, or a main, secondary or tilting runner.

14. A method for detecting damage in a refractory lining during use, comprising installing a damage detection system according to claim 1 and detecting closure of the electrical circuit contained therein.

15. (canceled)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention according to the appended claims provides a system for detecting any damage in a refractory lining for a molten metal vessel. The system is simple to install and use, and allows for direct online monitoring of the integrity of a refractory lining during its operation with molten metal. The principle of the system lies in that an open electrical circuit is installed, wherein a power source has one pole connected to an electrically conductive grid, which is disposed underneath the surface of the refractory lining to be monitored, and a second pole connected to an electrode which will be in contact with the molten metal during normal operation of the molten metal vessel. Provided that the monitored refractory lining is intact, the open electrical circuit will not be activated. If however there is damage on the monitored refractory lining, this will allow the molten metal during operation to come into electrically conductive contact with the grid, thereby closing the electrical circuit and causing a current to be established in the circuit. If an alarm is connected in the circuit, then an operator may be made aware of the damage in the refractory lining.

[0028] According to the present invention, the closure of the open electrical circuit indicates that the refractory lining is damaged to such an extent that molten metal penetrates into the lining. According to the requirements of the operator, the electrically conductive grid may be installed at such a depth relative to the surface of the refractory lining normally in contact with the molten metal, at which impediment to the safety or economic viability of the refractory lining is considered likely. Accordingly, the sensitivity of the system according to the present invention may be adapted according to the operator's requirements. For example, in particular in the case of non-monolithic refractory linings made up of bricks and/or plates or the like, the electrically conductive grid may be placed underneath the said bricks and/or plates, such that the system is triggered only when molten metal penetrates underneath a chosen layer of refractory bricks or plates. In another embodiment, the electrically conductive grid may be placed directly onto the inner side of an external wall of the vessel, or the external wall of the vessel may replace the electrically conductive grid, provided that the inner wall of the vessel itself is electrically conductive.

[0029] An advantage of the system according to the present invention lies in that the damage control of a refractory lining is carried out during operation of the refractory lining within a molten metal vessel. Therefore regular checks in between operations of the molten metal vessel are no longer required, and down-time can be reduced. Furthermore, the system is adaptable to the specific requirements of the operator, by placing the electrically conductive grid at the required depth. In the case of cast monolithic refractory linings, the electrically conductive grid may be placed at any depth. In the case of refractory linings assembled from bricks and/or plates, the electrically conductive grid needs to be placed between or underneath a layer as required. It is possible to place the grid under the entire surface, or substantially the entire surface of the monitored refractory lining. Alternatively, one or several grids may be placed only at specific areas which are considered to be most at risk from damage. Either alternative is part of the present invention.

[0030] The one or more electrically conductive electrodes employed in the present invention are placed such that they are in contact with the molten metal during normal operation of the vessel. For example, one electrode may penetrate the wall of the vessel at a level below the level to which the vessel is normally filled during operation. Alternatively, an electrode may protrude through a base of the said vessel such that it is in contact with the molten metal poured into the base of the vessel. This leads to an activation of the electrode at the start of pouring molten metal into the vessel. Alternatively, an electrode may be placed penetrating into the molten metal vessel through a large opening at the top of the vessel. For example, an electrode may only be introduced through a top opening after a vessel has been filled with molten metal, thereby only monitoring damage at a specific time during the operation. In such a case, an electrode may be removed after testing.

[0031] The power source employed in the present invention may be a battery, such as for example a standard 12V battery. Alternatively, the system may be powered by other power sources, such as for example mains electricity (AC), accumulators (DC), solar panels, or any other power source known to the skilled person in the art. Several power sources may be installed in parallel, in order to allow additional reliability of the system in case one power source is exhausted or out of order. For example two batteries may be installed in parallel, or a battery and a mains connection may be installed in parallel, whereas either of the power sources may be functioning as a back-up for the other power source.

[0032] When the electrical circuit of the damage detection system of the present invention is closed, normally by the infiltration of the refractory lining with molten metal, bringing into contact the electrically conductive grid with the electrode, an alarm is normally triggered. The alarm may be an audible alarm such as a horn, a beep, a whistle, a bell or the like. This draws the operator's attention to the fact that the refractory lining of the molten metal vessel may be damaged, and allow them to take adequate measures. The alarm may alternatively be a visible alarm, such as a flashing light, an LED, a moving object or the like, also drawing an operator's attention. The alarm may be a combination of several visible and/or audible signals. If several power sources are employed in parallel, each power source may trigger a separate alarm, or, alternatively, each power source may trigger several alarms.

[0033] Various control or indicator circuits may be integrated into the damage detection system according to the present invention in order to monitor the activity of the damage control system.

[0034] For example, an indicator circuit may be installed, which is triggered when the electrical power source is in normal functioning mode. This may for example be a circuit directly linking the pole of the power source connected to the electrically conductive grid to the pole of the power source linked to the one or more electrodes, via an indicator. The indicator may, for example, be a light source such as an LED. This control LED will show that an electrical current is flowing in the indicator circuit and that the power source is in functioning mode. The indicator circuit may further comprise a switch to turn on and off the indicator circuit control signal.

[0035] A further indicator circuit comprising a switch may be installed to provide an optional short-cut to the main detection circuit. In that case, the power source provides power to the alarm, if installed, when the switch is triggered, without actual damage to the refractory lining. This allows the operator to control the functioning of the alarm.

[0036] Further indicator circuits are envisaged to connect the electrically conductive grid or the one or more electrodes to a secondary power source, with a switch, in order to check the integrity of the connections of the respective parts to the main power source of the damage detection system.

[0037] A method of detecting damage in a refractory lining of a molten metal vessel during operation, and the use of a damage detection system according to the present invention also form part of the present invention.

[0038] It should be noted that the present invention may comprise any combination of the features and/or limitations referred to herein, except for combinations of such features which are mutually exclusive. The foregoing description is directed to particular embodiments of the present invention for the purpose of illustrating it. It will be apparent, however, to one skilled in the art, that many modifications and variations to the embodiments described herein are possible. All such modifications and variations are intended to be within the scope of the present invention, as defined in the appended claims.