The disclosure generally relates to cooling plates for metallurgical furnaces, namely blast furnaces, and in particular to cooling plates with means for detecting body wear after abrasion of the refractory wall.
Cooling plates for metallurgical furnaces, also called “staves”, are well known in the art. They are used to cover the inner wall of the outer shell of the metallurgical furnace, as e.g. a blast furnace or electric arc furnace, to provide:
The disclosure provides an alternative and reliable way of monitoring the wear status of cooling plates.
A cooling plate for a metallurgical furnace is provided comprising a body with a front face and an opposite rear face, the body having at least one coolant channel therein. In use, the front face, which preferably comprises alternating ribs and grooves, is turned towards the furnace interior.
It shall be appreciated that the cooling plate is provided with wear detection means, which comprise a plurality of closed pressure chambers distributed at different locations within the body and positioned at predetermined depths below the front face of the body. A pressure sensor is associated with each pressure chamber in order to detect a deviation from a reference pressure when a pressure chamber becomes open due to wear out of the body portion.
The disclosure thus proposes a way of detecting the wear of cooling plates relying on the physical principle of pressure variation, which is easy and relatively inexpensive to monitor. Furthermore, the network of closed pressure chambers embedded in the plate body allows the concomitant monitoring of the wear at several locations and to possibly distinguish several wear statuses (or wear levels), depending on the number of closed pressure chambers and their distance to the surface. Hence, the disclosure allows an enhanced monitoring of a cooling plate where one can know the wear status of the cooling plate at several body regions, and even can distinguish between different wear conditions in a same region.
In a preferred embodiment, the pressure chambers are formed as blind bores drilled from the rear face of the body, and closed by a sealingly mounted plug. Each pressure sensor may then be supported by its respective plug, and the connecting wire of the pressure sensor sealingly passes through the plug towards the exterior. Suitable sensors are e.g. of the piezoelectric type. For ease of implementation, the pressure chambers, respectively the blind bores, may be formed as elongate hollow chambers extending substantially perpendicularly to the front face of the body. The blind bores can, e.g., have a diameter of less than 5 mm, preferably in-between 1 and 3 mm.
Advantageously, the pressure chambers are distributed at the different locations by groups of at least two pressure chambers, each pressure chamber within the group being positioned at a different predetermined depth below the front face of said body. In particular, within each group, a pressure chamber may be positioned underneath a rib and a pressure chamber positioned underneath a groove. In doing so, one can monitor several regions of a cooling plate and within each region even distinguish between different wear levels. For example, the groups of pressure chambers may be located in the upper, bottom and central sections of the body, preferably using 2 or 3 groups per section.
In practice, the pressure chambers are manufactured as closed and sealed chambers containing a given fluid at a reference pressure, selected so that in use the reference pressure therein is different from the blast furnace operating pressures. For ease of implementation, the fluid inside the pressure chambers is air, although other gases (especially inert gases) could in principle be used. In principle the fluid in the pressure chambers may be a liquid, e.g. water, but again gases and in particular air are preferred, to avoid releasing water inside the furnace even in small amounts. The reference pressure for gas may be selected from: vacuum pressure, a pressure lower than the furnace operating pressure, a pressure higher than the furnace operating pressure. Supposing a typical blast furnace operating pressure in the range of 2 to 3 bars, the reference pressure (measured at ambient temperature) may for example be around 1 bar (atmospheric pressure), or about 4-5 bars, or higher.
According to another aspect, the invention concerns a blast furnace comprising a shell lined with cooling plates as described above, and comprising a control system which is configured to: receive pressure signals from each of the pressure sensors of the pressure chambers in the cooling plates; to detect pressure deviation from the reference pressure at the pressure sensors; and to display a mapping of the wear status of the cooling plate lining based on the information from the pressure signals and the known location of the cooling plates in the blast furnace.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
A preferred embodiment of the present cooling plate 10 is schematically illustrated in
As is known in the art, the front face 18 of body 12 advantageously has a structured surface, in particular with alternating ribs 22 and grooves 24. When the cooling plate 10 is mounted in the furnace, the grooves 24 and lamellar ribs 22 are generally arranged horizontally in order to provide an anchoring means for a refractory brick lining (not shown).
As it is known, during the course of operation of a blast furnace or similar, the refractory brick lining erodes due to the descending burden material, leading to the fact that the cooling plates are unprotected and have to face the harsh environment inside the blast furnace.
As a result, abrasion of the cooling plates occurs too and it is desirable to know the wear status of the cooling plates.
It shall be appreciate that the present cooling plate 10 is equipped with wear detection means, as will now be explained.
The present wear detection means comprise a plurality of closed pressure chambers 26, 28 distributed at different locations in the body 12 and positioned at predetermined depths below the front face 18 of the body 12. The closed pressure chambers 26, 28 are manufactured to be set at an internal reference pressure (normally different from the blast furnace operating pressure), and a pressure sensor 30 is associated with each pressure chamber 26, 28. When the body 12 will have eroded down to the depth of a closed pressure chamber, the latter will become open and the pressure will equilibrate with the operating pressure of the blast furnace. In monitoring the pressure in the closed pressure chamber 26, 28 one can thus detect the moment the closed pressure chamber opens, which will be indicated by a deviation from the initial reference pressure. In practice, the closed pressure chambers 26, 28 may be formed as blind bores, drilled from the rear face 20 of the cooling plate. These holes are drilled substantially perpendicularly to the front face 18 of the cooling plate 10 as it can be seen from
As indicated above, the monitoring principle is based on a pressure deviation from a reference pressure. Accordingly, each pressure chamber 26, 28 is initially set to a reference gas pressure, which is different from the usual blast furnace operating pressures. In that way a significant change in pressure can be measured when a closed pressure chamber becomes open due to wear out of the body portion initially separating the inner end of the pressure chamber from the front edge of the panel. The pressure in the each pressure chamber 26, 28 may thus be set to a reference pressure that is either lower, or higher than the blast furnace operating pressures, or may even be set to a vacuum pressure.
In
For example, the pressure chambers may be distributed by groups of at least two pressure chambers, each pressure chamber within the group being positioned at a different predetermined depth below the front face of said body. Turning to
The inner extremity of pressure chamber 28 is located at distance D1 below the surface of the rib, whereas chamber 26 is located at distance D2 below the respective groove, which may also be referred to as distance D′2 when comparing to the neighboring rib 22.
The so-called “depth” of a pressure chamber thus corresponds to the distance from the inner end of the pressure chamber in the body to the front face 18 of the cooling plate here D1 and D′2 when taking as reference the front side at the level of non-used ribs 22 in a new cooling plate.
the detection of a pressure variation in pressure chambers 28 will thus imply that the rib thickness has decreased by more than D1. The detection of a pressure variation in pressure chamber 26 will imply that the thickness of body at groove 24 has diminished by more than D′2, or that the wear level at the groove 22 is more than D2 (depending on the reference).
The configuration shown in the Figures thus allows monitoring 9 different location/regions of the cooling plate 10: the cooling plate is divided into upper, bottom and central sections, each of them being subdivided into left, right and center portions.
Furthermore, for each region, one can monitor the wear of a rib and of a groove.
Number | Date | Country | Kind |
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92 515 | Aug 2014 | LU | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2015/068301 | 8/7/2015 | WO | 00 |