Device for determining the topography of the burden surface in a shaft furnace

Abstract

Device for determining the topography of the burden surface in a shaft furnace (10) with a radar device (20) scanning the burden surface (18) with an antenna device (22, 35, 37, 43) which is arranged in the region of a furnace cover (13), wherein the antenna device is arranged on a rotation axis (24) inclined at an angle of inclination α with respect to a vertical axis (15) of the shaft furnace and is rotatable about the rotation axis by means of a drive device, characterized in that the antenna device is designed such that a main axis direction H of the radar radiation substantially coincides with the rotation axis and a beam opening angle β of the antenna device forms a radar fan (28) which enables the impact of the burden surface along a profile line p between the vertical axis (15) and a furnace wall (19) of the shaft furnace, wherein the antenna device is designed such is rotatable,that the radar fan (28) formed by the emitted radar radiation of the antenna device impinges on the burden surface along the profile line p and, when the antenna device rotates about the rotation axis by 360°, sweeps over the entire burden surface.

Description

[0001] The invention relates to a device for determining the topography of the burden surface in a shaft furnace with a radar device scanning the burden surface with an antenna device which is arranged in the region of a furnace cover, wherein the antenna device is arranged on an axis of rotation inclined at an angle of inclination α with respect to a vertical axis of the shaft furnace and is rotatable about the axis of rotation by means of a drive device.

[0002] The process in a shaft furnace is largely determined by the structure of the coke and burden layers arranged in the furnace vessel. To form the layers, the furnace is charged with coke and burden through a charging opening located in the furnace roof. A charging device, known in technical terms as a "rotating chute," is located in the charging opening. This device can rotate around the vertical axis of the shaft furnace and has a discharge ramp whose inclination relative to the vertical axis is adjustable. The rotating chute enables the alternating charging of coke and burden layers into the shaft furnace, with the aim of achieving the most precisely defined layers possible to achieve a reproducible blast furnace process.

[0003] To achieve this, it is necessary to determine the surface topography of the topmost layer as accurately as possible before the subsequent layer is added. In this context, radar systems are known to be used to measure surface topography.

[0004] EP 0 291 757 A1 discloses a radar device arranged at the end of a tube lance penetrating the furnace vessel wall below the furnace lid. This device enables the detection of a surface profile of the burden by moving the radar device radially to the center axis of the shaft furnace using the tube lance. To detect further radial surface profiles of the burden, EP 0 291 757 A1 proposes additionally arranging the radar device at the end of the tube lance so that it can pivot about a longitudinal axis and a transverse axis of the tube lance, allowing the surface of the burden to be scanned along a rectangular "crosshair."

[0005] Apart from the fact that the known radar device only enables the detection of essentially linear radial surface profiles and not the detection of the topography of the entire burden surface, the known radar device requires a considerable amount of equipment for its implementation, which requires both the provision of a displaceable tube lance penetrating the vessel wall of the shaft furnace and a two-axis pivoting arrangement of the radar device at the end of the tube lance.

[0006] To avoid such equipment complexity, it is known from WO 2010 / 144936 A1 to arrange a radar device stationary in a furnace cover. The radar device is provided with an antenna device arranged in a plane perpendicular to the vertical axis of the shaft furnace, which antenna device is composed of a plurality of patch antennas arranged in a matrix arrangement. These patch antennas emit radar radiation onto the entire burden surface, thus eliminating the need for a scanning process as known from EP 0 291 757 A1, which requires an axial movement of the antenna device with the corresponding equipment complexity. To enable exposure to all sub-areas of the burden surface, the antenna device known from WO 2010 / 144936 A1 is arranged in the furnace cover on the vertical axis of the shaft furnace.In order to achieve a high angular resolution and to reduce interference from the radar radiation emitted by the large number of patch antennas, a synthetic aperture is formed via a complex control of the patch antennas in such a way that defined patch antennas are operated as transmitting antennas and other defined patch antennas as receiving antennas.

[0007] Apart from the fact that the known radar system requires considerable control effort to generate the synthetic aperture necessary for its operation, the arrangement of the radar system in the kiln cover is associated with significant disadvantages. Firstly, this results in the maximum possible temperature load for the radar system, and in particular for the temperature-sensitive antenna system. Secondly, installing the radar system in a conventionally designed shaft kiln, which has the rotating chute described above for the defined feeding of the burden surface, is not possible because mutual interference would be unavoidable.

[0008] JP H06-11 328 A discloses a device for determining the topography of the burden surface in a shaft furnace. The device has a total of three rotation axes that enable kinematic control of an antenna device such that the inclination of the longitudinal axis of the antenna device is adjusted by pivoting the antenna device about a first rotation axis parallel to the burden surface. A second rotation axis formed by the drive shaft of a drive gear and aligned parallel to the vertical axis of the shaft furnace rotates the antenna device about a third rotation axis formed by a rotating ring, which is also aligned parallel to the vertical axis of the shaft furnace.

[0009] From DE 42 38 704 A1 and JP 2010 17 43 71 A, antenna devices are known which are arranged so as to be pivotable about a rotation axis which extends parallel to the burden surface, i.e. is arranged at right angles to the vertical axis.

[0010] US 2004 01 08 951 A1 shows a “foldable” radar device which is used to measure the level in a tank and is provided with an antenna device which can be pivoted for installation of the radar device.

[0011] Further devices for determining the topography of a burden surface are known from EP 2 202 536 A2, JP 2006-112 966 A and JP 2011-033 619 A.

[0012] The present invention is therefore based on the object of proposing a device of the type mentioned at the outset which enables an accurate recording of the topography of the burden surface and whose installation and operation is possible with the least possible effort.

[0013] To achieve this object, the device according to the invention has the features of claim 1.

[0014] According to the invention, the antenna device is arranged on an axis of rotation inclined at an angle of inclination α with respect to a vertical axis of the shaft furnace and is rotatable about the axis of rotation by means of a drive device, wherein the antenna device is designed such that a main axis direction H of the radar radiation substantially coincides with the axis of rotation and a beam opening angle β of the antenna device forms a radar fan which enables the impact on the burden surface along a profile line p between a vertical axis and a furnace wall of the shaft furnace, wherein the antenna device is rotatable such that the radar fan formed by the emitted radar radiation of the antenna device impinges on the burden surface along the profile line p and sweeps over the entire burden surface when the antenna device rotates 360° about the axis of rotation.

[0015] The device according to the invention thus enables, on the one hand, due to its arrangement on the rotational axis inclined relative to the vertical axis of the shaft furnace, an arrangement that does not collide with a charging device arranged in the furnace cover, preferably in the form of a rotating chute. On the other hand, due to the arrangement of the antenna device on the rotational axis inclined relative to the vertical axis, the temperature load on the antenna device is fundamentally reduced compared to an arrangement on the vertical axis. Furthermore, the inventive superposition of a radar fan emitted by the antenna device with a rotational movement of the antenna device makes it possible for the antenna device to not necessarily be operated with a control to form a synthetic aperture in order to achieve the desired high surface resolution.Rather, the achievable resolution depends, among other things, on the pulse rate of the radar radiation and the rotation speed with which the antenna device rotates around the rotation axis.

[0016] Overall, the device according to the invention enables the burden surface to be detected with high resolution and with comparatively low control and equipment costs, since only the formation of a rotation axis for the rotation of the antenna device is necessary.

[0017] This also makes it possible to subsequently integrate the device according to the invention into a conventionally designed shaft furnace which has a charging device in its furnace cover, preferably designed as a rotating chute.

[0018] In a preferred embodiment, the angle of inclination α of the rotation axis relative to the vertical axis is between 20° and 60°.

[0019] A particularly simple design of the device is possible if the antenna device is arranged in an antenna plane oriented perpendicular to the axis of rotation.

[0020] If it should prove insufficient to cover the entire bulk material or burden surface with only one antenna, particularly due to insufficient quality or an insufficient aperture angle of the antenna device used, it is also possible to construct the antenna device modularly from at least two antenna modules which, by superimposing their beam aperture angles, enable the formation of a radar fan with the desired width.

[0021] The use of a plurality of antenna modules for the antenna device also allows a reduction in the angle of rotation required to cover the entire surface.

[0022] The antenna modules can be arranged in a common antenna plane.

[0023] Preferred embodiments of the device are explained in more detail below with reference to the drawings. They show: Fig. 1 shows a shaft furnace in sectional view with a radar device arranged in the upper part of a furnace vessel in a vessel wall in a first embodiment; Fig. 2 which in Fig. 1 shown radar device in a sectional view according to section line II-II in Fig. 1; Fig. 3 an alternative embodiment of the Fig. 2 radar device; Fig. 4 shows a further embodiment of a radar device arranged in the vessel wall, not according to the invention; Fig. 5 a sectional view according to section line VV of the Fig. 4 shown radar device; Fig. 6 an alternative embodiment of the Fig. Radar device shown in Figure 5.

[0024] Fig. 1 shows a shaft furnace 10, which essentially consists of a furnace bottom part 11, a furnace top part 12 and a furnace cover 13, into which a charging device, designed here as a rotating chute 14, is integrated, which can be pivoted about a vertical axis 15, so that a charging ramp 17 adjoining a hopper opening 16 of the rotating chute 14, which is adjustable in inclination relative to the vertical axis 15, can be positioned in a defined manner.

[0025] The rotating chute 14 serves for the alternating feeding of the shaft furnace 10 with Fig. 1 Coke and burden layers, not shown in detail, with the aim of achieving layers as precisely defined as possible to achieve a reproducible blast furnace process. To achieve this, it is necessary to determine the surface topography of the topmost layer as precisely as possible before adding the subsequent layer.

[0026] To record a Fig. 1, a radar device 20 is arranged in the region of the furnace lid 13 above the burden surface 18 in a furnace wall 19 of the furnace upper part 12, with a housing 21 of the radar device 20 penetrating the furnace wall 19. Within the housing 21 is an antenna device 22, which is arranged on an antenna carrier 23 which is rotatable about a rotation axis 24 and can be driven by a drive device not shown in detail here via a carrier shaft 25.

[0027] The antenna device 22, which is also in Fig. 2, is located in an antenna plane 26 arranged perpendicular to the axis of rotation 24 and is shielded from the furnace atmosphere by a protective screen 27 permeable to radar radiation. In the illustrated embodiment, the axis of rotation 24 is inclined at an angle α of approximately 30 degrees with respect to the vertical axis 15 and intersects the vertical axis 15 approximately at an intersection point S of the vertical axis 15 with the burden surface 18. The antenna device 22 is designed such that a main axis direction H of the radar radiation essentially coincides with the axis of rotation 24 and a beam opening angle β of the antenna device 22 is sufficiently large to form a radar fan 28 which enables the impact on the burden surface 18 along a profile line p between the vertical axis 15 and the furnace wall 19 of the shaft furnace 10.In the present case, the radar fan 28 is designed with edge beams 29, 30, wherein the edge beam 29 intersects the burden surface 18 at a surface point O in an installation half 31 of the shaft furnace 10, in which the radar device 20 is located, at a distance a from the furnace wall 19, and the edge beam 30 intersects the furnace wall 19 at a wall point W on a furnace half 32 opposite the installation half 31, so that in the illustrated embodiment the profile line p of the burden surface 18 acted upon by the radar fan 28 extends from the surface point O to the furnace wall 19. When the antenna device 22 rotates 360° about the rotation axis 24, the radar fan 28 sweeps over the entire burden surface 18.

[0028] Fig. 3 shows an antenna device 35 which consists of several antenna modules 36 arranged in the same antenna plane 26.

[0029] Fig. Figure 4 shows the radar device 20 with an antenna device 37, which has two antenna modules 38, 39, each arranged in an antenna plane 40, 41. The antenna planes 40, 41 are each inclined at an angle γ to the rotation axis 24, so that the main axis directions H1, H2 of the antenna modules 38, 39 intersect the burden surface 18 at different intersection points S1 and S2. Both antenna modules 38, 39 each have an aperture angle β1 and β2, which in the present case are identical. Both aperture angles β1, β2 of the antenna modules 38, 39 form, in their superposition, a radar fan 28, which corresponds to the Fig. 1 corresponds to the radar fan 28 shown.

[0030] Deviating from the representation in Fig. 4, it is of course also possible that the antenna planes 40 of the antenna modules 38, 39 have different angles γ relative to the rotation axis 24. It is also possible, as in Fig. 6 shows that three or more antenna modules 42, 43, 44 together form an antenna device 45, wherein the antenna planes in which the antenna modules 42 to 44 are located can have a matching angle relative to the rotation axis 24 or also different angles relative to the rotation axis 24.

[0031] Regardless of the above-mentioned Fig. 1 to 6, it becomes clear that the radar device designed according to the invention enables an arrangement or integration into a shaft furnace 10 without there being a risk of collision with a charging device, designed here as a rotating chute 14, arranged in the furnace cover 13.

Claims

[1] Device for determining the topography of the burden surface in a shaft furnace (10) with a radar device (20) scanning the burden surface (18) with an antenna device (22, 35, 37, 43) which is arranged in the region of a furnace cover (13), wherein the antenna device is arranged on an axis of rotation (24) inclined at an angle of inclination α with respect to a vertical axis (15) of the shaft furnace and is rotatable about the axis of rotation by means of a drive device, characterized bythat the antenna device is designed such that a main axis direction H of the radar radiation essentially coincides with the axis of rotation and a beam opening angle β of the antenna device forms a radar fan (28) which enables the impingement on the burden surface along a profile line p between the vertical axis (15) and a furnace wall (19) of the shaft furnace, wherein the antenna device is rotatable such that the radar fan (28) formed by the emitted radar radiation of the antenna device impinges on the burden surface along the profile line p and sweeps over the entire burden surface when the antenna device rotates about the axis of rotation by 360°. [2] Device according to claim 1, characterized by that the angle of inclination α of the rotation axis (24) relative to the vertical axis (15) is between 20° and 60°. [3] Device according to claim 1 or 2, characterized bythat the antenna device (22) extends in an antenna plane (26) oriented perpendicular to the axis of rotation (24). [4] Device according to one of the preceding claims, characterized by that the antenna device (35, 37, 43) has at least two antenna modules (36, 38, 39, 42). [5] Device according to claim 4, characterized by that the antenna modules (36) are arranged in a common antenna plane (26).

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