Smelting furnace with height detection system

Abstract

A furnace 10 includes a vessel 12 having a central axis extending between a top and a bottom. The container accommodates a body of material 20 having an upper surface 24, the upper surface 24 having an upper height lu. The furnace comprises a non-contact sensor 30.1 for sensing a distance 32 between the reference point and a location on the upper surface. The non-contact sensor includes an electromagnetic signal transceiver 36, 38, an antenna 40 for transmitting a signal towards the upper surface and receiving a reflection of the signal, and a signal conduit 46 extending between the transceiver and the antenna. The transceiver is located at one of the following positions: a) a level lower than the upper height lu, b) a level higher than the upper height lu and beyond the first line 39, the first line 39 being spaced from the layer on the line 41 by a distance d0gt; 0, the line 41 is perpendicular to the central axis.

Description

Technical Field

[0001] The present invention relates to a furnace, and more particularly to an electric arc furnace having a feed material height detection system. Background Art

[0002] In EP2564141B1, a furnace is disclosed, which includes a bottom, at least one side wall and a top, which together form a furnace container to accommodate materials processed in the furnace. The furnace includes at least one non-contact sensor for determining the position or height of the material in the furnace relative to the sensor. Based on the height of the material in the furnace, one or more operating parameters of the furnace can be modified, including, for example, the rate at which additional material is introduced into the container and the rate at which material is removed from the container. As shown in Figure 1 (also Figure 1 of EP2564141B1), the sensor 110 is located directly above the raw material layer 120. The sensor generally includes at least one transmitter located in a fixed position directly above the raw material layer and at least one receiver located directly above the raw material layer. The sensor 110 can be arranged in the top 106, or below the top, or above the top, but in all cases directly above the raw material layer 120. In these cases, a special housing or protective cover 134 is provided at least partially around each non-contact sensor 110 to electromagnetically shield the non-contact sensor from electromagnetic interference ("EMI") present between the non-contact sensor 110 and the raw material layer 120. In at least some embodiments, the EMI protective cover 134 includes a thermal radiation protective cover 136 at its bottom end facing the layer, which is in the form of a replaceable box containing a fire-resistant cloth.

[0003] The above configuration and arrangement of at least one non-contact sensor is not suitable for at least some applications because it may be too complex to commission and / or maintain and service. It may also be too exposed to the adverse furnace environment, too bulky and too expensive. Summary of the invention

[0004] It is therefore an object of the present invention to provide an electric melting furnace with which the applicant believes that the above disadvantages may be at least alleviated or which may provide a useful alternative to known electric melting furnaces.

[0005] According to the present invention, there is provided an electric melting furnace, comprising:

[0006] at least one electrode;

[0007] A container comprising a bottom, at least one side wall and a top region including a top, the container holding a body of material to be processed, the container having a central axis extending between the top and the bottom, the body of material comprising at least one layer having an upper surface having an upper height (lu ) and the lower height (l l ), the at least one electrode extending through the top into the container; and

[0008] at least one non-contact sensor for sensing the distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transmitter, an electromagnetic signal receiver, an electromagnetic signal transmitter facing the upper surface, the transmitter being located at a certain distance above the upper surface in the top area of ​​the furnace, a collector for reflecting the signal transmitted from the upper surface, and a signal conduit located at at least one of the following: a) between the transmitter and the transmitter, b) between the receiver and the collector, and wherein at least one of the transmitter and the receiver is located at one of the following positions outside the container: a) below the height above the upper surface (l u ) horizontal plane; b) a height above the upper surface (l u ) and exceeds the horizontal plane of the first line, the first line is spaced apart from the layer on the second line by a distance d0>0, the second line is perpendicular to the central axis, and the first line extends parallel to the central axis.

[0009] The top region includes the top itself and the regions immediately above and below the top, respectively.

[0010] The furnace may be an electric arc furnace.

[0011] The furnace may be a metallurgical furnace.

[0012] This layer may be the top layer of the feedstock.

[0013] At least one contactless sensor may be coupled to the controller for generating data related to the sensed distance.

[0014] In some embodiments, the furnace may include a plurality of non-contact sensors connected to a controller, each of the non-contact sensors being used to sense a respective distance between a respective reference point and a corresponding one of a plurality of dispersed locations on the upper surface, the controller being operable to generate profile data associated with the upper surface from the respective sensed distances.

[0015] In some embodiments, the transmitter and receiver may be located at a level below the upper height of the upper surface.

[0016] The transmitter and receiver may be located at a level between an upper elevation and a lower elevation of the upper surface.

[0017] The transmitter and receiver may be located adjacent an exterior surface of at least one side wall of the container.

[0018] Alternatively, the transmitter and receiver may be located at a distance from the container.

[0019] In other embodiments, the transmitter and receiver may be located at a level higher than the upper elevation of the upper surface.

[0020] The at least one non-contact sensor may include any suitable type of sensor, including, for example, a laser sensor, an automatic detection sensor, an acoustic sensor, an optical sensor (including digital image processing or optical sensing), a muon particle sensor, a pulsed or frequency modulated electromagnetic sensor, an ultrasonic sensor, a yo-yo sensor, but preferably a radar sensor.

[0021] The radar sensor may include a microwave radar transceiver device.

[0022] The transmitter and collector may be combined in any suitable antenna, such as a horn antenna.

[0023] A waveguide can connect the transceiver device to the antenna.

[0024] The furnace may include a material supply arrangement located at a feedstock port in the top, the material supply arrangement may include a box defining a feedstock inlet in a top wall of the box and a feedstock outlet in a bottom wall of the box, the inlet being linearly offset relative to the outlet, and the emitter and collector being positioned in line with the outlet to have a direct line of sight through the outlet.

[0025] The furnace may have any suitable shape including rectangular, square, and circular to name a few.

[0026] According to another aspect of the present invention, there is provided an electric melting furnace, comprising:

[0027] at least one electrode;

[0028] a container including a bottom, at least one side wall, and a top region including a top, the container holding a body of material to be processed, the container having a central axis extending between the top and the bottom, the body of material including at least one layer having an upper surface, the at least one electrode extending through the top into the container; and

[0029] At least one non-contact sensor for sensing the distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transceiver device, an antenna located a certain distance above the upper surface in the top area of ​​the furnace, and a signal conduit extending between the electromagnetic signal transceiver device and the antenna, wherein the transceiver device is located at a predetermined position outside the container, at which predetermined position, at least one of the container and the distance attenuates electromagnetic interference (EMI) inside the container to such an extent that an EMI protective cover of the transceiver device is omitted except for the original manufacturer's housing of the transceiver device.

[0030] According to yet another aspect of the present invention, there is provided a method of operating an electric melting furnace, the electric melting furnace comprising a container, the container comprising a bottom, at least one side wall and a top region including a top, the container containing a body of material to be processed, the body of material comprising at least one layer having an upper surface; at least one electrode extending through the top into the container; and at least one non-contact sensor for sensing a distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transceiver device, an antenna, the antenna being located at a distance above the upper surface in the top region of the furnace, and a signal conduit extending between the electromagnetic signal transceiver device and the antenna, the method comprising:

[0031] positioning the transceiver device outside the container;

[0032] The signal conduit and at least one of the container and the distance to the transceiver device are used to attenuate electromagnetic interference (EMI) present inside the container to such an extent that no EMI protective cover is provided for the transceiver device at the transceiver device, except for the original manufacturer's housing of the transceiver device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

[0034] FIG1 is a schematic diagram of a prior art metallurgical furnace;

[0035] Figure 2 is a partial cross-sectional schematic diagram of a first exemplary embodiment of an electric melting furnace;

[0036] Figure 3 is a similar view of a second example embodiment of a furnace;

[0037] Figure 4 is yet another similar view of a third example embodiment of a furnace; and

[0038] Figure 5is a schematic diagram of a material feed assembly for a furnace, the feed assembly including or housing an antenna. DETAILED DESCRIPTION

[0039] exist Figures 2 to 4 In the present invention, a first exemplary embodiment of an electric melting furnace is generally indicated by the reference numeral 10 .

[0040] The electric furnace 10 includes a container 12 including a bottom 14, at least one side wall 16, and a top 18 located in the top region of the furnace. The container has a central axis 19 extending between the top and the bottom. The container defines a chamber 21 containing a body 20 of material to be processed. At least one electrode 23 extends through the top to the body. The body includes at least one layer, such as a top layer 22 of raw material having an upper surface 24. The upper surface has an upper height l u and the lower height l l . The furnace 10 also includes at least one non-contact sensor 30.1 and 30.2 for sensing a distance 32 between a reference point (e.g., point 34) and a position on the upper surface 24. The at least one non-contact sensor 30.1 includes an electromagnetic signal transmitter 36, an electromagnetic signal receiver 38, a transmitter 40 of an electromagnetic signal 42 toward the upper surface 24, the transmitter being located at a certain distance above the upper surface, and a collector 40 for reflecting the signal 44 emitted from the upper surface. The signal conduit 46 extends at least one of the following locations: a) between the transmitter 36 and the transmitter 40, b) between the receiver 38 and the collector 40. At least one of the transmitter 36 and the receiver 38 is located at one of the following locations: a) below a height l above the upper surface 24. u The horizontal plane (such as Figure 2 and 3 and b) a height l above the upper surface 24 u The horizontal plane of the first line 39 exceeds the first line 39, the first line 39 is spaced apart from the layer 22 on the second line 41 by a distance d0>0, the second line 41 is perpendicular to the central axis, and the first line 39 extends parallel to the central axis (such as Figure 4 shown).

[0041] refer to Figures 2 to 4 At least one contactless sensor 30 . 1 , 30 . 2 is connected to a controller 48 for generating data related to the sensing distance 32 .

[0042] At least one feed port 49 for feedstock is defined in the top 18. A feed chute (not shown) may be provided in communication with the feed port 49. Figure 5 As described in more detail, in some embodiments, a feed assembly or dead zone 70 may be disposed above or within the top portion 18 .

[0043] The material body 20 includes a charge, which includes a molten metal body 50, a slag layer 52 on the molten metal body, and a raw material layer 22 on the slag layer. It should be understood that the upper surface 24 extending between the side walls of the container has a lower height l l and the upper height l u It will also be appreciated that the profile does not remain static, but rather is dynamic and changes during use as raw materials are added and processed molten metal, matte and / or slag flows from the furnace.

[0044] Therefore, in the exemplary embodiment, a plurality of non-contact sensors 30.1 and 30.2 are provided to monitor the height at a plurality of discrete locations on the upper surface 24. Each of the non-contact sensors is configured to sense a respective distance between a respective reference point and a respective one of the plurality of discrete locations on the upper surface 24, and the controller is operable to generate profile data associated with the upper surface 24 from the respective sensed distances.

[0045] The non-contact sensor may be any suitable sensor, but preferably comprises a microwave radar sensor, such as those sold under the trade names VEGA or Siemens. The radar sensor comprises a radar transceiver device 36, 38 housed in an original manufacturer ("OM") housing 54. The transceiver device 36, 38 comprises a transmitter 36 and a receiver 38.

[0046] The emitter and collector may be contained in a horn antenna 40. The horn antenna 40 is mounted at a suitable location in the roof area, such as below the roof 18 (not shown), within a channel defined in the roof 18 (not shown), or above the channel, such as Figures 2 to 4 shown.

[0047] The horn antenna 40 may be mounted in a chamber 60 defined by a post 62 mounted in a channel 64 in the top 18. The chamber 60 may be in communication with a supply conduit 66 for a suitable cooling fluid to cool the outer surface of the horn antenna.

[0048] A waveguide 46, which is fixed at one end to the housing 54 and at the other end to the horn antenna, connects the transceiver device to the horn antenna to guide the electromagnetic signal 42 from the transmitter 36 of the transceiver device to the horn antenna and there to be emitted toward the surface 24. The reflection 44 is collected by the horn antenna and guided by the waveguide 46 to the receiver 38 of the transceiver device. Figure 4 As shown, an inlet 68 for a suitable cooling fluid may be defined in the waveguide 46 to cool the horn antenna from the inside.

[0049] like Figure 2 and 3As shown, the transceiver devices 36, 38 may be located outside the container, adjacent to an outer surface of at least one of the side walls 16 or the bottom 14 of the container 12. The transceiver devices 36, 38 may be located at any suitable distance d1 from the container. Figure 2 and Figure 3 As shown, the transceiver devices 36, 38 may be located proximate to a side wall (not shown) or spaced a distance therefrom. Figure 2 In the embodiment, the transceiver devices 36, 38 are located at a height l below the upper surface 24. u of the horizontal plane, and Figure 3 In the embodiment, the transceiver devices 36, 38 are located at a height l above the upper surface 24. u and the lower height l l The horizontal plane between.

[0050] It will be appreciated that the waveguide 46 must be of the required length to connect the transceiver devices 36, 38 located at the above-mentioned locations to the horn antenna 40 at the top region of the vessel.

[0051] Figure 4 Another example embodiment of the electric furnace 10 is shown. In this embodiment, the transceiver device includes a transmitter 36 and a receiver 38 housed in an OM housing 54, and the transceiver device is located at any level relative to the layer 22, including a height l above the upper surface 24. u , and beyond a first line 39, the first line 39 is spaced apart from the layer at a distance d0>0 on a second line 41, the second line 41 being perpendicular to the central axis 19, and the first line 39 extending parallel to the central axis 19. In this particular embodiment, the transceiver devices 36, 38 may be located at a level several meters higher than the top 18.

[0052] Electromagnetic interference (EMI) in the furnace above the layer 22, emanating primarily from the electrode 23 energized at 50 Hz, is sufficiently attenuated by the side walls 16 and distance (according to the inverse square law), and to such an extent that no special EMI protective shielding is required for the radar transceiver devices 36, 38 in the OM housing 54 or any other part of the non-contact sensor 30.

[0053] exist Figure 5, an exemplary embodiment of a supply assembly 70 is shown. The assembly includes a housing 72 defining an inlet 74 for feedstock on a top wall of the housing and an outlet 76 for feedstock on a bottom wall of the housing. The outlet 76 is linearly offset relative to the inlet 74. Thus, a curved passage 78 for feedstock extends between the inlet 74 and the outlet 76. The horn antenna 40 is mounted in or on the housing just above the outlet 76 so that it has a direct line of sight through the outlet and so that there is a straight path through the outlet 76 for the signal 42 and reflection 44 between the antenna 40 and the surface 24.

[0054] A heat shielding system 80 may be provided to protect the antenna 40 from radiant heat from the process in the furnace. The shielding system may include a selectively openable and closable shielding window 82 between the antenna and the outlet 76 (and thus the process), and optionally a side wall 84 between the antenna 40 and the passage 78. The shielding window 82 may be in the form of a "sliding door" or shutter that may be selectively controlled by at least one of a manual, electric, hydraulic, or pneumatic control 86.

Claims

1. An electric melting furnace, comprising: at least one electrode; A container comprising a bottom, at least one side wall and a top region including a top, the container holding a body of material to be processed, the container having a central axis extending between the top and the bottom, the body of material comprising at least one layer having an upper surface, the upper surface having an upper height (l u ) and the lower height (l l ), wherein the at least one electrode extends through the top into the container; and at least one non-contact sensor for sensing the distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transmitter, an electromagnetic signal receiver, an electromagnetic signal transmitter facing the upper surface, the transmitter being located at a certain distance above the upper surface in the top area of ​​the furnace, a collector for reflecting the signal emitted from the upper surface, and a signal conduit located at at least one of the following positions: a) between the transmitter and the transmitter, and b) between the receiver and the collector, wherein at least one of the transmitter and the receiver is located at one of the following positions outside the container: a) below the upper height of the upper surface (l u ) of the horizontal plane; and b) above the height above the upper surface (l u ) and exceeds the first line, the layer spacing distance d0 of the first line on the second line is >0, the second line is perpendicular to the central axis, and the first line extends parallel to the central axis.

2. The furnace of claim 1, wherein the layer is a top layer of raw material.

3. The furnace according to any one of claims 1 and 2, wherein: The at least one contactless sensor is connected to a controller for generating data related to the sensed distance.

4. The furnace of claim 3 , comprising a plurality of said non-contact sensors connected to said controller, each of said non-contact sensors being operable to sense a respective distance between a respective reference point and a respective one of a plurality of discrete locations on said upper surface, said controller being operable to generate profile data associated with said upper surface from the respective sensed distances.

5. The furnace according to any one of claims 1 to 4, wherein the transmitter and the receiver are located at a level lower than the upper height of the upper surface.

6. The furnace according to any one of claims 1 to 4, wherein the transmitter and the receiver are located at a level between the upper level and the lower level of the upper surface.

7. The furnace of any one of claims 5 and 6, wherein the transmitter and the receiver are located adjacent an outer surface of the at least one side wall of the vessel.

8. The furnace according to any one of claims 5 and 6, wherein the transmitter and the receiver are spaced apart from the container.

9. The furnace according to any one of claims 1 to 4, wherein the transmitter and the receiver are located at a level higher than the upper height of the upper surface.

10. The furnace according to any one of claims 1 to 9, wherein: The at least one non-contact sensor includes any one of a laser sensor, an automatic detection sensor, an acoustic sensor, an optical sensor, a muon particle sensor, a pulse or frequency modulated electromagnetic sensor, an ultrasonic sensor, and a yo-yo sensor.

11. The furnace according to any one of claims 1 to 9, wherein: The at least one contactless sensor comprises a radar sensor.

12. The furnace according to claim 11, wherein: The radar sensor includes a microwave radar transceiver device serving as the transmitter and the collector, an antenna, and a waveguide connecting the transceiver device to the antenna.

13. The furnace of claim 12, wherein the antenna is a horn antenna.

14. A furnace according to any one of claims 1 to 13, comprising a material supply arrangement located at a raw material port in the top, the material supply arrangement comprising a box, the box defining a raw material inlet located in a top wall of the box and a raw material outlet located in a bottom wall of the box, the inlet being linearly offset relative to the outlet, and wherein the emitter and collector are positioned in line with the outlet to have a line of sight through the outlet.

15. An electric melting furnace comprising: at least one electrode; a container comprising a bottom, at least one side wall, and a top region including a top, the container holding a body of material to be processed, the container having a central axis extending between the top and the bottom, the body of material comprising at least one layer having an upper surface, the at least one electrode extending through the top into the container; and At least one non-contact sensor for sensing the distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transceiver device, an antenna located at a certain distance above the upper surface in the top area of ​​the furnace, and a signal conduit extending between the electromagnetic signal transceiver device and the antenna, wherein the transceiver device is located at a predetermined position outside the container, at which predetermined position, at least one of the container and the distance attenuates electromagnetic interference EMI inside the container to such an extent that an EMI protective cover of the transceiver device is omitted except for the original manufacturer's housing of the transceiver device.

16. A method of operating an electric furnace, the electric furnace comprising a vessel including a bottom, at least one side wall and a top region including a top, the vessel containing a body of material to be processed, the body of material including at least one layer having an upper surface; at least one electrode extending through the top into the vessel; and at least one non-contact sensor for sensing a distance between a reference point and a position on the upper surface, the non-contact sensor comprising an electromagnetic signal transceiver device, an antenna spaced above the upper surface in the top region of the furnace, and a signal conduit extending between the electromagnetic signal transceiver device and the antenna, the method comprising: positioning the transceiver device outside the container; The signal conduit and at least one of the container and the distance to the transceiver device are used to attenuate electromagnetic interference EMI present inside the container to such an extent that at the transceiver device, no EMI protective cover is provided for the transceiver device except for the original manufacturer's housing for the transceiver device.

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