Patent Grant
12135168
The present invention relates generally to tap holes of a metal furnace, and more particularly, to an apparatus and method for densification of a region around the tap hole.
Eccentric bottom tap electric arc furnaces (EBT EAF) are equipped with an exit mechanism, which allows for safe discharge of liquid steel from the furnace at the end of the melting cycle. This mechanism is referenced by those skilled in the art as “tap hole”. A typical EBT EAF 10 and tap hole 12 are shown in
The bottom of the EAF 10 is normally constructed using a dry basic monolithic material composed from magnesia, dolomitic magnesia, dolomitic materials, or a combination of these materials. Because these materials are unshaped and in bulk consistency, they are densified during installation of the bottom portion of the EAF 10 with special densification tools. These tools use compression or vibration during the densification process, and are well suited for the densification of the EAF bottoms.
When repairing the EAF 10, entry into to EAF by the installation operators is only possible after the EAF 10 is cooled down. This is not the optimum scenario from the EAF equipment utilization rate perspective, as such cool down requires time, sometimes more than 8 hours and up to 24 hours. During the cool down period the EAF cannot be used for the melting and production of steel.
Some densification tools have been adjusted for use in a hot furnace. In that case the tools are placed into the EAF 10 by a crane and do not require entry by the operator. This procedure requires that the roof of the EAF 10 be moved into an open position so the crane has an open path to place the tool in the EAF and perform the densification process. This hot repair method improves the EAF utilization rate.
Conventional densification of the dry monolithic material in the tap hole region is done with the use of lance pipe (e.g., an elongated rod or pipe that is inserted into the monolithic material). This tool is hand operated by the repair/installation personnel. The repair is typically done thru a sump panel sanding hole and exposes the operator to a hot and unsafe environment. Further, the process is very inefficient and time-consuming and extremely dependent on the skill and performance of the installation operator. Due to the differences in skill and the difficult work environment, using a lance pipe to aerate and pack the material in the tap hole region may not achieve the required densification. Poor densification of the dry material in the tap hole 12 and surrounding region results also in low support of the tap hole components and leads to sub-standard performance of the tap hole assembly, which in turn leads to more frequent maintenance of the tap hole 12. This not only increases the EAF operation cost associated with the use of more tap hole components, but also causes more frequent repairs, thereby decreasing the utilization rate of the equipment.
Aspects of the invention are directed to a tool for densification of dry refractory material in and around the tap hole by aerating the material through vibration as the material is being installed. The shape of the tool allows it to come in through a sump panel tap-hole sanding hole and fit between the tap hole and surround block to vibrate the material as it is being installed.
A tool according to aspects of the invention has a plate-like structure that is shaped to fit within a gap between internal and external components of the tap hole, e.g., the plate-like structure has an arc shape that corresponds to a gap defined by the tap hole and the surround block. The plate-like structure includes a plurality of elongated members, e.g., rods, fixed thereto, the rods having a predetermined length and extending outward in a direction perpendicular to a major surface of the plate-like structure. The rods may be fixed to the plate via bolts, threads and/or welds. On a side opposite from that in which the rods extend, the plate-like structure includes a mounting means for attachment to a vibration machine. The mounting means may be a sleeve with and/or compression device or other fixing means to fix the plate-like structure to an actuator coupled to the vibration machine.
An advantage of the device and method in accordance with the invention is that it can be used to increase the density of the dry material around the tap hole during installation, thereby increasing performance of the tap hole. Additionally, operating cost and down-time of the EAF equipment due to replacement of internal sleeves is decreased.
According to one aspect of the invention, a method is provided for densification of refractory material in a gap between a tap hole sleeve of a furnace and a surround block of the furnace, the surround block surrounding the tap hole sleeve. The method includes: positioning a tool in the gap, the tool including a support having opposing surfaces and a sidewall connecting the opposing surfaces, the opposing surfaces having an arcuate shape, a plurality of elongated members extending from one of the opposing surfaces, and a connector arranged on the other of the opposing surfaces; filing the gap with dry material; and applying vibration to the tool to densify the dry material.
In one embodiment, filling the gap with dry material includes using at least one of magnesia, dolomitic magnesia or dolomitic material as the dry material.
In one embodiment, applying vibration includes attaching a vibration machine to the connector, wherein the vibration machine applies a vibrating motion to the tool.
In one embodiment, positioning the tool includes maneuvering the tool through a sump panel sanding hole of the furnace.
In one embodiment, applying vibration includes using at least one of a mechanically-powered vibration device, a pneumatically-powered vibration device or an electrically-powered vibration device to apply the vibration to the tool.
In one embodiment, filing the gap with dry material includes filing the gap in layers having a prescribed thickness.
In one embodiment, the prescribed thickness is less than a length of elongated members.
In one embodiment, the steps of filing the gap and applying vibration are performed simultaneously.
In one embodiment, the steps of filing the gap and applying vibration are performed sequentially.
According to another aspect of the invention, a tool for densification of refractory material in a tap-hole of a furnace, the tool comprising: a support having opposing surfaces and a sidewall connecting the opposing surfaces, the opposing surfaces having an arcuate shape;
a plurality of elongated members extending from one of the opposing surfaces; and
a connector arranged on the other of the opposing surfaces, the connector comprising a fastener configured to selectively and fixedly couple the connector to a vibrating member.
In one embodiment, at least some of the plurality of elongated members include a channel formed within the respective elongated member, the channel opening at an end of the respective elongated member distal from the support.
In one embodiment, at least some of the plurality of elongated members comprise a pipe.
In one embodiment, the arcuate shape is dimensioned to correspond to the tap hole of the furnace.
In one embodiment, the plurality of elongated members extend in a direction perpendicular to a major face of the opposing surfaces.
In one embodiment, the support comprises a metal plate.
In one embodiment, an end of at least some of the plurality of elongated members that is distal from the support is tapered.
In one embodiment, at least some of the plurality of elongated members are welded to the support.
In one embodiment, at least some of the plurality of elongated members are threadedly attached to the support.
In one embodiment, an end of at least some of the plurality of elongated members extends through the support, a first fastener is threadedly coupled to the respective elongated member and arranged on one of the opposing surfaces, and a second fastener is threadedly coupled to the respective elongated member and arranged on the other of the opposing surfaces.
In one embodiment, an outer radius of the opposing surfaces is between 14-16 inches, and an inner radius of the opposing surfaces is between 10-12 inches.
In one embodiment, the connector comprises a sleeve configured to receive to a vibrating member.
In one embodiment, the fastener comprises one of a clamp or a bolt.
In one embodiment, the tool includes a vibration device coupled to the connector.
In one embodiment, the opposing surfaces are planar surfaces that are substantially parallel to each other.
In one embodiment, the support has a length defined along a major axis of the support, and a width defined along a minor axis of the support, and a height defined between the opposing surfaces, the length being greater than the width, and the width being greater than the height.
In one embodiment, the fastener comprises a through hole formed in a portion of the connector.
In one embodiment, the fastener further comprises one of a threaded bolt configured for insertion into the through hole and a nut threadedly engagable with the bolt, or a pin configured for insertion into the through hole and a clip attachable to the pin.
According to another aspect of the invention, a system for densification of refractory material in a tap hole includes the tool as described herein, and a vibration device coupled to the tool.
Examples of the specific embodiments are illustrated in the accompanying drawings. While the invention will be described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to such specific embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in details so as to not unnecessarily obscure the present invention.
These and other advantages will become apparent from the following description of a preferred embodiment taken together with the accompanying drawings and the appended claims.
The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:
Various aspects now will be described more fully hereinafter. Such aspects may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art.
The word “about” when immediately preceding a numerical value means a range of plus or minus 10% of that value, e.g., “about 50” means 45 to 55, “about 25,000” means 22,500 to 27,500, etc., unless the context of the disclosure indicates otherwise, or is inconsistent with such an interpretation. For example, in a list of numerical values such as “about 49, about 50, about 55, “about 50” means a range extending to less than half the interval(s) between the preceding and subsequent values, e.g., more than 49.5 to less than 52.5. Furthermore, the phrases “less than about” a value or “greater than about” a value should be understood in view of the definition of the term “about” provided herein.
As used herein, the term “refractory material” refers to inorganic nonmetal materials utilized in various high-temperature equipment, e.g., steel production and the like. Refractory materials are characterized by a high melting point, and when exposed to high temperatures they do not lose their strength and of form.
An exemplary tap hole area 12 is shown in
Formed between the internally-arranged tap hole sleeve 14 and the external surround block 16 is a gap 26 designed to be between about 2½ to 4 inches wide. The gap 26 is filled with the same, or similar, dry monolithic material used for the construction of the EAF bottom. Because the gap 26 is very narrow, existing tools for EAF repair are not used for the new installation of tap hole sleeve 14 or hot repair of the tap hole replacement sleeve 14.
A tool in accordance with the invention can be used to achieve a required density of dry refractory material in the gap 26 of the tap hole 12. In this regard, the required density is achieved by aerating the material through vibration of the tool as the dry material is installed into the gap 26 of the tap hole 12. The shape of the tool allows it to come in through the sump panel sanding hole and fit between the surround block 16 and the tap hole sleeve 14 to vibrate the dry material in the gap 26 as the dry material is being installed. The densification tool is positioned within the gap 26 between the internal tap hole sleeve 14 (also referred to simply as the “tap hole”) and the external surround block 16 (also referred to simply as the “surround block”), and the dry material (e.g., Americlase) is poured in to fill the gap 26 between the internally-arranged tap hole sleeve 14 and the surround block 16. A vibrating device attached to the tool aerates the dry material, thereby increasing the packing (density) of the dry material.
As will be discussed in further detail below, a head of the tool is complemented with a series of elongated members, e.g., pipes, dimensioned to allow easy placement within the gap 26. The tool includes a connection member for connection to the vibrating source, thereby enabling densification of the dry material by vibration force.
Referring to
The tool 30 further includes a plurality of elongated members 34 extending from surface 32a, and a connector 36 extending from the surface 32b. As can be seen in
In the embodiment illustrated in
In use, the gap 26 is filled with the material to be densified, the connector 36 of the tool 30 is attached to the vibration device, and the tool is placed in the material within the gap 26. The vibration device, which may be a mechanically-powered vibration device, a pneumatically-powered vibration device, an electrically powered vibration device, or the like, is activated and the tool is held in place for a predetermined amount of time to densify the material.
Filling the gap and applying vibration may be done sequentially. For example, a layer of material may be deposited in the gap, the layer having a prescribed thickness. Preferably, the thickness of each layer is less than a length of the elongated members. Upon achieving a desired layer thickness, the tool may be inserted into the material and vibration applied to the tool to densify the layer of material. Once the material has been densified, the process may be repeated where another layer is deposited over the already densified layer, and vibration is again applied. This can be repeated until a desired thickness of densified material has been obtained.
As an alternative to the sequential approach described above, filling the gap with material and applying vibration may be done simultaneously. For example, vibration can be applied to the tool after the initial layer is deposited in the gap, thereby densifying the initial layer. While vibration is being applied to the tool, additional material may be deposited in the gap to build the thickness of the layer of material. The simultaneous application of material and vibration is advantageous in that it can speed up the densification process.
Moving to
In the illustrated embodiments of
Moving to
Moving to
It should be noted that the features of the elongated member shown in
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purposes of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.
This application claims the benefit of U.S. Provisional Application No. 63/223,328 filed Jul. 19, 2021, which is hereby fully incorporated herein by reference.
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| 107858480 | Mar 2018 | CN |
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| Sutherland, J. J. et al. (2019). Managing the tap-hole life-cycle at five submerged arc furnaces producing silicomanganese at Transalloys. Journal of the Southern African Institute of Mining and Metallurgy, 119(6), 563-571. |
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| Number | Date | Country | |
|---|---|---|---|
| 20230024399 A1 | Jan 2023 | US |
| Number | Date | Country | |
|---|---|---|---|
| 63223328 | Jul 2021 | US |
