Patent Application
20240318916
The subject of the disclosure is a shielding shoe for covering openings in the bottom of a walking beam furnace. The shielding shoe is attached to a vertical support of the walking beam furnace in the area of a semi-circular recess and essentially consists of refractory cast concrete or refractory rammed concrete.
A walking beam furnace, with shielding shoe according is also disclosed herein.
The shielding shoe is a refractory prefabricated part which is installed to cover the scale funnels and slot openings in the bottom of walking beam furnaces. Walking beam furnaces are used in rolling mill plants to heat slabs, ingots or billets to rolling temperature. The walking beam conveyors consist of walking beams which are supported by vertical supports, the so-called supports, also called support tubes or lifting support tubes, and to which the working movement is given in the form of a rectangular orbit over the supports. The latter consist of high-strength steel pipes with ceramic jackets and associated pipe cooling. The supports pass through approximate slot-shaped openings at the bottom of the oven, whereby the drive of the walking beam conveyor together with additional units can be arranged below the bottom of the oven or the oven floor. Two shielding shoes per support are fixed above the slots and are thus intended to avoid or reduce the loss of energy from the oven due to direct radiation into the water cup. The shielding shoes are subject to heavy wear and must therefore be replaced at certain intervals.
The state-of-the-art shielding shoes are made of fireproof concrete with a fixing plate welded to the support. Slotted pins of various lengths are arranged on the sheet to fix the refractory concrete to the sheet. Two shielding shoes are each placed on a separate plate-like steel bracket to accommodate the increased weight of the prefabricated components.
Conventional shielding shoes have the following disadvantages:
From DE 20 2019 002 656 U1, a shielding shoe is already known which has a steel-free shielding body and is thus already fired or sintered before assembly. However, the shielding shoe according to DE 20 2019 002 656 U1 is equally a heavy, unwieldy component that is difficult to assemble in confined spaces such as those found in walking beam furnaces.
The inventive embodiments disclosed herein provide a shielding shoe that can be mounted more easily.
The disclosed shielding shoe has a honeycomb-like structure underneath the shielding jacket. The honeycomb-like structure is also made of refractory cast concrete or refractory rammed concrete. Thus, the shielding shoe essentially consists only of cast and fired (up to 1,400° C. possible) refractory cast concrete or refractory rammed concrete.
The honeycomb structure makes the shielding shoe considerably lighter than conventional shielding shoes. A weight saving of more than 35% is possible. The honeycomb-like structure nevertheless ensures the required stability.
Preferably, the shielding jacket above the honeycomb-like structure has a constant thickness. This minimises stresses in the material.
It is favourable if the honeycomb structure, i.e. the webs of the honeycombs, have a uniform wall thickness; this also reduces stresses.
In a preferred embodiment, the shielding shoe has curved slots in the area of the recess for the support, which are C-shaped in top view, for example, so that it can be hooked onto holding clamps attached to the support. The curved clamps ensure a secure hold. In addition, the shielding shoe can rest on a supporting ring attached to the support. It is advantageous if a holding clamp and a supporting ring half each form a one-piece component, which makes assembly on the support particularly easy. However, they can also be separate components.
Preferably, the shielding shoe has at least one, preferably two, clamp holes on its upper side, i.e. in the shielding jacket. Clamps can then be turned into these clamp holes as an assembly aid.
Normally, two shielding shoes are mounted per support. To prevent falling scale from coming to rest on the two shielding shoes, the shielding jacket slopes downwards towards the edges so that falling scale slides off it. Consequently, the two shielding shoes form an umbrella shape.
Also disclosed is a walking beam furnace having at least one support projecting through an opening in the bottom of the walking beam furnace. As disclosed herein, two of the shielding shoes are attached to the support.
In the following, the state of the art and an embodiment of the invention is described on the basis of drawings. In these drawings:
The ceramic fibre mat 5 is attached to the rolled sheet 3 with the anchors already welded on as slotted pins 4. Then the slotted pins 4 are spread apart. The entire unit forms a shielding shoe 2 with the refractory cast concrete cast in a mould.
A halved cast plate 6 (also called a plate) is used for mounting and supporting the shielding shoe 2. The two parts (left and right) of the cast plate 6 are placed on the support 1 in a predetermined position, welded on and covered with a ceramic fibre mat 7.
Two shielding shoes 2 are needed to completely cover the slot in the floor. During assembly, one shielding shoe 2 is placed on one half of the cast plate 6 and the other on the second half. Both shielding shoes 2 are welded to the support 1 with the rolled sheet 3.
To change a shielding shoe 2, the welded-on sheets 3 must be detached from the support 1 and the sheets 3 of the new shielding shoes 2 must be welded on again at the same position.
To mount or dismount the new shielding shoe 1a, it is pushed onto or removed from the new holding clamps 2a. For this purpose, two curved slots 10a are provided in the shielding shoe 1a in the area of its semi-circular recess 9a, in which the two legs of the holding clamp 2a can be received. Due to the curved shape of the slots 10a, the shielding shoe 1a is held securely and the risk of stress cracks is minimised. Furthermore, the shielding shoe 1a rests on a circular supporting ring 6a.
The upper side of the shielding shoe 1a is formed by the shielding jacket 8a. The shielding jacket here has a uniform thickness X. Below the shielding jacket is the honeycomb-like structure 7a, which is also made of refractory cast concrete or refractory rammed concrete. This honeycomb structure is produced by pouring the concrete into a corresponding casting mould in which the future webs of the honeycombs are recessed. In this example, the honeycomb structure 7a has a uniform wall thickness Y.
To facilitate assembly/disassembly, a block hole 3a is provided in the shielding shoe 1a. During assembly/disassembly, a block with an eyelet is screwed into the block hole 3a, into which the hook of a lifting tool can then be hooked. For operation, the block hole 3a can be sealed with a refractory compound.
The new shielding shoe 1a is thermally pre-treated (up to 1,400° C. is possible). This enables permanent storage in a dry and frost-free place without any loss of quality.
In this example, two identical shielding shoes 1a are attached to the support 5a. What they have in common here is an elliptical floor plan (see
The described embodiment has the following advantages:
| Number | Date | Country | Kind |
|---|---|---|---|
| A50030/2021 | Jan 2021 | AT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/081050 | 11/9/2021 | WO |
