NL2003916C2

NL2003916C2 - Hot blast transportation apparatus, comprising a refractory lining contained within a steel outer shell.

Info

Publication number: NL2003916C2
Application number: NL2003916A
Authority: NL
Inventors: Jan Soonius; Jacobus Laar
Original assignee: Heatteq Refractory Holding B V
Priority date: 2009-12-07
Filing date: 2009-12-07
Publication date: 2011-06-09

Description

Hot blast transportation apparatus, comprising a refractory lining contained within a steel outer shell

The invention relates to a hot blast transportation apparatus, comprising a refractory lining contained within a steel outer shell, wherein said refectory lining delimits a transportation channel for the hot blast, which refractory lining has at 5 least one first expansion joint, and wherein the steel outer shell has a second expansion joint, in the vicinity of which said steel outer shell is provided with a bellow or bellows to accommodate for expansion and retraction of the refractory lining and the outer shell respectively due to temperature- and/or 10 pressure-variations, and wherein the at least one first expansion joint of the refractory lining is provided with means to prevent heat radiation caused by a continuous stream of hot gas reaching the bellow or bellows.

Such a hot blast transportation apparatus may for in-15 stance be a hot blast main providing a transportation channel for hot blast from a hot blast stove or stoves to a blast furnace .

Such a hot blast transportation apparatus may also be the external channel connecting the burner shaft to the dome of 20 a hot blast stove with external burner shaft, or a hot blast outlet, or the tuyere-stock.

All the mentioned apparatuses are common to the person skilled in the art of the iron and steel industry and comprise a refractory lining contained within a steel outer shell, wherein 25 said refectory lining has at least one first expansion joint, and wherein the steel outer shell has at least one second expansion joint, in the vicinity of which said steel outer shell is provided with a bellow or bellows to accommodate for expansion and retraction of the refractory lining and the outer shell, re-30 spectively.

Taking as an example a hot blast main, the refectory lining of this hot blast transportation apparatus has during operation a temperature profile that vairies from 1350°C on the inside facing the transportation channel, to 150°C immediately 35 adjacent to the steel outer shell. The steel outer shell then has a temperature of approximately 120°C.

During heat up from ambient to operating temperature both the refractory lining and the steel outer shell are subject 2 to thermal expansion and to accommodate for this the refractory lining as one or more first expansion joints, and the steel outer shell has one or more second expansion joints.

Normally the refractory lining comprises several layers 5 of refractory material, each layer having its own expansion joints, and all expansion joints being filled with ceramic felt that can be compressed. When after an operational period the blast furnace is taken out of production, for instance for a revamp or maintenance of lesser importance, the hot blast main in-10 eluding its refractory lining and steel outer shell is cooled down. As a consequence thereof the refractory lining and steel outer shell retract and the ceramic felt within the expansion joints expands in order to prevent heat radiation caused by a continuous stream of hot gas reaching the bellow or bellows 15 through the expansion joints.

The problem with this prior art construction is however that the ceramic felt has poor elasticity so that after a few heat up and cool down cycles, the ceramic felt will not return to its original thickness and the operational effect of the felt 20 within the expansion joints will deteriorate. This results in that hot gases will eventually come to flow continuously from within the transportation channel towards the steel outer shell, in particular the steel bellows causing hot spots and ultimately also damage to the steel bellows.

25 It. is an object of the invention to remove or at least alleviate the occurrence of this problem.

To this end a hot blast transportation channel is proposed in accordance with one or more of the appended claims.

Essentially the hot blast transportation channel of the 30 invention has the feature that said means to prevent heat radiation are embodied as a compressible and resilient hose that is provided within said at least one first expansion joint so as to be able to adapt to the dimensions thereof. With this in retrospect astonishingly simple measure it is possible to remove the 35 prior art problem which has given persons skilled in the art a headache for decades.

Beneficially the hose is provided circumferentially in the at least one first expansion joint so as to substantially surround the transportation channel for the hot blast.

40 Desirably the hose is provided with apertures to miti gate pressure variations in the hose.

3

It is further preferred that the hose is provided in the at least one first expansion joint in an area adjacent to the steel outer shell. The temperatures near the steel outer shell are relatively low, which is beneficial for the longevity 5 of the hose.

The inventors have found that to provide a sufficiently compressible and flexible hose that is also provided with sufficient endurance, it is desirable that the hose is a corrugated stanless steel hose.

10 The invention will hereinafter be further elucidated with reference to a non-limiting example as provided in the attached drawing.

In the drawing: -figure 1 shows a part of a hot blast transportation 15 apparatus according to the prior art; -figure 2 shows the hot blast transportation apparatus of figure 1, wherein the ceramic felt has lost its original elasticity; -figures 3 and 5 show a part of a hot blast transporta-20 tion apparatus according to a first and a second embodiment of the invention in a relatively cool state; and -figures 4 and 6 show the hot blast, transportation apparatus of figure 3 respectively figure 5, after heat up, with the expansion joints essentially closed.

25 Wherever in the figures the same reference numerals are applied, these numerals refer to the same parts.

With reference first to figure 1 and figure 2, a part 1 of a hot blast transportation apparatus is shown that provides a transportation channel 2. As an example may serve the hot blast 30 main for transporting hot blast from a hot blast stove or stoves (not shown but known to those skilled in the art) to a blast furnace (also not shown yet also known to those skilled in the art), comprising a refractory lining 3 contained within a steel outer shell 4, wherein said refectory lining 3 has at least one 35 first expansion joint 5, and wherein the steel outer shell 4 has a second expansion joint 6, in the vicinity of which second expansion joint 6 said steel outer shell 4 is provided with a bellow 7 or bellows to accommodate for expansion and retraction of the refractory lining 3 and the outer shell 4 respectively, due 40 to pressure- and/or temperature-variations.

Figure 1 and figure 2 show one first expansion joint 5 4 of the refractory lining 3 which is provided with ceramic felt 8 to prevent heat radiation caused by a continuous stream of hot gas reaching the bellow 7 or bellows from within the transportation channel 2 for hot blast. As opposed to figure 1, in figure 5 2 the ceramic felt 8 has lost its original elasticity due to re peated heat up and cool down cycles of the hot blast main 1.

This may eventually lead during operation to a continuous stream of hot gas symbolized by the arrow 10 to the below 7 or bellows that are applied to bridge the second expansion joints 6 of the 10 steel outer shell 4, giving rise to hot spots and damage to said bellow 7 or bellows.

Turning now to the invention as embodied in the hot blast, transportation apparatus 1 shown in figure 3 resp. figure 5 and figure 4 rep. figure 6, these figures illustrate that the 15 means to prevent heat radiation caused by a continuous stream of hot gas reaching the bellow 7 or bellows, are according to the invention embodied as a compressible and resilient hose 9 that is provided within said at least one first expansion joint 5 of the refractory lining 3.

20 The difference between the embodiment shown in figures 3 and 4 and the embodiment shown in figures 5 and 6 is that the area in which concrete 11 is applied as part of the ceramic lining 3 is larger in the embodiment shown in figures 5 and 6.

Although not shown in figures 3 (resp. 5) and 4 (resp. 25 6) it will be clear to the artisan how to implement the pre ferred arrangement to provide the hose 9 circumferentially in the at least one first expansion joint 5 of the refractory lining 3 so as to substantially surround the transportation channel 2 for the hot blast. It can further be mentioned that it is pre-30 ferred that the hose is provided with apertures to mitigate pressure variations in the hose 9.

Figures 3 and 4 and figures 5 and 6, respectively do show the preferred construction that the hose 9 is provided in the at least one first expansion joint 5 of the refractory lin-35 ing 3 in an area adjacent to the steel outer shell 4.

As is shown in figure 4 and figure 6 the stream of hot gas symbolized by the arrow 10, which in the prior art may eventually reach the bellow 7 or bellows, is in these embodiments of the invention interrupted by the operation of the hose 9.

40 Finally the inventors remark that effectively the hose 9 is a corrugated stainless steel hose. This is not shown in 5 figures, but the person skilled in the art is entirely familiar with the construction of such a corrugated stainless steel hose. A showing in the drawing and discussion thereof can therefore be dispensed with.

Claims

A hot wind transport device (1), comprising a refractory line (3) mounted in a steel outer wall (4), wherein the refractory line (3) defines a hot wind transport channel (2), which refractory line (3) at least 5 has a first expansion joint (5), and in which the steel outer wall (4) has a second expansion joint (6), in the vicinity of which steel outer wall (4) a bellows (7) or bellows are provided to prevent expansion and contraction of to receive the refractory line (3) or the steel outer wall (4) as a result of temperature and / or pressure variations, and in which the at least one first expansion joint (5) of the refractory line (3) is provided with means to prevent heat radiation due to a continuous stream of hot wind reaching the bellows (7) or bellows, characterized in that said means for preventing heat radiation are designed as a compressible and resilient hose (9) which is provide said at least one first expansion joint (5) in order to be able to adapt to the dimensions thereof.

Hot wind transport device (1) according to claim 20, characterized in that the hose (9) is provided in the circumferential direction in the at least one first expansion joint (5) in order to substantially completely transport the hot wind transport channel (2) to be surrounded.

Hot wind transport device (1) according to claim 25. or 2, characterized in that the hose (9) is provided with openings to prevent pressure variations in the hose.

4. Hot wind transport device (1) according to any of claims 1-3, characterized in that the hose (9) is provided in the at least one first expansion joint (5) in an area near the steel outer wall (4).

A hot wind transport device (1) according to any one of claims 1-4, characterized in that the hose (9) is a corrugated stainless steel hose.