EP0536521B1 - Walking beam furnace - Google Patents

Description

The invention relates to a walking beam furnace, according to the preamble of claim 1.

Walking beam furnaces and pacemaker furnaces have long been known for conveying annealing material, in particular slabs during annealing. They are preferred for use in rolling mills because they heat up more evenly and transport the annealing material without causing damage, e.g. Ensure pusher furnaces.

When transported through the furnace, the annealing material is deposited on the fixed beam for a few minutes after each stroke. On the one hand, these transport breaks enable the annealing material to remain in the furnace for a sufficient time, and on the other hand, the lifting beams can return to their lowered starting position. Since also at high furnace temperature, the shape and the load-bearing capacity of the lifting and fixed beams must be maintained, they usually consist of pipes through which coolants flow. When the annealing material rests on the cooled fixed beam, however, temperature differences of up to 150 ° C, so-called cooling shadows, occur at the contact points of the annealing material.

Differences in temperature of the annealing material affect the Surface quality, the dimensional accuracy and the technological properties of the annealing material, so that the rolling mill strives to reduce the inevitable temperature differences in the annealing material to below 30 ° C.

German Offenlegungsschrift 34 40 126 describes a continuous furnace in which the beam sections essentially having a common longitudinal axis alternately consist of fixed beam sections and walking beam sections, and the fixed beam sections following the first fixed beam section are angled laterally at their ends facing the beginning of the furnace and are guided past the adjacent walking beam sections are.

With this walking beam furnace, support points of the annealing material that change in the feed direction can be created on the lifting and fixed beams, whereby the same dimensions as a walking beam furnace with fixed beams and walking beams that are continuous in the feed direction can be maintained without having to accept the limitations of the annealing material dimensions to be charged.

This known walking beam has proven itself, but still results in cooling shadows which should be reduced as much as possible in the case of particularly high demands on the quality of the finished product produced from the annealing material.

A similarly designed walking beam furnace is described in French Offenlegungsschrift 2,569,262. The fixed beams and the walking beams are arranged at equal distances from one another, the fixed beams and the walking beams in the middle of the furnace having essentially the same transverse displacement, which corresponds to a quarter of the space between two fixed beams or two walking beams. The fixed beams are supported with supports on the furnace floor, while supports for the walking beams extend through openings in the furnace floor and are arranged on a common travel frame. The annealing material rests on pins arranged on the top of the walking beams and the fixed beams.

In contrast, the PCT published patent application WO 86/01884 describes a support system for supporting heat that is conveyed through a heating furnace, which consists of a supporting tube running in the conveying direction and fitted with this, optionally arranged at a distance one behind the other in the conveying direction, on the top of which there are support surfaces for the heat material. To largely eliminate the cooling effect of the cooled support tube on the surface of the heat material, the riders are placed on the support tube, the support surfaces of which support the heat material are arranged alternately to the left and right of a central plane of the support system. The contact surfaces of the riders arranged one behind the other on the support tube are of such a width and arrangement that they mutually release at least fifty percent of the surfaces of the material in contact with them for heating. For the rider there are mounts on the support tube, of which it is not clear how they interact with the riders. The lower surfaces of the riders rest directly on the support tube, which is why there are recesses in the contact surfaces to reduce the heat transfer between the support tube and the rider.

In the generic German utility model 89 01 064 an attachment piece for coolant-carrying tubes in heating ovens is described, which are provided with at least one locking element directly or indirectly connected to the support tube and with a recess for receiving the locking element, in which the recess or with the recess the receiving part of the locking element connected further recess of the attachment piece is shaped such that a part of the locking element received in the attachment piece is accessible from outside the attachment piece in such a way that the locking element is weldable at the access point with the support tube or a web-shaped intermediate piece to the support tube .

The invention has for its object to provide an improved walking beam furnace, in which there are changing support points of the annealing material on the individual lifting and fixed beams in the feed direction, without it being necessary to change the dimensions of the fixed beams and the walking beams and their distances, in order not to have to accept the limitations of the annealing material dimensions to be charged. Furthermore, the lifting and fixed beams should be designed so that they can easily absorb the high weight of the annealing material, whereby support bars that can be placed on the lifting and fixed beams can be replaced without having to use any tools, but should be secured against falling.

Based on this task, it is proposed that a walking beam furnace of the type mentioned initially has a central support foot on each support web and a support foot at an end area with the support web at a slightly inclined position, extensions that can be pushed under the locking projections, with the longitudinal web in the area of a central support foot and / or a support foot on an end region, lateral projections in the region of the support foot or projections, which prevent longitudinal displacement after the lowering of the supporting web, and that the supporting webs placed on the longitudinal webs run at an angle to the longitudinal axis of the tubes.

These supporting webs are so narrow that they only run obliquely over the width of the lifting or fixed beams, but this results in a sufficient displacement of the support points, which leads to a more uniform temperature distribution in the annealing material.

The longitudinal webs thus serve to hold the supporting webs, which are secured by the projections under the locking projections. While the locking projections are intended to prevent the supporting webs from falling or tipping over from the longitudinal webs, the further projections serve to prevent longitudinal displacement.

The supporting webs can therefore be placed in a simple manner on the lifting or fixed beams by first placing and displacing a somewhat inclined supporting web with a support foot at one end region such that this support foot engages under the corresponding locking projections, after which the inclined supporting web is lowered is so that the central support foot and / or a support foot at the other end region in the longitudinal direction is enclosed on both sides by the projections preventing the longitudinal displacement.

A plurality of successive supporting webs can preferably be fastened on a walking beam and / or fixed beam, so that there is a relatively large angle for the supporting webs and thus the support points change to a sufficiently large extent with each step.

Successive supporting webs can take the same angle to the longitudinal axis and adjacent ends of the supporting webs can be offset with respect to one another in the longitudinal axis.

Likewise, successive supporting webs can assume the same or different, oppositely directed angles to the longitudinal axis and adjoin adjacent ends of the supporting webs.

Preferably, both the walking beam and the fixed beam can be divided into sections in the feed direction and the walking beam and the longitudinal axis Alternate fixed beam sections. This arrangement allows the support points to be moved in addition to the walking achieved by the sloping supporting webs, whereby by alternating the walking beam and fixed beam sections, relatively large distances between the cooling shadows can be achieved, which in addition are the smaller values that result from the result in inclined supporting webs, to move back and forth.

Just as on the continuous walking beam and fixed beam, several successive supporting webs can also be arranged on the walking beam and / or fixed beam sections.

Since the supporting webs must have a considerable mechanical strength due to the high weight of the annealing material, it is advantageous that each supporting web consists of a straight part which connects the supporting feet and rests on the corresponding longitudinal web and a part which projects vertically from it, in each case obliquely from one supporting foot side at one end to the other support foot side at the other end extending support part. In this way, the supporting web is given considerable structural strength, which can carry high loads with little material.

This structural strength is further enhanced by the fact that each support part consists of end regions parallel to the longitudinal web in the region of the end support feet and an oblique intermediate region connecting these end regions.

Another measure for reducing the temperature differences in the area of the cooling shadows contributes to the fact that the lifting and fixed beams or sections have a highly heat-resistant insulation that only leaves the upper area of the supporting webs free.

Fig. 1

eine Draufsicht eines erfindungsgemäßen Hubbalkenofens,

Fig. 2

eine Draufsicht auf einen erfindungsgemäßen Tragsteg,

Fig. 3

eine Seitenansicht eines erfindungsgemäßen Tragstegs und eines diesen tragenden Rohres,

Fig. 4

einen Querschnitt entlang der Linie IV - IV in Fig. 3,

Fig. 5

einen Querschnitt entlang der Linie V - V in Fig. 3 und

Fig. 6

einen Querschnitt entlang der Linie VI - VI in Fig. 3.

The invention is explained below with reference to an embodiment shown in the drawing. The drawing shows:

Fig. 1

a plan view of a walking beam furnace according to the invention,

Fig. 2

a plan view of a supporting web according to the invention,

Fig. 3

2 shows a side view of a supporting web according to the invention and a tube carrying it,

Fig. 4

3 shows a cross section along the line IV-IV in FIG. 3,

Fig. 5

a cross section along the line V - V in Fig. 3 and

Fig. 6

3 shows a cross section along the line VI-VI in FIG. 3.

A walking beam furnace 1 essentially consists of a fire-proof housing 2 with ceiling and side burners 3.

Continuous fixed beams 4 and continuous lifting beams 5 are shown in the upper half of FIG. 1. Both are supported by uprights (not shown) on the oven floor. With regard to these details and the drive of the walking beam 4, reference is made to German Offenlegungsschrift 34 40 126.

Fixed and walking beams are shown in the lower half of FIG. 1, which are divided into fixed beam sections 6 to 9 and walking beam sections 10 to 13. These sections 6 to 9 and 10 to 13 become shorter towards the end of the furnace, so that the points of contact change more frequently in the direction of transport.

The fixed beam sections 7, 8, 9 following the first fixed beam section 6 are cranked on one side, so that their end facing the beginning of the furnace passes laterally past the adjacent walking beam sections 10, 11, 12 and so the freedom of movement of the walking beam sections 10 to 13 and the full load capacity of the fixed beam sections 6 to 9 is guaranteed.

The fixed beam sections 6 to 9 and the walking beam sections 10 to 13 alternate with each other in the feed direction in the longitudinal axis.

Both on the continuous fixed beam 4 and walking beam 5 as well as on the fixed beam sections 6 to 9 and walking beam sections 10 to 13, obliquely extending supporting webs 14 are arranged. Due to these inclined supporting webs, a constant migration of the support points of the annealing material during transport through the walking beam furnace 1 is already achieved with the continuous fixed beams 4 and the parallel walking beams 5, so that the temperature difference in the area of the cooling shadows is considerably reduced.

If, in addition, the fixed beam sections 6 to 9 and the walking beam sections 10 to 13 are alternately arranged in the longitudinal axis, an additional compensation of the temperature difference is achieved, since the annealing material rests on the walking beam sections 10 to 13 only during transport, on the fixed beam sections 6 to 9 lingers for a long time.

While in the case of continuous fixed beams 4 and walking beams 5, the angle of the supporting webs 14 to the longitudinal axis can be the same and equally directed, it may be necessary for structural reasons in the arrangement of the supporting webs 14 on the fixed beam sections 6 to 9 and the walking beam sections 10 to 13 provide some consecutive support webs 14 the same or different, but opposite angle to the longitudinal axis, so that adjacent ends of the support webs 14 in this Bump area together.

This makes no significant difference with regard to the temperature compensation in the area of the cooling shade.

As can be seen from FIGS. 2 to 6, the fixed beams 4, the walking beams 5 and the fixed beam sections 6 to 9 and the walking beam sections 10 to 13 consist of horizontal, cooled tubes 15, on the upper side of which an axial longitudinal web 16 is welded. This axial longitudinal web 16 serves as a holder for the supporting webs 14.

Latching projections 17, 18 are welded to the axial longitudinal webs 16 at regular intervals.

The supporting webs 14 have support feet 19, 21 in the end regions and a further support foot 20 approximately in the center. These support feet 19 to 21 overlap the longitudinal web 16, the support foot 19 having lower, lateral extensions 22 which engage under the locking projections 17.

The locking projections 18 are arranged in the region of the central support foot 20 and are in each case on opposite sides of this support foot 20. Thus, the locking projections 17 serve to prevent lifting of the support web 14 from the longitudinal web 16, while the locking projections 18 block a longitudinal displacement of the support web 14.

For assembly, a support web 14 can be placed obliquely with its support foot 19 over the longitudinal web 16 such that it engages over it and can be moved axially until the lateral locking projections 17 are gripped by the extensions 22. If the support web 14 is now completely lowered onto the longitudinal web 16, the support foot 20 reaches the area between the locking projections 18 and is thereby axially fixed. The supporting web 14 is now secured against axial displacement as well as against falling and tipping over from the longitudinal web 16.

In the area of the support foot 21, additional locking projections preventing axial displacement can be arranged.

Each support web 14 has a straight part 23 resting on the longitudinal web 16, which connects the support feet 19, 20, 21 to one another. Parallel end regions 25, 26, which are connected to one another via an inclined intermediate region 27, protrude from one side of the support foot 19 and from the opposite side of the support foot 21. The end regions 25, 26 and the intermediate region 27 form the support part 24 on the support web 14.

It can be seen that the distance between the end region 25 and the end region 26 is approximately in the order of magnitude of the diameter of the cooled tube 15, so that due to the oblique course of the supporting part 24 of the supporting webs 14 there is no increase in the dimensions of the fixed beams 4 and walking beams 5 or 5 the fixed beam sections 6 to 9 and walking beam sections 10 to 13 enter.

The cooling tube 15 can be coated with a highly heat-resistant insulation 28, from which only the supporting part 24 of the supporting webs 14 protrudes, so that the tubes 15 are not excessively heated and the annealing material is cooled only in the area of the bearing surface on the supporting parts 24. This also helps to reduce the temperature difference in the cooling shadow of the annealing material.

Claims (10)

1. A walking-beam furnace including tubes (15) forming cooled fixed beams (4, 6, 7, 8, 9) disposed with their longitudinal axis parallel to the forward stroke direction and tubes (15) forming cooled walking beams (5; 10, 11, 12, 13) disposed with their longitudinal axis parallel to the forward stroke direction and to the fixed beams; longitudinal ribs (16) welded on to the upper sides of the tubes (15); lateral locking projections (17, 18) on the longitudinal ribs; bearer ribs (14) carried on the longitudinal ribs; and supporting feet (19, 20, 21) located on the bearer ribs (14) in the vicinity of their ends and engaging over the longitudinal ribs (16), characterised in that each bearer rib (14) is provided with a supporting foot (20) in the middle and in that one end supporting foot (19) has extensions (22) which can be pushed under the locking projections (17) when the bearer rib (14) is somewhat tilted, the longitudinal rib (16) having in the vicinity of a middle supporting foot (20) and/or of an end supporting foot (19, 21) lateral projections (18) projecting into the vicinity of the supporting surface or surfaces (19, 21) and serving to prevent longitudinal displacement after lowering of the bearer rib (14), and in that the bearer ribs (14) carried on the longitudinal ribs (16) run at an angle to the longitudinal axis of the tubes (15).
2. A walking beam furnace according to claim 1, characterised in that each bearer rib (14) is provided in the vicinity of its ends and in the middle with supporting feet (19, 20, 21) which engage over the longitudinal ribs (16).
3. A walking beam furnace according to claim 1 or claim 2, characterised in that each bearer rib (14) comprises a straight portion (23) lying on the corresponding longitudinal rib (16) and connecting the supporting feet (19, 20, 21) and a bearer portion (24) standing up vertically therefrom and running obliquely from one side of the supporting foot at one end to the other side of the supporting foot at the other end.
4. A walking beam furnace according to claim 3, characterised in that each bearer portion (24) comprises end regions (25, 26) parallel to the longitudinal rib (16) in the vicinity of the end supporting feet (19, 21) and an intermediate region (27) running obliquely and connecting these end regions.
5. A walking beam furnace according to one or more of claims 1 to 4, characterised in that a plurality of successive bearer ribs (14) are fixed to one walking beam (5; 10, 11, 12,13) and/or fixed beam (4; 6, 7, 8, 9).
6. A walking beam furnace according to claim 5, characterised in that the successive bearer ribs (14) are at the same angle to the longitudinal axis and adjacent ends of the bearer ribs (14) along the longitudinal axis are offset from one another.
7. A walking beam furnace according to claim 5, characterised in that the successive bearer ribs (14) are at the same or the oppositely directed angle to the longitudinal axis and adjacent ends of the bearer ribs meet.
8. A walking beam furnace according to one or more of claims 1 to 7, characterised in that both the walking beams and the fixed beams are divided in the feeding direction into sections (6, 7, 8, 9; 10, 11, 12, 13) and walking beam sections and fixed beam sections alternate with one another along the longitudinal axis.
9. A walking beam furnace according to one or more of claims 1 to 8, characterised in that a plurality of successive bearer ribs (14) are located on one walking beam section or fixed beam section (6, 7, 8, 9; 10, 11, 12, 13).
10. A walking beam furnace according to one or more of claims 1 to 9, characterised in that the walking beams and fixed beams (4, 5; 6, 7, 8, 9; 10, 11, 12, 13) and the portion (23) lying thereon are provided with refractory insulation (27) which leaves only the upper region of the bearer ribs (14) free.

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