EP1077357B1 - Cooling element - Google Patents

Abstract

Cooling element has cooling channels (2) into which stoppers (8) are slid to form a channel string with an inlet (5) and an outlet. The stoppers have concave deviating surfaces (12) facing the cooling channels. Preferred Features: The deviating surfaces have a spherical section shape. The radius (RU) of the deviating surfaces are twice as large as the radius (RK) of the cooling channels. The cooling element is made of copper or a low-alloyed copper alloy.

Description

The invention relates to a cooling element for melting furnaces, which is penetrated by coolant channels introduced by mechanical deep drilling.

Such cooling elements are interchangeable components of an inner cladding of a melting furnace. Since the temperature prevailing in the melting furnaces is above the melting temperature of the cooling elements, cooling is necessary in order to prevent the cooling elements from softening. The cooling elements are often made of gray cast iron or steel.

It is state of the art to cast cooling pipes in cast iron cooling elements. This has the disadvantage that an oxide layer surrounding the cooling tubes or an air gap complicates the heat transfer to the coolant. In addition, cast iron cooling elements have a relatively low thermal conductivity.

Copper and copper alloys have significantly better thermal conductivities than gray cast iron. In this context, DE 29 07 511 C1 discloses a cooling element for shaft furnaces, which consists of copper or a low-alloy copper alloy and is made from a forged or rolled ingot. In this type of construction there are coolant channels generated by mechanical deep drilling in the interior of the cooling element, which run vertically in the position of use. The blind holes drilled in the cooling element are sealed by soldering or welding in threaded plugs. On the back of the cooling element there are inlet bores to the coolant channels, into which the connections required for the coolant supply or coolant discharge are welded or soldered.

In order to be able to divert the cooling liquid within the cooling element, the blind bores are usually introduced into the cooling element at an angle of 90 ° to one another. If a transverse bore penetrates several longitudinal bores, plugs must be inserted between two crossing areas of the bores for the controlled diversion of the coolant flow. These areas of intersection are fluidically unfavorable.

In the coolant line passing through the cooling element, energy losses along the current filament occur due to shear stresses in the coolant. In the case of laminar flow, the particles of the coolant move in parallel paths, while in the case of turbulent flow, additional velocities in the X, Y and Z directions overlap the main flow, which leads to eddy formation. While the pressure loss increases linearly with speed in laminar flow, it increases quadratically with speed in turbulent flow. Turbulence occurs especially on discontinuous cross-sectional enlargements, e.g. in intersection areas of the coolant channels. As the flow rate increases, much more powerful pumps are required.

The increased flow resistance within deep-drilled cooling elements can mean that a pump system, which is sufficient when using cooling elements with cast-in coils, must be replaced by a more powerful pump system when installing deep-drilled cooling elements.

Starting from the prior art, the invention is based on the object of providing a cooling element for melting furnaces which is improved with regard to the flow resistance within the coolant channels.

The invention solves the problem by the features specified in the characterizing part of claim 1.

In the cooling element according to the invention, the plugs have deflection surfaces of certain configurations facing the coolant channels. These are designed so that the cross-sectional change in the penetration area of two coolant channels is reduced. A concave deflection surface gently redirects the flow. This prevents an abrupt braking of the coolant flow and reduces friction losses in the penetration area.

Deflection surfaces designed in the form of spherical sections are particularly advantageous, since the coolant channels introduced by mechanical deep drilling have a circular cross section.

A constant cross section of the channel line is obtained in particular when the radius of the deflection surfaces in the penetration area of two coolant channels corresponds to the diameter of the coolant channels (claim 3).

The advantages of the invention are equally given when the radius of the deflection surfaces corresponds to the radius of the coolant channels (claim 4). This embodiment has advantages in terms of production technology, since the deflecting surfaces can be produced particularly easily with a suitable ball milling cutter.

In the context of the embodiment of claim 5, the deflection surfaces are arranged between two transition openings offset by 90 ° to one another. The transition openings preferably have the same diameter as the adjacent coolant channels in order to avoid changing the cross section of the channel line.

The plug having an angular transition channel is therefore somewhat larger in outside diameter than the inside diameter of the coolant channels. In this embodiment, the features of claim 4 in particular to wear, whereby a ball mill can be inserted into the stopper through the transition openings, which forms the deflection surface. The radius of the deflection surface is thus determined by the radius of the ball mill, which in turn is dependent on the diameter of the transfer openings or the coolant channels.

Of course, within the scope of the invention, configurations are also conceivable in which the transition openings are not offset by 90 ° to one another, but are at any acute or obtuse angle to one another.

According to claim 6, two opposite end faces of a stopper are formed by deflecting surfaces. Such a plug is used in the interior of a cooling element in which the coolant channels are arranged, for example, in a meandering manner. Due to the manufacturing process, mutually penetrating coolant channels are introduced into the cooling element. To form the meandering shape, individual coolant channels must be closed in sections by plugs. The length of the stopper is predetermined by the distance between the intersections of the coolant channels.

According to the features of claim 7, two deflecting surfaces form the ends of an elongated trough formed in a stopper. This embodiment is used when the coolant channels introduced by deep drilling are to be connected to one another in the region of an end face of the cooling element. For this purpose, a recess adapted to the stopper is made in the cooling element and a recess between the coolant channels which, together with the trough of the stopper, forms a transfer channel for the coolant. This transfer channel preferably has the same cross section as the coolant channels. For this purpose, the elongated trough between its ends is shaped like a cylinder section. The radius of the cylindrical central section preferably corresponds to the radius of the coolant channels and the radius of the recess. manufacturing technology the recess can be produced particularly easily with a ball milling cutter which at the same time forms the deflecting surfaces at the ends and forms the cylindrical central section of the stopper between the ends by a linear method.

The plugs are tightly fitted into the coolant channels according to the features of claim 8. For example, they can be clamped in the coolant channels by external influences (material compression). There are also locking rings that are held in an outside groove in the stopper and press resiliently against the walls of the coolant channels.

According to claim 9, the plugs are welded, soldered and / or screwed into the coolant channels. The additional integral connection of the plugs fitted into the coolant channels secures them against falling out even under rough operating conditions and enables fluid-tight fixing without additional sealing elements.

According to the features of claim 10, the cooling element consists of copper or a low-alloy copper alloy. The cooling element is preferably forged or rolled from a raw block of copper or a low-alloy copper alloy. Cooling elements produced in this way have a denser and more homogeneous structure than cast copper elements and have a higher strength and thermal conductivity.

The present invention makes it possible to use pump systems with a lower output, as a result of which the installation outlay when changing from cooling elements made of steel or cast iron to copper cooling elements can be considerably reduced.

Figur 1

einen Ausschnitt eines mit einem Stopfen versehenen Kühlmittelkanals eines Kühlelements im Querschnitt im Bereich eines Stutzens;

Figur 2

in vergrößertem Maßstab eine perspektivische Darstellung des Stopfens der Figur 1;

Figur 3

eine weitere Ausführungsform eines einen Kanalstrang abschnittsweise verschließenden Stopfens im Querschnitt;

Figur 4

ebenfalls im Querschnitt eine dritte Ausführungsform eines Stopfens im Verlauf eines Kanalstrangs;

Figur 5

eine Schnittdarstellung entlang der Linie V-V in Figur 4 und

Figur 6

in der Vergrößerung eine perspektivische Darstellung des Stopfens gemäß Figur 4.

The invention is explained in more detail below on the basis of exemplary embodiments schematically illustrated in the drawings. Show it:

Figure 1

a detail of a coolant channel provided with a plug of a cooling element in cross section in the region of a nozzle;

Figure 2

on an enlarged scale a perspective view of the plug of Figure 1;

Figure 3

a further embodiment of a plug closing a channel strand in sections in cross section;

Figure 4

likewise in cross-section a third embodiment of a plug in the course of a channel line;

Figure 5

a sectional view taken along the line VV in Figure 4 and

Figure 6

4 shows an enlarged perspective view of the stopper according to FIG. 4.

FIG. 1 shows a corner region of a cooling element 1 in section with a coolant channel 2 running in the longitudinal direction of the cooling element 1. The cooling element 1 is traversed by a plurality of coolant channels 2, not shown in detail, which form a continuous channel line in the cooling element 1.

The coolant channel 2 is introduced into the cooling element 1 by mechanical deep drilling from the end 3 thereof. To supply the channel line with a coolant, the cooling element 1 is provided with a coolant inlet 5 on its side 4 facing away from the interior of a melting furnace (not shown in detail). For this purpose, the coolant channel 2 has an inlet bore 6 which is introduced from the side 4 and into which a pipe socket 7 is firmly inserted. The pipe socket 7 can be welded or soldered into the inlet bore 6. Through the inlet hole 6 is in the coolant channel 2 a plug 8 inserted. The stopper 8 has a first transition opening 9 facing the coolant channel 2 and a second transition opening 10 which faces the pipe socket 7 of the coolant inlet 5 offset by 90 °. Coolant can thus flow through the coolant inlet 5 and through the plug 8 into the coolant channel 2. The plug 8 is welded from the end 3 of the cooling element 1 to the wall 11 of the coolant channel 2.

Between the staggered transfer openings 9, 10, the plug 8 has a deflection surface 12 facing the coolant channel 2 and the coolant inlet 5. It is clear from FIG. 2 that the deflection surface 12 is designed in the form of a spherical segment. The radius R _{U of} the deflection surface 12 corresponds to the radius R _{K of} the coolant channel 2. The radius R _{D of} the transfer openings 9, 10 corresponds to the radius R _{K of} the coolant channel 2 and the coolant inlet 5. The plug 8 and the pipe socket 7 have the same outside diameter D _A , which is matched to the diameter D _{Z of} the inlet bore 6.

In the embodiment according to claim 3, a plug 13 is arranged in a horizontal coolant channel 14 in the interior of the cooling element 1. A first and a second vertically extending coolant channel 15, 16 open into the horizontal coolant channel 14 at a parallel distance from one another. The longitudinal axes of the vertical coolant channels 15, 16 intersect at a first intersection point SP ₁ and a second intersection point SP ₂ with the longitudinal axis of the horizontal coolant channel 14th

The plug 13 extends between these intersections SP ₁ and SP ₂ in the horizontal coolant channel 14. In this case, its end faces facing away from one another are designed as deflecting surfaces 17 in the form of spherical sections. The radius R _{U of} the deflection surfaces 17 corresponds to the radius R _{K of} the coolant channels 14, 15, 16. Through the deflection surfaces 17, a coolant, as indicated by the arrows PF, is directed from the horizontal coolant duct 14 into the vertical coolant duct 15 and from the vertical one Coolant channel 16 again in the horizontal coolant channel 14.

The two coolant channels 15, 16 can also be connected at the other end, as shown in FIG. 3, or they can be connected to one another in accordance with FIG. 4 (explained in more detail below).

The plug 13 is fixed locally by an annular fastening element 18 arranged in its central longitudinal section. The fastening element 18 clamps the plug 13 to the wall 19 of the horizontal coolant channel 14. A securing ring held in a groove in the plug 13, for example, is suitable as the fastening element 18.

In the context of the embodiment in FIGS. 4 to 6, two coolant channels 21, 22 which run parallel to one another are connected to one another in a fluid-conducting manner by a plug 20. The plug 20 extends between the coolant channels 21, 22 and is inserted into a groove from the end face 21 of the cooling element 1. It is designed in the manner of a feather key and rounded at the end, its side facing the coolant channels 21, 22 being designed as an elongated trough 24 with a cylindrically recessed central section 26 and end-side concave deflection surfaces 25 (FIG. 6). The radius R _{U of} the deflecting surfaces 25 in turn corresponds to the radius R _{K of} the coolant channels 21, 22. The same applies to the radius R _{M of} the cylindrical central section 26 of the trough 24. To avoid a cross-sectional constriction in the region of the cylindrical central section 26, one with the latter corresponding cylindrical recess 27 arranged in the cooling element 1. As a result, an overflow channel 28 of the same cross section is formed between the coolant channels 21, 22.

REFERENCE NUMBERS

1 -

cooling element

2 -

Coolant channel

3 -

End of v. 1

4 -

Page v. 1

5 -

Coolant inlet

6 -

inlet bore

7 -

pipe socket

8th -

Plug

9 -

Transfer opening v. 8th

10 -

Transfer opening v. 8th

11 -

Wall v. 2

12 -

deflection

13 -

Plug

14 -

horizontal coolant channel

15 -

vertical coolant channel

16 -

vertical coolant channel

17 -

Deflecting surface v. 13

18 -

Fastening element v. 13

19 -

Wall v. 14

20 -

Plug

21 -

Coolant channel

22 -

Coolant channel

23 -

Front of v. 1

24 -

Mulde v. 20

25 -

Deflecting surface v. 20

26 -

Middle section v. 20

27 -

Recess in 1

28 -

overflow

D _A -

Outer diameter of 7, 8

D _Z -

Inner diameter of 6

PF -

arrow

R _D -

Radius of 9, 10

R _K -

Radius of 2, 14, 15, 16, 21, 22

R _U -

Radius of 12, 17, 25

R _M -

Radius of 26

SP1

intersection

SP2

intersection

Claims (10)

1. Cooling element for smelting furnaces which is traversed by coolant channels (2, 14, 15, 16; 21, 22) introduced by mechanical deep drilling, into which stoppers (8; 13, 20) are incorporated in sections to form a continuous channel line with at least one coolant inlet (5) and at least one coolant outlet, characterised in that the stoppers (8; 13, 20) have concave deflection faces (12; 17; 25) facing the coolant channels (2; 14, 15, 16; 21, 22).
2. Cooling element according to claim 1, characterised in that the deflection faces (12; 17; 25) are spherical segment-shaped in design.
3. Cooling element according to claim 1 or 2, characterised in that the radius (R_U) of the deflection faces (12; 17; 25) is twice as large as the radius (R_K) of the coolant channels (2; 14, 15, 16; 21, 22).
4. Cooling element according to claim 1 or 2, characterised in that the radius (R_U) of the deflection faces (12; 17; 25) corresponds to the radius (R_K) of the coolant channels (2; 14, 15, 16; 21, 22).
5. Cooling element according to any one of claims 1 to 4, characterised in that the deflection faces (12) are arranges between two overflow apertures (9, 10) offset by 90° with respect to one another.
6. Cooling element according to any one of claims 1 to 4, characterised in that the deflection faces (17) form two end faces of a stopper (13) remote from one another.
7. Cooling element according to any one of claims 1 to 4, characterised in that two deflection faces (25) form the ends of an elongated trough (24) recessed in a stopper (20).
8. Cooling element according to any one of claims 1 to 7, characterised in that the stoppers (8; 13; 20) are fitted tightly into the coolant channels (2; 14; 21, 22).
9. Cooling element according to any one of claims 1 to 8, characterised in that the stoppers (8; 13; 20) are welded, soldered and/or screwed into the coolant channels (2; 14; 21, 22).
10. Cooling element according to any one of claims 1 to 9, characterised in that it consists of copper or any low-alloy copper alloy.