DE102010006229B3 - Pressurized furnace comprises a melt area and a furnace window in which the flow of melt is controlled through the furnace window over pressure exerted on the melt, and in which a displacer insert is partially arranged in the melt area - Google Patents

Abstract

The pressurized furnace comprises a melt area (12) and a furnace window (22) in which the flow of melt (18) is controlled through the furnace window over pressure exerted on the melt, and in which a displacer insert (32) is partially arranged in the melt area. The displacer insert has a cavity open back to the melt area, where the cavity is filled with a displacement fluid (20). The opening of the cavity in the cross-section to the melt area is greater/same to the diameter of the cavity. The opening of the cavity shows towards bottom. The displacer insert stands on supports in the melt area. An independent claim is included for a method for continuous operation of a pressurized furnace.

Description

The invention relates to a pressure furnace with at least one melting chamber and a furnace window, in which the pressure of melt passing through the furnace solid is controlled via a pressure exerted on the melt, and in which at least partially a displacer insert is arranged in the melting space. The invention likewise relates to a method for the continuous operation of a printing furnace having at least one melting space and one furnace window, in which the melt flow through the furnace window is controlled via a pressure exerted on the melt and in which the melt space is discontinuously filled with melt.

Press furnaces of the type mentioned serve to control the flow of a melt emerging from the furnace window, which is provided, for example, to be filled in one or more of the pressure furnace downstream molds or fed to a continuous casting. Upstream of these pressure furnaces are in this case usually filling devices which are adapted to fill the melting chamber discontinuously with melt. Such a printing oven is for example from the document GB 2 323 804 A known and there part of a melt-supplying device, which is provided for the provision of melt for a downstream filling of a mold by means of a die-casting process. A typical die casting machine for carrying out a die-casting process is known for example from US Pat DE 195 08 867 A1 known.

When from the publication GB 2 323 804 A Known pressure furnace, the provision of a melt flow by immersing a vertically movable displacement body in a melt-filled melt space, so that the melting can be fed through the furnace window finally the casting mold by the associated with the immersion elevation of the melt level in the melt space. Also from the DE 10 2004 056 524 A1 a casting device is known in which a displacement body is used accordingly.

In alternative furnaces, the elevation or regulation of the melt level takes place by supplying a gas displacing the melt. This working principle is for example from the DE 198 32 192 A1 known. In this case, a complex mechanical device for providing a vertically movable displacement body can be dispensed with such that the displacement body is replaced by the gas displacing the melt. However, the melting chamber bounding the inner surface of the pressure furnace wall is exposed by the alternating contact with the gas or to the melt large temperature changes that are associated with severe thermal stresses on the pressure furnace wall, which after a certain period of use to damage and possibly also to Leaks can lead to the pressure furnace wall. In particular, in walls with a complicated geometry of the lining cracks may occur, which hinder the tightness of the vessel or melting space.

Here is a distinction between pressure furnaces, which are operated discontinuously, in which the application of a pressure so usually only a precise and straightforward metering is to serve, and continuously operated pressure furnace in which for a long time a continuous melt flow as possible under uniform conditions should be maintained. In this context, the term "continuous" defines itself from the provision volume of the corresponding printing furnace and the melt volume to be provided for the casting process under constant operating conditions. Insofar as the pressure furnace has to be charged with fresh melt at least twice in order to be able to provide the melt volume to be provided, at least one must speak of a continuously operated pressure furnace.

Other devices that are generally provided for the forwarding or conveying of melt, but operate without a Verdrängseinsatz or a displacing gas for adjusting a melt level, for example, from DE 103 28 654 A1 , of the DE 696 17 174 T2 , of the DE 199 62 471 A1 , of the DE 1 217 558 A and the DE 102 18 958 A1 known.

The invention has for its object to provide a generic printing furnace or a generic method for continuous operation of a printing furnace, in which caused by thermal stress damage to the printing furnace in the vicinity of the melting space can be effectively avoided without complex mechanical equipment must be operated.

This object is achieved with a pressure furnace having at least one melting chamber and a furnace window, in which a pressure exerted on the melt pressure of the passage of melt through the furnace is fixed, in which in the melting space at least partially a displacer is arranged and which thereby characterized in that the displacer insert can be filled with a displacement fluid.

In contrast to known solutions, the invention provides that the displacer insert can be filled with a displacement fluid. The displacement fluid, which z. B. a compressible fluid or gas such. As air, nitrogen or other inert gas, or an incompressible fluid, ie a liquid such. As liquid metals or other high-temperature resistant liquids, can be used according to the invention, the displacement of melt, which is received in the melting space. By filling the displacer insert with the displacement fluid - and the concomitant application of pressure to the melt by means of the displacement fluid - a desired melt level in the melt space is adjustable. By suitable filling of the displacer insert with the displacement fluid or by suitable removal of displacement fluid from the displacer insert, an outflow of melt, in particular metallic melt, from the melt space through the furnace window or an inlet of melt can be compensated by filling the melt space with melt, so that a predetermined melt level can be maintained in the melt space.

By suitable filling of the displacer insert with the displacement fluid or by suitable removal of displacement fluid from the displacer insert, in particular the passage of melt through the furnace solid can be effectively controlled. In particular, it is possible in this way to set a continuous, preferably substantially constant, melt flow, in particular even if the melt space is or can only be filled discontinuously with melt. The pressure furnace according to the invention is therefore particularly suitable, for example, for use in horizontal continuous casting.

In contrast to known solutions comes by filling the displacer insert with the displacement fluid only the displacer cartridge with the displacement fluid in contact. An inner surface of the wall of the press furnace which delimits the melting space is therefore not exposed to an alternating contact with the displacement fluid or the melt under suitable circumstances or with suitable process control, in contrast to known solutions. As a result of this changing contact caused temperature changes that are associated with strong or large thermal stresses on the wall of the printing furnace, u. U. be effectively avoided by means of the displacer insert. In this way, damage to the printing furnace in the vicinity of the melting space can be avoided accordingly, in particular leaks on the wall of the printing furnace, or the occurrence of such damage can be delayed accordingly. Although then, instead of the wall of the printing furnace, the displacer insert is exposed to strong thermal stresses as a result of the alternating contact with the displacement fluid or melt. However, the displacer insert, which preferably consists at least partially or entirely of clay graphite or SiC or similar suitable materials, can be easily replaced. Long downtimes, which are required for repair of known pressure ovens after damage to the furnace in the vicinity of the melting space, are effectively avoided in this way. Preferably, the displacer insert can be designed in the form of a prefabricated crucible and therefore be provided in particular as an exchangeable purchased part. Also, depending on the specific embodiment, the displacer can be specially designed to optimize its task, since he otherwise has no other tasks, such as a supporting function to meet.

Preferably, the displacement of melt takes place by filling with the displacement fluid, so that expensive mechanical devices for moving a known displacer insert into or out of the melt can be omitted, along with a very practical and easy handling and operability of the printing oven according to the invention ,

The displacer insert is at least partially or completely or entirely arranged in the melting space and projects beyond the melting space only with a filling opening, through which displacement fluid can be provided. In this case, the displacer insert can be covered by melt except for the filling opening and / or a corresponding feed line even in certain operating situations, for example during continuous operation, whereby the thermal load on the displacer insert can be minimized.

The displacer insert particularly preferably has a cavity which is open toward the melting space and which can be filled with displacement fluid, wherein the opening of the cavity preferably faces downwards or is preferably oriented vertically. Such a trained displacement insert can be filled in a simple manner with the displacement fluid and can also be finished in a simple and cost-effective manner, so that it can be made available in particular as a cost-effective purchased part or spare part. In particular, the displacer insert may have an outer surface in the form of a cylinder jacket surface of a cylinder with a circular or rectangular or square base surface. Such a trained Verdrängerereinsatz has a high stability to thermal stresses, and it is therefore a variety of different materials conceivable from which the displacer insert can be made.

Preferably, the opening of the cavity in cross-section is greater than or equal to the diameter of the cavity. This design effectively avoids adverse formation of solidified fuses within the cavity due to undercuts. It is particularly preferred in this case if the cavity is designed in the form of a truncated cone whose largest base surface is identical to the surface of the opening of the cavity or the opening surface of the cavity.

In a practical embodiment, the displacer insert stands on supports in the melting space. In this way, the displacer insert can be conveniently placed at a fixed position at least partially or entirely within the melt space. In particular, can be dispensed with further supporting devices for the displacer insert with a suitable design.

Also proposed as a solution for a continuous operation of a printing furnace with at least one melting chamber and a furnace window, wherein the melt flow through the furnace window controlled by a pressure exerted on the melt and in which the melt space is discontinuously filled with melt, wherein the melt flow through controlling a displacer insert having a cavity open to the melt space, which is filled with displacement fluid to receive melt flow or receives melt. In continuous pressure furnaces, the use of displacers, which were previously used only for accurate metering, is not known. However, the use of positive displacement inserts can also effectively prevent damage to the printing furnace in the vicinity of the melting space caused by thermal stresses during continuous operation and a uniform melt flow can be provided.

In an alternative embodiment, the displacer insert in the melting chamber is vertically displaceable here, whereby a simple and effective, depending on the concrete implementation of the present invention, on the one hand displaces a corresponding volume and / or on the other hand easy maintenance can be ensured.

Due to the fact that the displacer insert has a cavity which is open towards the melt space and which is filled with displacement fluid or receives melt for controlling the melt flow, on the one hand a very exact metering of the melt flow and on the other hand the conservation of the printing furnace itself or its wall already explained in detail allows.

As already explained above, when the displacer insert is filled with the displacement fluid, essentially only the displacer insert comes into contact with the displacing fluid. In contrast to known solutions, an inner surface of the wall of the press furnace or areas in the vicinity or adjoining surroundings of the melt space delimiting the melt space are not exposed to an alternating contact with the displacement fluid or the melt, accompanied by an effective avoidance of damage and possibly Also leaks at the pressure furnace in the vicinity or adjacent environment of the melting chamber.

It is understood that the features of the solutions described above or in the claims can optionally also be combined in order to implement the advantages in a cumulative manner.

Further advantages, objects and characteristics of the present invention will be explained with reference to the following description of the appended drawings. In the drawing show:

1 a schematic sectional view of a first embodiment of a printing furnace according to the invention;

2 a schematic sectional view of a second embodiment of a printing furnace according to the invention;

3 a schematic sectional view of a third embodiment of a printing furnace according to the invention;

4 a schematic sectional view of a fourth embodiment of a printing furnace according to the invention; and

5 a schematic sectional view of a printing furnace according to the prior art.

The in 5 illustrated known printing furnace 10 The prior art has a contiguous melting space 12 on, the three over two channels 14 interconnected chambers 16 includes. The melting chamber 12 is in operation partially with a melt 18 refilled. Through one on the melt 18 exerted gas pressure P, the gas 20 is preferably air, can in this known pressure furnace 10 the passage of melt 18 through a stove window 22 by appropriate lifting or lowering of the melt level 24 to be controlled. This allows in particular a discontinuous filling of the printing furnace 10 without the continuous melt flow of the melt 18 through the oven window 22 must be changed significantly, with an unnumbered heating, which around the channel 14 is arranged, which the the furnace window 22 comprehensive chamber 16 with the remaining melting space 12 connects, a temperature of the melt can be made. The the melting chamber 12 limiting inner surface 26 the wall 28 of the printing furnace 10 is due to the alternating contact with the gas or to the melt in the middle chamber 16 exposed to large temperature changes, there with strong thermal stresses on the wall 28 which, after a certain period of use, leads to damage and possibly also to leaks on the wall 28 being able to lead. Overall, can be in this known pressure furnace 10 after a certain period of operation damages and / or leaks in the printing furnace 10 in environment or adjacent environment of the melting space 12 not avoid.

The 1 shows a first embodiment of a printing furnace according to the invention 30 , Unlike the in 5 shown known printing furnace 10 has the in 1 illustrated printing furnace according to the invention 30 partly in a melting room 12 arranged displacement insert 32 on, the one of the melting space 12 limiting inner surface 26 the wall 28 of the printing furnace 30 is spaced. Again, there is an unnumbered heating for the heating or temperature control of the melt 18 intended.

The coherent melting chamber 12 includes three via two channels 14 interconnected chambers 16 , The displacer insert 32 points you to the melting space 12 open cavity 34 up, over an opening 44 of the displacer insert 32 that are different from outside the repressive use 32 up to the cavity 34 extends, with a displacement fluid 20 is fillable. As a displacement fluid 20 In the present case, a gas, preferably air, is provided. The opening 36 of the cavity 34 in the present case downwards, so it is aligned lotecht. Through one on the melt 18 exerted gas pressure P or air pressure P, the passage of melt 18 through a stove window 22 be controlled by appropriate lifting or lowering of the melt level. In particular, in this way a continuous, preferably substantially constant melt flow can be set, in particular even if the melting space 12 only discontinuously via a hopper 38 with melt 18 is filled. The illustrated pressure furnace 30 is therefore particularly suitable for the production of a continuous casting profile 40 ,

Unlike the in 5 shown known printing furnace 10 comes through the filling of the displacer insert 32 with the gas 20 only the displacement insert 32 with the gas 20 in contact. The inner surface 26 the wall 28 of the printing furnace 30 thus will not be an alternating contact with the gas 20 or the melt 18 exposed. As a result of this changing contact caused temperature changes, the area with strong or large thermal stresses on the wall 28 of the printing furnace 30 be accompanied by the displacement insert 32 effectively avoided. Overall, this can damage the printing oven 30 in the vicinity of the melting space 12 effectively avoided, in particular leaks on the wall 28 of the printing furnace 30 , along with ensuring tightness and improving reliability of operation and pressure tightness. The place of the wall 28 of the printing furnace 30 highly thermally stressed displacement insert 32 can be easily replaced if necessary. Long downtimes for repair are effectively avoided in this way. Also, its wall can be readily configured optimized for this stress, since this wall otherwise has no other tasks to fulfill.

The 2 shows a second embodiment of a printing furnace according to the invention 30 , Unlike the in 1 illustrated embodiment, this printing furnace according to the invention 30 a coherent melting chamber 12 on, the only two over a channel 14 interconnected chambers 16 includes. As a result of the provision according to the invention with a displacement fluid 20 fillable displacer insert 32 can the number of chambers 16 compared to the in 5 shown known printing furnace 10 be reduced because of the inclusion of the displacement fluid 20 no separate chamber or room has to be provided. The displacer insert 32 can be independent of the wall 28 or lining up 28 of the printing furnace 30 in the printing oven 30 to be placed. So it is possible, the pressure furnace according to the invention 30 unlike the known solution to make much more space-saving or more compact, as from 2 seen.

The 3 shows a third embodiment of a printing furnace according to the invention 30 , which has a coherent melting space 12 also only two over a channel 14 interconnected chambers 16 includes. In this embodiment, the in 1 illustrated right outer partition 42 , which is the right chamber 16 from the middle chamber 16 separates, waives, to an overall increase in the available melting space 12 to accomplish with constant outside dimensions.

At the in 4 illustrated fourth embodiment of a printing furnace according to the invention 30 is a coherent melting chamber 12 provided, the only one chamber 16 includes, so that in 4 illustrated printing furnace according to the invention 30 a melting chamber 12 has a large volume and is also designed to be compact or space-saving.

While the in 3 illustrated arrangement a channel 14 which is surrounded by a heater, this look after the arrangements 2 and 4 not before. However, if necessary, in the case of the latter exemplary embodiments, a per se known dummy channel may be provided on which a corresponding heater is arranged. It is understood that other known from the prior art heating devices can be provided accordingly.

LIST OF REFERENCE NUMBERS

10

Druckofen-state of the art

12

melt space

14

channel

16

chamber

18

melt

20

Gas or air

22

oven window

24

melt level

26

palm

28

wall

30

Printing oven according to the invention

32

Displacement insert

34

cavity

36

Opening cavity

38

hopper

40

Extruded section

42

partition wall

44

Opening displacer insert

Claims (7)

Pressure furnace with at least one melting chamber ( 12 ) and a furnace window ( 22 ), in which one on the melt ( 18 ) pressure exerted the passage of melt ( 18 ) through the oven ( 22 ), and in which in the melting space ( 12 ) at least partially a displacement insert ( 32 ), characterized in that the displacer insert ( 32 ) with a displacement fluid ( 20 ) is fillable. Pressure furnace according to claim 1, characterized in that the displacer insert ( 30 ) one to the melting space ( 12 ) open cavity ( 34 ) which is filled with displacement fluid ( 20 ) is fillable. Pressure furnace according to claim 2, characterized in that the melting space ( 12 ) pointing opening ( 36 ) of the cavity ( 34 ) in cross-section greater than or equal to the diameter of the cavity ( 34 ). Pressure furnace according to claim 2 or 3, characterized in that the opening ( 36 ) of the cavity ( 34 ) points downwards. Pressure furnace according to one of claims 2 to 4, characterized in that the displacer insert ( 32 ) on supports in the melting space ( 12 ) stands. Method for the continuous operation of a printing furnace ( 30 ) with at least one melting space ( 12 ) and a furnace window ( 22 ), in which the melt flow through the furnace window ( 22 ) over one on the melt ( 18 ) pressure exerted and in which the melting space ( 12 ) discontinuously with melt ( 18 ), characterized in that the melt flow through a displacement insert ( 32 ), which leads to the melting space ( 12 ) open cavity ( 34 ), which is used to control the melt flow with displacement fluid ( 20 ) or melt ( 18 ). Method according to claim 6, characterized in that the displacer insert ( 32 ) in the melting space ( 12 ) is vertically displaceable.

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