DE4033893C1 - - Google Patents

Description

The invention relates to a multi-purpose furnace for heat treatment of metallic workpieces, with an antechamber that with a protective gas can be acted upon with a closable Heating chamber in which the metallic workpieces of a heat act, in particular a thermochemical treatment be subjected to at least one cooling chamber for cooling the treated workpieces, as well as with a transport device for transporting the workpieces between the chambers.  

Such a multi-purpose oven is from the company brochure "W 02 A, multipurpose oven "from the applicant in 1987.

The multi-purpose furnace known from it has a prechamber, via a feed lockable with a door opening is provided. To load the multi-purpose oven the workpieces in the form of a batch on a charging table brought in front of the loading opening and from the charging table transferred to the antechamber. After closing the loading door and purging the prechamber with an inert gas becomes the batch transferred into the heating chamber by means of a transport device. The fact that in the antechamber by the inert gas purging oxygen-free atmosphere could be achieved at Transferring the batch from the antechamber to the heating chamber, in which the protective gas atmosphere also prevails, none Change in the gas atmosphere in the heating chamber instead. The occurrence mer therefore acts as a lock between the oxygen-containing Environment of the multi-purpose oven and the heating chamber.

After transferring the batch into the heating chamber using the Transport device this is again from the heating chamber driven, the latter closed and then the batch heated in the closed heating chamber. Depending on the desired th type of heat treatment can only be a heating of the Batch. It can also be in the heating chamber at the same time other gases are introduced, which are in the heating chamber with the metallic workpieces react, their surface is remunerated. These are thermochemical treatments under the names carburizing, embroidery or nitriding and nitrocarboration became known. When carburizing the outer layers of the metallic materials with carbon,  when embroidering with nitrogen and when nitrocarburizing both enriched with nitrogen as well as carbon.

After finishing the heat treatment in the heating chamber, opened and the transport device moves into the still hot Heating chamber and transfers the batch, still in glowing Condition from the heating chamber to the cooling chamber so that the batch can be subjected to a cooling process. Mostly it will Cooling performed in a quench bath in which the approximately 1000 ° C hot batch is immersed very quickly. The deterrent bad contains oil (approx. 100 ° C) or a molten salt (approx. 300 ° C). After the cooling process has ended, the batch is restored raised from the quench bath and after draining over the Antechamber extended out of the multi-purpose oven.

In some heat treatment processes, cooling takes place not in a quench bath, but in one with a cooling gas loadable cooling chamber. Quenching in an oil bath or the cooling process in the cooling chamber take place in Protective gas atmosphere so that oxidation processes are excluded are.

The transport device, which is intended for the batch from the antechamber into and out of the heating chamber like the one to be transported consists of one, in one ge closed channel, back-stiff link chain, the the batch pushes or pulls over sliding surfaces. Sliding surfaces are therefore used because in the heating chamber at the high temperatures no bearings can exist.  

The cold batch is transferred from the antechamber to the heating chamber inserted or pushed in by means of the link chain the frictional forces between the corresponding sliding surface the prechamber or the heating chamber and which rest on it the area of the batch can be overcome. With the still cold Batch need to be, for example, a batch of one weight from 1 to push over, forces that are about Correspond to 600 kg. That is, the sliding factor is approximately in the range from 0.6. When transferring the heated batch from the heating comb mer in the antechamber or cooling chamber must be much higher Forces are exerted because the sliding factor is then approximately in Is in the range of 1, i. H. for a 1 to heavy batch the rigid chain link from the heating chamber into the Pushing the prechamber over, forces of 1000 kg are necessary correspond.

A disadvantage of the multi-purpose oven of the type mentioned is that for moving heavy batches very high forces are necessary, which have a correspondingly complex construction make the transport device necessary. In practice it has have shown that a multi-purpose oven of the aforementioned Kind with the stiff link chain transport device for batch sizes in the range of 1 to and larger, no longer used with reasonable design effort can be. Even with batch weights in sizes of 1 to requires considerable constructive effort to move the batches using the rigid chains. These are due to the mechanical bean that occurs exposed to very high wear, so that such a multi-purpose furnace for batches in the range of 1 to and heavier is not functional in the long run.  

Very voluminous and very heavy batches should be heat treated are, for example, large gears with 1 to 2 m in diameter water, shafts, pinions, rotor and stator plates from thermal power mechanical engineering, it is known, this in so-called vertical stoves.

Such a vertical furnace is from the company brochure "W 12 A" Applicant known from 1982.

The vertical retort furnaces shown in it, also called Vertical shaft furnaces are usually hollow cylindrical body with a solid closed bottom on. The hollow cylindrical body is on its upper side provided with a cover that can be used for loading or Emptying the oven can be pivoted sideways. The Batch to be heat treated is inserted into the oven from above using a hoist. After extending the hoist and after closing the lock cover, the interior of the furnace is flushed out with protective gas and then the heat treatment process is carried out. The The interior of the furnace is therefore both antechamber and heating chamber.

After the heat treatment process is complete, the lid is removed opened and the still glowing or hot batch by means of Elevators lifted out of the furnace in the vertical direction and fed to a quench bath in an air atmosphere. Even if the quenching bath right next to the vertical shaft furnace it still takes a few minutes for the Manhole cover is open, the batch is gripped by the hoist is lifted vertically out of the oven and to the quenching bath is proceeded. By transferring in the air atmosphere  find oxidation processes on the batch still hot up to 1000 °. For example wise found that such oxidation processes crack Formations occur on the gears, which then operate to break the entire gear or individual teeth can lead. The fact that the batch with ambient air of about room temperature comes into contact with heat exchange, can individual edge areas compared to internal areas Cool so far that tension or distortion in the workpieces occur.

Batches can be made with the vertical shaft furnaces mentioned above in the range of 10 tons and more in a single heat treatment be treated, the batches dimensions of can have several meters of height, width and depth the atmospheric oxygen contact between transfer from the heater chamber to the cooling chamber or to the quench bath and cooling the aforementioned ones occur during the delivery Disadvantages.

The object of the present invention is therefore to remedy this create and a multi-purpose oven of the type mentioned to develop in such a way that very large and heavy batches, especially in the range of a ton and heavier, heat can be traded, in particular a simple and rapid transfer to and from the heating chamber can be achieved should.

According to the invention the object is achieved in that the Transport device a horizontally and vertically movable, Has crane arranged in the antechamber.  

The object of the invention is therefore completely achieved because by means of a crane also very heavy and large loads can be moved with little friction, in any case significantly less friction than by moving with stiff links chains. Due to the horizontal and vertical displaceability the crane can be placed inside the furnace, i.e. at the end of the necessary transport in the oxygen-containing air atmosphere make movements, d. H. grasping, lifting, Lowering and moving the batch. The vertical shift availability, the batch, hanging on the crane, very quickly, For example, in a quench bath, lower it and out again to lift this. Because the crane is in the antechamber is arranged in which, compared to room temperature, compared to the heating chamber, however, relatively low temperatures prevail (approx. 200 °) and only the protective gas atmosphere prevails, the rotating ones on a crane can and running parts, such as wheels, rollers and cables, permanently remain ready for operation because they do not have a high temperature are exposed to and not with the carburizing nitriding or nitrocarburizing atmospheres in contact come. During the heat treatment process in the heating chamber the crane can operate in the relatively cold zone (approx. 200 ° C) of the furnace remain. The only need to remove the hot batch Crane, after opening the heating chamber, as far as possible, that he can take the batch. This can be done very easily and done very quickly. The voluminous and heavy batch can through the approx. 200 ° warm prechamber filled with protective gas are fed to the cooling chamber without oxidation processes take place or the batch cools so far that a delay takes place on the large workpieces. The latter is particularly especially through the closed system with the opposite  Room temperature increased temperature reached. After cooling the heat-treated batch can then be opened in the multi-purpose furnace and the batch is removed. The entire treatment Processes take place in the interior of the multi-purpose oven in the Protective atmosphere instead, so that oxidation processes with the disadvantageous cracking can be excluded.

In a further embodiment of the invention, the crane a horizontally movable trolley, which is fixed with a vertically extending guide is connected along the one vertically movable workpiece carrier is attached.

This measure has the advantage of being very robust with a few and stable constructible components the essential Lichen parts of the crane can be manufactured. The trolley, through a suitably stiff and stable frame, for example by welding appropriately stiff Carriers, can be constructed very simply, weights in the Range of 10 tons without particularly constructive expenses move horizontally. The one running vertically on the trolley Guidance can then be made appropriately robust, i.e. vertically extending beams welded to the trolley, on which a workpiece carrier is movably attached. The Workpiece carrier can then be designed as a boom at the same time be so that it acts as a carrier during transport and to Set down or grab the batch to be transported. This is also in again by means of simple construction robust construction.

In a further embodiment of the invention, the trolley is via at least one arranged in the interior of the multi-purpose oven  Traction element horizontally reciprocable, at least that a tension element itself over an outside of the interior of the multi-purpose furnace arranged drive is driven.

This measure has the advantage that in the interior of the furnace only the traction element is provided that the trolley moved horizontally back and forth. The real drive, like Electric motors including the necessary wiring arranged outside the interior so that these components the approximately 200 ° hot protective gas atmosphere and also that Quenching process are not exposed to vapors. This also contributes to the robustness, simplicity and life duration of the drive device.

In a further embodiment of the invention, the tension element as an endless element, especially as an endless link chain trained, which runs around two fixed roles, one being driven roller with a gas-tight through a wall of the furnace guided shaft is connected to a drive shaft of the drive arranged outside the furnace is connected.

This measure has the advantage that le in the interior of the furnace diglich the circumferential element is arranged, for example be trained as a very robust metal link chain can. The one driven roller around which the chain runs is via easy-to-implement, gas-tight bearings through a wall of the furnace and with those located outside the interior Drive elements or the power supply connected.

In a further embodiment of the invention, the work hangs piece carrier via a first loose roll attached to it  a lifting element, in particular in the form of a chain that over two on either side of the loose roll, at the top of the Guide arranged fixed roles runs.

This measure has the advantage that robust construction the necessary vertical movement of the workpiece carrier is accomplished. Through appropriately robust training of the lifting element as a link chain, it is possible Keep batches of 10 tons and more safely and also in verti move up and down the calender direction. Training the on hanging the workpiece carrier as a loose roll between the two fixed rollers at the top of the vertical guide, allowed despite being robust and stable, a very fast one Lowering the workpiece carrier, which is particularly important when sinking the batch into a quench bath is desired. For example wise a heat meter, standing vertically for several meters delt workpiece are immersed in the quenching bath, so must this can be done within seconds to ensure that is that there is no warpage within the workpiece that a first lower, already immersed part cools down, whereas an upper one, not yet in the quench bath immersed part is still very hot.

In a further embodiment of the invention, the hub Element arranged over an outside of the interior of the furnace neten drive.

This measure in turn has the advantage that in the interior of the Multi-purpose oven only the robust lifting element is added is wherever heat sensitive and steam sensitive Parts such as electric motors, corresponding cables, switches and Like. Are arranged outside the furnace chamber.  

In a further embodiment of the invention, the hub runs element via a fourth driven fixed roller with a gas-tight shaft passed through a wall of the furnace is connected to a drive shaft of the outside of the Furnace arranged drive is connected.

This measure has the advantage, as already related with the tension element mentioned that in a structurally simple manner the lifting element can be moved inside and also gas-tight connected to the drive located on the outside is.

In a further embodiment of the invention, that, from the first loose roll of the workpiece carrier towards seen the fourth driven fixed roller, the lifting element another fifth with a counterweight loosely rotates, which is arranged so that it their takes the lowest position when the first loose roll occupies its highest position or vice versa.

This measure has the advantage that the driven on both sides Roll that moves the lifting element back and forth, each of a loose roll about the same weights are carried, namely on the one hand the workpiece carrier including the batch and on the other hand that Balance weight, so that the drive only one Force has to be applied to the different weights to balance both sides.

In a further embodiment of the invention is a first Cooling chamber for cooling the workpieces using a cooling gas and a second cooling chamber in the form arranged next to it  a quench bath, especially in the form of an oil bath seen, and a foot extends over the quench bath rail along which the trolley can be moved horizontally is.

This measure has the advantage that a simple horizontal movement process from the heating chamber incoming batch by means of the transport device either in the first or in the second cooling chamber can be brought. Depending on the type of treatment, cooling can then take place in a gas atmosphere or cooling in a quench bath be performed. On the other hand, the measure has the advantage that the quenching bath, which is to be cooled with appropriately large Of course, batches are also appropriately large and is surrounded by a stable wall, at the same time a stable abutment for the horizontal guidance of the trolley can represent. The guide rails can then at for example directly on the top of the quench bath surrounding wall must be mounted, over which then the entire weight the transport device including the batch carried by it can be distributed.

In a further embodiment of the invention the antechamber at a first middle level and points a gas-tight lockable via a loading door opening on a second, lower level, The cooling chambers are located below the antechamber.

This measure has the advantage that the crane, which is in the Antechamber located above the cooling chambers only runs over this must be moved horizontally to the batch in  to bring the position from which they each into the chamber can be brought in or handed over. Since the antechamber with Shielding gas is filled, it is ensured that during the Transfer process from the heating chamber into the respective cooling Chamber no oxidation process can take place, which is Bringing the batch in place via the corresponding Cooling chamber can be accomplished very quickly.

In a further embodiment of the invention the heating chamber is on a third upper level and is on lower end with a lowerable via a first elevator or raised floor, which can be lowered so far that from the workpiece carrier plant arranged in the antechamber pieces can be placed on the floor or resting on it Workpieces are removable.

This measure has the advantage that the workpiece carrier itself does not have to enter the hot heating chamber at all. The Lowerable floor transports the hot batch after completion of the heat treatment process from the third higher upper Level above the first elevator by lowering the floor to such a level that a sideways approach of the Workpiece carrier, grab, lift and can laterally be transported away to them then feed to the low-level cooling chambers. The crane then only serves to keep the batch horizontal the middle level of the antechamber and if necessary in lower or lower the cooling chambers underneath to raise. The floor of the Heating chamber then ensures that the batch by the Workpiece carrier can be placed on the floor from  middle level of the antechamber to the higher level of Heating chamber can be brought. The leadership and the drives the crane can be arranged as far away from the heating chamber be that heat transfers from the heating chamber excluded are. For example, the first elevator can be a chain be designed elevator that the heavy batch together with the Bottom of the heating chamber moved in a vertical direction, d. H. raises or lowers.

In a further embodiment of the invention, the first comes Cooling chamber to lie under the heating chamber, being between lower end of the heating chamber and upper end of the first cooling chamber is an area of the antechamber, being in the first Cooling chamber a liftable or via a second elevator lowerable floor is provided, which can be raised as far as possible, that of the horizontally movable workpiece carrier in the prechamber Workpieces can be placed on the floor or rest on it Workpieces are removable.

This measure has the advantage that the lifting or lowerable floor in the first cooling chamber, in which a cooling the batch is carried out using a gaseous medium Transfer from the heating chamber accomplished quickly and easily can be. The crane then serves the batch, for example wise to take over from the lowered floor of the heating chamber and then on the raised floor of the first cooling chamber to put down again serves as an intermediate storage for the heat-treated workpieces. It is with this construction then sufficient, the trolley only in the area of Quench bath to be provided horizontally movable. The crane performs the horizontal movements of the batch inside the  Multi-purpose oven and immersion or lifting in the oil drain horror bath through. Between the middle level of the antechamber and the heating chamber located above the batch of the first elevator of the floor of the heating chamber. The vertical movement of the batch from the middle The level of the antechamber into the first cooling chamber is determined by means of of the second elevator.

In a further embodiment of the invention, the first is The cooling chamber can be separated gas-tight from the antechamber.

This measure has been particularly related to the previous one measure mentioned the advantage that a batch after it from the heating chamber via the crane to the lowerable floor was brought into the cooling chamber and sunk into it, the cooling chamber is closed and then a gas shaped cooling medium can be introduced. In the meantime can have another at the level above the antechamber Batch to be introduced from the outside, the oven then closed, flushed with protective gas and the Batch from the crane onto the lowered floor of the heating chamber be set. The floor of the heating chamber then follows above, the heating chamber is closed and it can be in the Heating chamber initiated a new heat treatment process be meanwhile arranged in the lower level closed first cooling chamber the cooling process takes place. To The cooling chamber can then be opened and the floor raised Batch can be removed from the multi-purpose furnace. At this A total of three transport devices necessary, namely the crane, the first and the second elevator, however, this additional construction effort is reduced Cycle times noticeable.  

Further advantages of the invention are the following description exercise.

It is understood that the above and the following standing features to be explained not only in each specified combination, but also in other combinations and can be used alone, without the scope of the to leave the present invention.

The invention is selected below based on a Embodiment in connection with the accompanying Drawings described and explained in more detail. Show it:

FIG. 1 is a highly schematic shows a vertical longitudinal section of a multi-purpose oven of the invention in a first operating condition;

Fig. 2 is a top view of the furnace of Fig. 1;

. Fig. 3 is a representation corresponding to Fig 1 in a second operating state of the multipurpose furnace;

FIG. 4 shows a representation of a third operating state of the multi-purpose furnace corresponding to the representation of FIG. 1;

Fig. 5 is a view of Fig. 1 corresponding representation in a fourth operating state, and

FIG. 6 shows a representation of the multi-purpose furnace corresponding to the representation of FIG. 1 in a fifth operating state.

A multi-purpose oven 10 shown in FIGS. 1 to 6 has a housing 12 which encloses an interior 13 .

The interior 13 is divided into a prechamber 14 , a first cooling chamber 16 , a second cooling chamber 18 , which contains an oil bath 20 , and a heating chamber 22 .

In the interior 13 , a transport device 24 is provided, which has a crane 26 , a first elevator 28 for a lowerable or elevatable floor 30 of the heating chamber 22 and a second elevator 32 for a raised or lowerable floor 34 of the first cooling chamber 16 .

In a wall 42 , in the representation of FIG. 1, the left side wall of the multi-purpose oven 10 , a loading opening 46 is provided at about half its height, which can be closed gas-tight by a loading door 44 .

The loading door 44 can, as shown in Fig. 1 by an arrow 47 , be raised so far that the loading opening 46 is released.

A charging machine 50 known per se is arranged immediately in front of the wall 42 , ie to the left of the wall 42 in the illustration in FIG. 1.

The charging machine 50 has a carriage 56 which can be displaced in a horizontal plane via rails 52 , 54 , as is indicated in FIG. 2 by a double arrow 55 . The carriage 56 rests on the rails 52 , 54 via a frame (not shown here), which in turn has two transverse rails 58 and 60 , which extend transversely between the rails 52 , 54 and thus run at right angles to them. The carriage 56 has, on its side facing the wall 42 of the multi-purpose furnace 10, five projecting forks 62 , the front end area of which serves to carry a batch 64 of workpieces. The transverse rails 58 , 60 or the lower edge of the forks 62 lie at such a height that when the loading door 44 is open, by moving the carriage 56, the forks 62 and the charge 64 received thereon can be pushed into the prechamber 14 , as shown in FIG. 1 is indicated by an arrow 65 .

The prechamber 14 is delimited in the area 46 immediately behind the loading door 44 by an upper wall 67 of the first cooling chamber 16 , which is provided with an opening 68 .

The upper wall 67 represents an upper end of the first cooling chamber 16 , which is arranged directly below the prechamber 14 in the previously mentioned area immediately behind the loading opening 46 .

A lower wall 69 of the heating chamber 22 represents an upward boundary of the antechamber 14 in the area behind the loading opening 46 .

A vertical wall 70 , which extends over the entire width of the housing 12 (see FIG. 2) and runs parallel to the wall 42 , separates the first cooling chamber 16 from the second cooling chamber 18 .

Another vertical wall 72 , which also extends over the entire width of the housing 12 , represents a rearward limitation of the second cooling chamber 18. In the illustration of FIG. 1, the rear of the multi-purpose oven therefore corresponds to the right side.

An oil bath 20 is received in the second cooling chamber 18 and is connected to a tank located outside the housing 12 by means not shown here. Circulation pumps are also provided, which circulate the oil bath 20 , as is known per se. Heating devices can also be provided in order to bring the oil bath 20 to a certain predetermined temperature, for example 95 ° or 150 ° C. Instead of oil, a salt bath can also be provided, it being possible for the liquid to be formed by a molten salt at approximately 300 ° C.

An upper wall 76 in the area above the oil bath 20 forms a closure of the housing 12 upwards, the wall 76 being approximately at the level of the wall 69 , which represents the lower closure of the heating chamber 22 .

The wall 76 lies approximately 5 m above a base 36 on which the housing 12 rests.

In the area above the first cooling chamber 16 or above the section of the first pre-chamber 14 located above it, there is a lifting hearth surrounded by a cylindrical wall 78 , the more detailed configuration of which is described in connection with FIG. 4.

A guide rail 80 , on which a trolley 82 rests, extends between the walls 70 , 72 , which form a left and a right boundary of the oil bath 20 in the illustration in FIG. 1.

The trolley 82 runs over wheels on its underside in the profiled guide rail 80 .

The trolley 82 is connected on its side facing a wall 116 at a point 84 to a chain 86 .

The wall 116 in the representation of FIG. 1 represents a rear vertical end wall of the housing 12 , viewed in the direction of view of the loading opening 46 towards the interior 13 , this represents the left end wall of the housing 12 .

The chain 86 connected to the trolley 12 , which is designed as an endless chain, runs around two rollers 88 and 90 lying on the same horizontal level.

The roller 88 comes to rest approximately at the upper end of the wall 70 , the roller 90 at the upper end of the wall 72 .

The roller 90 is a driven roller, which is pushed onto a driven shaft 92 , which extends through the wall 116 and is connected to a drive 120 arranged on the outside of the wall 116 (see FIG. 2). The shaft 92 is taken in a gas-tight sleeve, through the wall 116 .

If the shaft 92 together with the driven roller 90 firmly connected to it is rotated, for example, clockwise, the chain 86 , which is firmly connected to the trolley 82 via the point 84 , moves it to the right in the illustration in FIG. 1. If the shaft 92 is rotated counterclockwise, the chain 86 rotating over the roller 88 moves the trolley 82 to the left. The trolley 82 can be moved horizontally back and forth over the entire length of the guide rail 80 spanning the oil bath 20 , as is indicated by a double arrow 93 .

On the inside opposite point 84 , that is to say the side facing the viewer in FIG. 1, the trolley 82 is firmly connected to a vertically extending guide rail 96 .

The guide rail 96 is formed as a profiled steel beam which is welded to the trolley 82 .

The guide rail 96 is also still welded to the trolley 82 via diagonal struts, which are provided for reasons of stability, but are not shown in the drawing for reasons of clarity. At the upper end, the guide rail 96 is welded to a T-piece 98 , which is provided with a fixed roller 100 and 102 at its two outer ends. The distance between two imaginary vertical tangents at opposite circumferential points of the rollers 100 and 102 is such that this corresponds approximately to the diameter of a first loose roller 104 which is attached to a workpiece carrier 106 .

The workpiece carrier 106 runs by means of a guide wheel 107 in the U-profiled guide rail 96 , so that the workpiece carrier 106 can be moved in the vertical direction along the guide rail 96 .

The workpiece carrier 106 is provided with five horizontally projecting forks 108 , the contour and contact surface of which roughly corresponds to the forks 62 of the carriage 56 of the charging machine 50 , but are offset slightly laterally with respect to these, so that they can interlock, as will be described in more detail below.

In the illustration of Fig. 1, the "rearward" fork 108 is displayed, so the fork nearest the trolley 82 and the underlying wall facing 116th The four further forks 108 arranged congruently adjoin the viewer of FIG. 1, the "foremost" fork 108 , that is to say the closest to the viewer of FIG. 1, on its side facing the interior 13 with a corresponding one loose roller 104 is provided, which is associated with a workpiece carrier 106 mirror image workpiece carrier.

The workpiece carrier 106, which is the mirror image of the workpiece carrier, is then likewise received in a rail which is arranged in a mirror image of the profiled guide rail 96 and which is in turn connected to a mirror image of the trolley 82 . This then runs in a mirror image of the guide rail 80 arranged guide rail 80 'as indicated in Fig. 2. The mirror-image components are connected via cross beams 109 and 116 to form a rigid frame.

The first loose roller 104 hangs on a chain 122 that runs over the fixed rollers 100 , 102 of the T-piece 98 .

One end of the chain 122 is fixed in an eyelet 124 on the underside of the wall 76 . The eyelet 124 is arranged approximately in the illustration of FIG. 1 at the left end of the upper wall 76 , in the area in which the wall 78 of the lifting hearth furnace rises above it.

At the level of the fixed rollers 100 , 102 , in the illustration of FIG. 1, a fixed driven roller 110 is arranged in a right rear end region, over which the chain 122 runs.

The roller 110 is pushed onto a shaft 112 (see broken illustration of FIG. 2) which is guided through the wall 116 in a gas-tight bushing 114 , and the shaft 112 is with the drive shaft of a drive 118 arranged on the outside of the wall 116 connected.

The chain 122 , coming from the driven roller 110 , rotates a second loose roller 126 and is returned to an eyelet 130 , with which it is firmly connected. The eyelet 130 is fixedly attached to the underside of the top wall 76 .

The second loose roller 126 is provided with a counterweight 128 which corresponds approximately to the weight of the workpiece carrier 106 together with a batch 64 .

The axes of rotation of the fixed rollers 100 , 102 on the T-piece 98 , the first loose roller 104 on the workpiece carrier 106 , the fixed driven roller 110 and the second loose roller 126 all run parallel.

Furthermore, the rollers 100 , 102 , 104 , 110 and 126 are all in a vertical plane, so that the chain 122 also extends in a vertical plane.

As can be seen from the illustration of FIG. 1, the position of the first loose pulley 104 with respect to the second idling roller 126 such that, if as shown in Fig. 1, the first loose pulley 104 is in its highest position, the second loose Roll 126 occupies its lowest position.

If the drive 118 , which drives the roller 110 , is stationary and the trolley 82 is moved back and forth in the horizontal direction by means of the drive 120 , the chain 122 rotates the non-driven rollers 102 , 104 and 100 , ie the workpiece carrier 106 is kept at the same height level, but is shifted horizontally.

If the drive 120 is at a standstill and the drive 118 actuates the roller 110 in such a way that it is rotated counterclockwise in the illustration in FIG. 1, the first loose roller 104 and the workpiece carrier 106 are lowered, with the second loose roller 126 simultaneously together with the counterweight 128 is raised.

The further configurations of the multi-purpose furnace 10 are described in more detail below in connection with the mode of operation.

The multi-purpose oven described in Figures 1 to 6 operates as follows:
A batch 64 of workpieces to be treated is moved in front of the loading opening 46 by means of the charging machine 50 , as is shown in FIGS. 1 and 2. After opening the loading door 44 , the carriage 56 of the charging machine 50 is moved into the interior 13 until the batch comes to rest in the middle of the first area of the antechamber 14 , that is to say approximately in the middle above the first cooling chamber 16 . The crane 26 is then moved to the left in the illustration of FIG. 1 that the forks 108 of the workpiece carrier 106 reach under and receive the batch 64 .

The carriage 56 of the charging machine 50 is then pulled out of the multipurpose furnace 10 , the loading door 44 is closed and the interior 13 is subjected to a protective gas until all the air which has entered the interior 13 from the outside when the batch 64 is introduced, is rinsed out. For this purpose, protective inlet lines (not shown) are provided, as well as on oxygen to speaking sensors, as is known per se, to ensure that a complete protective gas atmosphere is present in the interior 13 .

The crane 26 then moves together with the batch 64 to the right that the floor 30 , which closes the heating chamber 22 on the lower side, can be lowered so far that the batch 64 can be lowered on the top of the lowered floor 30 by horizontal movement of the crane 26 can be lowered, as shown in Fig. 3.

For this purpose, the floor 30 is provided with two diametrically opposite, radially projecting projections 146 , 148 (see FIG. 2), each of which is connected to a chain 149 or 151 of the first elevator 28 .

The chains 149 and 151 run in vertical chain guides 150 and 152 before they are wound onto driven wheels 154 and 156, respectively. The drive wheels 154 and 156 are arranged on the top of the wall 69 on which the cylindrical housing 78 of the hearth furnace rests.

To lower the floor 30 into the position shown in FIG. 3, the chains 149 and 151 are unwound from the drive wheels 154 , 156 , wherein they are guided vertically by the chain guides 150 , 152 . As can be seen in particular from FIG. 2, the chain guides 150 , 152 are arranged outside the housing 78 of the lifting hearth base, that is to say they are located outdoors. Seals (not shown in detail here) are provided at the passage points of the chain guides 150 , 152 , so that no protective gas can escape.

After the crane 26 , as indicated in FIG. 3 by the arrow 132 , has been moved to the left and the batch 64 has been placed on the top of the lowered floor 30 , the crane 26 is moved to the right again and the floor 30 together with it recorded batch 64 raised, as indicated in Fig. 4 by the arrow 133 . At the bottom of the bottom 30 , a cover 138 is placed, which is provided with a seal 140 , which ensures a gas-tight seal between the pre-chamber 14 and the heating chamber 22 .

The inside of the cylindrical wall 78 of the hearth base and the side of the lowerable base 30 facing the heating chamber 22 are lined with fireclay 134 , as is known per se.

At the upper end, the heating chamber 22 is connected to a gas guide 142 , which ensures that appropriate treatment gases can be introduced into the heating chamber 22 . The gas duct 142 also serves to circulate the amount of gas received in the heating chamber 22 , so that a good heat exchange takes place between the heater 144 arranged in the heating chamber 22 and the charge 64 .

The batch 64 shown in FIG. 4 consists of large gearwheels with a diameter of approximately 1.5 m and has a weight of approximately 10 tons. The heat treatment takes place at 750 ° C for several hours.

If a nitrocarburization is to be carried out, a appropriate gas atmosphere set in the heating chamber, for example an ammonia-hydrogen hydrocarbon mixture.

After completion of the heat treatment, the process described in connection with FIG. 3 proceeds in reverse, ie the floor 30 is lowered with the hot batch 64 recorded thereon to such an extent that the crane 26 can remove the batch 64 from the floor 30 and then transports it over the Oil bath 20 . By actuating the drive 118 of the roller 110 , the latter is rotated, as a result of which the workpiece carrier 106 together with the hot batch 64 received thereon is very quickly lowered into the oil bath 20 , as is shown in FIG. 5. This process can also be carried out very quickly in the case of the large and heavy batch 64 , so that the batch 64 is completely immersed in the oil bath 20 within a few seconds, as a result of which no distortion can then occur due to unevenly quenched areas of the large gear wheels. The vapors rising in the quenching process can then rise into the heating chamber 22 and be discharged via the gas duct 142 from the multi-purpose furnace 10 , as is indicated in FIG. 5 by the flow arrows 162 .

Since, during the transfer of the hot batch 64 from the heating chamber 22 into the oil bath 20, the interior 13 is still sealed off from the outside world, there is no risk that the hot batch will oxidize before being immersed in the oil bath 20 .

FIG. 5 shows that the floor 30 has been raised in the meantime, but the cover 138 shown in FIG. 4 has not been applied, so that the vapors can flow through the heating chamber 22 .

After the batch 64 has been quenched in the oil bath 20 and cooled sufficiently, the workpiece carrier 106 is raised again and held over the oil bath 20 until the liquid has drained off. The loading door 44 is then opened and an empty carriage 56 of the charging machine 50 is pushed into the antechamber 14 to such an extent that the heat-treated, cooled, drained batch 64 can be placed on the forks 62 by the workpiece carrier 106 . The charging machine 50 is then pulled out of the multi-purpose oven 10 and fed to a further treatment station, in particular a washing station.

Then a new batch can be fed to the multi-purpose oven 10 .

Another operation of the multi-purpose oven 10 is shown in FIG . Starting from the situation in FIG. 4, the batch 64 was taken over by the crane 26 after the heat treatment had been carried out by lowering the floor 30 and the floor 30 was then moved up again.

At the same time, the floor 34 in the first cooling chamber 16 was raised by means of a second elevator 32 to such an extent that the batch 64 gripped by the crane 26 could be placed on it. The second elevator 32 is designed as a hydraulic elevator, but can also be ausgebil det as a chain hoist.

After the hot batch 64 was placed on the floor 34 by the crane 26 , it was lowered again and the first cooling chamber 16 was closed by means of the cover 160 . A gaseous cooling medium is introduced into the first, now closed cooling chamber 16 via a fan 158 and the hot charge 64 is cooled via the gaseous cooling medium, as is symbolically indicated in FIG. 6 by the flow arrows 164 .

During the cooling phase of the batch 64 in the closed first cooling chamber 16 , a further batch 64 'can be introduced into the furnace 10 , as was described in connection with FIGS. 1 to 3.

In Fig. 6, a situation is shown in which the batch 64 'is just placed by the crane 26 on the lowered floor 30 , as indicated by an arrow 166 . Here too, of course, the pre-chamber 14 was again flushed with protective gas. After depositing the batch 64 'on the floor 30 , the crane 26 is moved back to the right and the floor is raised, as indicated by the arrow 133 . A new heat treatment process can then already be started in the heating chamber 22 , while the cooling process of the batch 64 is still taking place in the cooling chamber 16 .

When this cooling process has ended, opening the lid 160 opens the first cooling chamber 16 , which is sealed off from the pre-chamber 14 , the floor 34 is raised so that the batch 64 , which has cooled in the meantime, can be gripped directly by the charging machine 50 and removed from the multipurpose oven can be. The loading door 44 is then closed again and the prechamber 14 or the first cooling chamber 16 is flushed out with protective gas.

Claims (13)

1. Multi-purpose furnace for the heat treatment of metallic workpieces ( 64 ), with a prechamber ( 14 ) which can be acted on with a protective gas, with a closable heating chamber ( 22 ) in which the metallic workpieces ( 64 ) are subjected to heat treatment, in particular a thermo-chemical treatment are subjected to at least one cooling chamber (16, 18) for cooling of the treated work pieces (64), and with a transport device (24) for transporting the workpieces (64) between the chambers, characterized in that the transport device (24) has a horizontally and vertically movable, arranged in the prechamber ( 14 ) crane ( 26 ). 2. Multi-purpose furnace according to claim 1, characterized in that the crane ( 26 ) has a horizontally movable trolley ( 82 ) which is fixed to a vertically extending guide ( 96 ) along which a vertically movable workpiece carrier ( 106 ) is introduced is. 3. Multi-purpose oven according to claim 2, characterized in that the trolley ( 82 ) via at least one in the interior ( 13 ) of the multi-purpose oven ( 10 ) arranged pulling element ( 86 ) can be moved horizontally back and forth, the at least one pulling element ( 86 ) itself is driven via a drive ( 120 ) arranged outside the interior ( 13 ) of the multi-purpose oven ( 10 ). 4. Multi-purpose oven according to claim 3, characterized in that the traction element is an endless element ( 86 ), in particular in the form of a chain, which runs around two fixed rollers ( 88 , 90 ), a driven roller ( 90 ) with one gas-tightly connected by a wall ( 116 ) of the multi-purpose furnace ( 10 ) guided shaft ( 92 ) which is connected to a drive shaft of the drive ( 120 ) arranged outside the wall ( 116 ). 5. Multi-purpose furnace according to one of claims 2 to 4, characterized in that the workpiece carrier ( 106 ) on a loose roller ( 104 ) attached to it on a lifting element, in particular in the form of a chain ( 122 ), hangs over two on both sides of the first loose Roller ( 104 ) located, at the upper end of the guide ( 96 ) arranged fixed rollers ( 100 , 102 ) runs. 6. Multi-purpose oven according to claim 5, characterized in that the lifting element ( 122 ) via an outside of the interior ( 13 ) of the multi-purpose oven ( 10 ) arranged drive ( 118 ) can be driven. 7. Multi-purpose oven according to claim 5 or 6, characterized in that the lifting element ( 122 ) runs over a fourth driven fixed roller ( 110 ) which with a gas-tight through a wall ( 116 ) of the multi-purpose oven ( 10 ) guided shaft ( 112 ) is connected, which is connected to a drive shaft of the drive ( 118 ) arranged outside the wall ( 116 ). 8. Multi-purpose furnace according to one of claims 5 to 7, characterized in that, seen from the first loose roller ( 104 ) of the workpiece carrier ( 106 ) in the direction of the fourth driven fixed roller ( 110 ), the lifting element ( 122 ) another, with a counterweight ( 128 ) provided fifth loose roller ( 126 ) which is arranged such that it assumes its lowest position when the first loose roller ( 104 ) is in its highest position, and vice versa. 9. Multi-purpose furnace according to one of claims 2 to 8, characterized in that a first cooling chamber ( 16 ) for cooling the workpieces ( 64 ) by means of a cooling gas and a second cooling chamber ( 18 ) arranged next to this in the form of a quenching bath ( 20 ), in particular an oil bath are provided, and that a guide rail ( 80 ) extends over the quench bath ( 20 ), along which the trolley ( 82 ) can be moved horizontally. 10. Multi-purpose furnace according to one of claims 1 to 9, characterized in that the prechamber ( 14 ) is at a first intermediate level, and has a loading opening ( 46 ) which can be closed gas-tight via a loading door ( 44 ), and that on one second lower level, below the prechamber ( 14 ) the at least one cooling chamber ( 16 , 18 ) is arranged. 11. Multi-purpose oven according to one of claims 1 to 10, characterized in that the heating chamber ( 22 ) is at a third upper level, and at the lower end with a via a first elevator ( 28 ) lowerable or raisable bottom ( 30 ) which can be lowered to such an extent that workpieces ( 64 ) can be placed on the floor ( 30 ) or workpieces ( 64 ) resting on them can be removed from the crane ( 26 ) arranged in the antechamber ( 14 ). 12. Multi-purpose oven according to one of claims 1 to 11, characterized in that the first cooling chamber ( 16 ) comes to rest under the heating chamber ( 22 ), with an area of the antechamber between the lower end of the heating chamber ( 22 ) and the upper end of the first cooling chamber ( 16 ) lies in the fact that in the first cooling chamber ( 16 ) a floor ( 34 ) which can be raised or lowered via a second lifting mechanism ( 32 ) is provided, which floor can be raised to such an extent that workpieces ( 64 ) on the floor by the crane ( 26 ) ( 34 ) can be removed or workpieces ( 64 ) resting thereon can be removed. 13. Multi-purpose furnace according to one of claims 1 to 12, characterized in that the first cooling chamber ( 16 ) can be separated in a gas-tight manner from the antechamber ( 14 ).