EP0922120A1

EP0922120A1 - Revolving furnace for the treatment of work pieces

Info

Publication number: EP0922120A1
Application number: EP97934473A
Authority: EP
Inventors: Franz Hillingrathner
Original assignee: Individual
Current assignee: Hillingrathner Franz
Priority date: 1996-08-30
Filing date: 1997-07-16
Publication date: 1999-06-16
Anticipated expiration: 2017-07-16
Also published as: EP0922120B1; ATE207546T1; WO1998008988A1; ES2163791T3; JP2000517045A; DE59705105D1; US5997290A

Abstract

A furnace body (10) houses a treatment rotor (30) which has charge locations (36) to take up a workpiece charge each and is supported so as to be driven in rotation around a central axis (A). The furnace body (10) communicates with side chambers (110, 110') equipped to receive a workpiece charge each from the treatment rotor (30) and to deliver it to the same, respectively. A lock rotor (60) likewise arranged in the furnace body (10) and adapted to be driven in rotation about the central axis (A) comprises at least two lock chambers (64) which are offset angularly relative to each other with respect to the central axis (A). The lock chambers (64) are opened alternately to the surroundings of the furnace body (10) and to a side chamber (110, 110') for reception and delivery of a workpiece charge each. Transfer apparatus (12) are provided for translating a respective workpiece charge between one each of the aforementioned chambers (64, 110, 110') and the treatment rotor, at least one those apparatus being designed for translating a workpiece charge each between the lock rotor (60) and the treatment rotor (30).

Description

Rotary cycle furnace for treating workpieces

The invention relates to a rotary cycle furnace for treating workpieces with

an oven housing which encloses an oven space in which an atmosphere deviating from the ambient air can be produced,

a treatment rotor which is arranged in the furnace housing such that it can be driven in rotation about a central axis and has a number of batch locations for accommodating one batch of workpieces each,

Secondary chambers which are connected to the furnace housing and are set up to take over a batch of workpieces from the treatment rotor or to deliver them to it,

- At least two lock chambers, which are arranged at an angle to one another with respect to the central axis and are open alternately to the surroundings of the furnace housing and to a secondary chamber for receiving and dispensing a batch of workpieces, and

- Transfer devices for transferring a batch of workpieces between each of the above-mentioned chambers and the treatment rotor.

Rotary cycle furnaces of this type are particularly suitable for heat treatments, for example for carburizing, nitriding, phosphating and / or hardening metallic workpieces. In a known generic rotary cycle furnace (DE 295 05 496 Ul), a feed lock arranged outside the furnace housing is accessible through an entrance gate and separated from a heating chamber by a first intermediate gate, which in turn is separated from an equalizing chamber by a second intermediate gate. The compensation chamber is attached radially on the outside of the furnace housing and separated from the furnace chamber by a third intermediate gate. Workpieces that are to be carburized and then hardened are arranged in batches on a pallet and transferred by transfer devices one after the other through the feed lock, the heating chamber and the compensation chamber into the furnace chamber ben, for which the above-mentioned gates have to be opened one after the other and closed again before the opening of the next gate in each case, so that a desired atmosphere which differs from the ambient air can be maintained in the chambers and in the furnace chamber. Two carburizing chambers are attached radially from the outside to the furnace housing, offset angularly against the compensation chamber and with respect to one another; these chambers are also separated from the furnace chamber by a normally closed gate. The same applies to a hardening furnace, which is also mounted radially on the outside of the furnace housing. An output lock connects to the hardening furnace and is also set up to quench the workpieces heated to the hardening temperature in the hardening furnace. This known arrangement takes up a relatively large amount of space for a given diameter of the furnace housing and requires considerable maintenance for the numerous gates required for the locks and further chambers.

The same also applies to other known rotary cycle furnaces of the type mentioned at the beginning (DE 40 05 956 Cl and EP 0 198 871 B1).

The invention is based on the object of designing a rotary cycle furnace for treating workpieces, in particular for hardening and tempering metallic workpieces, in a cost- and space-saving manner and to enable it to work in a time-saving manner.

The object is achieved based on a rotary cycle oven of the type mentioned in that

- The lock chambers are arranged in a lock rotor, which is also arranged in the furnace housing and can be driven in rotation about the central axis such that at least one lock chamber is periodically opened towards one of the secondary chambers, and

- At least one of the transfer devices is configured to transfer a batch of workpieces between the lock rotor and the treatment rotor. By placing the locks in a lock rotor coaxial with the treatment rotor, it is possible to control the opening and closing of the lock chambers in a particularly simple manner and to keep the space requirement of the entire arrangement small, even if considerably more than the usual two locks are provided.

The two rotors assigned to one another according to the invention are expediently driven separately and at different speeds. The treatment rotor requires a period of time corresponding to the required dwell time of the workpieces for a full revolution; the lock rotor needs for each full revolution e.g. just a twelfth of that time. If the angular velocity of both rotors is low, and if the workpiece batches either consist only of a relatively large workpiece or are inserted and removed on trays, pallets or the like, a continuous operation of both rotors is possible in principle. In general, however, it is preferable to operate the rotary cycle furnace according to the invention step by step. For this purpose, he is preferably trained in that

- The number of batch locations of the treatment rotor, which are arranged in a common level, is an integer multiple of the number of lock chambers of the lock rotor, and

- Both rotors can be driven step by step in such a way that the angular amount of each step of the lock rotor is an equally large multiple of each step of the treatment rotor.

In the event that workpieces are to be treated that are to be exposed to different influences in relatively long periods of time and have to dwell in different temperature zones for this purpose, the rotary cycle furnace according to the invention can be further developed in that the treatment rotor has at least two turntables, which axially offset from each other, insulated from each other and can be heated differently. In some cases, it is sufficient if at least one secondary chamber contains or can be connected to a device for cooling a batch of workpieces. The device for cooling can be a known type of quenching device, for example a nitrogen shower, an oil bath or the like. It is also possible to provide a further turntable for cooling the workpieces. However, the lock rotor is preferably designed to cool the workpieces. For this purpose, a coolant channel can be arranged on the furnace housing, which extends over an arc corresponding to at least one step of the lock rotor, is separated from adjacent secondary chambers and is connected in its arc length to at least one of the lock chambers.

The rotary cycle oven according to the invention only needs to be equipped with a single sealing arrangement which seals moving parts against stationary parts. This can be done in such a way that

- The furnace housing has an annular stationary sealing surface, and the lock rotor has a sealing surface rotating with it, and

- Between these two sealing surfaces, a sealing ring held against rotation is arranged, in which suitable passages of the same number and arrangement as the lock chambers are formed for moving one batch of workpiece through each.

It is also possible to have a stationary and a sealing surface formed on the furnace rotor or rotating with it interact directly with each other; However, a sealing ring arranged according to the invention has the advantage that it represents a relatively soft intermediate member that is subject to wear and, in contrast to its two contact partners, is relatively inexpensive to manufacture and can be replaced quickly. In addition, the sealing ring can compensate for radial runout and thermal expansion, especially if the sealing surfaces on the furnace housing and the lock rotor are convergingly conical and the sealing ring has a corresponding wedge profile and is biased in the axial direction.

The central axis of the rotary cycle oven according to the invention can in principle have any position in space; for example, it can be arranged horizontally if it is ensured that the workpieces to be treated individually or in larger batches, e.g. put on trays, adequately supported in the lock chambers and at the batch locations, e.g. pendulum bearings. However, an embodiment of the rotary cycle oven according to the invention has proven to be particularly advantageous in which

- the central axis is arranged vertically,

each of the batch locations has a plurality of lamellae which are arranged essentially upright, essentially radially to the central axis, but parallel to one another,

each lock chamber contains a lock space which is formed by correspondingly arranged slats,

- The transfer devices each have a radially displaceable, matching slat comb between the slats of the batch and lock spaces and

- The Laroellenankamm each transfer device between height positions that correspond to those of the rotors, can be raised and lowered.

The rotary cycle furnace according to the invention can be developed such that

- At least one secondary chamber is arranged opposite another secondary chamber in such a way that a lock chamber and a batch location are simultaneously accessible from these two secondary chambers, and

- These two secondary chambers each contain one of two transfer devices, which are controllable in such a way that one of them implements a workpiece collar from the lock rotor to the treatment rotor, and at the same time the other transfer device converts a workpiece batch from the treatment rotor to the lock rotor. With intermittent rotation of the two rotors, it is thus possible to keep their downtimes particularly short. Advantageous embodiments result from subclaims 8 and 9. With a suitable design of the transfer devices, a continuous rotary movement of the two rotors is also possible.

With the features of claims 10 to 12, the rotary cycle furnace according to the invention can be further developed in such a way that it enables a particularly precisely metered action on workpieces, in particular workpieces of low mass made of steel, to be hardened with little expenditure of energy and operating resources.

Exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. The drawings show:

1 shows a top view, partly as a horizontal section I-I in FIG. 3, of a first embodiment of a rotary cycle oven according to the invention;

Fig. 2 shows the section in the horizontal plane II-II in Figure 3;

Fig. 3 the vertical section III-III in FIG. 2;

Fig. 4 the vertical section IV-IV in FIG. 2;

Fig. 5 shows a greatly enlarged detail from FIG. 4;

Fig. 6 the vertical section VI-VI in FIG. 5; Fig. 7 shows a second embodiment of an inventive

Rotary cycle oven in horizontal section VII-VII in

Fig.9; Figure 8 shows the vertical section VIII-VIII in Figure 7; 9 shows the vertical section IX-IX in FIG. 7; 10 shows a plan view, partly as a horizontal section XX in FIG. 11, of a third embodiment of a rotary cycle oven according to the invention; 11 shows the vertical section XI-XI in FIG. 10; 12 shows the vertical section XII-XII in Fig.10; 13 shows the vertical section XIII-XIII in FIG. 10; and FIG. 14 a modification of FIG. 13. The rotary cycle furnace shown in Fig.l to 6 has a furnace housing 10 with a substantially cylindrical outer wall 12, a sub-floor 14 and an intermediate floor 16, which together enclose an evacuable furnace space 20, further with a cover 18 and with a lower housing part 22, which with the outer wall 12 and the underbody 14 consists of one piece.

On the intermediate floor 16, an upwardly projecting cylindrical collar 24 is formed, in which a hub 28 of a treatment rotor 30 is rotatably mounted about a vertical central axis A by means of radially inner bearings 26. The treatment rotor 30 has, as essential components, an upper turntable 32 and a lower turntable 34, both of which are circular and have numerous, in the example shown seventy-two, batch locations 36 and 38, respectively. Each of the batch locations 36 and 38 is formed by a plurality of horizontal, vertically arranged fins 40 which extend parallel to one another and essentially radially from the central axis A and are held together by a common annular base plate 42.

The treatment rotor 30 also includes three insulating plates 44, 46 and 48 arranged one below the other with the same axis as the central axis A, the upper batch locations 36 between the upper and the middle insulating plates 44 and 46, and the lower batch locations 38 between the middle and the lower insulating plate 46 or 48 are arranged such that a batch of workpieces W to be treated has space on each batch location. The insulating plates 44, 46 and 48 are preferably composite plates which are composed of two thin ceramic plates and three thick insulating plates made of hard graphite felt. All of the aforementioned plates 42 to 48 are rigidly but interchangeably connected to the hub 28 by means of axially parallel tie rods 49. The treatment rotor 30 constructed in this way can be driven in rotation about the central axis A by means of a motor 50. With the number of seventy-two batch locations 36 and 38 chosen as an example on each of the two rotary plates 32 and 34, each step extends over 5 °. In order that this step size is exactly maintained, the motor 50 is preferably a servo motor with a built-in, backlash-free reduction gear, for example a cyclo gear.

The batch locations 36 of the upper turntable 32 are arranged between two annular heating disks 52 concentric to the central axis A for high-temperature heating; In a corresponding manner, the batch positions 38 of the lower turntable 34 are arranged between two heating disks 54 for low-temperature heating. All of the heating disks 52 and 54 are jagged in a star shape according to the arrangement of the batch locations 36 and 38, preferably consist of molybdenum or graphite and are connected to an electrical power source via a central slip ring arrangement 56. Below the slip ring arrangement 56, the furnace housing 10 is closed with a cup-shaped closure 58.

Above the treatment rotor 30, separated from it by the intermediate floor 16, a lock rotor 60 is arranged in the furnace housing 10, which is also mounted on the collar 24 by means of outer bearings 62 and can be driven in rotation about the central axis A. The lock rotor 60 has several lock chambers 64, six in the example shown, which are offset from one another at angular intervals of 60 ° in a spoke-like part of the lock rotor and are only open radially to the outside in the embodiment shown in FIGS. On the outer wall 12 of the furnace housing 10, a first, second and third suction nozzle 66, 67 and 68 are arranged offset in the direction of rotation C, which can be connected to a suction pump for evacuating the lock chamber.

Horizontal slats 70 are arranged in an edgewise manner in each lock chamber 64, which extend at the same mutual distance as the slats 40 parallel to one another and essentially radially away from the central axis A and are connected to one another by a base plate 72. The bottom plates 72 of the sluice Senrotors 60, like the base plates 42 of the treatment rotor 30, have the task of preventing vibrations of the associated fins 70 or 40, in particular when the lock rotor 60 or treatment rotor 30 accelerates or brakes rapidly. The slats 70 in each of the lock chambers 64 form a lock place 74, on which a batch of workpieces W can be placed.

Each batch consists, for example, of five annular workpieces W arranged radially one behind the other, e.g. Ball bearing rings. In the event that the workpieces W to be treated are balls, the lamellae 40 and 70, as indicated in FIG. 5 on one of the lamellae 70, are each provided with a notch 75 on their upper side, so that each ball in notches of two adjacent ones Slats can be safely accommodated. However, it is also possible to arrange the workpiece batches on a pallet.

A stationary sealing surface 76 in the form of an inner cone is formed around the lock rotor 60 on the furnace housing 10 and, according to FIG. 5, has its smallest diameter at the bottom. The lock rotor 60 has a likewise conical outer sealing surface 78, which has its largest diameter at the bottom and is preferably ceramic-coated. Arranged between the sealing surfaces 76 and 78 is a correspondingly conical sealing ring 80, which in profile has the shape of a wedge tapering downwards, preferably essentially made of graphitized carbon or partially crystalline thermoplastic (PEEK), and one on the outer conical surface on the stationary one Has sealing surface 76 adjacent elastomer coating, while it bears directly on the outer sealing surface 78 of the lock rotor 60. The sealing ring 80 is prevented from rotating by means of a pin 82 fastened to it and parallel to the central axis A, which engages in a recess 84 in the cover 18, and is by means of the ceiling!). 18 supported springs 86 axially biased downwards. According to FIG. 2, six passages 88 are formed in the sealing ring 80, which pass at angular intervals of 60 °. are offset from one another and are in alignment with one of the lock chambers 64 whenever the lock rotor 60 is stationary.

The lock rotor 60 can be driven in rotation by means of two motors 90; with the number of six lock chambers 64 chosen as an example, each step extends over 60 °. The two motors 90, preferably electric servomotors, are arranged offset from one another by 180 ° and each have a backlash-free reduction gear with a pinion 91 which engages in a ring gear 92 arranged on the lock rotor 60 without backlash.

The outer wall 12 of the furnace housing 10 is thermally insulated, for example with hard graphite felt, and has six radial openings 94, each offset by 60 ° from one another, at the level of the lock rotor 60, each of which is aligned with one of the passages 88 of the sealing ring 80. In the area of one of the openings 94, a cladding 96 is attached to the outer wall 12 of the furnace housing 10 radially from the outside, which is open at the level of the lock rotor 60 through slots 98 to the outer surroundings of the furnace housing 10. A charger 100 for introducing and removing batches of workpieces into and out of the lock chambers 64 is arranged within the casing 96. The charger 100 has a lamellar comb 102 which fits between the lamellae 70 of the sluice rotor 60, each forming one of the lock positions 74. The lamella comb 102 can be slightly raised and lowered along a vertical pivot axis B and about this pivot axis B from a radial position with respect to the central axis A in both directions, through one of the slots 98 of the panel 96 through 90 ° in each case pivotable on the outside and is arranged on a carriage 104 which is radially displaceable towards and away from the central axis A. A lifting drive 105 is provided for lifting and lowering, a swivel drive 106 for pivoting, and a sliding drive 108 for radial displacement; these three drives can also each have an electric servo motor. The five remaining openings 94 in the outer wall 12 of the furnace housing 10 each open into an auxiliary chamber 110, which is hermetically sealed to the outside and contains a transfer device 112 in the exemplary embodiment of the rotary cycle furnace shown in FIGS. Each of the total of five transfer devices 112 has a lamellar comb 114 which corresponds to the lamellar comb 102, but in contrast to it is always arranged radially, but can be adjusted along a vertical column 116 between height positions that those of the two turntables 32 and 34 and the lock chambers 64 correspond. The column 116 is fastened on a slide 118 which can be adjusted radially to and away from the central axis of rotation A by means of a motor 120. Motor 120 drives a nut that produces a reciprocating motion of a hollow spindle 122 attached to carriage 118. A further motor 124 is provided for lifting movements, which is flanged to the motor 120 coaxially and drives a shaft 126. The shaft 126 extends through the hollow spindle 122 and in turn drives a vertical spindle 128 which is in threaded engagement with the lamellar comb 114 in order to raise and lower it.

At least one of the secondary chambers 110 can contain a device 130 for cooling or quenching the previously heated workpieces W; As indicated in the right part of FIG. 4, this device 130 can be designed such that a cooling gas, for example nitrogen, can be passed through the relevant secondary chamber 110. Alternatively, an oil bath can be provided as a quenching device in one of the secondary chambers 110.

In the first secondary chamber 110, which follows the cladding 96 in the direction of arrow C in FIG. 2, in addition to the opening 94 connecting it to the lock rotor 60, an additional opening 132 also formed in the outer wall 12, which connects this secondary chamber with the upper turntable 32 connects. An opening 134 opens into the last secondary chamber 110 connects them to the lower turntable 34. All openings 94, 132 and 134 in the outer wall 12 of the furnace housing 10 and the passages 88 of the sealing ring 80 are dimensioned such that one of the lamellar combs 102 or 114 radially therethrough between the lamellas 40 of the treatment rotor 30 or between the lamellas 70 of the Lock rotor 60 can be inserted.

The rotary cycle furnace shown in Fig.l to 6 works as follows:

The lamella comb 102 of the charger 100 is pivoted out of the casing 96, for example clockwise, as shown in FIG. 2, and is loaded with a batch of workpieces W. This can be done by placing the workpieces W directly on the lamella comb 102 or by placing them on a pallet or by placing them on a tray which is then taken over by the lamella comb 102. Then the lamellar comb 102 is pivoted together with the workpiece batch into its radial normal position and then, with the lock rotor 60 at a standstill, moved radially inward into the lock chamber 64 which is just radially aligned with the lamellar comb 102. In the meantime, the lamella comb 102 assumes a height position which lies somewhat above the upper edges of the lamella 70. As soon as the lamella comb 102 has reached its radially inner position, it is lowered to such an extent that the batch of workpieces is placed on the lamellae 70, and thus on the lock place 74 of the lock chamber 64 in question.

Subsequently, the lamellar comb 102 is withdrawn radially outward, and the lock rotor 60 is rotated by one step, in the example shown by 60 °, for example counterclockwise, as indicated in FIG. 2 by the arrow C. In the meantime, the lock chamber 64 occupied with the first workpiece batch moves past the first suction port 66; in the evacuated state, this lock chamber 64 thus reaches the position in which it is aligned with the first secondary chamber 110. The transfer device 112 arranged there fetches the workpiece batch radially out of the said lock chamber 64, moves it down into the plane of the upper turntable 32, pushes the workpiece batch in the radial direction into this turntable and places it on one of its batch locations 36 with a slight further downward movement. The treatment rotor 30 is then rotated by one step, that is to say by 5 °.

This sequence of processes is repeated with successive lock chambers 64 of the lock rotor 60 and with successive batch locations 36 of the upper turntable 32 until it is completely occupied, in the example shown with a total of seventy-two workpiece batches.

As soon as the batch of workpieces placed on the upper turntable 32 has participated in a full revolution of the treatment rotor 30 and has been heated by the two upper heating disks 52 to a certain temperature, for example sufficient for hardening, that which is arranged in the first secondary chamber 110 Transfer device 112 is used to lift this workpiece batch from its batch location 36 on the upper turntable 32 and to deposit it in the lock chamber 64 which has just become free, so that during the next step of the lock rotor 60 this heated workpiece batch comes into a position opposite the second secondary chamber 110, which in the direction of arrow C in Figure 2 follows the panel 96. The transfer device 112 arranged there removes the workpiece batch from the lock rotor 60 so that it is exposed to a nitrogen shower or immersed in an oil bath, so that the workpieces W of the batch under consideration are quenched.

The batch of workpieces under consideration is then deposited again on the same empty lock slot 74 by the same transfer device 112 arranged in the second secondary chamber 110, and the lock rotor 60 is rotated by a further step. The workpiece batch under consideration thereby reaches the area radially within the third secondary chamber 110, from there it is arranged transfer device 112 taken over, further cooled in the third secondary chamber 110 and then returned to its previous lock place 74. After a further step of the lock rotor 60, the workpiece batch in question is further cooled in the fourth secondary chamber 110, if necessary, and then returned to its previous lock location 74.

In the next step of the lock rotor 60, the now sufficiently cooled workpiece batch arrives at the fifth secondary chamber 110. On the way there, the lock chamber 64, which contains this workpiece batch, moves past the second suction port 67 and is thereby removed from the coolant contained therein, e.g. Nitrogen, or free from oil vapors. The batch of material under consideration is then removed from its lock chamber 64 by means of the transfer device 112 arranged in the fifth secondary chamber 110 and placed on a batch location 38 of the lower turntable 34. This sequence of operations is repeated until the lower turntable 34 is also completely filled with workpiece batches.

On the lower turntable 34, the workpiece batch considered and each subsequent batch takes part in a full revolution of the treatment rotor 30 in order to be heated to a tempering temperature. Each individual batch of workpieces is then picked up by the transfer device 112 in the fifth secondary chamber 110 and deposited on the lock space 74 which has just become available vertically above the lower batch space 38 which it has previously occupied. Finally, the batch of workpieces under consideration and each subsequent batch takes part in a last step of the lock rotor 60, as a result of which, past the third suction port 68, it comes back into the working area of the charger 100, is picked up by the latter and is brought out of the casing 96 to the outside.

The rotary cycle furnace according to FIGS. 7 to 9 differs from the exemplary embodiment shown in FIGS. 1 to 6 in that the treatment rotor 30 and the lock rotor 60 radially on the outside are stored; their bearings 26 and 62 are arranged on the outer wall 12 of the furnace housing 10. The space radially within the two rotors 30 and 60 is used to accommodate the casing 96 with the charger 100 and the five secondary chambers 110 with one of the transfer devices 112 each. The charger 100 and the conversion devices 112 are arranged according to FIGS. 7 to 9 in reverse to FIGS. 1 to 6; the lamella combs 102 and 114 are thus directed radially outward with the free ends of their lamellae. The sealing ring 80 seals against a cylindrical inner wall 136 of the furnace housing 10, and the openings 94, 132 and 134 are arranged in this. The lock chambers 64 are open radially inwards according to FIGS. 7 to 9. Accordingly, the lock spaces 74 and the batch spaces 36 and 38 are loaded radially from the inside to the outside with one batch of workpieces each and emptied in the reverse direction.

The cladding 96 forms a feed channel 138 which extends radially outward above the cover 18 of the furnace housing 10. In the feed channel 138, a rotating body 140 is rotatably arranged by means of a motor 142, in each case by 180 ° about a vertical axis of rotation D. The rotating body 140 has two diametrically opposite lamella arrangements 144, into which the lamella comb 102 of the charging device 100 can be inserted radially. The charger 100 interacts with the rotating body 140 for depositing and removing workpiece batches in the same way as with the sluice rotor 60. The mode of operation of the rotary cycle furnace shown in FIGS. 7 to 9 is basically the same as that with reference to FIGS. 1 to 6 has been described.

In the rotary cycle furnace shown in FIGS. 10 to 14, the furnace housing 10 has, in addition to the upper intermediate floor 16, a lower intermediate floor 17. The upper rotary plate 32 of the treatment rotor 30 is arranged between the two intermediate floors 16 and 17 in an evacuable part of the furnace space, and the lower turntable 34 is between the underbody 14 and the lower intermediate floor 17 in a normally non-evacuated ized but arranged with atmospheric air or with an inert gas such as nitrogen-filled part of the furnace chamber 20. The two turntables 32 and 34 are sealed against one another, heat-insulated from one another and can be heated independently of one another. According to FIG. 12, each of the two motors 50 drives two pinions 51, each of which is in constant engagement with a toothed ring on the upper or lower turntable 32 or 34.

Instead of being arranged in one of two parts of the furnace chamber 20 separated from one another by the lower intermediate floor 17, as shown, the two rotary plates 32 and 34 can each be a double-disc arrangement which is sealed against the furnace housing 10 and each itself a delimited part of the furnace chamber 20 forms. In this case, it suffices if the treatment rotor 30, as in the exemplary embodiments shown in FIGS. 1 to 9, has only one common ring gear for both turntables 32 and 34 and the motors 50 accordingly drive only one pinion 51 each.

The lock rotor 60 also has six lock chambers 64 in the exemplary embodiment shown in FIGS. 10 to 14, which are arranged offset from one another at angular intervals of 60 °, but are open radially outwards and radially inwards, in contrast to the previous exemplary embodiments. Around the lock rotor 60, a stationary, radially outer sealing surface 76 in the form of an inner cone is formed on the furnace housing 10 and has its smallest diameter at the bottom. Concentrically to this, a likewise stationary, radially inner sealing surface 76 'in the form of an outer cone is formed on the furnace housing 10 and has its largest diameter at the bottom. The rotorchleusen- rotor 60 has a likewise conical radially outer sealing surface 78, which has its largest diameter at the bottom, and a conical radially inner sealing surface 78 ', which has its smallest diameter at the bottom. A correspondingly conical outer sealing ring 80 is arranged between the sealing surfaces 76 and 78 and has the shape of a wedge tapering downwards in profile. Between the sealing surfaces 76 'and 78' is a sealing ring 80 corresponding, but smaller in diameter inner sealing ring 80 'arranged. Each of the sealing rings 80 and 80 'is prevented from rotating by means of a key 160 or 160' which is fastened to it and which is parallel to the central axis A and which engages in a corresponding recess 84 or 84 'of the cover 18 and is secured in the cover 18 guided and pressurized with pressure gas, for example nitrogen, piston 162 or 162 'axially biased downward.

For loading and emptying and for evacuating the lock chambers 64, four outer radial passages 88 are formed in the outer sealing ring 80, which are arranged at angular intervals of 60 ° to one another in the upper half of the outer sealing ring 80 according to FIG. 10, and whenever the Lock rotor 60 stands still, with each of the lock chambers 64 aligned. The inner sealing ring 80 'has two diametrically opposed inner radial passages 88', each of which is aligned with one of the outer passages 88. In addition, the sealing rings 80 and 80 'in their lower area according to FIG. 10 have a larger number of closely spaced slots 146 and 146' for introducing and discharging a coolant into and out of the lock chambers 64.

The outer wall 12 of the furnace housing 10 has four outer radial openings 94, each offset by 60 ° from one another, at the level of the lock rotor 60, each of which is aligned with one of the passages 88 of the outer sealing ring 80. The inner wall 136 of the furnace housing 10 has two inner radial openings 94 'at the level of the lock rotor 60, which are arranged diametrically opposite one another and are each aligned with one of the passages 88' of the inner sealing ring 80 '. Around two of the outer openings 94, a cladding 96 is attached to the outer wall 12 of the furnace housing 10 radially from the outside, which is open at the level of the lock rotor 60 through a slot 98 to the outer environment of the furnace housing 10. A charger 100 for introducing or removing batches of workpieces into and out of the lock chambers 64 is arranged inside the cladding 96. The two other, diametrically opposite, openings 94 in the outer wall 12 of the furnace housing 10 each open into an outer secondary chamber 110, which is hermetically sealed from the outside and contains an outer transfer device 112. The inner wall 136 of the furnace housing 10 encloses two inner secondary chambers 110 ', which are separated from one another by a vertical partition wall 148 and each contain one of two conversion devices 112' arranged diametrically opposite one another.

Each of the total of four transfer devices 112 and 112 'has a lamellar comb 114 or 114', which corresponds to the lamellar combs 102 of the charging devices 100, but in contrast to these are always arranged radially, but instead along a vertical column 116 or 116 'between height positions is adjustable, which correspond to those of the upper or lower turntable 32 or 34 and the lock chambers 64. The columns 116 and 116 'are each attached to a carriage 118 and 118', which can be adjusted radially to and away from the central axis of rotation A by means of a motor 120 or 120 '. Each of the motors 120 and 120 'drives a nut which produces a reciprocating motion of a hollow spindle 122 or 122' attached to the associated carriage 118 or 118 '. A further motor 124 or 124 'is provided for lifting movements, which is flanged to the motor 120 or 120' coaxially and drives a shaft 126 or 126 '. The shaft 126 or 126 'extends through the associated hollow spindle 122 or 122' and in turn drives a vertical spindle 128 or 128 'which is in threaded engagement with the associated lamellar comb 114 or 114' in order to lift it and lower.

In addition to the upper outer opening 94 connecting them with the lock rotor 60, an outer central opening 132, also formed in the outer wall 12, opens into the outer secondary chamber 110 on the left according to FIGS. 10 and 11, through which the outer rotary chamber 110 leads to the upper turntable 32 is accessible. A central inner opening formed in the inner wall 136 is aligned with this central outer opening 132 132 ', through which the upper turntable 32 is accessible from the inner secondary chamber 110'. A lower outer opening 134, through which the lower turntable 34 is accessible, opens into the outer secondary chamber 110 arranged on the right according to FIGS. 10 and 11. Aligned with this lower outer opening 134 is a lower inner opening 134 'formed in the inner wall 136 through which the lower turntable 34 is accessible from the inner secondary chamber 110'. All openings 94, 94 ', 132, 132', 134 and 134 'of the furnace housing 10 and the passages 88 and 88' of the sealing rings 80 and 80 'are dimensioned such that one of the lamellar combs 102 and 114 or 114 'can be inserted between the fins 40 of the treatment rotor 30 or between the fins 70 of the lock rotor 60.

The outer secondary chamber 110 arranged on the left in accordance with FIGS. 10 and 11 and the associated inner secondary chamber 110 'are constantly connected to the upper turntable 32 and, like the associated part of the furnace chamber 20, are constantly evacuated during operation. The right outer secondary chamber 110 and the associated inner secondary chamber 110 ', on the other hand, are constantly connected to the lower turntable 34 and the part of the furnace space 20 surrounding it and therefore contain the atmosphere prevailing there, e.g. hot nitrogen, with which the workpieces are brought to the tempering temperature.

The transfer device 112 in the left-hand outer chamber 110 according to FIGS. 10 and 11 is equipped with a heating plate 150 which is arranged at a distance above the lamella comb 114 and which heats workpieces lying thereon from above, e.g. electro-inductive or by heat radiation.

In the third exemplary embodiment of a rotary cycle furnace shown in FIGS. 10 to 14, in contrast to the first and second exemplary embodiments, a device with coolant supply ducts 152 and 152 ′ is provided for quenching the workpieces W, which runs along the outer wall 12 and inner wall 136 of the furnace housing 10 extend over a very wide angular range of approximately 160 ° in the circumferential direction, so that they are constantly connected to two, sometimes even three, successive lock chambers 64 and supply them with coolant, for example cold nitrogen. The coolant is discharged through coolant discharge channels 154 and 154 ′ after it has flowed through the lock chambers 64 connected to them. The slots 146 and 146 'emanate from or open into these channels, extend through the furnace wall 12 and 136 and the sealing ring 80 and 80' and enable the simultaneous flow through all lock chambers 64 which cover the area between the coolant supply channels 152, 152 'and the coolant discharge channels 154, 154' arranged between them.

The lock place 74 of each lock chamber 64 is enclosed according to FIGS. 13 and 14 by an interchangeable sleeve 156, which extends radially to the central axis A, is open radially on the inside and outside, consists of perforated sheet metal and carries the associated slats 70. The surroundings of the sleeve 156 are each connected to the coolant supply channels 152, 152 ', and the interior of the sleeve 156 to the coolant discharge channels 154, 154', as long as the lock chamber 64 in question passes through the described angular range of these channels.

The rotary cycle furnace shown in Fig. 10 to 14 works as follows:

The lamella comb 102 of the charger 100 arranged on the left in accordance with FIGS. 10 and 12 is pivoted out of the associated cladding 96 and loaded with a batch of workpieces W; then the lamella comb 102 is pivoted into its normal radial position and is moved radially inward into the lock chamber 64 which is just radially aligned with this lamella comb 102. The batch of workpieces is then deposited on the lock place 74 of the lock chamber 64 in question and the lamella comb 102 mentioned is withdrawn radially outward. The lock rotor 60 is then rotated by one step, in the example shown by 60 °, in the direction of arrow C in FIG. 10. The lock chamber 64 occupied with the first workpiece batch moves past the suction nozzle 66, which is arranged on the outer wall 12 of the furnace housing 10 and is connected to a suction pump. The above-mentioned lock chamber 64 thus reaches the position in the evacuated state in which it has a connection with the left outer secondary chamber 110 according to FIGS. 10 and 11 and at the same time with the left inner secondary chamber 110 '. The transfer device 112 'arranged in the latter pulls the workpiece batch radially out of the said lock chamber 64, moves it downward into the plane of the upper turntable 32, pushes the workpiece batch radially outward into this turntable and, with a slight further downward movement, sets it on one of its Batch places 36 from. The treatment rotor 30 is then rotated by one step, that is to say by 5 °.

As soon as the batch of workpieces placed on the upper turntable 32 has participated in a full revolution of the treatment rotor 30 and has been heated to a certain temperature, which is necessary, for example, for hardening, the transfer device 112 is arranged on the left in accordance with FIGS. 10 and 11 outer secondary chamber 110 is used to lift this workpiece batch from its batch location 36 on the upper turntable 32, to keep it at the hardening temperature by means of the heating plate 150 and to deposit it in the lock chamber 64 above it on its lock location 74. This lock chamber 64 has become free in that the simultaneously operating transfer device 112 'in the left inner secondary chamber 110' has brought an untreated batch of workpieces from this lock chamber to the batch location 36 which has just become free. The heated workpiece batch arrives at the next step of the lock rotor 60 in the area of action of the coolant supply channels 152, 152 ', so that the workpieces W of this batch are quenched, and because of the long action of the coolant which lasts for almost three steps of the lock rotor 60, they act on a relative low temperature, for example to 5 ° C, can be cooled.

In the fourth step of the lock rotor 60, the workpiece batch, which has now cooled sufficiently, reaches a position between the right outer secondary chamber 110 and the right inner secondary chamber 110 'according to FIGS. 10 and 11. There, the material batch under consideration is taken out of its lock chamber 64 by the inner transfer device 112 'arranged in the right inner secondary chamber 110' and placed on a batch location 38 of the lower turntable 34. This sequence of operations is repeated until the lower turntable 34 is completely occupied, ie in the example shown with seventy-two batches of workpieces.

As soon as the workpiece batch placed on the lower turntable 34 has again participated in a full revolution of the treatment rotor 30 and has been heated to a certain temperature, for example necessary for starting, this workpiece batch is converted by the transfer device 112 in the manner shown in FIGS. 10 and 11 outer secondary chamber 110 arranged on the right is picked up from its batch location 38 at the lower turntable 34 and placed on the lock space 74 just above it which has just become vacant.

This lock chamber 64 with its lock location 74 has become free in that the simultaneously operating transfer device 112 'in the right inner secondary chamber 110' has brought a quenched workpiece batch from this lock location to the batch location 38 which has just become free.

Finally, in a sixth step of the senrotors 60 part, whereby it, past the suction port 68, reaches the working area of the charger 100 arranged on the right in FIG. 1, is picked up by the latter and is pivoted outward from the associated cladding 96.

This completes the filling of the furnace with batches of workpieces - in the example shown this takes approximately 22 minutes - and it starts to leave the furnace in the finished heat-treated state at intervals of only 9 seconds, while an untreated batch of workpiece continues at the same intervals is fed to the furnace. The workpiece batches remain on the two rotating plates of the treatment rotor in the example shown, each 10.8 minutes. Before the furnace is retrofitted and / or repaired, the process of emptying the workpiece batches, which is the opposite of filling it up, takes place; in the example shown, it would also take about 22 minutes.

The rotary cycle furnace according to the invention enables an almost continuous, fully automatic heat treatment sequence that can be fully integrated and linked into the production line, as well as a product-related increase in quality and quantity.

Claims

claims

1. rotary cycle furnace for treating workpieces (W), with

- an oven housing (10) which encloses an oven chamber (20) in which an atmosphere deviating from the ambient air can be produced,

- A treatment rotor (30) which is arranged in the furnace housing (10) so as to be rotatably drivable about a central axis (A) and has a number of batch locations (36) for receiving one batch of workpieces each,

Secondary chambers (110) which are connected to the furnace housing (10) and are set up to take over a batch of workpieces from the treatment rotor (30) or to deliver them to it,

- At least two lock chambers (64), which are arranged at an angle to one another with respect to the central axis (A) and are open for receiving and dispensing a batch of workpieces alternately to the surroundings of the furnace housing (10) and to a secondary chamber (110), and

- Transfer devices (112) for transferring a batch of workpieces between each of said chambers (64, 110) and the treatment rotor (30), characterized in that

- The lock chambers (64) are arranged in a lock rotor (60) which is also arranged in the furnace housing (10) and can be driven in rotation about the central axis (A) in such a way that at least one lock chamber (64) periodically to one of the secondary chambers (110 ) is open, and

- At least one of the transfer devices (112) is designed to transfer a batch of workpieces between the lock rotor (60) and the treatment rotor (30).

2. rotary cycle furnace according to claim 1, characterized in that

- The number of batch locations (36) of the treatment rotor (30), which are arranged in a common plane, is an integer multiple of the number of lock chambers (64) of the lock rotor (60), and

- Both rotors (30, 60) can be rotated step by step such that the angular amount of each step of the lock rotor (60) is an equally large multiple of each step of the treatment rotor (30).

3. Rotary cycle furnace according to claim 1 or 2, characterized in that the treatment rotor (30) has at least two turntables (32, 34) which are axially offset from one another, thermally insulated from one another and can be heated differently.

4. Rotary cycle furnace according to one of claims 1 to 3, characterized in that on the furnace housing (10) at least one coolant channel (152, 154; 152 '154') is arranged, which over an arc corresponding to at least one step of the lock rotor (60) extends, is separated from adjacent secondary chambers (110; 110 ') and is connected to at least one of the lock chambers (64) over its entire arc length.

5. rotary cycle furnace according to one of claims 1 to 4, characterized in that

- The furnace housing (10) has at least one annular stationary sealing surface (76; 76 '), and the lock rotor (60) has a sealing surface (78; 78') rotating with it, and

- Arranged between these two sealing surfaces (76, 78; 76 ', 78') is a sealing ring (80; 80 ') which is held against rotation and in which passages (88) suitable for moving through a batch of workpieces in the same number and arrangement as the lock chambers (64) are formed.

6. rotary cycle furnace according to one of claims l to 5, characterized in that

- the central axis (A) is arranged vertically,

each of the batch places (36) has a plurality of fins (40) which are arranged essentially upright, essentially radially to the central axis (A), but parallel to one another,

each lock chamber (64) contains a lock place (74) which is formed by correspondingly arranged lamellae (70),

- The transfer devices (112) each have a radially displaceable, between the lamellae (40, 70) of the batch and lock spaces (36, 74) matching lamella comb (114) and

- The lamella comb (114) of each transfer device (112) between height positions that correspond to those of the rotors (30, 60), can be raised and lowered.

7. rotary cycle furnace according to one of claims 1 to 6, characterized in that

- At least one secondary chamber (110) of a further secondary chamber (110 ') is arranged opposite one another such that one and the same lock chamber (64) and one and the same batch location (36) are simultaneously accessible from these two secondary chambers (110, 110') are and

- These two secondary chambers (110, 110 ') each contain one of two transfer devices (112, 112') which can be controlled in such a way that one of them carries a batch of workpieces from the sluice rotor (60) to the treatment rotor (30), and at the same time the other transfer device implements a batch of workpieces from the treatment rotor (30) to the lock rotor (60).

8. rotary cycle oven according to claim 7, characterized in that

- The two rotors (30, 60) are annular and

- At least one inner secondary chamber (110 ') is arranged radially within the two rotors (30, 60).

9. rotary cycle oven according to claim 8 in conjunction with claim 3, characterized in that

the inner secondary chamber (110 ') contains two inner transfer devices (112') which are diametrically opposed to one another,

- The two inner conversion devices (112 ') each have an external conversion device (112) arranged radially opposite each in an outer secondary chamber (110),

- One of the inner transfer devices (112 ') and the radially opposite outer transfer device (112) for transferring workpiece batches between the lock rotor (60) and one of the turntables (32) is provided, and

- The other inner transfer device (112 ') and the radially opposite outer transfer device (112) for transferring batches of work between the lock rotor (60) and the other turntable (34) is provided.

10. rotary kiln according to claim 9, characterized in that the two turntables (32, 34) are sealed against each other, so that a different atmosphere can be maintained at the batch locations (36) of the first turntable (32) than at the batch locations (38) of the second turntable (34).

11. Rotary cycle furnace according to claim 9 or 10, characterized in that at least the auxiliary chamber (110) provided for moving the workpieces (W) from the first rotary plate (32) to the lock rotor (60) has a heater with which it can be prevented The temperature of the workpieces (W) drops significantly during the transfer.

12. rotary cycle oven according to claim 11, characterized in that the transfer device (112) in the heatable secondary chamber (110) has a heating plate (150).