EP0533615B1 - Installation for the thermal treatment of successive charges - Google Patents

Abstract

The charging trolley (25) brings the charge and deposits it on the plug (10) of the oven (1). <??>The introduction of the charge into the oven (1) and its closure are performed by the action of the lift (12) which comes down again after the treatment to an intermediate position, from which the oven (1) can be moved horizontally, the lower belt (4) pushing the base grid of the charge onto the lid (17) and the tray (22) of the lift (18) placed in upper position. The lid (17) ensures that the oven opening is sealed against the gases for protecting the charge. <??>This lift makes it possible to introduce the charge into the quenching tank and then to return it into a draining position and to deposit it on the discharging trolley (38) travelling on the line (36, 37). <IMAGE>

Description

Processing installations comprising one or more ovens, as well as one or more tanks and means for transferring a load successively from a loading station into the oven, then into the tank and then extracting this load from the tank and l to bring to an exit station, already exist. Mention will be made in particular of European patent application No. 0 296 102 which was published on December 21, 1988.

Swiss patent CH-478,918 also describes such an installation. In the latter, the bell is suspended inside the oven by suspension means which are capable of rotating it around its axis when the elevator is in the upper position, so that the load can be placed on supports projecting from the inner wall of the bell.

This known installation makes it possible to transfer the load from the elevator to the oven, then from the latter to the quenching tank, but the attachment of the load to the bell is a delicate operation and on the other hand when the oven is moved from the change position to the transfer position in the tank, the base of the oven is open and therefore the load is subject to the risk of oxidation. Another drawback of this known installation is that the bell suspension means prevent the placing of a gas circulation turbine at the most favorable location, ie at the top of the furnace, in the axis of the bell.

The object of the present invention is to design an installation of the type indicated simpler than the already known installations, capable of being controlled manually, while guaranteeing a circulation of the charge between the various elements of the installation which eliminates the risks for the treated parts, in particular the risks of contact with air, and consequently of oxidation.

To this end, the subject of the present invention is an installation for the heat treatment of successive loads, comprising an oven with vertical arrangement, open downwards and situated in a higher position, a container provided with a lift and placed in a position lower, a horizontal access path installed at the height of the base of the tank, provided with loading means, and a charging lift placed next to the tank so as to raise a load placed by the loading means on the elevator to introduce it into the oven, the latter being movable horizontally between a position above the charging elevator and a position above the tray, characterized by a sliding plane placed at the height of the base of the oven and allowing the shifting of a load supported by the charging elevator at the height of said plane, by movement of the oven.

• la fig. 1 est une vue en élévation schématique vue dans la direction des voies parallèles de chargement et de déchargement,
• la fig. 2 est une vue schématique en plan de dessus du four et du bac de l'installation de la fig. 1,
• la fig. 3 est une vue également en plan de dessus montrant les voies et les chariots de chargement et de déchargement,
• la fig. 4 est une vue en élévation schématique dans une direction perpendiculaire aux voies de chargement et de déchargement,
• la fig. 5 est une figure en élévation analogue à la fig. 1 montrant l'élévateur d'enfournement dans une position intermédiaire,
• la fig. 6 est une vue semblable à la fig. 1 d'une deuxième forme d'exécution de l'installation selon l'invention,
• la fig. 7 est une vue en plan de dessus de cette deuxième forme d'exécution,
• la fig. 8 est une vue en élévation selon la flèche A de la fig. 7,
• la fig. 9 est une vue schématique semblable à la fig. 1 montrant une troisième forme d'exécution,
• la fig. 10 est une vue en plan de dessus analogue aux fig. 2 et 7 montrant la troisième forme d'exécution, et
• les fig. 11, 12 et 13 représentent respectivement en plan de dessus, en élévation selon la flèche A et en élévation/coupe selon la flèche B une forme d'exécution munie d'un perfectionnement.

Several embodiments of the installation according to the invention will be described below, by way of example, with reference to the attached drawing,

• fig. 1 is a schematic elevation view seen in the direction of the parallel loading and unloading tracks,
• fig. 2 is a schematic plan view from above of the oven and of the installation bin of FIG. 1,
• fig. 3 is also a top plan view showing the loading and unloading tracks and carriages,
• fig. 4 is a schematic elevation view in a direction perpendicular to the loading and unloading tracks,
• fig. 5 is a figure in elevation similar to FIG. 1 showing the rack elevator in an intermediate position,
• fig. 6 is a view similar to FIG. 1 of a second embodiment of the installation according to the invention,
• fig. 7 is a top plan view of this second embodiment,
• fig. 8 is an elevational view along arrow A of FIG. 7,
• fig. 9 is a schematic view similar to FIG. 1 showing a third embodiment,
• fig. 10 is a top plan view similar to FIGS. 2 and 7 showing the third embodiment, and
• fig. 11, 12 and 13 represent respectively in top plan, in elevation along arrow A and in elevation / section along arrow B an embodiment provided with an improvement.

The installation shown in the drawing is a simple installation which comprises only an oven and a tank, for example a quench tank. It is an installation allowing various treatments such as austenitization, case hardening, accelerated case hardening, carbonitriding, nitriding, annealing, tempering.

In the installation of fig. 1, we first see an oven 1 which is a bell oven 2, the latter having at its base an opening 3 limited by a belt 4 whose role will be explained later. Heating bodies 5, a turbine 6 and a double jacket 7 ensure the uniformity of the speeds of the treatment gases in the charge by forced circulation inside and around the bell 2. The oven 1 is mobile from right to left and from left to right in the plane of the drawing in fig. 1. For this, it is carried by rollers 8, which roll on a track designated by 9 in FIG. 4.

When it is located in the position of fig. 1, the oven 1 can be closed by means of a plug 10 which is supported by the plate 11 of an elevator 12, guided by two columns 13 (see fig. 4) and driven by a screw 14, actuated by a motor 15. The control of the motor 15 thus makes it possible to hermetically close the oven 1. These conditions allow a rapid rise in temperature of the load, this by convection and radiation of the heating energy, dispensed by the heating bodies and thanks to the turbine for forced circulation of process gases. This solution has the advantage of ensuring high-precision heat treatment where the temperature dispersions throughout the load will not be greater than ± 5 ° C.

Likewise for the homogeneity of the gas speeds of the treatments in the charge by forced circulation through the double jacket.

When moved to the left in fig. 1, the oven 1 is located above a quench tank 16, rectangular in plan, closed by a cover 17 and which contains an elevator 18 consisting of a vertical guide column 19, a screw d drive 20, a support arm 21 and a plate 22. Inside the tank, are placed guide plates 23 delimiting a channel which allows a homogeneous flow of the coolant through the charge by the '' Circulating pumps or stirring pumps. As seen in fig. 2, the cover 17 is provided with an opening 24 through which the plate 22 of the elevator 18 can pass.

To ensure the transport of the load, provides two carriages, namely a loading carriage 25 and an unloading carriage 38. The carriage 25 rolls by means of rollers 16 on a loading track comprising two parallel rails 27 (fig. 2), located at the base from the bin, next to it. It comprises a box 28, and at its upper part a support 29 in the form of a semicircle capable of receiving a base grid 30 of a load 31 made up of loose parts in stacked baskets. An eccentric device 32, maneuvered by a lever 33, makes it possible to lower or slightly raise the box 28 relative to the chassis on which the rollers 26 pivot, which makes it possible to deposit a load transported by the loading carriage on the inner flat surface of the plug 10 placed on the plate 11 brought to the lower position. This transfer operation being carried out, it is understood that the loading carriage 25 can be evacuated and that the elevator 12 can be driven so as to bake the load 31 and at the same time to close the oven by means of the plug 10. The box 28 and the carriage 25 are also visible in FIG. 4 which illustrates the movement of the lever 33 allowing the transfer of the load from the carriage 25 to the plate 11 of the loading elevator.

Fig. 5 illustrates the operation of transferring the charge after a heat treatment at high temperature and under a controlled atmosphere. The elevator 12 is actuated so as to be placed in an intermediate position between the closed position of the oven visible in FIG. 1 and the lower loading position described above. In this intermediate position, the plug 10 is extracted from the bell of the oven and its flat upper surface is flush with the upper plane of the cover 17 of the tank 16. The oven is then moved from right to left in FIG. 5, the rollers 8 rolling on the rails 9, so that the base belt 4 pushes the base grid 30 on the internal face of the plug 10 and slides this grid until it reaches the cover 17. The displacement of the oven continues until the grid 30 is on the upper face of the plate 22 of the elevator 18 which has been brought into a position where this upper surface is also flush with the surface of the cover 17. Thus , the load is brought immediately above the quenching tank while remaining confined inside the oven bell and therefore protected from the outside atmosphere. It is therefore sufficient to maneuver the elevator 18 so as to bring the load down into the tank, then return the oven to its initial position and close it by means of the elevator 12 and the plug 10. This part of the The installation is therefore ready for a new loading carried out by means of the carriage 25 and the elevator 12.

Once the quenching operation is complete, the elevator 18 is again actuated so as to bring the load into a drip position represented by 31 ′ in FIG. 5. The unloading carriage which also includes a base in the form of a semicircle and which is carried by three rollers 35 mounted on the two rails 36 and 37 is then brought into the unloading position. By slightly lowering the platform of the elevator 18, the load 31 comes to rest on the base of the carriage 38. The latter can be evacuated to the unloading station once the elevator 18 has been lowered into the interior Tray.

A manual or motorized transfer then routes the load to a washing machine or to a next treatment cell, or to an evacuation ramp.

We understand that by using only two parallel transport tracks, one for loading and the other for unloading, one can provide along this pair of tracks a series of installations each with an oven, a tank and a loading elevator, the relative arrangement of these elements being that described above.

Figs. 6, 7 and 8 show a second embodiment in which there is, for the tank and for the oven, the same arrangement as in the first embodiment, but the elevators of the tank and the oven are arranged in a little different so as to make better use of the available space.

We therefore find an oven 1 with a bell 2 and a quenching tank 16. The latter is arranged in a lower and fixed position while the oven 1 is placed in an upper position and movable laterally so that it can be brought alternately to- above the tank 16 or above a loading elevator which is designated here by 39. As in the first embodiment, the elevator 39 carries the plug 10 of the oven. It comprises a horizontal arm 40 fixed to the end of a perpendicular arm 41 which is itself guided in overhang by a column 42 and driven vertically by a jack 43. FIG. 8 shows the vertical arrangement of the guide column 42 and the jack 43. A similar column 44 and a jack 45 are arranged immediately next to the elements 42 and 43 but inside the enclosure of the tank 16. The jack 45 actuates an arm 46, fixed to a transverse arm 47 which supports a plate 48 similar to the plate 22. The assembly 44, 45, 46, 47 and 48 constitutes an elevator 49 placed inside the container 16 in a manner similar to the elevator 22.

We still see in fig. 6 means 50 which ensure the circulation of the quenching liquid inside the tank 16. These two circulators 50 are located in the outside corners of the tank.

Figs. 9 and 10 show a third embodiment illustrating an installation according to the invention and constructed with an oven of rectangular shape and a tank also of rectangular shape. The oven 51 is moreover of similar construction to the oven 1 while the tank 52 comprises elements similar to those of the tank 16.

The improved embodiment, which can be seen in FIGS. 11, 12 and 13, is distinguished by different features.

An oven 61 movable horizontally on a structure 62, a charging elevator 63 and a tray 64 constitute the main elements of this installation.

The oven 61 moves horizontally on two parallel rails 65 and 66 so as to pass from a position above the elevator 63 to a position above the tank 64 and vice versa.

A horizontal plate 67, the upper face of which is flat, extends above the container of which it forms the cover and below the location occupied by the oven during charging. This plate has a circular opening 68 centered relative to the plate 69 of the elevator 63. The elevator 63 carries a hydraulic piston (not shown) which makes it possible to move the plate 69 and the plug 71 relative to the arm of the elevator , actuated itself by a jack 78 and guided by a column 76. The grid 72 supporting the load 73 is carried by the plate 69. A cylindrical mantle 74 in the form of a bowl surrounds the plate 69. It is mounted on the arm of the elevator.

During a charging operation the cylinder 78 is actuated to raise the elevator until the upper edge of the mantle 74 abuts against the underside of the cover 67. The grid is then at the height of the sliding plane. The piston 70 is controlled so that the seal 69, as well as the plug 71 and the load 73 pass through the opening 68. The plug seals the lower opening of the oven, to allow the temperature rise and the heat treatment parts (position in dashed lines in Figures 12 and 13). The mantle 74 is then abutted by its upper edge against the cover 67. It ensures a sealed closure of the oven 61 even when the plug is not in its fully closed position. This sealing effect makes it possible to shift the load on the sliding plane defined by ribs of the plug 71 and of the cover 67 without risk of oxidation of the parts, although the plug is then in an intermediate position.

Coat 74 can be made in different ways. It can consist of two parts which telescope or a single part, as shown in the drawing. It can be moved by one or more cylinders. The mantle can also be constituted by a flexible metallic fabric capable of deforming according to the position of the elevator, in order to seal the opening 68 of the sliding plate in a leaktight manner when the load is shifted with the entire oven. to be slid onto the tray 75 (fig. 11) of the tank elevator.

Note in the embodiment of Figs. 11, 12 and 13 that the columns 76 and 77 as well as the cylinders 78 and 79 for controlling the elevators are devices grouped close to one another at the rear of the installation. It is very compact and has a minimum number of elements.

• 1. Au moyen de trois dispositifs motorisés seulement, l'ensemble des transferts pour l'ensemble des traitements est assuré avec toute la souplesse nécessaire.
• 2. Durant tout le traitement, la charge est protégée par l'atmosphère de traitement, soit dans le four, soit dans le bac.
• 3. Le four à cloche peut être un four à haute température et du fait que son ouverture est située à la base de la cloche, la température et la circulation des gaz sont homogènes.
• 4. L'ensemble de l'installation occupe une surface au sol très réduite.
• 5. Un même moyen de chargement et de déchargement, à commande manuelle ou éventuellement motorisée, permet de faire travailler plusieurs unités de traitement composées chacune d'un four, d'un bac ou de deux bacs et d'un élévateur de chargement, ce dernier pouvant, le cas échéant, être mobile.
• 6. La charge est supportée par un plateau tout au long de l'opération et il n'est donc pas nécessaire de prévoir un moyen d'accrochage pour un transfert suspendu sur le bac de refroidissement.
• 7. La conception générale du système est très simple tout en étant souple, ce qui réduit les frais d'installation.
• 8. L'ensemble de l'installation peut facilement être automatisé ou informatisé.

The facilities described above have many advantages over existing facilities:

• 1. By means of only three motorized devices, all transfers for all treatments are provided with all the flexibility required.
• 2. During the whole treatment, the load is protected by the treatment atmosphere, either in the oven or in the tank.
• 3. The bell oven can be a high temperature oven and the fact that its opening is located at the base of the bell, the temperature and gas circulation are homogeneous.
• 4. The entire installation occupies a very small floor area.
• 5. The same loading and unloading means, manual or possibly motorized, allows several processing units to work, each consisting of an oven, a tank or two tanks and a loading lift, the latter can, if necessary, be mobile.
• 6. The load is supported by a plate throughout the operation and it is therefore not necessary to provide a hooking means for a transfer suspended on the cooling tank.
• 7. The general design of the system is very simple while being flexible, which reduces installation costs.
• 8. The entire installation can easily be automated or computerized.

Claims (10)

1. An installation for the heat treatment of successive batches, comprising a vertically disposed furnace (1) in an upper position having an open bottom, a vat (16) equipped with a lift (18) and placed in a lower position, a horizontal access track mounted at the level of the bottom of the vat (16) and fitted with loading means, and a loading lift (12) disposed at a side of the vat (16) in such a manner as to lift a batch (31) loaded onto the lift (12) by the loading means into the furnace (1), the furnace (1) being horizontally mobile between a position above the loading lift (12) and a position above the vat (16), characterised by a sliding plane which is disposed at the level of the furnace bottom and allows to shift a batch (31) supported by the loading lift (12) by displacement of the furnace (1).
2. Installation according to claim 1, characterised in that the loading lift (12) carries a plug (10) capable of sealing the furnace (1), and in that the plug (10) has a flat surface for supporting the batch (31).
3. Installation according to claim 2, characterised in that the furnace (1) is a furnace having a bell whose bottom is designed in such a manner as to laterally push a supporting grid (30) of a batch (31) in order to displace it on said supporting surface, the plug (10) being in an intermediate position when the furnace (1) is displaced from the position above the loading lift (12) to the position above the vat (16).
4. Installation according to claim 3, characterised in that the vat (16) is provided with a cover (17) having an opening (24) for a platform (22) of the lift (18) of the vat (16) to pass through, and in that the upper surface of the cover (17) forms a part of said sliding plane.
5. Installation according to claim 4, characterised in that the cover (17) of the vat (16), the platform (22) of the lift (18) of the vat (16), and the surface of the plug (10) form, when the plug (10) is in its intermediate position, said sliding plane on which the base grid (30) is slidingly displaced when it is pushed by the base of the bell (2) of the furnace (1).
6. Installation according to claim 5, characterised in that the elements of the sliding plane comprise a gastight surface between the bell (2) and the sliding plane when the batch (31) is translated.
7. Installation according to claim 2, in which the loading means comprise cars (25, 38), characterised in that the cars (25, 38) are provided with platforms (22) capable of limited vertical displacement, allowing a grid (30) supporting a batch (31) to be transferred respectively from a platform of a loading car (25) over the plug (10) of the furnace (1), or from the lift (18) of the vat (16) onto a platform of an unloading car (38).
8. Installation according to claim 7, characterised in that the platforms of the cars (25, 38) each have a semi-circular opening.
9. Installation according to claim 7, characterised in that the platforms of the cars (25, 38) are supported by an eccentric device (32) allowing said limited displacement by means of the action of a lever (33).
   (without priority)
10. Installation according to claim 1, characterised in that the loading lift (12) is fitted with a sealing device which is capable of preventing any air from entering the furnace (1) when said loading lift (12) carries a batch (31) at a level where its bottom surface is at the level of the sliding plane.

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