DE3619343A1 - Heat-treatment furnace with local heating chambers - Google Patents

Abstract

A heat-treatment furnace has a furnace body with an inlet and an outlet. A support charged with material being treated is transported by a transport arrangement from the inlet to the outlet. Situated above the transport path of the supports is a number of local heating chambers. Situated below the transport path in places relating to the heating chambers are lifting devices. In the course of passage through the furnace, the support reaches the place below the respective local heating chambers and is there lifted by the lifting device concerned. The support thus raised blocks the opening section formed in the underside of the local heating chamber, while the material being treated is situated on the support inside the heating chamber. In this state, the material being treated is heated by a heating device situated in the chamber. After completion of the heat-treatment operation, the support with the material being treated is lowered in order to be transported to the next local heating chamber. There, the support is again raised by the lifting device so that the material being treated is treated in the heating chamber. In this manner, the material being treated is subjected to various heat treatments until the material being treated leaves the furnace on the support.

Description

description

The invention relates to a heat treatment furnace, with the help of which an item to be treated by heat treatment heating devices provided in the furnace can be subjected while the material to be treated from an inlet of the furnace to whose outlet is transported.

A heat treatment furnace has already been developed by the inventors, which has approximately the following structure: At one end of an elongated furnace body an inlet or a feed point is provided, at the other end is an outlet or a withdrawal point. Inside the furnace there is a transport device, with the help of which the material to be treated coming from the inlet in the direction of the outlet is transported. The space inside the stove is in through closable doors Sections divided so that several chambers in the direction of transport of the material to be treated are formed. Each chamber has a heater.

In such an oven, the material to be treated coming from the inlet becomes heated by the respective heating devices in the individual chambers while the material to be treated is moved by the transport device and through all Chambers runs until it finally reaches the outlet.

However, the following problems arise with such an oven: Not only the material to be treated, but also the transport device is inevitably heated, so that the transport device requires protection against high temperatures. This leads to a complicated construction. The heat treatment takes place in relatively large chambers, which are separated from one another by the doors.

The transport arrangement absorbs within the individual chambers the heat, so that the entire system works relatively uneconomically. For the Heating requires a relatively large amount of thermal energy. As mentioned, takes the transport device heat continues, with the result that within the chambers results in an uneven, sometimes abrupt temperature profile. Through this the quality of the heat treatment of the items to be treated is impaired.

It is the object of the invention to create a heat treatment furnace, with the help of which an item to be treated in the course of its transport through the furnace can be subjected to a series of heat treatments.

This object is achieved by the invention specified in claim 1. Advantageous further developments result from the subclaims.

The present invention provides an oven in which the transport assembly can be protected against high temperatures with simple means, while at the same time the material to be treated is subjected to a heat treatment.

The heat treatment is carried out in the course of the transport of the material to be treated carried out. The heat treatment furnace according to the invention requires comparatively little thermal energy, while at the same time improving the quality of the heat treatment is.

When the material to be treated is heat-treated in the oven according to the invention the goods remain on the carrier (which is e.g. a board can) while the material to be treated is fed into the oven via the inlet.

The item to be treated located on the carrier is transported by the transport arrangement transported to the area below a local heating chamber where carriers and treatment lifted well together by the lifting device will.

As a result, the material to be treated gets into the local heating chamber, while at the same time the carrier one in the bottom of the local heating chamber formed opening section blocked adiabatically. The item to be treated is in this state heated by the heater in the local heating chamber. After completion the heat treatment, the item to be treated is lowered together with the carrier and brought by the transport device under the next local heating chamber, where the carrier and the material to be treated are raised in a similar manner and after the heat treatment of the items to be treated are lowered again. These operations take place at every local Heating chamber instead, so that overall the material to be treated a series of heat treatments is subjected. The material to be treated then arrives on the carrier via the outlet out of the oven.

As explained above, the carrier, which is designed as a panel, blocks the opening portion of the respective local heating chamber. The transport arrangement is therefore practically not affected by the high temperatures inside the heating chamber influenced. This is a special feature of the invention. By the construction according to the invention is an easy and simple protection of the transport device created against high temperatures, so that the overall structure is greatly simplified is.

When the material to be treated undergoes heat treatments at high temperatures is exposed, the material to be treated is in the respective local heating chamber, while the support panel has the function of adiabatically closing the opening portion To block. So you get the economic advantage that only one relative small amount of thermal energy is required in small rooms, the means in the local heating chambers, an effective heating of the material to be treated to reach.

Since you? Support board the opening portion of the local heating chamber adiabatically locks the thermal seal in the local heating chamber created space improved. This has the consequence that the heat treatment of the material to be treated A high product quality is guaranteed by placing a cheap one within the chambers Temperature profile is reached.

In the following, exemplary embodiment of the invention will be described with reference to the drawing explained in more detail. The figures show: FIG. 1A a longitudinal sectional view of a sintering furnace according to the invention with a degreasing chamber, a sintering chamber and a vacuum cooling chamber, Fig. 1B is a sectional view of the sintering furnace with a gas cooling chamber and a Substitution chamber, FIG. 2 shows a sectional view along the line II-II in FIG. 1A, and FIG. 3 is a partial sectional view taken along the line 111-111 in FIG. 1A.

The figures, of which FIGS. 1 A and 1 B belong together, show a heat treatment furnace for sintering an item to be treated under vacuum. The sintering furnace 1 contains a hollow furnace body 2, which is designed here as a vacuum container. The furnace body 2 contains a degreasing chamber 3, a sintering chamber 4, a vacuum cooling chamber mer 5, a gas cooling chamber 6 and a substitution chamber 7.

The vacuum container 2 is made of metal and is designed in such a way that that each chamber can be separated from the other chambers. The vacuum container can be water-cooled if required. The respective chambers are divided by partition walls 8 completely separated from each other.

The furnace has a loading opening or an inlet 9, a discharge opening or an outlet 10 and a plurality of connecting passages 11. All of these openings can be opened and closed by sliding doors 12, 13 and 14. The doors each have a locking device 15. On the vacuum container 2 are (not shown) guide members attached, with the help of sliding frame 16 along predetermined tracks can be raised and lowered. This is done with help of lifting devices (e.g. air cylinders) 17. Parallel rods are attached to the sliding frames 16 18 hinged. In the locking devices 15 constructed in this way, each of the sash frames 16 can be lowered with the aid of the associated lifting device 17. In the lowered State is the door 12 (or 13 or 14) of the loading opening 9 (or the removal opening 10 or the connecting passage 11) opposite, while the lower portion of the Door is received by a (not shown) receiving member, so that cannot lower the door any further. If the sash frame is lowered further 16 in this state, the door frame is against the perimeter of the respective opening (Feed opening 9, removal opening 10 or connecting passage 11) pressed, so that the interior of the vacuum container 2 is sealed.

The individual chambers formed by the partition walls 8 are hermetically separated from each other. When the sash 16 goes up, it disappears first the above mentioned pressing force, and then the moves Door together with the sash 16 upwards, so that the relevant opening is released.

A transport arrangement consists of transport rollers 20.

Each transport roller 20 has, as shown in FIG. 2, a shaft 22 which passes through a bearing 21 is mounted on the vacuum container 2, as well as mounted on the shaft 22 Receiving members 23. One end of the shaft 22 protrudes through a seal 24 the vacuum container 2. At this end is via a connecting device 25, e.g. a chain or the like, a drive device 26 coupled.

The degreasing chamber 3 contains one attached to the vacuum container 2 local heating chamber 30. The local heating chamber 30 has in its interior a receiving space 31 for the item to be treated. On the lower side is an opening portion 32. This local heating chamber 30 consists of, for example, a adiabatic material such as graphite or the like. The inner surface is like this designed and arranged that the radiant heat is reflected favorably. One Heater 33 is located inside the heating chamber 30. In the present case For example, a heating wire is used as the heating device. The two ends of the Heating wires are connected to electrodes 34 which are attached to the vacuum container 2 are. An infrared lamp, for example, can also be used as the heating device. A thermometer 35 attached to the vacuum container 2 is used to measure the temperature within the local heating chamber 30. A viewing window 36 enables monitoring of the interior of the local heating chamber 30.

A hoist is located below the local heating chamber 30 28. A fluid cylinder 40 (a hydraulic cylinder or a Air cylinder) with Installed using a mounting frame 39. One Piston rod 41 received in cylinder 40 protrudes through a seal 42 into the Inside of the vacuum container 2. The free end of the piston rod 41 is U-shaped Lifting link 43 equipped. The two free ends 43a of the whisk 43 are like this designed that they enforce the distance between adjacent transport rollers can be raised.

The sintering chamber 4 is, like the degreasing chamber, in its interior equipped with a local heating chamber and also with a lifting device. Since the sintering chamber 4 has essentially the same structure as the degreasing chamber, Identical or similar reference symbols are used in the drawing for this purpose. On a repeated description of the same or similar parts is dispensed with. In the Sintering chamber 4 must treat the material to be treated at an extremely high temperature and therefore a wide heating tape is used as the heating device. the local heating chamber 30 itself consists of a material with high thermal resistance, e.g. molybdenum, tungsten or the like.

The cooling chamber has a fan 46, a motor 47, a cooler 48 and a baffle 49. When the fan 46 is rotated by the motor 47, there is a flow the gas located inside the chamber into that indicated in Fig. 1B by arrows Direction. The gas cooled by the cooler 48 comes into contact with the material to be treated and cool it down.

A panel designed as a table 50 serves to receive the items to be treated Carrier. The panel has a rack frame 51, a heat shield 52, a Cover plate 53 and a receiving plate 54. These components are in the figure as at a certain distance from each other, connected parts shown. The receiving plate 54 serves to receive the items 56 and 56 to be treated consists of a material with high thermal resistance. The heat shield 52 as well the cover plate 53 are made of material with high thermal resistance. Of those mentioned Components, the cover plate 53 has a lower part 53a, the area of which is larger is as the opening portion 52 of the local heating chamber 30 so that the plate the chamber 30 can close in a heat-tight manner. On the lower part 53a is located an upper part 53b that enters the inside of the opening portion 32. The lower Part 53a and the upper part 53b have high heat resistance and are at the same time designed to provide adequate thermal insulation. Of the upper part 53b is formed by laminated tungsten plates, the lower part 53a consists of layered molybdenum plates.

The top of a trolley 58 has rollers 59 which the Carrying plaque 50. The trolley 58 moves perpendicular to the plane of the drawing and transports the item to be treated.

The operation of the furnace described above is explained below will. The degreasing chamber 3 has atmospheric pressure, while the sintering chamber 4, the vacuum cooling chamber 5 and the gas cooling chamber 6 are under vacuum when the work flow begins. The board loaded with the material to be treated 56 is first removed from the transport carriage 58 unloaded. The work to be treated 56 contains a substance in which stainless powder is solidified with a per se known binder and / or a substance that is similarly made by using a rare earth metal powder solidified with the help of the same binder. After opening the door 12 is the board 50 through the feed opening 9 onto the transport rollers 20 of the degreasing or dewaxing mer 3 given. Then the door 12 is again sealed, and the degreasing chamber 3 is placed under vacuum.

In this state, the cylinder 40 of the lifting device is actuated, whereby the piston rod 41 rises. The panel 50 is followed by the lifting member 53 raised towards the local heating chamber 30 at the top. This will make that On the receiving plate 54 to be treated 56 in the receiving space 31 in the Arranged inside the chamber 30, as shown in the figure. Simultaneously the opening section 32 is closed by the cover plate 53. In this State, the heating wire 33 is electrically heated. Then the item to be treated 56 heated by the radiant heat radiated from the heating wire 33. This heating process stops at a temperature of 6000C, for example, in order to avoid that in the material to be treated 56 contained wax (binder) to evaporate. The heating process will be long enough maintained in order to completely evaporate the wax contained in the material to be treated. This period ranges, for example, from a few tens of minutes to several hours.

After completing the heat treatment described above, the whisker becomes 43 lowered again by the cylinder 40.

The board 50 loaded with the item to be treated 56 comes up again down on the transport rollers 20. Then the door 14 of the connecting passage 11 is open between the degreasing chamber 3 and the sintering chamber 4. Afterward The board 50 loaded with the material to be treated 56 arrives in the interior of the sintering chamber 4. Then the door 14 is closed. The panel 50 is through the in the sintering chamber 4 arranged lifting device 38 upwards towards the local heating chamber 30 raised, so that the same situation arises as above for the degreasing chamber 3 has been described.

The item 56 to be treated is then radiated by the heating wire 33 Radiant heat is heated. This type of heat treatment continues until the Material to be treated 56 has reached, for example, a temperature of about 20000C, which sufficient that the material to be treated sinters.

The heating can be carried out until the material to be treated 56 has reached the temperature mentioned. This does not require a long heat treatment time needed. In the other chambers, however, e.g. in the degreasing chamber 3 or in the cooling chambers 5 and 6, in which items to be treated are treated at the same time, can the treatment time must be coordinated with the heating time in the sintering chamber, or vice versa, so that a continuous treatment of the material to be treated in the individual chambers is possible.

After completion of the heating process, the panel 50 with the items to be treated 56 lowered back down onto the transport rollers 20. After opening the between the door 14 located in the sintering chamber 4 and the vacuum cooling chamber 5 becomes the panel 50 together with the item 56 to be treated via the transport rollers 20 into the vacuum cooling chamber 5 transported, whereupon the door 14 is closed. The item to be treated 56 is cooled in the chamber 5 to a predetermined temperature. After opening the between the vacuum cooling chamber 5 and the gas cooling chamber 6 located door 14 reaches the Table 50 with the items 56 to be treated, over the transport rollers 20 in the gas cooling chamber 6. After the door 14 has been closed, cooling gas is introduced into the gas cooling chamber 6. The lifter 46 and the cooler 48 are set in motion and thereby cool the items to be treated 56.

The material to be treated 56 cooled in this way to the predetermined temperature reaches after opening the one located between the chamber 6 and the substitution chamber 7 Door 14 over the transport rollers 20 in the substitution chamber 7, whereupon the Door 14 is locked. In the substitution rungskammer 7 is the gas flow coming from the gas cooling chamber 6 is replaced by atmospheric gas. To When the substitution is completed, the door 13 opens and the panel 50 can be put together with the items 56 to be treated, the furnace for further treatment via the removal opening 10 leave.

Between the degreasing chamber 3 and the sintering chamber 4, a further degreasing chambers with the same structure as chamber 3 are provided, so that the degreasing process is divided into two steps. Between the degreasing chamber 3 and the sintering chamber 4 according to FIG. 1, a preparatory sintering chamber can be provided which has the same structure as the sintering chamber 4.

In the preparatory sintering chamber, the material to be treated can be to be pre-sintered at a slightly lower temperature (e.g. at 1600 "C) before then in the sintering chamber described above, sintering at the sintering temperature (from e.g. 20000C).

As a transport device, instead of the described transport rollers other means can also be used.

For example, it can extend over the entire length of the vacuum container 2, a rail arrangement provided on the door 14 with a gap may be provided.

The furnace 1 is used as described above for heating the material to be treated put under vacuum. For this purpose, the items to be treated can be heat-treated the furnace inside can be filled with an inert gas or other gases.

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Claims (3)

Warmbehandlunqsofen with local heating chambers Patent claims 7 1.) Heat treatment furnace, with K a hollow furnace body (2) which has an inlet (9) and having an outlet (19), - a transport arrangement (20) for transporting a carrier (50) loaded with an item to be treated (56) from the inlet (9) the outlet (10), - several local heating chambers (30), which are located along a transport path the carrier is arranged in the furnace body (2) above the transport path, and - Several lifting devices (40-43), on the one hand below the transport track for the carrier (50), on the other hand each below the local heating chamber (30), are arranged, with the local heating chambers in their interior sufficient Have space for receiving the items to be treated (56), open on the underside are and minor at least one heating device (33) for heating the The items to be treated (56) have the lifting devices (40-43) arranged in this way are that the respective carrier (50) can be raised into a position in which it in one or on one in the underside of the respective heating chamber (30) formed opening portion (32) is fitted or adapted, and the carrier (50) has an area sufficient to adiabatically block the opening portion the local heating chamber when the carrier (50) is removed from the lifting device (40-43) is raised. 2. Heat treatment furnace according to claim 1, characterized in that g e -k e n n z e i c h n e t that the interior of the furnace body (2) in the transport direction of the carrier (50) is hermetically divided into several chambers with the help of partition walls (8), that each partition wall (8) has a connecting passage (11) through which through the carriers (56) carrying the material to be treated (56), e.g. are designed as panels, get, and those with lockable Doors are equipped to hermetically seal the connecting passages, and that in the chambers formed by the partition walls (8) several local Heating chambers and several lifting devices (40-43) are provided. 3. Heat treatment furnace according to claim 1 or 2, characterized in that g e k e n n it is indicated that the transport arrangement has several transport rollers (20), which are spaced parallel to each other in the direction in which the Carriers are transported by the transport arrangement, and that each of the lifting devices (40-43) has a lifting arm (41) which has a space between adjacent Transport rollers (20) penetrated.