DE8400891U1 - Heating module - Google Patents

Description

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Hanau, January 11, 1984 ZPL-Gä / ha

WC. Heraeus GmbH Usage meter registration

»Heating module"

The innovation relates to a heating module in the form of a pipe or a pipe half-shell, which has a support body made of insulating material, which consists essentially of ceramic fibers, and in which an electrical heating conductor is arranged at a distance from the carrier body.

Heating modules with a carrier body »which essentially consists of ceramic fibers are known. The conference documents from Bulten-Kanthal GmbH, Mörfelden-Walldorf, distributed on the occasion of the conference of the German furnace industry from 8.-9. March 1983 in Bad Soden / Ts. it can be seen that heating modules made of vacuum-formed ceramic fibers with molded-in heating elements in the electrical heating area from laboratory ovens to large ones Industrial furnace can be used. The heating elements can have the form of plates, half-shells and tubes.

In the known devices, the heating conductors are direct embedded in the thermally good insulating material, which can result in local overheating of the heating conductor * This overheating can lead to greater shrinkage of the fibers in the area of the overheating point to thermal lengths » stretching up to permanent deformation of the heatsealing band.

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> 1 unfavorable cases, the mechanical fastenings Break the heating coil out of the fiber insulation.

Furthermore, it is known from the above-mentioned conference documents, to use oval helix in plates, half-shells and tubes * which only have a relatively small area are embedded in the fiber material per turn, while the remaining area of the helix radiates freely in the direction of the usable space is executed. With such an arrangement, the freely radiating parts of the helix are mechanically and chemically increased Exposure to stress, e.g. from pollution from the usable space and from aggressive media. When The entire heating module must then be replaced will.

From DE-PS 28 31 151 it is known that the above-described Compensate for shrinkage in the fiber material by means of depressions in the molded body. So it is possible in front of the thermally insulating Material heating conductor to be arranged with the help of separate fastening elements in the form of a tube or bar, facing towards the usable space shine. Due to increased stability requirements, such radiant heating conductors are relatively large Conductor cross-section provided and therefore only suitable for low-voltage operation. This results in complex electrical supply systems with transformers and enlarged connection cross-sections. The heating conductors are also exposed to increased mechanical and chemical stresses from the area of the usable space «

The innovation is the task of a heating module with a carrier body made of vacuum-formed ceramic fibers build in which the electrical heating element has a high mechanical stability with uniform heating and can be locked directly to the power supply network.

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Furthermore, the heating conductors should be easy to change to be possible"

The object is achieved in that the carrier body has a one directed in the direction of the pipe axis at its two ends Web has that the support body and the web form a structural unit, and that the web has at least one hole at one end has, in which the electrical heating conductor is mounted, which is arranged in a ceramic tube.

In a preferred embodiment, the heating conductor is located in a ceramic tube, which is through a bore in a

- Forming an end face - circumferential web is guided, while the ceramic tube with its other end through a recess is held in a second circumferential web, which is the other end face of the tubular support body forms.

According to the arrangement according to the invention, a relatively fast heating-up time proves to be advantageous the low heat capacity of fiber material and ceramic tube. Furthermore, the heating element is against corrosion by agressiue Media and contamination protected by splashes from the area of the usable space.

The following is the subject of the innovation based on the figures 1 and 2 explained in more detail. Figure la shows a longitudinal section of a heating module according to the innovation with a support body in the form of a tube, while in Figure Ib its cross section is shown. Figure shows a heating module with a support body in the form of a Half shell.

Figure la shows in longitudinal section a heating module with a support body in the form of a tubular jacket 1 made of vacuum-formed fiber material, iti the upper half of the figure

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a heating element with a ceramic tube 2 'closed on one side is shown, while in the lower half of the Figure shows a heating element with a ceramic tube 2 ″ open at both ends. The two partial figures represent different forms of execution, which are only used for the purpose of angry Overview appear in a common figure

Aluminum silicate and / or aluminum oxide is preferably used as the fiber material of the carrier body. The ceramic tube the heating elements are made of aluminum silicate and / or aluminum oxide material. Your wall thickness is in the range from 0.5 to 3 mm. In the ceramic tubes there are helical ones Housed heating conductors, which consist of a chrome-iron-aluminum alloy. Preferably an alloy of 22% chromium, 5.5? Ί aluminum, the remainder iron is used.

According to FIG. 1 a, the ceramic tube 2 'is guided through a bore 3' in a circumferential web 4 forming the end face of the tubular casing 1, while its closed end 5 is in a blind hole-like recess 6 in the circumferential web forming the other end face of the casing 1 7 rests. The webs 4, 7 each have the shape of a ring; they consist of the same material as the tubular jacket 1. In the area of the longitudinal axis 15 of the tubular jacket 1, the webs 4, 7 are provided with circular openings 13, 14 through which the material to be heated can be brought in and out. The openings can be closed. It is also possible to design the web 4 so that the opening 13 is largely or completely closed. The helical heating conductor 8 'accommodated in the ceramic tube 2 ¹ is supplied with power via the connections 9' and 10 '. The connection conductor 10 'provided for the return line is ^{guided over the full length of the ceramic tube 2 1} through the helical heating conductor 8 ·; it is closed by a U-shaped contact loop ^{11 with the heating conductor 8 1}

End 5 of the heating element connected. Since the connecting conductor 10 'is in a ceramic tube in the region of the longitudinal axis of the turning egg 16 is located, the possibility of short circuits between connecting conductor 10 'and heating conductor 8 · is excluded.

In the event of a defect in the heating element, the entire element with ceramic tube 2 'and heating conductor 8 * removed through the bore 3 'and exchanged for a new heating element.

In the lower half of FIG. 1 a, a heating element with a ceramic tube 2 ″ that is open at both ends is shown. The ceramic tube 2 "is located with one end in the bore 3" of the annular circumferential web 4, while it is with his the other end in the bore 12 of the other circumferential web 7 rests. The heating conductor 8 ″ consists of a ceramic tube 2 "located coil, which is provided on the end faces of the ceramic tube 2" with the connections 9 "and 10" is.

If the heating element is defective, this can be done easily Way by disconnecting the electrical connections and then pulling out the ceramic tube with heating conductor a new heating element must be replaced. However, it is also possible to just pull the heating conductor 8 "out of the ceramic tube 2" of the heating element and insert it through a to replace a new heating element.

Figure Ib shows a cross section through the pipe axis according to the section line a-b in Figure la.

In section a-b, the fiber material produced by vacuum forming can be seen, which the insulating mental 1 of the Forms heating module. Within this jacket 1, the heating elements are in a concentric manner at regular intervals

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Arranged in a circle, the annular circumferential web 7 serves to hold the ceramic tubes 2 of the heating elements. The arrangement shown in this figure is suitable for both embodiments according to Figure la. The to this Reference numbers 2 mentioned in the figure apply both to ceramic tubes which are closed on one side and to ceramic tubes which are open on both sides.

The shape of a carrier body shown in Figures la and Ib with a circular cross-section was chosen for the sake of clarity. It is of course possible, too Build support body with an oval pipe cross-section or an approximately square pipe cross-section.

Figure 2 shows a heating module according to the innovation in the form of a tubular half-shell. This arrangement corresponds in principle the heating module known from FIGS. 1 a and 1 b, wherein the cylindrical module is halved along the cylinder axis became. For a better overview, only four heating elements with their ceramic tubes 2 are shown in this figure. they are guided at one end in a bore 3 of the semicircular web 17. At the other end are the ceramic tubes according to Figure la either closed on one side or open. The heating elements closed on one side rest accordingly the ceramic tubes 2 'from Figure la in a blind hole-like recess 6 of the semicircular web 18, while the Heating elements open at the ends, corresponding to the ceramic tubes 2 ″ from FIG. 1 a, are held in the web 18 by a bore 12 will.

The use of heating modules according to Figure 2 is particular suitable for hinged ovens, such as those used to accommodate large compact workpieces are required.

Claims (7)

Hanau, January 11, 1984 ZPL-Ga / ha W.C. Heraeus GmbH utility model registration "heating module" protection claims 1. Heating module in the form of a pipe or a pipe half-shell, which has a carrier body made of insulating material, which consists essentially of ceramic fibers, and in which an electrical heating conductor is arranged at a distance from the carrier body, characterized in that the carrier body at both ends has a web (4, 7, 17, 18) directed in the direction of the pipe axis (15), that the support body and web form a structural unit, and that the web has at least one bore (3, 3, 3 ") at one end, in which the electrical heating conductor (8 ', 8 ") is mounted, which is arranged in a ceramic tube (2, 2 ¹ , 2"). 2. Heating module according to claim 1, characterized in that the ceramic tube (2, 2 ^{1 , 2 ") containing the heating conductor (8 1} , 8") which passes through the bore (3, 3 ', 3 ") in the first web ( 4, 17) is guided 1st, is held in the second web (7, 18) in a receptacle (6, 12). 3. Heating module according to claim 2, characterized in that the heating conductor (8 ¹ ) is in a ceramic tube (2 ¹ ) with a closed end (5), the closed tube end (5) in a blind hole-like recess (6) in the web (7, 18) rests. 4. Heating module according to claim 2, characterized in that the recess in the web (7, 18) as a through hole is formed and the ceramic tube is held both in the recess (12) and in the bore (3, 3 "). 5. Heating module according to one of the preceding claims, characterized in that the wall thickness of the ceramic tube (2, 2 ¹ , 2 ") is in the range from 0.5 to 3 mm. 6. Heating module according to one of the preceding claims, characterized in that the material of the carrier body consists of Aluminum silicate and / or aluminum oxide fiber material and the ceramic tube (2, 2 ', 2 ") made of aluminum silicate and / or alumina material. 7. Heating module according to one of the preceding claims, characterized in that the heating conductor (8 ^!, 8 ") consists of a Chroiti-iron-aluminum alloy. • t It
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