DE1009732B - Process for the production of flexible electrical heating devices, in particular for de-icing on aircraft, and heating devices produced by the process - Google Patents

Description

GERMAN

The invention relates to a method of manufacture flexible electrical heating devices, especially intended for de-icing on aircraft, as well as electrical produced after this process Heating devices.

It is already known to manufacture flexible electrical heating devices in such a way that the Heating element arranged on special support bodies and embedded between two rubber plates or strips is, the z. B. be firmly connected to each other by welding. In contrast, intended the invention to provide a method and heating devices produced by the method, which are particularly suitable for use in cases where the heating devices, such. B. de-icing on aircraft, exposed to rapidly changing loads and therefore particularly high levels of wear are. In particular, it should be achieved by the invention that in the between the rubber strips embedded heating element in these conditions, e.g. B. when tensioning in the longitudinal direction only slight tensile stresses occur, which do not affect the service life of the heating device.

Accordingly, there is the method of the invention in that first a rubber strip is made, which on one side with a number is provided by also made of rubber protrusions in two or more rows, which are in Extending longitudinally of the strip, thereon a flexible electrical heating element in or around one Projection of a row, then in or around a projection of the adjacent row and around again in or is placed around a projection of the first row, such that the heating element is in the longitudinal direction of the strip runs in a serpentine shape, whereupon finally in a manner known per se for covering of the heating element another rubber strip with the first rubber strip, expediently by welding, is connected.

With a heater manufactured in this way the projections if, for. B. the heater is tensioned in the longitudinal direction, in apart in the longitudinal direction of the heater, but come in the transverse direction of the heater closer together so that the tensile stress on the heating element is reduced to a minimum will. This is e.g. B. for deicing heaters on aircraft of particular importance, as such Heating devices rapidly changing loads of different sizes in almost all directions are exposed and are therefore particularly endangered in their service life.

In one according to the method according to the invention, method of manufacturing flexible

electrical heating devices,

in particular for de-icing on aircraft, and manufactured according to the process

Heating devices

Applicant:
Electrothermal Engineering Ltd., London

Representative: Dipl.-Ing. W. Paap, patent attorney,
Munich 22, Mariannenplatz 4

Claimed priority:
Great Britain 9 August 1954

Henry Herbert Goldstaub

and Walter Standing, London,

have been named as inventors

manufactured heater, the projections can be mushroom-like, and the flexible electrical Heating element can be wrapped around the lower part of the mushroom-like protrusions below the heads. The front jumps can also have a cylindrical shape and at their free end with a Be provided with a slot in which the flexible electrical heating element is inserted.

The projections of one row are preferably staggered with respect to the projections of the adjacent row arranged. Furthermore, at least two pairs of rows of projections can be arranged in such a way that the distance between the two pairs of rows is equal to or greater than the distance between the rows of a row pair. The projections can in this way according to the present Needs to be arranged so that an even or uneven heating per unit area is achieved.

The rubber strip carrying the projections can, like the rubber strip serving for covering consist of natural or artificial rubber, while the flexible electric heating element by a bare wire or a strand of wire can be formed. A bare wire can also be used which is spirally wound on an insulating core.

In the drawing there is one according to the new process manufactured flexible electric heater for example illustrated.

709 547/339

Fig. 1 shows a rubber strip with protrusions in elevation;

FIG. 2 is a section along line AA of FIG. 1.

The flexible electrical heating device is formed from a long, flat rubber strip 1 which has the shape shown in FIG. The strip has two parallel pairs of rows of projections I ₁ which extend in the longitudinal direction of the rubber strip. Each pair of rows of projections consists of two parallel rows, the projections in one row being spaced apart from the projections in the other row. The two pairs of rows are arranged such that the distance between the two pairs of rows is greater than the distance between the rows of a pair of rows or this distance is approximately the same. A flexible electric heating element 3 is alternately looped around a protrusion of each row of a pair of rows so that it extends in a serpentine shape in the longitudinal direction of the strip. The heating element is then wrapped around the projections of the second pair of rows in a similar manner. The two free ends 5 of the heating element are used to attach terminals.

In the illustrated embodiment, the projections have a mushroom shape, they So they have a flat, disk-shaped head 4 and jump back below the head, so> that the heating element can be wrapped around the lower part of the projection and the head of the pre-jump extends over the heating element, holding it in place.

After the heating element is attached to the strip 1 in the manner described, the strip placed in a mold and a cover layer of rubber on the protruding strips molded to cover the projections. It is essential to have a solid connection between the protruding strips and the cover layer ensure what is expedient by Welding is achieved.

Claims (5)

Patent claims: 1. A method for producing flexible electrical heating devices, in particular for de-icing on aircraft, in which the heating element is attached between two rubber strips expediently connected to one another by welding, characterized in that a rubber strip is first produced, which is also made on one side with a number of rubber existing protrusions in two or more rows is provided, extending in the longitudinal direction of the strip, thereon a flexible electric heating element in or near a \ ⁷ brsprung a row, then in or near a protrusion of the adjacent row and get back in or near a Projection of the first row is placed in such a way that the heating element runs serpentine in the longitudinal direction of the strip, whereupon a further rubber strip is connected to the first rubber strip, expediently by welding, in a manner known per se to cover the heating element. 2. Nadh the method according to claim 1 produced heating device, characterized in that that the projections are mushroom-like and the flexible electrical heating element around the lower part of the projections is wrapped around below the heads. 3. Heating device produced by the method according to claim 1, characterized in that that the projections are cylindrical and provided with a slot at their free end in which the flexible electrical heating element is inserted. 4. Heating device nadh claim 2 or 3, characterized in that the projections one Row to the projections of the adjacent row are arranged on a gap. 5. Heating device according to one of claims 2 to 4, characterized in that at least two pairs of rows of projections are arranged so that the distance between the two pairs of rows is equal to or greater than the distance between the rows of a pair of rows. Considered publications:
German patent specifications No. 631 871, 873 881. 1 sheet of drawings © 709,547 / 339 5.57