Seal.

The invention relates to a seal for static applications with a non-metallic base body for sealing two flanges at temperatures above 500 ° C, preferably for hot continuous exhaust pipes. Such trained as gaskets seals with a base body made of pure graphite or asbestos, which typically includes a stiffener, which is formed by a perforated metal sheet or a metal mesh are known. Besides the fact that efforts are being made to replace asbestos by other materials, these known seals well over 500 C. could not provide the required creep strength and sealing performance in all applications, particularly when used at temperatures The leak is caused, inter alia, that the flanges (and screws) temperature-dependent deformation, so that a rejection of the originally flat andsubstantially parallel seal-contact surfaces occurs between which the seal is clamped. This open column, which can be closed by the seal, especially after prolonged use, not by their own resilience.

are also known for angularly movable Glenke certain seals which have a spherically curved contact surface, which cooperates slidably in one of the joint flanges with a complementary shaped counter-surface. For such applications, it is known to wrap sealing body straps which are made of metal wire mesh or -geflecht and mica material chambers.

It is known in the art that can be mica raw split .by treatment with reaction solutions, possibly with additional exposure to higher temperatures, in mica layers. The mica layers or -scheibchen thus obtained are further processed with the addition of binders to films, sheets and molded parts that get after example in the electrical industry for use when it comes to a shape retention members at higher temperatures.

Binderless mica was used in chemically aggressive media for washers or protective layers.

Also known are mica materials, such as vermiculite, which are brought at high temperatures to a highly increased volume (expands). They have been used for secondary purposes, such. As a packaging material or for thermal insulation.

Object of the present invention is to provide a seal of the type mentioned above, which is inexpensive to produce, between flanges can be used with flat seal-contact surfaces and which also ensures a sealing effect, if temperature-induced distortions of the seal-contact surfaces and / or changes in their mutual Location occur.

The invention solves this problem in that the seal is formed of sheet mica material with at least one passage opening that the mica material contains a plurality of stacked flat mica discs, which in turn are formed by a plurality of the thinnest, held together by the natural material bond mica flakes, the mica discs are directed parallel to those intended for the abutment against the flanges outer surfaces with the area of ​​its greatest extent substantially, and that the mica material contains a binder layer which is arranged intermediately in the overlapping areas immediately overlying mica discs, wherein the mica discs and the binder layer of such materials made that the mica material in non-clamped state, a progressive increase in its thickness, measured perpendicular to the largest surface area of ​​the mica discs which, said increase in thickness at about 500⁰ C and used at 800 ° C is at least 100%, relative to the thickness at 20 ° C.

Such a trained seal undergoes at higher temperatures at which significant distortions or changes in distance begin to form the seal-contact surfaces of the flanges, a thickness increase, which opposes a gapping between the outer surfaces of the seal and the aforementioned contact surfaces. It was found that even after this thermally induced thickening of the mica material still retains a considerable inherent elasticity, so that even after a plurality of temperature-load cycles proper sealing effect is given.

Advantageously, there is a binder layer of the mica material between at least edge portions of superposed mica flakes, thereby causing the enlarged seal un-installed state stability receives, during the thermally induced increase in thickness of the seal is improved in the operating state. The binder layer of mica material is advantageously made of synthetic resin, with a flexible silicone resin having functional groups has proven particularly useful. If other types of mica are useful for the purposes of innovation, for example, muscovite, as has been recognized as a particularly convenient material for the mica discs phlogopite mica.

Especially with gaskets, the thickness of which is considerably larger than one millimeter, it is advantageous that the mica material at least one extending substantially parallel to the outer surfaces, each arranged between layers of mica discs support material, for example a thin steel wire mesh containing. As carrier material can also be ceramics, paper, or the like are used.

For practically all applications, it is advantageous that each passage opening has a rim of sheet metal, which engages over the outer surfaces of the mica material with its two annular parts. This enclosure prevents the desired temperature-induced increase in thickness of the mica material very little, but assures its mechanical cohesion and also prevents the medium to be sealed between the individual layers of mica discs or between the minimum thin mica flakes penetrates and attacks the latter chemically and / or mechanically. depen_- depend on the size and the conditions of use of the seal, this may have an opening extending over its entire outer perimeter edging of sheet metal, whose two strip-shaped portions engage over the outer surface of the mica material. Although such an enclosure somewhat hindered the desired temperature-induced increase in thickness of, seal, but gives it a much higher mechanical stability. Instead of facing the outer periphery, a seal, which has further passage openings for receiving tensioning means for the flanges, anletzteren passage openings contain similar enclosures, such as those provided for the passage openings, which are intended for the passage of the medium to be sealed. The hereby given disability of temperature-induced increase in thickness is virtually completely avoided if the further passage openings are surrounded at their partially applied by or remote from the passage openings for the medium to be sealed sites on the outer surfaces of the mica material sheet metal parts which have approximately the shape of half a circular ring , in each case the further passage opening associated metal parts are connected at their outer edges by a metal strip integral with each other, which extends beyond the outer periphery of the seal. The illustrated sheet metal parts keep the outer surfaces of the mica material together only in areas that are irrelevant for the sealing action.

An embodiment of the invention with some variations will be explained with reference to the drawings, in which:<ul><li>. Figure 1 is a plan view of an outer surface of the seal;</li><li>2 shows a cross section through the gasket according to the line II in Fig. 1.</li><li>Fig. 3 according to a greatly enlarged detail of the cross section. Figs. 2 and</li><li>Fig. 4 is a cross-sectional detail in even higher magnification.</li></ul>

The seal is made by punching or by another manufacturing method of a plate of a later explained in more detail mica material 1, the thickness D may be fractions of a millimeter or several millimeters. The seal has in plan view essentially the shape of an equilateral triangle with rounded corners and has a central passage opening 2, as well as three, surrounding this passage openings 3 A, 3 B and 3 C, which 120⁰ are offset from each other, equidistant from the center of the central passage opening 2 and are each located on a corner in the area. This further passage openings 3 A, 3 B 3 C used for receiving tensioning means such as screws that two flanges are clamped together, which are sealed with the seal and directed towards one another with two substantially planar surfaces on the two substantially parallel outer surfaces 4 A, 4 B abut on the seal.

The central passage opening 2 has an existing sheet metal enclosure 5, which with a central part 6, the approximated usually has to tubular shape conforms to the inner circumference of the passage opening. 2 On both sides of this central part 6 he extend integrally formed, annular parts 7, 8 radially outwards. These annular parts 7, 8 are located with pretension on the associated outer surfaces 4 A, 4 B of the gasket to.

Each of the further passage openings 3 A, 3 B 3 C is partially, in each case at the side remote from the central passage opening 2 side, surrounded by a sheet metal part 9, the A at the respective outer face 4, 4 B is applied. Each sheet metal part 9 is in the form of half a circular ring, whose inner radius is slightly larger than the radius of the through opening and whose outer radius is somewhat smaller than the radius of curvature of the corners of the gasket. At each free end of the sheet metal parts 9 a hook-shaped extension 10 is integrally formed, which is approximately at right angles bent and pressed into the mica material.

The same of another passage opening 3 A, 3 B 3 C assigned two sheet metal parts are connected by a metal strip 11 integral with each other, which extends beyond the outer periphery 12 of the seal. In FIG. 1 the illustrated sheet metal part for the further passage opening 3 B is illustrated, although appropriately trained sheet metal parts are also provided on the passage openings 3 A and 3 C.

In a modified embodiment of the seal, instead of the sheet metal parts 9 for the further passage openings 3 A, 3 B 3 C also mounts 13 are provided, which are formed similarly to the enclosure 5 for the central passage opening 2, so that reference can be made to the description thereof. In FIG. 1 is of the three mounts 13 only that for the further passage opening 3 C partially illustrated in phantom.

In another alternative, the seal may have an opening extending over its entire outer periphery 12 enclosure 14, the two strip-like parts 15, the outer surfaces 4 A, 4 B of the mica material comprises 1.

Each of the previously described mounts 5, 13, 14 and sheet-metal parts 9 consists of a metal sheet which is selected with regard to its thickness and its material so that the two flanges compressive force only a relatively small resistance is opposed, ie, the sealing engagement of the flange faces on the outer surfaces 4 A, 4 B precludes any major obstacle.

The mica material 1 contains as an essential component a plurality of flat mica discs 16 which are each directed to the surface of its largest dimension substantially parallel to each other and are randomly located layered overlappingly in a plurality of layers. The mica discs 16 consisting of phlogopite mica, but for special applications a mixture with other types of mica is possible and also exclusively other types of mica, for example muscovite mica, are used. Each mica discs bsteht its part of a plurality of the thinnest mica flakes 17 (Fig. 4), which have already been held together by the natural material bond.

At least in the overlapping portions directly overlying mica discs 16, a binder layer 18 is arranged, which consists of flexible silicone synthetic resin having functional groups. This binder layer 18 is at least one between border regions superposed mica flakes 17th (Fig. 4).

For special purposes and particularly the seals, the thickness D is significantly higher than a millimeter, one or more webs of a support material may be between layers of mica discs 16 parallel to the outer surfaces 4 A, 4 B are disposed, which consists of a temperature-resistant material, for example a thin wire fabric. The substrate 1q can also be formed from a material which is not stable in the temperature range for its use, the seal is provided and has the purpose of sealing to impart better cohesion and a form of resistance to installation.