DE20200636U1 - sealing ring - Google Patents

Description

P13694 S/vlu *·* ··· *..'..\J.6. January 2002

Applicant: KWO Dichtungstechnik—GmbH Hofgartenstrasse 8 D-83071 Stephanskirchen

Sealing ring

The invention relates to a sealing ring, in particular for use with plastic pipe flanges.

Sealing rings or O-rings are used to seal between pipe flanges, for example pipe flanges made of plastic. Such sealing rings made of expanded PTFE (polytetrafluoroethylene) generally have sintered and/or sealed areas, which are essentially located on the inner diameter of the seal, as well as unsintered or unsealed areas. The purpose of such a seal is to prevent the penetration of a medium (e.g. a gas) into the very porous sealing material made of expanded PTFE and to reduce the leakage flow through the seal.

The invention is based on the object of improving a sealing ring of the type mentioned at the outset in such a way that the surface pressure on the unsealed or unsintered areas can be increased while maintaining the positive properties, whereby even low forces are sufficient to achieve the same surface pressure as known seals.

The sealing ring according to the invention therefore allows the same surface pressure to be achieved with lower forces than the known sealing rings made of expanded PTFE. This is particularly advantageous for flanges with very low strength, for example plastic flanges, since these plastic flanges cannot be subjected to sufficiently high loads when using known seals made of expanded PTFE to ensure a secure seal. According to the invention, a secure seal can be ensured, particularly for flanges with very low strength, by increasing the surface pressure on the unsealed or unsintered areas.

The sealing ring according to the invention has a plurality of sealed and/or sintered regions or surfaces, preferably spaced apart from one another, such that the sealed and/or sintered regions or surfaces are defined in the form of regions lying coaxially with one another.

In a preferred embodiment, the unsealed areas of the sealing ring are also provided with a partially sealed surface of a few µm thickness, thereby reducing leakage into and through these unsealed areas.

In a further embodiment, the unsealed areas are characterized by a multidirectional fiber structure and are partially reversibly compressible. These areas have a high resilience, especially compared to conventional, monodirectionally oriented, expanded polytetrafluoroethylene, which improves the maintenance of the surface pressure.

Preferred embodiments of the sealing ring according to the invention are described below with reference to the drawing to explain further features and advantages.

Show it:

Figure 1 A plan view of the sealing ring according to the invention, and

Figure 2 is an enlarged sectional view taken along the line AA ^&lgr; in Figure 1.

According to the embodiment of Figure 1, the sealing ring according to the invention has annular regions 1, 2, 3, 4 made of sealed, expanded PTFE arranged concentrically to one another, while the sections 6, 7, 8 located between the regions designated 1 to 4 consist of unsealed, expanded PTFE.

In the embodiment shown, the inner diameter is defined by the region 1 and the outer diameter by the region 4. The regions 1 to 4 and the sections 6 to 8 therefore run concentrically to the axis, the distances between the regions 1, 2, 3, 4 through the sections designated 6, 7, 8 preferably being the same size.

Figure 2 shows an enlarged sectional view along the line α-α ^λ in Figure 1.

The unsealed sections 6, 1 ₁ 8 are provided according to a preferred embodiment with a sealed surface or a sealing layer 6a, 6b, 7a, 7b, 8a, 8b,

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which is only a few μm thick and significantly reduces the field strength in and through these sections 6, 7, 8.

In a further embodiment of the sealing ring according to the invention, the unsealed sections 6, 7, 8 are formed by a multidirectional fiber structure which is partially reversibly compressible and therefore has a high resilience, particularly in comparison to monodirectionally oriented expanded PTFE. This high resilience significantly improves the surface pressure in the area of the unsealed sections.

According to a preferred embodiment, the sealed, i.e. surface-sealed sections are produced by sintering or sintering, i.e. subjected to a temperature treatment.

The layer formed by sealing, e.g. by means of liquid, plastic or the like, is designated 6a, 6b, 7a, 7b and 8a, 8b in Fig. 2.

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Claims (6)

1. Sealing ring made of expanded polytetrafluoroethylene, which has sealed and unsealed regions, the sealed regions being formed substantially on the inner diameter, characterized in that a plurality of sealed regions ( 1 , 2 , 3 , 4 ) lying substantially concentrically to one another are provided, which are spaced apart from one another by unsealed sections ( 6 , 7 , 8 ). 2. Sealing ring according to claim 1, characterized in that the unsealed sections ( 6 , 7 , 8 ) each have a sealed surface (6a, 6b, etc.). 3. Sealing ring according to claim 1 or 2, characterized in that the sealed areas ( 1 , 2 , 3 , 4 ) are formed in the manner of concentric circles. 4. Sealing ring according to claim 3, characterized in that the sealed surface or sealing layer (6a, 6b etc.) of the unsealed sections ( 6 , 7 , 8 ) is a few µm thick. 5. Sealing ring according to at least one of the preceding claims, characterized in that the unsealed sections ( 6 , 7 , 8 ) have a multidirectional fiber structure. 6. Sealing ring according to at least one of the preceding claims, characterized in that the sealed regions or sealing layers are formed by sintering their surfaces, while the unsealed regions have unsintered surfaces.