DE7929847U1 - Sealing ring - Google Patents

Description

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PATENTANWÄLTE DIPL.-ΙΜΦ *. A * WEI ^ lIE · blPL.-ΪΝΟ. K. EMPL Deutsche Bank βθ / 22βθΐ BLZ 7OO 70010 BOOO MÖNCHEN θ Beyer. Mypobank I79OO28OOO BLZ 7OOSOO OV Schumannsir. 2 ■ Tel. COHOj 4/15 Poetecheck Mchn. 473 OS.BO3BLZ 7OO 1OÖSO Teleorarnme: Patentwedde - Munchi

October 22, 1979

File: Gm 23 740

company

Feodor Burgmann Dichtungswerk GmbH & Co.

8190 Wolfratshausen }.

Sealing ring

The innovation relates to a sealing ring made of graphite with an essentially rectangular, in particular square, cross-section.

Such known sealing rings are particularly used for sealing rotating shafts or axially moving rods are used as stuffing box seals.

The use of pure graphite offers the advantage of being able to use such sealing rings at very high temperatures without a Hardening or embrittlement occurs and consequently the good long-term

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elasticity is retained. There is an aging of the pure graphite not held.

The disadvantage of such graphite sealing rings is that that electrochemical corrosion can occur on the contact surfaces of the housing and the shaft with the sealing rings, especially if aqueous electrolytes are present at these contact points, such as service water, saline solutions, etc. Due to the high conductivity of graphite, a current can flow between the housing and the shaft to be sealed flow, the metal layer acting as anode being gradually attacked.

Another disadvantage is that graphite layers sticking to the spindles or shafts as a result of abrasion of the sealing rings can train, which very high undesirable drive elements have as a consequence.

Due to the tendency of graphite to be used as a material for sealing rings to flow very easily into the guide gaps of the shafts, the packing wear is increased even further.

The innovation has thus set itself the task, while maintaining the good properties of the graphite sealing rings, these disadvantages with rotating shafts or with rods moving in the axial direction, which are especially important when used in nuclear power plants can have serious consequences. to eliminate, thus an absolute

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Safe operation is guaranteed, especially when made of graphite existing sealing rings with a substantially rectangular or square cross-section the electrical conductivity properties to reduce or completely prevent and at the same time to prevent graphite abrasion.

This object is achieved according to the invention in that a sealing ring of the type mentioned at least on its axial Inner and / or outer surface for insulating electrical

Flow has suitable coating.

By this arrangement an insulation layer between either Sealing ring and shaft or sealing ring and housing wall or both, the formation of a current flow between the contact surfaces reduced or, depending on the choice of material, even prevents and at the same time graphite abrasion and flow of the graphite in the guide or sealing gaps prevented.

In principle, any material that carries an electrical current can be used as a coating or insulation material conducts less than pure graphite or does not conduct at all and meets the various operational requirements without adding to the good properties of the sealing rings made from pure graphite to decrease.

The polytetrafluoroethylene (PTFE) coating is advantageous

manufactured. In addition to excellent insulation, this material also has very good sliding properties and thus contributes to to keep the drive torque on the shaft or spindle low.

In an advantageous further development of the innovation, the coating partially surrounds the sealing ring at least on one its radial end faces.

According to the innovation, the coating is made from a PTFE profile. This corresponds to the dimensions of the graphite ring formed PTFE profile can then in a simple manner with the Sealing ring are assembled.

The PTFE profile is advantageously L-shaped or U-shaped and that on the radial end faces of the sealing ring adjacent legs do not completely cover the end faces.

This formation of the coating causes that under pressure and Temperature influence a flow of the frontal coating in radial direction does not occur.

Several such sealing rings can be combined to form a sealing set and installed in a sealing housing in the area to be sealed and pressed together under pressure. The coating material lying radially on the end faces penetrates here, i.e. the legs of the PTFE profile selected in each case

into the graphite and this way it becomes radial flow the PTFE coating prevents.

The sealing ring is advantageous both on its axial inner side and on its axial outer side of one as Enclosed PTFE profile U-shaped coating.

In the case of a seal set, consisting of a plurality of on a common axis arranged side by side according to the innovation Sealing rings can be made in addition to the sealing rings Graphite on the media and on the atmosphere side a further ring as Chambering be arranged, which e.g. from pure asbestos and / or from pure asbestos impregnated with PTFE. These chamber rings cause that under pressure and temperature flow a possible flow of the on the axial inner surface and / or axial outer surface located PTFE coating is avoided in the axial direction. Such combined chamber rings can also be arranged in front of and behind possibly operational suction rings for the same function.

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The innovation is explained in more detail below with reference to the drawings. i

Show it:

Fig. 1 is a plan view of a sealing ring with a

the coating partially covering the radial sealing surface,

FIG. 2 shows a section along the line II-II in FIG. 1, 10

3 shows a section located in a plane of the diameter

a stuffing box seal set with additional

Locking rings 9 and 10.

The illustrated in Fig. 1, intended for a rotating shaft sealing ring 1 has the shape of a short pipe section with a certain wall thickness and a longitudinal axis 2. \ _: The cross section of the ring is essentially square and the body 3 of the sealing ring is made of pure

Graphite that has been pressed in the direction of the longitudinal axis 2 § . f

The axial inner surface of the sealing ring 1 is marked with a *

The coating 4 made of polytetrafluoroethylene insulates the graphite body 3 of the ring from the shaft to be sealed.

The coating 4, shown in cross section in FIG. 2, has radially outwardly protruding legs 5, which each of the sealing ring 1 on its radial end faces 6 partially cover, these legs 5, as shown in FIG. 1, forming a circular surface 7.

Legs 5 or circular surfaces 7 of the coating 4 are during the installation process of such a sealing ring in a stuffing box seal by the pressing process that takes place presses into the relatively soft graphite material of the body 3, so that a flow of the PTFE material of the coating 4 or the legs 5 is prevented.

In Fig. 3, a packing 8 is illustrated which is composed, for example, of nine sealing rings. Of these nine sealing rings, the seven correspond to the inner ones Sealing rings of the sealing ring 1, the first sealing ring 9 and the last sealing ring 10, on the other hand, have no coating 4 on. These so-called chamber rings consist e.g. of PTFE impregnated pure asbestos material. The arrangement of these chambering rings 9 and 10 prevents the coating 4 under the influence of the pressure prevailing in the installed state in the longitudinal direction between the sealing ring and z. B, wave flow.

As further illustrated in Fig. 3, the legs 5 of the coating 4 in the installed state by the pressure in the off

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Graphite existing body 3 of the sealing rings pressed in, so that a radial outward flow of the PTFE annular surfaces 7 is also prevented.

For gasket sets which have a larger number of coatings 4 provided sealing rings 1 can also, for. B. made of pure asbestos or pure asbestos impregnated with PTFE manufactured sealing rings at a certain distance between them installed if, for example, suction rings are provided for operational reasons.

H / Zi / Koll.

Claims (7)

October 22, 1979 File: Gm 23 740 PROTECTION CLAIMS 1.) Sealing ring made of graphite with an essentially rectangular, especially square cross-section, thereby gekennzei chnet that the sealing ring (1) has at least on its axial inner and / or outer surface a coating (4) suitable for isolating electrical currents.
10 2.) sealing sigsring according to claim 1, characterized marked chnet that the coating is made of polytetrafluoroethylene (PTFE) is made. 3.) Sealing ring according to claim 1, characterized in that it is marked Chnet that the coating (4) the sealing ring (1) at least on one of its radial end faces (6) encompasses. 4.) Sealing ring according to claim 3, characterized in that it is marked chnet that the coating (5) consists of a PTFE profile is made. - II - - II - 5.) Sealing ring according to claim 4, characterized in that g e k e η π-zei chnet that the PTFE profile L-shaped or U-shaped is formed and the radial flow surfaces (6) the leg (5) covering the sealing ring (1) the end faces (6) do not completely cover the radial extent. 6.) Sealing _{ring nr:} ch claim 5, characterized in that the sealing ring (1) is enclosed both on its axial inside and on its axial outside by a U-shaped coating designed as a PTFE profile. 7.) Packing seal, consisting of a plurality of arranged directly next to one another on a common axis Sealing rings according to claims 1 and 2, characterized in that in addition to the sealing rings made of graphite {1) at least as the first and last sealing ring (9 or 10) further sealing rings are arranged are made of pure asbestos and / or as impregnated with PTFE Are made of pure asbestos. H / Col1.