O-Ring
O-rings are annular sealing elements. The name derives from the round ( O-shaped ) cross-section of the ring.
O -rings are standardized according to ISO 3601, this standard is valid in Germany as DIN ISO 3601. By August 2010 in Germany the DIN standard DIN 3771 was valid. In the GDR was round ring (TGL 6365) ( colloquially zero -ring) is the common term for this sealing element.
Production
Due to the relatively simple form of O-rings are easily produced industrially. Preferably, place the molding ( injection molding) application in smaller numbers, or extremely expensive rubbers are manufactured by means of the O-rings molding ( compression molding ). Depending on the application and requirements ( such as resistance to oils, fats, acids, heat, vacuum tightness ) are used different materials such as various types of rubber, perfluoro ( FFPM or FFPM ), polyethylene ( PE) or polytetrafluoroethylene (PTFE). Rarely, the metal is used (eg, reactor seals in NPP or hot runner systems).
Operation
Due to its circular cross-section O-ring seal may axially and / or radially. By the compression of the rubber body during installation ( in both the radial and / or axial direction) comes about, the initial tightness. The sealing pressure resulting from the superposition of the pre-compression ( through the installation) and the sealed system pressure. In the sealing joint, therefore, there is always a higher order, the pre-compression sealing pressure than the pressure to be sealed. Therefore, very high pressures can be sealed.
A dynamic use, as it occurs for example in single-lever mixers, makes sense only at a low stress. This is mainly due to the speed at which, for example, a plunger is moved, and the system pressure. Even with slow-spinning spindles and shafts can be used o-rings.
Application
The type of seal O-ring has large, diverse use potential, including in the automotive and mechanical engineering, the sealing element is used. Practically in every area of the industry they are found, such as O -rings are also available in any standard household single-lever mixer fitted ( faucet ). Most of the O- ring is present in static seals, while the radially - static as well as the axial static seal can be distinguished. To the former include the use on cylinders or tubes, the axial in the flanges, plates and fasteners.
In the piercing scene O -rings are often used to fix jewelry larger diameter for dilated piercings.
Standard dimensions
O -rings with " inner diameter × thickness cord " dimensioned, for example, 10 × 1.0 mm.
O -rings are usually manufactured in different standard sizes. This line strengths (diameter of the circular cross-section) of from 0.35 mm for very delicate applications up to 40 mm or more are possible. One of the smallest known O -rings used in the Swiss watch production and has the dimensions of 0.70 × 0.20 mm. The inside diameter, depending on the use to the meter range range (eg sealing of sewer pipes or tube structures). One of the biggest O- rings include seals for space telescopes or nuclear reactors with inner diameters of over 10 meters.
DIN 3771-1:1984-12 calls for rings with an internal diameter of 1.8 mm to 17 mm, a typical cord thickness of 1.8 mm. The inner diameters are staggered depending on the application, eg 6.0 / 6.3 / 6.7 / 6.9 / 7.1 / 7.5 mm. In the range of 14 to 38.7 mm, the typical line thickness is 2.65 mm, in the range of 18 to 200 mm, it is 3.55 mm, etc., up to 670 x 7 mm. Rings with eg 14 /15/ 17 mm, there is according to the standard in the line strengths of 1.8 or 2.65 mm.