Seal rings

Seal face material Sealing compounds Sealing rings Sealings Seals... 

Compatibility and Corrosion. Gas turbine fuels must be compatible with the elastomeric materials and metals used in fuel systems. Elastomers are used for O-rings, seals, and hoses as well as pump parts and tank coatings. Polymers tend to swell and to improve their sealing abiUty when in contact with aromatics, but degree of swell is a function of both elastomer-type and aromatic molecular weight. Rubbers can also be attacked by peroxides that form in fuels that are not properly inhibited (see Elastomers, synthetic Rubber, natural). 

Wax ring seal Asphalt seal Support washer Cathode mix manganese dioxide, carbon, electrolyte... 

In operation seal oil pressure is about 30-50 psi over the process gas pressure. The high-pressure oil enters the top and completely fills the seal cavity. A small percentage is forced across the carbon ring seal faces. The rotative speed of the carbon ring can be anywhere between zero and full rotational speed. Oil crossing the seal faces contacts the process gas and therefore contaminated oil. The contaminated oil... 

Be sure all pipe gaskets and ring seals are perfeetly eentered within the flange taees. 

Nitrile (Buna-N) is a rubber compound popular in most household plumbing applications. It s a basic plumbers o-ring seal, and handles most household liquids and chemicals. Because industry pumps so much water, this elastomer may be the single most popular o-ring seeondary seal in the world. Its service range is from -30° F to +250° F (-34° C. to +120 C). 

Let s consider an industrial boiler. You may need at least three of these previous mentioned o-rings just to prevent leaks and drips in a simple hydronie or steam boiler. Raw water comes into the boiler room with pipes, gauges, valves and instrumentation. All these fittings would probably use Nitrile rubber o-ring seals to give long-term leak free service. 

Hard Vacuum Use a balanced o-ring seal for industrial vacuum. For absolute pressure less than 1 kpa (1 kilopascal) use a torsion balanced seal. (Must verify this measurement)... 

Same symptoms as bearing oil whirl except a decrease m lube oil temperature will often eliminate or reduce vibration severity. Seal ring oil whirl Oil ring seal acting as lightly loaded bearing... 

These seals are used extensively in high-speed turbomachinery and have good mechanical reliability. They are not positive sealing. There are two types of noncontacting seals (or clearance seals) labyrinth seals and ring seals. 

Figure 13-31. Restrictive ring seal system with both buffer and eduction cavities.

Probably the most common seal is the restrictive ring type, normally used in the form of carbon rings. This seal controls leakage better than the non-floating labyrinth type, although it wears faster. The carbon ring seal does not tolerate dirt as well as the labyrinth seal. The carbon ring seal and the labyrinth seal may be ported for gas injection, ejection, or a combination of both. Any injection gas should be clean. 

Figure 5-49. Dry carbon ring seal. The carbon rings on this seal are buffered by dry air. Courtesy of Elliott Compant/i...

The barrier seals come in two basic forms. One is a labyrinth design, which is probably the most common. It has the features of a conventional labyrinth discussed earlier. The alternative is the carbon ring seal. The carbon ring is used either as a single ring or, in some cases, it is of a mui-... 

Care must be taken in the assembly of the buffered shaft end seals, particularly in the area of the secondary o-ring seals. A cut or damaged ring can allow more oil to be bypassed than from a damaged main seal. 

Appendix D—Labyrinth and Carbon Ring Seal lueakage Calcidations 539... 

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