Glossary for Seals, Gaskets, O-Rings, Orings, Rubber.

Includes the terms and definitions for seals, seal, orings, gasket, gaskets, hydraulic seals, hydraulic seal, metric seals, metric seal, o-rings, o-ring, viton, teflon, silicone, rubber, nitrile, ucup, plastic, metric orings, injection molding, oil seals, packings, parts, molding, machining.

This is perhaps the most comprehensive glossary of seal, gasket, packing and molded rubber parts terms available on the internet.

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Oil Resistance - Ability to withstand swelling by a specified oily liquid for specified time and temperature, expressed as percentage swelling or volume increase of specimen. Oil Resistance - as applied to vulcanized elastomer compositions: resistance to change in size and shape and resistance to loss in physical (mechanical) properties due to contacts with or immersion in an oil.

Oil Resistant - Ability of a vulcan- ized rubber to resist the swelling and deteriorating effects of various type of oils.

Oil Seals - Also called grease seals, rotary seals or shaft seals. Made of rubber to seal grease in a housing with a rotating shaft.

Open Cell - A cell not totally enclosed by its walls and hence interconnecting with other cells.

Open Steam Cure - A vulcanization process that takes place under direct steam pressure in an autoclave. It is used where direct pressure molding is not possible. In -the case of vulcanization of sheeting, or coated fabrics, rolls of product are wound onto steel drums (with suitable interleaf) which are placed in the autoclave for cure. Some tubing arid shaped products are placed on pans for extra curing.

Optimum Cure - State of vulcan- ization at which maximum desired property is attained.

Optimum Cure -The physical properties of a rubber compound vulcanized at a given temperature for increasing periods of time undergo continuous change. For example, tensile strength may rise to a maximum, continue on a plateau, and then decline; whereas breaking elongation may continuously decrease. Therefore it is impossible to choose any one time of cure at which every property will be at its optimum, hence optimum cure is a compromise and may be considered as that time required to obtain the combination of properties most desirable for the article under consideration.

Opti-Seal - A special seal ring to provide optimum sealing.

O-rings - O-ring seals are circular rings of various cross-sectional configurations installed in a gland to close off a passageway and prevent escape or loss of a fluid or gas. An oring is specified by three of its features: its dimensions, material, and hardness. Material and hardness specify the elastomeric compound and Shore A (durometer) hardness of the compound that is used to manufacture the o-ring. An O-ring's dimensions are described by stating its inside diameter (I.D.) and its cross-section. Designing for o-rings depends on three major and interrelated variables: the operating conditions or environment the seal will experience, the gland geometry into which the seal will be installed and the three variables account for the fact that there are so many different types of seals and applications.

Overcure - A state of excessive vulcanization resulting from overstepping the optimum cure, i.e., vulcanizing longer than necessary to attain full development of physical strength. Manifested by softness or brittleness, and impaired age resisting quality of the vulcanizate.

Oxidation - Active oxygen organic materials. This is called oxidation. Rate of degradation will increase with rising temperatures.

Ozone - An allotropic from oxygen, (03), produced by (he action of electrical discharges in air. It is a gas with a characteristic odor, and Is a powerful oxidizing agent. Rubber compounds in a stretched condition are susceptible to the deteriorating action of ozone in the atmosphere, which results in a cracked condition.

Ozone cracking - The surface cracks, checks, or crazing caused by exposure to an atmosphere contain- ing ozone.

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