O RING

Physically, silicone o-rings are based on silicon, an element derived from quartz. To create this class of synthetic elastomers, pendant organic groups such as methyl, phenyl and vinyl are attached to silicon atoms. Different additions of side chains can achieve significant variations in properties. Silicone o-rings have excellent heat, ozone and corona resistance and have good dielectric stability and resistance to many oils, chemicals and solvents. Silicone o-rings maintain the best flexible property at low temperatures but have low tensile strength and low wear and tear resistance.

Silicone o-rings may also come in a metal detectable variation, while retaining the same qualities as the general silicone o-ring compound. O-Ring and Seal supplies silicone o-rings that are compliant with Food Grade standards, and are suitable for use in food and beverage production lines, as well as medical and pharmaceutical manufacturing.

Cure System: Peroxide-Cured:

Standard silicone o-ring compounds are usually peroxide-cured. Platinum-cured compounds offer better flexible properties and very low volatile matter. Platinum-cured silicone o-rings usually are applied in medical systems or other required low volatile matter. However, they need to be produced in a clean room and with a higher cost of platinum catalyzer, making them more expensive than peroxide-cured ones.

Performs Well In:

• Engine and transmission oil (mineral oils)
• Diluted salt solution
• Moderate water
• Dry heat
• Ozone and weather resistance

Doesn't Perform Well In:

• Concentrated acids and alkalis
• Steam over 120ºC (248ºF)
• Petroleum oils and fuels
• Ketones

Quad Rings (also known as X-Rings) have a sealing function doubling that of an o-ring, and can be used in a numerous static and dynamic sealing applications.

Compared to a standard o-ring, the four-lobed Quad Ring profile maintains twice the sealing surface. The double-seal action requires less squeeze to maintain an effective seal function. With reduction in squeeze, this yields lower friction and prolonged seal life.

To prevent leakage, which typically results from a parting line’s irregular surface on an o-ring, the parting lines on an X-Ring are between the lobes, and away from the sealing surface.

X-Rings are also made to surpass the performance of a standard o-ring in rotary seal applications. The four-lobed design produces a more secure seal to counteract spiral twisting. This allows the use of a narrower groove width than a standard o-ring groove, but can also be used in a standard o-ring groove.

Advantages of X-Rings vs. O-Rings

• Prevents contorting in the groove. The seal is not apt to roll in the groove with corresponding movement.
• Low friction. It requires less radial squeeze compared to a standard o-ring.
• Less wear due to low friction, thus providing a longer service life.
• Excellent sealing efficiency with its special profile.
• Improved startup with the lubricant reservoir formed between the sealing lips.

HNBR O-Ring Material Description:

Hydrogenated Nitrile (HNBR) o-rings, also known as Highly Saturated Nitrile (HSN), are made of a synthetic polymer that is obtained by saturating the double bonds in nitrile=s butadiene segments with hydrogen. This special hydrogenation process reduces many double bonds in main chains of NBR polymers. This process results in the superior heat, ozone, chemical resistance and mechanical characteristics of HNBR over standard Nitrile. HNBR o-rings are available in 60 durometer, 70 durometer, and 80 durometer.

HNBR o-rings are preferable for use with petroleum-based oils and fuels, aliphatic hydrocarbons, vegetable oils, silicone oils and greases, ethylene glycol, water and steam (up to 300ºF), and diluted acids, bases, and salt solutions. HNBR o-rings are not preferable for use with chlorinated hydrocarbons, ketones, ethers, esters, and strong acids.

Performs Well In:

• Petroleum based oils and fuels
• Aliphatic hydrocarbons
• Vegetable oils
• Silicone oils and greases
• Ethylene glycol
• Dilute acids, bases, and salt solutions to moderate temperatures
• Water and steam to 150ºC (300ºF)

Doesn't Perform Well In:

• Chlorinated hydrocarbons
• Ketones
• Ethers
• Esters
• Strong acids

Polyurethane O-Rings Description:

Polyurethane rubber is a thermoplastic elastomer formed by reacting a polyol with a diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. Polyurethane rubber is widely used due to its high strength, and excellent tear and abrasion resistance. Polyurethane also provides excellent permeation resistance.

Polyurethane O-Rings Temperature Range:

The temperature range 250 F° to -30 F° are approximations for dry air service only and should not be used to determine design specifications or end-use temperature limits. Actual temperature range of a compound in an end-use application is highly dependent on part type, hardware configuration, applied forces, chemical media, pressure and thermal cycling effects, and other factors. The most practical way of determining an end-use temperature range is testing in the actual application conditions.

Polyurethane Rubber O-Rings Features:

• Good hydraulic oil and gasoline resistance
• Resistant to pure aliphatic hydrocarbons (propane, butane, fuel)
• Resistance to mineral and silicone oils and greases
• Resistant to water, oxygen, ozone and aging
• Excellent tear and abrasion resistance
• Available in multiple types and compounds to meet performance and cost requirements

Polyurethane Rubber O-Rings Limitations:

• Not compatible with acids, ketones, esters, ethers, alcohols, glycols
• Hot water, steam, alkalis and amines.

There is often confusion around the terms FDA Grade, FDA Compliant, FDA Certified, etc. As a general policy, the Food and Drug Administration does not “certify” o-rings. Rather, they publish guidelines to specify ingredients that can be used in rubber parts which may come in contact with food. It is then the responsibility of the manufacturer to certify that the parts they provide are “FDA Compliant”.

What does it mean for a rubber o-ring to be FDA-compliant?

FDA-compliant means passing the Code of Federal Regulations, which covers:

• Dry Foods: Must meet formulation and curation criteria under conditions of good manufacturing practice as appropriate for repeated use.
• Liquids: Must meet extraction criteria (not exceeding 20mg/sq inch in distilled water).
• Fatty Foods: Must meet additional extraction criteria (not exceeding 175mg/sq inch in n-hexane).

Here are a few of our standard FDA-compliant o-ring compounds:

FDA-Grade O-Rings

• Material: Silicone Color:      Red
• Material:    Nitrile (Buna-N) Color: Black
• Material:    Viton Color:        Black
• Material:    EPDM Color:       Black

Nitrile rubber (NBR) o-rings, also known as Buna-N, are one of the most commonly used sealing elastomers due to resistance to petroleum-based fuels and lubricants and its relatively low price. Nitrile elastomers are copolymers of acrylonitrile and butadiene. There are a number of common variations of nitrile compounds. Nitrile o-rings may also come in a metal detectable variation, while retaining the same qualities as the general Nitrile o-ring compound.

Performs Well In:

• Petroleum based oils and fuels
• Aliphatic hydrocarbons
• Vegetable oils
• Silicone oils and greases
• Ethylene glycol
• Dilute acids
• Water up to 100ºC (212ºF)

Doesn't Perform Well In:

• Aromatic hydrocarbons
• Automotive brake fluid
• Chlorinated hydrocarbons
• Ketones
• Ethers
• Esters
• Phosphate ester hydraulic fluids
• Strong acids
• Ozone, weathering, and sunlight

A Flat Ring is a sealing device made in the form of a torus (round top view), with a square-shaped cross-section.

Other names for Flat Rings are Washer Rings and Square Rings.

The primary reason for using a Flat Ring in a sealing application is that they perform the sealing function in a superior manner – and at a cost lower than any other comparable sealing device. For existing applications, there is no need to change the design or procedures. Flat Rings fit in o-ring grooves and are interchangeable size for size.

Flat rings are available in a variety of rubber and plastic materials such as Buna, Viton, EPDM, PTFE,PU etc. In most static applications, a Flat Ring will serve as a direct replacement for an o-ring and generally will perform a high-pressure sealing function as well as or better than an o-ring.

Features of Flat O Rings:

• Interchangeable with o-rings size for size.
• Uses the same groove as an o-ring
• Can be used for radial seals
• Material is homogenous with no joints or laminations
• Edges accurately formed
• Extreme close tolerances held on cross-section, ID, and OD
• Controlled surface smoothness, hardness, elasticity, toxicity, texture
• The modern, economical option for static applications
• Available in many compounds

Performs Well In:

• Alcohols
• Automotive brake fluid
• Ketones
• Dilute acids and alkalis
• Silicone oils and greases
• Steam up to 204.4ºC (400ºF)
• Water
• Phosphate ester based hydraulic fluids
• Ozone, aging, and weathering

Doesn't Perform Well In:

• Aliphatic and aromatic hydrocarbons
• Di-ester based lubricants
• Halogenated solvents
• Petroleum based oils and greases

Polytetrafluoroethylene (PTFE) is a high molecular weight polymer, one of the most versatile plastic materials known and useful for a large range of products for applications excluded to other materials. PTFE o-rings are known for high heat resistance, high resistance to chemical agents and solvents, anti-adhesiveness, dielectric properties, low friction coefficient, and non-toxicity.

The tensile and compressive properties are to a large degree influenced by the working processes and the polymer used. PTFE, however, can be used continuously at temperatures up to 260°C (500°F), while possessing still a certain compressive plasticity at temperatures near to the absolute zero.

PTFE O-Ring Temperature Range:

Standard Low Temp: -200°C (-328°F)
Standard High Temp: 260°C (500°F)

Neoprene is a multi-purposed elastomer which yields a balanced combination of properties. Neoprene o-rings are typically seen in the refrigeration sector, as they demonstrate remarkable resistance to chemicals such as ammonia and a variety of coolants.

Neoprene o-rings also perform well in contact with oils and many chemicals and has good resistance to sun, ozone and weather. The material displays outstanding toughness and good resistance to fire.

Neoprene o-rings typically are black in color, with a shelf life of 15 years.

Performs Well In:

• Refrigerants
• Ammonia
• Water
• Silicone grease and oils
• High aniline point mineral oil

• Aromatic hydrocarbons
• Ketones
• Esters
• Ethers
• Strong oxidizing acids
• Chlorinated hydrocarbons

NBR / Buna Nitrile O-Ring Material Description:

Nitrile rubber (NBR) o-rings, also known as Buna-N, are one of the most commonly used sealing elastomers due to resistance to petroleum-based fuels and lubricants and its relatively low price. Nitrile elastomers are copolymers of acrylonitrile and butadiene. There are a number of common variations of nitrile compounds. Nitrile o-rings may also come in a metal detectable variation, while retaining the same qualities as the general Nitrile o-ring compound.

Performs Well In:

• Petroleum based oils and fuels
• Aliphatic hydrocarbons
• Vegetable oils
• Silicone oils and greases
• Ethylene glycol
• Dilute acids
• Water up to 100ºC (212ºF)

Doesn't Perform Well In:

• Aromatic hydrocarbons
• Automotive brake fluid
• Chlorinated hydrocarbons
• Ketones
• Ethers
• Esters
• Phosphate ester hydraulic fluids
• Strong acids
• Ozone, weathering, and sunlight

Viton Material Description

Viton is also known as FKM. FKM is a well-known high-performance rubber that has excellent resistance to high temperature, ozone, weather, oxygen, mineral oil, fuels, hydraulic fluids, aromatics and many organic solvents and chemicals.

Viton variations include: Viton A, Viton B, Viton F, Viton GLT, Viton GFLT, Viton Extreme (a.k.a. Viton ETP)

Standard FKM o-ring compounds are bisphenol-cured. FKM o-ring compounds with peroxide-cured possess better acid solution resistance than the bisphenol-cured and can replace litharge-cured applied in acid solutions. In some lubricants, adding a few organic amide or amine, or choosing peroxide-cured system Viton o-rings will be better than bisphenol curing systems.

Standard Low Temp: -26°C (-15°F)
Standard High Temp: 232°C (450°F)