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Parker O-ring Division
Parker O-ring Division
The High Performance
Leader
Material Technolog
y
Material Technolog
y
The Chemistry of Elastomers
Rubber TechnologyRubber Technology
“Rubber” compounds are resilient (elastic) materials made from one or more cross-linked base polymers, reinforcing agents, processing aids, and performance-enhancing additives. Compounds are tweaked for performance variations by adding other ingredients to the base polymer.
Polymers – Basic InformationPolymers – Basic Information
Base polymer determines chemical resistance, rough temperature limits, and rebound resilience. Also provides “baseline” for abrasion resistance, compression set resistance, permeability.
Polymer chains must be “glued” together (cross-linked) to achieve resilience and elasticity. Typical curing systems are Sulfur, Organic Peroxides, and Bisphenol.
Compounding - FillersCompounding - Fillers
Fillers are reinforcing agents that add mechanical strength and resistance to abrasion, permeation, and compression set Carbon black: standard for black
compounds Silica: standard for non-black compounds
Pasticizers are oils and/or polymers used to lower the low temp limit of Nitrile and make the material flow better
O-ring materials used at Kimray
O-ring materials used at Kimray
Nitrile (NBR) BunaHydrogenated
Nitrile (HNBR) HSNEthylene-Propylene
(EPR, EP, EPDM)Polyurethane (AU,
EU)
Fluorocarbon (FKM) Viton®
Tetrafluoroethylene-Propylene (TFE/P) Aflas®
Perfluoroelastomer (FFKM) Kalrez®, Chemraz®, Parofluor®
Standard MaterialsStandard Materials
Fluorocarbon (FKM) VITON®
-15° F to + 400° F V1164-75Fluorocarbon (FKM) VITON®
-15° F to + 400° F V1164-75
Recommended For Petroleum oils Silicone fluids Acids (Black ONLY) Aromatic solvents Halogenated
hydrocarbons Air
Not Recommended For Ketones Steam and hot water Amines Low temperature Automotive brake
fluid Aircraft brake fluid
Nitrile (NBR) Buna -40° F to 250° F N0674-70
Nitrile (NBR) Buna -40° F to 250° F N0674-70 Recommended for:
Aliphatic hydrocarbons (propane, butane, petroleum oil, mineral oil and grease, diesel fuel, fuel oils) vegetable and mineral oils and greases.
Dilute acids, alkali and salt solutions at low temperatures.
Water (special compounds up to 100°C) (212°F).
Not recommended for: Fuels of high aromatic
content (for flex fuels a special compound must be used).
Aromatic hydrocarbons (benzene).
Chlorinated hydrocarbons (trichlorethylene).
Polar solvents (ketone, acetone, acetic acid, ethyleneester).
Strong acids. Brake fluid with glycol
base. Ozone, weather and
atmospheric aging.
Hydrogenated Nitriles (HSN, HNBR) -25° F to 300/325° F
Hydrogenated Nitriles (HSN, HNBR) -25° F to 300/325° F Recommended for:
Well service Improved methanol
and sour gas resistance over nitrile
High temperature resistance relative to Nitrile
Petroleum oils Water/Steam Dilute acids and bases Aliphatic hydrocarbons Ozone
Not recommended for: Polar solvents
(methanol and ketones)
Strong acids Fuels Chlorinated
hydrocarbons Acetone Aldehydes
N4007-95, KB163-90, N1231-80, N1173-70
SpecialMaterialsSpecial
Materials
Ethylene Propylene
(EPDM, EP, EPR)
Ethylene Propylene
(EPDM, EP, EPR)
Ethylene –Propylene (EPDM, EPR) -60° F to + 250° E0962-90
Ethylene –Propylene (EPDM, EPR) -60° F to + 250° E0962-90Recommended for
Geothermal Steam service
(500°F) Explosive
decompression Steam/oil mixtures
of less than 10% petroleum fluid
Not Recommended for Mineral oil
productsE0962-90 is unique in that is can withstand continous steam applications at 500°F
Highly Saturated
Nitrile (HSN, HNBR)
Highly Saturated
Nitrile (HSN, HNBR)
Low Temperature HNBR -58° F to + 300° F KA183-85
Low Temperature HNBR -58° F to + 300° F KA183-85
Wide temperature range: Excellent abrasion resistance Excellent wear resistance Good extrusion resistance
Extensive testing profile for EOG-specific requirements which include testing in: Methanol Oil Marston Bentley’s oceanic fluids Kerosene Baroid’s Petrofree drilling fluid
Fluorocarbon (FKM)
Fluorocarbon (FKM)
Low Temp Fluorocarbon(FKM)-55° F to + 400° F V1289-75
Low Temp Fluorocarbon(FKM)-55° F to + 400° F V1289-75
Compared to GLT FKM: Better low temperature
rating than GLT FKM Lower volume swell than
than GLT FKM Compared to GFLT FKM:
Better low temperature rating than GFLT FKM
Better compression set than GFLT FKM
Compared to standard FKM Better low temperature
rating than standard FKM Lower volume swell than
standard FKM Compared to low
temperature Nitrile Better compression set
than Nitrile Lower swell than Nitrile No dry-out shrinkage Better high temperature
rating than Nitrile
V1289-75 has significant advantages compared
with other elastomeric seal materials:
Sour Gas Service FKM+10° F to + 400° F VP104-85
Sour Gas Service FKM+10° F to + 400° F VP104-85VP104-85 has significant advantages for the Energy, Oil and Gas industry compared
with other elastomeric seal
materials Compared to standard A-
type FKM Better explosive decompression
resistance in sour gas Better amine resistance Better base resistance Better methanol resistance Better steam / hot water
resistance Compared to FFKM
Better explosive decompression resistance in sour gas
Lower cost
Compared to HNBR Better ED resistance Better steam/hot water
resistance Better acid/base
resistance Better high temperature
performance Compared to high-
temperature HNBR Better explosive
decompression resistance in sour gas
Better steam/hot water resistance
Better acid/base resistance
Better high temperature performance
ETP Fluorocarbon (FKM)-15° F to + 400° F V1260-75
ETP Fluorocarbon (FKM)-15° F to + 400° F V1260-75
Increased Chemical Compatibility Practically everything Polar and Aromatic
solvents
Not Recommended For Refrigerant gases Low cost
applications Low temperatures
Polymer trade name is Viton® Extreme – similar performance to Hifluor®, but usually a lot less expensive.
Explossive Decompression Resistant 15°F to +400°FFKM V1238-95
Explossive Decompression Resistant 15°F to +400°FFKM V1238-95
95 Shore A Durometer Fluorocarbon. Developed for maximum extrusion
resistance, good compression set resistance.
ED ResistantApplications: High temperature, high-
pressure H2S.
FFKM HIFLUOR ®
TFE/P
FFKM HIFLUOR ®
TFE/P
Specialty Compounds
Parofluor ULTRA(FFKM) +5° F to + 600° F
Parofluor ULTRA(FFKM) +5° F to + 600° F
Recommended For Down hole (sour gas) Drilling mud Amine-based fluids Steam and other
aggressive fluids High temperature
applications
Not Recommended For Refrigerant gases Low cost
applications Low temperatures
FF200-75 FF500-75 FF202-90
Competes directly with Kalrez ® and Chemraz. ® The best of the best.
Chemical Family FF500-75 FF200-75 Kalrez® 4079
Organic Acids 1 1 1
Inorganic Acids 1 1 1
Bases 1 2 3
Amines 1 3 4
Steam/ Hot Water 1 2 3
Ketones 1 1 1
Aldehydes 1 2 4
FFKMChemical Resistance Properties
FFKMChemical Resistance Properties
Hifluor ® (FKM) -15° F to + 400° F
Hifluor ® (FKM) -15° F to + 400° F
Recommended For Down hole (sour gas) Drilling mud Amine-based fluids Steam and other
aggressive fluids
Not Recommended For Refrigerant gases Low cost applications Low temperatures
V3819-75 V8534-90
Similar chemical properties as Parofluor but about 20% less expensive.
Aflas® (TFE/P) +15° F to + 450° F
Aflas® (TFE/P) +15° F to + 450° F
Recommended For Petroleum oils Alcohols Silicone fluids Sour gas Amines Air Steam / hot water
Not Recommended For Low temperature Gasoline
V1041-80 VP101-80 VP103-90
Poor compression set – primarily used in chemical plants.
ExplosiveDecompressi
onMaterials
ExplosiveDecompressi
onMaterials
Explosive Decompression Resistant CompoundsExplosive Decompression Resistant Compounds
N1231-80 (HNBR)E0962-90 (EPDM)- VP103-90 (Aflas®)-V1238-95 (FKM, Viton®)-V8534-90 (HiFluor®)-V8588-90 (Parofluor®, FFKM, Kalrez®)-FF202-90 (Parofluor Ultra®, FFKM,
Kalrez®)-
Failure ModesFailure Modes
Maximizing life through failure
diagnosis
Common reasons for O-Ring failure(Often an O-Ring fails from a combination of problems)
Common reasons for O-Ring failure(Often an O-Ring fails from a combination of problems)
Abrasion Chemical attack Compression set Cracks in Nitrile rubber Exceeding material temperature
limits Explosive Decompression Extrusion and/or nibbling Installation Damage Overfill Spiral failure
AbrasionAbrasion
Looks like the seal is sanded off or flattened on one side of the o-ring.
Causes: Poor surface finish O-Ring passes over ports Use of non abrasion resistant material Excessive swell and softening No lubrication
AbrasionAbrasion
Solutions: Check finish and smooth if necessary Use a lubricant or internally lubricated
material Use a material that resists wear Use a lower swell material
Chemical AttackChemical Attack
The seal swells a lot, shrinks, loses physical properties. Excessive swell, brittleness, and
dramatic loss in physical properties. Find a compatible base polymer.
Shrinkage: the fluid is probably extracting something from the rubber.
Chemical AttackChemical Attack
Chemical AttackChemical Attack
Solutions: Use material compatible with all
fluids. Determine percentage of all fluids in the stream.
Find a compatible base polymer. Determine compound by chemical analysis and reviewing MSDS.
Change compounds (changing the base polymer isn’t always required.)
Compression SetCompression Set
O-Ring Conforms to shape of groove
Looks like the seal has been flattened or deformed.
Causes: Happens whenever rubber is
compressed -- is accelerated by:o excessive or insufficient
squeezeo high temperatureso Chemical attack due to
incompatible fluids.
Compression Set = amount of loss / initial deformation
Compression Set = (HI – HR)/ (HI – HC)
Compression Set = (.100 - .090) / (.100 - .075)Compression Set = (.010) / (.025 ) = .40Compression Set = 40%
HIHC HR
Compression SetCompression Set
Compression SetCompression Set
Compression SetCompression Set
Solutions: Evaluate gland dimensions
ocheck for proper squeezeoconsider tolerancesoconsider ID stretch and cross section reduction
Evaluate materialocheck for compatibility with fluids and
temperatureouse set resistant compound
Evenly spaced radial cracking around the circumference of the O-Ring (typically Nitrile) -- especially where it’s stretched.
Causes: Ozone, UV light, Fluorescent light,
Electric motors. There is ozone in the air around us, and this can be enough to destroy an O-Ring.
Cracks in Nitrile RubberCracks in Nitrile Rubber
Cracks in Nitrile RubberCracks in Nitrile Rubber
Cracks in Nitrile RubberCracks in Nitrile Rubber
Solutions: Coat o-rings with a silicone or
petroleum lubricant Choose a base polymer that is
naturally resistant to ozone
Cracks in Nitrile RubberCracks in Nitrile Rubber
Low Temperature FailureLow Temperature Failure
Seal leaks at low temperatures only. As seal materials cool to within 15oF of their
minimum operating temperature, they lose resilience. Any movement may allow leakage of low viscosity liquids and gases. Low temperature changes are not permanent and do not damage the seal.
Use a seal material with improved low temperature performance.
High Temperature FailureHigh Temperature Failure
Rubber “melts” or becomes brittle. Every rubber polymer has a temperature
above which it begins to break down. Thermal degradation is permanent and irreversible.
Use a seal material with improved high temperature performance or cool the seal gland area.
Explosive DecompressionExplosive Decompression
Internal or external cracks, ruptures, blisters.
Causes Gasses permeate material and
when system is rapidly decompressed, gas quickly escapes leaving ruptures
Explosive DecompressionExplosive Decompression
Explosive DecompressionExplosive Decompression
Solutions: Slice cross section at blister or rupture
and look for internal fissure to verify explosive decompression is cause
Determine application pressure and decompression rate
Slow decompression rate Use explosive decompression resistant
material Use a more explosive decompression
resistant material such as V1238-95.
Extrusion and NibblingExtrusion and Nibbling
Looks like one side of the seal is chewed off.
Is caused by high pressure “pushing” the O-Ring into a gap between the metal surfaces.
Causes. High pressure Excessive clearance Excessive swelling and softening
Extrusion and NibblingExtrusion and Nibbling
Extrusion and NibblingExtrusion and Nibbling
Extrusion and NibblingExtrusion and Nibbling
Extrusion and NibblingExtrusion and Nibbling
Extrusion and NibblingExtrusion and Nibbling
Solutions Evaluate gland design
oUse InPHorm or extrusion chart to determine pressure rating
o If gland can be widened, use backup ring
Evaluate materialoUse higher pressure materialoUse material compatible with the
environmentoUse extrusion resistant compound
if necessary
Installation DamageInstallation Damage
Sheared, torn, nicked cut appearance
Causes: sliding over threads insufficient chamfer improper size no lubrication
Installation DamageInstallation Damage
Installation DamageInstallation Damage
Solutions: cover threads during installation use lubrication chamfer and smooth edges use correct size
OverfillOverfill
Appears similar to extrusion, but nibbling is on both sides, or O-Ring takes set with visible ridge over groove edge.
Causes Insufficient void space in groove Excessive swell in system fluids Improper size O-Ring
OverfillOverfill
Solutions: Use proper groove width Use lower swell material Use smaller cross section if squeeze
is not reduced below recommended minimum
Spiral FailureSpiral Failure
Looks like a split wrapping around the ring.
Causes: Happens when the seal on a piston or
rod “grips” instead of slides in one spot (common with long, slow strokes).
Can happen on static seals with pressure cycling.
ID to CS aspect ratio, reciprocating Installation damage Soft material No lubrication
Spiral FailureSpiral Failure
Spiral FailureSpiral Failure Solutions:
Can be prevented by using a smoother surface, lubricating uniformly, using a stiffer rubber compound, or using an engineered seal.
Use proper cross section for inside diameter to provide stability in groove for reciprocating seal
Use a lubricant or internally lubricated material
evaluate surface finish, chamfer, sharp edges
Use different cross section shape to provide stability in groove
QuestionsQuestions