Elastomeric Seal

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Proper Elastomeric Seal Proper Elastomeric Seal Selection for Process Selection for Process

Analyzer Sample SystemsAnalyzer Sample SystemsSteve Doe

Parker Hannifin Corporation

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Topics Elastomeric Seals & NeSSI Compounding O-Ring Design Chemical Compatibility

Proper Elastomeric Seal Selection for Proper Elastomeric Seal Selection for Process Analyzer Sample SystemsProcess Analyzer Sample Systems

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No Matter Which System...

Elastomeric Seals & NeSSIElastomeric Seals & NeSSI

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…Elastomeric Seals Are In The Picture!

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Seal Do’s & Don’tsSeal Do’s & Don’ts

Do: “Capture”Do: “Capture”

IntraFlow Pressure Connector

R-Max Surface Mount Interface (not SP76)

SP76 Interface

Don’t: Expose Seal Don’t: Expose Seal ID to Fluid FlowID to Fluid Flow

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Metal and plastic retained elastomeric composite sealsPolymeric and plastic sealsHomogeneous and inserted elastomeric shapesElastomeric O-RingsRubber and plastic boots/bellowsExtruded and precision-cut and fabricated elastomeric sealsThermoplastic engineered sealsEMI shielding and thermal management products

Seal Group ProductsSeal Group Products

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Elastomeric Seals & NeSSIElastomeric Seals & NeSSIAlternatives:Alternatives:

• Special Geometry O-Ring SealSpecial Geometry O-Ring Seal• Mold Onto Stainless WaferMold Onto Stainless Wafer

• Stick With 2-007 in Couterbore (what we have)Stick With 2-007 in Couterbore (what we have)

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“… “… designs and designs and manufactures manufactures engineered engineered elastomeric o-ring elastomeric o-ring sealsseals.”.”

Parker O-Ring DivisionParker O-Ring Division

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Extrusion & NibblingExtrusion & Nibbling

Failure ModesFailure Modes

Spiral FailureSpiral Failure

Explosive Explosive DecompressionDecompression

CuttingCutting

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The seal swells, shrinks, loses The seal swells, shrinks, loses physical properties, or gets physical properties, or gets brittle.brittle. Excessive swell, brittleness,

and dramatic loss in physical properties

Shrinkage: the fluid is extracting something from the rubber (changing the base polymer usually isn’t required.)

Failure ModesFailure Modes

Chemical AttackChemical Attack

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Butyl (IIR)Butyl (IIR)

Neoprene (CR)Neoprene (CR)

Ethylene-Propylene (EPR, Ethylene-Propylene (EPR, EPDM) EPDM)

Fluorosilicone (FVMQ) Fluorosilicone (FVMQ)

Nitrile (NBR)Nitrile (NBR)

Polyacrylate (ACM)Polyacrylate (ACM)

Hydrogenated Nitrile (HNBR)Hydrogenated Nitrile (HNBR)

Polyurethane (AU, EU)Polyurethane (AU, EU)

Silicone (VMQ) Silicone (VMQ)

Fluorocarbon (FKM)Fluorocarbon (FKM)

Tetrafluoroethylene-Tetrafluoroethylene-Propylene (TFE/P)Propylene (TFE/P)

Perfluoroelastomer (FFKM)Perfluoroelastomer (FFKM)

O-Ring PolymersO-Ring Polymers

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% Volume Swell in MEK

050

100150200250300350

65 66 67 68 69 70 71 72 73 74 75

% Fluorine in Polymer

% V

ol. C

hg.

GLTV0835-75

AV1164-75 B

V0834-75

GFV0965-80

GFLTV1163-75

ExtremeV1260-75

HifluorV3819-75

ParofluorTM

V8545-75

NEWV1263-75

Performance of FluorocarbonPerformance of Fluorocarbon

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Performance of FluorocarbonPerformance of Fluorocarbon

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Parofluor is a true Perfluoroelastomer polymer

The Parofluor base polymer is a composition of 3 or more monomers

A & B represent different fillers and curatives used to enhancephysical & thermal properties

Parofluor™ UltraParofluor™ Ultra

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to 550to 6005 to 4465 to 6085 to 525Temperature Range, F

3525251619Compression Set, 70

hrs at 400F, % (2-214 O-rings)

--+5+5+6TR – 10, F

125150140124135Elongation, %

18001050115011311262Modulus at 100%, psi

27002450175017402045Tensile Strength, psi

8075757575Durometer, Shore A

Kalrez 1050

Kalrez 4079

Chemraz 505 FF200-75 FF500-75Physical Properties


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Base polymer determines chemical resistance, rough Base polymer determines chemical resistance, rough temperature limits, and rebound resiliencetemperature limits, and rebound resilience In some materials, the high and low temp limits

can be modified by other compounding ingredients.

Provides “baseline” for abrasion resistance, Provides “baseline” for abrasion resistance, compression set resistance, permeabilitycompression set resistance, permeability These can (and almost always are) modified – up

or down – by other compounding ingredients.

Compounding: Polymer SelectionCompounding: Polymer Selection

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Polymer chains must be cross-linked to achieve resilience Polymer chains must be cross-linked to achieve resilience and elasticity.and elasticity. Sulfur Organic Peroxides Bisphenol Others: specialty materials have special cure chemistry

Compounding: Cure SystemsCompounding: Cure Systems

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Reinforcing agents add mechanical strength and resistance Reinforcing agents add mechanical strength and resistance to abrasion & permeationto abrasion & permeation Carbon black: standard for black compounds Silica: standard for non-black compounds

Fillers lower the cost of a compound but reduce Fillers lower the cost of a compound but reduce compression set resistance and elongationcompression set resistance and elongation

Compounding: FillersCompounding: Fillers

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Oils and / or polymers to lower the low temp limits and Oils and / or polymers to lower the low temp limits and make the material flow better make the material flow better Reduce resistance to compression set In “generic” materials, they are used to offset the

hardening influence of high levels of filler Can extract into process fluids, resulting in seal

shrinkage & hardening

Compounding: PlasticizersCompounding: Plasticizers

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ndeformatioinitial

lossofamount

_

__

DI

FI

HHHHCS(%)

HI = Original HeightHD = Compressed HeightHF = Recovered Height

HIHD HF

Compression Set records the amount of permanent deformation of a compressed sample over time.

The Lower the Number, the Better Sealing Ability.

Compression Set

020406080

100

0 100 200 300 400

Hours

% L

oss

of

Com

pres

sion

Compression SetCompression Set

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High Temperature Compression Set Resistance @ 500 F

0

20

40

60

80

100

120

140

Hours

% L

oss

in D

efle

ctio

n 505

1050LF

6375

FF500

4079

FF200

70 500336168 1000 0

Performed on AS568A-214 O-rings (0.139" cross-section) at Parker Hannif in O-Ring Division, Lexington, KY

T H IS D O C UM EN T C O NT AI N S I N FO R MA T IO N T H AT I S C O N F I DE N TIA L AN D PR OP R IET A R YTO PAR KER S EA L O -R IN G D I VISIO N . TH I S D O C U M E NT I S FU R NI SH E D O N T H EUN D ERS T AN D IN G TH AT T H E D O C UM EN T AND T HE IN FO RM ATIO N IT CO N TAI NS W IL LNO T BE C OPI ED O R DIS C LO S ED TO O TH ER S OR U SE D FO R AN Y PU R PO SE O T H ERT H AN C ON D U C TI NG B US IN ES S W IT H PA R KE R, AN D W ILL B E R ET U R N ED AN D A L LF U RT HE R U SE D ISC O N T I NU E D UP O N R E Q U EST B Y PAR KE R. C O PY RI G H T PAR K ER.YE AR O F C OPY R IGH T IS F IR ST YE AR IN D IC ATED ON TH IS D O C U MEN T . AL L RI G H T SR ES ER V ED.

High Temp Compression SetHigh Temp Compression Set

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FS = “Spring Force”

FS

Compressive Stress Relaxation records drop in “Spring Force” over time generated by a compressed rubber sample.

The Higher the Number, the Better Sealing Ability.

Compressive Stress Relaxation

020406080

100

0 100 200 300 400

Hours

% In

itial

For

ce

Compressive Set RelaxationCompressive Set Relaxation

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High Temperature Compressive Stress Relaxation @ 392 F

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900 1000

Hours

% R

etai

ned

Seal

ing

Forc

e

FF200

FF500

1050LF

505

4079

6375

Performed on AS568A-325 O-rings (0.210" cross-section) at Parker Hannifin O-Ring Division, Lexington, KY

70 168 336

TH IS D O C U M E N T CO N T AI N S IN F OR M A T IO N T H A T I S C O N F I DE N T IA L A ND PR O P R I ET A R YTO PA R KE R S E A L O -R I NG D IV IS IO N . T H I S D O C U M E N T I S F U R NI S H E D ON T HEU N D E R S T A N D IN G T H A T T HE D O C U M EN T A N D T H E IN F O R M A T I O N IT C ON T A IN S W IL LN O T B E C O PI E D OR D I SC LOS E D T O O T H E RS OR U S ED FO R A N Y P U R P O S E O TH E RT H AN C O N D U C T IN G BU S IN E S S W IT H P A R K E R , AN D W IL L B E R E T U R N E D A ND AL LFU RT H E R US E D I SC O N T IN U E D U P O N R EQ U ES T BY PA R K E R. C O PY R I G H T PA R K E R.Y E AR O F C O PY R I G H T IS F IR S T Y E A R I ND IC A T E D ON T H IS D O C U M E N T . A L L R IG H T SRE S E R V E D.

Compressive Set RelaxationCompressive Set Relaxation

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O-Ring Design Is Easy!O-Ring Design Is Easy!

It’s the O-Ring groove that needs special attentionIt’s the O-Ring groove that needs special attention

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What makes a reliable O-ring design?What makes a reliable O-ring design? Squeeze

Seal deforms significantly (~25%) Rubber does not compress or lose volume

Stretch Gland fill

Volume-to-void ratio Surface finish

Balance of machining costs with application & testing needs

Installation Protect seal from sharp edges Provide lead-in chamfers

O-Ring Design O-Ring Design

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Compression expressed as a percentage of the Compression expressed as a percentage of the free-state cross-sectional thickness of the O-ring.free-state cross-sectional thickness of the O-ring.

(O-Ring C/S) - Gland Depth(O-Ring C/S) - Gland Depth

(O-Ring C/S)(O-Ring C/S)Face Seal:Face Seal: 20-30%20-30%Static Male/Female:Static Male/Female: 18-25%18-25%Reciprocating:Reciprocating: 10-20%10-20%Rotary:Rotary: 0-10%0-10%

O-Ring SqueezeO-Ring Squeeze

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O-Ring volume as a percentage of Gland O-Ring volume as a percentage of Gland volume.volume.

(O-Ring Volume)(O-Ring Volume)(Gland Volume)(Gland Volume)

About 25% void space or 75% nominal fillAbout 25% void space or 75% nominal fill Need space in groove to allow for volume swell,

thermal expansion, and increasing width due to squeeze

O-Ring Gland FillO-Ring Gland Fill

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O-Ring Gland FillO-Ring Gland Fill

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www.parkerorings.com www.parofluor.com

Website ResourcesWebsite Resources




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AcknowledgementsAcknowledgements

Dan Ewing, Seal Application

Engineering Manager

Natalie Hicks, Seal Application

Engineering Manager

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Patent PendingParker IntraFlowIntraFlow™™

Thank You!Thank You!

Documents

Elastomeric Seal