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Proper Elastomeric Seal Selection for Process Analyzer Sample Systems

Proper Elastomeric Seal Selection for Process Analyzer Sample Systems. Steve Doe Parker Hannifin Corporation. Topics Elastomeric Seals & NeSSI Compounding O-Ring Design Chemical Compatibility. Proper Elastomeric Seal Selection for Process Analyzer Sample Systems. Elastomeric Seals & NeSSI.

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Proper Elastomeric Seal Selection for Process Analyzer Sample Systems

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  1. Proper Elastomeric Seal Selection for Process Analyzer Sample Systems Steve Doe Parker Hannifin Corporation

  2. Topics • Elastomeric Seals & NeSSI • Compounding • O-Ring Design • Chemical Compatibility Proper Elastomeric Seal Selection for Process Analyzer Sample Systems

  3. Elastomeric Seals & NeSSI No Matter Which System...

  4. Elastomeric Seals & NeSSI …Elastomeric Seals Are In The Picture!

  5. IntraFlow Pressure Connector R-Max Surface Mount Interface (not SP76) SP76 Interface Don’t: Expose Seal ID to Fluid Flow Do: “Capture” • Elastomeric Seals & NeSSI Seal Do’s & Don’ts

  6. Metal and plastic retained elastomeric composite seals • Polymeric and plastic seals • Homogeneous and inserted elastomeric shapes • Elastomeric O-Rings • Rubber and plastic boots/bellows • Extruded and precision-cut and fabricated elastomeric seals • Thermoplastic engineered seals • EMI shielding and thermal management products • Seal Group Products

  7. Mold Onto Stainless Wafer • Elastomeric Seals & NeSSI • Alternatives: • Special Geometry O-Ring Seal • Stick With 2-007 in Couterbore (what we have)

  8. “… designs and manufactures engineered elastomeric o-ring seals.” • Parker O-Ring Division

  9. Failure Modes Extrusion & Nibbling Spiral Failure Cutting Explosive Decompression

  10. The seal swells, shrinks, loses physical properties, or gets 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 Modes Chemical Attack

  11. Butyl (IIR) Neoprene (CR) Ethylene-Propylene (EPR, EPDM) Fluorosilicone (FVMQ) Nitrile (NBR) Polyacrylate (ACM) Hydrogenated Nitrile (HNBR) Polyurethane (AU, EU) Silicone (VMQ) Fluorocarbon (FKM) Tetrafluoroethylene-Propylene (TFE/P) Perfluoroelastomer (FFKM) • O-Ring Polymers

  12. GLT V0835-75 A V1164-75 B V0834-75 Extreme V1260-75 GFLT V1163-75 GF V0965-80 Hifluor V3819-75 NEW V1263-75 ParofluorTM V8545-75 • Performance of Fluorocarbon

  13. Performance of Fluorocarbon

  14. Parofluor™ Ultra 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 enhance physical & thermal properties

  15. Physical Properties FF500-75 FF200-75 Chemraz 505 Kalrez 4079 Kalrez 1050 Kalrez 6375 Durometer, Shore A 75 75 75 75 80 75 Tensile Strength, psi 2045 1740 1750 2450 2700 2200 Modulus at 100%, psi 1262 1131 1150 1050 1800 1050 Elongation, % 135 124 140 150 125 160 TR – 10, F +6 +5 +5 - - - Temperature Range, F 5 to 525 5 to 608 5 to 446 to 600 to 550 to 527 30 Compression Set, 70 hrs at 400F, % (2-214 O-rings) 19 16 25 25 35 • Parofluor™ Ultra

  16. Parofluor™ Ultra

  17. Base polymer determines chemical resistance, rough temperature 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, compression set resistance, permeability • These can (and almost always are) modified – up or down – by other compounding ingredients. • Compounding: Polymer Selection

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

  19. Reinforcing agents add mechanical strength and resistance to abrasion & permeation • Carbon black: standard for black compounds • Silica: standard for non-black compounds • Fillers lower the cost of a compound but reduce compression set resistance and elongation • Compounding: Fillers

  20. Oils and / or polymers to lower the low temp limits and 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: Plasticizers

  21. Compression Set HD HF HI HI = Original Height HD = Compressed Height HF = Recovered Height Compression Set records the amount of permanent deformation of a compressed sample over time. The Lower the Number, the Better Sealing Ability.

  22. High Temp Compression Set

  23. Compressive Set Relaxation FS FS = “Spring Force” Compressive Stress Relaxation records drop in “Spring Force” over time generated by a compressed rubber sample. The Higher the Number, the Better Sealing Ability.

  24. Compressive Set Relaxation

  25. O-Ring Design Is Easy! It’s the O-Ring groove that needs special attention

  26. 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

  27. Compression expressed as a percentage of the free-state cross-sectional thickness of the O-ring. • (O-Ring C/S) - Gland Depth • (O-Ring C/S) • Face Seal: 20-30% • Static Male/Female: 18-25% • Reciprocating: 10-20% • Rotary: 0-10% • O-Ring Squeeze

  28. O-Ring volume as a percentage of Gland volume. • (O-Ring Volume) • (Gland Volume) • About 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 Fill

  29. O-Ring Gland Fill

  30. Website Resources www.parkerorings.com www.parofluor.com

  31. Website Resources

  32. Website Resources

  33. Website Resources

  34. Acknowledgements Dan Ewing, Seal Application Engineering Manager Natalie Hicks, Seal Application Engineering Manager

  35. Parker IntraFlow™ Patent Pending Thank You!

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