A Glossary of Fluoropolymer and Lined Valve Terms

Introduction

Fluoropolymers and lined valves are widely used in industries requiring high chemical resistance, thermal stability, and low friction properties. This glossary provides definitions of key terms related to fluoropolymer materials, valve construction, and lined valve technology.

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A

Additive Manufacturing (3D Printing) – A process used to create fluoropolymer components layer by layer, allowing for complex geometries that may be difficult to achieve with traditional molding techniques.

Adhesion Promoter – A chemical treatment applied to metal substrates to improve the bonding of fluoropolymer linings.

Annealing – A heat treatment process used to relieve internal stresses in fluoropolymer components, improving dimensional stability and mechanical properties.

ASME BPE (Bioprocessing Equipment) – A standard for valves and piping systems in pharmaceutical and biotech industries, often requiring fluoropolymer linings for corrosion resistance.

Autoclave – A high-pressure vessel used to cure or sinter fluoropolymer linings onto metal valve bodies.

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B

Back Pressure – The resistance to flow in a piping system, which can affect the performance of lined valves.

Ball Valve – A quarter-turn valve with a fluoropolymer-lined spherical disc that controls flow.

Burst Pressure – The maximum pressure a fluoropolymer-lined valve can withstand before failure.

Butterfly Valve – A valve with a fluoropolymer-lined disc that rotates to regulate flow, commonly used in large-diameter applications.

Butt Welding – A joining method for fluoropolymer-lined pipes and fittings, ensuring a leak-free connection.

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C

Chemical Resistance – The ability of fluoropolymers to withstand aggressive chemicals without degradation.

Check Valve – A valve that allows flow in one direction only, often lined with fluoropolymers for corrosion resistance.

Compression Molding – A manufacturing process where fluoropolymer resin is heated and compressed into a mold to form linings or components.

Corrosion Resistance – The ability of fluoropolymer linings to protect metal valve bodies from chemical attack.

Cryogenic Service – Applications involving extremely low temperatures where fluoropolymer-lined valves maintain flexibility and sealing performance.

Curing – A process where fluoropolymer linings are heated to achieve full polymerization and adhesion to the substrate.

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D

Diaphragm Valve – A valve with a fluoropolymer diaphragm that flexes to control flow, ideal for sterile or high-purity applications.

Differential Pressure – The pressure difference across a valve, affecting flow control and sealing performance.

Dimensional Stability – The ability of fluoropolymer linings to maintain shape under temperature and pressure variations.

Double Block and Bleed (DBB) – A valve design with two sealing mechanisms and a bleed port for isolation and testing.

Durometer Hardness – A measure of fluoropolymer material hardness, affecting wear resistance and sealing properties.

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E

Elastomer – A flexible polymer sometimes used in conjunction with fluoropolymers for enhanced sealing.

Electrostatic Discharge (ESD) Safe – Fluoropolymer formulations modified to prevent static buildup, important in flammable environments.

End Connections – The type of fittings (flanged, threaded, welded) used to connect fluoropolymer-lined valves to piping systems.

Extrusion – A process where molten fluoropolymer is forced through a die to create linings or tubing.

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F

FEP (Fluorinated Ethylene Propylene) – A melt-processable fluoropolymer with excellent chemical resistance and clarity.

Flange – A rim used to connect valves to pipes, often lined with fluoropolymers for corrosion protection.

Flexural Strength – The ability of a fluoropolymer lining to resist bending without cracking.

Fluid Handling – Applications involving the transport of liquids or gases using fluoropolymer-lined valves.

Fugitive Emissions – Leakage of volatile compounds from valves; fluoropolymer linings help minimize emissions.

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G

Gate Valve – A valve with a fluoropolymer-lined gate that slides to control flow, used in full-open or full-close applications.

Gland Packing – A sealing method in valves, sometimes enhanced with fluoropolymer materials for chemical resistance.

Grit Blasting – A surface preparation technique to improve fluoropolymer lining adhesion.

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H

Hastelloy® – A high-performance alloy often used as a substrate for fluoropolymer-lined valves in extreme conditions.

Heat Tracing – A method to maintain temperature in fluoropolymer-lined systems, preventing crystallization at low temperatures.

Hydrostatic Testing – A pressure test to verify the integrity of fluoropolymer-lined valves before service.

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I

Injection Molding – A process where molten fluoropolymer is injected into a mold to form complex valve components.

ISO 15848 – A fugitive emissions standard for valves, often requiring fluoropolymer seals for compliance.

Isolation Valve – A valve designed to completely stop flow, often lined with fluoropolymers for long-term reliability.

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J

Jacketed Valve – A valve with an outer heating/cooling jacket, sometimes lined with fluoropolymers for thermal control.

JIS (Japanese Industrial Standard) – Standards for fluoropolymer-lined valves used in Japanese industries.

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K

Kynar® (PVDF) – A fluoropolymer with excellent chemical resistance and mechanical strength, commonly used in valve linings.

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L

Lapping – A finishing process to ensure smooth sealing surfaces in fluoropolymer-lined valves.

Lined Pipe – Pipes with fluoropolymer linings for corrosion resistance, often used with lined valves.

Lugged Valve – A valve with threaded inserts for easy installation between flanges.

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M

Melt Flow Index (MFI) – A measure of fluoropolymer resin flowability during processing.

MIL-SPEC – Military specifications for fluoropolymer-lined valves in defense applications.

Multi-Port Valve – A valve with multiple flow paths, sometimes lined with fluoropolymers for complex routing.

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N

NACE MR0175 – A standard for materials in sour (H₂S-containing) environments, often requiring fluoropolymer linings.

Non-Stick Properties – A key characteristic of fluoropolymers, preventing material buildup in valves.

NPT (National Pipe Thread) – A common threading standard for fluoropolymer-lined valves.

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O

O-Ring – A sealing element often made from fluoropolymers for chemical resistance.

Oxidation Resistance – The ability of fluoropolymers to resist degradation from oxygen exposure.

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P

PFA (Perfluoroalkoxy) – A high-purity fluoropolymer used in semiconductor and pharmaceutical valve linings.

Permeation – The diffusion of chemicals through fluoropolymer linings; low permeation is desirable.

PTFE (Polytetrafluoroethylene) – The most widely used fluoropolymer for valve linings due to its chemical inertness.

Pump Compatibility – The suitability of fluoropolymer-lined valves for use with corrosive fluid pumps.

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Q

Quarter-Turn Valve – A valve (e.g., ball or butterfly) requiring only a 90-degree turn to operate, often fluoropolymer-lined.

Quality Assurance (QA) – Testing procedures to ensure fluoropolymer-lined valves meet performance standards.

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R

Ra (Surface Roughness) – A measure of fluoropolymer lining smoothness, affecting flow efficiency.

Rotary Valve – A valve with a rotating mechanism, often lined with fluoropolymers for wear resistance.

Rupture Disc – A safety device sometimes lined with fluoropolymers to prevent overpressure in systems.

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S

Sanitary Valve – A valve designed for high-purity applications, often lined with fluoropolymers.

Seat – The sealing surface in a valve, often made from fluoropolymers for tight shutoff.

Stem – The valve component that transmits motion to the closure mechanism, sometimes coated with fluoropolymers.

Sulfuric Acid Resistance – A critical property of fluoropolymer linings in chemical processing.

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T

Teflon™ (PTFE) – A well-known brand of fluoropolymer used in valve linings.

Thermal Expansion – The dimensional change of fluoropolymers with temperature, affecting valve design.

Three-Way Valve – A valve with three ports for flow diversion, sometimes lined with fluoropolymers.

Tolerance – The allowable variation in fluoropolymer-lined valve dimensions.

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U

Ultra-High Purity (UHP) – Applications requiring fluoropolymer-lined valves with minimal contamination risk.

UV Resistance – The ability of some fluoropolymers to withstand ultraviolet light without degradation.

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V

Vacuum Service – Applications where fluoropolymer-lined valves must maintain sealing under negative pressure.

Viscosity – A factor in selecting fluoropolymer linings for high-viscosity fluid handling.

Viton® – A fluoroelastomer sometimes used in valve seals alongside fluoropolymers.

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W

Wafer Valve – A thin-profile valve installed between flanges, often lined with fluoropolymers.

Wear Resistance – The ability of fluoropolymer linings to withstand abrasion in slurry applications.

Wetted Parts – Valve components in direct contact with process fluids, typically lined with fluoropolymers.

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Conclusion

This glossary provides a comprehensive reference for key terms related to fluoropolymer and lined valve technology. Understanding these terms is essential for selecting, designing, and maintaining valves in corrosive, high-purity, and high-temperature applications.

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