O-ring seal

PTFEroundfor the petrochemical industry

Definition
A PTFE O-ring is an endless circular ring with a round cross section used primarily as an axial static seal. Sealing is achieved by compressing the cross section in the groove. Because PTFE exhibits minimal elasticity, an expansion slot is incorporated around the circumference; this slot must remain on the pressure side.

Fields of application
PTFE O-rings are specified where elastomer O-rings cannot meet thermal or chemical resistance requirements. Their chemical compatibility, physiological inertness and sterilizability make them suitable for chemical, petrochemical, pharmaceutical and food industry applications.

Common uses / Actuation types

• static
• dynamic
• single acting
• double acting
• linear
• rotating (not recommended / inactive in some designs)
• oscillating

Main use
A simple axial static seal offering excellent thermal and chemical resistance.

Materials
PTFE, PTFE with fillers

Advantages

• high chemical resistance
• temperature resistance from -200°C up to +260°C (material dependent)
• good sliding properties
• physiologically inert and sterilizable
• suitable for food, chemical and petrochemical industries
• low coefficient of friction

Field of application (details)
Use PTFE O-rings when elastomer rings cannot withstand required temperatures or aggressive media. PTFE is compatible with most media; main limitations are certain fluorine and halogen compounds and liquid alkali metals. Their resistance and sterilizability explain common use in petrochemical, food, chemical and pharmaceutical sectors.

Main fields of application

• static sealing between flanges, housing parts and covers

Operating parameters
Operating limits must be assessed collectively; maximum temperature, speed and pressure cannot be applied simultaneously. Values depend on material and media.

Technical values
Materials: PTFE, PTFE with fillers
Pressure: up to 40 MPa
Temperature: -200°C to +260°C (material dependent)
Speed: not applicable / no specific value indicated

Definition of dimensions and ordering sizes
• Inside diameter (d1): from approx. 3 mm
• Cross section (d2): approx. 0.5 mm to 12 mm

Installation notes
PTFE O-rings have very limited stretch and compression. The cross section must match the groove depth; the expansion slot must face the pressure side. Install in easily accessible split grooves. Avoid triangular groove designs (types B & C) that prevent defined slot positioning.

Technical specifications

• Product: PTFE O-ring
• Materials: PTFE, PTFE with fillers
• Pressure rating: up to 40 MPa
• Temperature range: -200°C to +260°C (material dependent)
• Speed: not specified / not applicable
• Inside diameter (d1): from approx. 3 mm
• Cross section (d2): approx. 0.5 mm to 12 mm
• Main application: axial static sealing (between flanges, housing parts and covers)
• Installation requirement: expansion slot must face pressure side; use split grooves; avoid triangular groove types