PTFE Oil Seals & High-Performance Rotary Shaft Seals

Stainless steel case with PTFE lip for chemicals, heat, high speed and dry-running service

Overview

PTFE oil seals combine the structural retention of a stainless steel outer case with the exceptional material properties of a polytetrafluoroethylene sealing lip. PTFE is chemically inert to virtually all industrial fluids, stable from cryogenic temperatures to +260°C, and capable of running with minimal lubrication or in intermittent dry contact. These characteristics make PTFE oil seals the preferred choice for process pumps, chemical compressors, semiconductor equipment, cryogenic expanders and high-speed spindles where conventional rubber seals would harden, swell, degrade or generate excessive friction. The PTFE lip is typically manufactured as a thin, flexible wafer or ribbon energized by a metallic garter spring or an elastomer secondary seal. The spring maintains contact pressure against the shaft despite PTFE's lack of elastic recovery. Some designs use a PTFE lip bonded to an elastomer backing ring, combining the chemical resistance of PTFE with the elasticity of FKM or NBR. Filled PTFE grades—with carbon, graphite, glass or MoS2—improve wear resistance, thermal conductivity and dimensional stability in aggressive dynamic service. Stainless steel cases are standard for PTFE oil seals because they resist the corrosive media commonly found in PTFE applications. The case provides a press-fit in the housing bore and protects the thin PTFE lip during installation. Shaft hardness and surface finish are critical for PTFE seal life: a hardened shaft above 55 HRC with Ra 0.1–0.4 µm and no circumferential marks gives the best results. Unlike rubber, PTFE does not recover from deep scratches on the shaft, so counter-surface quality is more important. Our PTFE oil seals are supplied in standard inch and metric sizes and can be manufactured to custom dimensions, lip angles and spring loads. Common applications include magnetic-drive pumps, cryogenic valves, chemical agitators, dry-running compressors, semiconductor wafer handling equipment and food-processing machinery requiring FDA-compliant materials.

PTFE Oil Seal Types

Spring-Energized PTFE Oil Seals

A corrosion-resistant garter spring energizes the PTFE lip against the shaft. Provides consistent sealing force across wide temperature and pressure ranges.

Best for: Process pumps, compressors, high-speed spindles

Elastomer-Backed PTFE Seals

PTFE sealing surface bonded to an FKM or NBR backing ring. Combines PTFE chemical resistance with elastomer elasticity for easier installation.

Best for: Chemical processing, food equipment, moderate pressure

Filled PTFE Oil Seals

PTFE compounded with carbon, graphite, glass or MoS2 fillers for improved wear, heat dissipation and dimensional stability.

Best for: Abrasive media, dry running, high PV applications

Custom PTFE Lip Seals

Manufactured to drawing with specific ID, OD, width, lip geometry, spring load and filler system.

Best for: OEM replacement, prototype development, special envelopes

Materials

Material	Properties	Best For
Virgin PTFE	-200°C to +260°C; lowest friction; universal chemical resistance; limited wear resistance without filler	Food, pharmaceutical, chemical and cryogenic service
Carbon-Filled PTFE	Improved wear resistance and thermal conductivity; low friction; anti-static	Dry-running compressors, pumps, dynamic service
Graphite-Filled PTFE	Self-lubricating; reduced stick-slip; good wear resistance in aqueous and chemical media	Water pumps, chemical agitators, low-lubrication service
Glass-Filled PTFE	Higher stiffness and creep resistance; improved dimensional stability under load	High-pressure static or slow rotary seals

Sizing

PTFE oil seals are specified by shaft diameter, bore diameter and width, just like rubber oil seals. Because PTFE has no elastic recovery, the lip design and spring energizer must be matched to the shaft diameter, speed and pressure. Custom designs are common.

Standard Metric PTFE Seals

• Common shaft diameters: 10–200 mm
• Standard widths: 7, 8, 10, 12 mm
• 304SS case standard; 316SS optional

Custom PTFE Seals

• Any ID, OD and width per drawing
• Choice of filler and spring material
• Prototype MOQ from 1 piece

Frequently Asked Questions

What are the temperature limits of PTFE oil seals?

Virgin PTFE oil seals operate from approximately -200°C to +260°C. The practical upper limit may be reduced by the spring material and case design, but PTFE itself remains stable across this entire range.

Are PTFE oil seals suitable for dry running?

Yes. PTFE's low coefficient of friction and anti-stick characteristics make it one of the best materials for dry-running or marginally lubricated rotary seals. Filled grades further improve wear resistance under boundary lubrication.

What shaft hardness is required for PTFE seals?

A minimum shaft hardness of 45 HRC is recommended; 55 HRC or higher is preferred for long life in abrasive or high-speed service. The shaft surface should be polished to Ra 0.1–0.4 µm without circumferential tool marks.

Can PTFE oil seals replace rubber seals in chemical pumps?

Yes. PTFE seals are widely used in chemical pumps, magnetic-drive pumps and process equipment where the pumped media attacks NBR or FKM. Verify that the pressure, speed and spring design are suitable for the application.

Do PTFE oil seals need a garter spring?

Most PTFE oil seals use a garter spring or elastomer energizer because PTFE has no elastic memory. The spring maintains lip contact force as the PTFE relaxes over time and compensates for thermal expansion.

What fillers are best for abrasive service?

Carbon, graphite and MoS2 fillers improve wear resistance and lubricity in abrasive or dry-running conditions. Glass-filled PTFE improves stiffness but can be more abrasive to the shaft, so it is used mainly for static or slow-rotary seals.