PTFE Lip Seals
PTFE Canned Lip seals offer press-in-place installation, with strong retention in the hardware housing.
Flanged PTFE Lip seals offer the ability for a flange to be bolted into the housing to guarantee no rotation of the seal within the hardware.
For slower FPS rotary applications, an elastomeric o-ring is sufficient to provide anti-rotational properties respective to the shaft.
Advances in radial lip seal technology has focused on the evolution from elastomeric spring loaded lip seals, to thermoplastic materials with innovative lip designs for both inclusion and exclusionary sealing requirements. The pressure, temperature and chemical compatibility of contemporary PTFE lip seals are sufficient to perform satisfactorily across a range of rotary applications, and at a fraction of the cost of their mechanical seal counterparts. This category of rotary shaft seals perform exceptionally well with regard to friction and stick-slip running. Furthermore, the material memory of PTFE is utilized to provide the necessary radial loading on the shaft, which allows profiles to seal without a spring.
Non-encased lip seals have the least tolerance for pressure and surface speed, up to 150 psi and 6,000 sfpm respectively. However, compared to their elastomeric counterparts solve many problems with respect to chemical compatibility, temperature (both high and low) and custom lip geometry. A number of standard lip geometries exist to optimize both inclusion and exclusion requirements, and in addition to these profiles any number of custom variations can be machined due to the versatile and efficient manufacturing process.
Metal encased or 'Canned' PTFE radial lip seal should be considered in pressure limits from 150 psi to 500 psi and the surface speed limits rise from 6,000 sfpm to 10,000 sfpm. A gasket is placed between the 'Can' and the sealing lips to avoid potential leak paths. Gasket materials are the same as the retention Oring for the non-encased radial lip seals. Metal case materials include stainless steel, cold-rolled steel, zinc-plated cold rolled steel and aluminum.
Mouse over the above images to learn more about these products. Consult a Gallagher Engineer with specific application questions.