- High chemical resistance
- Withstand speeds up to 30 m/s (5 900 ft/min)
- Wide operating temperature range, –70 to +250 °C (–95 to +480 °F)
- Withstand pressures up to 3,5 MPa (500 psi)
- Withstand dry running
AssortmentThe profiles shown are a selection of the most commonly used SKF seal designs with sealing lips made of PTFE. They can be installed in existing housing grooves where traditional radial seals are used, provided that the grooves are manufactured in accordance with international standards.
There are two main executions of PTFE seals: those with a metal case SL (fig 1), SLX (fig 2), SLS (fig 3), SLA (fig 4), DL (fig 5) and DLA (fig 6) and those without a metal case (YSLE (fig 7), YNSLE (fig 8) and YSL (fig 9). The metal case can be made of steel, aluminium or any of the stainless steel materials SS 304, SS 316 and SS 316 TI. The PTFE material should be selected based on the needs of the application.
PTFE seals without a metal case can be designed with an O-ring in the outside diameter groove to provide static sealing ability. Both the PTFE and O-ring material can be selected to meet the demands of different operating conditions, e.g. in the food industry to enable disassembly of the equipment for cleaning.
PTFE materialsThe selection of seal materials typically requires a compromise between advantages and disadvantages. There are hundreds of different PTFE materials with a variety of fillers. Common fillers include glass fibre, carbon, graphite, molybdenum disulphide, metal oxides and various polymers. Each possesses different properties, appropriate for different applications and service conditions. Common to all filled PTFE materials are their improved resistance to wear and deformation.
Unfilled PTFE provides, in most cases, a lower coefficient of friction than a filled PTFE material and the lowest degree of wear of the seal counterface. However, a sealing lip made of an unfilled PTFE material has limited resistance to wear and deformation under load.
The PTFE materials that SKF most often recommends are listed in the table. In addition to PTFE-based compounds, SKF also offers radial shaft seals in other modified plastics, some of which are listed in the table.
Selecting the appropriate material for the metal case and the O-ring(s) is also of significant importance to achieving satisfactory sealing performance. Contact SKF for additional information.