Rotary Seal Design Guide - Seals Unlimited

Catalog EPS 5350/USAEngineeringCantilever Springs — V SeriesThe FlexiSeal Cantilever spring ismade from flat metal strip stock of300 Series stainless steel or Elgiloy ® *as an option. The strip stock is punchedor chemically etched into a serpentinepattern and formed into a rounded“V” shape. It is available in either a lightor medium load spring. The mediumspring is suitable in most applications,but the light load spring can be used ifhaving low friction is more importantthan sealability. The medium springload deflection curve is depicted inFigure 2-14 on Page 2-16.The cantilever spring is intended fordynamic applications involving rotary orreciprocating motion. It can also beused in static conditions when there isneed for a higher deflection spring dueto wide gland tolerance, excessiveexpansion and contraction, or lift-offdue to high pressure.The long beam leg design puts thespring load out at the leading edge ofthe seal, creating the best load locationfor the FlexiSeal to act as a scraperwhen the optional scraper lip is selected.The geometry of the V Seriescantilever spring provides flexibility byutilizing individual tabs, separated bysmall gaps. This shape allows thespring to flex into radial and axial sealdesigns. The spring tabs can overlapon the ID and spread apart on the ODwhen the cross-section is too large forthe diameter.Table 2-4 provides the minimumdiameters for V Series springs for rodand piston seals, as well as internaland external pressure face seals. Fordiameters smaller than those listed,C or H Series spring designs arerecommended.Table 2-4. Minimum Diameters for V SeriesNominalCross-SectionFeaturesRodShaftDia.• V-shaped spring with moderate load vs. deflection• Standard inch/fractional and MIL-G-5514 sizes• Standard 300 series stainless steel springs• NACE compliant Elgiloy springs available in medium springload, -450 to 600 °F• Scraper lip designs for abrasive medias• Available as external & internal pressure face sealsRecommended Applications• Reciprocating rods & pistons• Rotary shafts