Evolution of the Butterfly Valve Seal

	Resilient Seal Original butterfly valve had shaft penetration through the seal plane.  Dowel pin through disc and shaft often leaked.  Note the interference between the seal and the disc which is needed to effect a tight seal.  This will wear with use and eventually leak.
		High Performance Seal The next step in butterfly valve evolution was to move the shaft from the seal plane.  Dowel pin parallel to disc does not leak.  Note that this design also relies upon interference for sealing and will also eventually leak.
			Score-TRICENTRIC® Metal Seal The triple eccentricity with the metal seal is the final step in the evolution.  Square keys are utilized for torque transmission.  Since there is no interference between mating parts during closure, seal wear is eliminated and the seal actually becomes tighter with use.  Tight shut-off up to 1200°F.

Score-TRICENTRIC^® Seal  |  Evolution of Butterfly Valve Seal 

Score-TRICENTRIC^® Sealing System  |  Score-TRICENTRIC^® Disc Seal