AWWA C504 Double Eccentric Flanged Butterfly Valve

Design Features

Metalsin supplies AWWA C504 flanged double eccentric butterfly valves to various waterworks pipelines. The double eccentric butterfly valve, also known as a double offset butterfly valve, features a design where the valve stem is offset from both the centerline of the disc and the centerline of the valve body. The first eccentricity is the offset between the valve shaft and the centerline of the valve disc, allowing the disc to quickly move away from the rubber seat during opening, which reduces friction and wear. The second eccentricity is the offset between the centerline of the valve body and the seating surface of the disc, enabling the disc to create a tight seal through a wedging action when closing. Compared to concentric butterfly valves, this double-eccentric configuration ensures that the disc disengages from the rubber seat early during opening, significantly reducing friction and wear. It enhances the sealing performance as well as improves the valve’s service lifespan.

The typical picture and drawing of AWWA C504 double eccentric flanged butterfly valve, rubber seated.

Other design features include: (1) In full compliance with technical requirements of AWWA C504; (2) The rubber seat ring is clamped firmly on the edge of the disc; (3) The body seating surface is weld overlaid with stainless steel, brass or bronze alloy; (4) Bare stem with ISO 5211 mounting pad to suit for various actuators; (5) Flange and drilling in compliance with ASME B16.1 Class 125 or Class 250; (6) Fusion-bonded-epoxy (FBE) coatings on both interior and exterior surface of the valve according to AWWA C550 and ANSI/NSF 61.

Main Parts & Material Selection

Sizes & Dimensions