Series 56/57 Resilient Seated Butterfly Valve for Higher Pressures, Wafer and Lug

Resilient seated butterfly valve for higher pressures in wafer (Series 56) or lug (Series 57) pattern, rated 285 PSIG (PN 20) from 2" to 24" and 230 PSIG (PN 16) from 26" to 48". Upper and lower stems with square or double-D drive remove the need for disc screws or taper pins, and "Bear-G" bearings at both stem ends reduce friction and isolate the stem from the valve body.

Body style

Series 56: Wafer; Series 57: Lug

Body

CI, DI, CS, SS

Disc

Nylon coated Ductile Iron, Aroxy Ductile Iron, CF8M, NAB

Stem

410 SS, 17-4 PH, 316 SS

Seat

EPDM, Buna-N, FKM

Size range

2" to 48" (DN 50 to 1200)

Pressure rating

2" to 24": 285 PSIG (PN 20); 26" to 48": 230 PSIG (PN 16)

Design standard

API 609, BS EN 593

Testing standard

API 598, BS EN 12266-1

Features

ISO 5211 top plate for direct mounting of a wide range of actuators, handles, and gears; high strength disc with polished edge and hubs; upper and lower stem with square or double-D drive eliminates the need for disc screws or taper pins; double moulded O-rings provide upper and lower secondary seals; heavy duty bushing absorbs forces acting on disc-stem assembly due to line pressure; "Bear-G" bearings on drive and non-drive end stem reduce friction and isolate stem from valve body; bi-directional U-cup stem seal