Hygienic butterfly valves for sanitary and aseptic applications have been developed by Tyco Valves & Controls. The Keystone stainless steel F250 (for imperial tube configurations) and F251 (for metric) valves are designed for isolation and flow control duties, and can be supplied with standard butt weld and threaded end connections, or in a unique wafer-flanged configuration for applications involving minimal pipe separation. Both valve types are supplied with a 316L stainless body as standard. The wafer weld configuration features integral butt weld flanges, separated by two stainless steel jacking bolts. This facilitates removal of the centre valve section for maintenance or replacement, without disturbing the connecting process pipeline. This configuration allows cost and time savings, reduction in plant downtime, and facilitates spares identification. The valves are available with food grade seat and seal material options. Acetal bearings above and below the valve seat decrease torque and extend seat life. Standard features include integral valve position indicator, a mirror polished, high Cv slim profile disc, high impact stainless steel lockable lever with throttling facility, and integral padlocking. This high impact description is relative to the nylon lever only and should be removed in total. F250 and 251 are offered with a full range of optional actuation and control accessories. Actuators can be connected and disconnected without removing the valve from the process pipeline. The fig 783 IP67 Control head features an integral solenoid with throttling of both open and closed exhausts, which enables speed control in both directions of operation. Suitable for pressures from full vacuum to 1000kPa and temperatures from -10°C to +95°C, the valve body is constructed from 316L stainless steel. End connection sizes range from 25mm to 150mm. Fig 250 and 251 are also available as part of a network solutions package, compatible with leading fieldbus protocols.