Lug

Lug type butterfly valves are used for isolation or limited throttling duty in industrial water networks, HVAC systems, cooling circuits, compressed air, inert gases, and compatible process liquids. The lugged body configuration allows bolting directly to the mating pipe flanges and may permit end-of-line service, subject to the manufacturer’s approval, operating pressure, and installation load direction.

This category includes ARI, Alfa Europe, Comeval, and TTV versions, with DIN, ANSI, and JIS drilling standards. Available pressure classes include PN 6, PN 10, PN 16, PN 25, ANSI Class 150, and JIS 5K/10K, with lugged flange connection. Body materials include EN-JS 1030 / GGG40 ductile iron, EN-JL 1040 / GG25 cast iron, EN-GJL-250, ASTM A216 WCB, 1.4408 stainless steel, carbon steel, stainless steel, and aluminium bronze BS 1400 AB2, depending on the service medium and operating environment.

Seat selection determines the allowable temperature range, chemical compatibility, and shut-off performance. EPDM is typically used for water and HVAC duty, NBR for air service or media containing oil traces, while FPM/FKM and PTFE-based configurations are considered for chemically aggressive or higher-temperature applications. Silicone seats and PTFE-lined combinations are also available where different corrosion resistance or cleaning requirements apply.

Valve selection should verify DN, pressure rating, flange drilling standard, maximum differential pressure, operating torque, disc and stem material, elastomer compatibility with the process medium, and whether maintenance can be carried out without removing the full piping section. Operation may be by lever, gearbox, pneumatic actuator, or electric actuator, with actuator sizing based on differential pressure, cycling frequency, and required fail position in automated systems.