Custom Lug Type Valve Manufacturer & Factory

A wafer butterfly valve features smooth unthreaded positioning holes and is sandwiched between two pipe flanges using long all-thread studs. In contrast, a lug butterfly valve features threaded metallic lugs protruding outward around the valve body casing. This permits individual bolts to be threaded directly into the body from both sides, enabling bi-directional dead-end isolation where one side of the piping line can be entirely dismantled for downstream maintenance while the upstream pipeline remains under full operating pressure.

Yes, high-quality lug valves designed per API 609 or BS EN 593 are explicitly rated for bi-directional dead-end service. However, it is critical to specify dead-end rating requirements during procurement. Soft-seated lug valves manufactured by KR Valve are engineered with internal mechanical retention rings or molded-in body liners to ensure the seat ring remains fully stabilized even when the downstream counter-flange is removed.

Selecting the ideal liner elastomer depends on chemical composition, fluid concentration, and thermal range:

• EPDM: Excellent for water, steam, HVAC chilled water, and mild alkalis (-20°C to +120°C). Not suitable for oils or hydrocarbons.
• NBR (Buna-N): Ideal for petroleum oils, fuel gases, compressed air, and hydraulic fluids (-10°C to +80°C).
• FKM (Viton): Superior for aggressive chemicals, hot oils, acidic media, and high temperatures (-15°C to +200°C).
• PTFE / RTFE: Universal chemical inertness for corrosive acids, solvents, and high-purity media (-30°C to +180°C).

Our CNC machining centers tap lug threads to match any major international flange drilling standard requested, including ASME B16.5 Class 150 / Class 300, EN 1092-2 (PN10, PN16, PN25, PN40), BS 10 (Table D/E), AS 4087, and JIS B2220 10K/16K. Dual-drilled multi-standard lug patterns can also be produced for international replacement programs.

We provide end-to-end custom valve manufacturing including customized body casting molds (with client logo/brand), tailored face-to-face dimensions, specific fusion-bonded epoxy coating thicknesses (up to 300 microns), custom disc material overlays (such as Stellite hard-facing), customized actuator mounting brackets, specialized tagging, and dedicated third-party inspection (TUV, SGS, BV) coordination.

Operating torque is dictated by differential line pressure, fluid viscosity, seat interference fit, packing friction, and dynamic flow torque. Our engineering team utilizes finite element analysis (FEA) and computational fluid dynamics (CFD) modeling to provide exact safety-factored torque charts (typically adding a 25-30% safety margin) to assist customers in properly sizing electric or pneumatic actuators without over-torquing the valve stem.