Lug Butterfly Valve Suppliers & Manufacturer

A wafer butterfly valve features plain unthreaded centering lugs designed merely to position the valve body between two pipeline flanges using long continuous studs. In contrast, a lug butterfly valve incorporates threaded, tapped metal lugs matching the bolt pattern of the connecting flanges (such as ASME B16.5 Class 150 or EN 1092-1 PN16). This configuration allows each flange to be bolted with separate, dedicated studs, enabling true dead-end service—where piping on one side of the valve can be removed while full line pressure is safely held on the other side.

Yes. Concentric resilient-seated lug butterfly valves from Tianjin Top Valve feature a precision-machined spherical disc edge and a symmetrical molded elastomer seat. This guarantees zero-leakage, bubble-tight shut-off in both directions across full rated pressures (PN10/PN16/Class 150). However, in dead-end service conditions, the pressure rating might be derated slightly depending on whether the flow direction is toward or away from the retaining seat ring.

Because lug holes are threaded, the body casting must be drilled and tapped to match specific regional bolt thread and pitch requirements. We support all major international standards:
• ASME/ANSI: B16.1 Class 125, B16.5 Class 150 (UNC threading)
• European / DIN: EN 1092-1, DIN 2501 PN10, PN16, PN25 (Metric threading)
• British: BS 4504, BS 10 Table D / E
• Japanese: JIS B2220 / B2239 10K / 16K

Most valve assembly facilities purchase vulcanized rubber boots from outsourced rubber vendors, which often results in variable polymer density and poor compression recovery. Operating our dedicated rubber facility (Tianjin Dongfang Rubber, since 1987) allows us to compound our own high-polymer formulations with strict control over carbon black content, anti-aging agents, and curing kinetics. This ensures high tear strength, superior chemical resilience, and WRAS compliance for potable water services.

Every production batch undergoes 100% hydrostatic shell testing (1.5x design pressure) and high-pressure seat leakage testing (1.1x design pressure) in compliance with ISO 5208 and API 598. In addition, low-pressure pneumatic air tests (0.6 MPa) verify zero seat bubble leakage. Castings are audited for chemical composition and tensile elongation, and epoxy powder coatings are verified with digital holiday detectors and thickness micrometers (typically ≥250 microns).