Lug Type Butterfly Valves
The body of a lug type butterfly valve is surrounded by threaded lugs aligned with the flange holes. Each flange is bolted to these lugs with its own bolts, so the valve stays attached to the other flange even when one side of the line is removed.
This makes the lug body suitable for line ends and for points where the line will be opened for maintenance in front of pumps, strainers and heat exchangers. The lever-operated types here come with grey or ductile iron bodies and stainless, nickel-plated or aluminium bronze discs, in PN16 up to DN300.
Main Applications
- Points in front of pumps and strainers needing one-sided removal
- Maintenance isolation at heat exchanger and boiler connections
- Header ends and line ends to be extended later
- Cooling water and process water distribution lines
- Seawater and marine installations (bronze disc type)
- Sectioned line arrangements in treatment plants
Technical Data
| Connection | Lug; threaded lugs, separate bolts for each flange |
|---|---|
| Size range | DN25–DN600 (from DN40 for the bronze disc type) |
| Pressure class | PN16 (DN25–300) · PN10 (DN350–600) |
| Temperature | EPDM −10 / +130 °C · NBR −10 / +80 °C |
| Lug threads (PN16) | DN25: 4×M12 · DN50: 4×M16 · DN80–DN125: 8×M16 |
| Bolt circle (PN16) | DN50: 125 mm · DN100: 180 mm · DN125: 210 mm |
| Stem | SS420 (DN25–300) · SS431 (DN350–600) |
| Stem end | Square; 9×9 mm (DN40–80) · 11×11 mm (DN100) · 14×14 mm (DN125) |
| Weight | DN50: 3.5 kg · DN100: 6.7 kg · DN125: 9.6 kg (stainless disc type) |
| End-of-line use | Downstream flange can be removed; permissible pressure depending on model |
| Installation | Stem horizontal or vertical; horizontal recommended for DN300 |
| Operation | Lever; DN350 and above geared |
Material Options
| Part | PN16 · GG25 body, stainless disc | PN16 · GG25 body, nickel-plated disc | PN16 · ductile iron body, bronze disc |
|---|---|---|---|
| Body | Grey cast iron GG25, threaded lugs | Grey cast iron GG25, threaded lugs | Ductile iron GGG-40.3, threaded lugs |
| Disc | Stainless steel AISI 316 | Nickel-plated ductile iron GGG-40.3 | Aluminium bronze |
| Stem | SS420 (DN25–300) · SS431 (DN350–600) | SS420 (DN25–300) · SS431 (DN350–600) | SS420 (DN40–300) · SS431 (DN350–600) |
| Seat / liner | EPDM | EPDM | NBR |
| Working temperature | −10 / +130 °C | −10 / +130 °C | −10 / +80 °C |
| Pressure class | PN16 (DN25–300) · PN10 (DN350–600) | PN16 (DN25–300) · PN10 (DN350–600) | PN16 (DN40–300) · PN10 (DN350–600) |
With a lug valve at the end of a line, use without a blind flange on the open side should only be temporary, and the permissible pressure must be checked against the manufacturer value. Choose EPDM for hot water circuits and NBR for water up to 80 °C and oily media.
Advantages
One-Sided Removal
- The valve stays in place when one flange is opened.
- Shorter draining time during pump and strainer maintenance.
Self-Centring
- Lug holes line up with the flange holes.
- Prevents valve shifting and liner crushing at installation.
End-of-Line Service
- Provides isolation at headers and extension points.
- Connection point ready for future line additions.
Three Disc Options
- Stainless, nickel-plated or bronze.
- Suits water, heating and seawater circuits.
Construction and Design Features
- Cast body with threaded lugs aligned to the flange holes
- Elastomer liner that also acts as the flange gasket
- Disc rotating on a stainless steel stem
- Square stem end suitable for lever or actuator
- Supplied with gearbox from DN350 upwards
Request a quote for lever-operated lug type butterfly valves by stating size, flange standard, whether it will be used at a line end, and the medium.
How to Choose?
- Define the removal needChoose a lug body if equipment on one side will be removed separately or the valve will sit at a line end.
- Match lug threads to the flangeCheck that the PN16 flange hole count and bolt size match the lug threads.
- Select seat and discEPDM for hot water, NBR for water below 80 °C and oily media; bronze disc for seawater.
- Size the boltsEach flange is bolted to the lugs separately, so two short bolt sets are used; choose thread length to suit flange thickness.
Complementary Products
Why ORFA?
Other Butterfly Valves
Double Acting Pneumatic Lug Butterfly Valves
Double acting pneumatic lug butterfly valves are lug body valves opened and closed automatically by an actuator driven by air in both directions.
Details →
Double Acting Pneumatic Wafer Butterfly Valves
Double acting pneumatic wafer butterfly valves are wafer body valves automatically controlled by an actuator driven by air in both directions.
Details →
Electric Actuated Lug Type Butterfly Valves
Electric actuated lug type butterfly valves are lug body valves opened and closed remotely by an electric actuator.
Details →
Electric Actuated Wafer Butterfly Valves
Electric actuated wafer butterfly valves are wafer body valves controlled remotely or automatically by an electric actuator.
Details →PVC-U and PPRC Butterfly Valves
PVC-U and PPRC butterfly valves have corrosion resistant plastic bodies and are used in water treatment and chemical lines.
Details →
Gear Operated Lug Type Butterfly Valves
Gear operated lug type butterfly valves are lug body valves opened and closed easily and gradually with a handwheel and gearbox.
Details →
Gear Operated Wafer Butterfly Valves
Gear operated wafer butterfly valves are wafer body valves with a handwheel and gearbox for easy operation in large sizes.
Details →
Single Acting Pneumatic Lug Butterfly Valves
Single acting pneumatic lug butterfly valves are lug body valves whose spring return actuator moves to a safe position when air fails.
Details →
Single Acting Pneumatic Wafer Butterfly Valves
Single acting pneumatic wafer butterfly valves are wafer body valves whose spring return actuator moves to a safe position when air fails.
Details →
Wafer Type Butterfly Valves
Wafer type butterfly valves are lightweight, compact butterfly valves clamped between two flanges.
Details →Our Lug Type Butterfly Valves
ORFA supplies lug type butterfly valves in a range of pressure classes, sizes and connection types to suit your application. Descriptions, technical specifications, materials and dimension tables are available on each detail page.
Stainless Steel Disc Lug Butterfly Valve
Stainless steel disc lug butterfly valve: cast iron body, AISI 316 disc, EPDM seat (NBR/Viton option), DN25–DN600, PN16/PN10, max +130 °C, TS EN 593.
Details →Nickel-Plated Disc Lug Butterfly Valve
Nickel-plated lug butterfly valve: GG-25 body, nickel-plated ductile iron disc, EPDM seat, DN25–DN600, PN16/PN10, max +130 °C, TS EN 593. Economic water valve.
Details →PTFE-Sealed Lug Butterfly Valve
PTFE-sealed lug butterfly valve: cast iron body, AISI 316 disc, PTFE seal, DN50–DN300, PN10, max +110 °C, TS EN 593. For chemical and food lines.
Details →Bronze Disc Lug Butterfly Valve
Bronze disc lug butterfly valve: ductile iron body, aluminium bronze disc, NBR seal, DN40–DN600, PN16/PN10, max +90 °C, TS EN 593. For seawater and marine piping.
Details →Get a quote for your project
Our sales team will prepare the best solution for your needs.