Double Acting Pneumatic Lug Butterfly Valves
A double acting pneumatic lug butterfly valve brings together a springless actuator driven by air in both directions and a threaded lug body. Even if one flange is removed, the automated valve stays attached to the other flange through its lugs and can keep that side of the line closed.
Without spring force, the actuator moves directly and with full torque in the direction air is applied; when air is lost, the valve keeps its position. The valves in this group come with grey iron bodies and stainless or nickel-plated discs in DN25–DN300, PN16.
Main Applications
- Automated tank outlets and filling stations
- Sequenced start-up valves in pump banks
- Automated filter lines with one side taken out for maintenance
- Ballast and service water lines on ships
- Non-chemical process water distribution headers
- Remote-controlled end-of-line isolation points
Technical Data
| Valve connection | Lug; threaded lugs, separate bolts per flange |
|---|---|
| Size range | DN25–DN300, depending on model |
| Valve pressure class | PN16 |
| Lug threads (PN16) | DN25: 4×M12 · DN50: 4×M16 · DN100: 8×M16 |
| Medium temperature | EPDM −10 / +130 °C |
| Actuator | Rack and pinion, double acting, springless |
| On air loss | Stays in last position |
| Supply pressure | Depending on model (manufacturer torque table) |
| Valve operating torque (10 bar) | DN50: 15 Nm · DN100: 48 Nm · DN150: 106 Nm · DN300: 410 Nm |
| Solenoid | NAMUR type directional valve, 220 V or 24 V DC, lockable manual override screw |
| Limit switch | IP67, 2 mechanical or inductive switches, 0–90° indicator |
| End-of-line use | Possible; permissible pressure depending on model |
Material Options
| Part | PN16 · GG25 body, stainless disc | PN16 · GG25 body, nickel-plated disc |
|---|---|---|
| Valve body | Grey cast iron GG25, threaded lugs | Grey cast iron GG25, threaded lugs |
| Disc | Stainless steel AISI 316 | Nickel-plated ductile iron GGG-40.3 |
| Valve stem | SS420 (DN25–300) | SS420 (DN25–300) |
| Seat / liner | EPDM | EPDM |
| Limit switch shaft and bolts | AISI 316 stainless steel | AISI 316 stainless steel |
| Limit switch seal | EPDM | EPDM |
| Indicator | Transparent plastic | Transparent plastic |
The stainless disc type is used in chlorinated and mildly corrosive water, the nickel-plated disc type in closed heating and cooling water. If the line must close by itself on air failure, choose the single acting (spring return) lug type.
Advantages
Automation + Easy Removal
- One side can be removed independently thanks to the lug body.
- Maintenance without taking out the automated valve.
Full Torque in Both Directions
- Movement is not made against a spring.
- Reliable closing on high-friction liners.
Local Manual Operation
- Lockable manual screw on the solenoid.
- Commissioning and testing without power.
Single Cable Connection
- The solenoid can be wired inside the box.
- One cable for both switch box and valve.
Construction and Design Features
- Threaded lug valve body with elastomer liner
- Springless double acting pneumatic actuator
- NAMUR type directional valve mounted directly on the actuator
- Limit switch box with 3D open-closed indicator
- ISO 5211 actuator connection
Request a quote for double acting pneumatic lug butterfly valves by stating size, end-of-line use, air pressure, solenoid voltage and feedback needs.
How to Choose?
- Choose the bodyChoose the lug body if one side of the automated valve will be removed separately or the valve sits at a line end.
- Check the outage scenarioA double acting type suits cases where the valve may stay in place when air is lost.
- Verify actuator torqueCompare the valve torque at 10 or 16 bar with the actuator torque at the lowest air pressure.
- Plan the control connectionChoose the solenoid voltage; specify the limit switch box and cable entry for the PLC.
Complementary Products
Why ORFA?
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Single Acting Pneumatic Lug Butterfly Valves
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Details →Our Double Acting Pneumatic Lug Butterfly Valves
ORFA supplies double acting pneumatic lug 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.
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