Double Acting Pneumatic Wafer Butterfly Valves
In a double acting pneumatic wafer butterfly valve, the actuator makes both the opening and closing movement with compressed air: air supplied to one side of the pistons opens the valve, air to the other side closes it. With no springs, a higher torque is obtained from the same body size and the actuator stays more compact.
When the air supply is lost, the valve stays in its last position, which suits frequently cycled automation lines that do not need a safe position. The wafer-bodied valves come in DN25–DN300, in PN16 or PN10 depending on body and disc type.
Main Applications
- High-cycle isolation on filling and emptying machines
- Automatic backwash sequences in filter and treatment units
- PLC-controlled diversion in cooling and heating circuits
- Programmed open-close on process water and CIP lines
- Isolation on powder, granule and air conveying lines
- Automatic start-up in pumping stations
Technical Data
| Valve connection | Wafer |
|---|---|
| Size range | DN25–DN300 |
| Valve pressure class | PN16 (GG25 and ductile iron body) · PN10 (cast iron body) |
| Medium temperature | EPDM −10 / +130 °C · NBR and PTFE −10 / +80 °C |
| Actuator type | Rack and pinion, double acting (no springs) |
| On air loss | Valve stays in last position |
| Supply pressure | Per manufacturer torque table, depending on model |
| Valve operating torque (16 bar) | DN50: 16 Nm · DN100: 53 Nm · DN200: 194 Nm · DN300: 595 Nm |
| Pilot valve | 5/2-way NAMUR solenoid valve, 220 V or 24 V DC |
| Position feedback | Limit switch box, IP67, 2 mechanical or inductive switches |
| Limit switch working temperature | −20 / +80 °C |
| Valve installation | Stem horizontal or vertical; horizontal recommended for DN300 |
Material Options
| Part | PN10 · cast iron body, stainless disc | PN16 · GG25 body, nickel-plated disc | PN16 · ductile iron body, bronze disc |
|---|---|---|---|
| Valve body | Cast iron | Grey cast iron GG25 | Ductile iron EN-GJS-400-18 |
| Disc | Stainless steel AISI 316 | Nickel-plated ductile iron GGG-40.3 | Aluminium bronze |
| Stem | SS420 | SS420 (DN25–300) | SS420 (DN40–300) |
| Seat / liner | PTFE (−10 / +80 °C) | EPDM (−10 / +130 °C) | NBR (−10 / +80 °C) |
| Actuator | Aluminium body, depending on model | Aluminium body, depending on model | Aluminium body, depending on model |
| Limit switch housing | Oven epoxy-coated aluminium die-cast | Oven epoxy-coated aluminium die-cast | Oven epoxy-coated aluminium die-cast |
The double acting actuator is sized so that, at the lowest plant air pressure, it covers the valve torque at maximum working pressure with a safety margin. If the valve must close by itself on power or air failure, use the single acting (spring return) type.
Advantages
High Torque, Small Body
- No spring force to overcome.
- The same torque is reached with a smaller actuator.
Suited to High Cycling
- Controlled air movement in both directions.
- Repeatable operation in programmed sequences.
Position Retained
- The valve stays put when air is lost.
- Process balance is not upset by a sudden outage.
Standard Accessories
- NAMUR solenoid and limit switch.
- Easy integration into the control system.
Construction and Design Features
- Wafer butterfly valve with liner
- Springless double acting rack-and-pinion pneumatic actuator
- Mounting face for 5/2-way NAMUR solenoid valve
- Optional limit switch box with 3D position indicator
- ISO 5211 connection between valve stem and actuator
Request a quote for double acting pneumatic wafer butterfly valves by stating size, medium, plant air pressure, solenoid voltage and position feedback needs.
How to Choose?
- Assess failure behaviourA double acting type suits applications where the valve may stay in its last position when air is lost.
- Measure the air pressureBase actuator selection on the lowest plant supply air pressure.
- Choose the solenoidA 5/2-way NAMUR solenoid valve for double acting actuators; select voltage to match the control panel.
- Add feedbackAdd a limit switch box with mechanical or inductive switches if open-closed signals are needed in the PLC.
Complementary Products
Why ORFA?
Other Butterfly Valves
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Electric Actuated Wafer Butterfly Valves
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Lug Type Butterfly Valves
Lug type butterfly valves have threaded lugs, so they can be used at line ends and one side can be dismantled.
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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.
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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.
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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.
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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.
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Wafer Type Butterfly Valves
Wafer type butterfly valves are lightweight, compact butterfly valves clamped between two flanges.
Details →Our Double Acting Pneumatic Wafer Butterfly Valves
ORFA supplies double acting pneumatic wafer 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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