DEMCO Series DR Double-Acting Pneumatic Actuator for Butterfly Valves, 2″–24″

The DEMCO Series DR double-acting pneumatic actuator is the most economical Series-DR variant: two opposed pistons with integral gear racks coupled to a common central drive shaft, requiring either air or hydraulic pressure on either side of the pistons to open or close the valve (fail-last-position). The body, pistons and end caps are aluminium; the central drive shaft is hard-anodised Aluminium Alloy 70-75. Carbon-filled Teflon guide bands support the pistons to eliminate metal-to-metal contact during operation, so piston O-rings are dedicated to sealing rather than bearing duty. Mounting is direct via a splined aluminium stem adapter on the 2″–12″ valves (NE-C/NE-I/NE-D) and via a keyed stem on the 14″–24″ NF-C valves. Available in 10 frame sizes — EDA40 through PDA4000.

What it does

Converts pneumatic (air) or hydraulic supply pressure into a 90° rotary stroke that opens or closes the valve under remote command. Double-acting means pressure is required to move the valve in either direction — fail-last-position behaviour on supply loss.

Compatibility

• Compatible valve series: NE-C, NE-I, NE-D, NF-C (2″–24″ — automated installations)
• Compatible valve sizes: 2″ – 24″ (50 – 600 mm)
• Mounting standard: Direct mount via splined aluminium stem adapter (most popular sizes); aluminium adapter plate (closed-coupled) for non-direct sizes; steel brackets and coupling kit for the largest valves

Configuration & trim

Specify the valve series and size you intend to mount the actuator on, the supply medium (air or hydraulic), the available supply pressure (40, 60, 80, 100, or 120 psi), and the orientation (flow-axis closed/open relative to the actuator body). Indus Hydraulics will size the actuator against the valve's wet-opening torque table and confirm the right model — the part number suffix encodes valve size, orientation and accessories.

• Actuation method: Double-acting opposed-piston pneumatic actuator with integral gear racks (rotary motion)
• Trim options: Aluminium body, pistons and end caps; hard-anodised Aluminium Alloy 70-75 central drive shaft; plated-steel fasteners; Buna-N seals; carbon-filled Teflon guide bands; flatted stem adapter (2″–12″) or keyed stem (14″–24″)
• Maximum torque output: EDA40: 620 in-lb @ 120 psi · EDA200: 3,071 in-lb · EDA350: 5,337 in-lb · EDA600: 9,069 in-lb · EDA950: 13,537 in-lb · EDA1600: 22,379 in-lb · PDA2500: 35,912 in-lb · PDA4000: 60,623 in-lb
• Supply / input pressure range: 40 – 120 psi air or hydraulic
• Weatherproofing / environmental: Totally enclosed with gaskets — weatherproof body construction (NEMA 4 / NEMA 7 enclosures available for accessories)

Engineered features

• Two opposed pistons with integral gear racks — high torque in a compact envelope
• Hard-anodised Aluminium Alloy 70-75 central drive shaft
• Carbon-filled Teflon guide bands eliminate metal-to-metal contact
• Buna-N seals; totally enclosed with gaskets — weatherproof
• Flatted-stem direct-mount on 2″–12″; keyed-stem mount on 14″–24″
• Fail-last-position — pressure on either side opens or closes the valve
• 10 frame sizes covering 204 in-lb to 60,623 in-lb torque output
• Compatible with DEMCO solenoid valves, position-indicator switches, pneumatic positioners and exhaust metering valves (sold separately)

Typical applications

• Automated process-plant isolation valves
• Cooling-water and chilled-water automation
• Tank-farm batch-control valves
• Pump-discharge automation
• CIP / SIP automated isolation (sanitary services — pair with a sanitary valve)
• Power-plant condenser and feed-water automation

How to order

For your RFQ, please specify: the DEMCO valve series and size you intend to mount this accessory on, the trim level required (standard, corrosion-resistant or sanitary where applicable), and any environmental requirements (chemical exposure, temperature, IP rating). Indus Hydraulics will return an estimate against the corresponding DEMCO base part number.

Example DEMCO base part numbers in this product family:

• J024872-01 (EDA40)
• J024872-02 (EDA65)
• J024872-03 (EDA100)
• J024872-04 (EDA200)
• J024872-05 (EDA350)
• J024872-08 (PDA1100)
• J024872-10 (PDA4000)

Companion products

This accessory is part of the DEMCO butterfly-valve product family. See the matching valve series in IH-VAL-BFLY-NEC, IH-VAL-BFLY-NEI, IH-VAL-BFLY-NEI-SAN, IH-VAL-BFLY-NED, IH-VAL-BFLY-NEIT and IH-VAL-BFLY-NFC.