DEMCO Series DR Spring-Return Pneumatic Actuator for Butterfly Valves, 2″–24″

The DEMCO Series DR spring-return pneumatic actuator uses compression spring(s) to move the valve in one direction, with air pressure moving it in the opposite direction. On loss of supply air, the spring drives the valve to a predetermined safe position — fail-open or fail-closed depending on the spring orientation. The standard choice for safety-critical automated valve installations: emergency shutdown valves, blow-down lines, fire-water valves, and any application where loss of control air must drive the valve to a defined position. Six spring-set arrangements (sets 2–6 on ESA40–ESA1600; sets 8–14 on PSA2500–PSA4004) tune the spring torque to the application, with declutchable manual override available across the full range.

What it does

Converts pneumatic supply pressure into a 90° rotary stroke against a calibrated compression spring. On loss of supply air, the spring drives the valve to a predetermined safe position (fail-open or fail-closed) — ensuring the valve fails to a defined state under any control-system fault.

Compatibility

• Compatible valve series: NE-C, NE-I, NE-D, NF-C (2″–24″ — automated fail-safe installations)
• Compatible valve sizes: 2″ – 24″ (50 – 600 mm)
• Mounting standard: Same as Series DR double-acting — direct splined-stem mount (2″–12″) or keyed stem (14″–24″)

Configuration & trim

Specify the valve series and size, the available supply pressure (40, 60, 80, 100, 120 psi), the desired fail position (fail-open or fail-closed), and the spring set (#2–#6 for ESA series; #8–#14 for PSA series — Indus Hydraulics will recommend the spring set against your wet-opening torque). Optionally specify a declutchable manual override and any required NEMA-7 explosion-proof solenoid or position switch.

• Actuation method: Spring-return opposed-piston pneumatic actuator (fail-open or fail-closed on supply loss)
• Trim options: Aluminium body, pistons and end caps; hard-anodised drive shaft; compression spring(s) sized to the application; plated-steel fasteners; Buna-N seals; declutchable manual override available on size 40 → 4004
• Maximum torque output: ESA40 spring-set 5: 322 in-lb @ 120 psi · ESA350: 4,141 in-lb · ESA600: 8,364 in-lb · ESA950: 12,518 in-lb · ESA1600: 20,668 in-lb · PSA2500: 28,401 in-lb (14-spring set) · PSA4000: 47,613 in-lb (12-spring set) · PSA4004: 47,613 in-lb
• Supply / input pressure range: 40 – 120 psi air
• Weatherproofing / environmental: Totally enclosed with gaskets; declutchable manual override option allows the handwheel to hold the valve in its last position until the actuator returns to automatic

Engineered features

• Compression-spring fail-safe on loss of supply air
• Six spring-set arrangements — tune spring torque to the application
• Spring-Set #2 (mid-spring only) → Spring-Set #6 (full spring stack)
• Declutchable manual override — handwheel engages to hold valve in last position when actuator returns to automatic
• Same aluminium-body construction as the double-acting DR series
• Same Carbon-filled Teflon guide bands and Buna-N seals
• Totally enclosed with gaskets — weatherproof
• Frame sizes ESA40 → PSA4004 covering 322 in-lb to 47,613 in-lb torque
• Compatible with DEMCO solenoid valves, position-indicator switches, pneumatic positioners and speed-control valves

Typical applications

• Emergency shutdown (ESD) automated isolation
• Fire-water and deluge-system valves
• Blow-down and depressurisation valves
• Process safety automated isolation
• Tank-farm fail-safe block valves
• Compressor station fail-safe isolation

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:

• J024873-5-01 (ESA40, spring-set 5)
• J024873-5-04 (ESA200, spring-set 5)
• J024873-5-05 (ESA350, spring-set 5)
• J024873-5-26 (ESA600, spring-set 5)
• J024873-7-09 (PSA2500, spring-set 14)
• J024873-7-11 (PSA4004, spring-set 14)

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.