DEMCO Worm-Gear Operator for Butterfly Valves, 2″–36″

The DEMCO weatherproof worm-gear operator is the standard manual operator for 8″ and larger DEMCO butterfly valves and is recommended on every NF-C (14″–36″) installation. The gray-iron case and cover enclose a ductile-iron gear and hardened-steel worm supported on bronze bearings, with the gearing permanently lubricated for the life of the valve. Self-locking in all positions — adjustment screws stop travel at the open and closed positions, and a position indicator is standard on every model. Available with handwheel, chain-wheel, square-nut, or crank input. Standard external coating is green enamel; white epoxy, coal-tar epoxy and inorganic-zinc primer are available on special order for offshore or buried-service applications.

What it does

Reduces operator input torque by 30:1 to 316:1 — converting a manageable hand-wheel input into the high stem torque required to operate large butterfly valves. Self-locking action holds the valve in any position without back-drive.

Compatibility

• Compatible valve series: NE-C, NE-I, NE-I Sanitary, NE-D, NEI-T, NF-C (full DEMCO butterfly-valve range)
• Compatible valve sizes: 2″ – 36″ (50 – 900 mm)
• Mounting standard: DEMCO top-flange standard — direct mount on 2″–24″; large-bore mounting kit on 30″–36″

Configuration & trim

Specify the valve series and size you intend to mount the gear operator on (DEMCO selects the right gear ratio automatically), the input style (handwheel, chain-wheel, square-nut, crank), and the chain length in feet for chain-wheel input (suffix = length, e.g. 4462-025 for 25 ft of chain). Chains are ordered separately. For chain-wheel installations, mount the valve upside-down to ensure pipe clearance and visual contact with the position indicator.

• Actuation method: Manual hand-operated worm-gear with self-locking action
• Trim options: Gray-iron weatherproof case with ductile-iron gear and hardened-steel worm; bronze bearings; green-enamel exterior (white epoxy / coal-tar epoxy / inorganic-zinc primer available special order)
• Maximum torque output: 46 ft-lb input → 30:1 ratio (2″–6″); 65 ft-lb → 48:1 (8″–16″); 98 ft-lb → 57:1 (18″–20″); 164 ft-lb → 60:1 (24″); 104 ft-lb → 316:1 (30″); 174 ft-lb → 240:1 (36″)
• Supply / input pressure range: N/A (manual)
• Weatherproofing / environmental: Gray-iron weatherproof case and cover; permanently lubricated; position indicator standard on every model

Engineered features

• Self-locking in every position — manual operators cannot back-drive under flow forces
• Gray-iron weatherproof case and cover
• Ductile-iron gear and hardened-steel worm with bronze bearings
• Permanently lubricated for valve life
• Position indicator standard on every model
• Travel stops adjust to set open and closed positions
• Optional adjustable memory stop for "balance return" to a preset open position after closing
• Four input options: handwheel, chain-wheel, square-nut, crank
• Five gear ratios across 2″–36″ — 30:1, 48:1, 57:1, 60:1, 240:1, 316:1
• Special-order coatings: white epoxy, coal-tar epoxy, inorganic-zinc primer

Typical applications

• 8″ and larger DEMCO butterfly-valve installations (where manual lever is not practical)
• Power-plant cooling-water and condenser-water mains
• Water- and waste-water treatment
• Mining tailings and concentrate handling
• Marine ballast and bilge mains
• Buried-service installations (square-nut or chain-wheel input + special-order coating)

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:

• 22622 (2″–6″, handwheel)
• 22623 (8″–12″, handwheel)
• 2060229 (14″, gear-op assy)
• 2060231 (18″–20″, gear-op assy)
• 2060332 (30″, gear-op assy)
• 2060334 (36″, gear-op assy)

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.