Wafer Butterfly Valve With Worm Gear Drive

 

Wafer butterfly valve with worm gear drive for easy manual operation of large pipe sizes. Self‑locking gear holds position without a brake. Ideal for water, wastewater, and industrial systems.

 

Item	Specification
Valve Type	Wafer Butterfly Valve with Worm Gear Drive
Operation	Manual Worm Gear (self‑locking)
Nominal Size	DN200 – DN1200
Pressure Rating	PN10 / PN16 / ANSI150
Connection Type	Wafer (between flanges)
Body Material	ASTM A536 / EN GJS‑450 Ductile Iron
Disc Material	SS304 / SS316 / Coated Ductile Iron
Seat Material	EPDM / NBR / FKM / PTFE
Stem Material	SS304 / SS316
Gear Ratio	20:1 to 60:1 (depending on size)
Handwheel Diameter	200mm to 400mm
Handwheel Turns (0° to 90°)	5 to 15 turns (by gear ratio)
Position Indicator	Yes (large dial, 0° to 90°)
Self‑Locking	Yes (worm gear design)
Top Flange	ISO 5211 (for actuator conversion)
Coating	Fusion Bonded Epoxy (250‑300 microns)
Face to Face	ISO 5752 Series 20 (wafer)
Standards	ISO 5752 / EN 593 / API 609

 

 

Worm Gear Makes Large Valves Easy to Turn
A DN500 butterfly valve needs over 80 kg of force at a lever handle. No one can turn that easily. Our worm gear reduces the force by 40 to 1. You turn a small handwheel with very little effort. One finger can operate a DN600 valve.

Self‑Locking Gear Holds Position Without a Brake
The worm gear design locks itself. When you stop turning the handwheel, the valve stays exactly where you left it. No brake needed. No handle strap. The valve will not move even with high flow or pressure surges.

Smooth, Precise Disc Positioning
The gear ratio gives you fine control over disc position. One full turn of the handwheel moves the disc only 9 degrees (for a 40:1 gear). You can adjust flow very precisely. Set the valve at 10%, 30%, 50%, or 75% open.

Clear Position Indicator Shows Disc Angle
The gear operator has a large, easy‑to‑read position indicator. You see at a glance if the valve is open, closed, or partially open. The indicator shows 0° (closed), 90° (open), and every position in between. No guessing.

 

 

Wafer Design Saves Space and Weight
The wafer body fits between two pipe flanges. No extra flanges of its own. For a DN600 valve, the wafer type weighs 195 kg. A flanged type would weigh over 300 kg. Your pipe supports need less strength.

Soft Rubber Seat Gives Zero Leakage
The EPDM seat presses tightly against the disc edge. When you close the valve, the rubber compresses. The seal becomes bubble‑tight. No water passes through. No waste. No customer complaints.

Low Flow Resistance Saves Pumping Energy
When fully open, the disc sits edge‑on to the flow. Water passes around it with very little resistance. The pressure drop is minimal. Your pump works less hard. Your electricity bill goes down each month.

Four Seat Materials Handle Your Media
EPDM for water and mild chemicals. NBR for oils and fuels. FKM (Viton) for high temperatures and aggressive fluids. PTFE for strong acids and food service. Tell us your media. We recommend the right seat.

Corrosion‑Proof Coating Extends Valve Life
We coat every valve body with fusion bonded epoxy. Thickness is 250 to 300 microns. This protects against rust, chemicals, and weather. The valve will outlast the pipes around it.

Easy to Install Between Any Flanges
Center the valve between your flanges. Insert bolts through both flanges and the valve. Tighten in a cross pattern. No gaskets needed. The rubber seat seals directly against the flanges.

Actuator Ready for Future Automation
The top flange follows ISO 5211 standard. Need to automate later? Remove the handwheel. Bolt on a pneumatic or electric actuator. The gear box stays as a manual backup.

Built for Frequent Operation
Lever handles wear out after many cycles. The worm gear is built for thousands of operations. Gears are hardened steel. Bearings are sealed. You get reliable service for many years.

 

 

Water Transmission Mains (DN350 and larger) – Large pipelines need reliable isolation valves. Worm gear makes operation easy. Self‑locking keeps valve in position.

Pump Station Discharge Lines – High pressure and flow at pump outlets. Worm gear holds position against dynamic forces. Operators open and close valves without strain.

Raw Water Intake Lines – Valves at river or lake intakes are often large and hard to reach. Worm gear allows one person to operate from a safe distance.

Wastewater Treatment Plant Aeration Basins – Frequent operation for maintenance cycles. Worm gear handles thousands of cycles without wear. Self‑locking prevents accidental closure.

HVAC Chilled Water Plants – Large buildings have chilled water pipes up to DN800. Worm gear valves give maintenance staff precise control for flow balancing.

Industrial Cooling Towers – Large cooling towers need big isolation valves. Worm gear makes quarterly maintenance easy. Position indicator shows valve status from a distance.

Power Plant Cooling Water – Condenser cooling water lines are often DN1000 or larger. Worm gear operators provide smooth operation. Self‑locking is critical for safety.

Desalination Plants – High pressure and corrosive seawater. Choose SS316 disc and FKM seat. Worm gear gives precise control for membrane cleaning cycles.

Irrigation District Main Lines – Large canals and pipelines need big valves. Worm gear can be operated by anyone. No special strength required.

Fire Protection Loop Isolation – Large fire water loops need sectionalizing valves. Worm gear holds position reliably. Handwheel can be padlocked in open or closed position.

Paper and Pulp Mills – Stock lines up to DN800. Tough conditions need durable valves. Worm gear withstands frequent operation.

Mining Process Water – Abrasive water needs frequent valve maintenance. Worm gear makes opening and closing easy. Replaceable seat extends valve life.

 

 

Media	Recommended Seat	Disc Material	Notes
Fresh water	EPDM	SS304 or coated DI	Standard choice
Raw water	EPDM	SS304	Contains some sediment
Wastewater	EPDM	SS304	Resists sewage chemicals
Sea water	FKM or EPDM	SS316	SS316 required for corrosion
Chilled water	EPDM	SS304	Insulation recommended
Hot water (80°C)	EPDM	SS304	Within EPDM range
Hot water (120°C)	FKM	SS304	High temp option
Air / compressed air	EPDM	Coated DI	Low cost option
Oils / fuels	NBR	SS304	NBR resists oil swell
Mild chemicals	EPDM	SS304	Check compatibility
Aggressive chemicals	FKM or PTFE	SS316	Consult our engineers
Food products	EPDM or PTFE	SS316	Food‑grade materials
Steam (low pressure)	PTFE	SS316	PTFE for low pressure steam

 

 

Component	Standard Material	Properties	Upgrade Option
Body	Ductile Iron ASTM A536 65‑45‑12	450 MPa tensile, 12% elongation	SS316 for corrosive environments
Disc	SS304	Good corrosion resistance for water	SS316 (salt water), Nylon‑coated DI (abrasion)
Seat	EPDM	-20°C to 80°C, excellent for water	NBR, FKM (Viton), PTFE
Stem	SS304	Good strength, corrosion resistant	SS316 for salt water or chemicals
Gear housing	Cast iron (painted)	Strong, impact resistant	Aluminum alloy (lighter)
Gears	Hardened steel	Wear resistant, long life	Stainless steel for food/pharma
Bearings	Sealed ball bearings	Low friction, no maintenance	Bronze sleeve bearings
Handwheel	Ductile iron with plastic grip	Durable, comfortable grip	Stainless steel
Position indicator	Plastic with metal pointer	Clear, easy to read	Stainless steel
Coating	Fusion Bonded Epoxy	250-300 microns, RAL 5005 blue	Custom color, polyurethane

 

 

Padlockable Handwheel – Add a padlock hasp to the handwheel hub. Lock the valve in open, closed, or any position. Essential for fire protection and security applications.

Extended Handwheel Shaft – For valves installed in pits or deep vaults. Shaft extends from the valve up to ground level. Operate the valve without entering the pit. Available in 1m, 2m, or custom lengths.

Chainwheel Operator – For overhead valves or valves in high ceilings. A chain hangs down from the handwheel. Pull the chain to operate the valve. No ladder needed.

Electric Actuator Conversion Kit – Replace the handwheel with an electric actuator. The gear stays in place. Convert from manual to automated without removing the valve from the pipeline.

Pneumatic Actuator Conversion Kit – For hazardous areas where electricity is not allowed. Bolt on a pneumatic actuator. Use plant compressed air to operate.

Limit Switch Box – Mounts on top of the gear operator. Provides open/closed electrical feedback to your control room. Works with SCADA systems.

4‑20mA Position Transmitter – For precise flow control. Transmitter sends the exact disc position (0% to 100%) to your control system.

Stainless Steel Gear Housing – For food, pharmaceutical, and corrosive environments. No paint to chip. Easy to clean. Will not rust.

Spare Seat Kits – Extra EPDM, NBR, FKM, or PTFE seats for future replacement. We recommend one spare per 10 valves.

Spare Gear Set – Gears are hardened steel and last many years. But for critical applications, a spare gear set gives peace of mind.

Flange Bolt Sets – Bolts, nuts, and washers for installing the wafer valve between your flanges. Correct length for wafer type. Grade 8.8 zinc plated.

Lifting Lugs – For large valves (DN500 and above). Lifting lugs bolt to the gear operator. Use a crane or hoist to lift the valve into position.

Insulation Kit – For cold water applications where condensation is a problem. Insulation covers the valve body and gear operator. Prevents dripping and ice formation.

Fire‑Safe Seals – Special seat and seal design for fire‑safe applications. Meets API 607. Keeps valve sealed even after a fire.

 

 

Air‑Tightness Test (ISO 5208 Rate A – Zero Leakage):

Close the valve fully.

Apply 0.6 bar air pressure to one side.

Submerge the valve in water.

Watch for bubbles for 60 seconds.

Result: No bubbles means zero leakage. This is the strictest test for soft‑seated valves.

Hydrostatic Seat Test (High Pressure):

Close the valve fully.

Apply 1.1 times rated pressure with water (PN16 → 17.6 bar).

Hold pressure for 60 seconds.

Measure any water passing through the seat.

Result: Zero leakage allowed. Record result on test certificate.

Hydrostatic Shell Test (Body Strength):

Open the valve partially (to protect the seat from over‑compression).

Fill the body with water.

Apply 1.5 times rated pressure (PN16 → 24 bar).

Hold for 60 seconds.

Result: No water through the body casting, disc, or stem seals.