The Laux Valve DN700-DN1200 (28"-48") wafer butterfly valve single flange type is a large-diameter isolation valve engineered for big pumps, tanks, and equipment connections. The body combines an integral flange on one end that bolts directly to a large pump casing, tank nozzle, or equipment outlet, with a wafer face on the opposite end for standard sandwich installation. This hybrid design eliminates adapter spools, reduces system joints, and provides dead-end isolation capability on the flanged side — all in a body that is significantly shorter and lighter than a double-flanged valve of the same size.
It is the ideal choice for large pump suction/discharge lines, water storage tank outlets, municipal water and wastewater facilities, and industrial process equipment where DN700-DN1200 isolation is required but space, weight, and cost matter.
✔ Why Large-Diameter Single Flange Type?
For DN700-DN1200 valves, a double-flanged body adds significant weight and cost. The single flange type keeps one end as a compact wafer face — saving up to 40-50% weight versus double-flange designs — while the integral flange end still delivers direct equipment mounting and dead-end isolation. Fewer joints, shorter length, lower total installed cost.
The single flange type wafer butterfly valve has an asymmetric body: one face is machined as a full integral flange with bolt holes, while the opposite face is a standard wafer face. For large diameters, installation follows two patterns:
| Parameter | Specification |
| Valve Type | Concentric Wafer Butterfly Valve, Single Flange Body |
| Size Range | DN700 – DN1200 (28" – 48") |
| Pressure Rating | PN10 / PN16 / Class 150 |
| Connection (Flange End) | Integral flange, drilled per EN 1092-2 / ASME B16.5 |
| Connection (Wafer End) | Wafer face for sandwich installation |
| Face-to-Face | EN 558 Series 20 short pattern (per size) |
| Body Material | Ductile Iron ASTM A536 65-45-12 (standard); WCB CS (optional) |
| Disc Material | Ductile Iron + Epoxy (standard) / Nylon 11 (option) |
| Stem Material | 416 SS / 420 SS / 316 SS (option) |
| Seat Material | EPDM (standard) / NBR / Hypalon |
| Body Coating | Fusion Bonded Epoxy, min 250 microns |
| Temperature Range | EPDM: -20°C to +90°C | NBR: -10°C to +70°C |
| Leakage Rate | Bubble-tight (ISO 5208 Rate A / Class VI) |
| Operation | Worm Gearbox with Handwheel (standard) / Chain Wheel / Pneumatic / Electric |
| Actuator Mounting | ISO 5211 standard pad (F16/F25/F30 per size) |
| Test Standard | API 598 / EN 12266-1 |
| Item | Single Flange Type | Standard Wafer | Double Flange |
| Equipment Direct Mount | Yes (integral flange) | Needs adapter | Yes |
| Dead-End Service | Yes (flanged side) | No | Yes |
| Weight (DN1000 approx.) | approx. 340 kg | approx. 300 kg | approx. 600+ kg |
| Face-to-Face Length | Compact (wafer-like) | Shortest | Longest |
| Joints in System | Fewer (no adapter) | More (with adapter) | Fewer |
A: It means the valve body has an integral flange on one end and a standard wafer face on the other. The flanged end bolts directly to a pump, tank, or equipment outlet (or a pipe flange), while the wafer end is installed in the conventional sandwich arrangement between flanges.
A: Yes, on the flanged side. Because the flanged end is bolted directly to the equipment or pipe flange, it can hold pressure independently. This makes it suitable for large pump and tank isolation where one side may need to be blanked or opened for maintenance.
A: For DN700-DN1200, a double-flanged body is significantly heavier (often 2x) and more expensive. The single flange type saves 40-50% weight, reduces support steelwork and lifting costs, and shortens the overall installation length — while still offering direct equipment mounting and dead-end isolation on the flanged side.
A: A self-locking worm gearbox with handwheel is standard for all sizes DN700 and above due to the high disc torque. Chain wheel (for overhead installation), pneumatic, or electric actuator options are available via the ISO 5211 mounting pad.
A: No. The rubber liner extends over both faces and serves as the integral gasket on both the flanged and wafer ends. External gaskets are not required for rubber-faced valves.
A: Standard configuration (EPDM seat, epoxy disc, gearbox) is 15-25 working days. PN16 or custom flange drilling may require 25-35 working days. Contact our sales team for current lead times and project pricing.
To order, please specify: size (DN700-DN1200), pressure rating (PN10/PN16), seat material, disc coating, connection drilling (EN 1092-2 / ASME B16.5), operation type (gearbox/chain/pneumatic/electric), and quantity. For equipment mounting, please provide the equipment nozzle flange details.
Email: james@lauxvalve.com | Tel / WhatsApp: +86 18920833829
From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.
