Butterfly Check Valve

Descripción general del producto

The Large Diameter Butterfly Check Valve is an automatic non‑return valve designed for pipelines with nominal diameters of DN300 and above. Its disc is a circular plate that rotates around a central pin shaft, similar to the disc of a butterfly valve. Compared with traditional swing check valves, the butterfly check valve offers significant advantages such as short face‑to‑face length, light weight, low flow resistance, and smooth closing. It is especially suitable for large‑diameter pipeline systems including municipal water supply and drainage, water diversion projects, power plant circulating water, sewage treatment, and industrial cooling water. This valve features flanged connections, with body materials of ductile iron, carbon steel, or stainless steel. Optional external counterweights and hydraulic damping devices enable two‑stage closing (fast closing plus slow closing), effectively reducing water hammer.

Product Structure

The Large Diameter Butterfly Check Valve mainly consists of the following parts:

1. Body: Cast or fabricated body in ductile iron (QT450‑10), carbon steel (WCB), stainless steel (CF8/CF8M), etc. Flanged ends conforming to GB/T 9113, ANSI B16.5, EN 1092‑1, AWWA C207, etc.

2. Butterfly Disc (Disc): Streamlined circular disc rotating around a central pin shaft. Available in single‑offset, double‑offset, or triple‑offset designs to reduce wear and improve sealing. The disc can be hardfaced or covered with rubber/PTFE.

3. Pin Shaft: Stainless steel or corrosion‑resistant alloy through‑shaft or segmented shaft ensuring smooth disc movement.

4. Seat: Metal seat (hardfaced with Stellite or Co‑base alloy) or soft seat (rubber/PTFE). Triple‑offset design enables zero‑leakage metal sealing.

5. Counterweight (optional): Mounted on an external lever to adjust closing speed and reduce water hammer peaks.

6. Hydraulic Damping Cylinder (optional): Works with the counterweight to provide slow closing at the final stage, further eliminating water hammer.

7. Stop Device: Limits the maximum disc opening to prevent over‑travel.

Short face‑to‑face length (wafer or short flanged design), much lighter than conventional swing check valves of the same size.

Function

1. Prevents Backflow: Forward pressure opens the disc; reverse pressure or flow stoppage makes the disc quickly return to its seat under gravity, backpressure, and auxiliary devices, stopping backflow.

2. Low Flow Resistance: When fully open, the disc is nearly parallel to the flow path, providing a low resistance coefficient and significant energy savings.

3. Water Hammer Reduction (optional): With a counterweight and hydraulic damping cylinder, two‑stage closing can be achieved: fast closing (approx. 80° stroke) followed by slow closing (remaining approx. 10° stroke), greatly reducing water hammer impact.

4. High Sealing Performance: Soft sealing (zero leakage) or triple‑offset metal sealing (zero leakage, high temperature resistance, wear resistance) available.

5. Compact Structure: Length is only 1/3 to 1/5 of conventional swing check valves, saving installation space and reducing pipeline loads.

6. In‑Line Maintenance: Some top‑entry designs allow internal part inspection without removing the valve from the pipeline.

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Working Conditions

1. Applicable Media: Clean water, raw water, seawater, sewage, cooling water, oil, gas, steam, mildly corrosive chemical media, etc.

2. Temperature Range: –29°C to +425°C (metal seated, material dependent); –20°C to +150°C (soft seated).

3. Clase de presión: PN6, PN10, PN16, PN25, PN40 (Class 150, Class 300; higher available on request).

4. Installation Position: Horizontal pipeline (recommended); vertical (flow upward) also acceptable.

5. Typical Applications:

   1. Large municipal water supply pump station discharges

   2. Long‑distance water diversion main pipelines

   3. Power plant circulating cooling water systems

   4. Large wastewater treatment plant lift pump discharges

   5. Steel mill and chemical plant industrial water networks

   6. Seawater intake pump discharges

   7. Fire protection system main headers

Summary

The Large Diameter Butterfly Check Valve, with its outstanding advantages of short face‑to‑face length, lightweight design, low flow resistance, and optional water hammer reduction, is a modern alternative to traditional swing check valves in large‑diameter pipeline systems. For DN300 and above applications such as water supply, drainage, circulating water, and industrial pipelines, the butterfly check valve not only effectively prevents backflow but also, when equipped with a counterweight and hydraulic damping cylinder, achieves two‑stage closing that greatly mitigates water hammer hazards. Its compact structure reduces pipe support requirements and installation costs, while double‑offset or triple‑offset designs ensure long‑term reliable sealing. Whether in large pumping stations or long‑distance water transmission projects, the Large Diameter Butterfly Check Valve is a safe, efficient, and economical core device for backflow prevention.