Name: TANGGONG Industrial Butterfly Valve Series
Brand: TANGGONG VALVE GROUP
Availability: InStock
Rating: 4.8 (36 reviews)

Question 1

What is the difference between wafer and lug butterfly valves?

Accepted Answer

A wafer butterfly valve is designed to be clamped between two pipe flanges — it has no flange mounting holes of its own and relies on the pipeline flange bolts passing around the valve body. It is lighter and more economical but cannot be used for dead-end (end-of-line) service. A lug butterfly valve has threaded inserts (lugs) on the valve body that accept flange bolts, allowing each side of the pipeline to be independently bolted to the valve. This enables downstream pipe removal (dead-end service) while the upstream side remains under pressure — making lug valves essential for isolation downstream of the valve.

Question 2

What is a triple offset butterfly valve?

Accepted Answer

A triple offset butterfly valve incorporates three geometric offsets from the pipe centerline: (1) the shaft axis is offset from the disc center, (2) the shaft axis is offset from the pipe/seat centerline, and (3) the seat cone axis is inclined/offset from the disc face. These three offsets create a conical seating geometry where the disc mates with the seat only at the final point of closure — eliminating rubbing friction and wear between seal surfaces. This enables metal-to-metal zero-leakage performance with torque-seated rather than position-seated closure, making triple offset valves ideal for high-temperature (up to 650°C), cryogenic, fire-safe, and critical zero-leakage applications.

Question 3

What materials are butterfly valve seats available in?

Accepted Answer

TANGGONG butterfly valves are available with multiple seat materials matched to service conditions: PTFE (up to 180°C, excellent chemical resistance for acids and solvents), RTFE (reinforced PTFE up to 200°C, better wear resistance), EPDM (up to 120°C, for water, seawater, and mild chemicals), NBR/Buna-N (up to 80°C, for hydrocarbon and oil services), Viton/FKM (up to 180°C, for aggressive chemicals and high-temperature oils), Metal-to-Metal (up to 650°C, for triple offset and high-temperature high-pressure service), and Inconel/Stellite hard-faced metal seats for severe erosion and high-cycle service. Our engineering team can recommend the optimal seat material for your media, temperature, and pressure conditions.

Question 4

Can butterfly valves be used for throttling?

Accepted Answer

Yes, butterfly valves can be used for throttling (flow regulation) within certain operational limits. The disc position provides progressive flow control from 0° (closed) to approximately 60° open, with most of the flow change occurring between 20° and 70° of disc rotation. However, continuous high-velocity throttling at narrow openings (below 20°) can cause cavitation and vibration in liquid services. For demanding throttling applications, TANGGONG recommends high-performance (double offset) butterfly valves with PTFE/metal seats, which provide better throttling characteristics than standard rubber-seated designs. Triple offset butterfly valves are primarily for on/off isolation and emergency shut-off rather than continuous modulation.

Question 5

What size range do TANGGONG butterfly valves cover?

Accepted Answer

TANGGONG manufactures butterfly valves from DN40 (1½") to DN3000 (120") in nominal diameter. Standard sizes DN50–DN1200 are typically available from our in-stock inventory. Wafer and lug types cover DN50–DN1200, flanged butterfly valves from DN80–DN3000, high-performance (double offset) from DN50–DN1200, and triple offset from DN80–DN2000. Pressure ratings range from Class 150 to Class 600. Custom intermediate sizes and non-standard diameters can be manufactured to order. Contact our sales team with your specific size requirement for availability and lead time.

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