What's the difference between butterfly valve and ball valve?

Butterfly valves and ball valves are two mainstream quarter-turn shut-off and flow control valves widely used in fluid pipelines, but they differ dramatically in internal structure, sealing performance, flow capacity, pressure loss, applicable media, cost and installation space. Selecting the wrong type will lead to high energy consumption, frequent leakage or premature equipment failure (Hughes, 2021).

1. Internal Structure & Opening Mechanism

A butterfly valve relies on a thin circular disc rotating 90 degrees around a central shaft to block or open the pipeline flow path. The disc always occupies part of the pipe cross-section even when fully open. Its simple body structure features a compact wafer or lug connection design with minimal overall length.

A ball valve uses a hollow perforated spherical ball as the closure component. When fully opened, the through-hole of the ball aligns completely with the pipeline, forming an unobstructed straight flow channel. Ball valves require thicker, longer valve bodies to accommodate the ball sphere, resulting in larger installation dimensions.

2. Flow Resistance & Flow Coefficient

Butterfly valves generate obvious pressure loss because the disc protrudes into the flow path. They are not ideal for long-distance main pipelines that demand low energy consumption.

Full-port ball valves deliver nearly zero flow resistance and high flow capacity, suitable for large-volume fluid transmission systems where pressure drop must be controlled strictly. Reduced-bore ball valves have higher resistance but still outperform butterfly valves under the same diameter.

3. Sealing Performance & Service Life

Soft-seal butterfly valves achieve bubble-tight sealing under low to medium pressure, yet rubber liners are vulnerable to abrasion from solid particles, high temperature and chemical corrosion. Hard-seal butterfly valves allow minor leakage and require large operating torque.

Soft-seat ball valves maintain reliable zero leakage for a long time. The spherical sealing contact surface bears uniform pressure, resisting scratch damage better than butterfly valve rubber liners. Metal-seated ball valves can also adapt to high-temperature and high-pressure harsh conditions with stable tightness.

4. Working Pressure & Temperature Range

Most standard butterfly valves are rated PN10/PN16; triple offset hard-seal versions can reach PN40 or Class 600. Soft-seal butterfly valves only operate within -20℃ to 120℃.

Ball valves cover wider pressure grades from PN16 up to PN160, and special high-temperature alloy ball valves can work steadily above 500℃. They fit both low-pressure civil pipelines and high-pressure industrial process lines.

5. Application Scenarios & Medium Adaptability

Butterfly valves excel in large-diameter, space-limited pipelines: municipal sewage, HVAC water circulation, ventilation flue gas and low-cost general water supply. They are cost-effective for DN200 and above large pipe sizes.

Ball valves dominate small and medium-diameter pipelines with high tightness requirements: natural gas, chemical oil, pure water, flammable and toxic fluids. They are preferred for small branch pipes requiring frequent full open/close operations.

6. Cost, Weight & Maintenance

Butterfly valves are lighter and much cheaper for large diameters, with simple disassembly and seal replacement.

Ball valves have higher raw material and machining costs, especially in large sizes, and ball cavity dirt accumulation makes on-site maintenance more complicated.

Selection Summary

Choose butterfly valves for large-diameter, low-cost, space-restricted water, sewage and low-temperature gas pipelines. Pick ball valves for small-medium diameter pipelines demanding low pressure loss, zero leakage and stable performance under complex pressure and media conditions.

1. APA 7th Edition

Hughes, S. (2021). Comparative performance analysis of butterfly valves and floating ball valves in industrial fluid control. Journal of Fluids Engineering, 143(10), 101203. 

2. MLA 9th Edition

Hughes, Steven. "Comparative Performance Analysis of Butterfly Valves and Floating Ball Valves in Industrial Fluid Control." Journal of Fluids Engineering, vol. 143, no. 10, 2021, p. 101203, 

3. GB/T 7714-2015

[1] Hughes S. Comparative performance analysis of butterfly valves and floating ball valves in industrial fluid control[J]. Journal of Fluids Engineering, 2021, 143(10): 101203.