The differences between butterfly check valves and swing check valves lie not only in their structural design but also in their typical applications. Although both valve types share the same functions—preventing backflow, enabling light-load pump starting, and reducing water hammer—their design characteristics and operational ranges differ.

Both valve types feature a disc-shaped closure element that rotates around a hinge pin to open or close the valve.

Difference 1: Design Standards

● Butterfly check valves:

CJ/T 282-2008: Butterfly slow-closing check valve

JB/T 5299-2022: Hydraulic control butterfly check valve

● Swing check valves:

GB/T 12236-2008: Steel swing check valves for petroleum, chemical, and related industries

GB/T 13932-2016: Cast iron swing check valves

API 6D and API 594 design standards also apply

Difference 2: Product Structure

In butterfly check valves, the hinge pin passes through the center of the disc and is located inside the flow path.

In swing check valves, the hinge pin passes through the outer edge of the disc sealing surface and is located outside the flow path.

This is the primary structural difference between the two valve types.

Difference 3: Applications of Slow-Closing Design

● Butterfly check valves, like standard butterfly valves, are mainly used in low-pressure, large-diameter pipelines, with nominal diameters up to DN5000. The disc has high inertia, and the fluid exerts significant impact on the disc. Therefore, slow-closing designs are commonly adopted to reduce water hammer. Examples include hydraulic automatic control valves, pipeline force valves, and hydraulic-controlled butterfly check valves.

● Swing check valves are primarily used in medium- and small-diameter pipelines, generally DN15–DN600. Slow-closing designs are less common, though certain models such as HH44X employ this feature.

Difference 4: Application Scenarios

● Butterfly check valves, like standard butterfly valves, are mainly used in low-pressure, large-diameter pipelines, with nominal diameters up to DN5000. The disc has high inertia, and the fluid exerts significant impact on the disc. Therefore, slow-closing designs are commonly adopted to reduce water hammer. Examples include hydraulic automatic control valves, pipeline force valves, and hydraulic-controlled butterfly check valves.

● Swing check valves are primarily used in medium- and small-diameter pipelines, generally DN15–DN600. Slow-closing designs are less common, though certain models such as HH44X employ this feature.

Difference 5: Pipeline Connection Methods

● Butterfly check valves, especially for large-diameter applications, typically use flanged connections, while small-diameter valves may use wafer-style connections.

● Swing check valves offer more diverse connection options, including threaded, flanged, wafer, welded, and clamp connections, providing greater flexibility in installation.