ASME B16.47 is a standard for large-diameter steel pipeline flanges developed by the American Society of Mechanical Engineers (ASME). The standard divides flanges into Series A (formerly API 605 series) and Series B (formerly MSS SP-44 series), aiming to standardize the design, manufacturing, and application of large-diameter flanges to ensure the safety and compatibility of pipeline systems.
ASME B16.47 Series A Class 150 Blind Flanges are mainly used to close the ends of pipes, block the flow of media, and at the same time facilitate the inspection, maintenance, or subsequent expansion of piping systems.
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Core structure
Flange body: As the load-bearing core, it needs to have sufficient strength to withstand the pressure and external forces of the pipeline system. Its thickness varies according to the nominal size (NPS) to ensure structural stability under Class 150 pressure level.
Bolt holes: evenly distributed along the circumference of the flange, with strict adherence to standard requirements in terms of quantity and diameter. They are used to connect blind flanges with pipeline or equipment flanges through bolts, ensuring tightness and reliability of the connection. The diameter of the center circle of the bolt hole should be accurately matched with the matching flange.
Sealing surface: Common types include raised face (RF), full face (FF), etc. Among them, raised face sealing surface is the most widely used in this specification of blind flange due to its excellent sealing performance and easy installation. The surface roughness and dimensional accuracy of the sealing surface need to meet the standard requirements to ensure effective fit with the gasket.
Comparison with ASME B16.47 Series B
|
Comparison Item |
Series A (Class 150) |
Series B (Class 150) |
|
Nominal Size Range |
Usually covers NPS 26 - NPS 60, mainly large-diameter |
Usually covers NPS 2 - NPS 24, mainly small and medium-diameter |
|
Number of Bolts and Hole Diameter |
For the same NPS, the number of bolts is relatively small, and the hole diameter is relatively large |
For the same NPS, the number of bolts is relatively large, and the hole diameter is relatively small |
|
Flange Thickness |
For the same NPS and pressure rating, the thickness is usually slightly larger, and the structural strength is higher |
The thickness is relatively thin, and the weight is lighter |
|
Application Scenarios |
Large-diameter medium-low pressure piping systems, such as main pipelines of large petrochemical and power projects |
Small and medium-diameter medium-low pressure piping systems, such as industrial equipment connections and municipal branch pipelines |
ASME B16.47 Series A Class 150 Blind Flanges
