High-Precision Flow Measurement Using Orifice Flange Union

Release time：2026-03-05    Click：7

　　In oil & gas, chemical processing, and power generation, the orifice flange union serves as the cornerstone of differential pressure (DP) flow metering—providing a leak-tight, standardized interface for inserting orifice plates that modulate fluid velocity to calculate volumetric or mass flow rates with exceptional repeatability.

　　Designed per ASME B16.36 or ISO 5167, an orifice flange union consists of two matched flanges with concentric tappings (typically at 1D upstream and 0.5D downstream) connected by bolts, creating a cavity for the orifice plate. Materials range from carbon steel (A105) to stainless (316/316L) or duplex alloys for sour service. The orifice bore diameter is precisely calculated based on fluid properties, pipe size, and expected flow range.

　　Key advantages include ease of maintenance—plates can be swapped without cutting pipe—and compatibility with smart DP transmitters for real-time monitoring. The union design eliminates gasket interference with flow streamlines, ensuring accurate beta ratio (d/D) and minimizing turbulence. Calibration traceable to NIST standards guarantees ±0.5% accuracy in ideal conditions.

　　Installation demands strict alignment: pipe straightness (10D upstream, 5D downstream), tapping cleanliness, and plate orientation (bevel downstream for liquids). Thermal expansion must be accommodated with expansion loops in high-temp lines. Regular inspection for erosion or deposits on the orifice edge is critical—microscopic wear alters discharge coefficients.

　　In conclusion, the orifice flange union is a marriage of simplicity and precision. It turns Bernoulli’s principle into actionable data—enabling efficient resource management, custody transfer, and process optimization across heavy industries.

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