Industrial-Grade Raised Face Orifice Flange

Release time：2026-02-19    Click：18

　　An industrial-grade raised face orifice flange is a specialized flow measurement component integral to process control systems in oil & gas, petrochemical, power generation, and other heavy industries. It is not a standard flange, but a precision-engineered assembly consisting of a pair of flanges, orifice plate, jack screws, and tapping ports. Its sole purpose is to provide a robust, leak-proof, and standardized method for housing an orifice plate—a primary flow element—within a pipeline to facilitate the accurate measurement of fluid flow rate, pressure drop, and composition via differential pressure (DP) transmitters.

　　The design features are distinct and critical. Each flange in the pair has a raised face with a concentric, machined groove to securely seat the orifice plate. Jack screws are installed between the flanges to allow for easy separation and removal of the orifice plate for inspection or changeout without needing to spread the entire pipeline. The flanges contain precisely drilled and tapped pressure tap holes (corner taps, flange taps, or D&D/2 taps as per standards like ASME/ANSI, ISO, or AGA) that connect to impulse lines running to the DP transmitter. This entire assembly is engineered to withstand high pressures (common ratings include Class 300, 600, 900) and temperatures while maintaining a precise bore alignment.

　　Manufacturing adheres to strict international standards. The flanges are typically forged from carbon steel (A105), stainless steel (A182 F316/F304), or alloy steels, then machined to exacting tolerances. The orifice plate, often made of stainless steel, is precision-machined with a sharp-edged, concentric (or eccentric) bore. The diameter ratio (β ratio) of the bore to the pipe diameter is calculated based on the required flow measurement range. The entire assembly must ensure that the plate is centered perfectly and that the gasket, when compressed, seals effectively around the plate without intruding into the bore.

　　Installation and application require expertise. The orifice flange union is installed in the pipeline at a point with sufficient straight run upstream and downstream (as per standards) to ensure stable, laminar flow for accurate measurement. Proper gasket selection and bolt torqueing are essential to prevent leaks. During operation, the DP transmitter measures the pressure difference created by the constriction of the orifice plate, which is then calculated into flow rate using established equations. This system is favored for its reliability, simplicity, and ability to measure a wide variety of clean gases, liquids, and steam.

　　Specifying an industrial-grade raised face orifice flange is essential for accurate, reliable, and safe flow metering in critical processes. It allows for maintenance without process shutdown, a key advantage. By selecting the correct material class, pressure rating, tap type, and β ratio for the specific service conditions, engineers ensure the integrity of the measurement system, which is fundamental for custody transfer, process efficiency, safety interlocks, and regulatory compliance in high-stakes industrial environments.

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