Long Weld Neck Orifice Metering Flange with Raised Face

The Long Weld Neck Orifice Metering Flange with Raised Face is designed for precise flow measurement in oil, gas, chemical and process piping systems. Featuring an extended weld neck hub and a machined raised face with pressure tap holes, this specialty flange accommodates an orifice plate or flow meter to deliver accurate differential pressure readings for custody transfer and process control applications.

Manufactured to ASME B16.36 dimensional standards, each long weld neck orifice flange is forged from carbon steel or stainless steel to provide the structural rigidity required for stable, repeatable measurement. The elongated hub allows for easier welding and inspection while maintaining alignment of the pressure taps, ensuring the orifice plate is seated accurately for reliable flow data.

Product Specifications

Key Advantages

• Extended weld neck hub for easy welding and inspection
• Precision machined pressure tap holes for accurate flow readings
• Raised face sealing surface for reliable gasket performance
• Forged construction ensures dimensional stability
• Conforms to ASME B16.36 metering flange standards
• Available in carbon steel and stainless steel materials
• Suitable for custody transfer and process control applications
• Custom tap orientation and orifice plate compatibility

Frequently Asked Questions

Q: What is a long weld neck orifice flange used for?

A: A long weld neck orifice flange is used to mount an orifice plate for flow measurement. The pressure taps in the flange body connect to a differential pressure transmitter, allowing operators to calculate flow rate from the pressure drop across the orifice plate.

Q: What is the difference between a weld neck flange and a long weld neck flange?

A: A long weld neck flange has an extended hub compared to a standard weld neck flange. This longer hub provides additional reinforcement, improves accessibility for welding, and is commonly specified for orifice metering applications where extra rigidity and stable pressure tap alignment are required.

Q: Which standard governs orifice metering flanges?

A: Orifice flanges are manufactured to ASME B16.36, which defines dimensions, tolerances and pressure tap locations. For European projects, equivalent EN standards may apply, and our team can support both specifications.

Manufacturing & Quality Control

Long weld neck orifice flanges are machined from forged blanks with close attention to pressure tap location and bore concentricity, since these directly affect flow measurement accuracy. Each flange is inspected to verify tap hole alignment, raised face finish and hub dimensions against ASME B16.36. We also provide material test certificates and, on request, dimensional reports for custody transfer applications.

Q: How accurate is flow measurement with an orifice flange?

A: Flow measurement accuracy depends on the orifice plate, pressure tap alignment and transmitter calibration. Our long weld neck orifice flanges are machined to tight tolerances for stable, repeatable pressure readings, supporting measurement uncertainty of around one to two percent in well-maintained metering systems.