Which statement best describes an Orifice flange?

• A. They have no center hole and are used to shut off piping.
• B. The OD of the flange is compatible with a larger flange size.
• C. They come as a two flange set connected with standard bolting and two long jackscrews.
• D. They are bored slightly larger than the OD of the pipe.

Answer: (C)

The statement that best describes an Orifice flange is that they come as a two-flange set connected with standard bolting and two long jackscrews. This design is fundamental to the functionality of Orifice flanges, which are specifically used for measuring the flow rate of fluid through a piping system. The two-flange set is critical because it allows the installation of a primary flow device, known as an orifice plate, in between the flanges. The use of jackscrews helps to secure the flanges and the orifice plate in place without needing to disassemble the entire piping system, facilitating maintenance and inspection.

These flanges play a vital role in flow measurement applications and are engineered to create a specific pressure drop across the orifice plate, enabling accurate calculations of flow rates. Their design is integral for ensuring that the orifice plate can be easily replaced or maintained while maintaining the precision needed in hydraulic and pneumatic systems.

In contrast, other descriptions do not accurately characterize Orifice flanges. For instance, the absence of a center hole suggests a function unrelated to flow measurement, while compatibility with a larger flange size or a statement about bore size does not reflect the specific purpose and assembly features unique to these types of flanges. This