Expander Flange

on . Posted in Pipe Flange

expander flgExpander flange, abbreviated as EXPF, also called expansion flange, is similar to a weld neck flange but with the hub expanding to a larger size (one or two sizes).  If you have limited space or just need to connect to a larger pipe size, it provides a convenient way for equipment, pumps and valves.  It can replace the use of a flange and reducer.  Pressure ratings and dimensions are in accordance with ANSI/ASME B16.5. This flange has a raised face.

Expander Flange Index

This is a type of flange used in piping systems for connecting pipes of different sizes. It's designed to gradually transition from a larger diameter pipe to a smaller diameter pipe.  The purpose of an expander flange is to allow for a smooth and controlled reduction in pipe diameter while maintaining proper flow characteristics.  Expander flanges have a larger outer diameter (OD) on one end and a smaller OD on the other end.  The larger end is typically welded or bolted to the larger diameter pipe, while the smaller end is connected to the smaller diameter pipe.  This design helps prevent abrupt changes in fluid flow that can lead to turbulence, pressure drops, and other flow related issues.

These flanges are commonly used in systems where a gradual reduction in pipe size is necessary, such as when connecting a larger pipe to a pump or a compressor inlet, or in situations where flow rates need to be controlled or optimized.  Expander flanges come in various sizes and materials to match the requirements of different piping systems and their operating conditions.  Like other flanges, they are designed to be securely bolted to the pipes and provide a leak tight connection.  Proper installation and adherence to industry standards are crucial to ensure the effective functioning of expander flanges within a piping system.

 

Expander Flange Advantages and Disadvantages

AdvantagesDisadvantages
  • Expander flanges are designed to connect pipes of different sizes, providing flexibility in piping systems where variations in pipe diameter are encountered.
  •  The tapered neck of the expander flange allows for a gradual expansion of the pipe diameter, reducing the likelihood of stress concentrations and minimizing the risk of structural issues.
  • Unlike some other types of flanges, the design of expander flanges helps distribute stress more evenly, reducing the potential for localized stress concentrations.
  • The gradual expansion provided by expander flanges contributes to a smooth flow transition, minimizing turbulence and pressure drop in the piping system.
  • Expander flanges can contribute to space and weight savings in certain applications compared to using multiple fittings to connect pipes of different sizes.
  • Installation of expander flanges can be more complex compared to standard flanges.  Proper alignment during installation is crucial to ensure a reliable connection.
  •  Expander flanges may be more expensive than standard flanges or fittings due to their specialized design and the welding process involved.
  • Expander flanges are generally not recommended for high pressure applications.  Their design may not provide the same level of strength as some other flange types.
  • Expander flanges may have limitations in terms of temperature resistance, and they may not be suitable for extreme temperature conditions.
  • The quality of the weld between the expander flange and the pipe is crucial.  Improper welding can lead to issues such as leakage and reduced joint strength.
  • Once welded in place, expander flanges have limited rotation capability.  Proper alignment during installation is crucial to avoid misalignment issues.

 

Expander Flange Datasheets

ClassRaised Face
ANSI 150 Expander, ANSI Class 150 (in)
ANSI 300 Expander, ANSI Class 300 (in)
ANSI 600 Expander, ANSI Class 400 (in)

 

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Tags: Pipe Flange