Optimal Applications for Flanged Joints in Industrial Piping an

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  Posted by Julydays December 13, 2023 - Filed in Technology - 235 views
  

  Flanges are a critical component in industrial piping networks, machinery, and processing equipment. Determining the most suitable applications for flanged joints is an important consideration when designing and maintaining these systems. This guide explores optimal uses for ANSI flanges, as well as scenarios where alternative joining methods may be preferable.

  

   

  When to Use Flanges

  Here are common situations where flanged joints are the ideal choice:

  Frequent Disassembly Needed

  Flanges allow quick disconnection for maintenance, cleaning, inspections, part replacements, and reconfigurations. This makes them well-suited for:

  • Piping networks requiring frequent access for inline valves, strainers, instrumentation, etc.
  • Machinery housing rotating assemblies or other internal parts needing occasional replacement.
  • Vessels and tanks need interior access for cleaning and repairs.

  Higher Pressures or Temperatures

  While flanges have lower pressure limits than welded joints, high-strength flanges are designed to handle pressures exceeding 10,000 psi. Flanged joints with quality gaskets can also withstand high temperatures exceeding 700°F. Applications such as:

  • Steam lines
  • Refinery process piping
  • Chemical/petrochemical systems

  often rely on flanges when pressures or temperatures exceed the limits of other joining methods.

  Ability to Isolate Sections

  Installing flanges at strategic locations enables quick isolation of individual line segments, valves, inline components, vessels, and other plant equipment. This facilitates maintenance, flow control, and emergencies. Flanges are ideal for:

  • Long distribution lines need segmented isolation capabilities.
  • Inlet and outlet connections on vessels, reactors, exchangers, etc.
  • Branch lines off main headers.

  Flexibility in Pipe Alignment

  Flanges allow angular misalignment and offset between pipe ends. This flexibility in positioning is advantageous where:

  • Space constraints demand non-linear pipe routing.
  • Shifting foundations causes piping stresses.
  • Connecting pipes with pre-existing misalignment.

  Ability to Mix Components

  Flanges readily join different metals, plastic pipes, valves, and other components. They avoid the limitations of welding dissimilar materials. Applications include:

  • Connecting plastic and metal pipes.
  • Joining stainless equipment to carbon steel piping.
  • Installing inline valves and other components.

  Ease of Repairs/Replacement

  Flange damage can be repaired by simply unbolting and replacing the flange. This avoids the costly replacement of entire pipe sections. Flanges are useful where:

  • Pipe damage risk is higher.
  • Fast repairs are crucial for uptime.

  • Pipe replacement would be labor-intensive.

   

  When to Avoid Flanges

  While flanges have many benefits, they may not be the best choice in these scenarios:

  Extremely High Pressure or Temperature

  Applications exceeding flange pressure/temperature limits may require welded joints or specialized flange materials and gaskets. Flanges are often avoided for:

  • Pressures over 15,000 psi.
  • Continuous temperatures over 700°F.
  • Cyclic services with high combined pressures and temperatures.

  Limited Space Availability

  Flanges require extra space for fasteners and gaskets around the pipe diameter. This may not be feasible where:

  • Piping runs through tightly packed equipment.
  • Machinery must be very compact.
  • Headroom is restricted.

  Permanent Joining is Preferred

  While flanges facilitate disassembly, permanently welded joints may be favored for piping that will rarely if ever require opening. Permanent joints also make sense where:

  • Flange leaks could have catastrophic consequences.
  • Extreme reliability is paramount.
  • Flange maintenance is difficult to perform.

  Excessive Vibration or Movement

  Flange joints can loosen over time when subjected to repetitive pipe movements or vibration. All-welded connections may be needed where:

  • Piping is routed near vibrating equipment.
  • Significant thermal expansion and contraction occur.
  • Pipes convey pulsating flows.

  Key Considerations When Using Flanges

  When flanges are determined to be the optimal choice, follow these guidelines for success:

  • Select reputable China flange manufacturers that adhere to international standards.
  • Choose the correct flange type, size, pressure rating, and materials.
  • Use suitable gasket materials and installation practices.
  • Allow proper bolt sizing, materials, tightening patterns, and torque.
  • Implement robust quality control during fabrication and installation.
  • Establish preventive maintenance programs to ensure longevity.

  By methodically evaluating needs and properly implementing flanged joints, industrial facilities can maximize operational safety, reliability, and productivity.