Internal Mechanical Seals




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In process piping systems, numerous leaks often suggest that large sections of pipe may need to be replaced, although in many cases the deterioration is limited to the pipe joints.  Preferential attack at welded joints is a common problem and deteriorated conditions can also be found at flanged and bell and spigot connections.  Typically, repairs range from complete replacement of the affected area to welded patches and belly bands.  The use of internal mechanical seals to arrest leakage is a method that is new to power plants and industrial facilities, but has been in use for over twenty years by municipalities.  This relatively simple method to repair and isolate deteriorated areas is currently limited to piping diameters 16 inches and larger, and requires man entry into the piping.  The rapid installation time of these type seals minimizes system down time and increases overall piping reliability.  As many as 100 seals can be installed, inspected and tested during a 48 hour period.

Internal Mechanical Seals Print our Internal Mechanical Seals Brochure with Adobe®
  • Man Entry Required
  • Typical Diameters 16 inches and Up
  • Hundreds of Thousands Installed
  • Seals Have Been in Use Since Late 1950's
  • 50 Year Design Life

Applications

  • Cooling Water Piping
  • Circulating Water Piping
  • Potable and Non-Potable Piping
  • Sanitary Sewer Piping
  • All other piping with Temperatures <300° F

Physical Characteristics

  • Elastomeric Seal
    • EPDM Rubber
    • Grooves for Retaining Bands
    • Pressure Test Valve
  • Retaining Bands
    • Carbon or Alloy Steel
    • One or Multi Piece Design

Installation of Internal Mechanical Seals        Step 1, Step 2, Step 3 pictures

  • Area(s) of Seal Installation is Cleaned and Filled with Epoxy Grout as Necessary to Fill Significant Voids
  • Rubber Seals are Brought in and Put in Place
  • Retaining Bands Positioned
  • Retaining Bands Hydraulically Expanded
  • Wedges are Installed (various sizes) while Bands are Expanded, to Fill Gap in Band
  • After Minimum 1 Hour wait Bands are Re-expanded to Adjust for Creep of Rubber
  • Finished Seal is Pressure Tested Using Integral Valve Assembly to 10 psi and Checked for Leaks