Elastomeric Expansion Joint Components

From the outside, an elastomeric expansion joint looks to simply be made out of molded rubber.  Part of the reason expansion joints are used in such a wide variety of applications is that the interior construction of a joint can be custom-designed to handle your specific application – materials of construction will depend on size, temperature, application, media, pressure (S.T.A.M.P.).

Layers of Construction

Tube

  • Synthetic or natural rubber forms seamless, leak-proof lining
  • Extends fully through bore to outer flange edge
  • Common materials include chlorobutyl, neoprene, natural rubber, EPDM, Viton* and Hypalon*

Body or Carcass

  • Expansion JointWhen wrapped or plied, reinforcements provide support and flexibility between tube and cover
  • Fabric reinforcement: polyester or other suitable fabrics impregnated with specified elastomers
  • Metal reinforcement: bonded rectangular steel rings [exclusive to Garlock], or continuous strands of wire and round steel body rings
  • Metal reinforcement rings provide longer service life, extra safety protection, and extra rigidity, allowing higher pressure ratings

Expansion Joints - Download your Design Guide

Cover

  • Homogeneous layer of synthetic or natural rubber
  • Chlorobutyl is standard; other elastomers available to meet your specific application
  • Rubber or other weather-resistant coating protects carcass from corrosion or damage

Metal Flow Liners

  • Expansion Joint - Metal Flow LinerMust be used in all applications; provides metal surface to distribute bolting pressure equally, preventing flange damage during bolt tightening
  • Install against external flange surface
  • Standard material: mild steel with corrosion-resistant coating; galvanized or stainless steel also available
  • Extends service life by providing protection from abrasive materials or solids, especially in high velocity applications
  • Flanged at one end, installed at the head of the flow, tapered to a 5° angle, allows lateral deflection
  • Liner flange thickness: 10 gauge | Liner body thickness: 12 gauge
    Available in 304/316 stainless steel; also: titanium, Hastelloy C
    Special metal liner configurations also available for reducing or multiple arch design.

Control Units

  • Expansion Joint - Control UnitRecommended on most applications to prevent damage due to excessive pipe movements
  • Consists of two or more tie rods connected between pipe flanges
  • Triangular end plates (gussets) have two holes for bolting securely to flange, and one hole to accommodate the connecting tie rod
  • Spherical washers are incorporated to accommodate moderate piping alignments, but also assists with angular, torsional and lateral movements
  • Each rod incorporates double nuts on each end to keep the expansion joint from over-elongating
  • When excessive axial compression is a concern, compression nuts can be incorporated to restrict movements as needed and to protect the expansion joint from damage
  • NOT designed to replace pipeline anchoring

Accessories

Fire Resistant Covers

  • Expansion Joint - Fire Resistant CoverRecommended on applications where flammable liquids are being used or in fire water systems.
  • Consists of several layers of fiberglass fabric with a surface cover of silver-colored high temperature resistant silicone aluminum-glass fabric
  • Tested to ISO 1554 at 800˚C for 30 mins for fire resistance
  • Split design which allows for easy installation or inspection
  • Cover is oil resistant and provides added protection against weathering and aging of the expansion joints.

Metal Retaining Rings

  • Expansion Joint - Retaining RingsMust be used in all applications; provides metal surface to distribute bolting pressure equally, preventing flange damage during bolt tightening
  • Install against external flange surface
  • Standard material: mild steel with corrosion-resistant coating; galvanized or stainless steel also available