Tag Archives: elastomeric

Expansion Joint Failure Analysis

Failure Analysis - Rubber Expansion JointsGallagher Fluid Seals recently added the Rubber Expansion Joint Surveys & Failure Analysis white paper to our Resources page. This white paper discusses the importance of inspecting your plant’s expansion joints.  Proper design and maintenance of rubber expansion joints plays a major role in the overall preservation and lifespan of a piping system.

It will also discuss failure analysis of rubber expansion joints and some of the leading causes of joint failure.

Below is an except from the white paper, discussing failure analysis of rubber expansion joints, and what it can tell you about the overall health of your piping system.


Failure Analysis

There are perceptible warning signs when an expansion joint is failing:

  • Arch inversion indicating a system vacuum that has exceeded the joint’s specified expansion value.
  • Cracking at the base of the arch, which indicates the joint has been over-elongated and should be replaced with one of the proper length.
  • Ply separation on the outside of the cover. This is an indication the joint has been subjected to excessive movement.
  • Leakage due to over-expansion, mating flange surface issues, or poor installation practices, especially (but not limited to) bolt tightness.
  • Ballooning of arch, which indicates excessive system pressure.

Continue reading Expansion Joint Failure Analysis

How Important are Expansion Joint Surveys?

Expansion Joint SurveysGallagher Fluid Seals recently added the Rubber Expansion Joint Surveys & Failure Analysis white paper to our Resources page. This white paper discusses the importance of inspecting your plant’s expansion joints.  Proper design and maintenance of rubber expansion joints plays a major role in the overall preservation and lifespan of a piping system.

It will also discuss failure analysis of rubber expansion joints and some of the leading causes of joint failure.

Below is an except from the white paper, discussing design and maintenance of rubber expansion joints, as well as the importance of expansion joint surveys.


Elastomeric expansion joints are fabricated from natural or synthetic rubber and fabric, normally consisting of an inner elastomeric tube fused to a metal-reinforced fabric body and an elastomeric cover. These expansion joints accomodate greater pipe movement and provide greater abrasion resistance than metal expansion joints.

Expansion Joint SurveysThe proper design and maintenance of rubber (or elastomeric) expansion joints plays a major role in the overall preservation and lifespan of a piping system. They absorb movement, relieve system strain due to thermal change, stress, pumping surges, wear, or settling, reduce mechanical noise, compensate for misalignment, and/or eliminate electrolysis between dissimilar metals. Poorly functioning joints can lead to major deterioration of the piping system’s integrity, creating safety and environmental issues in your plant and processes. Visible signs of wear and fatigue – including exterior surface cracking, blistering, deformation and delamination, exposure to metal or fabric reinforcement, ply separation of the cover, rubber deterioration, and leakage – can alert observant users to potential failure.

Continue reading How Important are Expansion Joint Surveys?

Elastomeric Expansion Joint Installation

Expansion Joint Design GuideGallagher recently released its Expansion Joint Design Guide, now available for download on our site.  This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints.  The excerpt below is a section of our Expansion Joint Design Guide focusing on types of elastomeric joint installation, pipe layouts, and joint troubleshooting.  To download the entire guide, visit our Resources Page, or click on the image to the right.


Preparation

Expansion Joint InstallationCheck Service Range
  • Double check expansion joint performance limits against anticipated operating conditions
  • Check temperature, pressure, vacuum recommendations
  • Check total joint deflection—alter as needed to reduce deflection to correct range
  • Anchor lines
Check Location
  • Proper location is usually close to main anchoring point
  • Install pipe guide(s) for proper alignment
  • Joint should absorb pipeline expansion / contraction between fixed anchor points

Continue reading Elastomeric Expansion Joint Installation

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 Continue reading Elastomeric Expansion Joint Components