Category Archives: Expansion Joints

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.

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NEW Expansion Joint Material – ABRA-SHIELD™

Garlock is excited to announce the launch of ABRA-SHIELD, a new expansion joint material designed for abrasion resistance and sustainability in demanding high temperature operating conditions.

ABRA-SHIELD™As the newest addition to Garlock’s family of abrasion resistant expansion joint materials, ABRA-SHIELD will join ABRA-LINE® and Natural Rubber to provide a variety of liners that cater to increased abrasion protection. ABRA-SHIELD will be an option for use with a number of expansion joint products that Garlock offers – including styles 204, 206, 7250, 8400 and 9394. These expansion joints also provide high levels of protection from stress, misalignment, vibration, noise, shock and corrosion.

In abrasion resistance testing – which provides data to compare materials and predict the lifetime of a material or coating – ABRA-SHIELD provided 50% higher abrasion resistance than standard EPDM (ethylene propylene diene monomer rubber). ABRA-SHIELD will be the recommended solution in abrasive applications (such as slurry, ash and brine) with sustained or spiked temperatures between 180°F and 300°F. For temperatures outside of this range, other materials in Garlock’s family of abrasion resistant expansion joints would be suggested.

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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.

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NEW! Expansion Joint Surveys & Failure Analysis White Paper

Rubber Expansion Joint Surveys & Failure Analysis White PaperGallagher 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.

Download your copy today, and contact our engineering department if you need assistance choosing the right expansion joints for your processes.

When to Use Flue Duct Expansion Joints

Flue Duct - Expansion Joint Design GuideIn July, Gallagher 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 flue duct expansion joints.  To download the entire guide, visit our Resources Page, or click on the image to the right.


Flue Duct Expansion Joints

Used to manage air and gas handling systems, flue duct expansion joints are most widely utilized in the Power Generation, Industrial & Institutional industries:

  • Flue Duct Expansion JointPower Plants
    • Simple Cycle
    • Combined Cycle
    • Co-generation
    • Coal Fired
  • Industrial Operations
    • Steel Mills
    • Paper Mills
    • Cement Plants
  • Institutional Sites
    • Hospitals
    • Schools
    • University Campuses

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Metal Expansion Joints for High Temperature/Pressure

Expansion Joint Design Guide - Metal Expansion JointsGallagher 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 metal expansion joints.  To download the entire guide, visit our Resources Page, or click on the image to the right.


Much like elastomeric expansion joints, metal expansion joints are used to preserve the integrity of a piping system where the piping is subject to changes in temperature, pressure, vibration, compression, extension, cyclical movements or movements required by usage.

Oftentimes, metal expansion joints are used when an elastomeric joint simply cannot handle the extreme conditions – applications where high temperature, large temperature range, or high pressure exists. Generally, metal expansion joints can be used from -450°F to +2000°F, depending on the metallurgy, and can also handle pressures from full vacuum to 3,000psi.

Metal Expansion Joint Components

Though customized and intricate expansion joints can be manufactured for a variety of specialized applications, there are four basic designs that are most commonly used:

Metal Expansion Joints - Basic BellowsBasic Bellows

A bellows can be supplied without end fittings for field installation. The skirt, or straight portion at each end of the bellows, can be sized to fit a flange or pipe. Skirt length can vary depending on your needs and should be specified when ordered.


Metal Expansion Joints - Unrestrained SingleUnrestrained Single

An unrestrained single expansion joint is best used by piping systems which are equipped with proper guides and anchors to absorb axial, angular, and a small amount of lateral movement.

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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

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Elastomeric Expansion Joint Types & Movement

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 joints and types of pipe movement.  To download the entire guide, visit our Resources Page, or click on the image to the right.


The basic purpose of an expansion joint is to absorb movement and vibration in a rigid piping system, being built to expand, contract, and adjust without straining or breaking the piping or ducting on either side.  They are specially engineered to handle movements due to thermal expansion, vibrations of pumps, and misalignments due to installation tolerances, while also being resistant to the process conditions and the external influences of the application.

Types of Expansion Joints

Expansion Joint - Single ArchSingle Arch

  • Fabric and rubber construction
  • Reinforced with metal/wire rings
  • Full-face flanges integral with joint body
  • Flanges drilled to companion bolt pattern
  • Gaskets not required
  • Offset available

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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

Rubber vs. Metal Expansion Joints

An expansion joint can relieve stress in piping systems and prevent flange gaskets from being crushed.  But which expansion joint is best for your specific application?  Let us first describe the two types of expansion joints:

Rubber — a flexible connector fabricated of natural and/or synthetic elastomers and fabric and, if necessary, internal metallic reinforcements designed to provide stress relief in piping systems due to thermal movements and mechanical vibration.

Metal — a flexible element (bellows) constructed of relatively thin gauge material (generally stainless steel) designed to absorb mechanical and thermal movements expected in service.

Advantages: Metal Expansion Joints

Expansion Joints - Metal
Typical Metal Expansion Joint

Temperature
Rubber joints with standard construction and materials have an upper range to 230°F. Most manufacturers, however, can offer special constructions up to 400°F. Metal expansion joints do offer a far greater range, from -420°F to +1800°F. However, working pressures are reduced at elevated temperatures.

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