JS Graphics – EbbaIron FlexTend®: Protecting Pipelines with Force Balanced Flexibility

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In 1989, Ebba Iron Incorporated introduced the FlexTend flexible expansion joint, revolutionizing pipeline protection. This innovative product was designed to safeguard pipelines and their connections from differential movement caused by seismic activity, soil subsidence, and thermal expansion and contraction forces. Unlike previous options, the FlexTend combined two ball joints separated by an expansion joint into a single, comprehensive solution. Over the years, it has proven to be highly effective, particularly in earthquake-prone areas.

The Problem of Thrust Forces

While the FlexTend provides excellent protection against movement, it also introduced a new challenge: the issue of thrust forces. Thrust forces are generated due to hydrostatic pressure inside pipelines. Calculating the maximum thrust force is straightforward – it is the product of the highest pressure (in psi) the pipeline will experience and the cross-sectional area (in square inches) of the pipeline.

Typically, the use of restrained joints is sufficient to counteract these thrust forces. However, in areas where expansion and contraction are required, the traditional expansion joint becomes necessary. Unfortunately, if left unaccommodated, the thrust force and resulting joint expansion can cause damage to the pipeline and surrounding structures.

Introducing the Force Balanced FlexTend

Recognizing this challenge, Ebba Iron developed the Force Balanced FlexTend. This enhanced version of the FlexTend incorporates a second cylinder that generates an equal but opposite thrust force. When two forces of equal strength push against each other in opposite directions, they effectively nullify each other, resulting in a balanced system. This ingenious design eliminates the concerns associated with thrust forces while providing the same level of pipeline protection against movement and stress.

Benefits of the Force Balanced FlexTend

  1. Protection from Movement: Just like the standard FlexTend, the Force Balanced FlexTend offers exceptional protection against the stress of pipeline movement caused by various external factors.

  2. Elimination of Water Volume Changes: Unlike traditional expansion joints, the Force Balanced FlexTend avoids volume changes that can lead to spikes in water pressure during seismic events or rapid actuation. This eliminates potential damage to the pipeline and ensures consistent water pressure.

  3. Streamlined Pipeline Design: With the Force Balanced FlexTend, engineers can simplify pipeline design by removing the need for additional restraint mechanisms, such as thrust blocks or force-restricting devices. This leads to cost savings and a smaller required footprint.

  4. Cost-Effective Solution: The Force Balanced FlexTend offers all the benefits of traditional expansion joints but at a lower cost. By eliminating the need for expensive restraint mechanisms, it allows for more economical pipeline projects.

Step-by-Step Process for Implementing the Force Balanced FlexTend

  1. Assess Pipeline Requirements: Determine if your pipeline project requires protection against differential movement caused by seismic activity, soil subsidence, or thermal expansion and contraction forces.

  2. Calculate Thrust Forces: Using the highest pressure the pipeline will experience and the cross-sectional area, calculate the maximum thrust force. This will help determine if a traditional expansion joint is needed or if the Force Balanced FlexTend is a suitable alternative.

  3. Specify the Force Balanced FlexTend: If the project requires protection against movement and thrust forces, specify the Force Balanced FlexTend in the pipeline design. Consider the advantages of its streamlined design, elimination of water volume changes, and cost-effectiveness.

  4. Installation: Follow the manufacturer’s instructions for the correct installation of the Force Balanced FlexTend. Ensure proper alignment and connection to the pipeline to guarantee optimal performance and longevity.


When it comes to protecting pipelines from movement and stress, the Force Balanced FlexTend from Ebba Iron is an ideal solution. Its innovative design, incorporating a second cylinder to counter thrust forces, ensures pipeline safety without compromising on cost or effectiveness. By choosing the Force Balanced FlexTend, engineers can streamline pipeline design, eliminate the need for additional restraint mechanisms, and ultimately save on project costs. With its unparalleled flexibility and reliability, the Force Balanced FlexTend is the go-to choice for pipeline protection.

For more information or to purchase the Force Balanced FlexTend, visit the official Ebba Iron website. Safeguard your pipelines with this advanced solution and ensure a secure and efficient pipeline system.

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