The Kadant Blog

Proper Fit and Alignment of Expansion Joints Crucial to Overall Performance

Secureflex install01 SMA defining strength of Kadant Unaflex is the ability to respond to a customer’s needs in an urgent manner. Often in the expansion joint industry, there is a sense of urgency. When a primary power plant is offline due to a failure of an expansion joint, they need a replacement very quickly. Sometimes these scenarios are easily resolved with stock sizes and configurations. More often than one may think, that urgent need requires a special build and that is where Kadant Unaflex excels.

One example of this situation involved a power plant in the northeast. The customer was using standard expansion joint sizes and were continually replacing them. One such failure led to a shutdown in a peak power season. Kadant Unaflex was contacted regarding this situation. Our experts realized much of the failure was due to mismatch of the butterfly valve connection and raised face flange on the straight expansion joint. The mismatch of connection along with offsetting of the pipe ends needed a better solution.

Secureflex install02 SMMisalignment of pipe ends are a common cause of misfitting expansion joints. The misalignment creates unneeded stress on the body of the joint by perpetuating a flex and handicapping the movement capabilities of the expansion joint. Offsetting will often accentuate this stress on the face of the expansion joint creating pockets where leaks and pressure loss will occur. In this case, this was amplified by the flange of the butterfly valve coupled with raised face flanges on the straight expansion joints being used.

Secureflex install03 SNKadant Unaflex’s resolution to this problem was the SecureFlex 7000 expansion joint with a built-in offset. Our production team built the body of the expansion joint to allow for proper seating of the faces on the misaligned pipes. The SecureFlex style expansion joint comes standard with rotating coated steel flanges allowing for a more secure fit when properly tightened. The Van Stone or floating flange design of the SecureFlex expansion joint allows for drilling misalignment to be handled in an easy manner. The rush capabilities of our manufacturing allowed us to get the equipment out quickly. Once the SecureFlex expansion joint was installed, the failure issues the customer had been continually facing were no longer an issue.



  • Written by:

    Jason Pruitt

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