There is a strong demand for stainless expansion joints in 2” thru 16” diameter with 2” axial and 1/4” transverse capability. Weld ends are most common, but there are also flanged requirements. All our flanged joints have one floating flange to facilitate installation and eliminate torsional stress. The other is raised face.
Like many companies, not only were our deliveries extended, but whenever an inquiry came in, we would redesign and re-cost needlessly. We decided the thing to do was stock all sizes 2” through 16”, as shown in our dimension tables.
There seems to be some confusion as to what 2” travel means, so let’s go over it. Every expansion joint has its neutral length. From this neutral position, the joint can be used for a full 2” compression or 2” expansion, but never a combination of the two. They are perfectly suitable for 1” compression and 1” extension or as a further example, 1 1/2” compression and 1/2” extension. In other words, in its working life, total movement should never exceed combined 2”.
There is a common misconception that you can take a 2” movement expansion joint, extend it 1”, and then use it for a compression of 3”. No matter where this information came from, it is wrong.
What determines the life of an expansion joint is the stress cycle, the total bending from one extreme to the other over its life time. Let’s think of a flat strip of sheet metal. Place it in a vise and bend it to one side 2” and then bring it back to the vertical. After a given number of cycles, this strip will crack at the bending point, based on the bending stress cycle for having moved the 2” and back to neutral.