Lateral refers to the direction perpendicular to the centerline of the pipe expansion joint (in any plane). Other terms for this deflection are PARALLEL OFFSET and TRANSVERSE. This movement occurs with both of the ends of the pipe expansion joint remaining parallel to each other, with their centerlines being displaced, or no longer coincident.
When analyzing the deflections in a piping system, it is not uncommon to find that different lateral deflections can occur in more than one plane. Since a pipe expansion joint is round, these various deflections must be resolved into a single resultant lateral deflection, in order for the bellows to be properly selected in terms of the rated LATERAL DEFLECTION shown in this catalog.
The magnitude of the resultant LATERAL DEFLECTION is the square root of the sum of the squares of the individual deflections. The planes of the various deflections must also be clearly understood if the pipe expansion joint is to contain structural components such as hinges, which may inhibit movements in certain directions, and if the individual deflections can occur separately during the life of the pipe expansion joint.
6″ dia. Universal Expansion Joints for a Power Generation Plant