CYCLE LIFE AND RATED MOVEMENT

U-FLEX UNIVERSAL EXPANSION JOINTS

PT&P's U-Flex universal expansion joints are designed for 3000 cycles for any one tabulated movement shown. Cycle life may be increased, or movement may be increased (decreasing the cycle life) by utilizing the graph shown on this page. The graph may also be used for superimposing more than one movement condition on the bellows at one time. It is important to remember that the movements shown in the bellows data pages do not allow for any installation misalignment. A proper specification for a bellows expansion joint should reflect what the actual system movements will be. To insure the highest quality bellows for the least cost, all movement conditions must be taken into account. Refer to the HOW TO ORDER section on page 77 for an example on the proper analysis and selection of a U-Flex expansion joint.

Examples of movement conditions that typically occur in a piping system are:

• INSTALLATION Allow one cycle installation misalignment.

• START-UP/SHUT DOWN Movements produced between the minimum ambient temperature and the maximum start-up temperature. This is normally a very low number of cycles.

• OPERATING Movements produced due to temperature fluctuations during system operation. This is typically a very small movement for a very large number of cycles.


• EXCURSION Movement resulting from a worst case/ upset scenario, occurring during system operation. This is normally a very low number of cycles.

How to Use Graph

• Enter the graph horizontally at the number of anticipated cycles or the movement condition being considered.
• Move vertically until the graph is intercepted.
• Move horizontally and read conversion factor.

Example: Enter graph at 1,000 cycles; read C. F. of 0.80

Note: Maximum increase in movements for combined movement conditions shall not exceed 110% of catalog rated movement

Note: Please reference the print version of Piping Technology & Products' Expansion Joint Catalog for reference tables containing technical data on U-Flex Expansion Joints.

How to Select and Order U-Flex Joints