Most rubber expansion joint failures are the result of not using control units when required.
Unrestrained, most rubber expansion joints will extend when pressurized. It is preferable to anchor the piping system to prevent this, but when proper anchoring is not practical, control units must be used. (See the installation instructions for more details.)
A minimum of two control rods are required, however the number of rods required depends on the joint size and the operating pressure of the system (click the submittal sheet button below for details). Standard control units are not required for the Ultraspheres with Cables, as the cabling acts as the control unit.
Gusset plates are bolted behind the mating flanges and control rods are used between them to limit the extension of the expansion joint.