These expansion joints are made of one single bellows element fitted with welding ends or flanges plus a system of articulated supports which allow for angular movement in one plane only. The hinge mechanism is designed to accept full pressure thrust.
These units do not allow axial movement however, some types of hinge systems can be provided with holes for the hinge pin that are slotted to allow limited axial displacement. These “slotted hinge” types can not resist the pressure thrust forces and therefore proper anchorage must be provided.
