A single hinged expansion joint is designed to permit angular rotation in one plane, by the use of a pair of pins through hinge plates attached to the expansion joint ends.
Hinged joints are used in sets of two or three, to absorb pipe movement in one or more directions in a single plane piping system.
Expansion joint hinges are designed to transmit the full pressure thrust of the expansion joint. A hinged system permits large movements to be absorbed with minimal anchor forces.
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 cannot resist the pressure thrust forces and therefore proper anchorage must be provided.