Hinged Expansion Joints have a single bellows and have their length restrained by the addition of hinge mechanism which is strong enough to accept the pressure generated thrust but will allow angular movement in a single plane.
Slotted Hinge Expansion Joints are a variant of the above "Hinged" type, in that while providing for angular movements, some axial movement can be accepted because the hinge pin passes through slots in the hinge plates. When the axial movements is occurring the expansion joint is incapable of accepting the pressure thrust. The hinge structure can be designed to accept the full pressure thrust when the pin is at the limit of its travel within the slot

Hinged Expansion Joints have a single bellows and have their length restrained by the addition of hinge mechanism which is strong enough to accept the pressure generated thrust but will allow angular movement in a single plane.
Slotted Hinge Expansion Joints are a variant of the above "Hinged" type, in that while providing for angular movements, some axial movement can be accepted because the hinge pin passes through slots in the hinge plates. When the axial movements is occurring the expansion joint is incapable of accepting the pressure thrust. The hinge structure can be designed to accept the full pressure thrust when the pin is at the limit of its travel within the slot