An expansion joint, also known as a compensator, is a device used to absorb displacement in a piping system due to thermal expansion and contraction, vibration, installation errors, and more. Its composition varies depending on the type, but the basic components are similar. Here are several common types of expansion joints and their main components:
Metal corrugated expansion joint
Bellows(Bellows): Core assembly composed of multi-layer metal sheet corrugations for absorbing displacement.
Take over(End Fittings): The sections that connect bellows to pipes, usually flanges or welded ports.
limiting device(Limiting Devices): such as tie rods or guide brackets, used to limit the amount of displacement of the bellows and prevent over-extension or compression.
Liner tube(Inner Liner): Sometimes inside the bellows, used to prevent direct contact of the media with the bellows, especially in corrosive media.
Reinforcement ring(Reinforcing Rings): Used to increase the stiffness and stability of the bellows.
Non-metallic expansion joint
skin(Skin): Made of rubber, fluororubber, silicone or other non-metallic materials, forming the main flexible part of the expansion joint.
frame(Frame): Supports the skin and maintains the shape and structural integrity of the expansion joint.
stiffener(Stiffeners): Used to increase the stiffness and stability of non-metallic skin.
Thermal insulation(Insulation): Used to reduce heat transfer in high temperature applications.
inner liner(Liner): Wear-resistant layer that directly contacts the medium to protect non-metallic materials.
Sleeve expansion joint
Outer sleeve(Outer Sleeve): It is fixed and serves as the external structure of the whole expansion joint.
inner sleeve(Inner Sleeve): can be moved in the axial direction for absorbing displacement.
Sealing material(Sealing Material): Prevent media leakage, located at the contact surface between the inner and outer sleeves.
Guide(Guiding Mechanism): Ensure that the inner sleeve moves smoothly in the axial direction.
spherical expansion joint
sphere(Sphere): The core of the expansion joint, allowing angular displacement in multiple directions.
Tee(Socket): Matches the sphere and is used to fix the sphere and transfer the load.
sealing ring(Seal): Prevent media leakage, located between the ball and the ball seat.
The details and design of these components will vary depending on the specific application environment and the manufacturer's design. Factors such as displacement type (axial, transverse, angular), operating temperature, medium type, pressure, and pipe size need to be considered when choosing and designing expansion joints.