Expansion joints (compensators) can be classified into many types according to different classification criteria. Here are some of the main classifications:
By Material：
Metal expansion joint: Usually used in high temperature and high pressure working conditions, materials include stainless steel, carbon steel, alloy steel, etc.
Non-metallic expansion joint: Suitable for low temperature and low pressure environment, materials include fluororubber, silicone, fiber fabric, etc.
Classification by structure：
Bellows expansion joint: The most common type, utilizes the elasticity of the bellows to absorb the displacement of the pipe.
Sleeve expansion joint: Absorption of axial displacement by relative sliding of the inner and outer sleeves.
Spherical expansion joint: The angular displacement is absorbed by the rotation of the ball joint.
hinged expansion joint: The hinge structure is used to absorb angular displacement.
universal expansion joint: In combination with multiple expansion joint units, displacement can be absorbed in multiple directions.
Classified by displacement compensation method：
Axial expansion joint: Only axial displacement can be absorbed.
transverse expansion joint: Absorbing lateral displacement.
Angular Expansion Joint: Absorbing angular displacement.
Pressure balanced expansion joint: Balance the thrust generated by internal pressure while absorbing displacement.
Classification by ability to compensate：
Single wave expansion joint: There is only one corrugated expansion joint.
Multi-wave expansion joint: With multiple corrugations, it can provide greater compensation capacity.
By application environment：
High temperature expansion joint: Used in high temperature environments, such as boilers, petrochemical units.
Low temperature expansion joint: For low temperature environments, such as liquefied natural gas (LNG) facilities.
Corrosive media expansion joint: Pipeline for transporting corrosive media such as acid, alkali, salt solution, etc.
Classified by Connection：
Flanged connection expansion joint: Connected to pipe by flange.
Welding expansion joint: Welded directly to the pipe.
Classification according to the waveform structural parameters of bellows：
U-shaped expansion joint: Most common corrugated shape.
ω-shaped expansion joint: Provides greater compensation capacity.
S-shaped expansion joint: Suitable for certain special working conditions.
V shaped expansion joint: Less common, but has its specific application.
Each type of expansion joint has its specific application scope and design characteristics. Selecting the appropriate expansion joint type needs comprehensive consideration according to the working conditions of pipeline system, media properties, displacement types and other factors. In practical applications, the selection and design of expansion joints usually require professional engineers to carry out according to specific project requirements.