Classification by structure.
1. Single type ordinary expansion joint
(1) Single type ordinary expansion joint with tie rod: used to absorb lateral displacement and axial displacement in the tie rod. The feature is that the pull rod can absorb the thrust generated by pressure, but the effective length of the bellows is small, which can only absorb small lateral displacement.
(2) Single type ordinary expansion joint without tie rod: used to absorb axial displacement. The thrust generated by pressure cannot be absorbed.
2. Double universal expansion joint
(1) Double universal expansion joint with tie rod: used to absorb lateral displacement and axial displacement in the tie rod. The longer the length between the two groups of ripples is, the more lateral displacement will be absorbed, but the tension will also increase accordingly. Due to the limitation of stiffness, the pull rod cannot be too long.
(2) Compound square expansion joint with short tension: used to absorb lateral displacement and axial displacement. Since there is no limit of pull rod, the length between two groups of bellows can be very long, so it can absorb large lateral displacement and axial displacement. However, the thrust generated by the pressure shall be borne by the main fixed support.
3. Single type chain expansion joint
(1) Planar single chain expansion joints: commonly used in L-shaped, n-shaped and planar 2-shaped pipes, more than two single chain expansion joints are set to absorb the lateral displacement and axial displacement, and the thrust generated by pressure is absorbed by the chain.
(2) Universal single chain type expansion joint can absorb angular displacement in any direction. It is usually combined with single chain type expansion joint for solid z-shaped pipe, which is thick and bulky.
4. Retest the chain expansion joint
(1) Plane compound chain expansion joint is used for L-shaped and plane 2-shaped pipes to absorb lateral displacement. The pull plate is more rigid than the long pull rod of the compound universal type. A longer pull plate can be used to absorb more lateral displacement and axial displacement. Its disadvantage is that it can only absorb the displacement of the plane.
(2) Universal compound chain type expansion joint can absorb displacement in any direction due to the application of pin blocks in the chain. It is commonly used for elevation z-shaped pipes.
Classification by use.
1. Axial expansion joint
An expansion joint used to absorb axial displacement. There are mainly two types of single ordinary expansion joints without tie rods and axial expansion joints. Under the action of external hand pressure, the column stability of the expansion joint is better than that under internal pressure. However, the structure of the axial expansion joint under external pressure is more complex. Once, the axial expansion joint under external pressure is used only when there are many wave numbers required and column instability will occur under internal pressure.
2. Transverse displacement expansion joint
An expansion joint used to absorb transverse displacement. There are mainly multiple universal expansion joints, ordinary expansion joints with tie rods, and multiple chain expansion joints.
3. Angular displacement expansion joint
An expansion joint used to absorb angular displacement. It is mainly chain expansion joint. Two or more are often used together to absorb lateral displacement.
4. Pressure balanced expansion joint
It can balance the thrust generated by pressure, and is used in situations where large thrust is not allowed. The main types are elbow pressure balanced expansion joint, straight pipe pressure expansion joint and bypass pressure balanced expansion joint.
5. High temperature expansion joint
In general, the bellows, the main component of the expansion joint, operates under high stress, and the bellows material is prone to creep at high temperature, which greatly reduces the fatigue life. Therefore, when the medium temperature is higher than the creep temperature of the corrugated pipe material, the heat insulation method should be used, such as the expansion joint of the blast furnace or the method of steam cooling, such as the expansion joint, to reduce the wall temperature of the corrugated pipe material and make the corrugated pipe work at a safe temperature.
Post time: Dec-22-2022
