Corrugated compensator, also called expansion joint, or expansion joint. It is composed of bellows and end pipes, brackets, flanges, conduits and other accessories that constitute the main body of its work. Mainly used in various pipelines, it can compensate the thermal displacement of the pipeline, mechanical deformation and absorb various mechanical vibrations, play the role of reducing the deformation stress of the pipeline and improving the service life of the pipeline.
The connection method of the corrugated compensator is divided into flange connection and welding. The directly buried pipeline compensator is generally welded, except for trench installation. The nominal displacement of the general-purpose bellows is actually the capacity of the bellows to be deformed by the given nominal displacement. For expansion joints and compensators made of bellows, it is usually called the compensation amount, which reflects the ability of the bellows to absorb the displacement of the system, and represents the maximum compensation ability of the product under certain conditions. When the bellows is working normally, it must absorb the displacement of the system and generate displacement deformation, and at the same time, it must ensure a certain number of normal safe working displacement cycles.
Therefore, when the bellows is designed, according to the displacement that each wave can withstand, a certain number of corrugations is designed. When each wave is evenly subjected to the displacement load and there is no local overload, the bellows can work normally. When the design is reasonable, a certain number of design working displacement cycles can be guaranteed.
Classification of ripple compensators:
Disposable Bellows Compensator
U-shaped metal expansion joint bellows compensator
Three-dimensional pulverized coal special corrugated compensator
Hinge ripple compensator (JJL type)
Balanced curved pressure bellows compensator
Spherical QB stainless steel corrugated compensator, etc.
Non-metal
Non-metallic flexible compensator: also known as non-metallic expansion joint, non-metallic fabric compensator, can compensate axial, lateral, angular, with no thrust, simplified bearing design, corrosion resistance, high temperature resistance, noise reduction and vibration reduction, etc. , especially suitable for hot air ducts and smoke ducts.
Features:
1. Compensation for thermal expansion: It can compensate for multiple directions, which is much better than the metal compensator that can only compensate in one way.
2. Compensation for installation error: Since the system error is unavoidable in the process of pipeline connection, the fiber compensator can better compensate the installation error.
3. Noise reduction and vibration reduction: The fiber fabric and thermal insulation cotton body have the functions of sound absorption and vibration isolation transmission, which can effectively reduce the noise and vibration of boilers, fans and other systems.
4. No reverse thrust: Because the main material is fiber fabric, it can be transmitted weakly. Using fiber compensators simplifies the design, avoids the use of large supports, and saves a lot of material and labor.
5. Good high temperature resistance and corrosion resistance: The selected fluoroplastics and silicone materials have good high temperature resistance and corrosion resistance.
6. Good sealing performance: There is a relatively complete production and assembly system, and the fiber compensator can ensure no leakage.
7. Light weight, simple structure, convenient installation and maintenance.
8. The price is lower than the metal compensator, and the quality is better than imported products.
Stainless steel
There are four types: straight, double, angular and square.
The stainless steel compensator can compensate axial, lateral and angular directions, and has the characteristics of no thrust, simplified bearing design, corrosion resistance, high temperature resistance, noise reduction and vibration reduction, etc. It is especially suitable for hot air ducts and smoke and dust ducts.
Metal
The reliability of the metal corrugated compensator is composed of multiple links such as design, manufacture, installation and operation management. Reliability should also be considered from these aspects. Material selection For the selection of corrugated pipes used in the heating pipe network, in addition to the working medium, working temperature and external environment, the possibility of stress corrosion, the influence of water treatment agents and pipe cleaning agents on materials, etc. should also be considered. On this basis, combined with the welding and forming of the bellows material and the performance-price ratio of the material, an economical and practical material for making the bellows is selected.
In general, the material used for bellows should meet the following conditions:
(1) High elastic limit, tensile strength and fatigue strength to ensure the normal operation of the bellows.
(2) Good plasticity is convenient for the processing and forming of bellows, and sufficient hardness and strength can be obtained through subsequent processing processes (cold work hardening, heat treatment, etc.).
(3) Good corrosion resistance to meet the working requirements of bellows in different environments.
(4) Good welding performance, meeting the welding process requirements of bellows in the production process.
For the thermal pipe network laid in the trench, when the compensator is located in a low terrain, the bellows will be soaked by rainwater or accidental sewage, and materials with stronger corrosion resistance should be considered, such as iron-nickel alloys, high-nickel alloys, etc. Due to the high price of such materials, when manufacturing bellows, it can be considered to only add a layer of corrosion-resistant alloy to the surface in contact with the corrosive medium. Fatigue life design From the failure type and cause analysis of the bellows compensator, it can be seen that the plane stability, circumferential stability and corrosion resistance of the bellows are all related to its displacement, that is, the fatigue life. Too low fatigue life will lead to a decrease in the stability and corrosion resistance of metal bellows.
