Corrugated pipe compensator also known as expansion joint and expansion joint, is mainly used to ensure pipeline operation.
Bellows compensator is a flexible, thin-walled, transversely corrugated device with expansion function, which is composed of metal bellows and components. The working principle of the bellows compensator is mainly to use its elastic expansion function to compensate the axial, angular, lateral and combined displacement of the pipeline due to thermal deformation, mechanical deformation and various mechanical vibrations. The compensation functions include pressure resistance, sealing, corrosion resistance, temperature resistance, impact resistance, shock absorption and noise reduction, which can reduce the pipeline deformation and improve the service life of the pipeline.
Working Principle
The main elastic element of the corrugated compensator is the stainless steel corrugated pipe, which is used to compensate the axial, transverse and angular direction of the pipeline depending on the expansion and bending of the corrugated pipe. Its function can be:
1. Compensate the axial, transverse and angular thermal deformation of the absorption pipe.
2. Absorb equipment vibration and reduce the impact of equipment vibration on pipeline.
3. Absorb the deformation of pipeline caused by earthquake and ground subsidence.
The compensator can be divided into unconstrained bellows compensator and constrained bellows compensator according to whether it can absorb the pressure thrust (blind plate force) generated by the medium pressure in the pipeline; According to the displacement form of bellows, it can be divided into axial type compensator, transverse type compensator, angular type compensator and pressure balance type bellows compensator.
Conditions of Use
Metal bellows compensator is composed of design, manufacturing, installation, operation management and other links. Therefore, reliability should also be considered from these aspects. In addition to its working efficiency, its medium, working temperature and external environment, as well as stress corrosion, water treatment agent, etc., should be considered when selecting materials for corrugated pipe compensator in heat supply network.
Under normal conditions, corrugated pipe materials shall meet the following conditions:
(1) High elastic limit, tensile strength and fatigue strength to ensure bellows work.
(2) Good plasticity to facilitate the forming and processing of corrugated pipes, and through the subsequent processing to obtain sufficient hardness and strength.
(3) Good corrosion resistance to meet different working environment requirements of corrugated pipes.
(4) Good welding performance to meet the requirements of the welding process to produce corrugated pipes. For the trench laid heat pipe network, when the corrugated pipe compensator is immersed in low- lying pipes, rain or accidental sewage, the materials more resistant to corrosion than iron should be considered, such as nickel alloy, high nickel alloy, etc.
Installment
1. The model, specification and pipeline configuration of the compensator shall be checked before installation, which must meet the design requirements.
2. For compensator with inner sleeve, it shall be noted that the direction of inner sleeve shall be consistent with the direction of medium flow, and the hinge rotation plane of hinge type compensator shall be consistent with the displacement rotation plane.
3. For the compensator requiring “cold tightening”, the auxiliary components used for pre deformation shall not be removed until the pipeline is installed.
4. It is forbidden to adjust the installation out of tolerance of the pipeline by means of deformation of the corrugated compensator, so as not to affect the normal function of the compensator, reduce the service life and increase the load of the pipeline system, equipment and supporting members.
5. During installation, welding slag is not allowed to splash on the surface of wave case, and wave case is not allowed to suffer from other mechanical damage.
6. After the pipe system is installed, the yellow auxiliary positioning components and fasteners used for installation and transportation on the corrugated compensator shall be removed as soon as possible, and the limiting device shall be adjusted to the specified position according to the design requirements, so that the pipe system has sufficient compensation capacity under environmental conditions.
7. All moving elements of the compensator shall not be blocked or restricted by external components, and normal operation of all moving parts shall be ensured.
8. During the hydrostatic test, the secondary fixed pipe rack at the end of the pipeline with compensator shall be reinforced to prevent the pipeline from moving or rotating. For the compensator and its connecting pipeline used for gas medium, pay attention to whether it is necessary to add temporary support when filling water. The 96 chloride ion content of the cleaning solution used for hydrostatic test shall not exceed 25PPM.
9. After the hydrostatic test, the accumulated water in the wave case shall be drained as soon as possible and the inner surface of the wave case shall be blown dry.
10. The insulation material in contact with the bellows of the compensator shall be chlorine free.
Application occasions
1. The pipeline with large deformation and limited spatial position.
2. Large diameter pipeline with large deformation and displacement and low working pressure.
3. Equipment that needs to be limited to take over loads.
4. Pipes required to absorb or isolate high-frequency mechanical vibration.
5. Pipeline required to absorb earthquake or foundation settlement.
6. The pipeline required to absorb the vibration at the outlet of the pipeline pump.
Post time: Oct-12-2022
