The metal expansion joint has excellent flexibility and excellent performance when it is used to absorb the displacement caused by the thermal expansion of the pipeline and the vibration generated by the machine. However, because of its excellent flexibility, if it is not installed properly, it will not only not give full play to its excellent performance, but also be prone to damage. Therefore, it is very important to correctly carry out the support design and stress calculation for the pipeline with compensator, calculate the transverse and longitudinal displacement and its stress state, and accurately select the distance between various supports and supports.
Expansion joints are also called expansion joints or expansion joints. It consists of bellows and accessories. It belongs to the compensation component. The expansion and contraction of the bellows of the working body can absorb the dimensional changes caused by the thermal expansion and contraction of the pipeline, conduit and container, or compensate the axial, transverse and angular displacement of the pipeline, conduit and pipeline. Container. It can also be used to reduce noise and vibration. It is widely used in modern industry. In terms of heating, in order to prevent the deformation or damage of the heating pipe due to thermal elongation or temperature stress during heating, a compensator needs to be installed on the pipe to compensate for the thermal elongation of the pipe., So as to reduce the stress and stress on the pipe wall. The force acting on the valve or supporting structure.
The metal expansion joint adopts rectangular section and fillet waveform. A single compensator in the pipeline bears two-dimensional displacement. The elbow pipe composed of two compensators can withstand three-dimensional displacement. The rectangular fillet metal expansion joint has full height and half height types. According to the flue size and stress-strain requirements, users can choose multiple wave joints.
1. After selecting an appropriate compensator according to the thermal displacement of the pipe system, the user must at least provide the circulating medium in the pipe, the design pressure of the smoke and air duct, the higher temperature during operation, the overall dimension (length and width) of the cross section of the smoke and air duct, the selected waveform (full height 216mm, half height 108mm) and wave number (the number of single wave of a single wave does not exceed 6 waves) for the structural design and manufacture of the compensator.
2. Allowable expansion per wave: full height type △ α= ± 24mm half height type △ α= ±12mm。
3. Ash baffle: it can not be used for air duct or less dusty pipeline, and ash baffle shall be used for dusty flue.
4. In order to reduce the number of wave nodes of bellows, 50% cold drawing shall be considered.
5. The compensator is applicable to the occasions where the cross-sectional area is less than 4.6 square meters and one side of the overall dimension of smoke and air duct is less than 1.5m but greater than 0.6mm. The standard full height corrugated compensator is applicable to all smoke and air ducts.
The elbow force balanced metal compensator is used for the connection between machine equipment and machine equipment. Its effect is to compensate the thermal deformation of the intermediate pipeline between the two equipment, reduce the force caused by installation deviation on machine equipment and facilitate installation. The selection of elbow force balanced corrugated compensator can prevent the machine and equipment from the blind valve force caused by gas pressure. The rotary compensator can improve the bearing capacity of the machine and equipment, and the machine and equipment can be fixed at will.
Requirements for normal use and installation of metal expansion joints:
1. The metal expansion joint shall be selected according to the needs of the pipe system and the rated compensation. The metal expansion joint shall be subject to pre tension and compression test before leaving the factory. The pre tension and compression test shall meet the design requirements.
2. The selection of metal expansion joint shall meet the use requirements, and its specification and model shall meet the design requirements and be consistent with the pipe system design. Compensators that do not meet the design requirements shall not be used.
3. The metal expansion joint with guide pipe shall be consistent with the flow direction of medium, so as to avoid the accumulation of sundries and affect the use of metal expansion joint.
4. When installing the metal expansion joint, it is strictly forbidden to forcibly adjust the installation error between the metal expansion joint and the pipeline with the deformation of the metal expansion joint, so as not to affect the normal use function of the metal expansion joint. The rotary compensator will reduce the service life of the metal expansion joint.
5. The metal expansion joint shall be installed in the cold state, and its installation error shall be controlled within: the center line of the interface between the two ends of the pipe and the metal expansion joint shall be kept on the same center line, the coaxiality error shall be ± 5mm, and shall not exceed ± 15mm under the working state; The deviation displacement angle of up, down or left and right is ± 0.1 °; The reasonable installation length of compensator is l ± 5mm.
6. After the metal expansion joint is installed, the auxiliary positioning components and fasteners used for installation and transportation on the metal expansion joint shall be removed as soon as possible, and the limit device shall be adjusted to the specified position according to the design requirements, so that the pipeline has sufficient compensation capacity under environmental conditions.