The compensator is also called the extender or expansion joint and expansion joint, which is mainly used to compensate the heat expansion and cold contraction produced by the temperature change of the pipe. If the pipe is not completely free to expand or shrink when the temperature changes, the thermal stress will be produced in the pipe. This stress must be considered in the design of the pipeline, otherwise it may cause the rupture of the pipe and affect the normal production. As an important part of the pipeline engineering, the compensator plays an important role in ensuring the long term normal operation of the pipeline.
One. Classification of compensators
The compensator is divided into metal ripple compensator, non-metallic Compensator, sleeve compensator, square compensator and so on. Metal ripple compensator and non-metallic Compensator are common in use.
1. The metal ripple compensator is composed of the bellows (an elastic element) and the accessories of the end pipe, the bracket, the flange and the catheter. It belongs to a compensation element. The effective expansion and deformation of bellows should be utilized to absorb the size changes caused by thermal expansion, shrinkage and other reasons, or to compensate for axial, lateral and angular displacement of pipelines, pipes and containers. It can also be used for noise reduction and vibration reduction. It is widely used in modern industry.
2, the non-metallic Compensator can compensate for the axial, lateral and angular displacement of pipelines. It has the characteristics of no thrust, simplified bearing design, corrosion resistance, high temperature resistance, noise reduction and vibration absorption, and is especially suitable for hot air pipes and dust pipes.
Two. The function of the compensator:
1, to compensate for the axial, transverse and angular thermal deformation of the absorption pipe.
2.. The expansion of the ripple compensator is convenient for the installation and disassembly of the valve pipe.
3, absorbs the vibration of the equipment, reduces the influence of the equipment vibration to the pipe.
The deformation of the pipeline, 4, absorption of seismic subsidence.
Three, compensator standard
Standard number: GB/T12777-1999 (new standard GB/T12777-2008)
Standard name of compensator: General technical conditions for metal bellows expansion joint
Standard implementation date: 2000-3-1 (new standard implementation date 2009-02-01)
Promulgation Department: State Bureau of quality and technology supervision
Introduction: this standard specifies the definition, classification, requirements, test methods, inspection rules, marking and packaging, transportation and storage of metal bellows compensator. This standard is applicable to the flexible parts installed in the pipeline for the overall shape without strengthening U shape, strengthen the design, manufacturing and inspection of circular compensator U shaped and inverted U-shaped bellows. The design, manufacture and inspection of the compensator for pressure vessels can also be used as reference.
Four, the principle of type selection of compensator
Due to various constraints is quite complex, but any complex pipe system can use a plurality of fixed bracket to select different settings in different parts, divided into several separate pipe shape is relatively simple, "Z" type pipe and an n-shaped pipe section, and determined the deformation and the amount of compensation for each pipe segment, because a lot of compensator types, correct selection is very important, so in the design of piping system, should fully consider the direction of the pipeline and support system (including fixed tube frame, sliding tube frame) design and considering the shape and configuration of the compensator to achieve the best combination, safe, reasonable, applicable and economical.
Five. The picture display of the compensator product
Six. The installation requirements of compensator
1. When the insulation pipe is buried in the ground, the sand is filled with grain of less than 20 millimeters, and then the original soil is covered. The thickness of the filled sand is not less than 200 millimeters.
2, the installation of the direct burial compensator does not need to be cold and tight, and it does not need to be reproduced and rewelded after the pipe is reconnected and expanded. There is no need for a guide bracket to use a directly buried expansion joint.
3, the buried depth of the top of the insulation pipe is generally not more than 1.2 meters, but also not less than 0.7 meters, the insulation pipe can be buried directly under the various pipes.
4, when installing, we should ensure that the direction of the guide sleeve is consistent with the flow direction.
5, the medium in the expansion joint should be treated with the removal of free oxygen and chloride ion, and the content of chlorine ion should not exceed 25PPm. 6, before the compensator is installed to carry out the hydraulic test of the system, the two ends of the pipe should be fixed to prevent the internal pressure thrust tension compensator.
7, the expansion joint allows a system water pressure test that does not exceed 1.5 times the nominal pressure.
Seven, the application field of compensato
The compensator is usually installed in hot water, steam, smoke, gas and other thermal pipes, and the amount of deformation caused by the heat absorption of the absorption pipe. It is mainly used in the following areas
1, thermal power plant: boiler, gas turbine exhaust system, dust removal system.
2. Petrochemical Enterprises: flue gas desulfurization and desulphurization devices for boiler and industrial furnace, and wet and dry ventilation ducts.
3, iron and steel works: blast furnace, converter, exhaust and other dust removal system.
4. Thermal power plant: exhaust and hot water circulation and various heating units
5, smelting plant: combustion furnace and other supply and exhaust systems.
6, cement plant: kiln, dust collection, smoke and dust treatment system.
7, device category: dust collector, absorption tower, air heater, air blower equipment import and export.
8, civil: the compensator for pipeline, gas pipeline, heating and heating pipeline, etc.
9. The exhaust system of marine diesel engine: gas turbine exhaust system
Eight, the application case of compensator
As a flexible compensator with free expansion, the compensator has the advantages of reliable operation, good performance and compact structure. It relies on bellows expansion and bending to make axial, lateral and angular compensation for pipelines.