1. Expansion joints(compensators)
Expansion joints, also known as compensators, are vital components
comprising one or more bellows as the primary elastic element,
along with connectors, supports, flanges, conduits, and other
accessories. These flexible structures are installed on vessel
shells or pipelines to counteract additional stresses resulting
from temperature fluctuations and mechanical vibrations. By
harnessing the expansion and contraction of the bellows, they
accommodate dimensional changes in pipelines, conduits, and vessels
caused by thermal expansion, contraction, axial, lateral, and
angular displacements.
Apart from compensating for dimensional changes, expansion joints
also serve purposes such as noise and vibration reduction and
supporting heating supply systems. To prevent damage to heating
pipelines due to thermal expansion, compensators are installed to
mitigate the stress on the pipeline walls and the forces exerted on
valves or support structures.
Due to their ability to freely expand and contract, expansion
joints offer advantages like reliable operation, high performance,
and compact structure. As a result, they find widespread use in
chemical engineering, metallurgy, nuclear energy, and other
industries. Expansion joints come in various forms, with U-shaped
expansion joints being the most common, followed by Ω-shaped and
C-shaped joints for vessel applications. For pipeline use, they are
categorized based on structural compensation into universal,
pressure balanced, hinged, and gimbal expansion joints.
| Main Item | Classification | Description |
| Metal Expansion Joint | Elbow Expansion Joint | Bend the pipe into a U-shaped or other shape, also known as tension
bends,are a type of expansion joint that utilizes the elastic
deformation ability of the form to compensate. Its advantages are
good strength, long service life, and on-site production.The
disadvantages are space-consuming, high steel consumption, and high
friction resistance. This type of expansion joint is widely used in
various steam piping and long pipes. |
Bellows Expansion Joint
| A bellows expansion joint is an expansion joint made of metal
bellows. It can expand and contract along the axial direction of
the pipeline, and also allows a small amount of bending. In order
to prevent exceeding the allowable compensation amount, protective
rods or rings are installed at both ends of the bellows, and guide
supports are installed on both ends of the connected pipelines.
There are also angular and lateral expansion joints, which can be
used to compensate for rotational deformations and lateral
deformations of pipelines. The advantages of these expansion joints
are space-saving, material-saving, easy standardization, and mass
production, but the disadvantage is the relatively short lifespan.
Bellows expansion joints are generally used in short pipelines with
low temperature and pressure. With the improvement of bellows
production technology, the application scope of this type of
expansion joint is expanding. Currently, bellows expansion joints
can be used in pipe systems with a maximum pressure of 6.0 MPa. |
| Slip-Type Expansion Joint | The slip-type expansion joint has inner and outer sleeves for axial
movement, sealed with stuffing box. It compensates for pipeline's
axial expansion and rotation, suitable for hot water, steam, and
grease. The inner sleeve slides against the outer one to adjust for
thermal expansion. Connected to the pipeline, it uses a
high-performance self-sealing seal. A new synthetic seal material
between the sleeves resists heat, corrosion, and aging (-40°C to
150°C, up to 350°C under special conditions), ensuring sliding and
preventing leakage. |
| Non-metallic Expansion Joint | Rubber Expansion Joint | Composed of rubber and rubber-fiber composite materials, steel
flanges, sleeves, and insulation materials, it is mainly used for
flexible connections between various fans and ducts. Its functions
include shock absorption, noise reduction, sealing, medium
resistance, easy displacement and installation. It is an ideal
accessory for shock absorption, noise reduction, smoke and dust
removal in the field of environmental protection. |
| Fabric Expansion Joint | The fabric expansion joint is mainly made of fiber fabric, rubber,
and other high temperature resistant materials. It can compensate
for the vibration and deformation of fans and ducts.Fabric
expansion joints can compensate for axial, lateral, and angular
products, with features such as no thrust, simplified support
design, corrosion resistance, high temperature resistance, noise
reduction, vibration reduction,and others.It is particularly
suitable for hot blast pipes and smoke and dust pipeline of power
plant.The non-metallic compensator's fiber fabric and insulation
cotton itself have the functions of sound absorption and vibration
isolation, therefore they can effectively reducing the noise and
vibration of boiler, fan, and other systems. Simple structure,
light weight, and easy maintenance. |
Super Austenitic Stainless Steel:254SMO,904L,AL6XN
Duplex Stainless Steel :2205
Dual phase steel (S31803)
Nickel Based Alloy
Steel:INCOLOY800/800H/800HT/840/825,INCONEL600/601/690/625/X-750
Hastelloy Alloy C-276/C-22/X,MONEL400/K500
Pure Nickel:N4,N6(Ni200,Ni201)
Titanium Plate For Stamping:GR1,GR2,TA1,TA2
Austenitic Stainless
Steel:SUS304,SUS304L,SUS316,SUS316L,SUS310S,SUS321,SUS316Ti
2. Non-metallic Expansion joints
- Non-metallic compensators/expansion joint types
Non-metallic compensators encompass various types, including
straight cylindrical, compound, angular, and square expansion
joints.
Rectangular non-metallic compensators, primarily employed in power
plant flue ducts, serve to absorb thermal displacement and shock.
These compensators can be connected via flanges or nozzles.
- Common structural types of non-metallic compensators (non-metallic
expansion joints) include the following six:
- Technical parameters of non-metallic compensators (non-metallic
expansion joints):
Compensating segment length(h/m)
| 100 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 550 | 600 | 650 | 700 | 800 | 900 |
Compensation volume(nm)
| Axial displacement (x/m) | -30 | -50 | -75 | -85 | -105 | -125 | -130 | -140 | -165 | -175 | -195 | -205 | -225 | -240 |
| +15 | +20 | +30 | +36 | +45 | +45 | +50 | +55 | +58 | +62 | +66 | +70 | +74 | +80 |
| Lateral displacement (y/m) | ±10 | ±15 | ±25 | ±30 | ±45 | ±50 | ±60 | ±68 | ±7o | ±73 | ±75 | ±80 | ±85 | ±90 |
| Working Temperature (t°C) | a=100-200,b=200-300,c=300-450,d=450-500,e=500-600,f=600-700,g=700-1000 |
| Working pressure P(Kpa) | ±10~±300,if the user requires, the pressure beyond the range, can
be designed separately. |
| Flow rate | a——b | v=8——15 |
| c——d | v=8——20 |
- Applied range of non-metallic compensators (non-metallic expansion joints):
Gas turbine exhaust duct
Desulfurization system
Flue ducts and exhaust systems of various industries
Coal-fired boilers, circulating sulfurized bed boilers
Flue ducts of waste heat boilers
3. Round Non-metallic Compensator/Expansion Joint
Circular Non-metallic Compensators/Expansion Joints offer several
key advantages:
- Multi-Directional Compensation: They excel in compensating for
thermal expansion in multiple directions, surpassing metal
counterparts limited to single-axis compensation.
- Alignment Correction: These compensators effectively correct
mounting errors commonly encountered during pipeline connections.
- Noise and Vibration Reduction: Their fiber fabric and insulation
cotton inherently absorb sound and isolate vibrations, reducing
noise and vibration in systems like boilers and fans.
- Absence of Reverse Thrust: Made primarily of fiber fabric, they
eliminate force transmission, simplifying design, reducing the need
for large supports, and saving on materials and labor.
- High-Temperature and Corrosion Resistance: Selected fluoroplastics
and silicone materials provide excellent resistance to high
temperatures and corrosion.
- Superior Sealing: With a robust production and assembly system,
these compensators ensure leak-free performance.
- Lightweight and Simple Installation: Their lightweight and
straightforward structure make installation and maintenance
convenient.
- Cost-Effective: They are competitively priced compared to metal
compensators and offer better quality than imported products,
providing good damping effects.
- Enhanced Sealing Performance: Utilizing large flanges without
gaskets reduces costs and allows for direct installation.
- Long Service Life: With their durable construction and reliable
performance, these compensators offer a long service life.
