Find out one thing first: What exactly is an ultra-wide non-metallic compensator?
To put it bluntly, it is a kind of rectangular non-metallic expansion joint with a particularly large width, which is usually used in large-diameter square tubes such as smoke ducts and desulfurization pipes. Tell us what we said in the stationRectangular non-metallic expansion jointAndNon-metallic expansion joint (fabric fiber expansion joint)It's a thing. Just the width is beyond the regular size, like two or three meters or even wider. This kind of big guy, ordinary metal compensators can't handle it-high cost, stress concentration, and easy fatigue fracture. Think about it, how powerful is a square tube several meters wide when it expands and contracts by heat? The metal bellows carried hard and cracked within a few years.
The first hardcore action: absorption of multidimensional displacements, especially lateral and angular displacements
Everyone knows the thermal expansion and contraction of pipelines, but the displacement of ultra-wide section is not only axial expansion and contraction, but also lateral swing and torsion. And guess what? The fabric fiber layers of non-metallic compensators are inherently capable of eating this composite displacement, without relying on complex structural design like metal bellows. Two days ago, I met a customer in the cement industry, saying that his pipeline interface was always misaligned. After changing the ultra-wide non-metallic compensator, the problem was directly solved-because it was flexible enough to absorb the displacement caused by installation error and foundation settlement. To put it bluntly, it's like a flexible joint, which twists when the pipe is crooked, not a hard top.
The metallicCompound hinge transverse expansion jointDoesn't it also absorb lateral displacement? Yes, but it costs a lot. The structure is complicated, the price is expensive, and the installation accuracy is extremely high. What about ultra-wide non-metallic compensators? It is done with a fabric loop strap directly, and it is okay to deviate by a few millimeters during installation. The flexibility is there.
The second key function: corrosion resistance, high temperature resistance, the 'savior' of bad working conditions
Many ultra-wide pipelines take high-temperature flue gas or waste gas containing sulfur and acid, and the temperature can reach 600℃ or even higher. Metal expansion joint In this environment, the surface anti-corrosion coating is finished as soon as it peels off. However, the non-metallic compensator uses multi-layer composite fabrics such as silica gel cloth, fluororubber and glass fiber, which are both temperature-resistant and acid-alkali corrosion-resistant. The one in our stationNon-metallic expansion joint (fabric fiber expansion joint)It is especially used in the desulfurization flue gas baffle door system, and the effect has a good reputation. Just takeDesulfurization flue gas baffle doorSpeaking, the sulfur content and moisture in the flue gas are high, and the metal parts will rust out in half a year. The non-metallic compensator is still fine after three years of use. Of course, the material selection depends on the temperature: over 200℃, aluminum silicate fiber cotton must be added, and if there is corrosion, fluororubber or PTFE lining must be added.National Standard for Non-Metallic Expansion Joints JB/T 12235-2015There are detailed regulations in it, so the acceptance is correct according to that.
The third easily overlooked role: vibration and noise reduction
When the duct is running, low-frequency vibrations generated by the fan and airflow can travel throughout the system along the rigid connection. The ultra-wide non-metallic compensator itself is a 'soft connection', which can absorb vibration energy and reduce noise by the way. For example, if a non-metallic compensator is not installed in the smoke duct of the power station industry, the vibration can loosen the bracket. After installation, the life of the equipment is extended by at least 30%. As forCorrugated expansion joint for power plant industry— That's another matter. Metals are less effective at damping vibrations than non-metals. This is determined by the properties of the material. The metal bellows relies on elastic deformation to reduce vibration, but it is easy to resonate under low frequency vibration; Non-metallic fabric layers are porous structures that inherently damp vibrations. If you don't believe me, listen to it. Pipes with non-metallic compensators are at least 5-8 decibels lower in noise.
thatrubber compensatorCan't dampen the vibration? Yes, but the rubber is not resistant to high temperatures, and it is soft when it exceeds 100 ℃, and the strength is not enough when the cross section is ultra-wide. The non-metallic fabric fiber band, with glass fiber as a skeleton inside, is soft and tough, which is the right solution.
Compare metal compensators and you know the irreplaceability of non-metals
Metallic (such asUniversal corrugated expansion jointOrHigh temperature axial expansion joint) Suitable for scenarios dominated by high pressure, small diameter and axial displacement. However, the shortcomings of metal in ultra-wide cross-section low-pressure pipelines are too obvious: first, the cost is high, thick-walled stainless steel plates are needed, and the welding amount is large; Second, the guide tube is easy to wear out and has a short life. What about non-metallic compensators? Light weight, simple installation and convenient maintenance-if it is broken, just change the fabric loop strap directly without moving the whole pipe. Of course, it cannot bear pressure and is only suitable for low-pressure systems, which is something to keep in mind. So don't take it insteadDirect buried (fully buried) type expansion jointThat's high-pressure pipeline work.
We have a client who doesAir-cooled island vacuum pipeThe double-hinge expansion joint is used, which is metal because the vacuum system has pressure requirements. But if it is an atmospheric flue, non-metal is the optimal solution.
How do you choose in practice? Remember Three Principles
Look at the temperature, the medium, and the displacement. If the temperature exceeds 200 DEG C, the fabric layer should be high-temperature resistant aluminum silicate fiber cotton; The medium is corrosive and must be lined with fluororubber or PTFE; If the displacement is mainly transverse, the compensation amount of non-metals is much greater than that of metals. In addition, pay attention to protection when installing, don't let sharp objects scratch the fabric surface. In our station aboutService life of expansion jointThere are also detailed instructions. Install it according to the specifications and use it for ten or eight years without any problem.
Finally, the ultra-wide non-metallic compensator is not just a telescopic pipe, but a flexible joint that can flex and stretch in the whole pipe system-without it, no matter how thick the flue is, it can't withstand the repeated tossing of thermal expansion and contraction. Think about it, a square tube tens of meters long, the temperature rises from normal temperature to 400℃, and the expansion amount can reach tens of millimeters. For a hard connection, either the pipe is bent or the flange bolts are pulled off. With this flexible joint, all displacement is absorbed and the system is safe.