1. Let's start with the structure: What is the difference between non-metallic waveform compensator and metal expansion joint?
Many people think "non-metal" is a cheap substitute when they hear it, but it's just the opposite. Non-metallic waveform compensator (also called in our stationNon-metallic expansion jointOrFabric fiber expansion jointInstead of a metal bellows, the main body is a composite of multiple layers of flexible materials-usually including silicone/fluororubber coated fiberglass cloth, PTFE film, ceramic fiber insulation, plus stainless steel wire mesh reinforcement. This structure gives it a natural ability that a metal expansion joint can't do:Barely transmitting thrust。
Think about it, although the metal bellows can absorb displacement, it will still produce elastic reaction force itself, which has additional requirements for the pipe support; The non-metallic compensator depends on the flexible deformation of the fabric, and the reaction force is very small, so it is especially suitable for those thin-walled pipelines or equipment interfaces that can't bear large thrust. Two days ago, there was a customer who made a dust removal system. The wall thickness of the pipe was only 3mm. Every time he drove with a metal expansion joint, the bracket was crooked and replaced with oursRectangular non-metallic expansion jointThe problem is solved directly.
2. Temperature resistance and corrosion resistance: What working conditions must it be?
Strong acid and alkali corrosion and ultra-high temperature flue gas. But nonmetallic waveform compensators happen to play in both fields. From our stationRectangular non-metallic expansion joint、rubber compensator、Rubber PTFE compensatorAll are targeted designs: the outer layer is made of polytetrafluoroethylene (PTFE) or special fluororubber as an anti-corrosion barrier, and the inner layer is made of ceramic fiber or aluminum silicate cotton as heat insulation. The long-term temperature resistance can be above 1000℃ (such as the smoke duct of power plants).
There is a customer in the cement industry. The temperature of the flue gas at the tail of their kiln fluctuates greatly, and it also contains sulfur. The metal expansion joint is perforated in one year. Replace it with oursMetal Corrugated Expansion Joints in Cement Industry？ Of course, it works, but the cost is high-later, non-metallic expansion joints were used, which saved half the cost and prolonged the life. The principle is simple: the non-metallic material itself is corrosion resistant and does not produce stress corrosion cracking.
3. Displacement compensation ability: large displacement and multi-direction are its home field
Metal expansion joints are usually good at axial displacement, while lateral and angular displacement depend on complex structures (such as compound hinge type and universal type). What about non-metallic waveform compensators? It is itself a piece of "soft connection" that can absorb axial, lateral and angular displacements simultaneously-as long as the structure is properly designed. For example, ourRectangular non-metallic expansion jointIt is often used in rectangular flues of power plants and steel plants, and can compensate for the deviation in various directions caused by thermal expansion and contraction.
Moreover, its compensation amount can be made very large, and some can reach more than 100mm. To reach this amount, a metal expansion joint of the same size may have to be made into several waves or even with a tie rod. So you have to ask what is the biggest feature of non-metallic compensators? One word:soft。 It can resist large displacements and is not afraid of multiple directions.
4. Hidden advantages of installation and maintenance: light, easy to change, and not afraid of installing wrong
Everyone who does engineering knows that the fault tolerance rate of equipment installation is very important. Non-metallic waveform compensators are usually 30%-50% lighter than metal expansion joints of the same caliber, which can be moved by one person, and are convenient for on-site welding or flange connection. More importantly, in case the pre-stretching is not accurate during installation, or the pipeline deviates, the forced adjustment of the metal expansion joint may screw the bellows; The elasticity of non-metal is good, and it can still work if it is slightly biased.
And in our product structure, likerubber compensatorAndNon-metallic expansion jointThey are all modular designs, and the inner lining, insulation and outer cladding can even be replaced separately-which layer is broken and which layer is replaced without dismantling the whole pipe. Don't underestimate this. The maintenance window period of power plants is so short. It may take half a day to weld a metal expansion joint. Once the non-metal one is tightened with bolts, it will take half an hour to get it done.
5. The easiest pit to step on when selecting a model: don't treat non-metals as a panacea
Having said so many advantages, I have to pour some cold water. Non-metallic waveform compensators do not work everywhere. First of all, its pressure bearing capacity is inherently weak, and it is generally used in low-pressure systems (usually below 0.1MPa, and higher special designs can reach about 0.5MPa). If you are steam pipes, high pressure oil pipes, honestly choose metal- -like oursUniversal corrugated expansion jointOrHigh temperature axial expansion joint。
Secondly, the fatigue life of non-metallic compensators is not as good as that of metal bellows-the fabric layer always has an aging period, and the general design life in the industry is 10-15 years, while the metal expansion joint can reach more than 20 years under ideal working conditions. In addition, some media contain hard particles (such as pneumatic ash transportation pipelines), and high-speed scour will wear the fabric. At this time, wear-resistant lining or direct metal has to be added. To sum up: When selecting the model, see the four parameters of pressure, temperature, medium and displacement clearly. Don't just listen to "non-metal is cheap" and use it indiscriminately. We have so many product lines in our station, fromNon-metallic expansion jointToHigh temperature axial expansion joint、Universal corrugated expansion joint, is to let you match on demand.
All right,What are the features of non-metallic waveform compensator?Simply put, it is: flexible structure, high-temperature corrosion resistance, multi-direction large displacement, worry-free installation and maintenance, but low pressure and limited life, so you must look at the working conditions when selecting the type. If you have a specific project on hand and aren't sure which one to use, feel free to flip through the product page on our site- -Rectangular non-metallic expansion joint、rubber compensator、Rubber PTFE compensatorThey all have detailed parameters, so just take your seat.