Let me give you a word: the non-metallic expansion joint is the compensator
Non-metallic expansion joints are a kind of compensator。 In the industry of pipeline compensation, the words "expansion joint" and "compensator" are mixed every day, and they all refer to the same thing-flexible joints that absorb thermal displacement and reduce vibration and noise. The names are different: "expansion joint" is biased towards structural form, while "compensator" emphasizes function. You flip through industry standardsJB/T 12235-2015 Non-Metallic Expansion JointsThe first page says clearly: "Non-metallic expansion joints, also known as non-metallic compensators". So stop worrying about the words, they're a family.
Then why is there stillrubber compensator、PTFE compensator、Fabric fiber expansion jointThese names? In fact, they are all subdivided down from the material and structure. On our stationNon-metallic expansion joints (fabric fiber expansion joints)It uses flexible materials such as silicone cloth, fluorine tape and glass fiber, which are specially used to deal with high-temperature smoke and corrosive gases. Rubber compensator mainly relies on rubber elastomer to compensate for displacement, weather resistance is poor but cheap. PTFE compensators focus on strong corrosive media, such as concentrated acid pipelines. They are all compensators in essence, but they wear different "coats" for different working conditions-different materials and different applicable scenarios.
What is the difference between non-metal expansion joints and metal expansion joints?
This question is often asked. Metal expansion joints (such as oursUniversal corrugated expansion joint、High temperature axial expansion joint) It can be compensated by the elastic deformation of the bellows, and it can bear high pressure. The pressure level is tens of MPa, but it can't bear corrosion and ultra-high temperature-stainless steel is a joke in front of wet chlorine. The non-metallic expansion joint has no metal corrugation, and depends on the flexibility of fabric and rubber, the temperature resistance can reachAbove 1000℃(Add thermal insulation layer), and it is also acid-and alkali-resistant. What's more, the displacement compensation is large-it can be eaten in both horizontal and angular directions. Two days ago, I met a customer who was doing cement factory renovation. The pipeline had a large thermal displacement and a lot of dust, so I finally chose oursRectangular non-metallic expansion jointIt is because ordinary metal bellows can't bear multi-directional displacement at all, and the rectangular cross section is more friendly to large air ducts.
Non-metal has weak pressure capacity, and the design pressure generally does not exceed 0.1MPa, so it is mainly used in low-pressure large pipelines. High-pressure applications still have to use metal bellows-each has its own strengths.
When must you use a non-metallic expansion joint? Three scenes can't run away
To put it bluntly, non-metallic expansion joints are specially prepared for certain extreme working conditions. First scenario:High temperature flue gas pipeline, such as boiler export and desulfurization tower import and export. With high temperature and sulfur in flue gas, it won't take long for metals to corrode and perforate, and the corrosion resistance and high temperature resistance of non-metals are just the right way. Second scenario:Large diameter low pressure pipelineLike the smoke duct of power plant, the diameter of two or three meters is very common. The metal bellows is expensive and laborious to install, while the non-metal is light, quick to install and convenient to maintain. Third scenario:Where vibration isolation and noise reduction are needed, such as fan import and export. Non-metallic materials have much better damping properties than metals, and can effectively absorb mechanical vibration and airflow noise. OurDesulfurization flue gas baffle doormatchNon-metallic expansion jointIt is a classic combination: the baffle door isolates the smoke, and the expansion joint compensates the thermal displacement of the pipeline. The cooperation of the two can reduce the air leakage rate to below 1%.
Don't just look at the name when you select a model. These parameters are the key
Non-metallic expansion joints are not take-all scenarios. It dividescircle、Rectangular(such as our rectangular non-metallic expansion joints), andFabric fiber type。 Four parameters are fixed when selecting:Temperature, pressure, displacement, medium corrosivity。 When sulfur-containing wet flue gas is encountered, fluorine tape material resistant to acid corrosion should be selected; High temperature dry flue gas, silicone cloth plus insulation layer is enough. In addition, don't ignore the installation details: the direction of the guide tube must be consistent with the flow direction of the medium-there is an arrow on the expansion joint, which will cause airflow erosion if installed backwards and be scrapped in advance. The tie rod nut is locked before leaving the factory, and then loosened after the pipe is installed in place, otherwise it is easy to tear the fabric layer during transportation or hoisting. This is where we areFAQ "How to adjust the expansion joint tie rod nut"It is very clear in.
Don't use non-metallic expansion joints as rubber compensators. The upper temperature resistance limit of rubber compensator is usually only about 120℃, while the non-metallic expansion joint (fabric fiber type) can reach 400℃ or even higher. The price is also quite different-it is not that others are expensive, but that the material cost is there. Wrong choice, three months of air leakage, all the money saved went into maintenance.
Having said so much, it is actually a sentence: the non-metallic expansion joint is indeed a compensator, but it is not a universal patch. Find out the working conditions, choose the right material, and install the deflector. This thing can last ten years. If you want to know the parameters in detail, you can flip through our websiteNon-metallic expansion joint (fabric fiber expansion joint)The product page is clearly marked in the data sheet.