What exactly is a non-metallic compensator? How is it different from a metal compensator?
Don't rush to flip the standards yet. Simply put,Non-metallic compensator(also called non-metallic expansion joint, fabric fiber expansion joint) is a thing that relies on non-metallic skin to absorb the thermal displacement of pipes. Its core feature is that it does not deform by metal bellows, but by stretching and compressing flexible materials (such as silicone cloth, fluororubber and polytetrafluoroethylene). If you look through the product list of this site, you haveNon-metallic expansion joint (fabric fiber expansion joint)、Rectangular non-metallic expansion joint、rubber compensator、Rubber PTFE compensatorThese, all belong to this broad category. Compared with the metal compensator, its pressure is indeed weaker, but it can't keep up with the metal horse in compensating for large displacement, corrosion resistance, vibration and noise reduction.
Looking at the structure when disassembled: skin, insulation layer and frame are indispensable
A standard non-metallic compensator consisting of a flexible skin, internal insulation cotton (aluminum silicate fiber felt or the like), stainless steel wire mesh and a metal frame. The skin is the core, and the common ones are silicone rubber coated glass fiber cloth and polytetrafluoroethylene film composite layer-in the stationRubber PTFE compensatorThat's how it works. The more skin layers, the stronger the temperature and pressure resistance.Rectangular non-metallic expansion jointIt is mostly used for rectangular flue, and the frame should be strengthened to prevent deformation. And don't forget,The national standard for non-metallic expansion joint is JB/T 12235-2015There are specific requirements for the tensile strength and elongation at break of the skin, so remember to check when selecting the type.
4 hardcore features: large displacement, corrosion resistance, noise reduction, easy installation
First, the compensation displacement is large.A wave of metal expansion joint can only compensate a few millimeters, and the axial compression of non-metal can reach more than 50mm, and the lateral displacement is no problem. Think about it, the thermal expansion and contraction of the pipe is tens of millimeters, and several waves have to be strung with metal, but one can do it with non-metal.
Second, corrosion resistance and temperature resistance.The fluororubber skin can carry about 200℃, and with PTFE coating, it can also resist acid and alkali smoke — —Desulfurization flue gas baffle doorFor the pipe connected behind, a non-metallic compensator is just right. Two days ago, a customer of a cement factory said that they used rectangular non-metallic expansion joints at the end of the kiln, and they had not had any problems for three years. Tsk, this is an example of choosing the right material.
Third, the vibration and noise reduction effect is good.The flexible structure naturally absorbs vibration, and the fan outlet can save a bunch of vibration damping pads with it. And guess what? Some power plants directly install non-metallic expansion joints at the inlet and outlet of induced draft fans, and the noise is directly reduced by more than ten decibels.
Fourth, installation and maintenance are hassle-free.Lightweight, one person can carry it, the flange is directly bolted, and if it is broken, only change the skin without moving the pipe. Is it less worry than dismantling the metal bellows for half a day?
Playing the ring with the metal compensator: who is suitable for what working conditions?
Metal compensators (e.g.Universal corrugated expansion joint、High temperature axial expansion joint) High pressure resistance, long life, suitable for steam pipeline, high-pressure oil pipe. The shortcomings of non-metals are also here-you have to be cautious when the pressure exceeds 0.1MPa, which is usually used in low-pressure flues, air ducts and dust removal pipes. But it can carry large angles of twist and deflection, and the metal one cracks when it is twisted. In addition, the non-metal thrust on the pipeline is small, the bracket design can be simplified, and the owner can save a sum of money. So you see,Corrugated expansion joint for power station industryIt is mostly used for main steam, whileNon-metallic expansion jointIt is used in desulfurization and the import and export of induced draft fans. How to choose? Don't just focus on pressure, look at working conditions and demands.
The 3 Details of the Most Easiest Rollover in Selection
One is temperature. Don't just look at the medium temperature, but also the radiant heat and heat dissipation conditions. If the surface temperature of the skin exceeds 250℃, thermal insulation layer must be added. The second is medium corrosiveness. The flue gas below the acid dew point contains sulfuric acid, so it can be usedPTFE compensatorOrdinary silicone cloth can't last for two months. The third is the installation direction.The direction of the guide tube of the non-metallic compensator must be consistent with the flow direction of the mediumOtherwise, the windward side will bulge and tear. How do you adjust it? Refer to Q&AMethod for adjusting the nut of the tie rod of the expansion jointHowever, non-metal generally has no tie rod, and all relies on flange bolts to compress it. Finally, a reminder: the service life of non-metallic compensators is usually 3-5 years. Ultraviolet aging should be considered for open-air installation, and space for replacement should be reserved during model selection. After such combing, are the characteristics of non-metallic compensator products much clearer? The next time you choose a model, you have a spectrum in your heart.