A non-metallic compensator is a skin? Stop mixing up!
Is a non-metallic compensator a skin? If you go to the maintenance site and ask around, eight out of ten old masters may point to the layer of cloth and say, "Isn't this the skin?" But if you understand it this way, then the procurement and design links will lead to a big mess. Today, let's get this straight.
Find out one thing first: What exactly is a non-metallic compensator?
Start with the product name. Non-metallic compensators, also known asNon-metallic expansion joint、Fabric fiber expansion jointDefinitely not a single layer of fabric. It is a set of multi-layer composite flexible pipeline compensation device, which is specially used to absorb thermal displacement, reduce vibration and noise. To put it bluntly, it is a "system", not a "part". If you just take a skin to replace it, that's called changing the coat, not the compensator.
Two days ago, I met a customer, and urgently called and asked, "Your non-metallic compensator, if the skin is broken, can you only change the cloth?" I said yes, but I have to find out which layer you changed first. He was stunned: "Isn't it just a layer of skin?" – you see, this is the typical misconception.
Take it apart to see the interior
Take a complete non-metallic compensator apart, and you'll find something inside:
- outer layer: Skin (temperature-resistant and corrosion-resistant fabric layer), which is the "skin" that everyone is most familiar with.
- intermediate: Heat insulating cotton, sealing film. Insulating cotton is responsible for blocking high temperature, and sealing film prevents smoke from leaking out.
- inner layer: Wire mesh, flange frame. Wire mesh is used to enhance overall strength, and flanged frames are responsible for hard connections to pipes.
So, the skin is just the outermost layer of "skin", which is equivalent to a coat. There are also cotton-padded jackets, underwear and skeletons inside. When you say a person wears a down jacket, can you say that a down jacket is a person? A truth.
Function of skin and material selection
Temperature, corrosion, aging. Common materials are silicone rubber, fluororubber, PTFE fabric. The material selection must be based on the working conditions:
- Silicone rubber skin: Temperature resistance around 200℃, suitable for general smoke environment.
- Fluorine rubber skin: Temperature resistance 250-300℃, acid and alkali resistance, commonly used in desulfurization system.
- PTFE fabric: Higher temperature resistance, extremely strong corrosion resistance, but also expensive.
However, it is easy to cause problems by changing the skin without changing the overall structure. Take a real case: a power plant only changed the skin, and did not check whether the insulation cotton in the middle was hardened. As a result, after three months of operation, the internal insulation failed, the outer flange was baked and deformed at high temperature, and the whole set of equipment was scrapped. You say it's a pity or not?
Non-Metallic Compensator vs Skin: Don't Confuse It
The compensator is a complete set of components, including the frame, guide tube, insulation cotton, bead, bolts, and so on. The skin is just a replaceable consumable in it. It is true that only the skin can be changed when replacing, but the design selection must be based on the overall performance.
For example, you bought aRectangular non-metallic expansion jointThen its compensation amount, temperature resistance grade and pressure grade are all calculated for the whole structure. Looking at the skin thickness alone (such as 2mm or 3mm), the reference value is limited. Just like buying a car, you can't judge the performance of the whole car just by looking at the tire tread thickness, can you?
Why do people often call it wrong?
Because the repair site often only changes the skin. Over time, everyone thought that "compensator = skin". In addition, many small manufacturers sell skin as a standard product, and writing "skin compensator" on the drawing deepens the misunderstanding.
In fact, we have bothNon-metallic expansion joint (fabric fiber expansion joint)This typical representative, there are alsorubber compensator、Rubber PTFE compensatorAnd other variants, but their core advantages are in multilayer composite structures. Single-layer skin simply can't withstand the high-temperature and high-pressure smoke erosion.
Purchase recommendations
Don't just focus on the thickness and material of the skin, ask these points clearly:
- Insulation thickness: At least 50 mm or more, otherwise the heat bridge effect will burn out the flange.
- Frame Material: Carbon steel or stainless steel? Is the surface anti-corrosion treatment done?
- Installation dimensions: The flange bolt hole distance and the pipe center are high, all of which can't be wrong.
Standard referenceJB/T 12235-2015。 The overall temperature resistance and compensation amount are the key indicators. For example, if your working temperature is 400℃, you can't just look at the nominal 450℃ of the skin and place an order. You have to confirm whether the heat insulation layer and the sealing film can match.
If the next time someone asks "Is a non-metallic compensator a skin?", you can ask him rhetorically: "Then do you think people are clothes?"-this analogy is rough, but not rough.