First, let's talk about the phenomenon
Many people buy non-metallic compensators, and when they open their mouths, they need a "circle" or a piece of "cloth", and take it back to weld flanges and plug insulation cotton themselves. As a result, it leaked, tore, and even disengaged within a few months. Alas, I've seen this a lot-last week a cement factory buyer complained to me on the phone that their own expansion joints had worn out in less than three months, and asked if I could just change the skin. I said it was okay for you to change the skin, but the structure you had before was simply wrong.
In fact, in engineering, the reliable way is to directly useNonmetallic compensator set— — That is, the skin (fabric fiber), insulation layer, stainless steel wire mesh, flange, guide tube, tie rod and other integral parts assembled according to the drawings. The difference between it and a single non-metallic expansion joint is like buying an assembled computer and buying spare parts to build it yourself-it seems to save money, but the compatibility and longevity are often compromised. Think about it, the computer you spell may have a blue screen, but the compensator you install can not leak?
2. What exactly is installed in the set?
Put aNonmetallic compensator setTake it apart and you'll see why you can't just make do. On the outermost side is the skin, which we call "Non-metallic expansion joint (fabric fiber expansion joint)", divided into several layers: the outer layer is weather-resistant, the middle layer is sealed, and the inner layer is insulated. Aluminum silicate fiber cotton or ceramic fiber blanket is sandwiched in the middle to resist high temperature. Further inside is reinforced by stainless steel wire mesh to prevent negative pressure suction and deflation. The two ends are flanges made of steel plates, and sometimes they have a guide tube-this thing was specifically mentioned in the question and answer, and its function is to guide the flow direction of the medium and protect the corrugated parts from being washed away. If the displacement of the pipe is large, it will also be equipped with a tie rod or limit screw to prevent over-stretching.
To put it bluntly, the set is an "all-in-one" compensation scheme, and every part has a specific purpose. Skin is responsible for sealing and weather resistance, insulation cotton is responsible for heat insulation, steel wire mesh is responsible for resisting negative pressure, guide tube is responsible for anti-washing, and pull rod is responsible for limiting. You have one less, and the system has more risk. Two days ago, a customer asked me: Can the deflector be saved? I said that you saved the guide tube, and the high-temperature smoke directly washed the inner wall of the skin, which cut off the life by more than half. Figure it out for yourself.
Third, on what occasion do you have to buy a set, and you can't make it yourself?
Is there no need to set up under ordinary working conditions? I have met customers in the cement industry where the pipeline temperature is above 800℃ and it contains a lot of dust. They previously bought their own skin field bag with rectangular non-metallic expansion joints, but it wore out in less than three months. Later, it was replaced with the set set provided by us-with wear-resistant guide tube and thickened insulation layer, which was used for more than two years. Another example is the desulfurization system, the flue gas contains acidic condensate, and the ordinary set will corrode in one or two years, so it has to be usedRubber PTFE compensatorOrPTFE compensatorFor lining, these special materials can only be vulcanized or compounded as a whole in the factory, and can't be done on site at all.
Therefore, as long as the medium temperature exceeds 200℃, there are solid particles, strong corrosion or the displacement is greater than 50mm, it is recommended to order the set directly. Don't tell me "let's try to fit it ourselves first"-the cost of trial and error is often several times the price of a set. One downtime loss is enough for you to buy dozens of sets.
4. Several pits that are easy to overturn during model selection
First, the thicker the skin layer, the better-too thick will lead to poor flexibility and reduced compensation ability. It should be calculated according to the temperature, pressure and displacement. Some customers said, "Give me the thickest one" when they came up. As a result, when the pipe was installed, the skin directly cracked. Second, the diameter and length of the guide tube are often overlooked. The specific function of the guide tube is clearly written in our question and answer. There must be enough gap between it and the inner wall of the pipe, otherwise it will get stuck by thermal expansion and contraction. Third, the adjustment direction of the tie rod nut-many installers screw the nut to the end, and as a result, the expansion joint can't be displaced, which is no different from a hard connection. Standard practice is to loosen the preload nut after installation and retain the design compensation amount. These details are generally pre-assembled and marked when the set leaves the factory, which is much more worry-free than spare parts.
Don't just look at the price. The same size set, the skin material is different, the price can be twice the difference. The outer layer is coated with silicone rubber and coated with fluororubber, and the temperature resistance grade is completely different. If you don't ask clearly, the supplier will quote you a low price, and the last one who will suffer is yourself.
5. Finally, talk about maintenance
Set up is not once and for all-skin is a wear part, and its life is generally 3 to 5 years, depending on the working conditions. Regularly check the skin surface for bulging and cracking. If so, it means that the internal insulation layer may be carbonized or the guide tube may be worn out. When replacing, you don't need to dismantle the whole pipe, just change the skin and insulation cotton, and the flange and tie rod can be reused. This is especially cost-effective in power stations and cement industries-short downtime and low labor costs.
If you have a project on hand now, you may wish to check the product list in our site: If it is a rectangular flue, look firstRectangular non-metallic expansion joint； If it is a round pipe with corrosion, look atrubber compensatorOrPTFE compensator； If you need overall matching, consult the group plan directly, and don't be an assembler yourself.