Warranty period is not shelf life-first understand the difference between these two concepts
"How many years is the warranty period of your non-metallic compensator?" The opening is three years or five years. But in fact, most people confuse "warranty period" with "shelf life". The warranty period is the period of time during which the manufacturer promises to repair or replace the product free of charge for failures caused by manufacturing defects under normal use conditions. And the shelf life? That's the concept of food, and there is no such thing as "expired deterioration" of compensators. To put it bluntly, the warranty period is a liability contract, not a life guarantee of the product. If you buy a TV set, the manufacturer's warranty is three years. It doesn't mean that the TV will be broken after three years, right? The same goes for non-metallic compensators. Its actual service life depends on materials, working conditions and installation, which is far from the number of warranty period.
Several key factors affecting the warranty period of non-metallic compensator: material, working condition, installation
A non-metallic expansion joint (also called fabric fiber expansion joint) looks like several layers of cloth and rubber, but there are many doors inside. Let's talk about the materials first: everyone in the circle knows that the temperature resistance grades of silicone cloth, fluorine tape and polytetrafluoroethylene film are very different. It is also used in flue gas pipelines. Choose PTFE-coated glass fiber cloth and ordinary silicone cloth, and the life can be two or three times different. Let's talk about the working conditions: temperature, pressure, medium corrosiveness and displacement, each of which is a hard lever. For example, the non-metallic compensator used in the cement industry has a working temperature of 400℃, and the flue gas contains sulfur and dust. The warranty period is three years? Do you believe it? I have seen a project claiming a five-year warranty, but the band was powdered after a year and a half. Finally, installation: the installation is not aligned, the pre-stretching is not done well, and the deflector is in the wrong direction. These low-level errors can turn any warranty period into empty talk. So, don't just stare at the numbers given by the manufacturer, ask these three premises first.
What does the industry standard JB/T 12235-2015 say? Rigid rules and flexible space of warranty period
We have to talk to standards. The national standard for non-metallic expansion joints is JB/T 12235-2015, which is a hard lever in the industry. How is the warranty period stipulated in the standard? To be honest, the standard does not say one size fits all "how many years must be guaranteed". It mainly stipulates the technical requirements of product design, manufacture, test and inspection. The warranty period is usually agreed by the contract, but the premise is implied in the standard: if the product is damaged due to manufacturing quality problems, the manufacturer shall be responsible for replacing it free of charge within 18 months from the date of leaving the factory or within 12 months from the date of putting into use (whichever comes first) under the conditions of normal storage, transportation, installation and use. Got it, right? The so-called "three-year warranty" is mostly a commercial commitment made by manufacturers themselves, not a standard mandate. But there is a space for flexibility here: if the working conditions are extreme (for example, the compensator in front of the desulfurization flue gas baffle door has to withstand frequent start-stop and acid-alkali corrosion), the manufacturer can adjust the scope and exemption conditions of the warranty period through the contract terms. Therefore, when signing a contract, don't just look at the number of years, but also the exemption clause.
Actual case: Why does the same non-metallic expansion joint leak after 5 years and some after 1 year?
Two days ago, I met a power plant customer. The square non-metallic expansion joints purchased in the same batch were installed on two units. One is still running after 5 years of use, and the other is leaking in less than a year. When I removed it, I saw that the inside of the leaked ring belt was full of acid condensation, and the flange bolts were loose. What's the problem? First, the strip bolts were not adjusted well during installation, resulting in uneven local force on the ring belt; Second, the flue gas of that unit has a large moisture content and serious condensate acid corrosion, but there was no additional anti-corrosion lining when selecting materials. On the other hand, the operator regularly inspects the bolts and tightens them in time if they are loose, and the flue gas temperature is stable with little condensation. Same products, different lives. Can this blame the manufacturer's short warranty period? Can't. The warranty period is just a bottoms, and the real life span depends on the selection, installation and maintenance of the clothes worn.
What are the tricks hidden in the warranty period promised by the manufacturer? Teach you a few tricks to avoid pits
When the manufacturer opens his mouth, he shouts "three-year warranty", so you have to keep an eye on it. The first kind of tricky: the warranty is three years, but only the "ring belt" but not the "flange", or only the "main body" but not the "guide tube". The non-metallic compensator is an assembly, and the ring belt, flange, bead, guide tube and heat insulation layer are all broken. The second tricky: the warranty conditions are extremely harsh. For example, professional testing is required once a month, or the medium temperature cannot exceed 80% of the design value-in fact, the on-site working conditions simply cannot be met. The third trick: separate "warranty" and "free replacement". The promised warranty is three years, but something really goes wrong. I tell you that only the material fee will be exempted, and the freight, disassembly, installation and downtime losses will be ignored. How to avoid pits? When signing the contract, write these articles clearly: 1) What parts are covered by the warranty; 2) Whether the free repair includes labor and freight; 3) Response time of failure during warranty period; 4) Whether the disclaimer clause is reasonable. For example, some manufacturers write in the contract that "the damage caused by media corrosion is not covered by warranty", so the compensator used on desulfurization flue gas pipeline is equivalent to no warranty.
How to prolong the actual service life of non-metallic compensators? More reliable than staring at the warranty period
It is better to pay attention to extending the actual service life than to talk about the warranty period of non-metallic compensators from three years to five years. How to do it? Three points: 1) Give enough wealth when selecting models. For example, if the design temperature is 400℃, don't choose materials with just the right temperature resistance of 400℃, and leave a margin of 50℃. Pressure is also true. For working conditions with large fluctuations, select a higher pressure grade. 2) During installation, please ask the manufacturer's technicians to be present for guidance, especially the large-diameter rectangular expansion joint, pre-tensioning, bolt torque and direction of the guide tube, one step is wrong, one step is wrong. 3) Regular maintenance after use. Check once a quarter whether the surface of the ring belt is cracked, blistered and worn, whether the flange bolts are loose, and whether the condensate discharge hole is blocked. Problems are found to be dealt with in time, and minor repairs can last a year or two. To put it bluntly, the non-metallic compensator is a consumable, don't expect it to be done once and for all. Instead of struggling with the warranty period on paper, it is better to make routine maintenance solid.