Have you thought about the expansion joint where the SCR enters?
The SCR imported flue expansion joint sounds like an obscure gadget, but if you choose the wrong one, it's enough for you to drink a pot. Let's talk about the working conditions first-high temperature, often three or four hundred degrees Celsius; With a lot of dust, the flue gas also contains corrosive gases such as sulfur dioxide. Just take an ordinary bellows and stick it in? I have seen several projects do this, so it is cheap to save trouble. As a result, it leaked in less than three months, and it was shut down for maintenance. The cost is enough to buy ten serious expansion joints. This stuff is not a general-purpose piece, we have to prescribe the right medicine.
Metallic or non-metallic? Don't slap your head yet
The most troublesome thing about selection is how to choose between metal and non-metal. We have one on our siteNon-metallic expansion joint (fabric fiber expansion joint)The temperature resistance and corrosion resistance are quite good, and the installation is light, which is especially suitable for the environment where dust and corrosion coexist. But if the displacement of the pipe is particularly large and the pressure is high, thenMetal rectangular expansion jointOrCorrugated expansion joint for power station industryProbably more reliable. Don't just look at the price-temperature, pressure and displacement direction, these three parameters are indispensable. For example: There is a power plant project, and the design value of the lateral displacement of the pipeline is 50mm. As a result, the picture is cheaper than non-metal, and the fabric layer is torn after half a year. Later, I changed the metal rectangular expansion joint, and I ran for two years and nothing happened. To put it bluntly, the working condition parameters determine everything, so don't listen to the sales blindly.
The pits in the installation, each deeper than the last
The expansion joint bought back has the arrow direction on it, which is not decorative-the guide tube points to the sign. Install backwards, the guide tube can't play the role of diversion, and the flue gas directly washes the bellows, which won't take long to wear out. Another, how to adjust the tie rod nut? When leaving the factory, it is generally locked to prevent transportation deformation. After installation, it must be loosened to the design position, otherwise the expansion joint has no room to move at all, which is no different from welding dead. A few days ago, a customer called and asked: After the expansion joint is installed, the pipe vibrates heavily. What's going on? When I looked at it in the past, the thread of the tie rod nut didn't move-it quickly loosened to the specified stroke, and the vibration immediately disappeared. Also, the function of the pull rod is to limit the position and bear the pressure thrust. When adjusting, refer to the installation instructions given by the manufacturer, and don't twist it by feeling. Oh, yeah,The direction of the arrow of the expansion joint refers toMedia flow direction, install backwards is not only a problem of wear, serious will directly lead to seal failure.
Deflector: the most overlooked "life-saving" piece
The SCR inlet flue has a fast wind speed and is simply a natural sandblasting machine with ash particles. If the thickness of the guide tube is not enough or the material is wrong, it will be a matter of time before it wears out. You knowSpecific Function of Expansion Joint Guide TubeWhat is it? To put it bluntly, it is to use a wear-resistant steel plate to guide the high-speed airflow away and protect the bellows inside from being washed away. It is recommended to use 1Cr18Ni9Ti or thicker stainless steel with a thickness of at least 4mm starting. In order to save money, some manufacturers use ordinary carbon steel, which rust out in one or two years, and the bellows are directly exposed to the smoke, which greatly reduces their life span. When selecting the model, be sure to confirm the material and thickness with the manufacturer, and write this requirement in black and white into the contract.
Check regularly, don't expect to do it once and for all
Everything will be fine when the expansion joint is installed? Beautiful thought. The life span has too much to do with the working conditions.National standard for non-metallic expansion jointsJB/T 12235-2015 contains test methods and inspection rules, but that is only the minimum requirement. Actual life depends on your smoke composition, temperature fluctuations, start-stop frequency. It is recommended to check every six months: to see if the non-metallic fabric has blistered and aged, and if the metal corrugation has cracked. To be honest, change if you need to change, don't hold on. An expansion joint is not much money, and the loss of one day of downtime is enough for you to buy a bunch of spare parts. Because of the tight maintenance budget, some projects are dragged out, and as a result, the flue body is worn out, and the maintenance cost costs hundreds of thousands more.
Small accessories, big price
After all, although the SCR imported flue expansion joint is a small component, if it is selected correctly, the system will run steadily for several years; Wrong choice, enough for your headache. If you are not sure, ask the manufacturer directly for a plan-let them recommend it according to your drawings and working conditions, which is much more reliable than patting your head. The product line in our site is very complete, fromNon-metallic expansion joint (fabric fiber expansion joint)ToMetal rectangular expansion joint、Corrugated expansion joint for power station industryAll of them, which can be matched according to actual parameters. Remember: Don't try to be cheap, don't save that little consultation time. The expansion joint fails, and the cost of shutdown and maintenance can be much higher.