Corrosion Problem: Flue Environment Crueler Than You Think
The flue metal expansion joint seems strong, but when it comes to the smoke of power plants and steel plants, it will show you a look in minutes. Those sulfides and chlorides in the flue gas, plus high temperature and humidity, are a proper corrosion package. Stainless steel bellows? The 316L is also useless. Two days ago, a customer complained to us that they usedCorrugated expansion joint for power station industryAfter only half a year of operation, pitting corrosion appeared on the surface of the bellows, and it leaked directly in two months. And guess what? When I remove it, I see that the inner wall is full of holes-caused by acid dew point corrosion.
What's even bigger is that there is often condensed water in the flue, which mixes with acidic gas to form dilute sulfuric acid. The wall of the corrugated pipe of the metal expansion joint is thin, generally 1-3mm. In this corrosive environment, the thinning speed is much faster than you think. If the maintenance cycle in the factory can't keep up, it will be scrapped in advance. You say this isn't called a flaw? Then what counts?
Dust accumulation problem: Dust cleaning cost soars, structural defects are the main cause
The corrugated structure of the metal expansion joint looks telescopic, but it is also a natural "ash storage groove". The dust particles in the smoke, particularly fine, can't come out after entering the ripple gap. With a long time, ash accumulates and fouls, the bellows loses its elasticity, and the compensation ability plummets. What's more annoying is that you can't clean it online-shutdown for dust cleaning? Losing hundreds of thousands a day.
ContrastRectangular non-metallic expansion jointThe inner wall is smooth, and there is no dust hanging. Even if there is dust accumulation, just flush it with water. What about metal expansion joints? When cleaning dust, you have to remove the insulation and sheath, and flush it slowly with a high-pressure water gun, which may not be cleaned. Who will calculate this hidden cost when purchasing?
Fatigue Cracking: Frequent Start-Stop and Vibration, Can Bellows Hold It?
Who in the current crew still runs at full capacity 24 hours a day? Peak shaving and start-stop are becoming more and more frequent. Every time the corrugated pipe of the metal expansion joint expands and contracts, it is subjected to alternating stress. Low-cycle fatigue life is a limited number of times-don't believe the manufacturer's target "100,000 times", that is the ideal state. Under actual working conditions, coupled with vibration and pressure fluctuation, someUniversal corrugated expansion jointIt cracked in less than two years.
The crack appears at the trough, because that is the stress concentration zone. It starts as micro-cracks, slowly expands, and finally penetrates. The leaked smoke is high-temperature, toxic, and will burn out the equipment next to it. Tsk, if this happens on a critical pipeline, think about the consequences for yourself.
What about that? useHigh temperature axial expansion joint？ That also depends on the design. If it is a flue that starts and stops frequently, consider it honestlyNon-metallic expansion jointFabric fiber, people are not afraid of fatigue, vibration can also absorb.
One wrong installation, all dry behind: How demanding are the requirements for pipe alignment and brackets
The installation of metal expansion joints pays attention to "the right time, place and people". Pipe centering deviation by one or two millimeters? Okay? Wrong! If the deviation is large, the force of the bellows is uneven, and it is stretched and compressed at the same time, so the life is folded in half. There is also a bracket, and the guide bracket and the fixed bracket must be matched well. We ran into a cement factory that used usMetal Corrugated Expansion Joints in Cement IndustryHowever, the fixed bracket was not set according to the drawings during the installation. As a result, the pipeline was displaced during the trial operation, and the bellows was forcibly torn.
In contrast,rubber compensatorOrRectangular non-metallic expansion joints are not so delicate when installed, and the amount of misalignment allowed is large, and they can be fine-tuned when installed wrong. Metal expansion joint Fake it wrong once, and it's all lessons behind.
Ledger can't just look at purchase price: real cost comparison
When purchasing price comparison, the quotation of metal expansion joint is often low. But what about the general ledger? Take the flue of the power plant as an example. The metal expansion joint is replaced once every 2-3 years, and the cost is doubled in batch, plus the shutdown loss, cleaning labor and maintenance cost. WhileRectangular non-metallic expansion jointOrrubber compensatorThe purchase price is higher, but the life may be 5-8 years, and there is no dust cleaning.
There was a desulfurization project the year before last. The original design was all metal expansion joints. After one year of operation, the corrosion problem broke out. Replace withDesulfurization flue gas baffle doorWith the non-metal compensator, it has been four years now, and there is no problem at all. Which do you say is a good deal?
To put it bluntly, the disadvantage of flue metal expansion joint is not that it can't be used, but that it depends on the working condition. If you don't count these flaws in the selection, you will have to make up lessons sooner or later. Those who know the business will evaluate comprehensively; Only focus on the budget, pay the tuition first.