Smoke leaking from the flue expansion joint? Don't be in a hurry to order new goods, let alone copy guys and disassemble equipment when you come up. In 80% of cases, it is just that the gasket is aging, the bolts are loose, or the skin is partially broken. Follow the following three steps to save a lot of money and time.
Step 1: Find Out Where You Are Leaking
Take a flashlight and find a small mirror — yes, the kind of makeup mirror in a girl's bag. Squat down and carefully look at three positions along the periphery of the expansion joint:flange(that is, the flange that connects the pipe),weld(especially around the corner), andBellowsOntology. Where there are black ash or smoke traces are suspected leaks. Don't just look with your eyes, take a smoking can (or find some wet straw paper to stuff out the smoke) and blow it next to the suspicious location to see if the smoke is sucked in or blown away? This native method works best.
If you find smoke leaking at the flange, don't scold the manufacturer first-80% of the bolts are loose or the gasket is aging. Take a wrench and tighten the bolts diagonally. If it doesn't work, replace the gasket with the same specification. Come up and dismantle the whole section? That's paying tuition.
Step 2: Distinguish between non-metal and metal expansion joints and prescribe the right medicine
Smoke leakage from non-metallic expansion joints (fabric fibers)
Alas, this kind of skin is most afraid of heat and corrosion. If you find that the surface of the fabric is blistering, brittle, or even a hole, don't rush to call and swear. Steps: First stop the furnace to cool down, wait for the temperature to drop below 50℃, and cut off the damaged section with scissors-pay attention to cutting it into regular squares or strips, without leaving burrs. Then change the non-metallic expansion joint skin of the same material (that is, the fabric fiber expansion joint spare parts that are always available in your factory), lock it with a press strip, and the bolt torque is according to the instructions. Don't miss the checkguide tubeStill there or not — the moment that thing drops, the airflow runs straight to the skin, and the smoke will leak sooner or later. If you don't believe me, check out "Non-metallic Expansion Joint (Fabric Fiber Expansion Joint)" and "Specific Function of Expansion Joint Guide Tube" in the product information of this site, which are very clear.
Smoke leakage from metal expansion joint
That's the trouble. Take a listening stick (or a long screwdriver with a metal tip to your ear) and put it against the bellows, and stick the other end to the surface of the pipe. If you hear a hissing sound, it's a crack. Can small cracks be repaired? Ask the manufacturer first, not all materials can be welded-for example, stainless steel bellows, intergranular corrosion is faster after welding. There are too many cracks, or there are corrosion pits on the surface of the bellows, don't hesitate to replace the whole section directlyUniversal corrugated expansion jointOrCorrugated expansion joint for power station industry(If you are power stations). When it comes to the power station industry, remember to check the fatigue life-the expired bellows are like cans that have passed their shelf life and can explode at any time. Scrap when you should, don't save that little money.
Step 3: The leakage is severe and you can't stop it immediately? upper flapper door
The maintenance plan is scheduled for next month, but the bigger the smoke leak, the bigger the inspection signature is on tenterhooks. What about that? Hurry up and install it before and after the expansion jointDouble-sealed single-axis circular baffle doorOrDesulfurization flue gas baffle door。 This thing can be operated manually or electrically, and it can temporarily cut off the airflow when it is turned off, so it will last until major overhaul. And guess what? Two days ago, I met a power plant customer. They relied on this for three months, and they waited until the annual overhaul to change it, saving a whole week of shutdown losses.
The product information on this site hasRound Flap Door (Double Seal)AndDesulfurization flue gas baffle doorThe installation position and size parameters are clearly written, just follow the selection.
Finally, prevention-the secret of not repairing for ten years
tie rod nutTo adjust to the design value (how to adjust it? Flip through the FAQ "How to adjust the expansion joint tie rod nut"); On expansion jointArrow DirectionIt is necessary to align the flow direction of the medium-this is a common mistake. If the bellows is installed backwards, the force direction is completely wrong, and the life of the bellows is at least halved; Bolt torque according to instructions, do not use brute force to break.
Stop the furnace for inspection once a year, focusing on: Is there any corrosion pit in the metal bellows? Does the non-metallic skin blister and delaminate? Did the deflector fall off? Done in place, smoke leakage can't happen once in a decade. If you don't believe me, go and look at those old factories that have been used for more than ten years. They evenMetal rectangular expansion jointThey are still in use.
First check the flange and weld, and then deal with it in two kinds: non-metal/metal. If it is really impossible to go to the baffle door for emergency response, finally rely on prevention to ensure safety. Follow these three steps, smoke leaking from the flue expansion joint? Just a paper tiger.