Last autumn, Lao Li, the equipment supervisor of a cement plant, called me in the middle of the night with a burning anxiety in his voice-the man on their production lineRectangular non-metallic expansion jointIt leaked again, and the high-temperature smoke mixed with dust blew out. The temperature at the scene soared, and the inspection workers couldn't get close. This is not the first time, the seal was changed twice last year alone, and each time it didn't last three months. Old Li sighed and said, "This little thing, it looks inconspicuous. It is really deadly."
In fact, what Lao Li encountered is too common in our industry. Non-metallic expansion joints, often referred to as fabric fiber expansion joints, rely on multiple layers of flexible materials to absorb the thermal displacement of pipes. But think about it, those braids, silicone cloth, fluororubber plates stacked together, joints, lap edges, flange surfaces-there are hidden dangers of air leakage everywhere. At this time,Nonmetallic compensator sealantIs the last line of defense to fill these gaps. However, many people think that it is' just a layer of glue', so they just buy a bottle of silicone glue and paste it on it. The result is a tragedy like Lao Li.
What you think of as sealant is not the same thing as what you actually use
The sealants on the market all look similar, but their ingredients and temperature resistance are very different. For example, ordinary silicone glue, which can only carry about 150 ℃, is used in the cement industryHigh temperature axial expansion jointNearby, carbonized in an afternoon. The two-component polysulfide sealant is oil-resistant, acid-resistant and alkali-resistant, but it solidifies slowly at low temperature. When you paint it at minus ten degrees in winter, it solidifies like snot. When it dries, the daylily will be cold. There are also those ceramic fiber sealants that claim to be resistant to 1000℃. In fact, most of them are silicates with fillers, which have poor elasticity and crack when they are displaced. Tsk, do you have a headache listening to it?
What about that? Before selecting glue, you have to find out the working conditions first: What is the medium temperature? Are there any corrosive gases? Is the expansion joint axial displacement or horizontal torsion? Such asDesulfurization flue gas baffle doorThat kind of environment, with both high temperature and acidic corrosion, ordinary sealant can't bear it at all. If these parameters are wrong, no matter how good the glue is, it will be useless.
Applying glue is not squeezing toothpaste. The thicker it is, the faster it will
Two days ago, I met a colleague who made desulfurization flue gas baffle doors. He spat to me: The master on their construction site applied sealant, and he couldn't wait to squeeze a whole pipe on it, which was thick like a layer of cream. As a result, as soon as it was cured, the surface was dry and the inside was still thin. After turning on, the pressure rushed and the whole layer fell off. That's the typical pit-stepping —Nonmetallic compensator sealantIt is not the thicker the better. The standard practice is to coat it thinly two to three times, and then wait for the surface to dry each time. There's also a pit: I forgot to look at the construction temperature. In winter, when it is minus 10 degrees, you take a room temperature cured glue to apply it, and it solidifies like snot. When it dries, the daylilies will cool. What's even more outrageous is that someone used ordinary glass glue instead, and it crumbled in less than a week. You said that this matter caused trouble, saved those tens of dollars, and ended up losing tens of thousands a day after shutting down. Is it a good deal?
Exactly how often does the sealant be changed? Don't believe in advertisements, look at the feel
Don't believe the "five-year guarantee" ads. I've seen a power plant, theirRound Flap Door (Double Seal)The high-temperature-resistant sealant used is still soft after two years, without any cracks. I have also seen those in chemical plants, which age and harden in three months. The judgment criteria are actually very simple:Gently pick the sealing seam with your fingernail, if the colloid is brittle, crackled, or does not bounce back when pressed with your fingers-it is time to change. In addition, every time the machine is shut down for maintenance, shovel the old glue on the flange surface of the expansion joint clean to see if it has been corroded by the medium. I would rather spend half a day more effort than wait for it to leak before tossing.
At the end of the day,Nonmetallic compensator sealantIt is a "supporting role", but this supporting role can determine the operation cycle of the whole pipeline. Later, Lao Li changed a special high-temperature-resistant sealant and rebuilt it according to the standard process. It has been one and a half years now, and it has not leaked once. He called and said, "If I knew earlier, I wouldn't have tried to save those tens of dollars." You see, some experience has to be bought with real money. Then again, if you are now having a headache with the leakage of non-metallic expansion joints, you might as well look back to see if the sealant was not selected and applied properly. It was really worth spending a day thinking about it.