Flue through stairs? The expansion joint is chosen so as not to step on the pit
Seriously, the term "flue for stair expansion joint", at first glance, sounds a bit twisty. However, anyone who has worked in the renovation of power plants, cement plants or boiler rooms knows that the flue pipeline has to cross the stairwell or walk close to the stairs. The space is inherently narrow, and the pipeline has seven turns and eight turns, so the thermal expansion and contraction have to be controlled. The number one task of the expansion joint (also called the compensator) here is to absorb displacement and relieve stress. The ones on our site, such asUniversal corrugated expansion joint、Metal rectangular expansion joint、Non-metallic expansion jointIn principle, they all do this job. However, the angle of the stairs is tricky, and it can't be crossed by just screwing one up.
Two days ago, I met a customer. A flue was stuffed under the stairs of the factory building, and a bargain was used. It leaked in less than half a year. When asked, the tie rod nut was not removed during installation, which is equivalent to white installation. You say it was wrong or not?
What is so special about the location of the stairs? Three hard bones
First, the space is small.That big tie rod expansion joint in an empty factory building, you stuff it under the stairs? There are no doors. Second, the displacement direction is chaotic. Not only does the pipe expand and contract axially, but it may also twist laterally due to the corners of the stairs. That's when we have to considerCompound hinge transverse expansion jointOrRotary compensator— — Both of these are hung out on our station, specifically to deal with multi-directional displacement. Third, the temperature is high. Flue gas hundreds of degrees Celsius is the norm, ordinary rubber compensator can't hold it, have toHigh temperature axial expansion jointOrPTFE-lined hoseIn order to withstand thermal corrosion.
Don't be blind in choosing models, look at these four scenarios
The flue is a rectangular section? PriorityMetal rectangular expansion jointOrRectangular non-metallic expansion jointWhich is temperature-resistant, corrosion-resistant, and can absorb lateral displacement. What about the circular pipe,Universal corrugated expansion jointOrStraight pipe pressure balanced expansion jointAll right, but the displacement must be calculated accurately-if you calculate less fatigue cracking of the bellows, if you calculate too much, you will suffocate the bracket. If the stairs are cornered and the space is stretched thin,Compound straight pipe bypass pressure balanced expansion jointOrCurved tube pressure balance expansion jointIs the savior. I have all these models on my station. Don't buy knockoff goods cheaply. It's too late to cry if the models don't match the later period.
Installation pit checklist: pull rod, deflector, fire protection
Installed pits, each deeper than the last. First of all,Expansion joint tie rod nut must be removed。 Many workers try to save trouble and don't dismantle it, which is equivalent to treating the expansion joint as a rigid short joint. Where does the compensation come from? The FAQ on our station specifically said that the function of the tie rod is to transport and fix it, and it must be loosened after installation. Secondly,The direction of the guide tube should be aligned with that direction of the medium flowThe arrow is clearly marked. If the arrow is reversed, it will impact the bellows and accelerate fatigue. Also, stairwells usually have fire protection requirements.Non-metallic expansion jointWhen, be sure to confirm that the fiber fabric material is flame retardant-don't fail to pass the acceptance when the time comes. When passing through walls or stair platforms, it is best to add a fixed bracket. Don't let the expansion joint bear load. It is only responsible for absorbing displacement, not structural parts.
Old after-sales question: Why does it leak in two years?
Many people feel it once and for all after installing it, and it leaks after two years. There are no more than two reasons: either the selection is too small, and the fatigue cracking of the bellows at high temperature; Either the pre-stretching was not done well during installation, and the actual displacement exceeded the limit. And guess what? As mentioned in the FAQ on our station, the design life of expansion joints is usually 10-15 years, but it is common to scrap them after three to five years because the working conditions are poor and the maintenance is not careful. For peace of mind, go straight toExternal pressure single axial expansion jointLong life and convenient maintenance-the outside of the wave tube is wrapped with a shell, and the sundries can't get in, so the inspection is easy.
The last big truth: Don't try to be cheap
Flue leakage is no trivial matter. High-temperature smoke is spewed out, and the stairwell is an evacuation passage. You know the consequences. The products on our site, such asDouble-sealed single-axis circular baffle door、Manual plug-in insulation door, all validated in power stations and cement industries. If your stair flue space is too tricky, such as large pipe diameter and high wall thickness requirements, you can find manufacturers to customize non-standard parts, such asLarge diameter thick wall expansion jointOrTapered expansion joint。 Remember: expansion joint + tie rod + guide tube, the three-piece set is stable. Otherwise, the money spent on later repairs is enough for you to buy two sets of genuine products.