Getting Your Glass Heating Right: The Truth About Ultra-Long IR Units
Most infrared lamps are pretty short. That’s fine for small jobs, but when you’re running a massive glass tunnel kiln, short lamps are a headache. If you just overlap a bunch of small ones, you end up with “cold spots”—those annoying gaps in temperature that can ruin a glass sheet before it even hits the forming stage. That’s why we build heating units that stretch past 2 meters. It’s about getting that temperature perfectly even across the whole surface.
The Battle Against Voltage Drop
Here’s the thing: when you go long, voltage drop becomes your biggest enemy. You can’t just stretch out a standard filament and hope for the best. If you do, the center of the lamp will burn out while the ends stay lukewarm. It’s a waste of money and a recipe for downtime. Instead, we tweak the wattage and voltage across the entire length of the quartz tube. We do the math upfront so the heat density stays the same from one end to the other. Just a heads-up: these long-run units pull a lot of amperage when they first kick on, so make sure your power supply can actually handle the hit.
Keeping Things Straight (and Hot)
When quartz gets screaming hot, it wants to sag. To stop that, we use heavy-wall quartz glass. It keeps the tube rigid and stable, even when it’s running 24/7. We line these units up in a tight sequence to create what I call a “wall of heat.” To keep everything running, we use industrial-grade connectors. We’ve seen too many cheap connections oxidize and fail in a hot kiln, so we don’t take shortcuts there.
The Reality of Installation
These units put out a massive amount of energy. It solves the uneven heating problem, but it takes up a lot of space and generates a ton of ambient heat. Don’t skimp on your fans. If your ventilation is weak, that heat will soak into your electrical housings. Once those connectors overheat, they fail. It’s as simple as that. I also suggest using independent PID controllers for each section of the tunnel. It gives you the freedom to fine-tune the temperature gradient exactly how you want it, rather than just guessing.