Dealing with “Cold Spots” in Long Glass Tunnel Kilns
Most infrared lamps stop at 1.5 meters. If you’re running a long tunnel kiln, that’s a problem. Why? Because every time you hit a joint between two lamps, you get a cold spot. In the glass world, a cold spot is a recipe for disaster. That’s why we build custom quartz heaters that push past the 2-meter mark. We design them specifically for those long, continuous linear arrays where you just can’t afford a dip in temperature. The struggle with power and voltage You can’t just stretch a filament and call it a day. It doesn’t work like that. The longer the filament, the higher the electrical resistance. If you aren’t careful, the ends of your lamp will be lukewarm while the center is screaming hot. We spend a lot of time tweaking the voltage and wattage to keep things balanced. We’re basically fighting the ohms to make sure the heat stays flat and consistent from end to end. Just a heads-up: you’ll want to double-check your power supply. These custom loads can be heavy, and nobody likes a tripped breaker in the middle of a run. Keeping things steady We use high-purity quartz because it can take the thermal shock of a tunnel kiln without flinching. But there’s a catch. When a heater gets this long, it wants to sag. If that filament shifts even a little, you get a hot spot. And a hot spot means cracked glass. To stop that, we beef up the internal supports to keep everything centered. We also offer a few different end-cap options so the units slide right in without putting any weird stress on the quartz tube. A few things to watch for during install Wiring these arrays takes a bit of a steady hand. We use industrial connectors because they actually stay tight, which means you won’t have to worry about arcing when the current kicks in. One last thing. When you pack 2-meter heaters into a tight space, the ambient heat builds up fast. It gets hot. Make sure your cooling system can actually handle that load. If it can’t, you’re just cooking your own sockets and wiring harnesses, and that’s a headache you don’t need.