HLQ®, Heraeus Lamp Quality is the trademark for electric fused undoped and doped quartz glass tubes made from natural sand – purified by the Heraeus refinement process. HLQ® is manufactured as single step tubing directly out of the Electric Fusion process (V-Zug), or as multi-step tubing out of the Reforming Furnace (S-Zug).
Single Step HLQ® is available as HLQ®200 (Un-doped), HLQ®235 (Titanium-oxide doped/ozone-free), or HLQ®382 (Cerium-Oxide doped/UV-blocking). Multi-Step HLQ® is available as HLQ®210 (undoped), and HLQ®270 (low alkaline). With additional annealing steps the OH-content is removable <1ppm depending on application and on request.