A quartz tube furnace is an electric heating device extensively used in material research. For example, ceramic research, wafer sintering and annealing and powder baking and the quartz tube lengths will differ. For experiments in laboratories the size of tube is from 1" to 13", typically controlled by S-type thermocouples. The temperature controllers often allow the operator to program the heating, dwelling and cooling rates.
Fused quartz tubes
References
Quartz tube furnace Wikipedia(Text) CC BY-SA