Abstract: A sealed glass tube has a gaseous filling which when subjected to high voltage produces a radiation of energy through the tube. An elongated electrical conductor is mounted lengthwise in the tube and subjects the gaseous filling to high voltage to provide electrical communication with the exterior of the tube and form ozone with an encircling perforated metal grid. The tube is supported within the grid by spacers secured to internally facing valleys of the fluted grid. The flutes of the grid extend fully from one end to the other to provide maximum output. In a preferred form of the invention, the rearward end of the conductor is slidably supported to for expansion and contraction. Also, the conductor includes an auxiliary portion extending through and having sealed relation with one end of the tube, the auxiliary portion having a wound connection to the conductor.