抄録
An experimental study of a torch for oxygen plasma arc cutting (PAC) was conducted. We made a nozzle equipped with a window and a port for measurement. We observed the hafnium (Hf) electrode during working, using a color high-speed video camera through the window. The color image consists of three images assign red (R), green (G) and blue (B). Each image is taken by different image sensors having different wavelength sensitivity. We estimated the temperature on the surface of the Hf electrode assuming the black body radiation of the surface. And the port of the nozzle is connected to a pressure sensor to measure the pressure in the nozzle. We could estimate the real-time flow rate of plasma gas from the difference between the pressure in the nozzle and the pressure of supply.
Using the special nozzle for observation, we investigated the arc phenomena of PAC using an Hf electrode, during arc-start and arc-shut-off.
