| 摘要 |
<p>A plasma torch for spraying materials has a tube through which the wire or powder is supplied to the space where the plasma flame is formed, this tube passing through the cathode and opening into the region where the arc sparks. The tube runs from the point where it opens to the rear of the torch, passing through a water-cooled chamber. Coolant flows along the entire length of the chamber and then over the entire length of the tube by means of an intermediate baffle. Apart from wire or powder, gases may be introduced simultaneously or otherwise, as well as a type of radiation e.g. a laser beam. The torch can be used for flame spraying all metals including the most refractory. Owing to the high temps. it is possible to achieve a higher dispersion and consequently fine homogeneous deposits. Since the specific wt. of each particle is smaller, combustible or fusible materials can be coated without damaging them the amt. of calories supplied per unit area in a given time being smaller despite the higher temps. The torch may also be used for welding and cutting. Leakages of coolant into the arc region leading to damage of the torch are avoided by positioning seals away from hot zones.</p> |
