PLASMA ARC COLLIMATOR DESIGN AND CONSTRUCTION

摘要

An improved collimator (102) for a plasma arc torch (12) consists of an annular holder member (104) and an insert member (118). The insert member (118) includes a tubular stem portion (120) ending in an integrally formed, radially extending face plate (122). When the stem portion (120) is fitted into the central bore (108) of the holder member (104) with a predetermined clearance fit therebetween, a cooling water passage (124) is created. The improved collimator is characterized by the absence of any welds between the holder member (104) and the insert member (118) that would be exposed to conductive gases given off during use of the plasma arc torch and a lesser resistance to cooling water flow than prior art collimator designs.