| 摘要 |
A device in a cutting torch which comprises a torch body with a valve housing and a nozzle and with a cutting oxygen duct, a heating oxygen duct and a combustion gas duct disposed in the torch, there being disposed in the torch a connection line which contains a throttling member between the heating oxygen duct and the cutting oxygen duct and wherein disposed in the cutting oxygen duct before the connection line is a valve member which permits a flow of heating oxygen to pass through the cutting oxygen duct only in the direction towards the orifice of the nozzle. The connection line between the heating oxygen duct and the cutting oxygen duct comprises at least one cooling oxygen duct (7) disposed in the nozzle which is elaborated with three sealing surfaces towards the torch body. The cooling oxygen duct (7) has a diameter which is so adapted in relation to the orifice diameter in the cutting oxygen duct of the nozzle and to the size of the heating flame that during heating of the workpiece a cooling oxygen pressure is rapidly built up in the cooling oxygen duct which prevents hot combustion gases from penetrating into the cutting oxygen ducts and that in the case of short nozzle distances to the workpiece the flow of cooling oxygen is prevented from becoming so great that the surface of the workpiece which is situated below the orifice of the cutting oxygen duct is cooled so rapidly that hole-piercing is rendered more difficult. |
