| 摘要 |
A submersible thermal processing apparatus including a welding torch having an electrode, a housing and an inlet for pressurized gas; a shielding gas nozzle mounted to the torch housing and surrounding at least a portion of the electrode; and a fluid-permeable baffle made of elastic, heat-resistant spring material arranged in a closed loop and mounted to a distal end of the shielding gas nozzle. This water exclusion device acts as a movable, flexible, gas-flow permeable baffle, and is used in contact with and/or close proximity to the workpiece surface. One preferred shape of the cross section of the device is elliptical, with the coils of the spring inclined at an angle to the general path around the device so as to allow the overall helix shape to be readily compressed and released through larger deflections than the conventional design of baffle. This shape allows the device to more easily conform to the work surface local and general undulations, thereby providing a more positive gas-to-water interface boundary. The baffling action of the device is to generate a path of high liquid flow resistance at the gas-liquid interface, while allowing an escape path for the continuously replenished inert gas flow which carries away the liquid vapor (such as steam) evaporated from the work surface.
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