A switching system is activated by the torch rest. When the torch is in the cradle during warm-ups or between welds, compressed air is fed through the torch. When the torch is removed from the cradle for use nitrogen is automatically cut in and the compressed air is cut out. Other controls allow regulation of pressure and a fail-safe circuitry prevents burn out of elements, even if the inert gas supply is exhausted. Switches are interconnected to prevent the activation of the welding torch without the correct air/inert gas supply.
The LPNS is available separately or can be purchased as a complete welding kit – the Model 30-300.