is positioned outdoors, originating at a bank of gas cylinders or from a large liquid-gas tank mounted on a concrete pad out in the yard — Fig. 1. From there, the piping may run up an outside wall before entering the building to supply the furnace — Fig. 2. The gas in these tanks is dry, but when the wrong tubing is used and is poorly positioned outside, significant moisture can be introduced throughout the length of the piping system that contaminates the gas delivered to the furnace. It is very important, therefore, that the entire piping system be clean and leak-tight to ensure the gas entering the furnace chamber is dry. To ensure drier gas delivery 1. Use only certified gas piping, 2. Seal the joints. Solder, braze, or weld all joints, or use O-ring seals, 3. Run the piping underground, and 4. Insulate the piping. Use Only Certified Gas Piping The standard copper and steel tubings sold at hardware stores are not suitable for this purpose. Unfortunately, today, piping is manufactured and supplied from many different locations worldwide. The walls of some of the inferior pipes and tubes are porous and can leak gas. Such poorquality piping is unacceptable for your use, you must install piping that is certified for use in gaseous atmospheres applications. PURGE 2-3 MINUTES! DAMS FOR ALL SIZES APRIL 2015 / WELDING JOURNAL 31 Fig. 2 — Gas piping exposed to the elements can become less air tight as the effects of temperature variations over time loosen the joints. PIPE WELDERS... PURGE PROBLEMS? INTERPURGE... IS YOUR SOLUTION! QUICK & ACCURATE PIPE ALIGNMENT PURGE MONITORS (OXYGEN TO 1PPM) ASSORTED PURGE KITS AVAILABLE WHY SETTLE FOR THIS? 316L Stainless w/ Argon Purge @ 250ppm Oxygen Level NOTE: 1% Oxygen in Atmosphere is 2,094.6 ppm! WHEN YOU CAN HAVE THIS! 316L Stainless w/ Argon Purge @ 12ppm Oxygen Level PERFECT PURGING = HIGH QUALITY WELDS For info, go to www.aws.org/adindex
Welding Journal | April 2015
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