Continuing from part 1, we have already covered “certified gas piping” and “all joints should be soldered, brazed, welded or O-ring sealed.”
To recap, it is very important that the entire piping system be as clean and leak-tight as possible to ensure that the gas used in the brazing furnace is as dry as possible (must be -60°F/-50°C or drier for effective brazing). To achieve this, the gas piping used should be:
2. All joints should be soldered, brazed, welded or O-ring sealed
3. Run piping underground if possible
4. Insulate piping if possible
3. Run gas piping underground
By running the pipe in the air, or along the outside walls of buildings, the piping and its fittings/connections will be subject to large temperature variations from day to night and from winter to summer. These combined forces of heating/cooling lead to extensive expansion/contraction issues with those pipes and fittings/connections, causing the joints to open up with time and lose their seal. If the piping is run underground from the gas tanks, it can be protected from such temperature extremes and minimize (or eliminate) any such sealing failures.
4. Insulate the pipes
Whether the piping is run underground or above ground, wrapping the pipes with insulation can be a distinct help in preventing temperature extremes from affecting the piping and all its connections.
It stands to reason that the optimal way to ensure that a protective atmosphere (either in liquid or gaseous form) being pumped from a storage tank can be most protected from losing its high quality is if it is piped to its destination using high-quality (certified) gas piping materials. Be sure that all connections are leak-tight by joining them using only soldering/brazing/welding procedures (no threaded plumbing fittings) before running the pipes underground to their destination. The additional use of pipe-insulation wrappings would be a plus.
Even with such care, there is typically still a slight loss of dew point in the gas when transferred from its original storage tank to the vacuum furnace using that protective-atmosphere gas. But such losses are minimal when compared to the significantly large dew-point losses (contamination) when piping is done as cheaply and as quickly as possible. This is done by merely buying some noncertified, standard piping procured from large national housing-supply chains, then installing it with regular threaded piping fittings, running the pipe up over driveways and roofs and then dropping them down into the building from high sidewalls or roofs.
Be wise. If you are planning to use a dry, non-oxidizing atmosphere in your furnace for brazing, heat treating, quenching, etc., do your best to be sure that the atmosphere reaches your furnace in the driest condition possible by taking the time and spending the money to correctly install that gas-piping system from your external gas-tank source all the way to your brazing furnace.