Put Argon in too fast and from the wrong place and …..
For those people weld purging with Argon, consider that Argon, although a gas, will move to some extent as though it were a fluid.
A previous tip described the ideal purging method so:
On entering a volume to be purged, preferably as close to the bottom as possible, it will flood the base of the volume first, because it is heavier than air.
Then slowly as the volume begins to fill, it will push the air to the top of the volume and out of your purge exit, or exhaust port, which should be placed as high in the volume as possible.
Now imagine that your Argon feed line is a water hose, controlled by an normal tap/valve.
Pour water into a bucket from the top and it catches air on the way down and froths at the bottom. That is because air has been entrained in the pouring water and the water will be aerated.
Open to the tap too much and the water will spray out, entraining even more air.
OK for water.
But not OK if it were Argon entraining air, by being poured in too fast and from the wrong place.
Put Argon in too fast and from the wrong place and it will take much longer to purge your cavity and cost you much more in Argon.
When you cannot see something, visualisation of what is happening, is a good technique to understand the process.