Method for pipe purging

A method of providing an inert atmosphere to the inside of a piping assembly prior to and during welding, comprising:

• introducing a cannister, and a deflated bladder which surrounds the cannister, into a piping assembly to be welded,
• introducing purge gas into a purge gas inlet connection fluidically connected to a bladder fill conduit, thereby inflating the deflated bladder and sealing the cannister against the inside of the piping assembly to be welded,
• introducing excess purge gas from the bladder, through a bladder return circuit into a pressure relief device, thereby producing a reduced pressure purge gas stream,
• introducing the reduced pressure purge gas stream into a primary purge gas diffuser, thereby producing a first diffused purge gas stream,
• introducing the first diffused purge gas stream into a secondary purge gas diffuser, thereby producing a secondary diffused purge gas stream,
• introducing the secondary diffused purge gas stream into a tertiary purge gas diffuser, thereby producing a third purge gas stream,
• introducing the third purge gas stream into the inside of the piping assembly to be welded.