Welding purge dam with apertured purge plates

A weld zone purging installation, comprising:

• a pipe assembly comprising first and second pipes having respective first and second pipe ends to be welded together at a root gap;
• a water-degradable purge dam apparatus disposed in each of said first and second pipes proximate to said first and second pipe ends to define a weld zone spanning said root gap;
• said water-degradable purge dam apparatus, comprising:
• a blocking plate assembly having an outer blocking plate, an inner blocking plate and zero or more interior blocking plates;
• said blocking plate assembly comprising one or more water degradable materials to facilitate removal of said purge dam apparatus from said pipe assembly using an aqueous fluid following welding;
• and
• at least one of said blocking plates comprising a plurality of fluid flow apertures formed in a pattern to aid distribution of said aqueous fluid through said blocking plate assembly.

A water-degradable welding purge dam apparatus for purging a weld zone of a pipe assembly comprising first and second pipes having respective first and second pipe ends to be welded together at a root gap, said purge dam apparatus comprising:

• a ganged set of spaced-apart air flow blocking plate assemblies;
• each blocking plate assembly having an outer blocking plate, an inner blocking plate and zero or more interior blocking plates;
• said blocking plate assemblies being ganged together by an interconnection assembly that interconnects said blocking plate assemblies;
• said blocking plate assemblies and said interconnection assembly comprising one or more water degradable materials to facilitate removal of said purge dam apparatus from said pipe assembly using an aqueous fluid following welding;
• at least one of said blocking plates comprising a plurality of fluid flow apertures to aid distribution of said aqueous fluid through said blocking plate assemblies;
• each said blocking plate assembly comprising at least one pair of blocking plates in mutual facing engagement with each other, each blocking plate of said blocking plate pair having a plurality said fluid flow apertures;
• some or all of said fluid flow apertures in respective ones of said blocking plates in said blocking plate pair being at partially laterally overlapping relative to each other;
• said interconnection assembly comprising an interconnection structure having a wall surrounding a hollow interior, said interconnection structure wall comprising a plurality of fluid flow apertures to aid distribution of said aqueous fluid from said hollow interior to an exterior region outside said interconnection structure wall;
• each said blocking plate assembly comprising at least one friction plate having a plurality of flexible sidewall members on its periphery adapted to flexibly engage an inside wall of one of said first or second pipe ends;
• and
• said flexible members comprising flexible tabs defined by slits in said disk periphery.