I claim the ornamental design for a double containment coupling, as shown and described.
FIG. 1 is a perspective view of the double containment coupling in its environment with a pipe inserted in one end;
FIG. 2 is a front and top perspective view of the double containment coupling;
FIG. 3 is a side view of FIG. 2;
FIG. 4 is a top view of FIG. 2;
FIG. 5 is a rear view of FIG. 2;
FIG. 6 is a front view of FIG. 2;
FIG. 7 is an exploded view of FIG. 2 in a disassembled configuration;
FIG. 8 is an enlarged detailed view of the disassembled corner 8 shown in FIG. 7;
FIG. 9 is a cross sectional view of FIG. 8 taken along line 9-9; and,
FIG. 10 is a top sectional view of the disassembled configuration shown in FIG. 7 taken along line 10-10.
The dash dot broken lines depict environmental subject matter that forms no part of the claim. The dot dash broken line indicates cutoff boundaries for the enlarged detail portion view designated in FIGS. 7 and 8 and form no part of the claim.