I claim, the ornamental design for a blowout plug adapter, as shown and described.
FIG. 1 is an isometric view of a blowout plug adapter embodying my new design, with the phantom lines depicting a pneumatic hose quick-connect coupling and a conventional garden hose;
FIG. 2 is a side cross-sectional view of the blowout plug adapter, taken along line 2—2 as shown in FIG. 5, with phantom lines depicting a pneumatic hose with a quick-connect coupling receiver, a corresponding quick-connect coupling, and a conventional garden hose;
FIG. 3 is a side elevation view of the blowout plug adapter;
FIG. 4 is a top plan view of the blowout plug adapter; and,
FIG. 5 is bottom plan view of the blowout plug adapter.
Portions of the views shown in phantom in FIGS. 1 and 2 depict environmental structure, and form no part of the claimed design.