I claim the ornamental design for an adapter for flow measuring unit, as shown and described.
FIG. 1 is a front and top perspective view of a first embodiment of an adapter for flow measuring unit of the present invention;
FIG. 2 is a rear and top perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a first side view thereof;
FIG. 6 is a second side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines shown represent unclaimed subject matter and form no part of the claimed design. Additionally, the unevenly broken lines in the drawings define the limits of the claimed design.