The ornamental design for a ventilationcase, as shown and described.
FIG. 1 is a front elevation view of the ventilation case showing the new design in a first state in which the door of the ventilation case is closed;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a front elevation view of the ventilation case showing the new design in a second state in which the door of the ventilation case is open, such that its inner design features can be seen.
The broken lines illustrate portions of the ventilation case and environmental structure. None of the broken lines form part of the claimed design.