The ornamental design for an evaporatorflask for a rotary evaporator, as shown and described.
FIG. 1 is a top plan view of an evaporator flask for a rotary evaporator,
showing my new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a side elevational view thereof, with all other side elevational
views being identical thereto, the broken line showing of the rotary
evaporator being for illustrative purposes only and forming no part of the
claimed design; and,