The ornamental design for a conveyorbeam, as shown and described.
FIG. 1 is a top-front perspective view of a conveyor beam, showing the design;
FIG. 2 is both a top plan view and a bottom plan view thereof;
FIG. 3 is both a front view and a rear view thereof; and,
FIG. 4 is both a left view and a right view thereof.
The conveyor beam has been shown with a symbolic break in its length. The appearance of any portion of the conveyor beam in the drawings between the break lines form no part of the claimed design.