The ornamental design for a dischargevalveassembly, as shown and described.
FIG. 1 is a top perspective view of a discharge valve assembly showing my new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a right side elevation view thereof, the left side elevation view, front elevation view and rear elevation view being a mirror image thereof;
FIG. 4 is a bottom view thereof; and,
FIG. 5 is a top plan view thereof.
The broken lines shown in the figures are included for the purpose of illustrating environment and form no part of the claimed design.