The ornamental design for a valvediaphragm, as shown and described.
FIG. 1 is a top view of a valve diaphragm.
FIG. 2 is a bottom view of the valve diaphragm of FIG. 1.
FIG. 3 is a front view of the valve diaphragm of FIG. 1.
FIG. 4 is a back view of the valve diaphragm of FIG. 1.
FIG. 5 is a right side view of the valve diaphragm of FIG. 1.
FIG. 6 is a left side view of the valve diaphragm of FIG. 1; and,
FIG. 7 is an isometric view of the valve diaphragm of FIG. 1.
The broken lines shown in the figures are included for the purpose of illustrating portions of the valve diaphragm and form no part of the claimed design.