The ornamental design for a component of a liquidtreatment device, as shown and described.
FIG. 1 is a perspective view of a component of a liquid treatment device showing my new design.
FIG. 2 is a front elevation view thereof, the rear elevation being a mirror image thereof.
FIG. 3 is a right side elevation view thereof.
FIG. 4 is a left side elevation view thereof; and,
FIG. 5 is a top plan view thereof.
Portions of the component of a liquid treatment device not shown in the Figures form no part of the claimed design. The broken lines shown in the Figures are for illustrative purposes only and form no part of the claimed design.