The ornamental design for a device for mixingfluids, as shown and described.
FIG. 1 is a perspective view, from the back end, of an embodiment of a device for mixing fluids of the present invention;
FIG. 2 is an elevation view of the front end of the device of FIG. 1;
FIG. 3 is an elevation view of the back end of the device of FIG. 1;
FIG. 4 is a right side elevation view of the device of FIG. 1;
FIG. 5 is a left side elevation view of the device of FIG. 1;
FIG. 6 is a top plan view of the device of FIG. 1;
FIG. 7 is a bottom plan view of the device of FIG. 1; and,
FIG. 8 is a perspective view, from the front end, of the device of FIG. 1.
The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment and forms no part of the claimed design.