The ornamental design for a flowmeterhousing, as shown and described.
FIG. 1 shows a front perspective view of a flow meter housing.
FIG. 2 shows a front view of the housing.
FIG. 3 shows a back view of the housing.
FIG. 4 shows a right side view of the housing.
FIG. 5 shows a left side view of the housing.
FIG. 6 shows a top view of the housing; and,
FIG. 7 shows a bottom view of the housing.
The broken line showing of structural features is included for the purpose of illustrating non-claimed subject matter and forms no part of the claimed design.