Flow rate measurement device and flow rate measurement method thereby

A flow rate measurement device comprising:

• a housing including an inlet port and a discharge port for a fluid, which are formed to face each other;
• a rotating portion including a rotating shaft arranged perpendicularly to a virtual line connecting the inlet port and the discharge port inside the housing, and a blade rotated by a flow of the fluid around the rotating shaft;
• a sensor portion arranged to be spaced apart from the rotating shaft in a radial direction of the rotating shaft so as to sense a number of rotations of the rotating portion;
• and
• a control portion that measures a flow rate of the fluid on the basis of the number of rotations of the rotating portion sensed by the sensor portion,
• wherein the sensor portion includes a first sensing portion installed to be spaced apart from the rotating shaft in the radial direction of the rotating shaft, and an interaction portion coupled radially to the blade such that the rotation of the rotating portion is recognized by an interaction with the first sensing portion,
• wherein the first sensing portion includes a first light emitting portion that generates light in an axial direction of the rotating shaft, and a first light receiving portion that is spaced apart from the first light emitting portion in the axial direction of the rotating shaft to receive the light emitted from the first light emitting portion,
• wherein the interaction portion includes one or more blocking portions arranged at an angle difference of 180°/N, where N is a natural number of 1 or more, to be able to alternately block and unblock an optical path between the first light emitting portion and the first light receiving portion by the rotation of the rotating shaft,
• wherein the housing includes:
• a lower housing including the inlet port and the discharge port which are formed to face each other, and an opening on an upper side;
• an upper housing coupled with the lower housing to cover the opening of the lower housing, and exposing a display portion of the control portion to outside;
• a sub-housing installed within the lower housing and supporting the rotating portion, and including a guide flow path formed to guide the fluid introduced through the inlet port toward the discharge port, and an opening on an upper side;
• and
• a cover member that covers the opening of the sub-housing and includes a first transparent guide groove protruding upward to guide the rotation of the interaction portion,
• wherein the first light emitting portion and the first light receiving portion are installed to face each other with respect to the first transparent guide groove.