Patent ID: 11920818
Assignee: DAIKIN INDUSTRIES, LTD.
Field: nan (nan)
Classification: CPC nan | IPC F

Claim 0:
1. A fan unit connected to a predetermined unit through a duct, the fan unit comprising:
a fan with a variable rotation speed;
a casing that has an intake port and a blow-out port and houses the fan;
a controller that acquires a rotation speed of a fan motor that drives the fan; and
a detector that acquires a volume of air or a wind speed of the fan, wherein
the controller controls the rotation speed of the fan motor,
the controller determines whether or not a backflow in which air in the casing flows from the blow-out port toward the intake port occurs on a basis of the rotation speed and the volume of air or the wind speed, or on the basis of front-rear differential pressure that is a difference in air pressure between the intake port and the blow-out port of the casing, and
the controller calculates the front-rear differential pressure from the rotation speed and the volume of air or the wind speed on the basis of a relational expression that derives, from two values of the rotation speed, the volume of air or the wind speed, and the front-rear differential pressure, a remaining one value, and determines that the backflow occurs when the front-rear differential pressure has a negative value.