US 11,920,818 B2
Fan unit and air treatment system including the same
Akira Komatsu, Osaka (JP); Shuuichi Tanaka, Osaka (JP); and Tooru Fujimoto, Osaka (JP)
Assigned to DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed on Feb. 2, 2023, as Appl. No. 18/105,125.
Application 18/105,125 is a continuation of application No. PCT/JP2021/028772, filed on Aug. 3, 2021.
Claims priority of application No. 2020-134853 (JP), filed on Aug. 7, 2020; and application No. 2020-161150 (JP), filed on Sep. 25, 2020.
Prior Publication US 2023/0204245 A1, Jun. 29, 2023
Int. Cl. F24F 11/77 (2018.01); F24F 11/74 (2018.01); F24F 110/40 (2018.01)
CPC F24F 11/77 (2018.01) [F24F 11/745 (2018.01); F24F 2110/40 (2018.01)] 9 Claims
OG exemplary drawing
 
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.