Abstract: A constant airflow control apparatus is connected to an air duct of an air conditioning system to keep the flow rate of air fed from the air duct constant. The apparatus comprises a rectangular pressure receiving plate slidably mounted on a guide shaft extending in one direction inside a passage of a housing. The plate extends substantially at right angles to the central axis of the housing so as to block part of the cross section of the passage. The apparatus further comprises a coil spring for urging the plate against the flow of the air, and two swinging plates swingably attached to two opposite side edges of the pressure receiving plate, individually. The swinging plates are adapted to change the cross-section area of an air passage defined between the swinging plates and the inner surface of the housing in a mode represented by a quadratic curve in accordance with a rectilinear change of the pressure of the air.

Abstract: An air flow rate sensor and throttle valve which controls the opening of a duct in accordance with the detection signals from the air flow rate sensor are provided in a control duct between a supply chamber utilizing double ceilings and the air diffusers in the supply chamber. The quantities of air fed from the respective air diffusers can be equalized or can be set to the desired values. In this case, since the air blowing can be automatically controlled for each diffuser, it is not necessary to individually adjust the quantities of air for the respective air diffusers after the installation of the air conditioner, thereby eliminating the adjusting works of the air diffusers.

Abstract: An air quantity regulating apparatus for air conditioning according to the present invention has two functions one of which is a constant air quantity function and the other is a variable air quantity function in cooperation with a room thermostat. When a constant air quantity control switch is turned on, the apparatus serves as the constant air quantity apparatus, on the other hand when the switch is turned off, the apparatus serves as the variable air quantity apparatus.

Abstract: Central air conditioning equipment which performs air conditioning for a plurality of rooms, comprises a terminal air quantity control unit which is installed in order to communicate with each room and which controls the quantity of the air stream which is distributed to each room through a duct, and an air quantity control device, attached to an air conditioner, which controls a blower to reduce the blown air quantity until at least one of dampers reaches a first position to allow air flow when all of the dampers are not in the first position, which controls the blower to decrease the blown air quantity when an air quantity detected by an air quantity sensor is smaller than an air quantity set by a setter while at least one of the dampers is located in the first position, and which controls the blower to maintain the blown air quantity when the air quantity detected by the air quantity sensor is equal to the air quantity set by the setter.