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: In an air conditioning system, a damper unit disposed in the middle of a circulating duct is controlled so that a throttle valve of at least one of air quantity regulating devices for controlling incoming outside air quantity and exhaust air quantity is fully open, and that the quantity of air passing through the device whose throttle valve is fully open is equal to a set air quantity. The control system for the damper unit is so-called floating control system that is responsive to the control conditions. If none of the throttle valves of the devices is fully open, then there must be too great a pressure difference to pass the set quantity of air through all the devices. Accordingly, the excessive pressure applied to the devices can be lowered to a proper level by driving the damper unit in an opening direction, thereby reducing pressure loss between the discharging and charging blowers.

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.