초록 ▼

In a ventilation system for a building in which air is extracted by a fan arrangement, an inlet flap arrangement is provided for a ceiling opening which comprises a foamed material flap member mounted directly covering the ceiling opening. The flap member is controlled by a tension spring biasing it

In a ventilation system for a building in which air is extracted by a fan arrangement, an inlet flap arrangement is provided for a ceiling opening which comprises a foamed material flap member mounted directly covering the ceiling opening. The flap member is controlled by a tension spring biasing it to a closed position so that its weight and air pressure act to open the flap. The angle of the spring relative to the position of the center of gravity of the flap member are controlled to provide the required opening characteristics. In one arrangement the flap member is shaped as a scoop so as to direct air along the ceiling when opened.

대표청구항 ▼

In a building having walls and a substantially horizontal ceiling defining a substantially closed interior area of the building, an air ventilation system comprising air extraction means for withdrawing air from the area, and an air inlet means separate from the air extraction means for allowing air

In a building having walls and a substantially horizontal ceiling defining a substantially closed interior area of the building, an air ventilation system comprising air extraction means for withdrawing air from the area, and an air inlet means separate from the air extraction means for allowing air into the area to replace air withdrawn therefrom, the air inlet means comprising an opening formed in the ceiling through which air can pass, a flap member, hinge means of said flap member being mounted directly on the ceiling for pivotal movement of the flap member about an axis along one side of the opening such that the flap member can move from a closed position covering the opening and preventing air movement therethrough to an open position in which the flap member extends from the axis downwardly to allow air to pass through the opening, and spring means biasing the flap member to a closed position.