Abstract: A system for air-conditioning an installation having a number of rooms, the heat requirements of which are different and vary preferably with respect to time, which rooms are connected to a central air-conditioning unit. Light fixtures producing radiation heat are mounted in said rooms and are cooled in known manner by discharge air from the rooms to reduce the radiation heat. The temperature of the air from the central unit is maintained not higher than required for the room in the installation which has the greatest heat development, and the radiation heat from said light fittings is utilized and adjusted to additionally heat the rooms as described in U.S. Pat. No. 3,812,904. The adjustment provides maximum room heating by minimizing the cooling by the discharge air and minimum room heating by maximizing the cooling by the discharge air, minimum room ventilation flow being met when providing maximum heating and the flow increasing as heating is reduced.

Abstract: In pneumatic refuse systems, each vertical branch duct for receiving the refuse is normally connected to a main suction duct through a valve which, when closed, causes the refuse to be collected in the bottom of the branch duct and, when periodically opened, releases the accumulated refuse into the main duct. Liquid in the accumulated refuse also accumulates, undesirably, on the upper side of the valve. The invention provides an annular chamber positioned around the botttom of the branch duct, and circumferentially spaced-apart openings from the annular chamber to the interior of the branch duct at the level of the top of the valve, so that liquid accumulating at the bottom of the branch duct is collected in the annular chamber; a small bypass duct extends from the annular chamber to the adjacent main duct, so that the collected liquid is sucked out of the annular chamber and into the main duct, thereby clearing the valve of liquid.