| 摘要 |
An air chamber assembly including two adjacently disposed fluorescent lighting units mounted in the ceiling of, for example, a commercial office or school, the assembly comprising an air chamber which is located within a space between the two lighting units and which is defined by a hollow air chamber casing, or air boot. The casing is formed with a ventilation air inlet duct through which air having the desired temperature and humidity may be supplied to the interior of the casing from a suitably located source of such air within the associated building. The assembly also comprises a support beam which is of inverted channel form in cross-section and which has a web portion, depending parallel limb portions, and outwardly directed flange portions projecting from the longitudinal edges of the limb portions of the beam remote from the web portion in a plane parallel to the plane containing the web portion. In certain embodiments of the invention, heat-fusible plates, rods or bodies are disposed between the web portion or the flange portions of the beam and the air chamber casing, thereby to maintain an edge portion of the casing a pre-determined spaced distance from the beam. In an alternative embodiment of the invention, heat-fusible strips are provided, each strip being secured to a portion of the casing which is pivotally mounted relative to the remainder of the casing, and to said remainder of the casing. Movement of the pivotal portions of the casing is thus prevented except on fusion of the heat-fusible strips, the pivotal portions of the casing each having an edge which is disposed in supported contact with the beam to maintain the above-mentioned edge portion of the casing at said pre-determined distance from the beam except on pivotal movement of the pivotal portions of the casing. The pre-determined spaced distance between the above-mentioned edge portion of the casing and the beam defines a ventilation air outlet duct through which ventilation air may flow from the interior of the casing to the room space or the like below the assembly, the casing being urged under gravity in the downward direction to cause this edge portion of the casing to enter into air-tight sealing contact with the flange portions of the beam on fusion of the heat-fusible plates, rods, bodies or strips.
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