Abstract: Pressure variation absorbing apparatus is mounted adjacent to a moving fluid stream in the diffuser of a centrifugal compressor for absorbing both acoustic and aerodynamic pressure variations. The absorbing apparatus when mounted as a part of the diffuser wall of a centrifugal compressor not only reduces acoustic noise but also absorbs aerodynamic pressure variations increasing the efficiency of the compressor and simultaneously reducing the rate of flow at which surge occurs thereby enlarging the operational flow range of the compressor. A method of absorbing pressure variations in a moving fluid stream is also disclosed.

Abstract: Pressure variation absorbing apparatus is mounted adjacent to a moving fluid stream in the diffuser of a centrifugal compressor for absorbing both acoustic and aerodynamic pressure variations. The absorbing apparatus when mounted as a part of the diffuser wall of a centrifugal compressor not only reduces acoustic noise but also absorbs aerodynamic pressure variations increasing the efficency of the compressor and simultaneously reducing the rate of flow at which surge occurs thereby enlarging the operational flow range of the compressor. A method of absorbing pressure variations in a moving fluid stream is also disclosed.

Abstract: An air conditioning system including a ceiling air terminal operable to discharge conditioned air into a room and adapted to be connected to first and second sources of conditioned air. The first source provides air at a temperature level which varies inversely to changes in the outdoor air temperature. The air is discharged from the terminal along the ceiling towards the peripheral wall of the room to compensate for transmission gains or losses. The second source provides air at a predetermined temperature level. The air is discharged from the terminal along the ceiling of the room towards the interior thereof to compensate for the remaining cooling load therein, the volume of the air being varied in accordance with changes in the cooling load. The volume of the variable temperature air discharged into the room is maintained constant irrespective of changes in the pressure of the air supplied to the terminal.