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US 5,207,557 AGranted
Centrifugal fan having variable width blades
AssigneeAmerican Standard Inc.
InventorsWilliam A. Smiley, III, George T. Brockman
Life of this patent
Estimating the term…
Abstract
A centrifugal fan has blades the effective width of which are variable during fan operation through the actuation of modulation apparatus which rotates with the fan wheel and is driven thereby. The modulation apparatus isolates the blocked off and unused portions of the fan blades which prevents the interaction of the blocked off portion of the blades with air flowing through the fan housing in a manner which results in a highly efficient and extremely quiet fan.
Claims14
A fan comprising:
- a housing defining an inlet;
- a fan wheel disposed for rotation in said housing, said fan wheel having a plurality of fan blades and a back plate;
- means, including a baffle member penetrated by and movable with respect to said fan blades, for modulating airflow through said housing, said baffle member rotating with said fan wheel and cooperating therewith to define effective and ineffective portions of said fan blades, said means for modulating airflow having a block off portion extending from said baffle member in a direction toward said back plate, said block off portion being a circumferential shroudlike member which is unattached to said back plate, said baffle member, said back plate and said shroud like member cooperating to isolate said ineffective portions of said fan blades from air flowing through said housing;
- means for supporting said modulating means for rotation with said fan wheel and for movement relative to said fan blades while said fan wheel is rotating;
- and
- means for causing the movement of said modulating means with respect to said fan blades while said fan wheel is rotating.
3 more elements
A fan comprising:
- a housing;
- a fan wheel disposed for rotation in said housing, said fan wheel having a plurality of fan blades and a back plate;
- means, including a baffle member axially movable of said fan blades and penetrated thereby for modulating airflow through said housing, said modulating means rotating with said fan wheel and cooperating therewith to define effective and ineffective portions of said fan blades, said modulating means including an expansible member attached to both said baffle member and said back plate, said ineffective portions of said fan blades being isolated from air flowing through said housing by said baffle member, said expansible member and said back plate;
- and
- means for causing the movement of said modulating means with respect to said fan blades while said fan wheel is rotating.
2 more elements
A fan comprising:
- a housing having a first and a second inlet;
- a fan wheel said fan wheel being a double width fan wheel having a first and a second set of fan blades;
- means, movable with respect to said first and said second set of fan blades, for modulating airflow through said housing, said means for modulating airflow including a first and a second baffle member, said first baffle member being penetrated by said first blade set and said second baffle member being penetrated by said second blade set, said first and said second baffle members each having a block off portion, the block off portion of said first baffle member being nestable within the block off portion of said second baffle member, said modulating means rotating with said fan wheel and cooperating therewith to define effective and ineffective portions of said fan blades, said ineffective portions being isolated from air flowing through said housing;
- and
- means for causing movement of said modulating means, said means for causing movement being operable to move said first and said second baffle members in opposite directions while said fan wheel is rotating.
2 more elements
What is claimed is a centrifugal fan comprising:
- a fan housing, said housing defining a first and a second inlet;
- a centrifugal fan wheel, said fan wheel being a double width fan wheel having a back plate fixedly mounted on a drive shaft and a first and a second set of fan blades extending from said back plate toward said first and said second fan inlets;
- means, axially moveable with respect to said drive shaft and rotatable with said fan wheel, for variably defining effective and ineffective portions of said first and said second set of said fan blades, said means for variably defining portions of said fan blades including a first and a second baffle member penetrated respectively by said first and said second set of fan blades, said first and said second baffle members each having a block off portion, the block off portion of said first baffle member being nested within the block off portion of said second baffle member when said means for variably defining effective and ineffective portions of said first and said second set of fan blades are positioned within said housing to define maximum effective portions of each of said blade sets, said first and said second baffle members, their respective block off portions and said back plate cooperating to isolate said ineffective portions of said first and said second sets of fan blades from air flowing through said fan housing;
- and
- means for causing the concurrent movement of said first and said second baffle members axially of said drive shaft in opposite directions while said fan wheel is rotating.
2 more elements
The centrifugal fan according to claim 16 further comprising bearing means disposed between said drive shaft and each of said transition portions.
Dependencies are inferred from the claim text.