초록 ▼

A centrifugal fan includes a fan wheel having airfoil blades mounted for pivotal movement about their center of gravity. A yoke mechanism exterior of the fan wheel, when moved axially of the fan wheel drive shaft axis, causes actuator rods to move through the sidewall of the fan wheel. The axial mov

A centrifugal fan includes a fan wheel having airfoil blades mounted for pivotal movement about their center of gravity. A yoke mechanism exterior of the fan wheel, when moved axially of the fan wheel drive shaft axis, causes actuator rods to move through the sidewall of the fan wheel. The axial movement of the actuator rods is translated first into rotary movement of a quill hub relative to the fan wheel and finally to radial movement of blade pivoting levers interior of the fan wheel. The movement of the blade pivoting levers causes the pitch of the individual fan blades to be changed in accordance with the degree of movement of the yoke mechanism. The yoke mechanism, actuator rods, quill hub and blade pivoting levers operate independently of the fan wheel so that blade pitch can be varied over an operating range irrespective of whether the fan wheel is stopped or is rotating. The yoke mechanism is moved and fan modulation is accomplished in response to the demand for conditioned air by the variable air volume system in which the fan is employed.

대표청구항 ▼

A centrifugal fan comprising: a fan housing having an inlet; a centrifugal fan wheel mounted for rotation in said fan housing and having a first sidewall, a back plate and a plurality of fan blades, each of said fan blades being mounted for rotation about a pivot axis over a predetermined operating

A centrifugal fan comprising: a fan housing having an inlet; a centrifugal fan wheel mounted for rotation in said fan housing and having a first sidewall, a back plate and a plurality of fan blades, each of said fan blades being mounted for rotation about a pivot axis over a predetermined operating range of rotation, the degree of rotation of a fan blade about its pivot axis being determinative of the pitch of the blade in said fan wheel, said first sidewall defining an inlet cooperating with said fan housing inlet to provide a flow path for air into the interior of said fan wheel and said back plate defining a mounting surface; a fan wheel driveshaft, said driveshaft penetrating and drivingly connected to said back plate so that driveshaft rotation causes the rotation of said fan wheel; hub means, mounted on said back plate mounting surface, for rotation around said driveshaft irrespective of the rotational speed of said back plate or driveshaft, said hub means connected to said fan blades so that rotation of said hub means around said driveshaft causes the pitch of said fan blades to change; a plurality of actuator rods penetrating and disposed for movement through said fan wheel back plate; and means for connecting said actuator rods to said hub means so that movement of said actuator rods through said back plate causes said hub means to rotate around said driveshaft.