Abstract: An airflow volume sensing system for determining the flow rate through a fan includes a curved inlet cone with a pressure sensor at the minimum diameter of the cone, wherein the flow volume sensing system is particularly suited for FC centrifugal fans (centrifugal fans with forward curved fan blades). With an FC fan, the minimum diameter of the inlet cones interior surface is adjacent the fan wheel, and the static pressure there is at a minimum value. A predetermined relationship between the static gage pressure at that point and the volume flow rate through the fan is applied regardless of variables such as fan speed, fan housing geometry, supply air duct configurations, return air duct configurations, location of various heat exchangers or filters, etc. In some examples, a single pressure sensor senses an average of a plurality of pressure taps wherein each tap is at approximately the same minimum pressure.

Abstract: An airflow volume sensing means for determining the flow rate through a fan includes a curved inlet cone with a pressure sensor at the minimum diameter of the cone, wherein the flow volume sensing means is particularly suited for FC centrifugal fans (centrifugal fans with forward curved fan blades). With an FC fan, the minimum diameter of the inlet cone's interior surface is adjacent the fan wheel, and the static pressure there is at a minimum value. A predetermined relationship between the static gage pressure at that point and the volume flow rate through the fan is applied regardless of variables such as fan speed, fan housing geometry, supply air duct configurations, return air duct configurations, location of various heat exchangers or filters, etc. In some embodiments, a single pressure sensor senses an average of a plurality of pressure taps, wherein each tap is at approximately the same minimum pressure.

Abstract: A fan inlet flow distributor comprises a skewed elliptical cone or equivalent body installed between an inlet opening of a centrifugal blower and an adjacent wall that faces the inlet. When all of the incoming airflow approaches the blower from the same general direction parallel to the wall and then makes a right turn to enter the blower's inlet, the unique shape of the flow distributor promotes a circumferentially uniform flow pattern as the air enters the fan's inlet. In some embodiments, the flow distributor comprises a skewed elliptical hyperboloid near its base and a skewed elliptical paraboloid near its vertex. The flow distributor is preferably attached to the wall and spaced apart from the fan's housing to ensure an unobstructed flow path between the distributor and the fan housing.

Abstract: A fan inlet flow distributor comprises a skewed elliptical cone or equivalent body installed between an inlet opening of a centrifugal blower and an adjacent wall that faces the inlet. When all of the incoming airflow approaches the blower from the same general direction parallel to the wall and then makes a right turn to enter the blower's inlet, the unique shape of the flow distributor promotes a circumferentially uniform flow pattern as the air enters the fan's inlet. In some embodiments, the flow distributor comprises a skewed elliptical hyperboloid near its base and a skewed elliptical paraboloid near its vertex. The flow distributor is preferably attached to the wall and spaced apart from the fan's housing to ensure an unobstructed flow path between the distributor and the fan housing.

Abstract: A centrifugal blower with forward curved fan blades includes an inlet shroud whose shape is specifically designed for creating a smooth incoming airflow pattern that leads into the inner leading edges of the fan blades. The inlet shroud has first and second curved surfaces, wherein the centers of curvature of the two surfaces lie in the same plane, and the center of curvature as well as the radius of curvature of one curved surface is greater than that of the other. At least one center of curvature lies beyond the outer diameter of the impeller, and at least one center of curvature lies beyond the impeller's inner diameter, wherein the impeller's inner diameter is defined by the inner leading edges of the fan blades. Performance benefits are achieved when a forward curved blower with such an inlet shroud operates with a flow coefficient of between 9 and 52.

Abstract: A centrifugal blower with forward curved fan blades includes an inlet shroud whose shape is specifically designed for creating a smooth incoming airflow pattern that leads into the inner leading edges of the fan blades. The inlet shroud has first and second curved surfaces, wherein the centers of curvature of the two surfaces lie in the same plane, and the center of curvature as well as the radius of curvature of one curved surface is greater than that of the other. At least one center of curvature lies beyond the outer diameter of the impeller, and at least one center of curvature lies beyond the impeller's inner diameter, wherein the impeller's inner diameter is defined by the inner leading edges of the fan blades. Performance benefits are achieved when a forward curved blower with such an inlet shroud operates with a flow coefficient of between 9 and 52.

Abstract: An air conditioning unit comprising: a housing having a first half and a second half; the first half of the housing containing an indoor heat exchange coil and a blower moving air through said coil from at least a housing inlet to a housing outlet. The blower discharges into a diffuser duct having a diffuser section with a first segment and a second segment where the first and second segments have first and second respective and differing angles of diffusion.

Abstract: An air conditioning unit comprising: a housing having a first half and a second half; the first half of the housing containing an indoor heat exchange coil and a blower moving air through said coil from at least a housing inlet to a housing outlet. The blower discharges into a diffuser duct having a diffuser section with a first segment and a second segment where the first and second segments have first and second respective and differing angles of diffusion.

Abstract: An air conditioning system. The system comprises an indoor section and an outdoor section arranged in side-by-side arrangement. The indoor section includes an indoor tangential fan having an axis aligned in a first direction, an indoor heat exchange coil, and a supply air aperture which longitudinally extends in the first direction and avoids line of sight noise transmission from the indoor fan. The system includes an axis commonly supporting and operably coupling the indoor fan and the motor, and a scroll housing within the indoor section and arranged about the indoor tangential fan. The indoor tangential fan, motor and axis are assembled to form a first module, the scroll housing forms a second module and the first module is independently removable from the second module without the necessity of disengaging any connection between the first and second modules. The system includes a fan support bracket supporting a first end of the axis, and the motor supporting a second end of the axis.

Abstract: A fan assembly. The fan assembly comprises: a fan having an axis and an outer periphery; a housing about the fan; and a cutoff separating fan inflow from fan outflow. The cutoff is preferably arranged parallel to the axis and is proximal to the outer periphery. The cutoff includes first and second layers. The first layer provides structural support and has a plurality of apertures therethrough. The second layer is formed of an acoustically insulating material.

Abstract: An air inlet and damper arrangement. The arrangement comprises a system housing with an external wall having a fresh air inlet; and an inlet air enclosure located within the system housing adjacent the external wall and arranged about the air inlet. The enclosure has an aperture connecting the interior of the enclosure with the interior of the system housing; and a damper sized to cover the aperture and pivotable within the small enclosure between a position covering the aperture and a position uncovering the aperture.

Abstract: An efficiency matching device and method. The efficiency matching device is utilized in combination with a centrifugal fan adapted to deliver an air mass flow through an air delivery system. The fan has a housing that defines an inlet port and an exit port. The fan additionally has an impeller disposed within the housing. The impeller draws air into the inlet port, accelerates the air, and discharges the air through the exit port. The efficiency matching device is shiftably carried within the exit port for selectively varying the area of the exit port such that the efficiency of the centrifugal fan can be varied to match the output efficiency of the fan to the desired air mass flow through the air delivery system.

Abstract: A centrifugal fan includes a housing that defines an air inlet leading to an air chamber defined within the fan impeller and an air exit port coupled to an air passageway. The housing includes a shroud that defines a two zone air passageway in the housing. The first zone, commencing adjacent to the base of the exhaust port, is a conformal portion that is conformal to the exterior diameter of the centrifugal fan and spaced slightly apart therefrom. The second zone of the shroud is a scroll portion wherein the angle of expansion is capable of expanding between 10.degree. and 15.degree.. An air restrictor plate is supported inside the air chamber of the centrifugal fan. At the greatest width of the air restrictor plate, the air restrictor plate subtends an arc that is substantially coextensive with the arc subtended by the first conformal zone of the shroud. The restrictor prevents the flow of inlet air through the centrifugal fan in the region of the conformal shroud.

Abstract: An air handling unit has a fan wheel in offset placement and a plenum configuration preventing line of sight noise transmission into the air system supplied by the air handling unit. The fan wheel is so placed and the plenum configuration optimized so as to obtain the benefit of an eddy current stabilizer flow from the fan wheel, which provides a further improvement in the acoustic performance of the air handling unit.

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.

Abstract: A condenser for an air conditioning or refrigeration system having first, second, third and fourth condenser coils arranged in a modified "W" arrangement.

Abstract: An outdoor heat exchanger section has lower and upper cabinet sections between which a generally horizontal louvered lower section top cover is disposed. The sides of the lower cabinet section are louvered to promote the entry and upward movement of air thereinto and through a heat exchange coil disposed about the inner periphery thereof. Air drawn into the lower cabinet section is discharged though the radially louvered portion of the lower section top cover. The radial top cover louvers are angled so as to partially deflect the upwardly flowing air leaving the lower cabinet section to the horizontal. The top of the upper cabinet section is essentially flat and solid and overlies the lower cabinet section top cover louvers so that neither debris nor the elements can enter the lower cabinet section from above.