Patent Application
20150184662
The field of the disclosure relates generally to centrifugal blower assemblies, and more specifically, to centrifugal blower assemblies that discharge air in a direction parallel to a motor rotational axis.
Blowers and impellers are commonly used for creating a flow of either a gas or a liquid. More specifically, blowers and impellers may be used in the automotive and air handling and ventilation industries for directing large volumes of forced air, over a wide range of pressures, through a variety of air conditioning components, such as furnaces. Furnaces utilize a blower to induce a draft through the furnace to draw combustion air into a combustion chamber of the furnace where the combustion air is mixed with fuel and ignited to produce heat for the furnace. The combustion products are drawn through a heat exchanger where the heat from the combustion products is transferred to temperature controlled circulating air which is directed through the house. The combustion products exit the heat exchanger and enter the furnace blower where they are propelled from the furnace blower through a discharge outlet into exhaust piping that leads to the outside atmosphere.
At least some known blower assemblies include an outlet that discharges air in a direction perpendicular to that of a rotational axis of the blower motor. However, at least some known furnaces require the use of existing exhaust piping to channel the discharge air out of vent openings in the furnace cabinet that are at permanent predetermined locations. Such hardware requires that the discharge air exits the blower outlet in a direction parallel to the motor rotational axis. Furthermore, the existing furnace exhaust piping has a generally circular cross-section, whereas at least some known blower assemblies include outlets having a generally rectangular cross-section. Thus, in order to couple the blower outlet to the exhaust piping, a structure is required that modifies the outlet airflow direction and that converts the rectangular blower outlet into a circular exhaust port that can be connected to the circular exhaust piping.
In one aspect, a blower assembly is provided. The blower assembly includes a motor including a rotational axis and a housing coupled to the motor. The housing includes an outlet portion configured to discharge an outlet airflow from the housing in a first direction that is substantially perpendicular to the rotational axis. The blower assembly also includes a transition piece coupled to the housing proximate the outlet portion. The transition piece includes a cylindrical body portion that is configured to direct the outlet airflow in a second direction that is substantially parallel to the rotational axis.
In another aspect, a furnace cabinet is provided. The furnace cabinet includes a plurality of panels including a mounting panel that at least partially defines a cavity. The furnace cabinet also includes a blower assembly coupled to the mounting panel within the cavity. The blower assembly includes a motor including a rotational axis and a housing coupled to the motor. The housing includes an outlet portion configured to discharge an outlet airflow from the housing in a first direction that is substantially perpendicular to the rotational axis. The blower assembly also includes a transition piece coupled to the housing proximate the outlet portion. The transition piece includes a cylindrical body portion that is configured to direct the outlet airflow in a second direction that is substantially parallel to the rotational axis.
In yet another aspect, a method of assembling a blower assembly is provided. The method includes providing a motor that includes a rotational axis. The method further includes coupling the motor to a housing. The housing includes an outlet portion configured to discharge an outlet airflow from the housing in a first direction that is substantially perpendicular to the rotational axis. A transition piece is then coupled to the housing proximate the outlet portion such that a cylindrical body portion of the transition piece is configured to direct the outlet airflow in a second direction that is substantially parallel to the rotational axis.
In the exemplary embodiment, blower assembly 102 is coupled to mounting panel 112 and is configured to produce a flow of air for air handling system 100. In the exemplary embodiment, air handling system 100 is one of a residential or a commercial HVAC system. Alternatively, air handling system 100 is any air moving system. Blower assembly 102 includes a blower housing 118 that may be made from stamped metal components, for example, or from suitable rigid plastics. Alternatively, housing 118 may be integrally formed as a single die cast piece of materials such as, but not limited to, aluminum and plastics. Blower housing 118 includes a top wall or end wall 120 and a side wall 122 extending substantially perpendicularly from end wall 120. Side wall 122 includes a flange 124 by which a cover member (not shown) may be secured to side wall 122 such as by separate mechanical fasteners, by crimping or welding. The cover member also includes a circular inlet opening 126 represented by dashed lines in
A motor 128 is coupled to and supported by end wall 120 of blower housing 118 via suitable fasteners (not shown) or some other equivalent connection. An impeller or fan wheel 130 is coupled to an output shaft 132 of motor 128 and is positioned within the interior of blower housing 118. In the exemplary embodiment, fan wheel 130 is a “squirrel cage” or “sirocco” type wheel that includes a plurality of blades 134 that are circumferentially spaced about a hub (not shown). In some known centrifugal blowers, blade shapes include one of a backward curved blade, an airfoil blade, a backward inclined blade, a forward curved blade, and a radial blade. In the exemplary embodiment, blades 134 are forward curved blades with respect to the rotation direction of fan wheel 130 and of air flow, indicated by arrow 136. Alternatively, fan wheel 130 may have any suitable blade shape, for example radial blades or airfoil blades, that enables blower assembly 102 to operate as described herein.
Output shaft 132 and fan wheel 130 rotate in the rotational direction 136 about a rotational axis 138. Rotational axis 138 defines mutually perpendicular axial and radial directions relative to blower assembly 102. There are no obstructions inside fan wheel 130 radially between motor output shaft 132 and plurality of blades 134 surrounding shaft 132. This enables an unobstructed flow of air axially through blower housing inlet opening 126 into the interior of fan wheel 130, then radially from motor output shaft 132 to fan blades 134 and through fan blades 134 around the outside of fan wheel 130 to blower housing side wall 122. Side wall 122 of blower housing 118 is generally curved or scrolled and extends in rotational direction 136 around fan wheel 130 between a housing cutoff 140, defined at a first end 142 of side wall 122, and a second end 144. In the exemplary embodiment, side wall 122, together with end wall 120 and optionally the cover member, define an outlet portion 146. Outlet portion 146 includes a substantially rectangular outlet edge 148 defined at least by distal ends of first and second side wall ends 142 and 144 and by an edge 150 of end wall 120. Outlet edge 150 defines an outlet opening 152 through which a stream of outlet airflow 154 is exhausted downstream of blower housing 118 in a first direction, illustrated by arrow 156 that is substantially perpendicular to rotational axis 138.
During operation, fan blades 134 rotate to draw air into an area of blower housing 118 proximate motor shaft 132 through inlet 126 and deflects the air radially outward from rotational axis 138. The air passes through channels defined between blades 134 and is forced outwards to side wall 122, due to the centrifugal force generated by rotating blades 134. The air is then channeled to outlet portion 146 before being exhausted from blower assembly 102 through outlet opening 152. Although blower assembly 102 is illustrated as having only one inlet 126, outlet 152, and fan wheel 130, blower assembly 100 may include any number of inlets, outlets, and fan wheels.
In the exemplary embodiment, blower assembly 102 further includes a transition piece 158 coupled to housing 118 proximate outlet portion 146. Transition piece 158 is configured to receive outlet airflow 154 from outlet opening 152 of outlet portion 146 and turn airflow 154 from first direction 156 to a second direction (not shown in
Transition piece 158 includes a substantially cylindrical body portion 160 that defines a longitudinal axis 162. Longitudinal axis 162 is parallel to rotational axis 138 of motor 128 and is offset from rotational axis 138 by a predetermined distance. Furthermore, longitudinal axis 162 is substantially perpendicular to first direction 156. In the exemplary embodiment, transition piece body portion 160 includes an aperture 164 (shown in
In the exemplary embodiment, transition piece 158 also includes a guide plate 163 coupled to an inner surface of body portion 160. More specifically, guide plate 163 is coupled within body portion 160 substantially across from aperture 164 and outlet opening 152. Guide plate 163 is configured prevent direct impingement of outlet airflow 154 onto body portion 160, which is oriented perpendicular to direction 164 of airflow 154. Furthermore, in the exemplary embodiment, guide plate 163 is curved such that outlet airflow 154 impinges on the curved surface and is directed towards the second direction within transition piece 158. Alternatively, guide plate 163 may be a substantially flat plate that is positioned at an angle with respect to first direction 156 to guide outlet airflow 154 along longitudinal axis 162 of body portion 160. Transition piece 158 is configured to receive outlet airflow 154 from outlet opening 152 of outlet portion 146 and turn airflow 154 from first direction 156 to the second direction, wherein the second direction is parallel to both rotational and longitudinal axes 138 and 162.
In the exemplary embodiment, aperture 164 extends from first end 178 substantially halfway along a length of body portion 160 toward second end 180. Alternatively, aperture 164 may extend any distance between any two points along body portion 160. Generally, aperture 164 has a shape that is complementary to the shape of outlet edge 148 such that there is no gap between aperture 164 and outlet portion 146. As described above, outlet edge 148 includes end wall edge 150 and both first and second ends 142 and 144 of side wall 122.
In the exemplary embodiment, transition piece 158 further includes a mounting plate 184 that extends inwards from inner surface 165 of body portion 160. Mounting plate 184 is a substantially flat plate that parallel to end wall 120 and is configured to couple transition piece 158 to outlet portion 146 of housing 118. More specifically, mounting plate 184 is coupled to a portion end wall 120 of outlet portion 146 using at least one fastener 186. Alternatively, mounting plate 184 may be coupled to outlet portion 146 by any comparable means, such as, but not limited to, brackets or welding. Mounting plate 184 includes a distal edge 188 that is substantially flush with outlet edge 148, and, more specifically, with edge 150 of end wall 120 such that mounting plate 184 extends a distance into body portion 160 approximately equal to the distance outlet portion 146 is inserted through aperture 164.
In operation, fan wheel 130 rotates about rotational axis 138 to drawn air into housing 118 through inlet 126. The air then passes through blades 134 and is exhausted from housing 118 through outlet opening 152 in first direction 156 substantially perpendicular to rotational axis 138. Outlet airflow 154 then flows into transition piece 160, which includes aperture 164 configured to receive at least a portion of housing outlet portion 146. Guide plate 163 is configured to direct outlet airflow 154 from first end 178 of transition piece body portion 160 in second direction 182 to second end 180 along longitudinal axis 162, which is parallel to rotational axis 138. Exhaust structure 166 is coupled to second end 180 of body portion 160 and channels outlet airflow 154 through at least one of top and/or side exhaust piping openings 114 and 116 located in top and side panels, respectively. By inserting the outlet portion of the housing assembly partially into the transition piece, the transition piece enables the use of pre-existing exhaust structure hardware with the exemplary blower assembly. The transition piece does so by turning the outlet airflow from its first direction as it exits the outlet perpendicular to the rotational axis to the second direction parallel with the rotational axis. Redirecting the outlet airflow substantially 90 degrees facilitates using the pre-existing exhaust structure to channel the outlet airflow form the blower assembly and to other components of the air handling system.
The embodiments described herein relate to a blower assembly including a transition piece and methods for assembling the same. More specifically, the embodiments relate to a blower assembly that includes a transition piece that turns an outlet airflow to enable use of existing exhaust piping to channel the airflow out of the blower assembly. More particularly, the embodiments relate to a blower assembly that includes a blower housing and a transition piece coupled to the outlet of the housing. The transition piece is configured to steer the outlet airflow from a first direction perpendicular to a motor rotational axis to a second direction parallel to the rotational axis. The methods and apparatus are not limited to the specific embodiments described herein, but rather, components of apparatus and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods may also be used in combination with a backward curved fan or blower assembly, and are not limited to practice with only the forward curved fan as described herein. In addition, the exemplary embodiment can be implemented and utilized in connection with many other residential or commercial HVAC applications.
Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
